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Hassani S, Neumann A, Russell J, Jones C, Womelsdorf T. M 1-selective muscarinic allosteric modulation enhances cognitive flexibility and effective salience in nonhuman primates. Proc Natl Acad Sci U S A 2023; 120:e2216792120. [PMID: 37104474 PMCID: PMC10161096 DOI: 10.1073/pnas.2216792120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 03/21/2023] [Indexed: 04/28/2023] Open
Abstract
Acetylcholine (ACh) in cortical neural circuits mediates how selective attention is sustained in the presence of distractors and how flexible cognition adjusts to changing task demands. The cognitive domains of attention and cognitive flexibility might be differentially supported by the M1 muscarinic acetylcholine receptor (mAChR) subtype. Understanding how M1 mAChR mechanisms support these cognitive subdomains is of highest importance for advancing novel drug treatments for conditions with altered attention and reduced cognitive control including Alzheimer's disease or schizophrenia. Here, we tested this question by assessing how the subtype-selective M1 mAChR positive allosteric modulator (PAM) VU0453595 affects visual search and flexible reward learning in nonhuman primates. We found that allosteric potentiation of M1 mAChRs enhanced flexible learning performance by improving extradimensional set shifting, reducing latent inhibition from previously experienced distractors and reducing response perseveration in the absence of adverse side effects. These procognitive effects occurred in the absence of apparent changes of attentional performance during visual search. In contrast, nonselective ACh modulation using the acetylcholinesterase inhibitor (AChEI) donepezil improved attention during visual search at doses that did not alter cognitive flexibility and that already triggered gastrointestinal cholinergic side effects. These findings illustrate that M1 mAChR positive allosteric modulation enhances cognitive flexibility without affecting attentional filtering of distraction, consistent with M1 activity boosting the effective salience of relevant over irrelevant objects specifically during learning. These results suggest that M1 PAMs are versatile compounds for enhancing cognitive flexibility in disorders spanning schizophrenia and Alzheimer's diseases.
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Affiliation(s)
- Seyed A. Hassani
- Department of Psychology, Vanderbilt University, Nashville, TN37240
| | - Adam Neumann
- Department of Psychology, Vanderbilt University, Nashville, TN37240
| | - Jason Russell
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN37240
| | - Carrie K. Jones
- Department of Pharmacology, Vanderbilt University, Nashville, TN37240
- Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN37240
| | - Thilo Womelsdorf
- Department of Psychology, Vanderbilt University, Nashville, TN37240
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN37240
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2
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Berry AS, Harrison TM. New perspectives on the basal forebrain cholinergic system in Alzheimer's disease. Neurosci Biobehav Rev 2023; 150:105192. [PMID: 37086935 DOI: 10.1016/j.neubiorev.2023.105192] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/27/2023] [Accepted: 03/28/2023] [Indexed: 04/24/2023]
Abstract
The basal forebrain cholinergic system (BFCS) has long been implicated in age-related cognitive changes and the pathophysiology of Alzheimer's disease (AD). Limitations of cholinergic interventions helped to inspire a shift away from BFCS in AD research. A resurgence in interest in the BFCS following methodological and analytical advances has resulted in a call for the BFCS to be examined in novel frameworks. We outline the basic structure and function of the BFCS, its role in supporting cognitive and affective function, and its vulnerability to aging and AD. We consider the BFCS in the context of the amyloid hypothesis and evolving concepts in AD research: resilience and resistance to pathology, selective neuronal vulnerability, trans-synaptic pathology spread and sleep health. We highlight 1) the potential role of the BFCS in cognitive resilience, 2) recent work refining understanding about the selective vulnerability of BFCS to AD, 3) BFCS connectivity that suggests it is related to tau spreading and neurodegeneration and 4) the gap between BFCS involvement in AD and sleep-wake cycles.
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Affiliation(s)
- Anne S Berry
- Brandeis University, Waltham, Massachusetts, 02453.
| | - Theresa M Harrison
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California, 94720
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3
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Basal Forebrain Chemogenetic Inhibition Converts the Attentional Control Mode of Goal-Trackers to That of Sign-Trackers. eNeuro 2022; 9:ENEURO.0418-22.2022. [PMID: 36635246 PMCID: PMC9794377 DOI: 10.1523/eneuro.0418-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/06/2022] [Accepted: 11/29/2022] [Indexed: 12/14/2022] Open
Abstract
Sign tracking versus goal tracking in rats indicate vulnerability and resistance, respectively, to Pavlovian cue-evoked addictive drug taking and relapse. Here, we tested hypotheses predicting that the opponent cognitive-behavioral styles indexed by sign tracking versus goal tracking include variations in attentional performance which differentially depend on basal forebrain projection systems. Pavlovian Conditioned Approach (PCA) testing was used to identify male and female sign-trackers (STs) and goal-trackers (GTs), as well as rats with an intermediate phenotype (INTs). Upon reaching asymptotic performance in an operant task requiring the detection of visual signals (hits) as well as the reporting of signal absence for 40 min per session, GTs scored more hits than STs, and hit rates across all phenotypes correlated with PCA scores. STs missed relatively more signals than GTs specifically during the last 15 min of a session. Chemogenetic inhibition of the basal forebrain decreased hit rates in GTs but was without effect in STs. Moreover, the decrease in hits in GTs manifested solely during the last 15 min of a session. Transfection efficacy in the horizontal limb of the diagonal band (HDB), but not substantia innominate (SI) or nucleus basalis of Meynert (nbM), predicted the behavioral efficacy of chemogenetic inhibition in GTs. Furthermore, the total subregional transfection space, not transfection of just cholinergic neurons, correlated with performance effects. These results indicate that the cognitive-behavioral phenotype indexed by goal tracking, but not sign tracking, depends on activation of the basal forebrain-frontal cortical projection system and associated biases toward top-down or model-based performance.
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4
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Liu F, Zhao R. Enhancing spiking neural networks with hybrid top-down attention. Front Neurosci 2022; 16:949142. [PMID: 36071719 PMCID: PMC9443487 DOI: 10.3389/fnins.2022.949142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
As the representatives of brain-inspired models at the neuronal level, spiking neural networks (SNNs) have shown great promise in processing spatiotemporal information with intrinsic temporal dynamics. SNNs are expected to further improve their robustness and computing efficiency by introducing top-down attention at the architectural level, which is crucial for the human brain to support advanced intelligence. However, this attempt encounters difficulties in optimizing the attention in SNNs largely due to the lack of annotations. Here, we develop a hybrid network model with a top-down attention mechanism (HTDA) by incorporating an artificial neural network (ANN) to generate attention maps based on the features extracted by a feedforward SNN. The attention map is then used to modulate the encoding layer of the SNN so that it focuses on the most informative sensory input. To facilitate direct learning of attention maps and avoid labor-intensive annotations, we propose a general principle and a corresponding weakly-supervised objective, which promotes the HTDA model to utilize an integral and small subset of the input to give accurate predictions. On this basis, the ANN and the SNN can be jointly optimized by surrogate gradient descent in an end-to-end manner. We comprehensively evaluated the HTDA model on object recognition tasks, which demonstrates strong robustness to adversarial noise, high computing efficiency, and good interpretability. On the widely-adopted CIFAR-10, CIFAR-100, and MNIST benchmarks, the HTDA model reduces firing rates by up to 50% and improves adversarial robustness by up to 10% with comparable or better accuracy compared with the state-of-the-art SNNs. The HTDA model is also verified on dynamic neuromorphic datasets and achieves consistent improvements. This study provides a new way to boost the performance of SNNs by employing a hybrid top-down attention mechanism.
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5
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Donovan E, Avila C, Klausner S, Parikh V, Fenollar-Ferrer C, Blakely RD, Sarter M. Disrupted Choline Clearance and Sustained Acetylcholine Release In Vivo by a Common Choline Transporter Coding Variant Associated with Poor Attentional Control in Humans. J Neurosci 2022; 42:3426-3444. [PMID: 35232764 PMCID: PMC9034784 DOI: 10.1523/jneurosci.1334-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Transport of choline via the neuronal high-affinity choline transporter (CHT; SLC5A7) is essential for cholinergic terminals to synthesize and release acetylcholine (ACh). In humans, we previously demonstrated an association between a common CHT coding substitution (rs1013940; Ile89Val) and reduced attentional control as well as attenuated frontal cortex activation. Here, we used a CRISPR/Cas9 approach to generate mice expressing the I89V substitution and assessed, in vivo, CHT-mediated choline transport, and ACh release. Relative to wild-type (WT) mice, CHT-mediated clearance of choline in male and female mice expressing one or two Val89 alleles was reduced by over 80% in cortex and over 50% in striatum. Choline clearance in CHT Val89 mice was further reduced by neuronal inactivation. Deficits in ACh release, 5 and 10 min after repeated depolarization at a low, behaviorally relevant frequency, support an attenuated reloading capacity of cholinergic neurons in mutant mice. The density of CHTs in total synaptosomal lysates and neuronal plasma-membrane-enriched fractions was not impacted by the Val89 variant, indicating a selective impact on CHT function. When challenged with a visual disruptor to reveal attentional control mechanisms, Val89 mice failed to adopt a more conservative response bias. Structural modeling revealed that Val89 may attenuate choline transport by altering conformational changes of CHT that support normal transport rates. Our findings support the view that diminished sustained cholinergic signaling capacity underlies perturbed attentional performance in individuals expressing CHT Val89. The CHT Val89 mouse serves as a valuable model to study heritable risk for cognitive disorders arising from cholinergic dysfunction.SIGNIFICANCE STATEMENT Acetylcholine (ACh) signaling depends on the functional capacity of the neuronal choline transporter (CHT). Previous research demonstrated that humans expressing the common CHT coding variant Val89 exhibit attentional vulnerabilities and attenuated fronto-cortical activation during attention. Here, we find that mice engineered to express the Val89 variant exhibit reduced CHT-mediated choline clearance and a diminished capacity to sustain ACh release. Additionally, Val89 mice lack cognitive flexibility in response to an attentional challenge. These findings provide a mechanistic and cognitive framework for interpreting the attentional phenotype associated with the human Val89 variant and establish a model that permits a more invasive interrogation of CNS effects as well as the development of therapeutic strategies for those, including Val89 carriers, with presynaptic cholinergic perturbations.
