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Response inhibition and response monitoring in a saccadic double-step task in schizophrenia. Brain Cogn 2015; 95:90-8. [PMID: 25769133 DOI: 10.1016/j.bandc.2015.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/03/2014] [Accepted: 01/15/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cognitive control impairments are linked to functional outcome in schizophrenia. The goal of the current study was to investigate precise abnormalities in two aspects of cognitive control: reactively changing a prepared response, and monitoring performance and adjusting behavior accordingly. We adapted an oculomotor task from neurophysiological studies of the cellular basis of cognitive control in nonhuman primates. METHODS 16 medicated outpatients with schizophrenia (SZ) and 18 demographically-matched healthy controls performed the modified double-step task. In this task, participants were required to make a saccade to a visual target. Infrequently, the target jumped to a new location and participants were instructed to rapidly inhibit and change their response. A race model provided an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by measuring reaction time (RT) adjustments based on trial history. RESULTS SZ patients had normal visually-guided saccadic RTs but required more time to switch the response to the new target location. Additionally, the estimated latency of inhibition was longer in patients and related to employment. Finally, although both groups slowed down on trials that required inhibiting and changing a response, patients showed exaggerated performance-based adjustments in RTs, which was correlated with positive symptom severity. CONCLUSIONS SZ patients have impairments in rapidly inhibiting eye movements and show idiosyncratic response monitoring. These results are consistent with functional abnormalities in a network involving cortical oculomotor regions, the superior colliculus, and basal ganglia, as described in neurophysiological studies of non-human primates using an identical paradigm, and provide a translational bridge for understanding cognitive symptoms of SZ.
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Bari A, Dec A, Lee AW, Lee J, Song D, Dale E, Peterson J, Zorn S, Huang X, Campbell B, Robbins TW, West AR. Enhanced inhibitory control by neuropeptide Y Y5 receptor blockade in rats. Psychopharmacology (Berl) 2015; 232:959-73. [PMID: 25194952 DOI: 10.1007/s00213-014-3730-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 08/24/2014] [Indexed: 12/25/2022]
Abstract
RATIONALE The neuropeptide Y (NPY) system acts in synergy with the classic neurotransmitters to regulate a large variety of functions including autonomic, affective, and cognitive processes. Research on the effects of NPY in the central nervous system has focused on food intake control and affective processes, but growing evidence of NPY involvement in attention-deficit/hyperactivity disorder (ADHD) and other psychiatric conditions motivated the present study. OBJECTIVES We tested the effects of the novel and highly selective NPY Y5 receptor antagonist Lu AE00654 on impulsivity and the underlying cortico-striatal circuitry in rats to further explore the possible involvement of the NPY system in pathologies characterized by inattention and impulsive behavior. RESULTS A low dose of Lu AE00654 (0.03 mg/kg) selectively facilitated response inhibition as measured by the stop-signal task, whereas no effects were found at higher doses (0.3 and 3 mg/kg). Systemic administration of Lu AE00654 also enhanced the inhibitory influence of the dorsal frontal cortex on neurons in the caudate-putamen, this fronto-striatal circuitry being implicated in the executive control of behavior. Finally, by locally injecting a Y5 agonist, we observed reciprocal activation between dorsal frontal cortex and caudate-putamen neurons. Importantly, the effects of the Y5 agonist were attenuated by pretreatment with Lu AE00654, confirming the presence of Y5 binding sites modulating functional interactions within frontal-subcortical circuits. CONCLUSIONS These results suggest that the NPY system modulates inhibitory neurotransmission in brain areas important for impulse control, and may be relevant for the treatment of pathologies such as ADHD and drug abuse.
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Affiliation(s)
- A Bari
- Behavioral and Clinical Neuroscience Institute and Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK,
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Cognitive control of gaze in bipolar disorder and schizophrenia. Psychiatry Res 2015; 225:254-62. [PMID: 25601802 PMCID: PMC4361560 DOI: 10.1016/j.psychres.2014.12.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 11/12/2014] [Accepted: 12/22/2014] [Indexed: 01/30/2023]
Abstract
The objective of the present study was to compare two components of executive functioning, response monitoring and inhibition, in bipolar disorder (BP) and schizophrenia (SZ). The saccadic countermanding task is a translational paradigm optimized for detecting subtle abnormalities in response monitoring and response inhibition. We have previously reported countermanding performance abnormalities in SZ, but the degree to which these impairments are shared by other psychotic disorders is unknown. 18 BP, 17 SZ, and 16 demographically matched healthy controls (HC) participated in a saccadic countermanding task. Performance on the countermanding task is approximated as a race between movement generation and inhibition processes; this model provides an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by the reaction time (RT) adjustments based on trial history. Like SZ patients, BP patients needed more time to cancel a planned movement. The two patient groups had equivalent inhibition efficiency. On trial history-based RT adjustments, however, we found a trend towards exaggerated trial history-based slowing in SZ compared to BP. Findings have implications for understanding the neurobiology of cognitive control, for defining the etiological overlap between schizophrenia and bipolar disorder, and for developing pharmacological treatments of cognitive impairments.
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Young JW, Geyer MA. Developing treatments for cognitive deficits in schizophrenia: the challenge of translation. J Psychopharmacol 2015; 29:178-96. [PMID: 25516372 PMCID: PMC4670265 DOI: 10.1177/0269881114555252] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Schizophrenia is a life-long debilitating mental disorder affecting tens of millions of people worldwide. The serendipitous discovery of antipsychotics focused pharmaceutical research on developing a better antipsychotic. Our understanding of the disorder has advanced however, with the knowledge that cognitive enhancers are required for patients in order to improve their everyday lives. While antipsychotics treat psychosis, they do not enhance cognition and hence are not antischizophrenics. Developing pro-cognitive therapeutics has been extremely difficult, however, especially when no approved treatment exists. In lieu of stumbling on an efficacious treatment, developing targeted compounds can be facilitated by understanding the neural mechanisms underlying altered cognitive functioning in patients. Equally importantly, these cognitive domains will need to be measured similarly in animals and humans so that novel targets can be tested prior to conducting expensive clinical trials. To date, the limited similarity of testing across species has resulted in a translational bottleneck. In this review, we emphasize that schizophrenia is a disorder characterized by abnormal cognitive behavior. Quantifying these abnormalities using tasks having cross-species validity would enable the quantification of comparable processes in rodents. This approach would increase the likelihood that the neural substrates underlying relevant behaviors will be conserved across species. Hence, we detail cross-species tasks which can be used to test the effects of manipulations relevant to schizophrenia and putative therapeutics. Such tasks offer the hope of providing a bridge between non-clinical and clinical testing that will eventually lead to treatments developed specifically for patients with deficient cognition.
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Affiliation(s)
- JW Young
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - MA Geyer
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
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Voon V, Dalley JW. Translatable and Back-Translatable Measurement of Impulsivity and Compulsivity: Convergent and Divergent Processes. Curr Top Behav Neurosci 2015; 28:53-91. [PMID: 27418067 DOI: 10.1007/7854_2015_5013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Impulsivity and compulsivity have emerged as important dimensional constructs that challenge traditional psychiatric classification systems. Both are present in normal healthy populations where the need to act quickly and repeatedly without hesitation can be highly advantageous. However, when excessively expressed, impulsive and compulsive behavior can lead to adverse consequences and spectrum disorders exemplified by attention-deficit/hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), autism, and drug addiction. Impulsive individuals have difficulty in deferring gratification and are inclined to 'jump the gun' and respond prematurely before sufficient information is gathered. Compulsivity involves repetitive behavior often motivated by the need to reduce or prevent anxiety, thus leading to the maladaptive perseveration of behavior. Defined in this way, impulsivity and compulsivity could be viewed as separate entities or 'traits' but overwhelming evidence indicates that both may be present in the same disorder, either concurrently or even separately at different time points. Herein we discuss the neural and cognitive heterogeneity of impulsive and compulsive endophenotypes. These constructs map onto distinct fronto-striatal neural and neurochemical structures interacting both at nodal convergent points and as opponent processes highlighting both the heterogeneity and the commonalities of function. We focus on discoveries made using both translational research methodologies and studies exclusively in humans, and implications for treatment intervention in disorders in which impulsive and compulsive symptoms prevail. We emphasize the relevance of these constructs for understanding dimensional psychiatry.
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Affiliation(s)
- Valerie Voon
- Behavioral and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK.
- Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK.
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK.
| | - Jeffrey W Dalley
- Behavioral and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
- Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK
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Loomis S, McCarthy A, Baxter C, Kellett DO, Edgar DM, Tricklebank M, Gilmour G. Distinct pro-vigilant profile induced in rats by the mGluR5 potentiator LSN2814617. Psychopharmacology (Berl) 2015; 232:3977-89. [PMID: 25902875 PMCID: PMC4600478 DOI: 10.1007/s00213-015-3936-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/02/2015] [Indexed: 12/30/2022]
Abstract
While treatment options are available, excessive daytime sleepiness (EDS) remains a significant unmet medical need for many patients. Relatively little rodent behavioural pharmacology has been conducted in this context to assess potential pro-vigilant compounds for their ability to restore functional capacity following experimentally induced sleep loss. Male Wistar rats were prepared for electroencephalographic (EEG) recording and subject to 11 h of sleep restriction using a biofeedback-induced cage rotation protocol. A simple response latency task (SRLT) was used to behaviourally index sleep restriction and the effects of pro-vigilant compounds: modafinil, D-amphetamine, caffeine, and the mGlu5-positive allosteric modulator LSN2814617. Sleep restriction resulted in a consistent, quantified loss of non-rapid eye movement (NREM) and REM sleep that impaired SRLT performance in a manner suggestive of progressive task disengagement. In terms of EEG parameters, all compounds induced wakefulness. Amphetamine treatment further decreased SRLT performance capacity, whereas the other three compounds decreased omissions and allowed animals to re-engage in the task. Caffeine and modafinil also significantly increased premature responses during this period, an effect not observed for LSN2814617. While all compounds caused compensatory sleep responses, the magnitude of compensation observed for LSN2814617 was much smaller than would be predicted to result from the prolongation of wakefulness exhibited. Using simple response latencies to index performance, an mGlu5 PAM dramatically increased wakefulness and improved functional capacity of sleep-restricted animals, without eliciting a proportionate compensatory sleep response. This effect was qualitatively distinct from that of amphetamine, caffeine and modafinil.
