Delayed Matching-to-sample Research Articles

Reversible dyscognition in patients with a unilateral, middle fossa arachnoid cyst revealed by using a laptop based neuropsychological test battery (CANTAB)

The aim of this study was to evaluate and validate the Cambridge Neuropsychological Test Automated Battery (CANTAB) in a Norwegian group of patients undergoing surgery for middle fossa arachnoid cysts (AC). We also wanted to assess health related quality of life (HRQOL) in these patients to see if it could be improved by decompression of the AC. Adult patients (>18years) with unilateral middle fossa AC and no previous history of neurological disease, head injury, or a psychiatric disorder were eligible for inclusion. We used four tests from CANTAB to assess the level of neuropsychological performance: paired associate learning (PAL) and delayed matching to sample (DMS) assessed temporal lobe functions, while Stockings of Cambridge (SOC) and intra-extra dimensional (IED) shift focused on frontal lobe functions. Patients with postoperative cerebral complications were reported, but excluded from neuropsychological follow-up. In addition to the CANTAB data, pre- and postoperative clinical and radiological data were collected. HRQOL was assessed using Short Form 36 (SF-36) pre- and postoperatively. We found significant improvement in the two temporal tests assessing memory, but no improvement in the two frontal tests assessing executive function. HRQOL was significantly reduced preoperatively in two of eight SF-36 domains and improved significantly in four domains postoperatively. CANTAB facilitates detection of cognitive improvements after decompression of the cyst in patients with AC in the middle fossa. The improvements were detected on the tests sensitive to temporal lobe problems only, not on the tests more sensitive to frontal lobe affection. This establishes construct validity for CANTAB for the first time in this population.

Comparing Tactile Pattern and Vibrotactile Frequency Discrimination: A Human fMRI Study

We investigated to which extent the discrimination of tactile patterns and vibrotactile frequencies share common cortical areas. An adaptation paradigm has been used to identify cortical areas specific for processing particular features of tactile stimuli. Healthy right-handed subjects performed a delayed-match-to-sample (DMTS) task discriminating between pairs of tactile patterns or vibrotactile frequencies in separate functional MRI sessions. The tactile stimuli were presented to the right middle fingertip sequentially with a 5.5 s delay. Regions of interest (ROIs) were defined by cortical areas commonly activated in both tasks and those that showed differential activation between both tasks. Results showed recruitment of many common brain regions along the sensory motor pathway (such as bilateral somatosensory, premotor areas, and anterior insula) in both tasks. Three cortical areas, the right intraparietal sulcus (IPS), supramarginal gyrus (SMG)/parietal operculum (PO), and PO, were significantly more activated during the pattern than in the frequency task. Further BOLD time course analysis was performed in the ROIs. Significant BOLD adaptation was found in bilateral IPS, right anterior insula, and SMG/PO in the pattern task, whereas there was no significant BOLD adaptation found in the frequency task. In addition, the right hemisphere was found to be more dominant in the pattern than in the frequency task, which could be attributed to the differences between spatial (pattern) and temporal (frequency) processing. From the different spatio-temporal characteristics of BOLD activation in the pattern and frequency tasks, we concluded that different neuronal mechanisms are underlying the tactile spatial and temporal processing.