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Affiliation(s)
- Eryn Donovan
- Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109
| | - Cassandra Avila
- Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109
| | - Sarah Klausner
- Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109
| | - Vinay Parikh
- Department of Psychology & Neuroscience Program, Temple University, Philadelphia, Pennsylvania 19122
| | - Cristina Fenollar-Ferrer
- Laboratory of Molecular Genetics, Section of Human Genetics, National Institute on Deafness and Other Communication Disorders, Bethesda, Maryland 20892
| | - Randy D Blakely
- Stiles-Nicholson Brain Institute and Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, Florida 33458
| | - Martin Sarter
- Department of Psychology, Neuroscience Program and Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
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6
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Liu W, Li J, Yang M, Ke X, Dai Y, Lin H, Wang S, Chen L, Tao J. Chemical genetic activation of the cholinergic basal forebrain hippocampal circuit rescues memory loss in Alzheimer's disease. Alzheimers Res Ther 2022; 14:53. [PMID: 35418161 PMCID: PMC9006585 DOI: 10.1186/s13195-022-00994-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/27/2022] [Indexed: 11/18/2022]
Abstract
Background The degeneration of the cholinergic circuit from the basal forebrain to the hippocampus contributes to memory loss in patients suffering from Alzheimer’s disease (AD). However, the internal relationships between the acetylcholine (Ach) cycle and memory decline during the early stages of AD currently remain unknown. Here, we investigate the mechanisms underlying the activation of the cholinergic circuit and its impact on learning and memory using APP/PS1 mice models. Methods Novel object recognition and Morris water maze tests were used to measure learning and memory function. Magnetic resonance spectrum (MRS) imaging was applied to longitudinally track changes in neurochemical metabolism in APP/PS1 mice aged 2, 4, 6, and 8 months. The number of neurons and the deposition of Aβ plaques were measured using Nissl, immunohistochemistry, and Thioflavin S staining. We then employed a chemogenetic strategy to selectively activate the cholinergic circuit from the medial septal nucleus (MS) and the vertical limb of the diagonal band nucleus (VDB) on the basal forebrain to the hippocampus. MRS and immunoblotting techniques were used to measure the neurochemical metabolism levels and cholinergic-related proteins, respectively. Results We found that the levels of choline (Cho) in the basal forebrain were markedly higher compared to other brain regions and that its decrease along with N-acetyl aspartate (NAA) levels in the hippocampus was accompanied by memory deficits in APP/PS1 mice aged 4, 6, and 8 months. In terms of pathology, we observed that the deposition of Aβ plaques gradually aggravated throughout the cerebral cortex and hippocampus in APP/PS1 mice aged 6 and 8 months, while no Aβ deposition was detected in the basal forebrain. In contrast, the activity of choline acetyltransferase (ChAT) enzyme in the basal forebrain was decreased at 6 months of age and the cholinergic neurons were lost in the basal forebrain at 8 months of age. In addition, the activation of the cholinergic circuit from the MS and VDB to the hippocampus using chemical genetics is able to improve learning and reduce memory impairment in APP/PS1 mice. Similarly, the levels of Cho in the basal forebrain; NAA in the hippocampus, as well as the expression of ChAT and vesicular acetylcholine transporter (vAchT) in the basal forebrain; and muscarinic acetylcholine receptor 2 (CHRM2) in the hippocampus all increased. Conclusions These findings demonstrate that the neurochemical Cho and NAA of the cholinergic circuit can be used as biomarkers to enable the early diagnosis of AD. In addition, memory impairment in APP/PS1 mice can be attenuated using chemical genetics-driven Ach cycle activity of the cholinergic circuit. Supplementary Information The online version contains supplementary material available at 10.1186/s13195-022-00994-w.
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Affiliation(s)
- Weilin Liu
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,The Academy of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Jianhong Li
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Minguang Yang
- The Academy of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Xiaohua Ke
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Yaling Dai
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Huawei Lin
- Rehabilitation Medical Technology Joint National Local Engineering Research Center, Fuzhou, 350122, Fujian, China
| | - Sinuo Wang
- Rehabilitation Medical Technology Joint National Local Engineering Research Center, Fuzhou, 350122, Fujian, China
| | - Lidian Chen
- The Academy of Rehabilitation Industry, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China
| | - Jing Tao
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.
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7
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Hassani SA, Lendor S, Neumann A, Sinha Roy K, Banaie Boroujeni K, Hoffman KL, Pawliszyn J, Womelsdorf T. Dose-Dependent Dissociation of Pro-cognitive Effects of Donepezil on Attention and Cognitive Flexibility in Rhesus Monkeys. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 3:68-77. [PMID: 36712561 PMCID: PMC9874073 DOI: 10.1016/j.bpsgos.2021.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 02/01/2023] Open
Abstract
Background Donepezil exerts pro-cognitive effects by nonselectively enhancing acetylcholine (ACh) across multiple brain systems. Two brain systems that mediate pro-cognitive effects of attentional control and cognitive flexibility are the prefrontal cortex and the anterior striatum, which have different pharmacokinetic sensitivities to ACh modulation. We speculated that these area-specific ACh profiles lead to distinct optimal dose ranges for donepezil to enhance the cognitive domains of attention and flexible learning. Methods To test for dose-specific effects of donepezil on different cognitive domains, we devised a multitask paradigm for nonhuman primates that assessed attention and cognitive flexibility. The nonhuman primates received either vehicle or variable doses of donepezil before task performance. We measured intracerebral donepezil and its strength in preventing the breakdown of ACh within the prefrontal cortex and anterior striatum using solid phase microextraction neurochemistry. Results The highest administered donepezil dose improved attention and made the subjects more robust against distractor interference, but it did not improve flexible learning. In contrast, only a lower dose range of donepezil improved flexible learning and reduced perseveration, but without distractor-dependent attentional improvement. Neurochemical measurements confirmed a dose-dependent increase of extracellular donepezil and decreases in choline within the prefrontal cortex and the striatum. Conclusions The donepezil dose for maximally improving attention differed from the dose range that enhanced cognitive flexibility despite the availability of the drug in two major brain systems supporting these functions. These results suggest that in our cohort of adult monkeys, donepezil traded improvements in attention for improvements in cognitive flexibility at a given dose range.
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Affiliation(s)
- Seyed A. Hassani
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Sofia Lendor
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
| | - Adam Neumann
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Kanchan Sinha Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Kari L. Hoffman
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Janusz Pawliszyn
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada,Janusz Pawliszyn, Ph.D.
| | - Thilo Womelsdorf
- Department of Psychology, Vanderbilt University, Nashville, Tennessee,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee,Address correspondence to Thilo Womelsdorf, Ph.D.
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8
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Angelyn H, Loney GC, Meyer PJ. Nicotine Enhances Goal-Tracking in Ethanol and Food Pavlovian Conditioned Approach Paradigms. Front Neurosci 2021; 15:561766. [PMID: 34483813 PMCID: PMC8416423 DOI: 10.3389/fnins.2021.561766] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
Rationale Nicotine promotes alcohol intake through pharmacological and behavioral interactions. As an example of the latter, nicotine can facilitate approach toward food- and alcohol-associated stimuli ("sign-tracking") in lever-Pavlovian conditioned approach (PavCA) paradigms. However, we recently reported that nicotine can also enhance approach toward locations of reward delivery ("goal-tracking") triggered by ethanol-predictive stimuli when the location of ethanol delivery is non-static (i.e., a retractable sipper bottle). Objective To determine whether the non-static nature of the reward location could have biased the development of goal-tracking in our previous study (Loney et al., 2019); we assessed the effect of nicotine in a lever-PavCA paradigm wherein the location of ethanol delivery was static (i.e., a stationary liquid receptacle). Then, to determine whether nicotine's enhancement of goal-tracking is unique to ethanol-predictive stimuli, we assessed the effect of systemic nicotine on approach triggered by food-predictive stimuli in a lever-PavCA paradigm. Methods Long-Evans rats were used in two PavCA experiments wherein a lever predicted the receipt of ethanol (15% vol/vol; experiment 1) or food (experiment 2) into a stationary receptacle. Prior to testing, rats were administered nicotine (0.4 mg/kg subcutaneously) or saline systemically. Results In both experiments, nicotine increased measures of goal-tracking, but not sign-tracking. Conclusion Nicotine can facilitate approach to reward locations without facilitating approach to reward-predictive stimuli. As such, conceptualization of the mechanisms by which nicotine affects behavior must be expanded to explain an enhancement of goal-tracking by nicotine.