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Affiliation(s)
- Sally Loomis
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Andrew McCarthy
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Christopher Baxter
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Daniel O. Kellett
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Dale M. Edgar
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Mark Tricklebank
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH England UK
| | - Gary Gilmour
- Lilly Research Laboratories, Eli Lilly & Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH, England, UK.
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D'Amour-Horvat V, Leyton M. Impulsive actions and choices in laboratory animals and humans: effects of high vs. low dopamine states produced by systemic treatments given to neurologically intact subjects. Front Behav Neurosci 2014; 8:432. [PMID: 25566001 PMCID: PMC4274964 DOI: 10.3389/fnbeh.2014.00432] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/26/2014] [Indexed: 11/13/2022] Open
Abstract
Increases and decreases in dopamine (DA) transmission have both been suggested to influence reward-related impulse-control. The present literature review suggests that, in laboratory animals, the systemic administration of DA augmenters preferentially increases susceptibility to premature responding; with continued DA transmission, reward approach behaviors are sustained. Decreases in DA transmission, in comparison, diminish the appeal of distal and difficult to obtain rewards, thereby increasing susceptibility to temporal discounting and other forms of impulsive choice. The evidence available in humans is not incompatible with this model but is less extensive.
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Affiliation(s)
| | - Marco Leyton
- Department of Psychology, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada ; Center for Studies in Behavioral Neurobiology, Concordia University Montreal, QC, Canada
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The dopamine reuptake inhibitor MRZ-9547 increases progressive ratio responding in rats. Int J Neuropsychopharmacol 2014; 17:2045-56. [PMID: 24964269 DOI: 10.1017/s1461145714000996] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Drugs that are able to shift effort-related decision making in intact rats towards high-effort response options are largely unknown. Here, we examined the effects of two candidate drugs, MRZ-9547 and its l-enantiomer MRZ-9546 on progressive ratio (PR) responding using two different tasks, a standard PR task that involves increasing ratio requirements and a PR/chow feeding choice task in which animals can lever press for preferred food pellets under a PR schedule or approach freely available less preferred lab chow. Furthermore, we assessed the mechanisms of action of both drugs using in vitro-assay methods and in vivo-microdialysis. Results reveal that MRZ-9547 is a selective dopamine transporter (DAT) inhibitor that moderately stimulated striatal dopamine release. MRZ-9546 was a much less potent DAT inhibitor. Furthermore, MRZ-9547 dose dependently increased the tendency to work for food reinforcement both in the standard PR task and the PR/chow feeding choice task, MRZ-9546 was considerably less active. Relative to MRZ-9547, other DAT-interfering drugs had only moderate (methylphenidate) or marginal (modafinil, d-amphetamine) stimulant effects on PR responding in either task. Collectively, our data demonstrate that the DAT inhibitor MRZ-9547 can markedly stimulate PR responding and shift effort-related decision making in intact rats towards high-effort response options. An analysis of effort-related decision making in rodents could provide an animal model for motivational dysfunctions related to effort expenditure such as fatigue, e.g. in Parkinson's disease or major depression. Our findings suggest that DAT inhibitors such as MRZ-9547 could be potentially useful for treating energy-related symptoms in neurological or neuropsychiatric disorders.
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Claassen DO, van den Wildenberg WPM, Harrison MB, van Wouwe NC, Kanoff K, Neimat JS, Wylie SA. Proficient motor impulse control in Parkinson disease patients with impulsive and compulsive behaviors. Pharmacol Biochem Behav 2014; 129:19-25. [PMID: 25459105 DOI: 10.1016/j.pbb.2014.11.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 11/16/2014] [Accepted: 11/22/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Parkinson disease (PD) patients treated with dopamine agonist therapy can develop maladaptive reward-driven behaviors, known as impulse control disorder (ICD). In this study, we assessed if ICD patients have evidence of motor-impulsivity. METHODS We used the stop-signal task in a cohort of patients with and without active symptoms of ICD to evaluate motor-impulsivity. Of those with PD, 12 were diagnosed with ICD symptoms (PD-ICD) and were assessed before clinical reduction of dopamine agonist medication; 12 were without symptoms of ICD [PD-control] and taking equivalent dosages of dopamine agonist. Levodopa, if present, was maintained in both settings. Groups were similar in age, duration, and severity of motor symptoms, levodopa co-therapy, and total levodopa daily dose. All were tested in the dopamine agonist medicated and acutely withdrawn (24 h) state, in a counterbalanced manner. Primary outcome measures were mean reaction time to correct go trials (go reaction time), and mean stop-signal reaction time (SSRT). RESULTS ICD patients produce faster SSRT than both Healthy Controls, and PD-Controls. Faster SSRT in ICD patients is apparent in both dopamine agonist medication states. Also, we show unique dopamine medication effects on Go Reaction time (GoRT). In dopamine agonist monotherapy patients, dopamine agonist administration speeds GoRT. Conversely, in those with levodopa co-therapy, dopamine agonist administration slows. DISCUSSION PD patients with active ICD symptoms are significantly faster at stopping initiated motor actions, and this is not altered by acute dopamine agonist withdrawal. In addition, the effect of dopamine agonist on GoRT is strongly influenced by the presence or absence of levodopa, even though levodopa co-therapy does not appear to influence SSRT. We discuss these findings as they pertain to the multifaceted definition of 'impulsivity,' the lack of evidence for motor-impulsivity in PD-ICD, and dopamine effects on motor-control in PD.
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Affiliation(s)
- Daniel O Claassen
- Department of Neurology, Vanderbilt University, Nashville, TN, United States.
| | | | - Madaline B Harrison
- Department of Neurology, University of Virginia, Charlottesville, VA, United States
| | - Nelleke C van Wouwe
- Department of Neurology, Vanderbilt University, Nashville, TN, United States
| | - Kristen Kanoff
- Department of Neurology, Vanderbilt University, Nashville, TN, United States
| | - Joseph S Neimat
- Department of Neurosurgery, Vanderbilt University, Nashville, TN, United States
| | - Scott A Wylie
- Department of Neurology, Vanderbilt University, Nashville, TN, United States
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60
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Jupp B, Dalley JW. Convergent pharmacological mechanisms in impulsivity and addiction: insights from rodent models. Br J Pharmacol 2014; 171:4729-66. [PMID: 24866553 PMCID: PMC4209940 DOI: 10.1111/bph.12787] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/02/2014] [Accepted: 05/12/2014] [Indexed: 01/15/2023] Open
Abstract
Research over the last two decades has widely demonstrated that impulsivity, in its various forms, is antecedent to the development of drug addiction and an important behavioural trait underlying the inability of addicts to refrain from continued drug use. Impulsivity describes a variety of rapidly and prematurely expressed behaviours that span several domains from impaired response inhibition to an intolerance of delayed rewards, and is a core symptom of attention deficit hyperactivity disorder (ADHD) and other brain disorders. Various theories have been advanced to explain how impulsivity interacts with addiction both causally and as a consequence of chronic drug abuse; these acknowledge the strong overlaps in neural circuitry and mechanisms between impulsivity and addiction and the seemingly paradoxical treatment of ADHD with stimulant drugs with high abuse potential. Recent years have witnessed unprecedented progress in the elucidation of pharmacological mechanisms underpinning impulsivity. Collectively, this work has significantly improved the prospect for new therapies in ADHD as well as our understanding of the neural mechanisms underlying the shift from recreational drug use to addiction. In this review, we consider the extent to which pharmacological interventions that target impulsive behaviour are also effective in animal models of addiction. We highlight several promising examples of convergence based on empirical findings in rodent-based studies.
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Affiliation(s)
- B Jupp
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of CambridgeCambridge, UK
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, Australia
| | - J W Dalley
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of CambridgeCambridge, UK
- Department of Psychiatry, University of CambridgeCambridge, UK
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Davies W, Humby T, Trent S, Eddy JB, Ojarikre OA, Wilkinson LS. Genetic and pharmacological modulation of the steroid sulfatase axis improves response control; comparison with drugs used in ADHD. Neuropsychopharmacology 2014; 39:2622-32. [PMID: 24842408 PMCID: PMC4140762 DOI: 10.1038/npp.2014.115] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 04/10/2014] [Accepted: 05/02/2014] [Indexed: 02/08/2023]
Abstract
Maladaptive response control is a feature of many neuropsychiatric conditions, including attention deficit hyperactivity disorder (ADHD). As ADHD is more commonly diagnosed in males than females, a pathogenic role for sex-linked genes has been suggested. Deletion or point mutation of the X-linked STS gene, encoding the enzyme steroid sulfatase (STS) influences risk for ADHD. We examined whether deletion of the Sts gene in the 39,X(Y*)O mouse model, or pharmacological manipulation of the STS axis, via administration of the enzyme substrate dehydroepiandrosterone sulfate or the enzyme inhibitor COUMATE, influenced behavior in a novel murine analog of the stop-signal reaction time task used to detect inhibitory deficits in individuals with ADHD. Unexpectedly, both the genetic and pharmacological treatments resulted in enhanced response control, manifest as highly specific effects in the ability to cancel a prepotent action. For all three manipulations, the effect size was comparable to that seen with the commonly used ADHD therapeutics methylphenidate and atomoxetine. Hence, converging genetic and pharmacological evidence indicates that the STS axis is involved in inhibitory processes and can be manipulated to give rise to improvements in response control. While the precise neurobiological mechanism(s) underlying the effects remain to be established, there is the potential for exploiting this pathway in the treatment of disorders where failures in behavioral inhibition are prominent.
