The limbic lobe and its output channels: implications for emotional functions and adaptive behavior

Changes in speech prosody perception during Parkinson's disease: A comprehensive analysis

INTRODUCTION

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects approximately 1%-2% of individuals aged 60 and above. Communication disorders in PD can significantly impact the overall quality of life. As prosody plays a vital role in verbal communication, the present study examines Persian prosody perception in PD, focusing on linguistic and emotional aspects of prosody.

METHODS

This cross-sectional study aimed to compare the perception of linguistic and emotional prosody in three groups: middle-aged adults (n = 22; mean age = 50.40 years), healthy older adults (n = 22; mean age = 68.31 years), and individuals with Parkinson's disease (n = 22; mean age = 65years). All individuals with PD were classified in stages 1; 1.5; 2; 2.5, and 3 of the disease using the Hoehn and Yahr scale. All participants had an MMSE score of 24 or above. The Florida Affect Battery (FAB) was used to evaluate prosody perception. This Battery was validated in the Persian language and its reliability and validity were reported as 94 % and 100 % respectively.

RESULTS

Participants with PD presented significantly lower scores than the older adults in all subtests of the FAB (p < 0.05), while healthy older adults were significantly different only in linguistic discrimination (β = -2.14; -3.68 to -0.61), and linguistic naming of prosody (β = 1.25; 0.17 to 2.33) compared to middle-aged adults.

CONCLUSIONS

The present study sheds light on the influence of PD on Persian prosody perception. Given the crucial role of prosody in verbal communication, these findings enhance our understanding of communication disorders in PD and could bring attention to consider prosody perception, among other aspects, when assessing individuals affected by PD.

The extended neural architecture of human attachment: An fMRI coordinate-based meta-analysis of affiliative studies

Functional imaging studies and clinical evidence indicate that cortical areas relevant to social cognition are closely integrated with evolutionarily conserved basal forebrain structures and neighboring regions, enabling human attachment and affiliative emotions. The neural circuitry of human affiliation is continually being unraveled as functional magnetic resonance imaging (fMRI) becomes increasingly prevalent, with studies examining human brain responses to various attachment figures. However, previous fMRI meta-analyses on affiliative stimuli have encountered challenges, such as low statistical power and the absence of robustness measures. To address these issues, we conducted an exhaustive coordinate-based meta-analysis of 79 fMRI studies, focusing on personalized affiliative stimuli, including one's infants, family, romantic partners, and friends. We employed complementary coordinate-based analyses (Activation Likelihood Estimation and Signed Differential Mapping) and conducted a robustness analysis of the results. Findings revealed cluster convergence in cortical and subcortical structures related to reward and motivation, salience detection, social bonding, and cognition. Our study thoroughly explores the neural correlates underpinning affiliative responses, effectively overcoming the limitations noted in previous meta-analyses. It provides an extensive view of the neural substrates associated with affiliative stimuli, illuminating the intricate interaction between cortical and subcortical regions. Our findings significantly contribute to understanding the neurobiology of human affiliation, expanding the known human attachment circuitry beyond the traditional basal forebrain regions observed in other mammals to include uniquely human isocortical structures.

Anatomical Organization of the Amygdala: A Brief Visual Review

The amygdala consists of a collection of nuclei that are deep within the medial temporal lobe. Despite its small size, the amygdala is one of the most densely connected structures in the brain, and it plays a role in many superior neural functions, including neurovegetative control, motor control, memory processing, and neuromodulation. Advances in neuroimaging technology for examining brain activity have opened up new ways of understanding the functional contribution of this structure to emotions, learning, and related memories. Many studies have shown that the amygdala plays a key role in the pathophysiology of neuropsychiatric disorders, such as anxiety disorders, depression, aggression, and temporal epilepsy. This article reviews the anatomical structure of the amygdaloid complex and the connectivity among its subdivisions and with other brain structures, which will serve as a basis for understanding the clinical correlations.

Sensing, Feeling, and Regulating: Investigating the Association of Focal Brain Damage with Voluntary Respiratory and Motor Control

Breathing is a complex, vital function that can be modulated to influence physical and mental well-being. However, the role of cortical and subcortical brain regions in voluntary control of human respiration is underexplored. Here we investigated the influence of damage to human frontal, temporal, or limbic regions on the sensation and regulation of breathing patterns. Participants performed a respiratory regulation task across regular and irregular frequencies ranging from 6 to 60 breaths per minute (bpm), with a counterbalanced hand motor control task. Interoceptive and affective states induced by each condition were assessed via questionnaire and autonomic signals were indexed via skin conductance. Participants with focal lesions to the bilateral frontal lobe, right insula/basal ganglia, and left medial temporal lobe showed reduced performance than individually matched healthy comparisons during the breathing and motor tasks. They also reported significantly higher anxiety during the 60-bpm regular and irregular breathing trials, with anxiety correlating with difficulty in rapid breathing specifically within this group. This study demonstrates that damage to frontal, temporal, or limbic regions is associated with abnormal voluntary respiratory and motor regulation and tachypnea-related anxiety, highlighting the role of the forebrain in affective and motor responses during breathing.

Highlights

Impaired human respiratory regulation is associated with cortical/subcortical brain lesionsFrontolimbic/temporal regions contribute to rhythmic breathing and hand motor controlFrontolimbic/temporal damage is associated with anxiety during tachypnea/irregular breathingThe human forebrain is vital for affective and interoceptive experiences during breathing.

MPP2 interacts with SK2 to rescue the excitability of glutamatergic neurons in the BLA and facilitate the extinction of conditioned fear in mice

AIMS

The basolateral amygdala (BLA) plays an integral role in anxiety disorders (such as post traumatic stress disorder) stem from dysregulated fear memory. The excitability of glutamatergic neurons in the BLA correlates with fear memory, and the afterhyperpolarization current (IAHP ) mediated by small-conductance calcium-activated potassium channel subtype 2 (SK2) dominates the excitability of glutamatergicneurons. This study aimed to explore the effect of MPP2 interacts with SK2 in the excitability of glutamatergic neurons in the BLA and the extinction of conditioned fear in mice.

METHODS

Fear memory was analyzed via freezing percentage. Western blotting and fluorescence quantitative PCR were used to determine the expression of protein and mRNA respectively. Electrophysiology was employed to measure the excitability of glutamatergic neurons and IAHP .

RESULTS

Fear conditioning decreased the levels of synaptic SK2 channels in the BLA, which were restored following fear extinction. Notably, reduced expression of synaptic SK2 channels in the BLA during fear conditioning was caused by the increased activity of protein kinase A (PKA), while increased levels of synaptic SK2 channels in the BLA during fear extinction were mediated by interactions with membrane-palmitoylated protein 2 (MPP2).

CONCLUSIONS

Our results revealed that MPP2 interacts with the SK2 channels and rescues the excitability of glutamatergic neurons by increasing the expression of synaptic SK2 channels in the BLA to promote the normalization of anxiety disorders and provide a new direction for the treatment.

Volume changes of the subcortical limbic structures in major depressive disorder patients with and without anhedonia

Anhedonia is a core feature of major depressive disorder (MDD) and the limbic system has been indicated to be associated with anhedonia in MDD due to its crucial role within the reward circuit. However, the relationship between different regions of the limbic system and MDD, particularly anhedonic symptoms, remains unclear. Therefore, the purpose of this study was to investigate volume changes of various parts of the subcortical limbic (ScLimbic) system in MDD with and without anhedonia. A total of 120 individuals, including 30 MDD patients with anhedonia, 43 MDD patients without anhedonia, and 47 healthy controls (HCs) were enrolled in this study. All subjects underwent structural magnetic resonance imaging scans. After that, ScLimbic system segmentation was performed using the FreeSurfer pipeline ScLimbic. Analysis of covariance (ANCOVA) was performed to identify brain regions with significant volume differences among three groups, and then, post hoc tests were calculated for inter-group comparisons. Finally, correlations between volumes of different parts of the ScLimbic and clinical characteristics in MDD patients were further analyzed. The ANCOVA revealed significant volume differences of the ScLimbic system among three groups in the bilateral fornix (Fx), and the right basal forebrain (BF). As compared with HCs, both groups of MDD patients showed decreased volume in the right Fx, meanwhile, MDD patients with anhedonia further exhibited volume reductions in the left Fx and right BF. However, no significant difference was found between MDD patients with and without anhedonia. No significant association was observed between subregion volumes of the ScLimbic system and clinical features in MDD. The present findings demonstrated that MDD patients with and without anhedonia exhibited segregated brain structural alterations in the ScLimbic system and volume loss of the ScLimbic system might be fairly extensive in MDD patients with anhedonia.