Dynamic modulation of direction selectivity by task demands in prefrontal cortex

Responses of neurons in the prefrontal cortex (PFC) have been shown to represent behaviorally relevant sensory information. Recent work revealed that PFC neurons exhibit direction selective (DS) responses to visual motion used in a delayed match-to-sample (DMTS) task in which the monkeys compared two directions of motion separated by a brief delay (Zaksas & Pasternak, J. Neurosci, 2006). We asked whether this directionality is preserved when the monkeys were asked to ignore stimulus direction. We compared responses of PFC neurons to identical visual motion stimuli presented during three different tasks. In separate blocks of trials the animals discriminated the direction or the speed of motion, or were rewarded for passively maintaining fixation. We found that DS responses were drastically attenuated under both conditions in which stimulus direction was irrelevant and that the nature of this attenuation was task dependent. When the monkey discriminated stimulus speed and ignored its direction, DS activity was strongly attenuated early in the response and emerged about 100ms later than during the direction discrimination task. This early reduction of DS activity resulted not from a decrease in the response to the preferred direction, but from an increase in the response to the anti-preferred direction, suggesting an active release from inhibition characteristic of direction selectivity in visual cortical neurons. In contrast, during the passive fixation task, reduction in DS activity resulted largely from the decrease in the response to the preferred direction, which unlike the more transient loss in DS during the speed task, persisted throughout the response. Our results demonstrate the existence of a dynamic gating mechanism by which PFC neurons can modulate direction selectivity characteristic of visual cortical neurons.

Neural correlates of fast pupil dilation in nonhuman primates: Relation to behavioral performance and cognitive workload

Pupil dilation in humans has been previously shown to correlate with cognitive workload, whereby increased frequency of dilation is associated with increased degree of difficulty of a task. It has been suggested that frontal oculomotor brain areas control cognitively related pupil dilations, but this has not been confirmed due to lack of animal models of cognitive workload and task-related pupil dilation. This is the first report of a wavelet analysis applied to continuous measures of pupil size used to detect the onset of abrupt pupil dilations and the frequency of those dilations in nonhuman primates (NHPs) performing a trial-unique delayed-match-to-sample (DMS) task. A unique finding shows that electrophysiological recordings in the same animals revealed firing of neurons in frontal cortex correlated to different components of pupil dilation during task performance. It is further demonstrated that the frequency of fast pupil dilations (but not rate of eye movements) correlated with cognitive workload during task performance. Such correlations suggest that frontal neuron encoding of pupil dilation provides critical feedback to other brain areas involved in the processing of complex visual information.

The interactive effect of acute ovarian suppression and the cholinergic system on visuospatial working memory in young women

Women have an increased risk of developing Alzheimer's Dementia (AD) compared to men. It has been postulated that this risk may be modulated by a reduction in the neuroprotective effects of estrogen on the brain in the early postmenopausal period. This view is supported by, for example, findings that ovariectomy in younger women (i.e. prior to menopause) significantly increases the risk for the development of memory problems and AD in later life. However, the biological basis underlying these cognitive changes is still poorly understood. Our aim in the current study was to understand the interactive effects of acute, pharmacological-induced menopause (after Gonadotropin Hormone Releasing Hormone agonist (GnRHa) treatment) and scopolamine (a cholinergic antagonist used to model the memory decline associated with aging and AD) on brain functioning. To this end we used fMRI to study encoding during a Delayed Match to Sample (DMTS) (visual working memory) task. We report a relative attenuation in BOLD response brought about by scopolamine in regions that included bilateral prefrontal cortex and the left parahippocampal gyrus. Further, this was greater in women post-GnRHa than in women whose ovaries were functional. Our results also indicate that following pharmacological-induced menopause, cholinergic depletion produces a more significant behavioural deficit in overall memory performance, as manifest by increased response time. These findings suggest that acute loss of ovarian hormones exacerbate the effects of cholinergic depletion on a memory-related, behavioural measure, which is dependent on fronto-temporal brain regions. Overall, our findings point to a neural network by which acute loss of ovarian function may interact to negatively impact encoding.