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Affiliation(s)
- William Davies
- Behavioral Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK,MRC Centre for Neuropsychiatric Genetics and Genomics and Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK,Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - Trevor Humby
- Behavioral Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK,MRC Centre for Neuropsychiatric Genetics and Genomics and Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK,Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - Simon Trent
- Behavioral Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK,MRC Centre for Neuropsychiatric Genetics and Genomics and Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK,Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - Jessica B Eddy
- Behavioral Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK,MRC Centre for Neuropsychiatric Genetics and Genomics and Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK
| | - Obah A Ojarikre
- MRC National Institute for Medical Research, London, Cardiff, UK
| | - Lawrence S Wilkinson
- Behavioral Genetics Group, Schools of Psychology and Medicine, Cardiff University, Cardiff, UK,MRC Centre for Neuropsychiatric Genetics and Genomics and Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK,Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK,School of Psychology, Cardiff University, Tower Building, Cardiff CF10 3AT, UK, Tel: +44 (0)29 2087 0357, Fax: +44 (0)29 2087 4858, E-mail:
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van Velzen LS, Vriend C, de Wit SJ, van den Heuvel OA. Response inhibition and interference control in obsessive-compulsive spectrum disorders. Front Hum Neurosci 2014; 8:419. [PMID: 24966828 PMCID: PMC4052433 DOI: 10.3389/fnhum.2014.00419] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/24/2014] [Indexed: 12/30/2022] Open
Abstract
Over the past 20 years, motor response inhibition and interference control have received considerable scientific effort and attention, due to their important role in behavior and the development of neuropsychiatric disorders. Results of neuroimaging studies indicate that motor response inhibition and interference control are dependent on cortical–striatal–thalamic–cortical (CSTC) circuits. Structural and functional abnormalities within the CSTC circuits have been reported for many neuropsychiatric disorders, including obsessive–compulsive disorder (OCD) and related disorders, such as attention-deficit hyperactivity disorder, Tourette’s syndrome, and trichotillomania. These disorders also share impairments in motor response inhibition and interference control, which may underlie some of their behavioral and cognitive symptoms. Results of task-related neuroimaging studies on inhibitory functions in these disorders show that impaired task performance is related to altered recruitment of the CSTC circuits. Previous research has shown that inhibitory performance is dependent upon dopamine, noradrenaline, and serotonin signaling, neurotransmitters that have been implicated in the pathophysiology of these disorders. In this narrative review, we discuss the common and disorder-specific pathophysiological mechanisms of inhibition-related dysfunction in OCD and related disorders.
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Affiliation(s)
- Laura S van Velzen
- GGZ InGeest , Amsterdam , Netherlands ; Neuroscience Campus Amsterdam (NCA) , Amsterdam , Netherlands
| | - Chris Vriend
- GGZ InGeest , Amsterdam , Netherlands ; Neuroscience Campus Amsterdam (NCA) , Amsterdam , Netherlands ; Department of Psychiatry, VU University Medical Center , Amsterdam , Netherlands ; Department of Anatomy and Neurosciences, VU University Medical Center , Amsterdam , Netherlands
| | - Stella J de Wit
- GGZ InGeest , Amsterdam , Netherlands ; Neuroscience Campus Amsterdam (NCA) , Amsterdam , Netherlands ; Department of Psychiatry, VU University Medical Center , Amsterdam , Netherlands
| | - Odile A van den Heuvel
- Neuroscience Campus Amsterdam (NCA) , Amsterdam , Netherlands ; Department of Psychiatry, VU University Medical Center , Amsterdam , Netherlands ; Department of Anatomy and Neurosciences, VU University Medical Center , Amsterdam , Netherlands
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63
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Urban KR, Gao WJ. Performance enhancement at the cost of potential brain plasticity: neural ramifications of nootropic drugs in the healthy developing brain. Front Syst Neurosci 2014; 8:38. [PMID: 24860437 PMCID: PMC4026746 DOI: 10.3389/fnsys.2014.00038] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 03/03/2014] [Indexed: 11/13/2022] Open
Abstract
Cognitive enhancement is perhaps one of the most intriguing and controversial topics in neuroscience today. Currently, the main classes of drugs used as potential cognitive enhancers include psychostimulants (methylphenidate (MPH), amphetamine), but wakefulness-promoting agents (modafinil) and glutamate activators (ampakine) are also frequently used. Pharmacologically, substances that enhance the components of the memory/learning circuits—dopamine, glutamate (neuronal excitation), and/or norepinephrine—stand to improve brain function in healthy individuals beyond their baseline functioning. In particular, non-medical use of prescription stimulants such as MPH and illicit use of psychostimulants for cognitive enhancement have seen a recent rise among teens and young adults in schools and college campuses. However, this enhancement likely comes with a neuronal, as well as ethical, cost. Altering glutamate function via the use of psychostimulants may impair behavioral flexibility, leading to the development and/or potentiation of addictive behaviors. Furthermore, dopamine and norepinephrine do not display linear effects; instead, their modulation of cognitive and neuronal function maps on an inverted-U curve. Healthy individuals run the risk of pushing themselves beyond optimal levels into hyperdopaminergic and hypernoradrenergic states, thus vitiating the very behaviors they are striving to improve. Finally, recent studies have begun to highlight potential damaging effects of stimulant exposure in healthy juveniles. This review explains how the main classes of cognitive enhancing drugs affect the learning and memory circuits, and highlights the potential risks and concerns in healthy individuals, particularly juveniles and adolescents. We emphasize the performance enhancement at the potential cost of brain plasticity that is associated with the neural ramifications of nootropic drugs in the healthy developing brain.
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Affiliation(s)
- Kimberly R Urban
- Department of Psychology, University of Delaware Newark, DE, USA
| | - Wen-Jun Gao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
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Farr OM, Hu S, Matuskey D, Zhang S, Abdelghany O, Li CSR. The effects of methylphenidate on cerebral activations to salient stimuli in healthy adults. Exp Clin Psychopharmacol 2014; 22:154-65. [PMID: 24188171 PMCID: PMC4105943 DOI: 10.1037/a0034465] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Detection of a salient stimulus is critical to cognitive functioning. A stimulus is salient when it appears infrequently, carries high motivational value, and/or when it dictates changes in behavior. Individuals with neurological conditions that implicate altered catecholaminergic signaling, such as those with attention deficit hyperactivity disorder, are impaired in detecting salient stimuli, a deficit that can be remediated by catecholaminergic medications. However, the effects of these catecholaminergic agents on cerebral activities during saliency processing within the context of the stop-signal task are not clear. Here, we examined the effects of a single oral dose (45 mg) of methylphenidate in 24 healthy adults performing the stop-signal task during functional MRI (fMRI). Compared to 92 demographically matched adults who did not receive any medications, the methylphenidate group showed higher activations in bilateral caudate head, primary motor cortex, and the right inferior parietal cortex during stop as compared to go trials (p < .05, corrected for family-wise error of multiple comparisons). These results show that methylphenidate enhances saliency processing by promoting specific cerebral regional activities. These findings may suggest a neural basis for catecholaminergic treatment of attention disorders.
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Affiliation(s)
- Olivia M. Farr
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520
| | - Sien Hu
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519
| | - David Matuskey
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519
| | - Sheng Zhang
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519
| | - Osama Abdelghany
- Investigational Drug Service, Yale New Haven Hospital, New Haven, CT 06519
| | - Chiang-shan R. Li
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520,Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519,Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520
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65
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Carmack SA, Block CL, Howell KK, Anagnostaras SG. Methylphenidate enhances acquisition and retention of spatial memory. Neurosci Lett 2014; 567:45-50. [PMID: 24680747 DOI: 10.1016/j.neulet.2014.03.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/07/2014] [Accepted: 03/18/2014] [Indexed: 11/20/2022]
Abstract
Psychostimulants containing methylphenidate (MPH) are increasingly being used both on and off-label to enhance learning and memory. Still, almost no studies have investigated MPH's ability to specifically improve spatial or long-term memory. Here we examined the effect of training with 1 or 10mg/kg MPH on hidden platform learning in the Morris water maze. 10mg/kg MPH improved memory acquisition and retention, while 1mg/kg MPH improved memory retention. Taken together with prior evidence that low, clinically relevant, doses of MPH (0.01-1mg/kg MPH) enhance fear memory we conclude that MPH broadly enhances memory.
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Affiliation(s)
- Stephanie A Carmack
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego 92093-0109, United States
| | - Carina L Block
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego 92093-0109, United States
| | - Kristin K Howell
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego 92093-0109, United States
| | - Stephan G Anagnostaras
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego 92093-0109, United States; Program in Neurosciences, University of California, San Diego 92093-0109, United States.
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66
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Nandam LS, Hester R, Bellgrove MA. Dissociable and common effects of methylphenidate, atomoxetine and citalopram on response inhibition neural networks. Neuropsychologia 2014; 56:263-70. [PMID: 24513025 DOI: 10.1016/j.neuropsychologia.2014.01.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 01/27/2014] [Accepted: 01/31/2014] [Indexed: 11/27/2022]
Abstract
Response inhibition is an executive function that allows the detection and modification of unwanted actions. Its underlying neurochemistry and neurobiology have been explored by combining classic neuropsychological paradigms, such as the go/no-go task (GNG), with targeted pharmacology and functional neuroimaging. We sought to further this literature by using single doses of methylphenidate (30 mg), atomoxetine (60 mg), citalopram (30 mg) and placebo to probe dopaminergic, noradrenergic and serotonergic aspects of response inhibition. Twenty-seven (27) healthy, right-handed males participated in a randomised, double blind, placebo-controlled, within subject, crossover fMRI study to examine stop-related BOLD activation correlates of a modified GNG task. Methylphenidate demonstrated activation versus placebo in the pregenual cingulate (dorsal anterior cingulate), right inferior frontal, left middle frontal, left angular and right superior temporal gyri and right caudate. Atomoxetine demonstrated activation versus placebo across a broad network of cortical regions. Both methylphenidate and atomoxetine, but not citalopram, activated superior temporal, right inferior frontal and left middle frontal clusters. Citalopram only activated the left inferior occipital lobe. Taking the above as functionally defined regions of interest, we examined the specificity of stop-related drug activity by comparing mean activations across the four conditions. Only methylphenidate demonstrated drug-specific effects with increased activation of the pregenual cingulate and decreased activation of the caudate. Direct comparison of methylphenidate and atomoxetine showed broad recruitment of prefrontal regions but specific effects of methylphenidate in the pregenual cingulate and caudate revealing dissociable modulations of response inhibition networks.
