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Griffiths KR, Breukelaar IA, Harvie G, Yang J, Foster SL, Harris AW, Clarke S, Hay PJ, Touyz S, Korgaonkar MS, Kohn MR. Functional Connectivity Mechanisms Underlying Symptom Reduction Following Lisdexamfetamine Treatment in Binge-Eating Disorder: A Clinical Trial. Biol Psychiatry Glob Open Sci 2024; 4:317-325. [PMID: 38298797 PMCID: PMC10829641 DOI: 10.1016/j.bpsgos.2023.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/03/2023] [Accepted: 08/21/2023] [Indexed: 02/02/2024] Open
Abstract
Background Speculation exists as to whether lisdexamfetamine dimesylate (LDX) acts on the functional connectivity (FC) of brain networks that modulate appetite, reward, or inhibitory control in binge-eating disorder (BED). Better insights into its action may help guide the development of more targeted therapeutics and identify who will benefit most from this medication. Here, we use a comprehensive data-driven approach to investigate the brain FC changes that underlie the therapeutic action of LDX in patients with BED. Methods Forty-six participants with moderate to severe BED received LDX titrated to 50 or 70 mg for an 8-week period. Twenty age-matched healthy control participants were also recruited. Resting-state functional magnetic resonance imaging was used to probe changes in brain FC pre- and post treatment and correlated with change in clinical measures. Results Ninety-seven percent of trial completers (n = 31) experienced remission or a reduction to mild BED during the 8-week LDX trial. Widespread neural FC changes occurred, with changes in default mode to limbic, executive control to subcortical, and default mode to executive control networks associated with improvements in clinical outcomes. These connections were not distinct from control participants at pretreatment but were different from control participants following LDX treatment. Pretreatment connectivity did not predict treatment response. Conclusions FC between networks associated with self-referential processing, executive function, and reward seem to underlie the therapeutic effect of LDX in BED. This suggests that LDX activates change via multiple systems, with most changes in compensatory networks rather than in those characterizing the BED diagnosis.
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Affiliation(s)
- Kristi R. Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- InsideOut Institute, University of Sydney, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Isabella A. Breukelaar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - Grace Harvie
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Jenny Yang
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Sheryl L. Foster
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- Department of Radiology, Westmead Hospital, Sydney, New South Wales, Australia
| | - Anthony W. Harris
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- Specialty of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Simon Clarke
- Centre for Research into Adolescents’ Health, University of Sydney, Sydney, New South Wales, Australia
- Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, New South Wales, Australia
| | - Phillipa J. Hay
- Translational Health Research Institute, School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Mental Health Services, Camden and Campbelltown Hospitals, South Western Sydney Local Health District, Sydney, New South Wales, Australia
| | - Stephen Touyz
- InsideOut Institute, University of Sydney, Sydney Local Health District, Sydney, New South Wales, Australia
- Clinical Psychology Unit, School of Psychology, University of Sydney, Sydney, New South Wales, Australia
| | - Mayuresh S. Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Michael R. Kohn
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- Centre for Research into Adolescents’ Health, University of Sydney, Sydney, New South Wales, Australia
- Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, New South Wales, Australia
- Clinical Psychology Unit, School of Psychology, University of Sydney, Sydney, New South Wales, Australia
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Okada M, Pehlivan MJ, Miskovic-Wheatley J, Barakat S, Griffiths KR, Touyz SW, Simpson SJ, Maguire S, Holmes AJ. My Diet Study: protocol for a two-part observational, longitudinal, psycho-biological study of dieting in Australian youth. Front Public Health 2023; 11:1281855. [PMID: 38155880 PMCID: PMC10752999 DOI: 10.3389/fpubh.2023.1281855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/14/2023] [Indexed: 12/30/2023] Open
Abstract
Introduction Self-directed dieting (i.e., unsupervised) is very common among adolescents and young adults but has had almost no direct research. This paper describes the protocol for the My Diet Study, a two-arm observational investigation of the natural progression of dieting among young people over a period of 6-months. The study aims to examine the links between self-directed dieting, general physiological and psychological metrics of wellbeing (e.g., depressive symptoms) and biomarkers of gut-brain axis functions (e.g., microbiome and hormones) that are predicted to influence diet adherence through appetite, mood and metabolism regulation. Methods Young people aged 16-25, intending to start a diet will be invited to participate in this observational study. For Part 1 (psychological arm), participants will be asked to complete a set of questionnaires and diaries at the beginning of every month for 6 months, to assess overall mental (e.g., psychological distress, disordered eating) and physical (e.g., weight) health, perceived diet success, food intake and gastrointestinal movements. For Part 2 (biological arm), a subsample of 50 participants will be asked to provide feces, blood and saliva for bio-sampling each month for the first 3-months of their participation in Part 1. Discussion The My Diet Study will be the first longitudinal, observational study of dieting in young people combining in-depth psychological and biological data. It is anticipated that the findings will yield psychological & biological information about the impacts and effectiveness of self-directed dieting in young people, inform a framework for advice on safety in dieting among young people and help to establish the potential for biomarkers for risk management and improvement of diet-based lifestyle interventions.
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Affiliation(s)
- Mirei Okada
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, Australia
| | - Melissa J. Pehlivan
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Jane Miskovic-Wheatley
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Sarah Barakat
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Kristi R. Griffiths
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Stephen W. Touyz
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Stephen J. Simpson
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, Australia
| | - Sarah Maguire
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- InsideOut Institute for Eating Disorders, The University of Sydney and Sydney Local Health District, Camperdown, NSW, Australia
| | - Andrew J. Holmes
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, Australia
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Perkes IE, Morris RW, Griffiths KR, Quail S, Waters F, O’Brien M, Hazell PL, Balleine BW. The Motivational Determinants of Human Action, Their Neural Bases and Functional Impact in Adolescents With Obsessive-Compulsive Disorder. Biol Psychiatry Glob Open Sci 2023; 3:1062-1072. [PMID: 37881550 PMCID: PMC10593889 DOI: 10.1016/j.bpsgos.2022.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Background Establishing the motivational influences on human action is essential for understanding choice and decision making in health and disease. Here we used tests of value-based decision making, manipulating both predicted and experienced reward values to assess the motivational control of goal-directed action in healthy adolescents and those with obsessive-compulsive disorder (OCD). Methods After instrumental training on a two action-two outcome probabilistic task, adolescents (n = 21) underwent Pavlovian conditioning using distinct stimuli predicting either the instrumental outcomes, a third outcome, or nothing. We then assessed functional magnetic resonance imaging during choice tests in which we varied the predicted value, using specific and general Pavlovian-instrumental transfer, and the experienced value, using outcome devaluation. To establish functional significance, we tested a matched cohort of adolescents with OCD (n = 20). Results In healthy adolescents, both predicted and experienced values influenced the performance of goal-directed actions, mediated by distinct orbitofrontal-striatal circuits involving the lateral orbitofrontal cortex (OFC) and medial OFC, respectively. However, in adolescents with OCD, choice was insensitive to changes in either predicted or experienced values. These impairments were related to hypoactivity in the lateral OFC and hyperactivity in the medial OFC during specific Pavlovian-instrumental transfer and hypoactivity in the anterior prefrontal cortex, caudate nucleus, and their connectivity in the devaluation test. Conclusions We found that predicted and experienced values exerted a potent influence on the performance of goal-directed actions in adolescents via distinct orbitofrontal- and prefrontal-striatal circuits. Furthermore, the influence of these motivational processes was severely blunted in OCD, as was the functional segregation of circuits involving medial and lateral OFC, producing dysregulated action control.
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Affiliation(s)
- Iain E. Perkes
- Decision Neuroscience Laboratory, University of New South Wales (UNSW) Sydney, Sydney, New South Wales, Australia
- Discipline of Psychiatry and Mental Health and Discipline of Paediatrics and Children’s Health, School of Clinical Medicine, Faculty of Medicine and Health, UNSW Sydney, Sydney, New South Wales, Australia
- Department of Psychological Medicine, Sydney Children’s Hospital Network, Sydney, New South Wales, Australia
| | - Richard W. Morris
- Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia
| | - Kristi R. Griffiths
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Stephanie Quail
- Decision Neuroscience Laboratory, University of New South Wales (UNSW) Sydney, Sydney, New South Wales, Australia
| | - Felicity Waters
- Child and Adolescent Mental Health Services, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Margot O’Brien
- Child and Adolescent Mental Health Services, Sydney Local Health District, Sydney, New South Wales, Australia
| | - Philip L. Hazell
- Child and Adolescent Mental Health Services, Sydney Local Health District, Sydney, New South Wales, Australia
- Specialty of Psychiatry, The University of Sydney, Sydney, New South Wales, Australia
| | - Bernard W. Balleine
- Decision Neuroscience Laboratory, University of New South Wales (UNSW) Sydney, Sydney, New South Wales, Australia
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Voetterl H, van Wingen G, Michelini G, Griffiths KR, Gordon E, DeBeus R, Korgaonkar MS, Loo SK, Palmer D, Breteler R, Denys D, Arnold LE, du Jour P, van Ruth R, Jansen J, van Dijk H, Arns M. Brainmarker-I Differentially Predicts Remission to Various Attention-Deficit/Hyperactivity Disorder Treatments: A Discovery, Transfer, and Blinded Validation Study. Biol Psychiatry Cogn Neurosci Neuroimaging 2023; 8:52-60. [PMID: 35240343 DOI: 10.1016/j.bpsc.2022.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 02/11/2022] [Accepted: 02/18/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder is characterized by neurobiological heterogeneity, possibly explaining why not all patients benefit from a given treatment. As a means to select the right treatment (stratification), biomarkers may aid in personalizing treatment prescription, thereby increasing remission rates. METHODS The biomarker in this study was developed in a heterogeneous clinical sample (N = 4249) and first applied to two large transfer datasets, a priori stratifying young males (<18 years) with a higher individual alpha peak frequency (iAPF) to methylphenidate (N = 336) and those with a lower iAPF to multimodal neurofeedback complemented with sleep coaching (N = 136). Blinded, out-of-sample validations were conducted in two independent samples. In addition, the association between iAPF and response to guanfacine and atomoxetine was explored. RESULTS Retrospective stratification in the transfer datasets resulted in a predicted gain in normalized remission of 17% to 30%. Blinded out-of-sample validations for methylphenidate (n = 41) and multimodal neurofeedback (n = 71) corroborated these findings, yielding a predicted gain in stratified normalized remission of 36% and 29%, respectively. CONCLUSIONS This study introduces a clinically interpretable and actionable biomarker based on the iAPF assessed during resting-state electroencephalography. Our findings suggest that acknowledging neurobiological heterogeneity can inform stratification of patients to their individual best treatment and enhance remission rates.