P02-243 - Neurocognition and temperament in borderline and schizotypal personality disorder

ObjectiveExplore the neurocognitive and temperament profile of borderline personality disorder (BPD) and schizotypal personality disorder (SPD) to better understand their underlying neurobiology for improved treatment.Methods17 BPD, 16 SPD, and 15 healthy controls (HCs) were given a comprehensive neuropsychological battery (CANTAB), the Iowa Gambling Task, a time perception task, and questionnaires of impulsivity, temperament, emotion, and frontal behavior (measures orbitofrontal cortex (OFC) dysfunction).ResultsBPD and SPD patients performed significantly worse on the delayed match to sample (DMS) task compared to HCs, but had preserved function on decision-making, planning, time perception and attention tasks. SPD patients performed significantly worse on spatial working memory (SWM) tasks, and had higher religious commitment scores than HC and BPD groups, which correlated with their SWM deficits. BPD patients had significantly more frontal behaviors and emotions than both groups, which correlated with their emotionality, impulsivity, BPD symptoms, and temperament traits.ConclusionsBoth BPD and SPD groups had a deficit on the DMS task, sensitive to medial temporal lobe (MTL) dysfunction, but only SPD patients had SWM deficits, indicative of dorsolateral frontal cortex (DLFC) dysfunction, which correlated with their high religious commitment in line with their odd beliefs and magical thinking. Only BPD patients had frontal behavior deficits, related to OFC dysfunction, which positively correlated with their emotionality, impulsivity, and temperament traits. While both disorders may have a deficit in MTL function, DLFC dysfunction may contribute to SPD symptoms, and OFC dysfunction to BPD symptoms, suggesting treatment should target unique prefrontal cortex regions respectively.

Evidence from reaction times for an anticipatory process in symbolic delayed matching-to-sample

It was predicted that a delay between sample offset and comparison onset in symbolic delayed matching-to-sample (DMTS) would allow time for the anticipatory retrieval of the correct comparison so that the match/no match status of the presented comparison could be decided more swiftly. The relation between delay and reaction time (RT) was explored in participants after they had been similarly tested, as a control, on identity DMTS using the same stimuli. In most participants there was the predicted inverse relation between delay and RT in symbolic DMTS, but no such relation in identity DMTS. Subsequently an arithmetic test, designed to allow a simple calculation before or after presentation of the comparison, was used to demonstrate an analogous effect of a delay on RT.

The effects of chronic methylphenidate administration on operant test battery performance in juvenile rhesus monkeys

Methylphenidate (MPH) is an amphetamine derivative widely prescribed for the treatment of attention deficit–hyperactivity disorder. Recent concern over its genotoxic potential in children [11] spurred a study on the effects of chronic MPH treatment in a nonhuman primate population and the studies reported here were conducted in conjunction with that study in the same animals. Here, the focus was on the ability of juvenile rhesus monkeys to learn how to perform a battery of operant behavioral tasks while being treated chronically with MPH. Performance of the National Center for Toxicological Research (NCTR) Operant Test Battery (OTB) was used to quantify the learning of tasks thought to model specific aspects of cognitive function including learning, motivation, color and position discrimination, and short-term memory. The OTB tasks designed to assess these specific behaviors included Incremental Repeated Acquisition (IRA), Progressive Ratio (PR), Conditioned Position Responding (CPR), and Delayed Matching-to-Sample (DMTS), respectively. Juvenile males (n=10/group) pressed levers and press-plates for banana-flavored food pellets. Subjects were treated orally, twice a day, five days per week (M–F) for 66 weeks with escalating doses (0.15 mg/kg initially, increased to 2.5 mg/kg for the low dose group and to 12.5 mg/kg for the high dose group) and tested in OTB tasks 30 to 60 min after the morning dose. The findings indicate that MPH at doses up to 2.5 mg/kg twice per day were well tolerated (performance was no different than controls) but at doses of 12.5 mg/kg twice per day there was a significant decrement in OTB performance, characterized by decreases in both percent task completed and response rates for all tasks. These effects of MPH seem primarily due to decreases in motivation to perform for food, which is not surprising given the well known appetite suppressing effects of amphetamine-like stimulants. Thus, the current data do not strongly suggest cognitive impairments following chronic MPH administration.