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Affiliation(s)
- L Sanjay Nandam
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert Hester
- School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Mark A Bellgrove
- Monash University, School of Psychology and Psychiatry, Melbourne 3800, Victoria, Australia.
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67
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Kolokotroni KZ, Rodgers RJ, Harrison AA. Trait differences in response to chronic nicotine and nicotine withdrawal in rats. Psychopharmacology (Berl) 2014; 231:567-80. [PMID: 24037510 DOI: 10.1007/s00213-013-3270-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/27/2013] [Indexed: 02/01/2023]
Abstract
INTRODUCTION Understanding an individual's vulnerability to drug addiction has important implications for the development of effective personal treatment plans. Although theories acknowledge impulsive behaviour as a key component of drug addiction, little is known about the influence of trait impulsivity on an individual's susceptibility to the effects of psychostimulants on impulsivity at critical phases of the addiction cycle. METHODS This study investigated the short and longer-term effects of chronic nicotine administration on impulsive choice in rats selected for high (HI) and low impulsivity (LI) on a delay discounting task. Rats prepared with subcutaneously osmotic mini-pumps received either nicotine (3.16 mg/kg/day [freebase]) or saline for 7 days. Performance was assessed during chronic treatment, early and late withdrawal, and in response to acute nicotine challenges following prolonged abstinence. RESULTS Chronic nicotine increased impulsive choice in LI but not HI animals. Spontaneous withdrawal was associated with a nicotine abstinence syndrome, the early stages of which were characterised by opposing effects on impulsive choice in HI and LI animals. A transient decrease in impulsivity was observed in HI animals whilst the LI group remained more impulsive for up to 1 week following drug termination. Following normalisation of behaviour, acute nicotine challenges (0.125, 0.25, 0.5 mg/kg, SC) markedly increased impulsive choice regardless of trait impulsivity and drug history. CONCLUSION The results indicate that only LI individuals are vulnerable to chronic drug- and withdrawal-induced impairments in self-control which may increase the likelihood of the transition to, and maintenance of, nicotine dependence.
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Affiliation(s)
- K Z Kolokotroni
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds, LS2 9JT, UK,
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68
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Carmack SA, Howell KK, Rasaei K, Reas ET, Anagnostaras SG. Animal model of methylphenidate's long-term memory-enhancing effects. Learn Mem 2014; 21:82-9. [PMID: 24434869 PMCID: PMC3895222 DOI: 10.1101/lm.033613.113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Methylphenidate (MPH), introduced more than 60 years ago, accounts for two-thirds of current prescriptions for attention deficit hyperactivity disorder (ADHD). Although many studies have modeled MPH's effect on executive function, almost none have directly modeled its effect on long-term memory (LTM), even though improvement in LTM is a critical target of therapeutic intervention in ADHD. We examined the effects of a wide range of doses of MPH (0.01–10 mg/kg, i.p.) on Pavlovian fear learning, a leading model of memory. MPH's effects were then compared to those of atomoxetine (0.1–10 mg/kg, i.p.), bupropion (0.5–20 mg/kg, i.p.), and citalopram (0.01–10 mg/kg, i.p.). At low, clinically relevant doses, MPH enhanced fear memory; at high doses it impaired memory. MPH's memory-enhancing effects were not confounded by its effects on locomotion or anxiety. Further, MPH-induced memory enhancement seemed to require both dopamine and norepinephrine transporter inhibition. Finally, the addictive potential of MPH (1 mg/kg and 10 mg/kg) was compared to those of two other psychostimulants, amphetamine (0.005 mg/kg and 1.5 mg/kg) and cocaine (0.15 mg/kg and 15 mg/kg), using a conditioned place preference and behavioral sensitization paradigm. We found that memory-enhancing effects of psychostimulants observed at low doses are readily dissociable from their reinforcing and locomotor activating effects at high doses. Together, our data suggest that fear conditioning will be an especially fruitful platform for modeling the effects of psychostimulants on LTM in drug development.
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Affiliation(s)
- Stephanie A Carmack
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego, California 92093-0109, USA
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69
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Beuk J, Beninger RJ, Paré M. Investigating a race model account of executive control in rats with the countermanding paradigm. Neuroscience 2014; 263:96-110. [PMID: 24440749 DOI: 10.1016/j.neuroscience.2014.01.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/16/2013] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
Abstract
The countermanding paradigm investigates the ability to withhold a response when a stop signal is presented occasionally. The race model (Logan and Cowan, 1984) was developed to account for performance in humans and to estimate the stop signal response time (SSRT). This model has yet to be fully validated for countermanding performance in rats. Furthermore, response adjustments observed in human performance of the task have not been examined in rodents. Male Wistar rats were trained to respond to a visual stimulus (go signal) by pressing a lever below that stimulus, but to countermand the lever press (25% of trials) subsequent to an auditory tone (stop signal) presented after a variable delay. We found decreased inhibitory success as stop signal delay (SSD) increased and estimated a SSRT of 157ms. As expected by the race model, response time (RT) of movements that escaped inhibition: (1) were faster than responses made in the absence of a stop signal; (2) lengthened with increasing SSD; and (3) were predictable by the race model. In addition, responses were slower after stop trial errors, suggestive of error monitoring. Amphetamine (AMPH) (0.25, 0.5mg/kg) resulted in faster go trial RTs, baseline-dependent changes in SSRT and attenuated response adjustments. These findings demonstrate that the race model of countermanding performance, applied successfully in human and nonhuman primate models, can be employed in the countermanding performance of rodents. This is the first study to reveal response adjustments and AMPH-induced alterations of response adjustments in rodent countermanding.
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Affiliation(s)
- J Beuk
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - R J Beninger
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Psychiatry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - M Paré
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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70
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Grant JE, Odlaug BL. Obsessive–compulsive spectrum and disorders of the skin. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.40] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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71
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Measuring the construct of executive control in schizophrenia: Defining and validating translational animal paradigms for discovery research. Neurosci Biobehav Rev 2013; 37:2125-40. [DOI: 10.1016/j.neubiorev.2012.04.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 03/20/2012] [Accepted: 04/03/2012] [Indexed: 11/20/2022]
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72
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Joos L, Goudriaan AE, Schmaal L, van den Brink W, Sabbe BGC, Dom G. Effect of modafinil on cognitive functions in alcohol dependent patients: a randomized, placebo-controlled trial. J Psychopharmacol 2013; 27:998-1006. [PMID: 24045883 DOI: 10.1177/0269881113503505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cognitive deficits are highly prevalent in alcohol-dependent (AD) patients and may have a detrimental impact on treatment response and treatment outcome. Enhancing cognitive functions may improve treatment success. Modafinil is a promising compound in this respect. Therefore, a randomized double-blind placebo-controlled trial was conducted with modafinil (300 mg/d) or placebo in 83 AD patients for 10 weeks. Various cognitive functions (digit span task, Tower of London task, Stroop task) were measured at baseline, during and after treatment. Compared to placebo, modafinil improved verbal short-term memory (number of forward digit spans) (p=0.030), but modafinil exerted a negative effect on the working memory score of the digit span task (p=0.003). However, subgroup analyses revealed that modafinil did improve both working memory and verbal short-term memory in AD patients with a poor working memory ability at baseline (25% worst performers), whereas no significant treatment effect of modafinil was found on these two dependent variables in patients with good working memory skills at baseline (25% best performers). No effect of modafinil was found on measures of planning (Tower of London task) and selective attention (Stroop task). Further research is needed to better understand the relationship between cognitive remediation and treatment outcome in order to design targeted treatments.
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Affiliation(s)
- Leen Joos
- 1Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Wilrijk, Belgium
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73
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A novel translational assay of response inhibition and impulsivity: effects of prefrontal cortex lesions, drugs used in ADHD, and serotonin 2C receptor antagonism. Neuropsychopharmacology 2013; 38:2150-9. [PMID: 23657439 PMCID: PMC3773664 DOI: 10.1038/npp.2013.112] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 01/25/2023]
Abstract
Animal models are making an increasing contribution to our understanding of the psychology and brain mechanisms underlying behavioral inhibition and impulsivity. The aim here was to develop, for the first time, a mouse analog of the stop-signal reaction time task with high translational validity in order to be able to exploit this species in genetic and molecular investigations of impulsive behaviors. Cohorts of mice were trained to nose-poke to presentations of visual stimuli. Control of responding was manipulated by altering the onset of an auditory 'stop-signal' during the go response. The anticipated systematic changes in action cancellation were observed as stopping was made more difficult by placing the stop-signal closer to the execution of the action. Excitotoxic lesions of medial prefrontal cortex resulted in impaired stopping, while the clinically effective drugs methylphenidate and atomoxetine enhanced stopping abilities. The specific 5-HT2C receptor antagonist SB242084 also led to enhanced response control in this task. We conclude that stop-signal reaction time task performance can be successfully modeled in mice and is sensitive to prefrontal cortex dysfunction and drug treatments in a qualitatively similar manner to humans and previous rat models. Additionally, using this model we show novel and highly discrete effects of 5-HT2C receptor antagonism that suggest manipulation of 5-HT2C receptor function may be of use in correcting maladaptive impulsive behaviors and provide further evidence for dissociable contributions of serotonergic transmission to response control.