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Affiliation(s)
- Helena Voetterl
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Guido van Wingen
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Giorgia Michelini
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California; Department of Biological & Experimental Psychology, Queen Mary University of London, London, United Kingdom
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, New South Wales, Australia
| | | | - Roger DeBeus
- Department of Psychology, University of North Carolina at Asheville, Asheville, North Carolina
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, New South Wales, Australia; School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Sandra K Loo
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California
| | | | - Rien Breteler
- Department of Clinical Psychology, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Damiaan Denys
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - L Eugene Arnold
- Department of Psychiatry & Behavioral Health, Nisonger Center, Ohio State University, Columbus, Ohio
| | | | | | - Jeanine Jansen
- Open Mind Neuroscience, Eindhoven, the Netherlands; Eindhovens Psychologisch Instituut, Eindhoven, the Netherlands
| | - Hanneke van Dijk
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Martijn Arns
- Research Institute Brainclinics, Brainclinics Foundation, Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.
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5
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Rai S, Griffiths KR, Breukelaar IA, Barreiros AR, Boyce P, Hazell P, Foster SL, Malhi GS, Harris AWF, Korgaonkar MS. Common and differential neural mechanisms underlying mood disorders. Bipolar Disord 2022; 24:795-805. [PMID: 35972439 DOI: 10.1111/bdi.13248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Despite homogenous clinical presentations between bipolar and unipolar disorders, there are distinct neurobiological differences. Chronicity of illness may be a factor impacting and sustaining certain neural features. The goal of this study was to investigate common and shared neural mechanisms underlying mood disorders, and possible sustained neural changes relating to illness chronicity by investigating a cohort of euthymic patients with bipolar disorder (BD), unipolar depression who had responded to treatment (treatment-sensitive depression, TSD), and a chronically treatment-resistant depressed (TRD) group. METHODS One hundred and seventy-two participants (40 BD, 39 TSD, 40 TRD, and 53 age-gender-matched healthy controls) underwent resting-state fMRI scans. Seed-based and independent component analyses were performed to investigate group differences in resting-state connectivity between the four groups. RESULTS All three clinical groups had significantly lower connectivity within the frontoparietal network (FPN) relative to controls. TRD and BD were significantly different from TSD (TRD, BD > TSD) but were not significantly different from each other. TRDs were also significantly different from both BD and TSD for salience network connectivity with the posterior cingulate (DMN) and the FPN with frontal pole (DMN). Additionally, the BD group exhibited greater DMN-FPN (sgACC-RDLPFC) connectivity relative to TRD, TSD, and controls, which was correlated with a previous number of depressive episodes, in the BD group only. CONCLUSIONS BD demonstrated shared and differential connectivity features relative to symptomatic TRD and euthymic TSD groups. The increased sgACC-RDLPFC connectivity in BD and its correlation with a number of depressive episodes could be a neural feature associated with illness chronicity.
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Affiliation(s)
- Sabina Rai
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Westmead Clinical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia
| | - Isabella A Breukelaar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia.,School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - Ana R Barreiros
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Westmead Clinical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Philip Boyce
- Specialty of Psychiatry, The University of Sydney School of Medicine, Sydney, New South Wales, Australia
| | - Philip Hazell
- Specialty of Psychiatry, The University of Sydney School of Medicine, Sydney, New South Wales, Australia
| | - Sheryl L Foster
- Department of Radiology, Westmead Hospital, New South Wales, Australia.,Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Gin S Malhi
- Specialty of Psychiatry, The University of Sydney School of Medicine, Sydney, New South Wales, Australia.,Department of Psychiatry, CADE Clinic, Royal North Shore Hospital, Sydney, New South Wales, Australia.,Department of Psychiatry, University of Oxford, Oxford, UK
| | - Anthony W F Harris
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia.,Specialty of Psychiatry, The University of Sydney School of Medicine, Sydney, New South Wales, Australia
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, New South Wales, Australia.,Specialty of Psychiatry, The University of Sydney School of Medicine, Sydney, New South Wales, Australia.,Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
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Saad JF, Griffiths KR, Kohn MR, Braund TA, Clarke S, Williams LM, Korgaonkar MS. Intrinsic Functional Connectivity in the Default Mode Network Differentiates the Combined and Inattentive Attention Deficit Hyperactivity Disorder Types. Front Hum Neurosci 2022; 16:859538. [PMID: 35754775 PMCID: PMC9218495 DOI: 10.3389/fnhum.2022.859538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/20/2022] [Indexed: 12/24/2022] Open
Abstract
Neuroimaging studies have revealed neurobiological differences in ADHD, particularly studies examining connectivity disruption and anatomical network organization. However, the underlying pathophysiology of ADHD types remains elusive as it is unclear whether dysfunctional network connections characterize the underlying clinical symptoms distinguishing ADHD types. Here, we investigated intrinsic functional network connectivity to identify neural signatures that differentiate the combined (ADHD-C) and inattentive (ADHD-I) presentation types. Applying network-based statistical (NBS) and graph theoretical analysis to task-derived intrinsic connectivity data from completed fMRI scans, we evaluated default mode network (DMN) and whole-brain functional network topology in a cohort of 34 ADHD participants (aged 8–17 years) defined using DSM-IV criteria as predominantly inattentive (ADHD-I) type (n = 15) or combined (ADHD-C) type (n = 19), and 39 age and gender-matched typically developing controls. ADHD-C were characterized from ADHD-I by reduced network connectivity differences within the DMN. Additionally, reduced connectivity within the DMN was negatively associated with ADHD-RS hyperactivity-impulsivity subscale score. Compared with controls, ADHD-C but not ADHD-I differed by reduced connectivity within the DMN; inter-network connectivity between the DMN and somatomotor networks; the DMN and limbic networks; and between the somatomotor and cingulo-frontoparietal, with ventral attention and dorsal attention networks. However, graph-theoretical measures did not significantly differ between groups. These findings provide insight into the intrinsic networks underlying phenotypic differences between ADHD types. Furthermore, these intrinsic functional connectomic signatures support neurobiological differences underlying clinical variations in ADHD presentations, specifically reduced within and between functional connectivity of the DMN in the ADHD-C type.
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Affiliation(s)
- Jacqueline F Saad
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.,School of Medicine, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Michael R Kohn
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.,Centre for Research Into Adolescent's Health, Department of Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, NSW, Australia
| | - Taylor A Braund
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.,School of Medicine, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Black Dog Institute, University of New South Wales, Sydney, NSW, Australia.,School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Simon Clarke
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.,Centre for Research Into Adolescent's Health, Department of Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, NSW, Australia
| | - Leanne M Williams
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States.,Sierra Pacific Mental Illness Research Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, United States
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.,School of Medicine, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
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7
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Morris RW, Dezfouli A, Griffiths KR, Le Pelley ME, Balleine BW. The Neural Bases of Action-Outcome Learning in Humans. J Neurosci 2022; 42:3636-3647. [PMID: 35296548 PMCID: PMC9053851 DOI: 10.1523/jneurosci.1079-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 11/21/2022] Open
Abstract
From an associative perspective the acquisition of new goal-directed actions requires the encoding of specific action-outcome (AO) associations and, therefore, sensitivity to the validity of an action as a predictor of a specific outcome relative to other events. Although competitive architectures have been proposed within associative learning theory to achieve this kind of identity-based selection, whether and how these architectures are implemented by the brain is still a matter of conjecture. To investigate this issue, we trained human participants to encode various AO associations while undergoing functional neuroimaging (fMRI). We then degraded one AO contingency by increasing the probability of the outcome in the absence of its associated action while keeping other AO contingencies intact. We found that this treatment selectively reduced performance of the degraded action. Furthermore, when a signal predicted the unpaired outcome, performance of the action was restored, suggesting that the degradation effect reflects competition between the action and the context for prediction of the specific outcome. We used a Kalman filter to model the contribution of different causal variables to AO learning and found that activity in the medial prefrontal cortex (mPFC) and the dorsal anterior cingulate cortex (dACC) tracked changes in the association of the action and context, respectively, with regard to the specific outcome. Furthermore, we found the mPFC participated in a network with the striatum and posterior parietal cortex to segregate the influence of the various competing predictors to establish specific AO associations.SIGNIFICANCE STATEMENT Humans and other animals learn the consequences of their actions, allowing them to control their environment in a goal-directed manner. Nevertheless, it is unknown how we parse environmental causes from the effects of our own actions to establish these specific action-outcome (AO) relationships. Here, we show that the brain learns the causal structure of the environment by segregating the unique influence of actions from other causes in the medial prefrontal and anterior cingulate cortices and, through a network of structures, including the caudate nucleus and posterior parietal cortex, establishes the distinct causal relationships from which specific AO associations are formed.