The anterior perforated substance (APS) revisited: Commented anatomical and imagenological views

INTRODUCTION

Since 2002, when we published our article about the anterior perforated substance (APS), the knowledge about the region has grown enormously.

OBJECTIVE

To make a better description of the anatomy of the zone with new dissection material added to the previous, to sustain the anatomical analysis of the MRI employing the SPACE sequence, interacting with our imagenology colleagues. Especially, we aim to identify and topographically localize by MRI the principal structures in APS-substantia innominata (SI).

METHOD

The presentation follows various steps: (1) location and boundaries of the zone and its neighboring areas; (2) schematic description of the region with simple outlines; (3) cursory revision of the SI and its three systems; (4) serial images of the dissections of the zone and its vessels, illustrated and completed when possible, by MRI images of a voluntary experimental subject (ES).

RESULTS

With this method, we could expose most of the structures of the region anatomically and imagenologically.

DISCUSSION

The zone can be approached for dissection with magnification and the habitual microsurgical instruments with satisfactory results. We think that fibers in this region should be followed by other anatomical methods in addition to tractography. The principal structures of ventral striopallidum and extended amygdala (EA) can be identified with the SPACE sequence. The amygdala and the basal ganglion of Meynert (BGM) are easily confused because of their similar signal. Anatomical clues can orient the clinician about the different clusters of the BGM in MRI.

CONCLUSIONS

The dissection requires a previous knowledge of the zone and a good amount of patience. The APS is a little space where concentrate essential vessels for the telencephalon, "en passage" or perforating, and neural structures of relevant functional import. From anatomical and MRI points of view, both neural and vascular structures follow a harmonious and topographically describable plan. The SPACE MRI sequence has proved to be a useful tool for identifying different structures in this area as the striatopallidal and EA. Anatomical knowledge of the fibers helps in the search of clusters of the basal ganglion.

Dynamic evolution of the anterior cingulate-insula network during seizures

OBJECTIVES

In physiological situations, the anterior cingulate cortex (ACC) and anterior insular cortex (AIC) are prone to coactivation. The functional connectivity and interaction between ACC and AIC in the context of epilepsy remain unclear. This study aimed to investigate the dynamic coupling between these two brain regions during seizures.

METHODS

Patients who underwent stereoelectroencephalography (SEEG) recording were included in this study. The SEEG data were visually inspected and quantitatively analyzed. The narrowband oscillations and aperiodic components at seizure onset were parameterized. The frequency-specific non-linear correlation analysis was applied to the functional connectivity. The excitation/inhibition ratio (E:I ratio) reflected by the aperiodic slope was performed to evaluate the excitability.

RESULTS

Twenty patients were included in the study, with 10 diagnosed with anterior cingulate epilepsy and 10 with anterior insular epilepsy. In both types of epilepsy, the correlation coefficient (h2 ) between the ACC and AIC at seizure onset exhibited a significantly higher value than that during interictal and preictal periods (p < 0.05). The direction index (D) showed a significant increase at seizure onset, serving as an indicator for the direction of information flow between these two brain regions with up to 90% accuracy. The E:I ratio increased significantly at seizure onset, with the seizure-onset zone (SOZ) demonstrating a more pronounced increase compared to non-SOZ (p < 0.05). For seizures originating from AIC, the E:I ratio was significantly higher in the AIC than in the ACC (p = 0.0364).

CONCLUSIONS

In the context of epilepsy, the ACC and AIC are dynamically coupled during seizures. The functional connectivity and excitability exhibit a significant increase at seizure onset. By analyzing connectivity and excitability, the SOZ in ACC and AIC can be identified. The direction index (D) serves as an indicator for the direction of information flow from SOZ to non-SOZ. Notably, the excitability of SOZ changes more significantly than that of non-SOZ.

The Pathogenesis of Disinhibition in Patients with Traumatic Brain Injury: A Two Patient Case Report

Higher brain dysfunction commonly occurs following traumatic brain injury (TBI), and may manifest in a social behavioral impairment which can significantly impede active social participation. We report two cases, one of voyeurism and the second of alcohol abuse, which might have been caused by TBI resulting in disinhibition, a type of social behavioral impairment. We discuss the underlying pathophysiological mechanisms to raise awareness of such cases and aid the development of effective interventions. Patient 1 suffered a TBI at 18 years of age, 2 years after which he presented repeated episodes of sexually deviant behavior (voyeurism). At 28, he committed suicide, since he was unable to control his aberrant behavior. Patient 2 suffered a TBI at the age of 13. He first displayed problematic behavior 7 years later, which included drinking excessive amounts of alcohol and stealing while inebriated. Despite both patients having sound moral judgment, they had irrational and uncontrollable impulses of desire. Imaging findings could explain the possible causes of impulse control impairments. Damage to the basal ganglia and limbic system, which are involved in social behavior, presumably led to desire-dominated behavior, leading to the patients conducting unlawful acts despite intact moral judgment. It is crucial to educate society about the prevalence of these disorders, explain how these disinhibitions start, and develop effective interventions.

Dissociated coupling between cerebral oxygen metabolism and perfusion in the prefrontal cortex during exercise: a NIRS study

Purpose: The present study used near-infrared spectroscopy to investigate the relationships between cerebral oxygen metabolism and perfusion in the prefrontal cortex (PFC) during exercises of different intensities. Methods: A total of 12 recreationally active men (age 24 ± 6 years) were enrolled. They performed 17 min of low-intensity exercise (ExL), followed by 3 min of moderate-intensity exercise (ExM) at constant loads. Exercise intensities for ExL and ExM corresponded to 30% and 45% of the participants' heart rate reserve, respectively. Cardiovascular and respiratory parameters were measured. We used near-infrared time-resolved spectroscopy (TRS) to measure the cerebral hemoglobin oxygen saturation (ScO2) and total hemoglobin concentration ([HbT]), which can indicate the cerebral blood volume (CBV). As the cerebral metabolic rate for oxygen (CMRO2) is calculated using cerebral blood flow (CBF) and ScO2, we assumed a constant power law relationship between CBF and CBV based on investigations by positron emission tomography (PET). We estimated the relative changes in CMRO2 (rCMRO2) and CBV (rCBV) from the baseline. During ExL and ExM, the rate of perceived exertion was monitored, and alterations in the subjects' mood induced by exercise were evaluated using the Profile of Moods Scale-Brief. Results: Three minutes after exercise initiation, ScO2 decreased and rCMRO2 surpassed rCBV in the left PFC. When ExL changed to ExM, cardiovascular variables and the sense of effort increased concomitantly with an increase in [HbT] but not in ScO2, and the relationship between rCMRO2 and rCBV was dissociated in both sides of the PFC. Immediately after ExM, [HbT], and ScO2 increased, and the disassociation between rCMRO2 and rCBV was prominent in both sides of the PFC. While blood pressure decreased and a negative mood state was less prominent following ExM compared with that at rest, ScO2 decreased 15 min after exercise and rCMRO2 surpassed rCBV in the left PFC. Conclusion: Dissociated coupling between cerebral oxidative metabolism and perfusion in the PFC was consistent with the effort required for increased exercise intensity and associated with post-exercise hypotension and altered mood status after exercise. Our result demonstrates the first preliminary results dealing with the coupling between cerebral oxidative metabolism and perfusion in the PFC using TRS.

Regional superficial amygdala resting-state functional connectivity in adults infers childhood maltreatment severity

Background

Childhood maltreatment (CM) is a potential risk factor for some neuropsychiatric disorders in adulthood (e.g. depression and anxiety) and alters trajectories of brain development. Accumulating evidence suggests that functional connectivity of the limbic system, especially the amygdala, is highly associated with childhood maltreatment, although not all studies have found this. These inconsistent results may be due to differential alterations of amygdala resting-state functional connectivity (rsFC) following childhood maltreatment.