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74
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van Kerkhof LWM, Damsteegt R, Trezza V, Voorn P, Vanderschuren LJMJ. Social play behavior in adolescent rats is mediated by functional activity in medial prefrontal cortex and striatum. Neuropsychopharmacology 2013; 38:1899-909. [PMID: 23568326 PMCID: PMC3746695 DOI: 10.1038/npp.2013.83] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/29/2013] [Accepted: 04/03/2013] [Indexed: 12/18/2022]
Abstract
Social play behavior is a characteristic, vigorous form of social interaction in young mammals. It is highly rewarding and thought to be of major importance for social and cognitive development. The neural substrates of social play are incompletely understood, but there is evidence to support a role for the prefrontal cortex (PFC) and striatum in this behavior. Using pharmacological inactivation methods, ie, infusions of GABA receptor agonists (baclofen and muscimol; B&M) or the AMPA/kainate receptor antagonist 6,7-dinitroquinoxaline-2,3(1H,4H)-dione (DNQX), we investigated the involvement of several subregions of the medial PFC and striatum in social play. Inactivation of the prelimbic cortex, infralimbic cortex, and medial/ventral orbitofrontal cortex using B&M markedly reduced frequency and duration of social play behavior. Local administration of DNQX into the dorsomedial striatum increased the frequency and duration of social play, whereas infusion of B&M tended to have the same effect. Inactivation of the nucleus accumbens (NAcc) core using B&M increased duration but not frequency of social play, whereas B&M infusion into the NAcc shell did not influence social play behavior. Thus, functional integrity of the medial PFC is important for the expression of social play behavior. Glutamatergic inputs into the dorsomedial striatum exert an inhibitory influence on social play, and functional activity in the NAcc core acts to limit the length of playful interactions. These results highlight the importance of prefrontal and striatal circuits implicated in cognitive control, decision making, behavioral inhibition, and reward-associated processes in social play behavior.
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Affiliation(s)
- Linda WM van Kerkhof
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ruth Damsteegt
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Viviana Trezza
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, Utrecht, The Netherlands,Department of Biology, University ‘Roma Tre', Rome, Italy
| | - Pieter Voorn
- Department of Anatomy and Neurosciences, Neuroscience Campus Amsterdam, VU University Medical Centre, Amsterdam, The Netherlands
| | - Louk JMJ Vanderschuren
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, Utrecht, The Netherlands,Department of Animals in Science and Society, Division of Behavioural Neuroscience, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands,Department of Animals in Science and Society, Division of Behavioural Neuroscience, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, Utrecht 3584 CM, The Netherlands, Tel: +31 30 2535239, Fax: +31 30 2537997, E-mail:
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75
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Bari A, Robbins TW. Inhibition and impulsivity: Behavioral and neural basis of response control. Prog Neurobiol 2013; 108:44-79. [DOI: 10.1016/j.pneurobio.2013.06.005] [Citation(s) in RCA: 1193] [Impact Index Per Article: 108.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/24/2013] [Accepted: 06/26/2013] [Indexed: 11/17/2022]
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76
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Working memory capacity predicts effects of methylphenidate on reversal learning. Neuropsychopharmacology 2013; 38:2011-8. [PMID: 23612436 PMCID: PMC3746683 DOI: 10.1038/npp.2013.100] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 01/15/2023]
Abstract
Increased use of stimulant medication, such as methylphenidate, by healthy college students has raised questions about its cognitive-enhancing effects. Methylphenidate acts by increasing extracellular catecholamine levels and is generally accepted to remediate cognitive and reward deficits in patients with attention deficit hyperactivity disorder. However, the cognitive-enhancing effects of such 'smart drugs' in the healthy population are still unclear. Here, we investigated effects of methylphenidate (Ritalin, 20 mg) on reward and punishment learning in healthy students (N=19) in a within-subject, double-blind, placebo-controlled cross-over design. Results revealed that methylphenidate effects varied both as a function of task demands and as a function of baseline working memory capacity. Specifically, methylphenidate improved reward vs punishment learning in high-working memory subjects, whereas it impaired reward vs punishment learning in low-working memory subjects. These results contribute to our understanding of individual differences in the cognitive-enhancing effects of methylphenidate in the healthy population. Moreover, they highlight the importance of taking into account both inter- and intra-individual differences in dopaminergic drug research.
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77
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Joos L, Goudriaan AE, Schmaal L, Fransen E, van den Brink W, Sabbe BGC, Dom G. Effect of modafinil on impulsivity and relapse in alcohol dependent patients: a randomized, placebo-controlled trial. Eur Neuropsychopharmacol 2013; 23:948-55. [PMID: 23141152 DOI: 10.1016/j.euroneuro.2012.10.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/30/2012] [Accepted: 10/05/2012] [Indexed: 11/29/2022]
Abstract
Poor impulse control plays an important role in the development, course and relapse of substance use disorders. Therefore, improving impulse control may represent a promising approach in the treatment of alcohol dependence. This study aimed to test the effect of modafinil on impulse control and alcohol use in alcohol dependent patients (ADP) in a randomized, double-blind, placebo-controlled trial. Eighty-three abstinent ADP were randomized to 10 weeks modafinil (300 mg/d) or placebo. Alcohol use was quantified using the timeline follow-back method and was assessed until 6 months after treatment discontinuation. Impulsivity was assessed using self-report questionnaires (Barratt Impulsiveness Scale; State Impulsivity questionnaire) and neurocognitive tasks (Stop Signal Task; Delay Discounting Task) administered before, during and after treatment. Modafinil significantly improved self-report measures of state impulsivity, but had no effect on percentage of abstinent days or percentage of heavy drinking days, nor on the behavioral measures of impulsivity. However, subgroup analysis revealed that modafinil prolonged the time to relapse (p=.022) and tended to increase the percentage of abstinent days (p=.066) in ADP with poor response inhibition at baseline, whereas modafinil increased the percentage of heavy drinking days (p=.003) and reduced the percentage of abstinent days (p=.002) in patients with better baseline response inhibition. Overall results do not favor the use of modafinil in order to reduce relapse or relapse severity in ADP, and caution is required in prescribing modafinil to a non-selected sample of ADP. Further research on the effect of modafinil in ADP with poor baseline response inhibition is warranted.
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Affiliation(s)
- Leen Joos
- Collaborative Antwerp Psychiatric Research Institute, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
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78
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Schmaal L, Joos L, Koeleman M, Veltman DJ, van den Brink W, Goudriaan AE. Effects of modafinil on neural correlates of response inhibition in alcohol-dependent patients. Biol Psychiatry 2013; 73:211-8. [PMID: 22858150 DOI: 10.1016/j.biopsych.2012.06.032] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 06/07/2012] [Accepted: 06/25/2012] [Indexed: 11/18/2022]
Abstract
BACKGROUND Impaired response inhibition is a key feature of patients with alcohol dependence. Improving impulse control is a promising target for the treatment of alcohol dependence. The pharmacologic agent modafinil enhances cognitive control functions in both healthy subjects and in patients with various psychiatric disorders. However, very little is known about the underlying neural correlates of improvements in response inhibition following modafinil. METHODS We conducted a randomized, double-blind, placebo-controlled, crossover study using functional magnetic resonance imaging with a stop signal task to examine effects of a single dose of modafinil (200 mg) on response inhibition and underlying neural correlates in abstinent alcohol-dependent patients (AD) (n = 16) and healthy control subjects (n = 16). RESULTS Within the AD group modafinil administration improved response inhibition (reflected by the stop signal reaction time [SSRT]) in subjects with initial poor response inhibition, whereas response inhibition was diminished in better performing subjects. In AD patients with initial poor response inhibition, modafinil-induced SSRT improvement was accompanied by greater activation in the thalamus and supplementary motor area (SMA) and reduced connectivity between the thalamus and the primary motor cortex. In addition, the relationship between baseline response inhibition and modafinil-induced SSRT improvement was mediated by these changes in thalamus and SMA activation. CONCLUSIONS These findings indicate that modafinil can improve response inhibition in alcohol-dependent patients through its effect on thalamus and SMA function but only in subjects with poor baseline response inhibition. Therefore, baseline levels of response inhibition should be taken into account when considering treatment with modafinil in AD.
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Affiliation(s)
- Lianne Schmaal
- Amsterdam Institute for Addiction Research, Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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79
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Chamberlain SR. Modafinil, inhibitory control, and alcoholism. Biol Psychiatry 2013; 73:207-8. [PMID: 23337023 DOI: 10.1016/j.biopsych.2012.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022]
Affiliation(s)
- Samuel R Chamberlain
- Department of Psychiatry, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom.
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80
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Bari A, Robbins TW. Noradrenergic versus dopaminergic modulation of impulsivity, attention and monitoring behaviour in rats performing the stop-signal task: possible relevance to ADHD. Psychopharmacology (Berl) 2013; 230:89-111. [PMID: 23681165 PMCID: PMC3824307 DOI: 10.1007/s00213-013-3141-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/29/2013] [Indexed: 01/06/2023]
Abstract
RATIONALE Deficient response inhibition is a prominent feature of many pathological conditions characterised by impulsive and compulsive behaviour. Clinically effective doses of catecholamine reuptake inhibitors are able to improve such inhibitory deficits as measured by the stop-signal task (SST) in humans and other animals. However, the precise therapeutic mode of action of these compounds in terms of their relative effects on dopamine (DA) and noradrenaline (NA) systems in prefrontal cortical and striatal regions mediating attention and cognitive control remains unclear. OBJECTIVES We sought to fractionate the effects of global catecholaminergic manipulations on SST performance by using receptor-specific compounds for NA or DA. The results are described in terms of the effects of modulating specific receptor subtypes on various behavioural measures such as response inhibition, perseveration, sustained attention, error monitoring and motivation. RESULTS Blockade of α2-adrenoceptors improved sustained attention and response inhibition, whereas α1 and β1/2 adrenergic receptor antagonists disrupted go performance and sustained attention, respectively. No relevant effects were obtained after targeting DA D1, D2 or D4 receptors, while both a D3 receptor agonist and antagonist improved post-error slowing and compulsive nose-poke behaviour, though generally impairing other task measures. CONCLUSIONS Our results suggest that the use of specific pharmacological agents targeting α2 and β noradrenergic receptors may improve existing treatments for attentional deficits and impulsivity, whereas DA D3 receptors may modulate error monitoring and perseverative behaviour.