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Affiliation(s)
- Hailley Angelyn
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Gregory C Loney
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Paul J Meyer
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States
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9
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Riedel G, Klein J, Niewiadomska G, Kondak C, Schwab K, Lauer D, Magbagbeolu M, Steczkowska M, Zadrozny M, Wydrych M, Cranston A, Melis V, Santos RX, Theuring F, Harrington CR, Wischik CM. Mechanisms of Anticholinesterase Interference with Tau Aggregation Inhibitor Activity in a Tau-Transgenic Mouse Model. Curr Alzheimer Res 2021; 17:285-296. [PMID: 32091331 PMCID: PMC7403648 DOI: 10.2174/1567205017666200224120926] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/08/2020] [Accepted: 02/12/2020] [Indexed: 01/18/2023]
Abstract
Background Symptomatic treatments of Alzheimer’s Disease (AD) with cholinesterase inhibitors and/or memantine are relatively ineffective and there is a need for new treatments targeting the underlying pathology of AD. In most of the failed disease-modifying trials, patients have been allowed to continue taking symptomatic treatments at stable doses, under the assumption that they do not impair efficacy. In recently completed Phase 3 trials testing the tau aggregation inhibitor leuco-methylthioninium bis (hydromethane-sulfonate) (LMTM), we found significant differences in treatment response according to whether patients were taking LMTM either as monotherapy or as an add-on to symptomatic treatments. Methods We have examined the effect of either LMTM alone or chronic rivastigmine prior to LMTM treatment of tau transgenic mice expressing the short tau fragment that constitutes the tangle filaments of AD. We have measured acetylcholine levels, synaptosomal glutamate release, synaptic proteins, mitochondrial complex IV activity, tau pathology and Choline Acetyltransferase (ChAT) immunoreactivity. Results LMTM given alone increased hippocampal Acetylcholine (ACh) levels, glutamate release from synaptosomal preparations, synaptophysin levels in multiple brain regions and mitochondrial complex IV activity, reduced tau pathology, partially restored ChAT immunoreactivity in the basal forebrain and reversed deficits in spatial learning. Chronic pretreatment with rivastigmine was found to reduce or eliminate almost all these effects, apart from a reduction in tau aggregation pathology. LMTM effects on hippocampal ACh and synaptophysin levels were also reduced in wild-type mice. Conclusion The interference with the pharmacological activity of LMTM by a cholinesterase inhibitor can be reproduced in a tau transgenic mouse model and, to a lesser extent, in wild-type mice. Long-term pretreatment with a symptomatic drug alters a broad range of brain responses to LMTM across different transmitter systems and cellular compartments at multiple levels of brain function. There is, therefore, no single locus for the negative interaction. Rather, the chronic neuronal activation induced by reducing cholinesterase function produces compensatory homeostatic downregulation in multiple neuronal systems. This reduces a broad range of treatment responses to LMTM associated with a reduction in tau aggregation pathology. Since the interference is dictated by homeostatic responses to prior symptomatic treatment, it is likely that there would be similar interference with other drugs tested as add-on to the existing symptomatic treatment, regardless of the intended therapeutic target or mode of action. The present findings outline key results that now provide a working model to explain interference by symptomatic treatment.
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Affiliation(s)
- Gernot Riedel
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - Jochen Klein
- Department of Pharmacology and Clinical Pharmacy, Goethe University, Max-von-Laue Str. 9, Frankfurt, 60438 Frankfurt am Main, Germany
| | - Grazyna Niewiadomska
- Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Constantin Kondak
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom.,Department of Pharmacology and Clinical Pharmacy, Goethe University, Max-von-Laue Str. 9, Frankfurt, 60438 Frankfurt am Main, Germany
| | - Karima Schwab
- Charite-Institute of Pharmacology, Universitätsmedizin Berlin, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Dilyara Lauer
- Charite-Institute of Pharmacology, Universitätsmedizin Berlin, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Mandy Magbagbeolu
- Charite-Institute of Pharmacology, Universitätsmedizin Berlin, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Marta Steczkowska
- Mossakowski Medical Research Centre, 5 Pawinski Street, 02-106 Warsaw, Poland
| | - Maciej Zadrozny
- Mossakowski Medical Research Centre, 5 Pawinski Street, 02-106 Warsaw, Poland
| | - Malgorzata Wydrych
- Mossakowski Medical Research Centre, 5 Pawinski Street, 02-106 Warsaw, Poland
| | - Anna Cranston
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - Valeria Melis
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - Renato X Santos
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - Franz Theuring
- Charite-Institute of Pharmacology, Universitätsmedizin Berlin, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Charles R Harrington
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom.,TauRx Therapeutics Ltd., 395 King Street, Aberdeen AB24 5RP, United Kingdom
| | - Claude M Wischik
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom.,TauRx Therapeutics Ltd., 395 King Street, Aberdeen AB24 5RP, United Kingdom
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10
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Lockhofen DEL, Mulert C. Neurochemistry of Visual Attention. Front Neurosci 2021; 15:643597. [PMID: 34025339 PMCID: PMC8133366 DOI: 10.3389/fnins.2021.643597] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/12/2021] [Indexed: 11/25/2022] Open
Abstract
Visual attention is the cognitive process that mediates the selection of important information from the environment. This selection is usually controlled by bottom-up and top-down attentional biasing. Since for most humans vision is the dominant sense, visual attention is critically important for higher-order cognitive functions and related deficits are a core symptom of many neuropsychiatric and neurological disorders. Here, we summarize the importance and relative contributions of different neuromodulators and neurotransmitters to the neural mechanisms of top-down and bottom-up attentional control. We will not only review the roles of widely accepted neuromodulators, such as acetylcholine, dopamine and noradrenaline, but also the contributions of other modulatory substances. In doing so, we hope to shed some light on the current understanding of the role of neurochemistry in shaping neuron properties contributing to the allocation of attention in the visual field.
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Affiliation(s)
| | - Christoph Mulert
- Center for Psychiatry and Psychotherapy, Justus-Liebig University, Hessen, Germany
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11
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Sarter M, Avila C, Kucinski A, Donovan E. Make a Left Turn: Cortico-Striatal Circuitry Mediating the Attentional Control of Complex Movements. Mov Disord 2021; 36:535-546. [PMID: 33615556 DOI: 10.1002/mds.28532] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND In movement disorders such as Parkinson's disease (PD), cholinergic signaling is disrupted by the loss of basal forebrain cholinergic neurons, as well as aberrant activity in striatal cholinergic interneurons (ChIs). Several lines of evidence suggest that gait imbalance, a key disabling symptom of PD, may be driven by alterations in high-level frontal cortical and cortico-striatal processing more typically associated with cognitive dysfunction. METHODS Here we describe the corticostriatal circuitry that mediates the cognitive-motor interactions underlying such complex movement control. The ability to navigate dynamic, obstacle-rich environments requires the continuous integration of information about the environment with movement selection and sequencing. The cortical-attentional processing of extero- and interoceptive cues requires modulation by cholinergic activity to guide striatal movement control. Cue-derived information is "transferred" to striatal circuitry primarily via fronto-striatal glutamatergic projections. RESULT Evidence from parkinsonian fallers and from a rodent model reproducing the dual cholinergic-dopaminergic losses observed in these patients supports the main hypotheses derived from this neuronal circuitry-guided conceptualization of parkinsonian falls. Furthermore, in the striatum, ChIs constitute a particularly critical node for the integration of cortical with midbrain dopaminergic afferents and thus for cues to control movements. CONCLUSION Procholinergic treatments that enhance or rescue cortical and striatal mechanisms may improve complex movement control in parkinsonian fallers and perhaps also in older persons suffering from gait disorders and a propensity for falls. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Martin Sarter
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Cassandra Avila
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Aaron Kucinski
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Eryn Donovan
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA
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12
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Ojiakor O, Rylett R. Modulation of sodium-coupled choline transporter CHT function in health and disease. Neurochem Int 2020; 140:104810. [DOI: 10.1016/j.neuint.2020.104810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/16/2020] [Accepted: 07/09/2020] [Indexed: 12/27/2022]
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13
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Forebrain Cholinergic Signaling: Wired and Phasic, Not Tonic, and Causing Behavior. J Neurosci 2020; 40:712-719. [PMID: 31969489 DOI: 10.1523/jneurosci.1305-19.2019] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/29/2019] [Accepted: 11/04/2019] [Indexed: 01/21/2023] Open
Abstract
Conceptualizations of cholinergic signaling as primarily spatially diffuse and slow-acting are based largely on measures of extracellular brain ACh levels that require several minutes to generate a single data point. In addition, most such studies inhibited the highly potent catalytic enzyme for ACh, AChE, to facilitate measurement of ACh. Absent such inhibition, AChE limits the presence of ambient ACh and thus renders it unlikely that ACh influences target regions via slow changes in extracellular ACh concentrations. We describe an alternative view by which forebrain signaling in cortex driving cognition is largely phasic (milliseconds to perhaps seconds), and unlikely to be volume-transmitted. This alternative is supported by new evidence from real-time amperometric recordings of cholinergic signaling indicating a specific function of rapid, phasic, transient cholinergic signaling in attentional contexts. Previous neurochemical evidence may be reinterpreted in terms of integrated phasic cholinergic activity that mediates specific behavioral and cognitive operations; this reinterpretation fits well with recent computational models. Optogenetic studies support a causal relationship between cholinergic transients and behavior. This occurs in part via transient-evoked muscarinic receptor-mediated high-frequency oscillations in cortical regions. Such oscillations outlast cholinergic transients and thus link transient ACh signaling with more sustained postsynaptic activity patterns to support relatively persistent attentional biases. Reconceptualizing cholinergic function as spatially specific, phasic, and modulating specific cognitive operations is theoretically powerful and may lead to pharmacologic treatments more effective than those based on traditional views.Dual Perspectives Companion Paper: Diverse Spatiotemporal Scales of Cholinergic Signaling in the Neocortex, by Anita A. Disney and Michael J. Higley.