Objective

Our aim was to investigate the relationship between the rsFC of amygdala subregions and CM severity, as well as to develop a stable rsFC-based model for inferring the severity of CM.

Methods

In this study, we employed the Childhood Trauma Questionnaire (CTQ) to assess CM severity in each individual. We explored the relationship between the rsFC of amygdala subregions (i.e. centromedial -CMA, basolateral -BLA, superficial-SFA amygdala) and CM experience in a discovery dataset of n = 110 healthy Chinese participants by linear multiple regression analysis. Subsequent dimensional and categorical approach were performed to elucidate the relationship between rsFCs and CM severity and CM subtypes, respectively. A support vector regression model was then conducted to validate the associations between rsFCs and total CTQ scores. Moreover, we also verified the model into another independent replication dataset (n = 38).

Results

Our findings suggested that childhood maltreatment was negatively associated with rsFC between the right superficial amygdala and perigenual anterior cingulate cortex (pgACC)/postcentral gyrus (PCG) but not the other two amygdala subregions. Moreover, SFA-pgACC coupling was more associated with physical neglect whereas the SFA-PCG was more related to emotional neglect. In addition, supervised machine learning confirmed that using these two rsFCs as predictors could stably estimate continuous maltreatment severity in both discovery and replication datasets.

Conclusion

The current study supports that the rsFCs of superficial amygdala are related to childhood maltreatment and which may be a potential biomarker for the effects of childhood maltreatment-related psychiatric disorders (i.e. depression and anxiety).

Sleep deprivation altered encoding of basolateral amygdala on fear acquisition

Sleep deprivation (SD) may lead to the development of fear- and anxiety-related emotional disorders. However, the neural mechanisms underlying the effects of SD on fear acquisition are unclear. Here, we tested whether and how SD influences the behavioral and neural manifestations of fear acquisition. We found that subjective fear ratings and objective fear indices (skin conductance response [SCR]) in the SD group were greater than those in the control group during fear acquisition, suggesting that SD facilitated fear acquisition (nSD = 18 and ncontrol = 23 for self-reported rating analysis; nSD = 10 and ncontrol = 10 for SCR analysis). Neuroimaging data showed that the SD group exhibited stronger activity in the left basolateral amygdala (BLA) and left superficial amygdala (SFA). Moreover, the left BLA activity, which positively correlated with the objective fear indices, significantly mediated the effect of SD on fear acquisition. Together, the present findings indicate that SD facilitates fear acquisition by augmenting threat-specific encoding in the BLA, which may be a potential biomarker of the risk of developing fear-related disorders under traumatic and distressing situations.

Associations of mTBI and post-traumatic stress to amygdala structure and functional connectivity in military Service Members

INTRODUCTION

Traumatic brain injury (TBI) is one of the highest public health priorities, especially among military personnel where comorbidity with post-traumatic stress symptoms and resulting consequences is high. Brain injury and post-traumatic stress symptoms are both characterized by dysfunctional brain networks, with the amygdala specifically implicated as a region with both structural and functional abnormalities.

METHODS

This study examined the structural volumetrics and resting state functional connectivity of 68 Active Duty Service Members with or without chronic mild TBI (mTBI) and comorbid symptoms of Post-Traumatic Stress (PTS).

RESULTS AND DISCUSSION

Structural analysis of the amygdala revealed no significant differences in volume between mTBI and healthy comparison participants with and without post-traumatic stress symptoms. Resting state functional connectivity with bilateral amygdala revealed decreased anterior network connectivity and increased posterior network connectivity in the mTBI group compared to the healthy comparison group. Within the mTBI group, there were significant regions of correlation with amygdala that were modulated by PTS severity, including networks implicated in emotional processing and executive functioning. An examination of a priori regions of amygdala connectivity in the default mode network, task positive network, and subcortical structures showed interacting influences of TBI and PTS, only between right amygdala and right putamen. These results suggest that mTBI and PTS are associated with hypo-frontal and hyper-posterior amygdala connectivity. Additionally, comorbidity of these conditions appears to compound these neural activity patterns. PTS in mTBI may change neural resource recruitment for information processing between the amygdala and other brain regions and networks, not only during emotional processing, but also at rest.

Prolonged Exposure to Cocaine Self-Administration Results in a Continued Progression of Alterations in Functional Activity in a Nonhuman Primate Model

Background

Studies of nonhuman primates with exposures of up to 100 days of cocaine self-administration (SA) have provided evidence that the central effects of cocaine progress over time. These durations of cocaine exposure, however, may be insufficient to capture the extent of the neurobiological alterations observed in cocaine users, many of whom use the drug for years. The goal of the present study was to determine whether 1.5 years of cocaine SA would result in further progression of alterations in functional brain activity.

Methods

Adult male rhesus monkeys were exposed to 300 sessions of high-dose cocaine SA over 1.5 years. Following the final session rates of local cerebral glucose utilization (LCGU) were assessed with the 2-[¹⁴C]-deoxyglucose method and compared to rates of LCGU in control monkeys who responded for food reinforcement. In addition, LCGU in these animals was compared to a previously published group of monkeys that had self-administered cocaine or food for 100 sessions over a 4-5 month period.

Results

Compared to 100 days of exposure, 300 days of cocaine SA further reduced LCGU in the post-commissural striatum and produced reductions in areas unaffected by the shorter duration of exposure, such as the hypothalamus, all of the amygdala, and large expanses of cortex.

Conclusions

These findings demonstrate a clear progression of the impact of cocaine on functional activity with increasing durations of drug experience and have important implications for the development of potential strategies for the treatment of cocaine use disorder.

The Aversive Lens: Stress effects on the prefrontal-cingulate cortical pathways that regulate emotion

ARNSTEN, A.F.T., M.K.P. Joyce and A.C. Roberts. The Aversive Lens: Stress effects on the prefrontal-cingulate cortical pathways that regulate emotion. NEUROSCI BIOBEHAV REV XXX-XXX, 2022. The symptoms of major-depressive-disorder include psychic pain and anhedonia, i.e. seeing the world through an "aversive lens". The neurobiology underlying this shift in worldview is emerging. Here these data are reviewed, focusing on how activation of subgenual cingulate (BA25) induces an "aversive lens", and how higher prefrontal cortical (PFC) areas (BA46/10/32) provide top-down regulation of BA25 but are weakened by excessive dopamine and norepinephrine release during stress exposure, and dendritic spine loss with chronic stress exposure. These changes may generate an attractor state, which maintains the brain under the control of BA25, requiring medication or neuromodulatory treatments to return connectivity to a more flexible state. In line with this hypothesis, effective anti-depressant treatments reduce the activity of BA25 and restore top-down regulation by higher circuits, e.g. as seen with SSRI medications, ketamine, deep brain stimulation of BA25, or rTMS to strengthen dorsolateral PFC. This research has special relevance in an era of chronic stress caused by the COVID19 pandemic, political unrest and threat of climate change.

Transanterior Limiting Sulcus of the Insula Approach: Novel Surgical Approach to the Ventral Striatum Region

BACKGROUND

Lesions in the ventral striatum region (above the anterior perforated substance) are a challenge for neurosurgeons due to their direct relationship with the lenticulostriate arteries, which difficult the surgical access. The standard approaches for this region include the following: 1) transfrontal approach, 2) transanterior perforating substance approach, 3) transcallosal transventricular approach, and 4) pterional transsylvian-transinsular route. In this study, we aimed to describe a novel anatomical approach through the anterior limiting sulcus of the insula in order to access the ventral striatum.

METHODS

We reviewed the literature and performed a detailed dissection of this region by using Klingler's technique with brain specimens injected with silicone, paying special attention to the white fibers and lenticulostriate arteries, and provided a description of an illustrative case of a cavernous malformation.

RESULTS

Neuroanatomical dissections showed that the lenticulostriate arteries had an inverted C-shaped anterior concavity, leaving less significant vascular relationships in the depth of the anterior limiting sulcus of the insula. In the case we described, the cavernous malformation was completely resected and the patient was discharged without any neurological deficits.