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Affiliation(s)
- A. Bari
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of Cambridge, Cambridge, CB2 3EB UK ,Department of Neurosciences, Medical University of South Carolina, Ashley Avenue 173, BSB 409, 29425 Charleston, SC USA
| | - T. W. Robbins
- Behavioural and Clinical Neuroscience Institute and Department of Psychology, University of Cambridge, Cambridge, CB2 3EB UK
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81
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Nandam LS, Hester R, Wagner J, Dean AJ, Messer C, Honeysett A, Nathan PJ, Bellgrove MA. Dopamine D₂ receptor modulation of human response inhibition and error awareness. J Cogn Neurosci 2012; 25:649-56. [PMID: 23163418 DOI: 10.1162/jocn_a_00327] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Response inhibition, comprising action cancellation and action restraint, and error awareness are executive functions of considerable clinical relevance to neuropsychiatric disorders. Nevertheless, our understanding of their underlying catecholamine mechanisms, particularly regarding dopamine, is limited. Here, we used the dopamine D2 agonist cabergoline to study its ability to improve inhibitory control and modulate awareness of performance errors. A randomized, double-blind, placebo-controlled, crossover design with a single dose of cabergoline (1.25 mg) and placebo (dextrose) was employed in 25 healthy participants. They each performed the stop-signal task, a well-validated measure of action cancellation, and the Error Awareness Task, a go/no-go measure of action restraint and error awareness, under each drug condition. Cabergoline was able to selectively reduce stop-signal RT, compared with placebo, indicative of enhanced action cancellation (p < .05). This enhancement occurred without concomitant changes in overall response speed or RT variability and was not seen for errors of commission on the Error Awareness Task. Awareness of performance errors on the go/no-go task was, however, significantly improved by cabergoline compared with placebo (p < .05). Our results contribute to growing evidence for the dopaminergic control of distinct aspects of human executive ability, namely, action cancellation and error awareness. The findings may aid the development of new, or the repurposing of existing, pharmacotherapy that targets the cognitive dysfunction of psychiatric and neurological disorders. They also provide further evidence that specific cognitive paradigms have correspondingly specific neurochemical bases.
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82
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Tricklebank MD, Garner JP. The Possibilities and Limitations of Animal Models for Psychiatric Disorders. DRUG DISCOVERY FOR PSYCHIATRIC DISORDERS 2012. [DOI: 10.1039/9781849734943-00534] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In the search for novel treatments for psychiatric disorders, many compounds that have shown promising pharmacological properties in disease models have failed to induce benefit in patients. There is good reason to believe that the preclinical approaches routinely used in drug discovery often provide an overly optimistic picture of clinical potential. Here we discuss some of the factors that we believe lead to erroneous decision-making, including: false interpretations of the behavioural significance of drug effects in the model species; fundamental flaws in aspects of experimental design and analysis; and misconceptions about the criteria that need to be applied before a model can be said to be validated. Only by focusing on well-constructed biological hypotheses of drug action in conjunction with reliable neurochemical, electrophysiological and behavioural assays that can be demonstrated to engage clinically relevant brain circuits will the chances of clinical success be improved. As psychiatric disorders come to be viewed less descriptively and more mechanistically as developmental disorders in brain circuits, incorporating biomarkers – measured biological variables that can indicate a normal or abnormal biological etiological process – will become the essential key to improving model development and validation, and target assessment and refinement.
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Affiliation(s)
- Mark D. Tricklebank
- Lilly Centre for Cognitive Neuroscience Eli Lilly and Co. Ltd, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey GU20 6PH UK
| | - Joseph P. Garner
- Department of Comparative Medicine and, by courtesy, Department of Psychiatry and Behavioral Sciences Stanford University 287 Campus Drive, Stanford, CA 94305-5410 USA
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Economidou D, Theobald DEH, Robbins TW, Everitt BJ, Dalley JW. Norepinephrine and dopamine modulate impulsivity on the five-choice serial reaction time task through opponent actions in the shell and core sub-regions of the nucleus accumbens. Neuropsychopharmacology 2012; 37:2057-66. [PMID: 22510726 PMCID: PMC3398724 DOI: 10.1038/npp.2012.53] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Impulsive behavior is a hallmark of several neuropsychiatric disorders (eg, attention-deficit/hyperactivity disorder, ADHD). Although dopamine (DA) and norepinephrine (NE) have a significant role in the modulation of impulsivity their neural loci of action is not well understood. Here, we investigated the effects of the selective NE re-uptake inhibitor atomoxetine (ATO) and the mixed DA/NE re-uptake inhibitor methylphenidate (MPH), both with proven clinical efficacy in ADHD, on the number of premature responses on a five-choice serial reaction time task, an operational measure of impulsivity. Microinfusions of ATO into the shell, but not the core, sub-region of the nucleus accumbens (NAcb) significantly decreased premature responding whereas infusions of MPH in the core, but not the shell, sub-region significantly increased premature responding. However, neither ATO nor MPH significantly altered impulsive behavior when infused into the prelimbic or infralimbic cortices. The opposing effects of ATO and MPH in the NAcb core and shell on impulsivity were unlikely mediated by ancillary effects on behavioral activation as locomotor activity was either unaffected, as in the case of ATO infusions in the core and shell, or increased when MPH was infused into either the core and shell sub-region. These findings indicate an apparently 'opponent' modulation of premature responses by NE and DA in the NAcb shell or core, respectively, and suggest that the symptom clusters of hyperactive-impulsive type ADHD may have distinct neural and neurochemical substrates.
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Affiliation(s)
- Daina Economidou
- Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Cambridge, UK
| | - David EH Theobald
- Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Cambridge, UK
| | - Trevor W Robbins
- Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Cambridge, UK
| | - Barry J Everitt
- Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Cambridge, UK
| | - Jeffrey W Dalley
- Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Cambridge, UK,Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK,Behavioral and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge, Cambridgeshire, CB2 3EB, UK. Tel: +44(1223) 765 291, Fax: +44(1223) 333 564, E-mail:
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84
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Moschak TM, Stang KA, Phillips TJ, Mitchell SH. Behavioral inhibition in mice bred for high vs. low levels of methamphetamine consumption or sensitization. Psychopharmacology (Berl) 2012; 222:353-65. [PMID: 22311384 PMCID: PMC3383918 DOI: 10.1007/s00213-012-2650-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 01/23/2012] [Indexed: 02/07/2023]
Abstract
RATIONALE Research indicates that genetics influence methamphetamine self-administration as well as sensitization to the psychomotor-stimulating effects of methamphetamine (MA). Other studies have suggested that heightened levels of impulsivity, including low levels of behavioral inhibition, are associated with the use of drugs, including MA. OBJECTIVES The current study examined whether lines of mice selected for traits associated with a heightened risk of developing MA dependence would also exhibit low levels of drug-naïve inhibition and whether administration of MA would result in different levels of inhibition in animals selected to consume or respond more to MA. METHODS A go/no-go task was used to assess inhibition in male and female mice selected for low or high levels of MA consumption or selected for high or low levels of locomotor sensitization to repeated injections of MA. RESULTS Mice selected for MA sensitization differed in false alarms, precue response rates (measures of behavioral inhibition), and also hits (measure of operant responding). Mice selected for MA consumption did not differ in measures of behavioral inhibition, though hits differed. When MA was administered prior to the task, false alarms, precue response rates, and hits decreased for mice from all selected lines. Female high drinking mice were particularly resistant to MA's effects on hits, but not precue response rate or false alarms. CONCLUSIONS These data suggest a shared, but complex, genetic association between inhibition processes, general levels of operant responding, and MA sensitization or consumption.
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Affiliation(s)
- Travis M. Moschak
- Department of Behavioral Neuroscience, Oregon Health & Science University
| | - Katherine A. Stang
- Department of Behavioral Neuroscience, Oregon Health & Science University
| | - Tamara J. Phillips
- Department of Behavioral Neuroscience, Oregon Health & Science University,Methamphetamine Abuse Research Center, Oregon Health & Science University,Portland Veterans Affairs Medical Center
| | - Suzanne H. Mitchell
- Department of Behavioral Neuroscience, Oregon Health & Science University,Department of Psychiatry Oregon Health & Science University,Methamphetamine Abuse Research Center, Oregon Health & Science University
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85
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Dalley JW, Roiser JP. Dopamine, serotonin and impulsivity. Neuroscience 2012; 215:42-58. [PMID: 22542672 DOI: 10.1016/j.neuroscience.2012.03.065] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 03/08/2012] [Accepted: 03/10/2012] [Indexed: 12/17/2022]
Abstract
Impulsive people have a strong urge to act without thinking. It is sometimes regarded as a positive trait but rash impulsiveness is also widely present in clinical disorders such as attention deficit hyperactivity disorder (ADHD), drug dependence, mania, and antisocial behaviour. Contemporary research has begun to make major inroads into unravelling the brain mechanisms underlying impulsive behaviour with a prominent focus on the limbic cortico-striatal systems. With this progress has come the understanding that impulsivity is a multi-faceted behavioural trait involving neurally and psychologically diverse elements. We discuss the significance of this heterogeneity for clinical disorders expressing impulsive behaviour and the pivotal contribution made by the brain dopamine and serotonin systems in the aetiology and treatment of behavioural syndromes expressing impulsive symptoms.