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14
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Complex Movement Control in a Rat Model of Parkinsonian Falls: Bidirectional Control by Striatal Cholinergic Interneurons. J Neurosci 2020; 40:6049-6067. [PMID: 32554512 DOI: 10.1523/jneurosci.0220-20.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/10/2020] [Accepted: 05/15/2020] [Indexed: 01/18/2023] Open
Abstract
Older persons and, more severely, persons with Parkinson's disease (PD) exhibit gait dysfunction, postural instability and a propensity for falls. These dopamine (DA) replacement-resistant symptoms are associated with losses of basal forebrain and striatal cholinergic neurons, suggesting that falls reflect disruption of the corticostriatal transfer of movement-related cues and their striatal integration with movement sequencing. To advance a rodent model of the complex movement deficits of Parkinsonian fallers, here we first demonstrated that male and female rats with dual cortical cholinergic and striatal DA losses (DL rats) exhibit cued turning deficits, modeling the turning deficits seen in these patients. As striatal cholinergic interneurons (ChIs) are positioned to integrate movement cues with gait, and as ChI loss has been associated with falls in PD, we next used this task, as well as a previously established task used to reveal heightened fall rates in DL rats, to broadly test the role of ChIs. Chemogenetic inhibition of ChIs in otherwise intact male and female rats caused cued turning deficits and elevated fall rates. Spontaneous turning was unaffected. Furthermore, chemogenetic stimulation of ChIs in DL rats reduced fall rates and restored cued turning performance. Stimulation of ChIs was relatively more effective in rats with viral transfection spaces situated lateral to the DA depletion areas in the dorsomedial striatum. These results indicate that striatal ChIs are essential for the control of complex movements, and they suggest a therapeutic potential of stimulation of ChIs to restore gait and balance, and to prevent falls in PD.SIGNIFICANCE STATEMENT In persons with Parkinson's disease, gait dysfunction and the associated risk for falls do not benefit from dopamine replacement therapy and often result in long-term hospitalization and nursing home placement. Here, we first validated a new task to demonstrate impairments in cued turning behavior in rodents modeling the cholinergic-dopaminergic losses observed in Parkinsonian fallers. We then demonstrated the essential role of striatal cholinergic interneurons for turning behavior as well as for traversing dynamic surfaces and avoiding falls. Stimulation of these interneurons in the rat model rescued turning performance and reduced fall rates. Our findings indicate the feasibility of investigating the neuronal circuitry underling complex movement control in rodents, and that striatal cholinergic interneurons are an essential node of such circuitry.
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15
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Richardson BD, Sottile SY, Caspary DM. Mechanisms of GABAergic and cholinergic neurotransmission in auditory thalamus: Impact of aging. Hear Res 2020; 402:108003. [PMID: 32703637 DOI: 10.1016/j.heares.2020.108003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/15/2020] [Accepted: 05/23/2020] [Indexed: 12/18/2022]
Abstract
Age-related hearing loss is a complex disorder affecting a majority of the elderly population. As people age, speech understanding becomes a challenge especially in complex acoustic settings and negatively impacts the ability to accurately analyze the auditory scene. This is in part due to an inability to focus auditory attention on a particular stimulus source while simultaneously filtering out other sound stimuli. The present review examines the impact of aging on two neurotransmitter systems involved in accurate temporal processing and auditory gating in auditory thalamus (medial geniculate body; MGB), a critical brain region involved in the coding and filtering of auditory information. The inhibitory neurotransmitter GABA and its synaptic receptors (GABAARs) are key to maintaining accurate temporal coding of complex sounds, such as speech, throughout the central auditory system. In the MGB, synaptic and extrasynaptic GABAARs mediate fast phasic and slow tonic inhibition respectively, which in turn regulate MGB neuron excitability, firing modes, and engage thalamocortical oscillations that shape coding and gating of acoustic content. Acoustic coding properties of MGB neurons are further modulated through activation of tegmental cholinergic afferents that project to MGB to potentially modulate attention and help to disambiguate difficult to understand or novel sounds. Acetylcholine is released onto MGB neurons and presynaptic terminals in MGB activating neuronal nicotinic and muscarinic acetylcholine receptors (nAChRs, mAChRs) at a subset of MGB afferents to optimize top-down and bottom-up information flow. Both GABAergic and cholinergic neurotransmission is significantly altered with aging and this review will detail how age-related changes in these circuits within the MGB may impact coding of acoustic stimuli.
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Affiliation(s)
- B D Richardson
- WWAMI Medical Education, University of Idaho, Moscow, ID, 83844, USA; Biological Engineering, University of Idaho, Moscow, ID, 83844, USA
| | - S Y Sottile
- Center for Clinical Research Southern Illinois University - School of Medicine, Springfield, IL, 62702, USA
| | - D M Caspary
- Department of Pharmacology Southern Illinois University - School of Medicine, Springfield, IL, 62702, USA.
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Azimi M, Oemisch M, Womelsdorf T. Dissociation of nicotinic α7 and α4/β2 sub-receptor agonists for enhancing learning and attentional filtering in nonhuman primates. Psychopharmacology (Berl) 2020; 237:997-1010. [PMID: 31865424 DOI: 10.1007/s00213-019-05430-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 12/11/2019] [Indexed: 12/22/2022]
Abstract
RATIONALE Nicotinic acetylcholine receptors (nAChRs) modulate attention, memory, and higher executive functioning, but it is unclear how nACh sub-receptors mediate different mechanisms supporting these functions. OBJECTIVES We investigated whether selective agonists for the alpha-7 nAChR versus the alpha-4/beta-2 nAChR have unique functional contributions for value learning and attentional filtering of distractors in the nonhuman primate. METHODS Two adult rhesus macaque monkeys performed reversal learning following systemic administration of either the alpha-7 nAChR agonist PHA-543613 or the alpha-4/beta-2 nAChR agonist ABT-089 or a vehicle control. Behavioral analysis quantified performance accuracy, speed of processing, reversal learning speed, the control of distractor interference, perseveration tendencies, and motivation. RESULTS We found that the alpha-7 nAChR agonist PHA-543613 enhanced the learning speed of feature values but did not modulate how salient distracting information was filtered from ongoing choice processes. In contrast, the selective alpha-4/beta-2 nAChR agonist ABT-089 did not affect learning speed but reduced distractibility. This dissociation was dose-dependent and evident in the absence of systematic changes in overall performance, reward intake, motivation to perform the task, perseveration tendencies, or reaction times. CONCLUSIONS These results suggest nicotinic sub-receptor specific mechanisms consistent with (1) alpha-4/beta-2 nAChR specific amplification of cholinergic transients in prefrontal cortex linked to enhanced cue detection in light of interferences, and (2) alpha-7 nAChR specific activation prolonging cholinergic transients, which could facilitate subjects to follow-through with newly established attentional strategies when outcome contingencies change. These insights will be critical for developing function-specific drugs alleviating attention and learning deficits in neuro-psychiatric diseases.
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Affiliation(s)
- Marzyeh Azimi
- Department of Biology, Centre for Vision Research, York University, Toronto, Ontario, M6J 1P3, Canada
| | - Mariann Oemisch
- Department of Biology, Centre for Vision Research, York University, Toronto, Ontario, M6J 1P3, Canada.,The Zanvyl Krieger Mind/Brain Institute, Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Thilo Womelsdorf
- Department of Biology, Centre for Vision Research, York University, Toronto, Ontario, M6J 1P3, Canada. .,Department of Psychology, Vanderbilt University, PMB 407817, 2301, Vanderbilt Place, Nashville, TN, 37240-7817, USA.
