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Dopamine and working memory

Annekathrin Widmann, Marc Artinger, Lukas Biesinger, Kathrin Boepple, Christina Peters, Jana Schlechter, Mareike Selcho, Andreas S Thum
Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes-besides other forms-a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches...
October 2016: PLoS Genetics
Denise M Werchan, Anne G E Collins, Michael J Frank, Dima Amso
: Recent research indicates that adults and infants spontaneously create and generalize hierarchical rule sets during incidental learning. Computational models and empirical data suggest that, in adults, this process is supported by circuits linking prefrontal cortex (PFC) with striatum and their modulation by dopamine, but the neural circuits supporting this form of learning in infants are largely unknown. We used near-infrared spectroscopy to record PFC activity in 8-month-old human infants during a simple audiovisual hierarchical-rule-learning task...
October 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Gabriëlla A M Blokland, Angus K Wallace, Narelle K Hansell, Paul M Thompson, Ian B Hickie, Grant W Montgomery, Nicholas G Martin, Katie L McMahon, Greig I de Zubicaray, Margaret J Wright
In a population-based genome-wide association (GWA) study of n-back working memory task-related brain activation, we extracted the average percent BOLD signal change (2-back minus 0-back) from 46 regions-of-interest (ROIs) in functional MRI scans from 863 healthy twins and siblings. ROIs were obtained by creating spheres around group random effects analysis local maxima, and by thresholding a voxel-based heritability map of working memory brain activation at 50%. Quality control for test-retest reliability and heritability of ROI measures yielded 20 reliable (r>0...
September 23, 2016: International Journal of Psychophysiology
Catherine E Myers, Janice Rego, Paul Haber, Kirsten Morley, Kevin D Beck, Lee Hogarth, Ahmed A Moustafa
This study adapts a widely-used acquired equivalence paradigm to investigate how opioid-addicted individuals learn from positive and negative feedback, and how they generalize this learning. The opioid-addicted group consisted of 33 participants with a history of heroin dependency currently in a methadone maintenance program; the control group consisted of 32 healthy participants without a history of drug addiction. All participants performed a novel variant of the acquired equivalence task, where they learned to map some stimuli to correct outcomes in order to obtain reward, and to map other stimuli to correct outcomes in order to avoid punishment; some stimuli were implicitly "equivalent" in the sense of being paired with the same outcome...
September 15, 2016: Behavioural Brain Research
Brian Greeley, Rachael D Seidler
The neurobiological theory of positive affect proposes that positive mood states may benefit cognitive performance due to an increase of dopamine throughout the brain. However, the results of many positive affect studies are inconsistent; this may be due to individual differences. The relationship between dopamine and performance is not linear, but instead follows an inverted "U" shape. Given this, we hypothesized that individuals with high working memory capacity, a proxy measure for dopaminergic transmission, would not benefit from positive mood induction and in fact performance in dopamine-mediated tasks would decline...
September 12, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Kun Cheng Liu, Jun Yi Li, Wen Xie, Li Bo Li, Jin Zhang, Cheng Xue Du, Yu Ming Zhang, Hui Hui Tan, Hui Sheng Wang, Li Zhang
The role of dorsal hippocampus (DH) serotonin6 (5-HT6) receptors in memory is unknown, particularly in memory impairment of Parkinson's disease. We tested here effects of activation and blockade of DH 5-HT6 receptors on working and hippocampus-dependent memories in rats with unilateral 6-hydroxydopamine lesions of the medial forebrain bundle. The lesion induced working and hippocampus-dependent memory impairments as measured by the T-maze rewarded alternation and hole-board tests, and decreased dopamine (DA) levels in the striatum, medial prefrontal cortex (mPFC), DH and amygdala...
November 1, 2016: Brain Research
Bruce Steinberg, Kenneth Blum, Thomas McLaughlin, Joel Lubar, Marcelo Febo, Eric R Braverman, Rajendra D Badgaiyan
Attention Deficit-Hyperactivity Disorder (ADHD) often continues into adulthood. Recent neuroimaging studies found lowered baseline dopamine tone in the brains of affected individuals that may place them at risk for Substance Use Disorder (SUD). This is an observational case study of the potential for novel management of Adult ADHD with a non-addictive glutaminergic-dopaminergic optimization complex KB200z. Low-resolution electromagnetic tomography (LORETA) was used to evaluate the effects of KB220z on a 72-year-old male with ADHD, at baseline and one hour following administration...