CONCLUSIONS

The transanterior limiting sulcus of the insula approach to the ventral striatum offers a safe access route for selected cases and can be performed on the basis of anatomical references. Three-dimensional understanding of the intrinsic brain architecture and its relationships with vascular structures in this specific area is important and can be acquired mainly through laboratory training.

Metabotropic glutamate receptors and cognition: From underlying plasticity and neuroprotection to cognitive disorders and therapeutic targets

Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors that play pivotal roles in mediating the activity of neurons and other cell types within the brain, communication between cell types, synaptic plasticity, and gene expression. As such, these receptors play an important role in a number of cognitive processes. In this chapter, we discuss the role of mGlu receptors in various forms of cognition and their underlying physiology, with an emphasis on cognitive dysfunction. Specifically, we highlight evidence that links mGlu physiology to cognitive dysfunction across brain disorders including Parkinson's disease, Alzheimer's disease, Fragile X syndrome, post-traumatic stress disorder, and schizophrenia. We also provide recent evidence demonstrating that mGlu receptors may elicit neuroprotective effects in particular disease states. Lastly, we discuss how mGlu receptors can be targeted utilizing positive and negative allosteric modulators as well as subtype specific agonists and antagonist to restore cognitive function across these disorders.

Characterization of Resting-State Striatal Differences in First-Episode Depression and Recurrent Depression

The presence of reward deficits in major depressive disorder is associated with abnormal striatal function. However, differences in striatal whole-brain functional between recurrent depressive episode (RDE) and first-episode depression (FDE) have not been elucidated. Thirty-three patients with RDE, 27 with FDE, and 35 healthy controls (HCs) were recruited for this study. A seed-based functional connectivity (FC) method was used to analyze abnormalities in six predefined striatal subregion circuits among the three groups of subjects and to further explore the correlation between abnormal FC and clinical symptoms. The results revealed that compared with the FDE group, the RDE group showed higher FC of the striatal subregion with the left middle occipital gyrus, left orbital area of the middle frontal gyrus, and bilateral posterior cerebellar gyrus, while showing lower FC of the striatal subregion with the right thalamus, left inferior parietal lobule, left middle cingulate gyrus, right angular gyrus, right cerebellum anterior lobe, and right caudate nucleus. In the RDE group, the HAMD-17 scores were positively correlated with the FC between the left dorsal rostral putamen and the left cerebellum posterior lobe. This study provides new insights into understanding the specificity of striatal circuits in the RDE group.

Neuropathology and neuroanatomy of TDP-43 amyotrophic lateral sclerosis

PURPOSE OF REVIEW

Intracellular inclusions consisting of the abnormal TDP-43 protein and its nucleocytoplasmic mislocalization in selected cell types are hallmark pathological features of sALS. Descriptive (histological, morphological), anatomical, and molecular studies all have improved our understanding of the neuropathology of sporadic amyotrophic lateral sclerosis (sALS). This review highlights some of the latest developments in the field.

RECENT FINDINGS

Increasing evidence exists from experimental models for the prion-like nature of abnormal TDP-43, including a strain-effect, and with the help of neuroimaging-based studies, for spreading of disease along corticofugal connectivities in sALS. Progress has also been made with respect to finding and establishing reliable biomarkers (neurofilament levels, diffusor tensor imaging).

SUMMARY

The latest findings may help to elucidate the preclinical phase of sALS and to define possible mechanisms for delaying or halting disease development and progression.

Single doses of a highly selective inhibitor of phosphodiesterase 1 (lenrispodun) in healthy volunteers: a randomized pharmaco-fMRI clinical trial

Lenrispodun is a potent and highly selective inhibitor of phosphodiesterase (PDE) type 1, which is thought to prolong intracellular second messenger signaling within cortical and subcortical dopaminergic brain regions. This is the first study of a PDE1 inhibitor in healthy volunteers using behavioral and neuroimaging approaches to examine its effects on neural targets and to provide a safety and tolerability assessment. The primary objectives were to determine whether lenrispodun induces changes in BOLD fMRI signals in the inferior frontal gyrus (IFG) during the stop signal task, and the dorsal anterior insula (dAI) during the extinction phase of a fear conditioning/extinction task. Using a double-blind, placebo-controlled, within-subjects design, 26 healthy individuals (22 completed all fMRI sessions) received in random order a single oral dose of placebo, lenrispodun 1.0 milligram (mg) or lenrispodun 10.0 mg and completed several tasks in the scanner including the stop signal (n = 24) and fear conditioning/extinction tasks (n = 22). Prespecified region-of-interest analyses for the IFG and dAI were computed using linear mixed models. Lenrispodun induced increases in IFG activity during the stop signal task at 1.0 mg (Cohen's d = 0.63) but not 10.0 mg (Cohen's d = 0.07) vs. placebo. Lenrispodun did not induce changes in dAI activity during fear extinction at either dose. Exploratory outcomes revealed changes in cardiac interoception. Lenrispodun administration was well-tolerated. These results provide evidence that 1.0 mg lenrispodun selectively improved neural inhibitory control without altering fear extinction processing. Future investigations should determine whether lenrispodun improves inhibitory control in target populations such as individuals with attention deficit hyperactivity disorder. Trial registration: ClinicalTrials.gov identifier: NCT03489772.

An exploratory study of resting-state functional connectivity of amygdala subregions in posttraumatic stress disorder following trauma in adulthood

We carried out an exploratory study aimed at identifying differences in resting-state functional connectivity for the amygdala and its subregions, right and left basolateral, centromedial and superficial nuclei, in patients with Posttraumatic Stress Disorder (PTSD), relative to controls. The study included 10 participants with PTSD following trauma in adulthood (9 females), and 10 controls (9 females). The results suggest PTSD was associated with a decreased (negative) functional connectivity between the superficial amygdala and posterior brain regions relative to controls. The differences were observed between right superficial amygdala and right fusiform gyrus, and between left superficial amygdala and left lingual and left middle occipital gyri. The results suggest that among PTSD patients, the worse the PTSD symptoms, the lower the connectivity. The results corroborate the fMRI literature that shows PTSD is associated with weaker amygdala functional connectivity with areas of the brain involved in sensory and perceptual processes. The results also suggest that though the patients traumatic experience occured in adulthood, the presence of early traumatic experiences were associated with negative connectivity between the centromedial amygdala and sensory and perceptual regions. We argue that the understanding of the mechanisms of PTSD symptoms, its behaviors and the effects on quality of life of patients may benefit from the investigation of brain function that underpins sensory and perceptual symptoms associated with the disorder.

Concurrent Structural and Functional Patterns in Patients With Amnestic Mild Cognitive Impairment

Amnestic mild cognitive impairment (aMCI) is a clinical subtype of MCI, which is known to have a high risk of developing Alzheimer's disease (AD). Although neuroimaging studies have reported brain abnormalities in patients with aMCI, concurrent structural and functional patterns in patients with aMCI were still unclear. In this study, we combined voxel-based morphometry (VBM), amplitude of low-frequency fluctuations (ALFFs), regional homogeneity (Reho), and resting-state functional connectivity (RSFC) approaches to explore concurrent structural and functional alterations in patients with aMCI. We found that, compared with healthy controls (HCs), both ALFF and Reho were decreased in the right superior frontal gyrus (SFG_R) and right middle frontal gyrus (MFG_R) of patients with aMCI, and both gray matter volume (GMV) and Reho were decreased in the left inferior frontal gyrus (IFG_L) of patients with aMCI. Furthermore, we took these overlapping clusters from VBM, ALFF, and Reho analyses as seed regions to analyze RSFC. We found that, compared with HCs, patients with aMCI had decreased RSFC between SFG_R and the right temporal lobe (subgyral) (TL_R), the MFG_R seed and left superior temporal gyrus (STG_L), left inferior parietal lobule (IPL_L), and right anterior cingulate cortex (ACC_R), the IFG_L seed and left precentral gyrus (PRG_L), left cingulate gyrus (CG_L), and IPL_L. These findings highlighted shared imaging features in structural and functional magnetic resonance imaging (MRI), suggesting that SFG_R, MFG_R, and IFG_L may play a major role in the pathophysiology of aMCI, which might be useful to better understand the underlying neural mechanisms of aMCI and AD.