Computational modeling and empirical studies of hippocampal neurogenesis-dependent memory: Effects of interference, stress and depression

Prolonged stress causes dysregulation in the hypothalamic-pituitary-adrenal axis and may contribute to the pathogenesis of major depressive disorder (MDD). MDD is associated with pathological changes in several brain regions, particularly the prefrontal cortex and hippocampus. Evidence from animal research suggests that one of the earliest signs of pathological change after exposure to stress is a reduction in hippocampal neurogenesis. We therefore sought to test the prediction that people in the earliest stages of a first episode of depression would show selective memory deficits on neurogenesis-dependent tasks. Our computational model predicts that new neurons are important for representing distinct contexts; thus, when overlapping memories are learned over an interval of several days, during which time some neuronal turnover has taken place, the neurogenesis should reduce the potential for interference between the overlapping memories. At much shorter time scales, within the span of a single memory episode, rather than contributing to pattern separation, neurogenesis might play more of an integrative role in mediating contextual associative learning. Consistent with this, empirical evidence from animal studies suggests a role for the new neurons in forming complex event memories that bridge across time delays. This leads us to predict selective memory deficits on putative neurogenesis-dependent tasks in the earliest pre-clinical stages of a first episode of depression, before a clinical diagnosis has been made and prior to the development of more serious pathological brain changes. We present the results of new simulations with the model, lending further support to the prediction that neurogenesis reduces interference when memory events are separated by several days. We also report findings from an empirical study in which we tested a large number of undergraduates on a set of cognitive and memory tests from the CANTAB battery, and also administered neuropsychological inventories for stress, depression and anxiety. One of the subtests in the CANTAB battery, the delayed match to sample (DMS) task, was of particular interest as delayed non-match to sample has been found in animal studies to be dependent upon neurogenesis. Our empirical results indicate that as predicted, participants scoring high on the Beck Depression Inventory show a selective deficit on the DMS at long delays while performing on par with non-depressed participants on all other tasks. The potential to detect very early signs of major depression using simple neurogenesis-dependent cognitive tests could have important implications for the diagnosis and treatment of this debilitating and highly prevalent disorder.

Basal ganglia and memory retrieval during delayed match-to-sample and non-match-to-sample tasks

Top-down guidance of visual search requires the ability tobias the processing of visual features towards the charac-teristics of the desired object. Whatever form they maytake, these characteristics (that we will call here a templateof the object) have to be transferred from memory to thevisual cortical areas, either from long-term memory orworking memory. High visual areas like the inferotempo-ral cortex, or visuo-mnemonic areas in the medial tempo-ral lobe have been shown to exhibit sustained activitiesduring delayed matching-to-sample (DMS) or delayednon-matching-to-sample (DNMS) tasks, showing theirinvolvement in working memory (WM) processes [1].Particularly, perirhinal cortex (PRh) is involved in objectrecognition, novelty detection and categorization, and itsimpairment leads to severe deficits in DMS and DNMStasks [2].We designed in [3] a computational model of PRh thatwas able to perform multimodal categorization despitepartial object presentation. Its main feature was the incor-poration of dopaminergic modulation of synaptic cur-rents, which allowed the model to exhibit sustainedactivities in clusters of cells representing a given objectunder an optimal level of tonic dopamine (DA) firing. Wealso observed propagation of activity within a cluster,which leads to the interesting property that the visualinformation contained in a cluster can be retrieved troughthe stimulation of a very limited number of cells by tha-lamic afferents. We therefore formulated the hypothesisthat PRh is potential site where visual memory can beretrieved through partial thalamic stimulation in order tobias processing in the ventral stream through feedbackmodulation.Given the fact that PRh receives connections from parts ofthe thalamus that are tonically inhibited by basal ganglia(BG) structures [4], we here suggest that BG can act as con-troller for memory retrieval in PRh, but without any visualdetails about the object to be retrieved. We tested thishypothesis by building a computational model involvingPRh, BG structures, thalamus and a prefrontal cortex(PFC) area that performs static working memory in amanner functionally similar to [5]. We applied this modelto interlaced DMS and DNMS tasks, where one of twoobjects (A or B) is first presented to the system, followedby a task cue indicating whether the system should per-form DMS or DNMS, then both A and B objects. If the sys-tem selects the correct object in PRh, it receives aprobabilistic reward that elicits a phasic DA burst.The model is composed of competing mean firing-rateneurons that interacts through connections havingweights evolve through an homeostatic Hebbian learningrule. Both PRh and PFC areas project on the input struc-ture of BG, the nucleus accumbens (NAcc), which in turnproject to the globus pallidus (GPi) that tonically inhibitsthe thalamus. Selective inhibition of a GPi cell allows itsefferent thalamic cells to exhibit activity and thereforestimulate the corresponding cluster in PRh. The DA cellsslowly learn to predict reward associated to NAcc patterns