2016: Open Journal of Clinical & Medical Case Reports
Torben Ott, Andreas Nieder
Working memory is associated with persistent activity in the prefrontal cortex (PFC). The neuromodulator dopamine, which is released by midbrain neurons projecting into the frontal lobe, influences PFC neurons and networks via the dopamine D1 (D1R) and the D2 receptor (D2R) families. Although behavioral, clinical and computational evidence suggest an involvement of D2Rs in working memory, a neuronal explanation is missing. We report an enhancement of persistent working memory responses of PFC neurons after iontophoretically stimulating D2Rs in monkeys memorizing the number of items in a display...
September 2, 2016: Cerebral Cortex
Kanwar Virdee, Jiska Kentrop, Bianca Jupp, Bethany Venus, Daniel Hensman, Simon McArthur, James Wilkinson, Trevor W Robbins, Glenda Gillies, Jeffrey W Dalley
RATIONALE: Antenatal exposure to the glucocorticoid dexamethasone dramatically increases the number of mesencephalic dopaminergic neurons in rat offspring. However, the consequences of this expansion in midbrain dopamine (DA) neurons for behavioural processes in adulthood are poorly understood, including working memory that depends on DA transmission in the prefrontal cortex (PFC). OBJECTIVES: We therefore investigated the influence of antenatal glucocorticoid treatment (AGT) on the modulation of spatial working memory by a D1 receptor agonist and on D1 receptor binding and DA content in the PFC and striatum...
October 2016: Psychopharmacology
A Weinstein, A Livny-Ezer, A Weizman
Cannabis is the most widely used illicit drug worldwide. Regular cannabis use has been associated with a range of acute and chronic mental health problems, such as anxiety, depression, psychotic symptoms and neurocognitive impairments and their neural mechanisms need to be examined. This review summarizes and critically evaluates brain-imaging studies of cannabis in recreational and regular cannabis users between January 2000 and January 2016. The search has yielded eligible 103 structural and functional studies...
August 22, 2016: Current Pharmaceutical Design
Patrick D Gajewski, Michael Falkenstein, Jan G Hengstler, Klaus Golka
Toxoplasma gondii is one of the most widespread infections in humans. Recent studies give evidence for memory deficits in infected older adults. To investigate working memory dysfunction in infected elderly, a double-blinded electrophysiological study was conducted. 84 persons derived from a sample of 131 healthy participants with the mean age of 70 years were assigned to two groups of 42 non-infected and 42 infected individuals. The outcome measures were behavioral performance, target and response-related ERPs, and time-frequency wavelets during performance in a n-back working-memory task...
October 2016: Biological Psychology
Ion Udriştoiu, Ileana Marinescu, Mihail Cristian Pîrlog, Felicia Militaru, Tudor Udriştoiu, Dragoş Marinescu, Mihai Mutică
INTRODUCTION: Schizophrenia is the most severe psychiatric illness, with a biological support in the brain. There is evidence that the adequate dopamine balance in the frontal cortex is associated with a better outcome of the disorder, while the alteration of dopamine mechanism at this level may affect the vascular system leading to secondary neuronal alterations. Our study was conducted post-mortem and its objective was to identify the alterations in the neuronal architecture, in the integrity of the microvascular unit in the frontal cortex of patients treated with potent and excessive D2-blocking antipsychotics...
2016: Romanian Journal of Morphology and Embryology, Revue Roumaine de Morphologie et Embryologie
Roshan Cools
Cognitive control helps us attain our goals by resisting distraction and temptations. Dopaminergic drugs are well known to enhance cognitive control. However, there is great variability in the effects of dopaminergic drugs across different contexts, with beneficial effects on some tasks but detrimental effects on other tasks. The mechanisms underlying this variability across cognitive task demands remain unclear. I aim to elucidate this across-task variability in dopaminergic drug efficacy by going beyond classic models that emphasize the importance of dopamine in the prefrontal cortex for cognitive control and working memory...
September 2016: Wiley Interdisciplinary Reviews. Cognitive Science
Aaron Kucinski, Inge E M de Jong, Martin Sarter
Falls are a leading cause of death in the elderly and, in a majority of patients with Parkinson's disease (PD), the leading levodopa-insensitive cause of hospitalization and long-term care. Falling in PD has been attributed to degeneration of forebrain cholinergic neurons that, in interaction with striatal dopamine losses, impairs the cognitive control of balance, gait, and movement. We previously established an animal model of these dual cholinergic-dopaminergic losses ("DL rats") and a behavioral test system (Michigan Complex Motor Control Task, MCMCT) to measure falls associated with traversing dynamic surfaces and distractors...