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Affiliation(s)
- Richard W Morris
- Centre for Translational Data Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Amir Dezfouli
- Data61, Commonwealth Scientific and Industrial Research Organisation, Sydney, NSW 2015, Australia
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Sydney, NSW 2145, Australia
| | - Mike E Le Pelley
- School of Psychology, University of New South Wales Sydney, Sydney, NSW 2052, Australia
| | - Bernard W Balleine
- School of Psychology, University of New South Wales Sydney, Sydney, NSW 2052, Australia
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8
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Harvie G, Braund TA, Kohn MR, Korgaonkar MS, Clarke S, Williams LM, Griffiths KR. Cognitive and Executive Contributions to Trail-Making Task Performance on Adolescents With and Without Attention Deficit Hyperactivity Disorder. J Atten Disord 2022; 26:881-892. [PMID: 34384270 DOI: 10.1177/10870547211036743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The trail making task is used to assess executive functioning in ADHD youth, yet has only been validated in adult populations. We compare the relative contributions of various cognitive measures to performance on a trail making task analog, the Switching of Attention (SoA) task, in typically-developing and ADHD adolescents. METHOD Participants were 160 adolescents with ADHD from the International Study to Predict Optimized Treatment-in ADHD, assessed at pretreatment baseline and 6-week medicated follow-up, and 160 matched typically-developing peers. Attention, processing speed, working memory, impulsivity, and motor speed were assessed using a cognitive battery. RESULTS Processing speed and working memory significantly contributed to SoA performance in ADHD, regardless of medication status. While medicated, motor speed also underpinned the prediction of most task measures. For typically-developing adolescents, sustained attention and working memory contributed to SoA performance. CONCLUSION Typically-developing, unmedicated and treated ADHD adolescents recruit different aspects of cognition during SoA completion.
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Affiliation(s)
- Grace Harvie
- The Westmead Institute for Medical Research, NSW, Australia
| | | | - Michael R Kohn
- Westmead Hospital, NSW, Australia.,Westmead Hospital and The Sydney Children's Hospital Network, NSW, Australia
| | | | - Simon Clarke
- Westmead Hospital, NSW, Australia.,Westmead Hospital and The Sydney Children's Hospital Network, NSW, Australia
| | - Leanne M Williams
- Stanford University, CA, USA.,VA Palo Alto Health Care System, CA, USA
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9
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Rai S, Griffiths KR, Breukelaar IA, Barreiros AR, Chen W, Boyce P, Hazell P, Foster SL, Malhi GS, Harris AWF, Korgaonkar MS. Default-mode and fronto-parietal network connectivity during rest distinguishes asymptomatic patients with bipolar disorder and major depressive disorder. Transl Psychiatry 2021; 11:547. [PMID: 34689161 PMCID: PMC8542033 DOI: 10.1038/s41398-021-01660-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 09/21/2021] [Accepted: 10/01/2021] [Indexed: 11/08/2022] Open
Abstract
Bipolar disorder (BD) is commonly misdiagnosed as major depressive disorder (MDD). This is understandable, as depression often precedes mania and is otherwise indistinguishable in both. It is therefore imperative to identify neural mechanisms that can differentiate the two disorders. Interrogating resting brain neural activity may reveal core distinguishing abnormalities. We adopted an a priori approach, examining three key networks documented in previous mood disorder literature subserving executive function, salience and rumination that may differentiate euthymic BD and MDD patients. Thirty-eight patients with BD, 39 patients with MDD matched for depression severity, and 39 age-gender matched healthy controls, completed resting-state fMRI scans. Seed-based and data-driven Independent Component analyses (ICA) were implemented to examine group differences in resting-state connectivity (pFDR < 0.05). Seed analysis masks were target regions identified from the fronto-parietal (FPN), salience (SN) and default-mode (DMN) networks. Seed-based analyses identified significantly greater connectivity between the subgenual cingulate cortex (DMN) and right dorsolateral prefrontal cortex (FPN) in BD relative to MDD and controls. The ICA analyses also found greater connectivity between the DMN and inferior frontal gyrus, an FPN region in BD relative to MDD. There were also significant group differences across the three networks in both clinical groups relative to controls. Altered DMN-FPN functional connectivity is thought to underlie deficits in the processing, management and regulation of affective stimuli. Our results suggest that connectivity between these networks could potentially distinguish the two disorders and could be a possible trait mechanism in BD persisting even in the absence of symptoms.
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Affiliation(s)
- Sabina Rai
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia.
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia
| | - Isabella A Breukelaar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia
- School of Psychology, University of New South Wales, Sydney, NSW, Australia
| | - Ana R Barreiros
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia
| | - Wenting Chen
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia
| | - Philip Boyce
- Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Philip Hazell
- Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Sheryl L Foster
- Department of Radiology, Westmead Hospital, Sydney, NSW, Australia
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Gin S Malhi
- Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- CADE Clinic, Department of Psychiatry, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Anthony W F Harris
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia
- Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, Sydney, NSW, Australia.
- Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
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10
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Griffiths KR, Aparício L, Braund TA, Yang J, Harvie G, Harris A, Hay PJ, Touyz S, Kohn MR. Impulsivity and Its Relationship With Lisdexamfetamine Dimesylate Treatment in Binge Eating Disorder. Front Psychol 2021; 12:716010. [PMID: 34531798 PMCID: PMC8439192 DOI: 10.3389/fpsyg.2021.716010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/27/2021] [Indexed: 11/13/2022] Open
Abstract
High trait impulsivity is thought to contribute to the sense of loss of control over eating and impulses to binge eat experienced by those with binge eating disorder (BED). Lisdexamfetamine dimesylate (LDX), a drug approved for treatment of moderate to severe BED, has been shown to decrease impulsive features of BED. However, the relationship between LDX-related reductions of binge eating (BE) episodes and impulsivity has not yet been explored. Forty-one adults aged 18-40years with moderate to severe BED completed questionnaires and tasks assessing impulsivity at baseline and after 8weeks of 50-70mg of LDX. Twenty age-matched healthy controls were also assessed at two timepoints for normative comparison. Data were analysed using linear mixed models. BED participants exhibited increased self-reported motor, non-planning, cognitive and food-related impulsivity relative to controls but no differences in objective task-based measures of impulsivity. Food-related and non-planning impulsivity was significantly reduced by LDX, but not to normative levels. Individuals with higher baseline levels of motor and non-planning impulsivity, and loss of control over eating scores experienced the greatest reduction in BE frequency after 8weeks of LDX. Further, there were significant associations between the degree to which subjective loss of control over eating, non-planning impulsivity and BE frequency reduced after 8weeks of LDX. These data suggest that specific subjective measures of impulsivity may be able to predict who will have the greatest benefit from LDX treatment and that reductions in BE frequency may be moderated by concurrent reductions in non-planning impulsivity.
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Affiliation(s)
- Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
| | - Leonor Aparício
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia.,Faculty of Medicine, University of Porto, Porto, Portugal
| | - Taylor A Braund
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia.,BlackDog Institute, Sydney, NSW, Australia.,Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Jenny Yang
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
| | - Grace Harvie
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
| | - Anthony Harris
- Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia.,Discipline of Psychiatry, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Phillipa J Hay
- School of Medicine, Translational Health Research Institute, Western Sydney University, Sydney, NSW, Australia
| | - Stephen Touyz
- Clinical Psychology Unit, School of Psychology, University of Sydney, Sydney, NSW, Australia.,InsideOut Institute, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Michael R Kohn
- Centre for Research into Adolescents' Health (CRASH), University of Sydney, Sydney, NSW, Australia.,Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, NSW, Australia
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11
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Morandini HAE, Rao P, Hood SD, Zepf FD, Silk TJ, Griffiths KR. Age-related resting-state functional connectivity of the Vigilant Attention network in children and adolescents. Brain Cogn 2021; 154:105791. [PMID: 34509772 DOI: 10.1016/j.bandc.2021.105791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 11/25/2022]
Abstract
The development of Vigilant Attention (VA), the ability to focus and maintain our attention to repetitive and cognitively unchallenging tasks over time, has been investigated for more than a decade. The development of this critical executive function across the lifespan has been characterised by a rapid improvement in VA performance throughout childhood and adolescence, a steady improvement in adulthood and a slow decline in older adulthood. However, the development of the neural correlates of VA in children and adolescents remains poorly understood. Using a cross-sectional design, the present study used a meta-analytically defined VA network in children and adolescents to explore the developmental trend of the resting-state functional connectivity (rsFC) within the VA network across two independent cohorts. The results showed a linear and non-linear decrease of rsFC between the left and right VA brain regions across age. However, the results could not be reproduced in the replication cohort, potentially due to a smaller sample size. Based on previous findings from behavioural studies, the present findings suggest that changes in rsFC may underlie a developmental shift in cognitive strategies in neurotypical children and adolescents.