An Action-Independent Role for Midfrontal Theta Activity Prior to Error Commission

Error-related electroencephalographic (EEG) signals have been widely studied concerning the human cognitive capability of differentiating between erroneous and correct actions. Midfrontal error-related negativity (ERN) and theta band oscillations are believed to underlie post-action error monitoring. However, it remains elusive how early monitoring activity is trackable and what are the pre-response brain mechanisms related to performance monitoring. Moreover, it is still unclear how task-specific parameters, such as cognitive demand or motor control, influence these processes. Here, we aimed to test pre- and post-error EEG patterns for different types of motor responses and investigate the neuronal mechanisms leading to erroneous actions. We implemented a go/no-go paradigm based on keypresses and saccades. Participants received an initial instruction about the direction of response to be given based on a facial cue and a subsequent one about the type of action to be performed based on an object cue. The paradigm was tested in 20 healthy volunteers combining EEG and eye tracking. We found significant differences in reaction time, number, and type of errors between the two actions. Saccadic responses reflected a higher number of premature responses and errors compared to the keypress ones. Nevertheless, both led to similar EEG patterns, supporting previous evidence for increased ERN amplitude and midfrontal theta power during error commission. Moreover, we found pre-error decreased theta activity independent of the type of action. Source analysis suggested different origin for such pre- and post-error neuronal patterns, matching the anterior insular cortex and the anterior cingulate cortex, respectively. This opposite pattern supports previous evidence of midfrontal theta not only as a neuronal marker of error commission but also as a predictor of action performance. Midfrontal theta, mostly associated with alert mechanisms triggering behavioral adjustments, also seems to reflect pre-response attentional mechanisms independently of the action to be performed. Our findings also add to the discussion regarding how salience network nodes interact during performance monitoring by suggesting that pre- and post-error patterns have different neuronal sources within this network.

Test-retest stability of spontaneous brain activity and functional connectivity in the core resting-state networks assessed with ultrahigh field 7-Tesla resting-state functional magnetic resonance imaging

The growing demand for precise and reliable biomarkers in psychiatry is fueling research interest in the hope that identifying quantifiable indicators will improve diagnoses and treatment planning across a range of mental health conditions. The individual properties of brain networks at rest have been highlighted as a possible source for such biomarkers, with the added advantage that they are relatively straightforward to obtain. However, an important prerequisite for their consideration is their reproducibility. While the reliability of resting‐state (RS) measurements has often been studied at standard field strengths, they have rarely been investigated using ultrahigh‐field (UHF) magnetic resonance imaging (MRI) systems. We investigated the intersession stability of four functional MRI RS parameters—amplitude of low‐frequency fluctuations (ALFF) and fractional ALFF (fALFF; representing the spontaneous brain activity), regional homogeneity (ReHo; measure of local connectivity), and degree centrality (DC; measure of long‐range connectivity)—in three RS networks, previously shown to play an important role in several psychiatric diseases—the default mode network (DMN), the central executive network (CEN), and the salience network (SN). Our investigation at individual subject space revealed a strong stability for ALFF, ReHo, and DC in all three networks, and a moderate level of stability in fALFF. Furthermore, the internetwork connectivity between each network pair was strongly stable between CEN/SN and moderately stable between DMN/SN and DMN/SN. The high degree of reliability and reproducibility in capturing the properties of the three major RS networks by means of UHF‐MRI points to its applicability as a potentially useful tool in the search for disease‐relevant biomarkers.

The Brain Is Adaptive Not Triune: How the Brain Responds to Threat, Challenge, and Change

Theory impacts how research is conducted. A popular theory used to conceptualize brain functioning is the triune brain theory. The triune brain theory is an evolutionary theory of brain development that emphasizes three key brain regions consisting of the brainstem, the limbic system, and the cortex that function relatively independently in coping with stress via fight or flight, emotion, and cognition, respectively. However, modern neuroscience research demonstrates that the triune brain theory does not accurately explain how the brain functions in everyday life or during the stress response. Specifically, emotion and cognition are interdependent and work together, the limbic system is not a purely emotional center nor are there purely emotional circuits in the brain, and the cortex is not a purely cognitive center nor are there purely cognitive circuits in the brain. We propose a new evolutionarily based model, the adaptive brain, that is founded on adaptive prediction resulting from interdependent brain networks using interoception and exteroception to balance current needs, and the interconnections among homeostasis, allostasis, emotion, cognition, and strong social bonds in accomplishing adaptive goals.

Amygdala function in emotion, cognition, and behavior

The amygdala is a core structure in the anterior medial temporal lobe, with an important role in several brain functions involving memory, emotion, perception, social cognition, and even awareness. As a key brain structure for saliency detection, it triggers and controls widespread modulatory signals onto multiple areas of the brain, with a great impact on numerous aspects of adaptive behavior. Here we discuss the neural mechanisms underlying these functions, as established by animal and human research, including insights provided in both healthy and pathological conditions.

Evolution of prefrontal cortex

Subdivisions of the prefrontal cortex (PFC) evolved at different times. Agranular parts of the PFC emerged in early mammals, and rodents, primates, and other modern mammals share them by inheritance. These are limbic areas and include the agranular orbital cortex and agranular medial frontal cortex (areas 24, 32, and 25). Rodent research provides valuable insights into the structure, functions, and development of these shared areas, but it contributes less to parts of the PFC that are specific to primates, namely, the granular, isocortical PFC that dominates the frontal lobe in humans. The first granular PFC areas evolved either in early primates or in the last common ancestor of primates and tree shrews. Additional granular PFC areas emerged in the primate stem lineage, as represented by modern strepsirrhines. Other granular PFC areas evolved in simians, the group that includes apes, humans, and monkeys. In general, PFC accreted new areas along a roughly posterior to anterior trajectory during primate evolution. A major expansion of the granular PFC occurred in humans in concert with other association areas, with modifications of corticocortical connectivity and gene expression, although current evidence does not support the addition of a large number of new, human-specific PFC areas.

A deep learning toolbox for automatic segmentation of subcortical limbic structures from MRI images

A tool was developed to automatically segment several subcortical limbic structures (nucleus accumbens, basal forebrain, septal nuclei, hypothalamus without mammillary bodies, the mammillary bodies, and fornix) using only a T1-weighted MRI as input. This tool fills an unmet need as there are few, if any, publicly available tools to segment these clinically relevant structures. A U-Net with spatial, intensity, contrast, and noise augmentation was trained using 39 manually labeled MRI data sets. In general, the Dice scores, true positive rates, false discovery rates, and manual-automatic volume correlation were very good relative to comparable tools for other structures. A diverse data set of 698 subjects were segmented using the tool; evaluation of the resulting labelings showed that the tool failed in less than 1% of cases. Test-retest reliability of the tool was excellent. The automatically segmented volume of all structures except mammillary bodies showed effectiveness at detecting either clinical AD effects, age effects, or both. This tool will be publicly released with FreeSurfer (surfer.nmr.mgh.harvard.edu/fswiki/ScLimbic). Together with the other cortical and subcortical limbic segmentations, this tool will allow FreeSurfer to provide a comprehensive view of the limbic system in an automated way.

Dynamic Functional Connectivity Reveals Abnormal Variability in the Amygdala Subregions of Children With Attention-Deficit/Hyperactivity Disorder

Objective: This study investigates whether the dynamic functional connectivity (dFC) of the amygdala subregions is altered in children with attention-deficit/hyperactivity disorder (ADHD).

Methods: The dFC of the amygdala subregions was systematically calculated using a sliding time window method, for 75 children with ADHD and 20 healthy control (HC) children.

Results: Compared with the HC group, the right superficial amygdala exhibited significantly higher dFC with the right prefrontal cortex, the left precuneus, and the left post-central gyrus for children in the ADHD group. The dFC of the amygdala subregions showed a negative association with the cognitive functions of children in the ADHD group.

Conclusion: Functional connectivity of the amygdala subregions is more unstable among children with ADHD. In demonstrating an association between the stability of functional connectivity of the amygdala and cognitive functions, this study may contribute by providing a new direction for investigating the internal mechanism of ADHD.