July 29, 2016: European Journal of Neuroscience
Mona Buhusi, Kaitlin Olsen, Benjamin Z Yang, Catalin V Buhusi
Maladaptive reactivity to stress is linked to improper decision making, impulsivity, and discounting of delayed rewards. Chronic unpredictable stress (CUS) alters dopaminergic function, re-shapes dopaminergic circuits in key areas involved in decision making, and impairs prefrontal-cortex dependent response inhibition and working memory. Glial-derived neurotrophic factor (GDNF) is essential for regulating dopamine (DA) release in the basal ganglia and for the survival of dopaminergic neurons; GDNF-deficient mice are considered an animal model for aging-related Parkinsonism...
2016: Frontiers in Behavioral Neuroscience
Crystal Meehan, Lauren Harms, Jade D Frost, Rafael Barreto, Juanita Todd, Ulrich Schall, Cynthia Shannon Weickert, Katerina Zavitsanou, Patricia T Michie, Deborah M Hodgson
Maternal exposure to infectious agents during gestation has been identified as a significant risk factor for schizophrenia. Using a mouse model, past work has demonstrated that the gestational timing of the immune-activating event can impact the behavioural phenotype and expression of dopaminergic and glutamatergic neurotransmission markers in the offspring. In order to determine the inter-species generality of this effect to rats, another commonly used model species, the current study investigated the impact of a viral mimetic Poly (I:C) at either an early (gestational day 10) or late (gestational day 19) time-point on schizophrenia-related behaviour and neurotransmitter receptor expression in rat offspring...
July 14, 2016: Brain, Behavior, and Immunity
Lorenza S Colzato, Laura Steenbergen, Roberta Sellaro, Ann-Kathrin Stock, Larissa Arning, Christian Beste
l-Tyrosine (TYR), the precursor of dopamine (DA), has been shown to enhance facets of cognitive control in situations with high cognitive demands. However some previous outcomes were mixed: some studies reported significant improvements, while other did not. Given that TYR increases DA level in the brain, we investigated, in a double-blind, randomized, placebo-controlled design, whether the C957T genotypes of a functional synonymous polymorphism in the human dopamine D2 receptor (DRD2) gene (rs6277) contribute to individual differences in the reactivity to TYR administration and whether this factor predicts the magnitude of TYR-induced performance differences on inhibiting behavioral responses in a stop-signal task and working memory (WM) updating in a N-back task...
September 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Takuya Isomura, Koji Sakai, Kiyoshi Kotani, Yasuhiko Jimbo
The free-energy principle is a candidate unified theory for learning and memory in the brain that predicts that neurons, synapses, and neuromodulators work in a manner that minimizes free energy. However, electrophysiological data elucidating the neural and synaptic bases for this theory are lacking. Here, we propose a novel theory bridging the information-theoretical principle with the biological phenomenon of spike-timing dependent plasticity (STDP) regulated by neuromodulators, which we term mSTDP. We propose that by integrating an mSTDP equation, we can obtain a form of Friston's free energy (an information-theoretical function)...
September 2016: Neural Computation
Joshua L Roffman, Alexandra S Tanner, Hamdi Eryilmaz, Anais Rodriguez-Thompson, Noah J Silverstein, New Fei Ho, Adam Z Nitenson, Daniel B Chonde, Douglas N Greve, Anissa Abi-Dargham, Randy L Buckner, Dara S Manoach, Bruce R Rosen, Jacob M Hooker, Ciprian Catana
Local prefrontal dopamine signaling supports working memory by tuning pyramidal neurons to task-relevant stimuli. Enabled by simultaneous positron emission tomography-magnetic resonance imaging (PET-MRI), we determined whether neuromodulatory effects of dopamine scale to the level of cortical networks and coordinate their interplay during working memory. Among network territories, mean cortical D1 receptor densities differed substantially but were strongly interrelated, suggesting cross-network regulation. Indeed, mean cortical D1 density predicted working memory-emergent decoupling of the frontoparietal and default networks, which respectively manage task-related and internal stimuli...
June 2016: Science Advances
Ming Li
Antipsychotic sensitization and tolerance refer to the increased and decreased drug effects due to past drug use, respectively. Both effects reflect the long-term impacts of antipsychotic treatment on the brain and result from the brain's adaptive response to the foreign property of the drug. In this review, clinical evidence of the behavioral aspect of antipsychotic sensitization and tolerance is selectively reviewed, followed by an overview of preclinical literature that examines these behavioral characteristics and the related pharmacological and nonpharmacological factors...
August 2016: Journal of Psychopharmacology
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