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Affiliation(s)
- Hugo A E Morandini
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia; Division of Psychiatry, UWA Medical School, Faculty of Health & Medical Sciences, The University of Western Australia, Australia.
| | - Pradeep Rao
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia; Telethon Kids Institute, Perth, Western Australia, Australia; Child and Adolescent Mental Health Service, Child and Adolescent Health Service, Perth, Australia
| | - Sean D Hood
- Division of Psychiatry, UWA Medical School, Faculty of Health & Medical Sciences, The University of Western Australia, Australia
| | - Florian D Zepf
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia; Telethon Kids Institute, Perth, Western Australia, Australia; Department of Child and Adolescent Psychiatry, Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Timothy J Silk
- School of Psychology, Deakin University, Geelong, Australia; Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Kristi R Griffiths
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia
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12
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Griffiths KR, Martin Monzon B, Madden S, Kohn MR, Touyz S, Sachdev PS, Clarke S, Foroughi N, Hay P. White matter microstructural differences in underweight adolescents with anorexia nervosa and a preliminary longitudinal investigation of change following short-term weight restoration. Eat Weight Disord 2021; 26:1903-1914. [PMID: 33051857 DOI: 10.1007/s40519-020-01041-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Anorexia nervosa (AN) affects approximately 2.9% of females and has the highest mortality rate among all psychiatric disorders. Despite several advances, the neurobiology of this disorder is still not well understood. Several studies have reported abnormalities in the white matter, but it is not know if these are disease-related or secondary to undernutrition. This study aimed to further our understanding of white matter pathology using diffusion-weighted imaging in underweight adolescents with AN, and to examine changes occurring after short-term weight restoration. METHODS Analyses were conducted on diffusion-weighted imaging from 24 female adolescents with AN and 17 age- and gender-matched healthy controls (HC), aged 14-19 years. Groups were compared on fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) using tract-based spatial statistics analysis and DTI measures were correlated with eating disorder examination questionnaire (EDE-Q) subscales and body mass index (BMI). Preliminary repeated-measure analyses were also conducted on eight participants after short-term weight restoration (median 41 days). RESULTS Widespread increases in MD of up to 9% were found in underweight AN relative to HC, particularly in the corpus callosum. This was associated with both increased AD and RD, suggestive of dys- or de-myelination. There were no significant group differences in FA, and no significant correlations between DTI measures, BMI or EDE-Q subscale score. Weight restoration therapy significantly reduced MD, to levels significantly lower than HC, but did not consistently alter FA across individuals. CONCLUSIONS White matter microstructure is significantly altered in female adolescents with AN, with preliminary longitudinal data suggesting that it may be reversible with short-term weight restoration. LEVEL OF EVIDENCE Level III: evidence obtained from well-designed cohort or case-control analytic studies.
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Affiliation(s)
- Kristi R Griffiths
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Rd, Westmead, Sydney, NSW, 2145, Australia.
| | - Beatriz Martin Monzon
- Translational Health Research Institute (THRI), School of Medicine, Western Sydney University, Sydney, Australia
| | - Sloane Madden
- School of Medicine, University of Sydney, Sydney, Australia
| | - Michael R Kohn
- Centre for Research Into Adolescents' Health (CRASH), University of Sydney, Sydney, Australia
| | - Stephen Touyz
- Clinical Psychology Unit, School of Psychology, University of Sydney, Sydney, Australia
| | - Perminder S Sachdev
- Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, and Neuropsychiatric Institute, The Prince of Wales Hospital, Sydney, Australia
| | - Simon Clarke
- Centre for Research Into Adolescents' Health (CRASH), University of Sydney, Sydney, Australia
| | - Nasim Foroughi
- Translational Health Research Institute (THRI), School of Medicine, Western Sydney University, Sydney, Australia
| | - Phillipa Hay
- Translational Health Research Institute (THRI), School of Medicine, Western Sydney University, Sydney, Australia
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13
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Saad JF, Griffiths KR, Kohn MR, Braund TA, Clarke S, Williams LM, Korgaonkar MS. No support for white matter connectivity differences in the combined and inattentive ADHD presentations. PLoS One 2021; 16:e0245028. [PMID: 33951031 PMCID: PMC8099057 DOI: 10.1371/journal.pone.0245028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/29/2021] [Indexed: 11/28/2022] Open
Abstract
Evidence from functional neuroimaging studies support neural differences between the Attention Deficit Hyperactivity Disorder (ADHD) presentation types. It remains unclear if these neural deficits also manifest at the structural level. We have previously shown that the ADHD combined, and ADHD inattentive types demonstrate differences in graph properties of structural covariance suggesting an underlying difference in neuroanatomical organization. The goal of this study was to examine and validate white matter brain organization between the two subtypes using both scalar and connectivity measures of brain white matter. We used both tract-based spatial statistical (TBSS) and tractography analyses with network-based Statistics (NBS) and graph-theoretical analyses in a cohort of 35 ADHD participants (aged 8–17 years) defined using DSM-IV criteria as combined (ADHD-C) type (n = 19) or as predominantly inattentive (ADHD-I) type (n = 16), and 28 matched neurotypical controls. We performed TBSS analyses on scalar measures of fractional anisotropy (FA), mean (MD), radial (RD), and axial (AD) diffusivity to assess differences in WM between ADHD types and controls. NBS and graph theoretical analysis of whole brain inter-regional tractography examined connectomic differences and brain network organization, respectively. None of the scalar measures significantly differed between ADHD types or relative to controls. Similarly, there were no tractography connectivity differences between the two subtypes and relative to controls using NBS. Global and regional graph measures were also similar between the groups. A single significant finding was observed for nodal degree between the ADHD-C and controls, in the right insula (corrected p = .029). Our result of no white matter differences between the subtypes is consistent with most previous findings. These findings together might suggest that the white matter structural architecture is largely similar between the DSM-based ADHD presentations is similar to the extent of being undetectable with the current cohort size.
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Affiliation(s)
- Jacqueline F. Saad
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Discipline of Psychiatry, Western Clinical School, The University of Sydney, Sydney, Australia
- * E-mail:
| | - Kristi R. Griffiths
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
| | - Michael R. Kohn
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Department of Adolescent and Young Adult Medicine, Centre for Research into Adolescents’ Health, Westmead Hospital, Sydney, New South Wales, Australia
| | - Taylor A. Braund
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Discipline of Psychiatry, Western Clinical School, The University of Sydney, Sydney, Australia
| | - Simon Clarke
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Department of Adolescent and Young Adult Medicine, Centre for Research into Adolescents’ Health, Westmead Hospital, Sydney, New South Wales, Australia
| | - Leanne M. Williams
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California, United States of America
- Sierra-Pacific Mental Illness Research, Education, and Clinical Center (MIRECC), VA Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Mayuresh S. Korgaonkar
- The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Discipline of Psychiatry, Western Clinical School, The University of Sydney, Sydney, Australia
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14
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Breukelaar IA, Griffiths KR, Harris A, Foster SL, Williams LM, Korgaonkar MS. Intrinsic functional connectivity of the default mode and cognitive control networks relate to change in behavioral performance over two years. Cortex 2020; 132:180-190. [PMID: 32987241 DOI: 10.1016/j.cortex.2020.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/31/2020] [Accepted: 08/23/2020] [Indexed: 10/23/2022]
Abstract
Understanding how brain circuitry mediates cognitive control of behavior is crucial for understanding both mental health and disease. Cognitive control describes the group of behaviors that guide goal-directed action such as sustaining attention, processing information and inhibiting impulsive responses. We rely on these behaviors for daily social, occupational and emotional functioning. Two brain networks, the cognitive control network (CCN) and default mode network (DMN), are thought to cooperate in an inverse relationship to support these functions. However, we do not yet know how connectivity within and between these networks directly relates to healthy cognitive control behaviors, and whether these interactions change over time. Here, we employed a longitudinal design to investigate if change in intrinsic connectivity in these networks will correlate with change in a range of cognitive control functions. Over two years, 109 healthy individuals, aged eight to thirty-eight, were tested twice using fMRI to assess intrinsic functional connectivity of the CCN and DMN and a validated cognitive battery. We found that increased within-network connectivity through central and left DMN was associated with increased memory performance. Additionally, decreased connectivity between posterior parietal CCN and DMN nodes and decreased connectivity between left and right dorsolateral prefrontal nodes was associated with increased cognitive performance. These findings were age and gender controlled, suggesting that age-independent plastic change in intrinsic connectivity through these networks directly relate to changing behavior. This has implications for targeting intrinsic connectivity as a possible mechanism to improve cognitive function.
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Affiliation(s)
- Isabella A Breukelaar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia.
| | - Kristi R Griffiths
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia
| | - Anthony Harris
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia; Discipline of Psychiatry, Sydney Medical School, Westmead, NSW, Australia
| | - Sheryl L Foster
- Department of Radiology, Westmead Hospital, Westmead, NSW, Australia; The Discipline of Medical Radiation Sciences, Faculty of Health Science, The University of Sydney, NSW, Australia
| | - Leanne M Williams
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia; Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; MIRECC, Palo Alto VA, Palo Alto, CA, USA
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia; Discipline of Psychiatry, Sydney Medical School, Westmead, NSW, Australia.