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17
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Phillips KB, Sarter M. Addiction vulnerability and the processing of significant cues: Sign-, but not goal-, tracker perceptual sensitivity relies on cue salience. Behav Neurosci 2020; 134:133-143. [PMID: 31916796 DOI: 10.1037/bne0000353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The identification of broadly defined psychological traits that bestow vulnerability for the manifestation of addiction-like behaviors can guide the discovery of the neuronal mechanisms underlying the propensity for drug taking. Sign-tracking behavior in rats (STs) signifies the presence of a trait that predicts a relatively greater behavioral control of Pavlovian drug and reward cues than in rats that exhibit goal-tracking behavior (GTs). We previously demonstrated that relatively poor cholinergic-attentional control in STs is an essential component of the trait indexed by sign-tracking and that this trait aspect contributes to the relatively greater power of drug cues to control the behavior of STs. Here we addressed the possibility that STs and GTs employ fundamentally different psychological mechanisms for the detection of cues in attention-demanding contexts. Rats were trained to perform an operant Sustained Attention Task. As task training advanced to the stage that taxed attentional control, the relative brightness of visual target signals significantly influenced detection performance in STs but not GTs. This finding suggests that STs, but not GTs, rely on bottom-up, cue salience-driven mechanisms to detect cues. GTs may be able to resist behavioral control by Pavlovian drug cues by utilizing goal-directed decisional processes that minimize the influence of the salience of drug cues. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
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18
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Rescuing the attentional performance of rats with cholinergic losses by the M1 positive allosteric modulator TAK-071. Psychopharmacology (Berl) 2020; 237:137-153. [PMID: 31620809 DOI: 10.1007/s00213-019-05354-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023]
Abstract
RATIONALE Loss of basal forebrain cholinergic neurons contributes to the severity of the cognitive decline in age-related dementia and, in patients with Parkinson's disease (PD), to impairments in gait and balance and the resulting risks for falls. Contrasting with the extensive evidence indicating an essential role of cholinergic activity in mediating cognitive, specifically attentional abilities, treatment with conventional acetylcholinesterase inhibitors (AChEIs) has not fulfilled the promise of efficacy of pro-cholinergic treatments. OBJECTIVES Here, we investigated the potential usefulness of a muscarinic M1 positive allosteric modulator (PAM) in an animal model of cholinergic loss-induced impairments in attentional performance. Given evidence indicating that fast, transient cholinergic signaling mediates the detection of cues in attentional contexts, we hypothesized that a M1 PAM amplifies such transient signaling and thereby rescues attentional performance. RESULTS Rats performed an operant sustained attention task (SAT), including in the presence of a distractor (dSAT) and during a post-distractor (post-dSAT) period. The post-dSAT period served to assess the capacity for recovering performance following a disruptive event. Basal forebrain infusions of the cholino-specific immunotoxin 192 IgG-saporin impaired SAT performance, and greater cholinergic losses predicted lower post-dSAT performance. Administration of TAK-071 (0.1, 0.3 mg/kg, p.o., administered over 6-day blocks) improved the performance of all rats during the post-dSAT period (main effect of dose). Drug-induced improvement of post-dSAT performance was relatively greater in lesioned rats, irrespective of sex, but also manifested in female control rats. TAK-071 primarily improved perceptual sensitivity (d') in lesioned rats and facilitated the adoption of a more liberal response bias (B˝D) in all female rats. CONCLUSIONS These findings suggest that TAK-071 may benefit the attentional performance of patients with partial cholinergic losses and specifically in situations that tax top-down, or goal-driven, attentional control.
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19
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Koshy Cherian A, Kucinski A, Wu R, de Jong IEM, Sarter M. Co-treatment with rivastigmine and idalopirdine reduces the propensity for falls in a rat model of falls in Parkinson's disease. Psychopharmacology (Berl) 2019; 236:1701-1715. [PMID: 30607479 DOI: 10.1007/s00213-018-5150-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 12/11/2018] [Indexed: 11/24/2022]
Abstract
RATIONALE Falls in patients with Parkinson's disease (PD) are associated with cognitive, specifically attentional impairments and with losses in cholinergic projection systems. We previously established an animal model of the combined basal forebrain cholinergic-striatal dopaminergic losses of PD fallers (Dual Lesioned, DL, rats) and demonstrated that treating DL rats with an acetylcholinesterase inhibitor (AChEI), donepezil, together with a 5HT6 receptor antagonist, idalopirdine, reduced fall frequency and improved associated aspects of the performance of DL rats traversing rotating rods. OBJECTIVES Here, we employed a longer and more taxing rotating beam apparatus to determine the potential therapeutic efficacy of idalopirdine when combined with the pseudo-irreversible, and thus relatively long-acting, AChE- and butyrylcholinesterase- (BuChE) inhibitor rivastigmine. RESULTS As before, vehicle-treated DL rats fell more frequently, committed more slips, and exhibited more movement stoppages than intact control rats. Repeated intermittent administration of rivastigmine and idalopirdine significantly improved the performance of DL rats. Rivastigmine alone also produced strong trends for reducing falls and slips. The combination treatment was more effective than rivastigmine alone in reducing stoppages and stoppage-associated falls. As before, idalopirdine treatment alone was ineffective. CONCLUSIONS These results extend the prediction that the combined treatment with idalopirdine and an AChEI improves complex movement control and reduces the propensity for falls in patients with movement disorders. Because of the importance of finding better treatments for gait and balance deficits in PD, the present results may further motivate a clinical exploration of the usefulness of this combination treatment.
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Affiliation(s)
- Ajeesh Koshy Cherian
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109, USA
| | - Aaron Kucinski
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109, USA
| | - Ryan Wu
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109, USA
| | | | - Martin Sarter
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109, USA.
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Shine JM. Neuromodulatory Influences on Integration and Segregation in the Brain. Trends Cogn Sci 2019; 23:572-583. [PMID: 31076192 DOI: 10.1016/j.tics.2019.04.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 12/20/2022]
Abstract
Cognitive function relies on the dynamic cooperation of specialized regions of the brain; however, the elements of the system responsible for coordinating this interaction remain poorly understood. In this Opinion article I argue that this capacity is mediated in part by competitive and cooperative dynamic interactions between two prominent metabotropic neuromodulatory systems - the cholinergic basal forebrain and the noradrenergic locus coeruleus (LC). I assert that activity in these projection nuclei regulates the amount of segregation and integration within the whole brain network by modulating the activity of a diverse set of specialized regions of the brain on a timescale relevant for cognition and attention.
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Affiliation(s)
- James M Shine
- Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia.
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21
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Koshy Cherian A, Tronson NC, Parikh V, Kucinski A, Blakely RD, Sarter M. Repetitive mild concussion in subjects with a vulnerable cholinergic system: Lasting cholinergic-attentional impairments in CHT+/- mice. Behav Neurosci 2019; 133:448-459. [PMID: 30896190 DOI: 10.1037/bne0000310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Previous research emphasized the impact of traumatic brain injury on cholinergic systems and associated cognitive functions. Here we addressed the converse question: Because of the available evidence indicating cognitive and neuronal vulnerabilities in humans expressing low-capacity cholinergic systems or with declining cholinergic systems, do injuries cause more severe cognitive decline in such subjects, and what cholinergic mechanisms contribute to such vulnerability? Using mice heterozygous for the choline transporter (CHT+/- mice) as a model for a limited cholinergic capacity, we investigated the cognitive and neuronal consequences of repeated, mild concussion injuries (rmCc). After five rmCc, and compared with wild type (WT) mice, CHT+/- mice exhibited severe and lasting impairments in sustained attention performance, consistent with effects of cholinergic losses on attention. However, rmCc did not affect the integrity of neuronal cell bodies and did not alter the density of cortical synapses. As a cellular mechanism potentially responsible for the attentional impairment in CHT+/- mice, we found that rmCc nearly completely attenuated performance-associated, CHT-mediated choline transport. These results predict that subjects with an already vulnerable cholinergic system will experience severe and lasting cognitive-cholinergic effects after even relatively mild injuries. If confirmed in humans, such subjects may be excluded from, or receive special protection against, activities involving injury risk. Moreover, the treatment and long-term outcome of traumatic brain injuries may benefit from determining the status of cholinergic systems and associated cognitive functions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
| | | | - Vinay Parikh
- Department of Psychology and Neuroscience Program
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22
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Kucinski A, Kim Y, Sarter M. Basal forebrain chemogenetic inhibition disrupts the superior complex movement control of goal-tracking rats. Behav Neurosci 2019; 133:121-134. [PMID: 30688488 DOI: 10.1037/bne0000290] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sign- and goal-tracking behavior signifies the influence of opposed cognitive-motivational styles, with the former being characterized by a tendency for approaching and contacting reward cues, including a readiness for attending, bottom-up, to salient cues, and a relatively greater vulnerability for developing and maintaining addiction-like behaviors. We previously demonstrated that these styles also impact the cognitive-motor interactions that are taxed during traversal of dynamic surfaces, with goal-trackers (GTs) making less movement errors and falling less frequently than sign-trackers (STs). The present experiment tested the hypothesis that complex movement control in GTs, but not STs, depends on activation of the basal forebrain projection system to telencephalic regions. Chemogenetic inhibition of the basal forebrain increased movement errors and falls in GTs during traversal of a rotating zigzag rod but had no significant effect on the relatively lower performance of STs. Neurochemical evidence confirmed the efficacy of the inhibitory designer receptor exclusively activated by designer drug (DREADD). Administration of clozapine-N-oxide (CNO) had no significant effect in GTs not expressing the DREADD. These results indicate that GTs, but not STs, activate the basal forebrain projection system to mediate their relatively superior ability for complex movement control. STs may also serve as an animal model in research on the role of basal forebrain systems in aging- and Parkinson's disease-associated falls. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
| | - Youngsoo Kim
- Department of Psychology and Neuroscience Program
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23
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Sarter M, Lustig C. Cholinergic double duty: cue detection and attentional control. Curr Opin Psychol 2019; 29:102-107. [PMID: 30711909 DOI: 10.1016/j.copsyc.2018.12.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/26/2018] [Accepted: 12/31/2018] [Indexed: 02/08/2023]
Abstract
Cholinergic signaling in the cortex involves fast or transient signaling as well as a relatively slower neuromodulatory component. These two components of cholinergic activity mediate separate yet interacting aspects of cue detection and attentional control. The transient component appears to support the activation of cue-associated task or response sets, whereas the slower modulatory component stabilizes task-set and context representations, therefore potentially facilitating top-down control. Evidence from humans expressing genetic variants of the choline transporter as well as from patients with degenerating cholinergic systems supports the hypothesis that attentional control capacities depend on levels of cholinergic neuromodulation. Deficits in cholinergic-attentional control impact diverse cognitive functions, including timing, working memory, and complex movement control.