Metamemory in tufted capuchin monkeys (Cebus apella)

Whereas evidence for metacognition by nonhuman primates has been obtained in great apes and old world monkeys, it is weaker in new world monkeys. For instance, capuchin monkeys may fail to recognize their own knowledge of the location of invisible bait. In the present study, we tested whether tufted capuchin monkeys would flexibly change their behavior in a delayed matching-to-sample (DMTS) test depending upon the strength of their memory trace of the sample. In Experiment 1, two monkeys were tested on a modified 9-alternative DMTS task with various delays on a computerized display. In some trials, the monkeys could choose whether to go for a memory test or for a simple key touch as an escape from the test. In other trials, they were forced to go for the memory test. Both monkeys escaped from the memory test more often when their matching accuracy on forced tests was lower. In one of the monkeys, the matching accuracies on chosen memory tests decreased more slowly as a function of delay length, and were higher after long delays than those on forced memory tests. This suggests that at least one capuchin monkey was able to recognize the strength of his own memory trace. Experiment 2 employed occasional no-sample tests, in which the monkeys faced the task choice without presentation of any sample for the trial. The monkey who was successful in Experiment 1 declined the memory test more often in no-sample trials than regular trials, further indicating metamemory in this individual. In Experiment 3, this successful monkey received a task, in which he was sometimes able to choose between shape MTS or texture MTS tasks. However, his matching accuracies did not differ between chosen tasks and forced tasks. Thus, the metamemory possessed by this new world monkey species may be more like a flag, showing strength of memory trace, than an elaborate representation showing details of the memory trace.

How well does structural equation modeling reveal abnormal brain anatomical connections? An fMRI simulation study

Many brain disorders result from alterations in the strength of anatomical connectivity between different brain regions. This study investigates whether such alterations can be revealed by examining differences in interregional effective connectivity between patient and normal subjects. We applied one prominent effective connectivity method – Structural Equation Modeling (SEM) – to simulated functional MRI (fMRI) timeseries from a neurobiologically realistic network model in which the anatomical connectivity is known and can be manipulated. These timeseries were simulated for two task conditions, a delayed match-to-sample (DMS) task and passive-viewing, and for “normal subjects” and “patients” who had one weakened anatomical connection in the neural network model. SEM results were compared between task conditions as well as between groups. A significantly reduced effective connectivity corresponding to the weakened anatomical connection during the DMS task was found. We also obtained a significantly reduced set of effective connections in the patient networks for anatomical connections “downstream” from the weakened linkage. However, some “upstream” effective connections were significantly larger in the patient group relative to normals. Finally, we found that of the SEM model measures we examined, the total error variance was the best at distinguishing a patient network from a normal network. These results suggest that caution is necessary in applying effective connectivity methods to fMRI data obtained from non-normal populations, and emphasize that functional interactions among network elements can appear as abnormal even if only part of a network is damaged.

Memory for “what”, “where”, and “when” information in rhesus monkeys (Macaca mulatta).