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15
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Saad JF, Griffiths KR, Korgaonkar MS. A Systematic Review of Imaging Studies in the Combined and Inattentive Subtypes of Attention Deficit Hyperactivity Disorder. Front Integr Neurosci 2020; 14:31. [PMID: 32670028 PMCID: PMC7327109 DOI: 10.3389/fnint.2020.00031] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/07/2020] [Indexed: 12/12/2022] Open
Abstract
Objective: Insights to underlying neural mechanisms in attention deficit hyperactivity disorder (ADHD) have emerged from neuroimaging research; however, the neural mechanisms that distinguish ADHD subtypes remain inconclusive. Method: We reviewed 19 studies integrating magnetic resonance imaging [MRI; structural (sMRI), diffusion, functional MRI (fMRI)] findings into a framework exploring pathophysiological mechanisms underlying the combined (ADHD-C) and predominantly inattentive (ADHD-I) ADHD subtypes. Results: Despite equivocal structural MRI results, findings from fMRI and DTI imaging modalities consistently implicate disrupted connectivity in regions and tracts involving frontal striatal thalamic in ADHD-C and frontoparietal neural networks in ADHD-I. Alterations of the default mode, cerebellum, and motor networks in ADHD-C and cingulo-frontoparietal attention and visual networks in ADHD-I highlight network organization differences between subtypes. Conclusion: Growing evidence from neuroimaging studies highlight neurobiological differences between ADHD clinical subtypes, particularly from a network perspective. Understanding brain network organization and connectivity may help us to better conceptualize the ADHD types and their symptom variability.
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Affiliation(s)
- Jacqueline Fifi Saad
- Brain Dynamics Centre, Westmead Institute for Medical Research, Westmead Hospital, Sydney, NSW, Australia.,The Discipline of Psychiatry, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia
| | - Kristi R Griffiths
- Brain Dynamics Centre, Westmead Institute for Medical Research, Westmead Hospital, Sydney, NSW, Australia.,The Discipline of Psychiatry, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, Westmead Institute for Medical Research, Westmead Hospital, Sydney, NSW, Australia.,The Discipline of Psychiatry, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia
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16
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Griffiths KR, Jurigova BG, Leikauf JE, Palmer D, Clarke SD, Tsang TW, Teber ET, Kohn MR, Williams LM. A Signature of Attention-Elicited Electrocortical Activity Distinguishes Response From Non-Response to the Non-Stimulant Atomoxetine in Children and Adolescents With ADHD. J Atten Disord 2019; 23:744-753. [PMID: 28974127 PMCID: PMC8215986 DOI: 10.1177/1087054717733044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Atomoxetine has several characteristics that make it an attractive alternative to stimulants for treating ADHD, but there are currently no tests identifying individuals for whom the medication should be a first-line option. METHOD Within the ADHD Controlled Trial Investigation Of a Non-stimulant (ACTION) study, we examined neuro-cortical activity in 52 youth with ADHD. Baseline event-related potentials (ERP) were compared between those who subsequently responded to 6 weeks of atomoxetine versus those who did not. RESULTS Responders were distinguished by significantly lower auditory oddball N2 amplitudes than both non-responders and typically developing controls, particularly in the right frontocentral region ( p = .002, Cohen's d = 1.1). Leave-one-out cross validation determined that N2 amplitude in this region was able to accurately predict non-responders with a specificity of 80.8%. There were no P3 differences between responders and non-responders. CONCLUSION The N2 amplitude is a biomarker that may have utility in predicting response to atomoxetine for youth with ADHD.
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Affiliation(s)
- Kristi R. Griffiths
- Brain Dynamics Centre, The Westmead Institue for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Barbora G. Jurigova
- Brain Dynamics Centre, The Westmead Institue for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - John E. Leikauf
- Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Donna Palmer
- Brain Resource, Sydney, New South Wales, Australia
| | - Simon D. Clarke
- Brain Dynamics Centre, The Westmead Institue for Medical Research, The University of Sydney, Westmead, New South Wales, Australia,Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, New South Wales, Australia,Centre for Research into Adolescents Health, Westmead, New South Wales, Australia
| | - Tracey W. Tsang
- Brain Dynamics Centre, The Westmead Institue for Medical Research, The University of Sydney, Westmead, New South Wales, Australia,Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, New South Wales, Australia
| | - Erdahl T. Teber
- Children's Medical Research Institute, Westmead, New South Wales, Australia
| | - Michael R. Kohn
- Brain Dynamics Centre, The Westmead Institue for Medical Research, The University of Sydney, Westmead, New South Wales, Australia,Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, New South Wales, Australia,Centre for Research into Adolescents Health, Westmead, New South Wales, Australia
| | - Leanne M. Williams
- Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
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17
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Griffiths KR, Yang J, Touyz SW, Hay PJ, Clarke SD, Korgaonkar MS, Gomes L, Anderson G, Foster S, Kohn MR. Understanding the neural mechanisms of lisdexamfetamine dimesylate (LDX) pharmacotherapy in Binge Eating Disorder (BED): a study protocol. J Eat Disord 2019; 7:23. [PMID: 31333843 PMCID: PMC6621979 DOI: 10.1186/s40337-019-0253-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 06/20/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The efficacy and safety of Lisdexamfetamine dimesylate (LDX) in the treatment of moderate to severe binge eating disorder (BED) has been demonstrated in multiple randomised clinical trials. Despite this, little is known about how LDX acts to improve binge eating symptoms. This study aims to provide a comprehensive understanding of the neural mechanisms by which LDX improves symptoms of BED. We hypothesise that LDX will act by normalising connectivity within neural circuits responsible for reward and impulse control, and that this normalisation will correlate with reduced binge eating episodes. METHODS This is an open-label Phase 4 clinical trial of LDX in adults with moderate to severe BED. Enrolment will include 40 adults with moderate to severe BED aged 18-40 years and Body Mass Index (BMI) of 20-45 kg/m2, and 22 healthy controls matched for age, gender and BMI. Clinical interview and validated scales are used to confirm diagnosis and screen for exclusion criteria, which include comorbid anorexia nervosa or bulimia nervosa, use of psychostimulants within the past 6 months, and current use of antipsychotics or noradrenaline reuptake inhibitors. Baseline assessments include clinical symptoms, multimodal neuroimaging, cognitive assessment of reward sensitivity and behavioural inhibition, and an (optional) genetic sample. A subset of these assessments are repeated after eight weeks of treatment with LDX titrated to either 50 or 70 mg. The primary outcome measures are resting-state intrinsic connectivity and the number of binge eating episodes. Analyses will be applied to resting-state fMRI data to characterise pharmacological effects across the functional connectome, and assess correlations with symptom measure changes. Comparison of neural measures between controls and those with BED post-treatment will also be performed to determine whether LDX normalises brain function. DISCUSSION First enrolment was in May 2018, and is ongoing. This study is the first comprehensive investigation of the neurobiological changes that occur with LDX treatment in adults with moderate to severe BED. TRIAL REGISTRATION ACTRN12618000623291, Australian and New Zealand Clinical Trials Registry URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374913&isReview=true. Date of Registration: 20 April 2018.
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Affiliation(s)
- Kristi R Griffiths
- 1The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145 Australia
| | - Jenny Yang
- 1The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145 Australia
| | - Stephen W Touyz
- 2School of Psychology, The University of Sydney, Camperdown, NSW 2050 Australia
| | - Phillipa J Hay
- 3Translational Health Research Institute, School of Medicine, Western Sydney University, Penrith, NSW 2751 Australia
| | - Simon D Clarke
- 1The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145 Australia.,4Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145 Australia.,Centre for Research into Adolescents Health, Westmead, NSW 2145 Australia
| | - Mayuresh S Korgaonkar
- 1The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145 Australia
| | - Linette Gomes
- 4Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145 Australia
| | - Gail Anderson
- 4Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145 Australia
| | - Sheryl Foster
- 6Department of Radiology, Westmead Hospital, Westmead, NSW Australia.,7The Discipline of Medical Radiation Sciences, Faculty of Health Science, The University of Sydney, Camperdown, NSW Australia
| | - Michael R Kohn
- 1The Brain Dynamics Centre, Westmead Institute for Medical Research, The University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145 Australia.,4Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145 Australia.,Centre for Research into Adolescents Health, Westmead, NSW 2145 Australia
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Griffiths KR, Leikauf JE, Tsang TW, Clarke S, Hermens DF, Efron D, Williams LM, Kohn MR. Response inhibition and emotional cognition improved by atomoxetine in children and adolescents with ADHD: The ACTION randomized controlled trial. J Psychiatr Res 2018; 102:57-64. [PMID: 29674270 PMCID: PMC9148271 DOI: 10.1016/j.jpsychires.2018.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 12/22/2022]
Abstract
Although the non-stimulant medication atomoxetine is effective for attention-deficit hyperactivity disorder (ADHD) in children and adolescents, there are still significant gaps in our knowledge about whether atomoxetine improves anxiety symptoms or cognition in children. Furthermore, while cognition has been proposed as an intermediate phenotype for ADHD dysfunction, the relationships between clinical and cognitive outcomes are not yet understood. We addressed these knowledge gaps in a controlled trial using objective assessments of both general and emotional cognitive functions implicated in ADHD and in anxiety, which commonly co-occurs with ADHD. A total of 136 children and adolescents with ADHD (ages 6-17years; 80% male; 31.6% with a comorbid anxiety disorder) were enrolled in a randomized double-blind, placebo-controlled, cross-over trial of 6-weeks treatment with atomoxetine. Of these, 109 completed the second cross-over phase. Selected cognitive domains associated with ADHD and anxiety disorders (Sustained attention, response inhibition and fearful face identification) were assessed using a normed, computerized test battery. Symptom outcomes were assessed by parent reports on the ADHD Rating Scale-IV and Conners' Anxious-Shy subscale. For completers, atomoxetine caused a greater improvement in the primary cognitive outcomes of response inhibition and fear identification compared to placebo, but not in sustained attention. Atomoxetine also improved ADHD and anxiety symptoms. Anxiety symptoms improved most for ADHD and anxiety disorder combined, but presence of an anxiety disorder did not moderate any other outcomes. Changes in cognitive and clinical outcomes were not correlated. These findings contribute to the foundations of measurement-based treatment planning and offer targets for probing the mechanisms of atomoxetine action.