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Affiliation(s)
- J W Dalley
- Behavioural and Clinical Neuroscience Institute and Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK. jwd20@cam. ac. uk
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86
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Winstanley CA. The utility of rat models of impulsivity in developing pharmacotherapies for impulse control disorders. Br J Pharmacol 2012; 164:1301-21. [PMID: 21410459 DOI: 10.1111/j.1476-5381.2011.01323.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
High levels of impulsive behaviours are a clinically significant symptom in a range of psychiatric disorders, such as attention deficit hyperactivity disorder, bipolar disorder, personality disorders, pathological gambling and substance abuse. Although often measured using questionnaire assessments, levels of different types of impulsivity can also be determined using behavioural tests. Rodent analogues of these paradigms have been developed, and similar neural circuitry has been implicated in their performance in both humans and rats. In the current review, the methodology underlying the measurement of different aspects of impulsive action and choice are considered from the viewpoint of drug development, with a focus on the continuous performance task (CPT), stop-signal task (SST), go/no-go and delay-discounting paradigms. Current issues impeding translation between animal and human studies are identified, and comparisons drawn between the acute effects of dopaminergic, noradrenergic and serotonergic compounds across species. Although the field could benefit from a more systematic determination of different pharmacological agents across paradigms, there are signs of strong concordance between the animal and human data. However, the type of impulsivity measured appears to play a significant role, with the SST and delay discounting providing more consistent effects for dopaminergic drugs, while the CPT and SST show better predictive validity so far for serotonergic and noradrenergic compounds. Based on the available data, it would appear that these impulsivity models could be used more widely to identify potential pharmacotherapies for impulse control disorders. Novel targets within the glutamatergic and serotonergic system are also suggested.
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87
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Fineberg NA, Chamberlain SR, Hollander E, Boulougouris V, Robbins TW. Translational approaches to obsessive-compulsive disorder: from animal models to clinical treatment. Br J Pharmacol 2012; 164:1044-61. [PMID: 21486280 DOI: 10.1111/j.1476-5381.2011.01422.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Obsessive-compulsive disorder (OCD) is characterized by obsessions (intrusive thoughts) and compulsions (repetitive ritualistic behaviours) leading to functional impairment. Accumulating evidence links these conditions with underlying dysregulation of fronto-striatal circuitry and monoamine systems. These abnormalities represent key targets for existing and novel treatment interventions. However, the brain bases of these conditions and treatment mechanisms are still not fully elucidated. Animal models simulating the behavioural and clinical manifestations of the disorder show great potential for augmenting our understanding of the pathophysiology and treatment of OCD. This paper provides an overview of what is known about OCD from several perspectives. We begin by describing the clinical features of OCD and the criteria used to assess the validity of animal models of symptomatology; namely, face validity (phenomenological similarity between inducing conditions and specific symptoms of the human phenomenon), predictive validity (similarity in response to treatment) and construct validity (similarity in underlying physiological or psychological mechanisms). We then survey animal models of OC spectrum conditions within this framework, focusing on (i) ethological models; (ii) genetic and pharmacological models; and (iii) neurobehavioural models. We also discuss their advantages and shortcomings in relation to their capacity to identify potentially efficacious new compounds. It is of interest that there has been rather little evidence of 'false alarms' for therapeutic drug effects in OCD models which actually fail in the clinic. While it is more difficult to model obsessive cognition than compulsive behaviour in experimental animals, it is feasible to infer cognitive inflexibility in certain animal paradigms. Finally, key future neurobiological and treatment research areas are highlighted.
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Affiliation(s)
- N A Fineberg
- National OCDs Treatment Service, Hertfordshire Partnership NHS Foundation Trust, Welwyn Garden City, UK.
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88
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Hunsaker MR. Comprehensive neurocognitive endophenotyping strategies for mouse models of genetic disorders. Prog Neurobiol 2012; 96:220-41. [PMID: 22266125 PMCID: PMC3289520 DOI: 10.1016/j.pneurobio.2011.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 12/06/2011] [Accepted: 12/20/2011] [Indexed: 01/21/2023]
Abstract
There is a need for refinement of the current behavioral phenotyping methods for mouse models of genetic disorders. The current approach is to perform a behavioral screen using standardized tasks to define a broad phenotype of the model. This phenotype is then compared to what is known concerning the disorder being modeled. The weakness inherent in this approach is twofold: First, the tasks that make up these standard behavioral screens do not model specific behaviors associated with a given genetic mutation but rather phenotypes affected in various genetic disorders; secondly, these behavioral tasks are insufficiently sensitive to identify subtle phenotypes. An alternate phenotyping strategy is to determine the core behavioral phenotypes of the genetic disorder being studied and develop behavioral tasks to evaluate specific hypotheses concerning the behavioral consequences of the genetic mutation. This approach emphasizes direct comparisons between the mouse and human that facilitate the development of neurobehavioral biomarkers or quantitative outcome measures for studies of genetic disorders across species.
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Affiliation(s)
- Michael R Hunsaker
- Department of Neurological Surgery, University of California, Davis, Davis, CA 95616, USA.
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89
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Abstract
Cognitive dysfunction is a core aspect of schizophrenia that constitutes a major obstacle toward reintegration of patients into society. Although multiple cognitive deficits are evident in schizophrenia patients, no medication is currently approved for their amelioration. Although consensus clinical test batteries have been developed for the assessment of putative cognition enhancers in patients with schizophrenia, parallel animal tests remain to be validated. Having no approved treatment for cognitive symptoms means no positive control can be used to examine pharmacological predictive validity of animal models. Thus, focus has been placed on animal paradigms that have demonstrable construct validity for the cognitive domain being assessed.This review describes the growing arsenal of animal paradigms under development that have putative construct validity to cognitive domains affected in schizophrenia. We discuss (1) the construct validity of the paradigms; (2) compounds developed to investigate putative treatment targets; and (3) manipulations used to first impair task performance. Focus is placed on the paradigm design, including how the use of multivariate assessments can provide evidence that main effects of treatment are not confounded by extraneous effects.
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90
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Grégoire S, Rivalan M, Le Moine C, Dellu-Hagedorn F. The synergy of working memory and inhibitory control: behavioral, pharmacological and neural functional evidences. Neurobiol Learn Mem 2011; 97:202-12. [PMID: 22197651 DOI: 10.1016/j.nlm.2011.12.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/28/2011] [Accepted: 12/05/2011] [Indexed: 01/09/2023]
Abstract
Concomitant deficits in working memory and behavioral inhibition in several psychiatric disorders like attention-deficit/hyperactivity disorder, addiction or mania, suggest that common brain mechanisms may underlie their etiologies. Based on the theoretical assumption that a continuum exists between health and mental disorders, we explored the relationship between working memory and inhibition in healthy individuals, through spontaneous inter individual differences in behavior, and tested the hypothesis of a functional link through the fronto-striatal dopaminergic system. Rats were classified into three groups, showing good, intermediate and poor working memory and were compared for their inhibitory abilities. These two functions were simultaneously modulated by a dose-effect of d-amphetamine and in situ hybridization was used to quantify dopaminergic receptor (RD1) mRNAs in prefrontal cortex and striatal areas. A functional relationship between working memory and inhibition abilities was revealed. Both functions were similarly modulated by d-amphetamine according to an inverted-U shaped relationship and depending on initial individual performances. D-amphetamine selectively improved working memory and inhibition of poor and intermediate performers at low doses whereas it impaired both processes in good performers at a higher dose. D1 receptors were less expressed in prelimbic, infralimbic and anterior cingulate cortices of good compared to intermediate and poor performers, whereas no difference was observed between groups in striatal areas. The synergy of working memory and inhibitory abilities, observed in both healthy and psychiatric populations, may originate from endogenous variability in dopaminergic prefrontal cortex activity. Such findings confirm the validity of a dimensional approach, based on the concept of continuity between health and mental disorders for identifying endophenotypes of mental disorders.
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Affiliation(s)
- Stéphanie Grégoire
- CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France; Univ. Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France.
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91
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Zandbelt BB, van Buuren M, Kahn RS, Vink M. Reduced proactive inhibition in schizophrenia is related to corticostriatal dysfunction and poor working memory. Biol Psychiatry 2011; 70:1151-8. [PMID: 21903198 DOI: 10.1016/j.biopsych.2011.07.028] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 12/27/2022]
Abstract
BACKGROUND Inhibitory control is central to executive functioning and appears deficient in schizophrenia. However, it is unclear how inhibitory control is affected, what the underlying neural mechanisms are, whether these deficits are related to the illness itself or to increased risk for the illness, and whether there is a relation to impairments in other executive functions. METHODS We used functional magnetic resonance imaging to investigate two forms of inhibitory control: proactive inhibition (anticipation of stopping) and reactive inhibition (outright stopping). Twenty-four schizophrenia patients, 24 unaffected siblings, and 24 healthy control subjects performed a modified version of the stop-signal paradigm. To assess the relation between performance on inhibitory control and other executive functions, we correlated inhibitory control indices with working memory span. RESULTS Compared with control subjects, proactive inhibition was reduced in patients and siblings. Reactive inhibition was unaffected. Reduced proactive inhibition was associated with a failure to activate the right striatum, the right inferior frontal cortex, and the left and right temporoparietal junction. Activation during reactive inhibition was unaffected. Those patients with the least proactive inhibition also showed the shortest working memory span. CONCLUSIONS These results suggest that schizophrenia is associated with reduced proactive inhibition, probably resulting from corticostriatal dysfunction. This deficit is related to an increased risk for schizophrenia and likely reflects a general executive function deficit rather than a specific inhibitory control impairment.
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Affiliation(s)
- Bram B Zandbelt
- Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, The Netherlands.