The present study examined working memory for what, where, and when information in rhesus monkeys (Macaca mulatta) using a computerized task. In Experiment 1, monkeys completed three delayed matching-to-sample (DMTS) tasks: (1) identity DMTS, (2) spatial DMTS, and (3) temporal DMTS. In Experiment 2, the identity and spatial tasks were combined so that monkeys had to report both what and where information about an event. In Experiment 3, the identity, spatial, and temporal tasks were combined to examine what-where-when memory integration. The rhesus monkeys reported all three components of the events, and there was some evidence suggesting that these components were integrated in working memory.

Visual working memory and delay activity in highly selective neurons in the inferior temporal cortex

Visual working memory and delay activity in highly selective neurons in the inferior temporal cortex

A computational model of basal ganglia involved in the cognitive control of visual perception

Event Abstract Back to Event A computational model of basal ganglia involved in the cognitive control of visual perception Fred H. Hamker1* and Julien Vitay2 1 Technichal University Chemnitz, Computer Science Department, Germany 2 Westfalischen Wilhelms Universitat, Psychologisches Institut II, Germany Goal-directed visual perception requires to maintain and manipulate a template of the desired target in visual working memory (WM) that allows to bias processing in the posterior lobe. It is still unclear how such goal-directed perception is implemented in the brain. We propose that such interaction between visual WM and attentional processing involves a network of brain areas consisting of inferotemporal cortex (IT) for the retrieval of visual information associated to the target, dorsolateral-prefrontal cortex (dlPFC) for the manipulation and maintenance of the target template in face of distractors, medial temporal lobe (MTL) regions for rapid encoding and novelty detection, as well as basal ganglia (BG) for the switching and activation of WM representations in dlPFC.We designed a novel computational model of BG, while it interacts with a model of perirhinal cortex (PRh, part of the medial temporal lobe) and a simple model of dlPFC for memorizing objects, to explore how the BG might be involved in the cognitive control of visual perception. The BG model is composed of the striatum receiving connections from PRh and dlPFC. The striatum inhibits SNr which in turn tonically inhibits a thalamic nucleus interacting with PRh. Homeostatic Hebbian learning takes place simultaneously in the connections from cortical areas to the striatum (representing the context of of the task) and in the connections from striatum to SNr as well as within SNr (learning to retrieve the correct representation). Moreover, a dopaminergic cell learns to compute the difference between the reward actually received and the expectation of reward based on striatal representations and modulates learning in the other areas.We applied this model to simultaneously learn delayed matching-to-sample (DMS) and delayed nonmatching-to-sample (DNMS) tasks. Whether DMS or DNMS should be performed is defined by a contextual information presented after the sample and before the search array composed of two targets. Reward is given to the system when it selects the correct target through thalamic stimulation of PRh. The model has to represent efficiently the context in the striatum to solve the tasks and is able to learn them concurrently after 400 trials, independently of the number of cells in SNr, what denotes a parallel search of the correct representation. If at the beginning of learning, several cells in SNr can become selective for the same striatal pattern, the learned competition between them progressively selects the only one that disinhibits the correct target. The reward-predictive value of striatal representations also takes into account the probability of reward associated to an object.Similarly to the PVLV model of O'Reilly and Frank, our model reproduces the reward-related firing pattern of dopaminergic cells in conditioning. However, our model highlights the role of BG processing in visual WM processes, not only in its cognitive component but also in the retrieval of target information. It explains how vision can be guided by the goals of the task at hand. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Decision, control and reward Citation: Hamker FH and Vitay J (2009). A computational model of basal ganglia involved in the cognitive control of visual perception. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.006 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Aug 2009; Published Online: 25 Aug 2009. * Correspondence: Fred H Hamker, Technichal University Chemnitz, Computer Science Department, Chemnitz, Germany, fred.hamker@informatik.tu-chemnitz.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Fred H Hamker Julien Vitay Google Fred H Hamker Julien Vitay Google Scholar Fred H Hamker Julien Vitay PubMed Fred H Hamker Julien Vitay Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Estrogen and working memory for emotional facial expressions