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Affiliation(s)
- Kristi R. Griffiths
- The Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW 2145, Australia
| | - John E. Leikauf
- Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA 94305, USA
| | - Tracey W. Tsang
- The Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW 2145, Australia,Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - Simon Clarke
- The Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW 2145, Australia,Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145, Australia,Centre for Research Into Adolescents Health, Westmead, NSW 2145, Australia
| | - Daniel F. Hermens
- Sunshine Coast Mind and Neuroscience – Thompson Institute, University of the Sunshine Coast, Birtinya, Queensland 4575, Australia
| | - Daryl Efron
- Murdoch Childrens Research Institute, The Royal Children’s Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Leanne M. Williams
- Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA 94305, USA,Corresponding author. Psychiatry and Behavioral Sciences, Stanford University, 401 Quarry Rd, Mail Code 5717, Palo Alto, CA 94305, USA. (L.M. Williams)
| | - Michael R. Kohn
- The Brain Dynamics Centre, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW 2145, Australia,Adolescent & Young Adult Medicine, Westmead Hospital, Westmead, NSW 2145, Australia,Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, NSW 2006, Australia
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19
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Saad JF, Griffiths KR, Kohn MR, Clarke S, Williams LM, Korgaonkar MS. Regional brain network organization distinguishes the combined and inattentive subtypes of Attention Deficit Hyperactivity Disorder. Neuroimage Clin 2017; 15:383-390. [PMID: 28580295 PMCID: PMC5447655 DOI: 10.1016/j.nicl.2017.05.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 04/10/2017] [Accepted: 05/21/2017] [Indexed: 12/11/2022]
Abstract
Attention Deficit Hyperactivity Disorder (ADHD) is characterized clinically by hyperactive/impulsive and/or inattentive symptoms which determine diagnostic subtypes as Predominantly Hyperactive-Impulsive (ADHD-HI), Predominantly Inattentive (ADHD-I), and Combined (ADHD-C). Neuroanatomically though we do not yet know if these clinical subtypes reflect distinct aberrations in underlying brain organization. We imaged 34 ADHD participants defined using DSM-IV criteria as ADHD-I (n = 16) or as ADHD-C (n = 18) and 28 matched typically developing controls, aged 8–17 years, using high-resolution T1 MRI. To quantify neuroanatomical organization we used graph theoretical analysis to assess properties of structural covariance between ADHD subtypes and controls (global network measures: path length, clustering coefficient, and regional network measures: nodal degree). As a context for interpreting network organization differences, we also quantified gray matter volume using voxel-based morphometry. Each ADHD subtype was distinguished by a different organizational profile of the degree to which specific regions were anatomically connected with other regions (i.e., in “nodal degree”). For ADHD-I (compared to both ADHD-C and controls) the nodal degree was higher in the hippocampus. ADHD-I also had a higher nodal degree in the supramarginal gyrus, calcarine sulcus, and superior occipital cortex compared to ADHD-C and in the amygdala compared to controls. By contrast, the nodal degree was higher in the cerebellum for ADHD-C compared to ADHD-I and in the anterior cingulate, middle frontal gyrus and putamen compared to controls. ADHD-C also had reduced nodal degree in the rolandic operculum and middle temporal pole compared to controls. These regional profiles were observed in the context of no differences in gray matter volume or global network organization. Our results suggest that the clinical distinction between the Inattentive and Combined subtypes of ADHD may also be reflected in distinct aberrations in underlying brain organization. Structural connectome study of ADHD Inattentive and Combined subtypes. Neurobiological mechanisms underlying the ADHD subtypes remain unclear. Different profile of regional network measures characterized each subtype. Network organization differences were observed in context of preserved volume. Alterations of default mode network in ADHD Combined type than controls
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Key Words
- ACC, anterior cingulate cortex
- ADHD
- ADHD, Attention Deficit Hyperactivity Disorder
- ADHD-C, combined presentation
- ADHD-HI, predominantly hyperactive-impulsive
- ADHD-I, predominantly inattentive presentation
- ADHD-RS-IV, Attention Deficit/Hyperactivity Disorder Rating Scale
- CPRS-LV, Conners' Parent Rating Scale–Revised: Long Version
- Combined type
- DICA, Diagnostic Interview for Children and Adolescents
- DMN, default mode network
- DSM-V, Diagnostic Manual of Statistical Disorders fifth edition
- GM, gray matter
- Graph theory
- MINI Kid, Mini International Neuropsychiatric Interview
- MPH, methylphenidate
- Predominantly inattentive type
- Structural connectome
- Volume
- iSPOT-A, international study to predict optimized treatment in ADHD
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Affiliation(s)
- Jacqueline F Saad
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Australia; The Discipline of Psychiatry, University of Sydney Medical School: Western, Westmead Hospital, Australia
| | - Kristi R Griffiths
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Australia
| | - Michael R Kohn
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Australia; Centre for Research into Adolescents' Health, Department of Adolescent and Young Adult Medicine, Westmead Hospital, Australia
| | - Simon Clarke
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Australia; Centre for Research into Adolescents' Health, Department of Adolescent and Young Adult Medicine, Westmead Hospital, Australia
| | - Leanne M Williams
- Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; MIRECC, Palo Alto VA, Palo Alto, CA, USA
| | - Mayuresh S Korgaonkar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Australia; The Discipline of Psychiatry, University of Sydney Medical School: Western, Westmead Hospital, Australia.
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20
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Kozlowska K, Griffiths KR, Foster SL, Linton J, Williams LM, Korgaonkar MS. Grey matter abnormalities in children and adolescents with functional neurological symptom disorder. Neuroimage Clin 2017; 15:306-314. [PMID: 28560155 PMCID: PMC5440356 DOI: 10.1016/j.nicl.2017.04.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 03/28/2017] [Accepted: 04/12/2017] [Indexed: 11/18/2022]
Abstract
Objective Functional neurological symptom disorder refers to the presence of neurological symptoms not explained by neurological disease. Although this disorder is presumed to reflect abnormal function of the brain, recent studies in adults show neuroanatomical abnormalities in brain structure. These structural brain abnormalities have been presumed to reflect long-term adaptations to the disorder, and it is unknown whether child and adolescent patients, with illness that is typically of shorter duration, show similar deficits or have normal brain structure. Method High-resolution, three-dimensional T1-weighted magnetic resonance images (MRIs) were acquired in 25 patients (aged 10–18 years) and 24 healthy controls. Structure was quantified in terms of grey matter volume using voxel-based morphometry. Post hoc, we examined whether regions of structural difference related to a measure of motor readiness to emotional signals and to clinical measures of illness duration, illness severity, and anxiety/depression. Results Patients showed greater volumes in the left supplementary motor area (SMA) and right superior temporal gyrus (STG) and dorsomedial prefrontal cortex (DMPFC) (corrected p < 0.05). Previous studies of adult patients have also reported alterations of the SMA. Greater SMA volumes correlated with faster reaction times in identifying emotions but not with clinical measures. Conclusions The SMA, STG, and DMPFC are known to be involved in the perception of emotion and the modulation of motor responses. These larger volumes may reflect the early expression of an experience-dependent plasticity process associated with increased vigilance to others' emotional states and enhanced motor readiness to organize self-protectively in the context of the long-standing relational stress that is characteristic of this disorder. We used high-resolution MRI to investigate brain structure in children presenting with acute functional neurological symptom disorder (FND). Patients had multiple antecedent stressors, a long-standing history of relational stress and at-risk attachment strategies. Patients had greater volumes in the SMA—where motor-, cognitive-, and emotion-processing signals interact to influence motor function. FND may involve experience-dependent changes in brain structure alongside experience-dependent changes in brain function.
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Affiliation(s)
- Kasia Kozlowska
- The Children's Hospital at Westmead, Psychological Medicine, Locked Bag 4001, Westmead, NSW 2145, Australia; The Brain Dynamics Centre, Westmead Institute for Medical Research, 176 Hawkesbury Rd, Westmead, NSW 2145, Australia; The University of Sydney, Sydney, Australia.
| | - Kristi R Griffiths
- The Brain Dynamics Centre, Westmead Institute for Medical Research, 176 Hawkesbury Rd, Westmead, NSW 2145, Australia; The University of Sydney, Sydney, Australia.
| | - Sheryl L Foster
- The University of Sydney, Sydney, Australia; Westmead Hospital Radiology Department, Darcy Rd, Westmead, NSW 2145, Australia.
| | - James Linton
- The Brain Dynamics Centre, Westmead Institute for Medical Research, 176 Hawkesbury Rd, Westmead, NSW 2145, Australia.
| | - Leanne M Williams
- Psychiatry and Behavioral Sciences, Stanford University, VA Palo Alto (Sierra-Pacific MIRECC) 401 Quarry Rd, United States.
| | - Mayuresh S Korgaonkar
- The Brain Dynamics Centre, Westmead Institute for Medical Research, 176 Hawkesbury Rd, Westmead, NSW 2145, Australia; The University of Sydney, Sydney, Australia.