Identification of candidate genes on the basis of SNP by time-lagged heat stress interactions for milk production traits in German Holstein cattle

The aim of this study was to estimate genotype by time-lagged heat stress (HS) variance components as well as main and interaction SNP-marker effects for maternal HS during the last eight weeks of cow pregnancy, considering milk production traits recorded in the offspring generation. The HS indicator was the temperature humidity index (THI) for each week. A dummy variable with the code = 1 for the respective week for THI ≥ 60 indicated HS, otherwise, for no HS, the code = 0 was assigned. The dataset included test-day and lactation production traits from 14,188 genotyped first parity Holstein cows. After genotype quality control, 41,139 SNP markers remained for the genomic analyses. Genomic animal models without (model VC_nHS) and with in-utero HS effects (model VC_wHS) were applied to estimate variance components. Accordingly, for genome-wide associations, models GWA_nHS and GWA_wHS, respectively, were applied to estimate main and interaction SNP effects. Common genomic and residual variances for the same traits were very similar from models VC_nHS and VC_wHS. Genotype by HS interaction variances varied, depending on the week with in-utero HS. Among all traits, lactation milk yield with HS from week 5 displayed the largest proportion for interaction variances (0.07). For main effects from model GWA_wHS, 380 SNPs were suggestively associated with all production traits. For the SNP interaction effects from model GWA_wHS, we identified 31 suggestive SNPs, which were located in close distance to 62 potential candidate genes. The inferred candidate genes have various biological functions, including mechanisms of immune response, growth processes and disease resistance. Two biological processes excessively represented in the overrepresentation tests addressed lymphocyte and monocyte chemotaxis, ultimately affecting immune response. The modelling approach considering time-lagged genotype by HS interactions for production traits inferred physiological mechanisms being associated with health and immunity, enabling improvements in selection of robust animals.

The mouse cortico-basal ganglia-thalamic network

The cortico–basal ganglia–thalamo–cortical loop is one of the fundamental network motifs in the brain. Revealing its structural and functional organization is critical to understanding cognition, sensorimotor behaviour, and the natural history of many neurological and neuropsychiatric disorders. Classically, this network is conceptualized to contain three information channels: motor, limbic and associative^1–4. Yet this three-channel view cannot explain the myriad functions of the basal ganglia. We previously subdivided the dorsal striatum into 29 functional domains on the basis of the topography of inputs from the entire cortex⁵. Here we map the multi-synaptic output pathways of these striatal domains through the globus pallidus external part (GPe), substantia nigra reticular part (SNr), thalamic nuclei and cortex. Accordingly, we identify 14 SNr and 36 GPe domains and a direct cortico-SNr projection. The striatonigral direct pathway displays a greater convergence of striatal inputs than the more parallel striatopallidal indirect pathway, although direct and indirect pathways originating from the same striatal domain ultimately converge onto the same postsynaptic SNr neurons. Following the SNr outputs, we delineate six domains in the parafascicular and ventromedial thalamic nuclei. Subsequently, we identify six parallel cortico–basal ganglia–thalamic subnetworks that sequentially transduce specific subsets of cortical information through every elemental node of the cortico–basal ganglia–thalamic loop. Thalamic domains relay this output back to the originating corticostriatal neurons of each subnetwork in a bona fide closed loop.

Mesoscale connectomic mapping of the cortico–basal ganglia–thalamic network reveals key architectural and information processing features.

Altered Patterns of Amplitude of Low-Frequency Fluctuations and Fractional Amplitude of Low-Frequency Fluctuations Between Amnestic and Vascular Mild Cognitive Impairment: An ALE-Based Comparative Meta-Analysis

Background: Changes in the amplitude of low-frequency fluctuations (ALFF) and the fractional amplitude of low-frequency fluctuations (fALFF) have provided stronger evidence for the pathophysiology of cognitive impairment. Whether the altered patterns of ALFF and fALFF differ in amnestic cognitive impairment (aMCI) and vascular mild cognitive impairment (vMCI) is largely unknown. The purpose of this study was to explore the ALFF/fALFF changes in the two diseases and to further explore whether they contribute to the diagnosis and differentiation of these diseases.

Methods: We searched PubMed, Ovid, and Web of Science databases for articles on studies using the ALFF/fALFF method in patients with aMCI and vMCI. Based on the activation likelihood estimation (ALE) method, connectivity modeling based on coordinate meta-analysis and functional meta-analysis was carried out.

Results: Compared with healthy controls (HCs), patients with aMCI showed increased ALFF/fALFF in the bilateral parahippocampal gyrus/hippocampus (PHG/HG), right amygdala, right cerebellum anterior lobe (CAL), left middle temporal gyrus (MTG), left cerebrum temporal lobe sub-gyral, left inferior temporal gyrus (ITG), and left cerebrum limbic lobe uncus. Meanwhile, decreased ALFF/fALFF values were also revealed in the bilateral precuneus (PCUN), bilateral cuneus (CUN), and bilateral posterior cingulate (PC) in patients with aMCI. Compared with HCs, patients with vMCI predominantly showed decreased ALFF/fALFF in the bilateral CUN, left PCUN, left PC, and right cingulate gyrus (CG).

Conclusions: The present findings suggest that ALFF and fALFF displayed remarkable altered patterns between aMCI and vMCI when compared with HCs. Thus, the findings of this study may serve as a reliable tool for distinguishing aMCI from vMCI, which may help understand the pathophysiological mechanisms of these diseases.

Impact of prenatal stress on amygdala anatomy in young adulthood: Timing and location matter

BACKGROUND

Exposure to maternal stress in utero has long-term implications for the developing brain and has been linked with a higher risk of depression. The amygdala, which develops during the early embryonic stage and is critical for emotion processing, might be particularly sensitive.

METHODS

Using data from a neuroimaging follow-up of the ELSPAC prenatal birth cohort (n=129, 47% men, 23-24 years old), we studied the impact of prenatal stress during the first and second half of pregnancy on the volume of the amygdala and its nuclei in young adult offspring. We further evaluated the relationship between amygdala anatomy and offspring depressive symptomatology. Amygdala nuclei were parcellated using FreeSurfer's automated segmentation pipeline. Depressive symptoms were measured via self-report using the Beck Depression Inventory (BDI).

RESULTS

Exposure to stress during the first half of pregnancy was associated with smaller accessory basal (Cohen's f²=0.27, p(FDR)=0.03) and cortical (Cohen's f²=0.29, p(FDR)=0.03) nuclei volumes. This effect remained significant after correcting for sex, stress during the second half of pregnancy, as well as maternal age at birth, birth weight, maternal education, and offspring's age at MRI. These two nuclei showed a quadratic relationship with BDI scores in young adulthood, where both smaller and larger volume was associated with more depressive symptoms (Accessory basal nucleus: Adj R²=0.05. p(FDR)=0.015; Cortical nucleus: Adj R²=0.04, p(FDR)=0.015).

CONCLUSIONS

We conclude that exposure to stress during the first half of pregnancy might have long-term implications for amygdala anatomy, which may in turn predict the experience of depressive symptoms in young adulthood.

Patrolling the boundaries of social domains: Neural activations to violations of expectations for romantic and work relationships

According to the social domains hypothesis, we reduce the information-processing demands of complex social cues by classifying them into a limited number of domains, each with distinct sets of expectations. This requires rapid identification of violations of the boundaries between social domains. We hypothesized that these violations are likely to be associated with neural activation of the salience system. Using fMRI we compared responses of 20 adults to expected and unexpected everyday social scenarios in personal and work interactions. The vignettes exemplified different kinds of scenarios presented in the work setting, i.e., task-focused scenarios which are expected at work and scenarios with a personal focus, which are unexpected at work. The key contrast between task and personal focussed scenarios presented in the work setting was associated with fronto-insular activation. Perceived inappropriateness of the unexpected scenarios, and shorter response time to judgment of inappropriateness were also associated with fronto-insular activation, after controlling for unpleasantness. This study indicates specific neural responses to violations of expectations in different social situations. Our findings suggest that the fronto-insular region is implicated in rapid detection of behaviors that cross the boundaries of social domains, which are hypothesized to be necessary for efficient social information processing.