Event Abstract Back to Event Estrogen and working memory for emotional facial expressions Antonella Gasbarri1*, Assunta Pompili1, Armida D-Onofrio1, Benedetto Arnone1, Debora Falconieri1, Clotilde M. Tavares2 and Carlos Tomaz2 1 University of L'Aquila, Department of Biomedical Science & Technology, Italy 2 University of Brasília, Department of physiological Science, Brazil The influence of estrogen on nervous system extends beyond its role in the control of the reproductive function; in addition, the hormonal influence on cognitive functions, such as learning and memory, was also reported. Across the menstrual cycle, the performance in memory tasks can oscillate, according to the hormonal levels. Therefore, in this study we evaluated in young women, during the different phases of their menstrual cycle, the performance in a Delayed Matching-to-Sample (DMTS) working memory task for emotional facial expressions. Our results indicate that high levels of estrogen in the follicular phase could have a negative effect on DMTS with emotional stimuli. Moreover, compared to the menstrual phase, in the follicular phase the percent of errors was significantly higher for sadness and disgust facial expressions. The evaluation of the times of answer for each emotional facial expression revealed a significant difference between follicular and luteal phases, relatively to sadness. Moreover, high levels of estrogen in the follicular phase can impair the performance of working memory for selective facial expressions suggesting that, during the menstrual phases at high conception risk, women give less importance to emotional expressions with negligible reproductive significance, such as sadness and disgust. Our data show that fluctuations of estrogens across the menstrual cycle affect several behaviors and could contribute to identify therapies for the treatment of disorders related to menstrual cycle phases and menopause in women. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Poster Presentation Topic: Poster presentations Citation: Gasbarri A, Pompili A, D-Onofrio A, Arnone B, Falconieri D, Tavares CM and Tomaz C (2009). Estrogen and working memory for emotional facial expressions. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.157 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Jun 2009; Published Online: 09 Jun 2009. * Correspondence: Antonella Gasbarri, University of L'Aquila, Department of Biomedical Science & Technology, L'Aquila, Italy, antonella.gasbarri@cc.univaq.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Antonella Gasbarri Assunta Pompili Armida D-Onofrio Benedetto Arnone Debora Falconieri Clotilde M Tavares Carlos Tomaz Google Antonella Gasbarri Assunta Pompili Armida D-Onofrio Benedetto Arnone Debora Falconieri Clotilde M Tavares Carlos Tomaz Google Scholar Antonella Gasbarri Assunta Pompili Armida D-Onofrio Benedetto Arnone Debora Falconieri Clotilde M Tavares Carlos Tomaz PubMed Antonella Gasbarri Assunta Pompili Armida D-Onofrio Benedetto Arnone Debora Falconieri Clotilde M Tavares Carlos Tomaz Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Mechanisms underlying cognitive enhancement and reversal of cognitive deficits in nonhuman primates by the ampakine CX717

Performance of cognitive tasks in nonhuman primates (NHPs) requires specific brain regions to make decisions under different degrees of difficulty or "cognitive load." Local cerebral metabolic activity ([18F]FDG PET imaging) in dorsolateral prefrontal cortex (DLPFC), medial temporal lobe (MTL), and dorsal striatum (DStr) is examined in NHPs performing a delayed-match-to-sample (DMS) task with variable degrees of cognitive load. Correlations between cognitive load and degree of brain metabolic activity were obtained with respect to the influence of the ampakine CX717 (Cortex Pharmaceuticals), using brain imaging and recordings of neuronal activity in NHPs and measures of intracellular calcium release in rat hippocampal slices. Activation of DLPFC, MTL, and DStr reflected changes in performance related to cognitive load within the DMS task and were engaged primarily on high load trials. Similar increased activation patterns and improved performance were also observed following administration of CX717. Sleep deprivation in NHPs produced impaired performance and reductions in brain activation which was reversed by CX717. One potential basis for this facilitation of cognition by CX717 was increased firing of task-specific hippocampal cells. Synaptic mechanisms affected by CX717 were examined in rat hippocampal slices which showed that N-methyl-D-aspartic acid-mediated release of intracellular calcium was reduced in slices from sleep-deprived rats and reversed by application of CX717 to the bathing medium. The findings provide insight into how cognition is enhanced by CX717 in terms of brain, and underlying neural, processes that are activated on high vs. low cognitive load trials.