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21
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Griffiths KR, Quintana DS, Hermens DF, Spooner C, Tsang TW, Clarke S, Kohn MR. Sustained attention and heart rate variability in children and adolescents with ADHD. Biol Psychol 2017; 124:11-20. [DOI: 10.1016/j.biopsycho.2017.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 12/19/2022]
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Griffiths KR, Grieve SM, Kohn MR, Clarke S, Williams LM, Korgaonkar MS. Altered gray matter organization in children and adolescents with ADHD: a structural covariance connectome study. Transl Psychiatry 2016; 6:e947. [PMID: 27824356 PMCID: PMC5314130 DOI: 10.1038/tp.2016.219] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/25/2016] [Accepted: 09/20/2016] [Indexed: 01/28/2023] Open
Abstract
Although multiple studies have reported structural deficits in multiple brain regions in attention-deficit hyperactivity disorder (ADHD), we do not yet know if these deficits reflect a more systematic disruption to the anatomical organization of large-scale brain networks. Here we used a graph theoretical approach to quantify anatomical organization in children and adolescents with ADHD. We generated anatomical networks based on covariance of gray matter volumes from 92 regions across the brain in children and adolescents with ADHD (n=34) and age- and sex-matched healthy controls (n=28). Using graph theory, we computed metrics that characterize both the global organization of anatomical networks (interconnectivity (clustering), integration (path length) and balance of global integration and localized segregation (small-worldness)) and their local nodal measures (participation (degree) and interaction (betweenness) within a network). Relative to Controls, ADHD participants exhibited altered global organization reflected in more clustering or network segregation. Locally, nodal degree and betweenness were increased in the subcortical amygdalae in ADHD, but reduced in cortical nodes in the anterior cingulate, posterior cingulate, mid temporal pole and rolandic operculum. In ADHD, anatomical networks were disrupted and reflected an emphasis on subcortical local connections centered around the amygdala, at the expense of cortical organization. Brains of children and adolescents with ADHD may be anatomically configured to respond impulsively to the automatic significance of stimulus input without having the neural organization to regulate and inhibit these responses. These findings provide a novel addition to our current understanding of the ADHD connectome.
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Affiliation(s)
- K R Griffiths
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead Sydney, NSW, Australia
| | - S M Grieve
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead Sydney, NSW, Australia,Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre and Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - M R Kohn
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead Sydney, NSW, Australia,Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, NSW, Australia,Centre for Research into Adolescents' Health (CRASH), Sydney, NSW, Australia
| | - S Clarke
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead Sydney, NSW, Australia,Adolescent and Young Adult Medicine, Westmead Hospital, Sydney, NSW, Australia,Centre for Research into Adolescents' Health (CRASH), Sydney, NSW, Australia
| | - L M Williams
- Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA,Department of Sierra-Pacific MIRECC, VA Palo Alto Health Care System, Palo Alto, CA, USA,Psychiatry and Behavioral Sciences, Stanford University, 401 Quarry Road, Stanford, CA 94305, USA. E-mail:
| | - M S Korgaonkar
- Brain Dynamics Centre, The Westmead Institute for Medical Research, The University of Sydney, Westmead Sydney, NSW, Australia,Discipline of Psychiatry, Sydney Medical School, Westmead, Sydney, NSW, Australia
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Griffiths KR, Lagopoulos J, Hermens DF, Lee RSC, Guastella AJ, Hickie IB, Balleine BW. Impaired causal awareness and associated cortical-basal ganglia structural changes in youth psychiatric disorders. Neuroimage Clin 2016; 12:285-92. [PMID: 27551665 PMCID: PMC4983644 DOI: 10.1016/j.nicl.2016.06.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/11/2016] [Accepted: 06/22/2016] [Indexed: 02/06/2023]
Abstract
Background Cognitive impairments contribute significantly to disease burden in young individuals presenting with major psychiatric disorders. The capacity to encode the consequences of one's actions may be of particular importance for real-world functioning due to its fundamental role in goal-directed behavior. Methods Here, we investigated a dimensional measure of causal awareness during a probabilistic learning task in 92 young individuals with an admixture of major mood and psychotic illnesses, at early and more established stages. Using automated gray matter segmentation of T1-weighted images, we estimated the volume and shapes of major subcortical structures and investigated their association with causal awareness. Results The low causal awareness (LCA) group (n = 35) reported increased social disability (p = .004) and reduced right pallidal size, specifically within the dorsolateral surfaces (p = .02), relative to the unimpaired high causal awareness (HCA) patients (n = 57). In early-stage illness, LCA had a smaller right thalamus (p = .002) relative to HCA. Exploratory investigations suggested that in developed psychotic syndromes, causal awareness was correlated with left hippocampal size (p = .006) whereas, in more persistent affective disorders, causal awareness was correlated with left amygdala size (p = .013), specifically within the anterior aspect. Discussion Low causal awareness occurs across diagnoses and stages of illness and is associated with poor functional outcomes. Our results suggest that there may be shared neural underpinnings of its dysfunction in the early course of mood and psychotic disorders, however in more established illness, there is greater neurobiological divergence in causal awareness correlates between diagnoses. Impaired awareness of causal relationships occurs trans-diagnostically. Participants with low causal awareness have poorer functional outcomes. Low causal awareness was associated with reduced right pallidal size Low causal awareness was associated with a lateralized limbic-pallidal circuit. Results suggest common neural dysfunction in early mood and psychotic disorders.
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Affiliation(s)
| | | | | | - Rico S C Lee
- Brain and Mind Centre, University of Sydney, Australia
| | | | - Ian B Hickie
- Brain and Mind Centre, University of Sydney, Australia
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24
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Morris RW, Quail S, Griffiths KR, Green MJ, Balleine BW. Corticostriatal control of goal-directed action is impaired in schizophrenia. Biol Psychiatry 2015; 77:187-95. [PMID: 25062683 DOI: 10.1016/j.biopsych.2014.06.005] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND Goal-directed actions depend on our capacity to integrate the anticipated consequences of an action with the value of those consequences, with the latter derived from direct experience or inferred from predictive stimuli. Schizophrenia is associated with poor goal-directed performance, but whether this reflects a deficit in experienced or predicted value or in integrating these values with action-outcome information is unknown, as is the locus of any associated neuropathology. METHODS We assessed the contribution of these sources of value to goal-directed actions in people with schizophrenia (SZ) (n = 18) and healthy adults (n = 18). Participants learned to use specific actions to liberate snack foods from a vending machine. They also learned about the reward value of the foods, changes in reward value, and the relationship between various predictive stimuli and food delivery. We then evaluated the ability of subjects to use experienced or predicted value to guide goal-directed actions while undergoing functional magnetic resonance imaging. RESULTS Acquisition and sensitivity to experienced changes in outcome value did not differ in SZ and healthy adults. The SZ were, however, deficient in their ability to integrate action-outcome learning with outcome values to guide choice, more so when actions were guided by experienced than by predicted values. These effects were differentially associated with reductions in activity in caudate and limbic structures, respectively. CONCLUSIONS This novel assessment of goal-directed learning revealed dysfunction in corticostriatal control associated with a profound deficit in integrating changes in experienced value with the action-outcome association in schizophrenia.
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Affiliation(s)
- Richard W Morris
- Brain & Mind Research Institute, University of Sydney, Camperdown; Schizophrenia Research Institute, Darlinghurst, Australia
| | - Stephanie Quail
- Brain & Mind Research Institute, University of Sydney, Camperdown
| | | | - Melissa J Green
- Schizophrenia Research Institute, Darlinghurst, Australia; School of Psychiatry, University of New South Wales, Randwick, New South Wales, Australia
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25
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Lee RSC, Hermens DF, Scott J, Redoblado-Hodge MA, Naismith SL, Lagopoulos J, Griffiths KR, Porter MA, Hickie IB. A meta-analysis of neuropsychological functioning in first-episode bipolar disorders. J Psychiatr Res 2014; 57:1-11. [PMID: 25016347 DOI: 10.1016/j.jpsychires.2014.06.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/25/2014] [Accepted: 06/23/2014] [Indexed: 11/19/2022]
Abstract
Broad neuropsychological deficits have been consistently demonstrated in well-established bipolar disorder. The aim of the current study was to systematically review neuropsychological studies in first-episode bipolar disorders to determine the breadth, extent and predictors of cognitive dysfunction at this early stage of illness through meta-analytic procedures. Electronic databases were searched for studies published between January 1980 and December 2013. Twelve studies met eligibility criteria (N = 341, mean age = 28.2 years), and pooled effect sizes (ES) were calculated across eight cognitive domains. Moderator analyses were conducted to identify predictors of between-study heterogeneity. Controlling for known confounds, medium to large deficits (ES ≥ 0.5) in psychomotor speed, attention and working memory, and cognitive flexibility were identified, whereas smaller deficits (ES 0.20-0.49) were found in the domains of verbal learning and memory, attentional switching, and verbal fluency. A medium to large deficit in response inhibition was only detected in non-euthymic cases. Visual learning and memory functioning was not significantly worse in cases compared with controls. Overall, first-episode bipolar disorders are associated with widespread cognitive dysfunction. Since euthymia was not associated with superior cognitive performance in most domains, these results indicate that even in the earliest stages of disease, cognitive deficits are not mood-state dependent. The current findings have important implications for whether cognitive impairments represent neurodevelopmental or neurodegenerative processes. Future studies need to more clearly characterise the presence of psychotic features, and the nature and number of previous mood episodes.