The basal ganglia and the cerebellum in human emotion

The basal ganglia (BG) and the cerebellum historically have been relegated to a functional role in producing or modulating motor output. Recent research, however, has emphasized the importance of these subcortical structures in multiple functional domains, including affective processes such as emotion recognition, subjective feeling elicitation and reward valuation. The pathways through the thalamus that connect the BG and cerebellum directly to each other and with extensive regions of the cortex provide a structural basis for their combined influence on limbic function. By regulating cortical oscillations to guide learning and strengthening rewarded behaviors or thought patterns to achieve a desired goal state, these regions can shape the way an individual processes emotional stimuli. This review will discuss the basic structure and function of the BG and cerebellum and propose an updated view of their functional role in human affective processing.

Activating Corticotropin-Releasing Factor Systems in the Nucleus Accumbens, Amygdala, and Bed Nucleus of Stria Terminalis: Incentive Motivation or Aversive Motivation?

BACKGROUND

Corticotropin-releasing factor (CRF) neural systems are important stress mechanisms in the central amygdala (CeA), bed nucleus of stria terminalis (BNST), nucleus accumbens (NAc), and related structures. CRF-containing neural systems are traditionally posited to generate aversive distress states that motivate overconsumption of rewards and relapse in addiction. However, CRF-containing systems may alternatively promote incentive motivation to increase reward pursuit and consumption without requiring aversive states.

METHODS

We optogenetically stimulated CRF-expressing neurons in the CeA, BNST, or NAc using Crh-Cre+ rats (n = 37 female, n = 34 male) to investigate roles in incentive motivation versus aversive motivation. We paired CRF-expressing neuronal stimulations with earning sucrose rewards in two-choice and progressive ratio tasks and investigated recruitment of distributed limbic circuitry. We further assessed valence with CRF-containing neuron laser self-stimulation tasks.

RESULTS

Channelrhodopsin excitation of CRF-containing neurons in the CeA and NAc amplified and focused incentive motivation and recruited activation of mesocorticolimbic reward circuitry. CRF systems in both the CeA and NAc supported laser self-stimulation, amplified incentive motivation for sucrose in a breakpoint test, and focused "wanting" on laser-paired sucrose over a sucrose alternative in a two-choice test. Conversely, stimulation of CRF-containing neurons in the BNST produced negative valence or aversive effects and recruited distress-related circuitry, as stimulation was avoided and suppressed motivation for sucrose.

CONCLUSIONS

CRF-containing systems in the NAc and CeA can promote reward consumption by increasing incentive motivation without involving aversion. In contrast, stimulation of CRF-containing systems in the BNST is aversive but suppresses sucrose reward pursuit and consumption rather than increase, as predicted by traditional hedonic self-medication hypotheses.

Corticolimbic Circuitry in Chronic Pain Tracks Pain Intensity Relief Following Exposure In Vivo

Background

A subset of patients with chronic pain who receive exposure in vivo (EXP) treatment experience clinically relevant relief of pain intensity. Although pain relief is not an explicit therapeutic target, it is important to understand how and why this concomitant effect occurs in some patients but not others. This longitudinal study therefore aimed to characterize brain plasticity as well as to explore pretreatment factors related to pain relief.

Methods

Resting-state functional magnetic resonance imaging data were acquired in 30 patients with chronic pain. Twenty-three patients completed EXP, and 6-month follow-up data were available in 20 patients (magnetic resonance imaging data in 17 patients). Pain-free control data were acquired at two time points (n = 29, n = 21). Seed-based resting-state functional connectivity (rsFC) analyses were performed, with seeds in the amygdala, hippocampus, and nucleus accumbens.

Results

Pain relief after EXP was highly variable, with 60% of patients reporting a clinically relevant improvement. Amygdala rsFC with the middle frontal gyrus decreased significantly over time in patients but was not associated with pain relief. In contrast, greater pain relief was associated with greater decreases over time in hippocampus rsFC with the precuneus, which was related to reductions in catastrophizing (EXP therapeutic target) as well. Greater pain relief was also associated with lower pretreatment rsFC between nucleus accumbens and postcentral gyrus.

Conclusions

While changes in hippocampus rsFC were associated with pain relief after EXP, pretreatment nucleus accumbens rsFC showed potential prognostic value. Our findings further support the importance of corticolimbic circuitry in chronic pain, emphasizing its relation to pain relief and identifying potential underlying mechanisms and prognostic factors, warranting further testing in independent samples.

Extended-amygdala intrinsic functional connectivity networks: A population study

Pre-clinical and human neuroimaging research implicates the extended-amygdala (ExtA) (including the bed nucleus of the stria terminalis [BST] and central nucleus of the amygdala [CeA]) in networks mediating negative emotional states associated with stress and substance-use behaviours. The extent to which individual ExtA structures form a functionally integrated unit is controversial. We utilised a large sample (n > 1,000 healthy young adult humans) to compare the intrinsic functional connectivity networks (ICNs) of the BST and CeA using task-free functional magnetic resonance imaging (fMRI) data from the Human Connectome Project. We assessed whether inter-individual differences within these ICNs were related to two principal components representing negative disposition and alcohol use. Building on recent primate evidence, we tested whether within BST-CeA intrinsic functional connectivity (iFC) was heritable and further examined co-heritability with our principal components. We demonstrate the BST and CeA to have discrete, but largely overlapping ICNs similar to previous findings. We found no evidence that within BST-CeA iFC was heritable; however, post hoc analyses found significant BST iFC heritability with the broader superficial and centromedial amygdala regions. There were no significant correlations or co-heritability associations with our principal components either across the ICNs or for specific BST-Amygdala iFC. Possible differences in phenotype associations across task-free, task-based, and clinical fMRI are discussed, along with suggestions for more causal investigative paradigms that make use of the now well-established ExtA ICNs.

Common and Specific Alterations of Amygdala Subregions in Major Depressive Disorder With and Without Anxiety: A Combined Structural and Resting-State Functional MRI Study

Anxious major depressive disorder is a common subtype of major depressive disorder; however, its unique neural mechanism is not well-understood currently. Using multimodal MRI data, this study examined common and specific alterations of amygdala subregions between patients with and without anxiety. No alterations were observed in the gray matter volume or intra-region functional integration in either patient group. Compared with the controls, both patient groups showed decreased functional connectivity between the left superficial amygdala and the left putamen, and between the right superficial amygdala and the bilateral anterior cingulate cortex and medial orbitofrontal cortex, while only patients with anxiety exhibited decreased activity in the bilateral laterobasal and superficial amygdala. Moreover, the decreased activity correlated negatively with the Hamilton depression scale scores in the patients with anxiety. These findings provided insights into the pathophysiologic processes of anxious major depressive disorder and may help to develop new and effective treatment programs.

Microsurgical anatomy of the amygdaloid body and its connections

The amygdaloid body is a limbic nuclear complex characterized by connections with the thalamus, the brainstem and the neocortex. The recent advances in functional neurosurgery regarding the treatment of refractory epilepsy and several neuropsychiatric disorders renewed the interest in the study of its functional Neuroanatomy. In this scenario, we felt that a morphological study focused on the amygdaloid body and its connections could improve the understanding of the possible  implications in functional neurosurgery. With this purpose we performed a morfological study using nine formalin-fixed human hemispheres dissected under microscopic magnification by using the fiber dissection technique originally described by Klingler. In our results the  amygdaloid body presents two divergent projection systems named dorsal and ventral amygdalofugal pathways connecting the nuclear complex with the septum and the hypothalamus. Furthermore, the amygdaloid body is connected with the hippocampus through the amygdalo-hippocampal bundle, with the anterolateral temporal cortex through the amygdalo-temporalis fascicle, the anterior commissure and the temporo-pulvinar bundle of Arnold, with the insular cortex through the lateral olfactory stria, with the ambiens gyrus, the para-hippocampal gyrus and the basal forebrain through the cingulum, and with the frontal cortex through the uncinate fascicle. Finally, the amygdaloid body is connected with the brainstem through the medial forebrain bundle. Our description of the topographic anatomy of the amygdaloid body and its connections, hopefully represents a useful tool for clinicians and scientists, both in the scope of application and speculation.