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Affiliation(s)
- Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Cindy Lustig
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, United States
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Schelter BO, Shiells H, Baddeley TC, Rubino CM, Ganesan H, Hammel J, Vuksanovic V, Staff RT, Murray AD, Bracoud L, Riedel G, Gauthier S, Jia J, Bentham P, Kook K, Storey JM, Harrington CR, Wischik CM. Concentration-Dependent Activity of Hydromethylthionine on Cognitive Decline and Brain Atrophy in Mild to Moderate Alzheimer's Disease. J Alzheimers Dis 2019; 72:931-946. [PMID: 31658058 PMCID: PMC6918900 DOI: 10.3233/jad-190772] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Although hydromethylthionine is a potent tau aggregation inhibitor, no difference was found in either of two Phase III trials in mild to moderate Alzheimer's disease (AD) comparing doses in the range 150-250 mg/day with 8 mg/day intended as a control. OBJECTIVE To determine how drug exposure is related to treatment response. METHODS A sensitive plasma assay for the drug was used in a population pharmacokinetic analysis of samples from 1,162 of the 1,686 patients who participated in either of the Phase III trials with available samples and efficacy outcome data. RESULTS There are steep concentration-response relationships for steady state plasma levels in the range 0.3-0.8 ng/ml at the 8 mg/day dose. Using a threshold based on the lower limit of quantitation of the assay on Day 1, there are highly significant differences in cognitive decline and brain atrophy in patients with above threshold plasma levels, both for monotherapy and add-on therapy, but with effect sizes reduced by half as add-on. Plasma concentrations in the range 4-21 ng/ml produced by the high doses are not associated with any additional benefit. CONCLUSIONS Hydromethylthionine has pharmacological activity on brain structure and function at the 8 mg/day dose as monotherapy or as add-on to symptomatic treatments. This combined with a plateau at higher doses is consistent with the lack of dose-response seen in the Phase III trials. Treatment benefit is predicted to be maximal at 16 mg/day as monotherapy. A placebo-controlled trial in mild/moderate AD is now ongoing to confirm efficacy at this dose.
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Affiliation(s)
- Bjoern O. Schelter
- TauRx Therapeutics Ltd., Singapore, Singapore
- Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen, UK
| | | | | | | | - Harish Ganesan
- Institute of Clinical Pharmacodynamics, Schenectady, NY, USA
| | - Jeffrey Hammel
- Institute of Clinical Pharmacodynamics, Schenectady, NY, USA
| | - Vesna Vuksanovic
- Aberdeen Biomedical Imaging Center, University of Aberdeen, Foresterhill, Aberdeen, UK
| | | | - Alison D. Murray
- Aberdeen Biomedical Imaging Center, University of Aberdeen, Foresterhill, Aberdeen, UK
| | | | - Gernot Riedel
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Serge Gauthier
- McGill Centre for Studies in Aging, Alzheimer’s Disease Research Unit, and Douglas Mental Health University Institute, Montreal, QC, Canada
| | - Jianping Jia
- Innovation Center for Neurological Disorders, Neurology Department, Xuanwu Hospital, Capital Medical University, Beijing, China
| | | | | | - John M.D. Storey
- TauRx Therapeutics Ltd., Singapore, Singapore
- Department of Chemistry, University of Aberdeen, Aberdeen, UK
| | - Charles R. Harrington
- TauRx Therapeutics Ltd., Singapore, Singapore
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Claude M. Wischik
- TauRx Therapeutics Ltd., Singapore, Singapore
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, UK
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Pitchers KK, Sarter M, Robinson TE. The hot 'n' cold of cue-induced drug relapse. ACTA ACUST UNITED AC 2018; 25:474-480. [PMID: 30115769 PMCID: PMC6097766 DOI: 10.1101/lm.046995.117] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/27/2018] [Indexed: 12/21/2022]
Abstract
Environmental cues associated with rewards can acquire motivational properties. However, there is considerable variation in the extent to which a reward cue gains motivational control over behavior, depending on the individual and the form of the cue. When a discrete cue is paired with food reward, it acquires greater control over motivated behavior in some rats (sign-trackers, STs) than others (goal-trackers, GTs) as indicated by the propensity to approach the cue, the willingness to work to obtain it, and its ability to reinstate reward-seeking behavior. Here, we review studies that employ this ST/GT animal model to investigate characteristics of individuals that are especially susceptible to reward cue-elicited behavior and the involvement of dopamine and acetylcholine neuromodulator systems in the susceptibility to cue-induced drug relapse. First, we discuss individual differences in the attribution of incentive salience to different forms of reward cues and the involvement of the mesolimbic dopamine system. We then discuss individual differences in cognitive/attentional control and the contributions of the cholinergic system in processing reward cues. It is suggested that in STs a propensity to attribute motivational properties to a drug cue is combined with poor attentional control in the face of these cues, making them particularly vulnerable to transition from casual/experimental patterns of drug use to addiction and to cue-induced relapse.
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Affiliation(s)
- Kyle K Pitchers
- Department of Psychology (Biopsychology) and Neuroscience Program, The University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Martin Sarter
- Department of Psychology (Biopsychology) and Neuroscience Program, The University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Terry E Robinson
- Department of Psychology (Biopsychology) and Neuroscience Program, The University of Michigan, Ann Arbor, Michigan 48109, USA
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Sarter M, Phillips KB. The neuroscience of cognitive-motivational styles: Sign- and goal-trackers as animal models. Behav Neurosci 2018; 132:1-12. [PMID: 29355335 DOI: 10.1037/bne0000226] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cognitive-motivational styles describe predominant patterns of processing or biases that broadly influence human cognition and performance. Here we focus on the impact of cognitive-motivational styles on the response to cues predicting the availability of food or addictive drugs. An individual may preferably conduct an analysis of the motivational significance of reward cues, with the result that such cues per se are perceived as rewarding and worth approaching and working for. Alternatively, a propensity for a "cold" analysis of the behavioral utility of a reward cue may yield search behavior for food or drugs but not involve cue approach. Animal models for studying the neuronal mechanisms mediating such styles have originated from research concerning behavioral indices that predict differential vulnerability to addiction-like behaviors. Rats classified as sign- or goal-trackers (STs, GTs) were found to have opposed attentional biases (bottom-up or cue-driven attention vs. top-down or goal-driven attentional control) that are mediated primarily via relatively unresponsive versus elevated levels of cholinergic neuromodulation in the cortex. The capacity for cholinergic neuromodulation in STs is limited by a neuronal choline transporter (CHT) that fails to support increases in cholinergic activity. Moreover, in contrast to STs, the frontal dopamine system in GTs does not respond to the presence of drug cues and, thus, biases against cue-oriented behavior. The opponent cognitive-motivational styles that are indexed by sign- and goal-tracking bestow different cognitive-behavioral vulnerabilities that may contribute to the manifestation of a wide range of neuropsychiatric disorders. (PsycINFO Database Record
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Affiliation(s)
- Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan
| | - Kyra B Phillips
- Department of Psychology and Neuroscience Program, University of Michigan
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The cortical cholinergic system contributes to the top-down control of distraction: Evidence from patients with Parkinson's disease. Neuroimage 2017; 190:107-117. [PMID: 29277400 DOI: 10.1016/j.neuroimage.2017.12.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/27/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022] Open
Abstract
Past animal and human studies robustly report that the cholinergic system plays an essential role in both top-down and bottom-up attentional control, as well as other aspects of cognition (see Ballinger et al., 2016 for a recent review). However, current understanding of how two major cholinergic pathways in the human brain (the basal forebrain-cortical pathway, and the brainstem pedunculopontine-thalamic pathway) contribute to specific cognitive functions remains somewhat limited. To address this issue, we examine how individual variation in the integrity of striatal-dopaminergic, thalamic-cholinergic, and cortical-cholinergic pathways (measured using Positron Emission Tomography in patients with Parkinson's disease) was associated with individual variation in the initial goal-directed focus of attention, the ability to sustain attentional performance over time, and the ability to avoid distraction from a highly-salient, but irrelevant, environmental stimulus. Compared to healthy controls, PD patients performed similarly in the precision of attention-dependent judgments of duration, and in sustaining attention over time. However, PD patients' performance was strikingly more impaired by the distractor. More critically, regression analyses indicated that only cortical-cholinergic integrity, not thalamic-cholinergic or striatal-dopaminergic integrity, made a specific contribution to the ability to resist distraction after controlling for the other variables. These results demonstrate that the basal forebrain cortical cholinergic system serves a specific role in executing top-down control to resist external distraction.