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Affiliation(s)
- Rico S C Lee
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia; Department of Psychology, Macquarie University, Sydney, Australia.
| | - Daniel F Hermens
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Jan Scott
- Academic Psychiatry, Institute of Neuroscience, Newcastle University, UK; Centre for Affective Disorders, Institute of Psychiatry, London, UK
| | | | - Sharon L Naismith
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Jim Lagopoulos
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Kristi R Griffiths
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Melanie A Porter
- Department of Psychology, Macquarie University, Sydney, Australia
| | - Ian B Hickie
- Clinical Research Unit, Brain and Mind Research Institute, University of Sydney, Sydney, Australia
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Morris RW, Dezfouli A, Griffiths KR, Balleine BW. Action-value comparisons in the dorsolateral prefrontal cortex control choice between goal-directed actions. Nat Commun 2014; 5:4390. [PMID: 25055179 PMCID: PMC4124863 DOI: 10.1038/ncomms5390] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/13/2014] [Indexed: 11/29/2022] Open
Abstract
It is generally assumed that choice between different actions reflects the difference between their action values yet little direct evidence confirming this assumption has been reported. Here we assess whether the brain calculates the absolute difference between action values or their relative advantage, that is, the probability that one action is better than the other alternatives. We use a two-armed bandit task during functional magnetic resonance imaging and modelled responses to determine both the size of the difference between action values (D) and the probability that one action value is better (P). The results show haemodynamic signals corresponding to P in right dorsolateral prefrontal cortex (dlPFC) together with evidence that these signals modulate motor cortex activity in an action-specific manner. We find no significant activity related to D. These findings demonstrate that a distinct neuronal population mediates action-value comparisons, and reveals how these comparisons are implemented to mediate value-based decision-making. In humans, choice between actions depends on the ability to compare action–outcome values. Here, the authors show that action–outcome values are compared on the basis of the relative advantage of a particular action over alternative actions, which takes place in the right dorsolateral prefrontal cortex of the brain.
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Affiliation(s)
- Richard W Morris
- 1] Brain & Mind Research Institute, University of Sydney, Sydney, 2021 New South Wales, Australia [2]
| | - Amir Dezfouli
- 1] Brain & Mind Research Institute, University of Sydney, Sydney, 2021 New South Wales, Australia [2]
| | - Kristi R Griffiths
- Brain & Mind Research Institute, University of Sydney, Sydney, 2021 New South Wales, Australia
| | - Bernard W Balleine
- Brain & Mind Research Institute, University of Sydney, Sydney, 2021 New South Wales, Australia
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Griffiths KR, Morris RW, Balleine BW. Translational studies of goal-directed action as a framework for classifying deficits across psychiatric disorders. Front Syst Neurosci 2014; 8:101. [PMID: 24904322 PMCID: PMC4033402 DOI: 10.3389/fnsys.2014.00101] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/09/2014] [Indexed: 11/13/2022] Open
Abstract
The ability to learn contingencies between actions and outcomes in a dynamic environment is critical for flexible, adaptive behavior. Goal-directed actions adapt to changes in action-outcome contingencies as well as to changes in the reward-value of the outcome. When networks involved in reward processing and contingency learning are maladaptive, this fundamental ability can be lost, with detrimental consequences for decision-making. Impaired decision-making is a core feature in a number of psychiatric disorders, ranging from depression to schizophrenia. The argument can be developed, therefore, that seemingly disparate symptoms across psychiatric disorders can be explained by dysfunction within common decision-making circuitry. From this perspective, gaining a better understanding of the neural processes involved in goal-directed action, will allow a comparison of deficits observed across traditional diagnostic boundaries within a unified theoretical framework. This review describes the key processes and neural circuits involved in goal-directed decision-making using evidence from animal studies and human neuroimaging. Select studies are discussed to outline what we currently know about causal judgments regarding actions and their consequences, action-related reward evaluation, and, most importantly, how these processes are integrated in goal-directed learning and performance. Finally, we look at how adaptive decision-making is impaired across a range of psychiatric disorders and how deepening our understanding of this circuitry may offer insights into phenotypes and more targeted interventions.
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Affiliation(s)
- Kristi R Griffiths
- Behavioural Neuroscience Laboratory, Brain and Mind Research Institute, University of Sydney Camperdown, Sydney, NSW, Australia
| | - Richard W Morris
- Behavioural Neuroscience Laboratory, Brain and Mind Research Institute, University of Sydney Camperdown, Sydney, NSW, Australia
| | - Bernard W Balleine
- Behavioural Neuroscience Laboratory, Brain and Mind Research Institute, University of Sydney Camperdown, Sydney, NSW, Australia
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Reeves RA, Gibbs MD, Morris DD, Griffiths KR, Saul DJ, Bergquist PL. Sequencing and expression of additional xylanase genes from the hyperthermophile Thermotoga maritima FjSS3B.1. Appl Environ Microbiol 2000; 66:1532-7. [PMID: 10742238 PMCID: PMC92019 DOI: 10.1128/aem.66.4.1532-1537.2000] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/1999] [Accepted: 01/10/2000] [Indexed: 11/20/2022] Open
Abstract
Two genes, xynB and xynC, coding for xylanases were isolated from Thermotoga maritima FjSS3B.1 by a genomic-walking-PCR technique. Sequencing of the genes showed that they encode multidomain family 10 xylanases. Only XynB exhibited activity against xylan substrates. The temperature optimum (87 degrees C) and pH optimum (pH 6.5) of XynB are different from the previously reported xylanase, XynA (also a family 10 enzyme), from this organism. The catalytic domain expressed without other domains has a lower temperature optimum, is less thermostable, and has optimal activity at pH 6.5. Despite having a high level of sequence similarity to xynB, xynC appears to be nonfunctional since its encoded protein did not show significant activity on xylan substrates.
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Affiliation(s)
- R A Reeves
- Department of Biological Sciences, Macquarie University, Sydney New South Wales, Australia, New Zealand
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Abstract
In vitro excystation is commonly used to determine the viability of samples of purified Cryptosporidium parvum oocysts. Following exposure to conditions that stimulate excystation, samples are examined microscopically to determine the number of excysted oocysts. The microscopy procedure is tedious and time consuming, and difficult to apply to most oocyst samples without a purification step. A simple flow cytometric method was developed for determining the numbers of oocysts that had excysted following the in vitro excystation procedure. Differences in light-scatter properties were used to differentiate intact, partially empty and empty oocysts. By staining samples with a monoclonal antibody specific to the oocyst wall it was possible to apply the technique to unpurified oocysts from faeces. Correlation of the flow cytometric and microscopic method was statistically significant (P < 0.05), resulting in a calculated correlation coefficient of 0.994. The flow cytometry method is faster and more sensitive than the microscopy procedure, and enables analysis of large numbers of samples and of many thousands of oocysts in each sample.
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Affiliation(s)
- G Vesey
- Macquarie University Centre for Analytical Biotechnology, School of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
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30
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Abstract
Fluorescent labelling methods for detecting microorganisms in water have limited sensitivity partly due to the natural autofluorescence from environmental particles. The aim of this study was to examine the autofluorescence of water samples to determine the optimal excitation source and fluorescent labels for minimising background autofluorescence and therefore enhancing sensitive detection of Cryptosporidium oocysts. Particles concentrated from water were examined using fluorimetry at a wide range of excitation wavelengths to determine their autofluorescent properties. Two major peaks were identified emitting at 390 to 510 nm and at 640 to 700 nm. Flow cytometry was used to define the optical properties of oocysts immunofluorescently labelled with a range of fluorochromes. Concentrated water samples were analysed using flow cytometry and the number of particles with fluorescence and light scatter properties similar to the fluorescently labelled oocysts recorded. Fluorescein isothiocyanate exited at 488 nm was the most suitable label for oocysts in untreated water with less than 70 particles having optical properties similar to labelled oocysts, detected in 10 litre concentrates. The fluorochromes CY3, phycoerythrin (PE), and tetramethylrhodamine B thioisocyanate (TRITC) excited at 542 nm were the most suitable labels for oocysts in drinking water with less than 40 particles having optical properties similar to labelled oocysts, detected in 100 litre concentrates.
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Affiliation(s)
- G Vesey
- Macquarie University Centre for Analytical Biotechnology, School of Biological Sciences, Macquarie University, Sydney, Australia.
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31
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Abstract
Fluorescence-activated cell sorting was used to isolate five spores of the soil amoeba Dictyostelium discoideum that carried new glycosylation mutations, which were produced by restriction enzyme-mediated integration (REMI)-induced gene disruption and which occurred at frequencies of around 10(-5). These mutations were identified by the loss of an O-glycosylation epitope found on surface proteins of wild type D. discoideum spores that is recognised by the monoclonal antibody MUD62. A secondary antibody conjugated to the fluorochrome fluorescein isothiocyanate identified MUD62 bound to spores. Spores lacking this epitope did not fluoresce, allowing this population to be separated. Samples were found to contain around 0.1% of viable spores that were wild type but lacked the MUD62 epitope at the time of sorting. To remove these spores from the unlabelled population, samples were labelled with monoclonal antibody MUD50, which recognises surface proteins on immature spores and proteins exposed from an inner coat layer. Double labelling with MUD50 and MUD62 reduced the unlabelled viable population to less than 0.002%, allowing the glycosylation-defective spores to be isolated. This is the first use of a selective approach to isolate nonmorphological REMI-induced mutants in D. discoideum. This study also characterises the surface properties of spore types found in mature fruiting bodies of D. discoideum.
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Affiliation(s)
- K R Griffiths
- Macquarie University Centre for Analytical Biotechnology, School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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Coppock RL, Cavenagh AJ, Price KJ, Snow PJ, Shapland DE, Griffiths KR. Letter: A new service. Br Med J 1975; 1:629-30. [PMID: 1125645 PMCID: PMC1672785 DOI: 10.1136/bmj.1.5958.629-e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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