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92
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Humby T, Wilkinson LS. Assaying dissociable elements of behavioural inhibition and impulsivity: translational utility of animal models. Curr Opin Pharmacol 2011; 11:534-9. [DOI: 10.1016/j.coph.2011.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 06/06/2011] [Accepted: 06/10/2011] [Indexed: 11/30/2022]
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93
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Abstract
Defining the neural and neurochemical substrates of response inhibition is of crucial importance for the study and treatment of pathologies characterized by impulsivity such as attention-deficit/hyperactivity disorder and addiction. The stop-signal task (SST) is one of the most popular paradigms used to study the speed and efficacy of inhibitory processes in humans and other animals. Here we investigated the effect of temporarily inactivating different prefrontal subregions in the rat by means of muscimol microinfusions on SST performance. We found that dorsomedial prefrontal cortical areas are important for inhibiting an already initiated response. We also investigated the possible neural substrates of the selective noradrenaline reuptake inhibitor atomoxetine via its local microinfusion into different subregions of the rat prefrontal cortex. Our results show that both orbitofrontal and dorsal prelimbic cortices mediate the beneficial effects of atomoxetine on SST performance. To assess the neurochemical specificity of these effects, we infused the α2-adrenergic agonist guanfacine and the D(1)/D(2) antagonist α-flupenthixol in dorsal prelimbic cortex to interfere with noradrenergic and dopaminergic neurotransmission, respectively. Guanfacine, which modulates noradrenergic neurotransmission, selectively impaired stopping, whereas blocking dopaminergic receptors by α-flupenthixol infusion prolonged go reaction time only, confirming the important role of noradrenergic neurotransmission in response inhibition. These results show that, similar to humans, distinct networks play important roles during SST performance in the rat and that they are differentially modulated by noradrenergic and dopaminergic neurotransmission. This study advances our understanding of the neuroanatomical and neurochemical determinants of impulsivity, which are relevant for a range of psychiatric disorders.
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94
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Sigurgeirsson B, þorsteinsson H, Arnardóttir H, Jóhannesdóttir IÞ, Karlsson KÆ. Effects of Modafinil on Sleep–Wake Cycles in Larval Zebrafish. Zebrafish 2011; 8:133-40. [DOI: 10.1089/zeb.2011.0708] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Benjamín Sigurgeirsson
- Department of Biomedical Engineering, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland
| | - Haraldur þorsteinsson
- Department of Biomedical Engineering, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland
| | - Hrönn Arnardóttir
- Department of Biomedical Engineering, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland
| | - Ingibjörg þ. Jóhannesdóttir
- Department of Biomedical Engineering, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland
| | - Karl Ægir Karlsson
- Department of Biomedical Engineering, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland
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95
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Barak S, Weiner I. Putative cognitive enhancers in preclinical models related to schizophrenia: The search for an elusive target. Pharmacol Biochem Behav 2011; 99:164-89. [DOI: 10.1016/j.pbb.2011.03.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/27/2011] [Accepted: 03/12/2011] [Indexed: 12/12/2022]
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96
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Brenhouse HC, Andersen SL. Developmental trajectories during adolescence in males and females: a cross-species understanding of underlying brain changes. Neurosci Biobehav Rev 2011; 35:1687-703. [PMID: 21600919 PMCID: PMC3134153 DOI: 10.1016/j.neubiorev.2011.04.013] [Citation(s) in RCA: 251] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 04/14/2011] [Accepted: 04/21/2011] [Indexed: 11/20/2022]
Abstract
Adolescence is a transitional period between childhood and adulthood that encompasses vast changes within brain systems that parallel some, but not all, behavioral changes. Elevations in emotional reactivity and reward processing follow an inverted U shape in terms of onset and remission, with the peak occurring during adolescence. However, cognitive processing follows a more linear course of development. This review will focus on changes within key structures and will highlight the relationships between brain changes and behavior, with evidence spanning from functional magnetic resonance imaging (fMRI) in humans to molecular studies of receptor and signaling factors in animals. Adolescent changes in neuronal substrates will be used to understand how typical and atypical behaviors arise during adolescence. We draw upon clinical and preclinical studies to provide a neural framework for defining adolescence and its role in the transition to adulthood.
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Affiliation(s)
- Heather C. Brenhouse
- Laboratory of Developmental Neuropharmacology McLean Hospital and Department of Psychiatry, Harvard Medical School
| | - Susan L. Andersen
- Laboratory of Developmental Neuropharmacology McLean Hospital and Department of Psychiatry, Harvard Medical School
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97
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Obeso I, Wilkinson L, Jahanshahi M. Levodopa medication does not influence motor inhibition or conflict resolution in a conditional stop-signal task in Parkinson’s disease. Exp Brain Res 2011; 213:435-45. [DOI: 10.1007/s00221-011-2793-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 07/02/2011] [Indexed: 10/17/2022]
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98
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Chamberlain SR, Robbins TW, Winder-Rhodes S, Müller U, Sahakian BJ, Blackwell AD, Barnett JH. Translational approaches to frontostriatal dysfunction in attention-deficit/hyperactivity disorder using a computerized neuropsychological battery. Biol Psychiatry 2011; 69:1192-203. [PMID: 21047621 DOI: 10.1016/j.biopsych.2010.08.019] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/10/2010] [Accepted: 08/11/2010] [Indexed: 01/28/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a prevalent condition associated with cognitive dysfunction. The Cambridge Neuropsychological Test Automated Battery is a computerized set of tests that has been widely used in ADHD and in translation/back-translation. Following a survey of translational research relevant to ADHD in experimental animals, a comprehensive literature review was conducted of studies that had used core Cambridge Neuropsychological Test Automated Battery tests 1) to evaluate cognitive dysfunction in ADHD and 2) to evaluate effects of salient drugs in patients and in volunteers. Meta-analysis was conducted where four or more independent datasets were available. Meta-analysis revealed medium-large decrements in ADHD for response inhibition (d = .790, p < .001), working memory (d = .883, p < .001), executive planning (d = .491, p < .001), and a small decrement in attentional set shifting (d = .160, p = .040). Qualitative review of the literature showed some consistent patterns. In ADHD, methylphenidate improved working memory, modafinil improved planning, and methylphenidate, modafinil, and atomoxetine improved inhibition. Meta-analysis of modafinil healthy volunteer studies showed no effects on sustained attention or set shifting. Results were paralleled by findings in experimental animals on comparable tests, enabling further analysis of drug mechanisms. Substantial cognitive deficits are present in ADHD, which can be remediated somewhat with current medications and which can readily be modeled in experimental animals using back-translational methodology. The findings suggest overlapping but also distinct early cognitive effects of ADHD medications and have important implications for understanding the pathophysiology of ADHD and for future trials.
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Affiliation(s)
- Samuel R Chamberlain
- Department of Psychiatry and Medical Research Council/Wellcome Trust Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom.
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Barnes JJM, Dean AJ, Nandam LS, O'Connell RG, Bellgrove MA. The molecular genetics of executive function: role of monoamine system genes. Biol Psychiatry 2011; 69:e127-43. [PMID: 21397212 DOI: 10.1016/j.biopsych.2010.12.040] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/25/2010] [Accepted: 12/17/2010] [Indexed: 12/20/2022]
Abstract
Executive control processes, such as sustained attention, response inhibition, and error monitoring, allow humans to guide behavior in appropriate, flexible, and adaptive ways. The consequences of executive dysfunction for humans can be dramatic, as exemplified by the large range of both neurologic and neuropsychiatric disorders in which such deficits negatively affect outcome and quality of life. Much evidence suggests that many clinical disorders marked by executive deficits are highly heritable and that individual differences in quantitative measures of executive function are strongly driven by genetic differences. Accordingly, intense research effort has recently been directed toward mapping the genetic architecture of executive control processes in both clinical (e.g., attention-deficit/hyperactivity disorder) and nonclinical populations. Here we review the extant literature on the molecular genetic correlates of three exemplar but dissociable executive functions: sustained attention, response inhibition, and error processing. Our review focuses on monoaminergic gene variants given the strong body of evidence from cognitive neuroscience and pharmacology implicating dopamine, noradrenaline, and serotonin as neuromodulators of executive function. Associations between DNA variants of the dopamine beta hydroxylase gene and measures of sustained attention accord well with cognitive-neuroanatomical models of sustained attention. Equally, functional variants of the dopamine D2 receptor gene are reliably associated with performance monitoring, error processing, and reinforcement learning. Emerging evidence suggests that variants of the dopamine transporter gene (DAT1) and dopamine D4 receptor gene (DRD4) show promise for explaining significant variance in individual differences in both behavioral and neural measures of inhibitory control.
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Affiliation(s)
- Jessica J M Barnes
- Queensland Brain Institute and School of Psychology, University of Queensland, Brisbane, Australia
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100
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Kirshenbaum AP, Jackson ER, Brown SJ, Fuchs JR, Miltner BC, Doughty AH. Nicotine-induced impulsive action: sensitization and attenuation by mecamylamine. Behav Pharmacol 2011; 22:207-21. [PMID: 21448062 PMCID: PMC3151674 DOI: 10.1097/fbp.0b013e328345ca1c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A conjunctive variable-interval differential-reinforcement-of-low-rate (VI-DRL, n=18) responding schedule and a stop-signal task (n=18) were used to evaluate the disinhibiting effects of nicotine on response withholding in rats. Sucrose solution was used to reinforce responding, and after a stable baseline was achieved under saline-administration conditions, 0.3 mg/kg nicotine was delivered before each session. Experiment 1 showed that repeated, but not the initial, administration of nicotine decreased performance on both tasks, and the effect of sensitization followed a similar timeline; 10 consecutive doses resulted in poorer proportion-correct VI-DRL trials and percent correct stop trials than the initial dose of nicotine. Furthermore, sensitization to 0.3 mg/kg nicotine decreased performance regardless of whether a spaced or consecutive-dosing regimen was followed. Experiment 2 was designed to test whether mecamylamine hydrochloride (0.1-1.0 mg/kg) could attenuate the effects of repeated 0.3 mg/kg nicotine administration, and the degree to which mecamylamine attenuation of the effect of nicotine to produce impulsive action was relative to dose. Results from experiment 2 showed that response disinhibition, as evaluated using the VI-DRL and stop-signal tasks, is related in a systematic manner to nicotinic-acetylcholine receptor activation.
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Affiliation(s)
- Ari P Kirshenbaum
- Saint Michael's College, Krikstone Lab for the Behavioral Sciences, Colchester, Vermont 05443, USA.
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