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Pitchers KK, Kane LF, Kim Y, Robinson TE, Sarter M. 'Hot' vs. 'cold' behavioural-cognitive styles: motivational-dopaminergic vs. cognitive-cholinergic processing of a Pavlovian cocaine cue in sign- and goal-tracking rats. Eur J Neurosci 2017; 46:2768-2781. [PMID: 29044780 DOI: 10.1111/ejn.13741] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/08/2017] [Accepted: 10/10/2017] [Indexed: 12/15/2022]
Abstract
Discrete Pavlovian reward cues acquire more potent incentive motivational properties (incentive salience) in some animals (sign-trackers; STs) compared to others (goal-trackers; GTs). Conversely, GTs appear to be better than STs in processing more complex contextual cues, perhaps reflecting their relatively greater bias for goal-directed cue processing. Here, we investigated the activity of two major prefrontal neuromodulatory input systems, dopamine (DA) and acetylcholine (ACh), in response to a discrete Pavlovian cue that was previously paired with cocaine administration in STs and GTs. Rats underwent Pavlovian training in which light cue presentations were either paired or unpaired with an intravenous cocaine infusion. Following a 10-day abstinence period, prefrontal dialysates were collected in STs and GTs during cue presentations in the absence of cocaine. In STs, the cue previously paired with cocaine significantly increased prefrontal DA levels. DA levels remained elevated over baseline across multiple cue presentation blocks, and DA levels and approaches to the cue were significantly correlated. In STs, ACh levels were unaffected by cue presentations. In contrast, in GTs, presentations of the cocaine cue increased prefrontal ACh, but not DA, levels. GTs oriented towards the cue at rates similar to STs, but they did not approach it and elevated ACh levels did not correlate with conditioned orientation. The results indicate a double dissociation between the role of prefrontal DA and ACh in STs and GTs, and suggest that these phenotypes will be useful for studying the role of neuromodulator systems in mediating opponent behavioural-cognitive styles.
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Affiliation(s)
- Kyle K Pitchers
- Department of Psychology and Neuroscience Program, University of Michigan, 530 Church Street, 4030 East Hall, Ann Arbor, MI, 48109, USA
| | - Louisa F Kane
- Department of Psychology and Neuroscience Program, University of Michigan, 530 Church Street, 4030 East Hall, Ann Arbor, MI, 48109, USA
| | - Youngsoo Kim
- Department of Psychology and Neuroscience Program, University of Michigan, 530 Church Street, 4030 East Hall, Ann Arbor, MI, 48109, USA
| | - Terry E Robinson
- Department of Psychology and Neuroscience Program, University of Michigan, 530 Church Street, 4030 East Hall, Ann Arbor, MI, 48109, USA
| | - Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan, 530 Church Street, 4030 East Hall, Ann Arbor, MI, 48109, USA
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Ballinger EC, Ananth M, Talmage DA, Role LW. Basal Forebrain Cholinergic Circuits and Signaling in Cognition and Cognitive Decline. Neuron 2017; 91:1199-1218. [PMID: 27657448 DOI: 10.1016/j.neuron.2016.09.006] [Citation(s) in RCA: 433] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2016] [Indexed: 02/04/2023]
Abstract
Recent work continues to place cholinergic circuits at center stage for normal executive and mnemonic functioning and provides compelling evidence that the loss of cholinergic signaling and cognitive decline are inextricably linked. This Review focuses on the last few years of studies on the mechanisms by which cholinergic signaling contributes to circuit activity related to cognition. We attempt to identify areas of controversy, as well as consensus, on what is and is not yet known about how cholinergic signaling in the CNS contributes to normal cognitive processes. In addition, we delineate the findings from recent work on the extent to which dysfunction of cholinergic circuits contributes to cognitive decline associated with neurodegenerative disorders.
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Affiliation(s)
- Elizabeth C Ballinger
- Medical Scientist Training Program, Program in Neuroscience, Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Mala Ananth
- Program in Neuroscience, Department of Neurobiology & Behavior, Department of Psychiatry & Behavioral Science, Stony Brook University, Stony Brook, NY 11794, USA
| | - David A Talmage
- Department of Pharmacological Sciences, CNS Disorders Center, Center for Molecular Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Lorna W Role
- Department of Neurobiology & Behavior, Neurosciences Institute, CNS Disorders Center, Center for Molecular Medicine, Stony Brook University, Stony Brook, NY 11794, USA.
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Pitchers KK, Phillips KB, Jones JL, Robinson TE, Sarter M. Diverse Roads to Relapse: A Discriminative Cue Signaling Cocaine Availability Is More Effective in Renewing Cocaine Seeking in Goal Trackers Than Sign Trackers and Depends on Basal Forebrain Cholinergic Activity. J Neurosci 2017; 37:7198-7208. [PMID: 28659281 PMCID: PMC5546399 DOI: 10.1523/jneurosci.0990-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/10/2017] [Accepted: 06/16/2017] [Indexed: 12/21/2022] Open
Abstract
Stimuli associated with taking drugs are notorious instigators of relapse. There is, however, considerable variation in the motivational properties of such stimuli, both as a function of the individual and the nature of the stimulus. The behavior of some individuals (sign trackers, STs) is especially influenced by cues paired with reward delivery, perhaps because they are prone to process information via dopamine-dependent, cue-driven, incentive salience systems. Other individuals (goal trackers, GTs) are better able to incorporate higher-order contextual information, perhaps because of better executive/attentional control over behavior, which requires frontal cortical cholinergic activity. We hypothesized, therefore, that a cue that "sets the occasion" for drug taking (a discriminative stimulus, DS) would reinstate cocaine seeking more readily in GTs than STs and that this would require intact cholinergic neurotransmission. To test this, male STs and GTs were trained to self-administer cocaine using an intermittent access schedule with periods of cocaine availability and unavailability signaled by a DS+ and a DS-, respectively. Thereafter, half of the rats received an immunotoxic lesion that destroyed 40-50% of basal forebrain cholinergic neurons and later, after extinction training, were tested for the ability of noncontingent presentations of the DS+ to reinstate cocaine seeking behavior. The DS+ was much more effective in reinstating cocaine seeking in GTs than STs and this effect was abolished by cholinergic losses despite the fact that all rats continued to orient to the DS+ We conclude that vulnerability to relapse involves interactions between individual cognitive-motivational biases and the form of the drug cue encountered.SIGNIFICANCE STATEMENT The most predictable outcome of a diagnosis of addiction is a high chance for relapse. When addicts encounter cues previously associated with drug, their attention may be unduly attracted to such cues and these cues can evoke motivational states that instigate and maintain drug-seeking behavior. Although sign-tracking rats were previously demonstrated to exhibit greater relapse vulnerability to Pavlovian drug cues paired with drug delivery, here, we demonstrate that their counterparts, the goal trackers, are more vulnerable if the drug cue acts to signal drug availability and that the forebrain cholinergic system mediates such vulnerability. Given the importance of contextual cues for triggering relapse and the human cognitive-cholinergic capacity for the processing of such cues, goal trackers model essential aspects of relapse vulnerability.
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Affiliation(s)
- Kyle K Pitchers
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Kyra B Phillips
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Jonte L Jones
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Terry E Robinson
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109
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Hemicholinium-3 sensitive choline transport in human T lymphocytes: Evidence for use as a proxy for brain choline transporter (CHT) capacity. Neurochem Int 2017; 108:410-416. [PMID: 28577989 DOI: 10.1016/j.neuint.2017.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023]
Abstract
The synaptic uptake of choline via the high-affinity, hemicholinium-3-dependent choline transporter (CHT) strongly influences the capacity of cholinergic neurons to sustain acetylcholine (ACh) synthesis and release. To advance research on the impact of CHT capacity in humans, we established the presence of the neuronal CHT protein in human T lymphocytes. Next, we demonstrated CHT-mediated choline transport in human T cells. To address the validity of T cell-based choline uptake as a proxy for brain CHT capacity, we isolated T cells from the spleen, and synaptosomes from cortex and striatum, of wild type and CHT-overexpressing mice (CHT-OXP). Choline uptake capacity in T cells from CHT-OXP mice was two-fold higher than in wild type mice, mirroring the impact of CHT over-expression on synaptosomal CHT-mediated choline uptake. Monitoring T lymphocyte CHT protein and activity may be useful for estimating human CNS cholinergic capacity and for testing hypotheses concerning the contribution of CHT and, more generally, ACh signaling in cognition, neuroinflammation and disease.