Analysis of brain functional response to cutaneous prickling stimulation by single fiber

BACKGROUND

It is now well understood that, as an uncomfortable sensation evoked by special fabric, prickle derives from the mechanical stimulation of protruding hairiness from fabric surface against the human skin, in which some nociceptors are easy to be triggered by stiff fiber ends. However, up to now, the neural mechanism of the brain for perceiving fabric-evoked prickle is still unclear.

MATERIALS AND METHODS

In this work, A type of single-fiber stimulus made from nylon filament was used to repetitively prick the skin of volar forearm at a specific frequency, and the technology of functional magnetic resonance imaging (fMRI) was adopted to detect the brain response synchronously.

RESULTS

The results show that repetitive prickling stimulation from the single fiber applied to the volar forearm aroused distributed activation in several brain regions, such as primary somatosensory cortex, secondary somatosensory cortex, motor cortex, bilateral occipital lobe, insular cortex, and ipsilateral limbic lobe. Although the brain activation distribution is similar to pain, the single fiber-evoked prickle sensation possesses unique activation characteristics in several brain regions.

CONCLUSION

It is suggested that the sensation evoked by cutaneous prickling stimulation from single fiber belongs to a kind of multidimensional experience involving somatosensory, motor, emotional, cognitive, etc Our study constitutes an important step toward identifying the brain mechanism of fabric-evoked prickle.

Enhanced functional connectivity between insular subregions correlates with the efficacy of music and instruction-guided relaxation in depression

Music and instruction-guided relaxation (MIGR) is a complementary therapeutic tool used in the treatment of the major depressive disorder (MDD). However, the neural mechanism that underlies the effect of MIGR on MDD patients is not known. Twenty-three right-handed MDD patients and 23 age-, sex-, handedness-, and educational level-matched healthy controls were enrolled. Resting-state functional MRI data were acquired from patients before and after MIGR and from healthy controls. The relationships between insular subregion-based functional connectivity and Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale (HAM-A), Automatic Thoughts Questionnaire, and Ruminative Responses Scale scores were examined. One-way analysis of variance exhibited significant differences among the three groups in functional connectivity between the left dorsal anterior insula (dAI) and left superior medial frontal gyrus (SMFG), left dAI and left precuneus, left posterior insula and left gyrus rectus, right ventral anterior insula (vAI) and left posterior cingulate cortex (PCC), right vAI and right inferior frontal gyrus (R-IFG). Further comparisons in regions of interest showed that MDD patients before MIGR showed decreased functional connectivity between the left dAI and left SMFG, left dAI and left precuneus, left posterior insula, and left gyrus rectus, right vAI and left PCC, right vAI and R-IFG relative to those in healthy controls. The strength of functional connectivity between the right dAI and left putamen also exhibited a negative correlation with the HAM-A score in MDD cases before MIGR. MIGR may result in enhanced functional connectivity in insular subregions, thereby potentially increasing the regulatory influence of cognitive reappraisal.

Pre-Brodmann pioneers of cortical cytoarchitectonics I: Theodor Meynert, Vladimir Betz and William Bevan-Lewis

This study and the sequel paper revisit landmark discoveries that paved the way to the definition of the renowned Brodmann areas in the human cerebral cortex, in an attempt to rectify certain undeserved historical neglects. A 'first period of discoveries,' from 1867 to 1882, is represented by the work of neuropsychiatrists Theodor Meynert (1833-1892) in Vienna, Vladimir Betz (1834-1894) in Kiev and William Bevan-Lewis (1847-1929) in Wakefield. Their classical findings are placed in a modern perspective.

Altered amygdala-based functional connectivity in individuals with attenuated psychosis syndrome and first-episode schizophrenia

Altered resting-state functional connectivity (FC) of the amygdala (AMY) has been demonstrated to be implicated in schizophrenia (SZ) and attenuated psychosis syndrome (APS). Specifically, no prior work has investigated FC in individuals with APS using subregions of the AMY as seed regions of interest. The present study examined AMY subregion-based FC in individuals with APS and first-episode schizophrenia (FES) and healthy controls (HCs). The resting state FC maps of the three AMY subregions were computed and compared across the three groups. Correlation analysis was also performed to examine the relationship between the Z-values of regions showing significant group differences and symptom rating scores. Individuals with APS showed hyperconnectivity between the right centromedial AMY (CMA) and left frontal pole cortex (FPC) and between the laterobasal AMY and brain stem and right inferior lateral occipital cortex compared to HCs. Patients with FES showed hyperconnectivity between the right superficial AMY and left occipital pole cortex and between the left CMA and left thalamus compared to the APS and HCs respectively. A negative relationship was observed between the connectivity strength of the CMA with the FPC and negative-others score of the Brief Core Schema Scales in the APS group. We observed different altered FC with subregions of the AMY in individuals with APS and FES compared to HCs. These results shed light on the pathogenetic mechanisms underpinning the development of APS and SZ.

Integrity of Amygdala Subregion-Based Functional Networks and Emotional Lability in Drug-Naïve Boys With ADHD

Objective: This study evaluated the functional networks of amygdala subregions (basolateral [BLA], centromedial [CMA], and superficial amygdala [SFA]) in ADHD and their association with emotional lability (EL) symptoms. Method: Resting-state functional connectivity (RSFC) of amygdala subregions and their correlations with EL scores were evaluated in 35 drug-naïve boys with ADHD and 30 age-matched healthy controls (HC). Results: Compared with HC, altered RSFC were detected differently for each amygdala subregion in ADHD: altered RSFC of BLA with the thalamus and vermis; aberrant RSFC of CMA with the superior temporal gyrus/pole and insula, precuneus and cerebellum; reduced RSFC of SFA with dorsal frontoparietal cortices. Within ADHD, higher EL scores were associated with reduced negative RSFC of SFA with the dorsolateral prefrontal cortex and inferior parietal lobe. Conclusion: Diffuse alterations of amygdala subregion-based networks are associated with ADHD, and the weaker SFA-frontoparietal networks might be involved in the hypothesized top-down effortful regulation of emotion.

Dynamics of the Sphere Model of Consciousness: Silence, Space, and Self

The Sphere Model of Consciousness (SMC) delineates a sphere-shaped matrix that aims to describe subjective experiences using geometric coordinates, in accordance with a neurophenomenological perspective. According to the SMC, an experience of overcoming the habitual self and the conditioning of memories could be placed at the center of the matrix, which can then be called the Place of Pre-Existence (PPE). The PPE is causally associated with self-determination. In this context, we suggest that silence could be considered an intentional inner environment enabling self-perception to focus on the “here and now,” which in turn improves perception of one’s own body in space. To investigate the hypotheses grounded in the model, the current preliminary study examined the Place of Pre-Existence Technique (PPEt), in which practitioners are guided to focus on a self-defined aim, reach a state of detachment from the habitual self, and envision the future. Four-hundred eighty-one volunteer PPEt practitioners completed self-report questionnaires before and after an intensive 3-day meditative training. We analyzed potential relationships between subjective experiences related to physical, emotional, mental, temporal, and spatial components, as well as self-determination and silence, before and after training. The results indicated a transition from a prevailing influence of mental dimension on the other aspects of experience, to a prevailing influence of the spatial dimension. Silence was reported more often following the training and was predominantly related to mental and emotional experiences. The results are discussed in the framework of the SMC, as compared to other models, and in relation to the shift from Narrative to Minimal Self and to increased balance among the considered dimensions.

Multidimensional processing in the amygdala

Brain-wide circuits that coordinate affective and social behaviours intersect in the amygdala. Consequently, amygdala lesions cause a heterogeneous array of social and non-social deficits. Social behaviours are not localized to subdivisions of the amygdala even though the inputs and outputs that carry social signals are anatomically restricted to distinct subnuclear regions. This observation may be explained by the multidimensional response properties of the component neurons. Indeed, the multitudes of circuits that converge in the amygdala enlist the same subset of neurons into different ensembles that combine social and non-social elements into high-dimensional representations. These representations may enable flexible, context-dependent social decisions. As such, multidimensional processing may operate in parallel with subcircuits of genetically identical neurons that serve specialized and functionally dissociable functions. When combined, the activity of specialized circuits may grant specificity to social behaviours, whereas multidimensional processing facilitates the flexibility and nuance needed for complex social behaviour.