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Berry AS, Sarter M, Lustig C. Distinct Frontoparietal Networks Underlying Attentional Effort and Cognitive Control. J Cogn Neurosci 2017; 29:1212-1225. [PMID: 28253080 DOI: 10.1162/jocn_a_01112] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We investigated the brain activity patterns associated with stabilizing performance during challenges to attention. Our findings revealed distinct patterns of frontoparietal activity and functional connectivity associated with increased attentional effort versus preserved performance during challenged attention. Participants performed a visual signal detection task with and without presentation of a perceptual-attention challenge (changing background). The challenge condition increased activation in frontoparietal regions including right mid-dorsal/dorsolateral PFC (RPFC), approximating Brodmann's area 9, and superior parietal cortex. We found that greater behavioral impact of the challenge condition was correlated with greater RPFC activation, suggesting that increased engagement of cognitive control regions is not always sufficient to maintain high levels of performance. Functional connectivity between RPFC and ACC increased during the challenge condition and was also associated with performance declines, suggesting that the level of synchronized engagement of these regions reflects individual differences in attentional effort. Pretask, resting-state RPFC-ACC connectivity did not predict subsequent performance, suggesting that RPFC-ACC connectivity increased dynamically during task performance in response to performance decrement and error feedback. In contrast, functional connectivity between RPFC and superior parietal cortex not only during the task but also during pretask rest was associated with preserved performance in the challenge condition. Together, these data suggest that resting frontoparietal connectivity predicts performance on attention tasks that rely on those same cognitive control networks and that, under challenging conditions, other control regions dynamically couple with this network to initiate the engagement of cognitive control.
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Affiliation(s)
- Anne S Berry
- 1 University of Michigan.,2 Lawrence Berkeley National Laboratory
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Unresponsive Choline Transporter as a Trait Neuromarker and a Causal Mediator of Bottom-Up Attentional Biases. J Neurosci 2017; 37:2947-2959. [PMID: 28193693 DOI: 10.1523/jneurosci.3499-16.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 01/16/2023] Open
Abstract
Some rats [sign-trackers (STs)] are prone to attribute incentive salience to reward cues, which can manifest as a propensity to approach and contact pavlovian cues, and for addiction-like behavior. STs also exhibit poor attentional performance, relative to goal-trackers (GTs), which is associated with attenuated acetylcholine (ACh) levels in prefrontal cortex (Paolone et al., 2013). Here, we demonstrate a cellular mechanism, linked to ACh synthesis, that accounts for attenuated cholinergic capacity in STs. First, we found that electrical stimulation of the basal forebrain increased cortical choline transporter (CHT)-mediated choline transport in GTs, paralleled by a redistribution of CHTs to the synaptic plasma membrane. Neither increases in choline uptake nor translocation of CHTs occurred in STs. Second, and consistent with uptake/translocation alterations, STs demonstrated a reduced ability to support cortical ACh release in vivo compared with GTs after reverse-dialysis to elevate extracellular potassium levels. Third, rats were significantly more likely to develop sign-tracking behavior if treated systemically before pavlovian conditioned approach training with the CHT inhibitor VU6001221. Consistent with its proposed mechanisms, administration of VU6001221 attenuated potassium-evoked ACh levels in prefrontal cortex measured with in vivo microdialysis. We propose that loss of CHT-dependent activation of cortical cholinergic activity in STs degrades top-down executive control over behavior, producing a bias for bottom-up or stimulus-driven attention. Such an attentional bias contributes to nonadaptive reward processing and thus identifies a novel mechanism that can support psychopathology, including addiction.SIGNIFICANCE STATEMENT The vulnerability for addiction-like behavior has been associated with psychological traits, such as the propensity to attribute incentive salience to reward cues that is modeled in rats by sign-tracking behavior. Sign-trackers tend to approach and contact cues associated with reward, whereas their counterparts, the goal-trackers, have a preference for approaching the location of the reward. Here, we show that the capacity of presynaptic cholinergic synapses to respond to stimulation by elevating presynaptic choline uptake and releasing acetylcholine is attenuated in sign-trackers. Furthermore, pharmacological inhibition of choline transport induced sign-tracking behavior. Our findings suggest that reduced levels of cholinergic neuromodulation can mediate an attentional bias toward reward-related cues, thereby allowing such cues to exert relatively greater control over behavior.
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Kim K, Müller MLTM, Bohnen NI, Sarter M, Lustig C. Thalamic cholinergic innervation makes a specific bottom-up contribution to signal detection: Evidence from Parkinson's disease patients with defined cholinergic losses. Neuroimage 2017; 149:295-304. [PMID: 28167350 DOI: 10.1016/j.neuroimage.2017.02.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 01/10/2017] [Accepted: 02/02/2017] [Indexed: 12/13/2022] Open
Abstract
Successful behavior depends on the ability to detect and respond to relevant cues, especially under challenging conditions. This essential component of attention has been hypothesized to be mediated by multiple neuromodulator systems, but the contributions of individual systems (e.g., cholinergic, dopaminergic) have remained unclear. The present study addresses this issue by leveraging individual variation in regionally-specific cholinergic denervation in Parkinson's disease (PD) patients, while controlling for variation in dopaminergic denervation. Patients whose dopaminergic and cholinergic nerve terminal integrity had been previously assessed using Positron Emission Tomography (Bohnen et al., 2012) and controls were tested in a signal detection task that manipulates attentional-perceptual challenge and has been used extensively in both rodents and humans to investigate the cholinergic system's role in responding to such challenges (Demeter et al., 2008; McGaughy and Sarter, 1995; see Hasselmo and Sarter 2011 for review). In simple correlation analyses, measures of midbrain dopaminergic, and both cortical and thalamic cholinergic innervation all predicted preserved signal detection under challenge. However, regression analyses also controlling for age, disease severity, and other variables showed that the only significant independent neurotransmitter-related predictor over and above the other variables in the model was thalamic cholinergic integrity. Furthermore, thalamic cholinergic innervation exclusively predicted hits, not correct rejections, indicating a specific contribution to bottom-up salience processing. These results help define regionally-specific contributions of cholinergic function to different aspects of attention and behavior.
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Affiliation(s)
- Kamin Kim
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Martijn L T M Müller
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States; University of Michigan Morris K. Udall Center of Excellence for Parkinson's Disease Research, Ann Arbor, MI 48109, United States
| | - Nicolaas I Bohnen
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, United States; University of Michigan Morris K. Udall Center of Excellence for Parkinson's Disease Research, Ann Arbor, MI 48109, United States; Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI 48109, United States
| | - Martin Sarter
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, United States; Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, United States; University of Michigan Morris K. Udall Center of Excellence for Parkinson's Disease Research, Ann Arbor, MI 48109, United States
| | - Cindy Lustig
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, United States; Neuroscience Program, University of Michigan, Ann Arbor, MI 48109, United States; University of Michigan Morris K. Udall Center of Excellence for Parkinson's Disease Research, Ann Arbor, MI 48109, United States.
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Pitchers KK, Wood TR, Skrzynski CJ, Robinson TE, Sarter M. The ability for cocaine and cocaine-associated cues to compete for attention. Behav Brain Res 2016; 320:302-315. [PMID: 27890441 DOI: 10.1016/j.bbr.2016.11.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/06/2016] [Accepted: 11/11/2016] [Indexed: 12/18/2022]
Abstract
In humans, reward cues, including drug cues in individuals experiencing addiction, are especially effective in biasing attention towards them, so much so they can disrupt ongoing task performance. It is not known, however, whether this happens in rats. To address this question, we developed a behavioral paradigm to assess the capacity of an auditory drug (cocaine) cue to evoke cocaine-seeking behavior, thus distracting thirsty rats from performing a well-learned sustained attention task (SAT) to obtain a water reward. First, it was determined that an auditory cocaine cue (tone-CS) reinstated drug-seeking equally in sign-trackers (STs) and goal-trackers (GTs), which otherwise vary in the propensity to attribute incentive salience to a localizable drug cue. Next, we tested the ability of an auditory cocaine cue to disrupt performance on the SAT in STs and GTs. Rats were trained to self-administer cocaine intravenously using an Intermittent Access self-administration procedure known to produce a progressive increase in motivation for cocaine, escalation of intake, and strong discriminative stimulus control over drug-seeking behavior. When presented alone, the auditory discriminative stimulus elicited cocaine-seeking behavior while rats were performing the SAT, but it was not sufficiently disruptive to impair SAT performance. In contrast, if cocaine was available in the presence of the cue, or when administered non-contingently, SAT performance was severely disrupted. We suggest that performance on a relatively automatic, stimulus-driven task, such as the basic version of the SAT used here, may be difficult to disrupt with a drug cue alone. A task that requires more top-down cognitive control may be needed.
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Affiliation(s)
- Kyle K Pitchers
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
| | - Taylor R Wood
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Cari J Skrzynski
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Terry E Robinson
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Martin Sarter
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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