Protracted cognitive effects produced by clonidine in Macaca nemestrina performing a delayed matching task

The alpha(2)-adrenergic receptor agonist clonidine was examined for its ability to improve working memory in monkeys. Clonidine (0.116-34.8 microg/kg) was administered to six pigtail macaques in their performance of a computer-assisted delayed matching-to-sample (DMTS) task. During DMTS sessions initiated 1 hour after dosing, there was a slight improvement in mean task accuracy (long delay trials; 0.116-microg/kg). On the following day, there was continued and added improvement in accuracies associated with the long delay trials. On the day following 1.16-microg/kg, the entire memory retention curve was shifted to the right of vehicle. When the animals were again tested 48 hours after dosing (no pretreatment), these two patterns of task enhancement were continued and enhanced. Mean task accuracy associated with long delay trials was significantly increased by 14.2% trials correct when animals were originally treated with 0.116-microg/kg of clonidine. Mean task accuracy associated with medium delay trials was significantly increased by 11.8% trials correct when animals were treated with 1.16-microg/kg. On the sixth day after clonidine, task accuracies were still significantly improved during medium delay trials after 0.116-microg/kg. Median sample and choice latencies were not significantly influenced by clonidine treatment. These findings are consistent with the ability of clonidine to induce a protracted improvement in aspects of working memory. Early (attentional) and late (retention) components of memory appeared to be differentially sensitive to the dose of clonidine. Central alpha(2)-adrenergic receptors should be considered legitimate drug targets for future compound development for cognition enhancement.

Simulated neural dynamics of decision-making in an auditory delayed match-to-sample task

An important goal of research on the cognitive neuroscience of decision-making is to produce a comprehensive model of behavior that flows from perception to action with all of the intermediate steps defined. To understand the mechanisms of perceptual decision-making for an auditory discrimination experiment, we connected a large-scale, neurobiologically realistic auditory pattern recognition model to a three-layer decision-making model and simulated an auditory delayed match-to-sample (DMS) task. In each trial of our simulated DMS task, pairs of stimuli were compared each stimulus being a sequence of three frequency-modulated tonal-contour segments, and a "match" or "nonmatch" button was pressed. The model's simulated response times and the different patterns of neural responses (transient, sustained, increasing) are consistent with experimental data and the simulated neurophysiological activity provides insights into the neural interactions from perception to action in the auditory DMS task.

Shape Selectivity in Primate Frontal Eye Field

Previous neurophysiological studies of the frontal eye field (FEF) in monkeys have focused on its role in saccade target selection and gaze shift control. It has been argued that FEF neurons indicate the locations of behaviorally significant visual stimuli and are not inherently sensitive to specific features of the visual stimuli per se. Here, for the first time, we directly examined single cell responses to simple, two-dimensional shapes and found that shape selectivity exists in a substantial number of FEF cells during a passive fixation task or during the sample, delay (memory), and eye movement periods in a delayed match to sample (DMTS) task. Our data demonstrate that FEF neurons show sensory and mnemonic selectivity for stimulus shape features whether or not they are behaviorally significant for the task at hand. We also investigated the extent and localization of activation in the FEF using a variety of shape stimuli defined by static or dynamic cues employing functional magentic resonance imaging (fMRI) in anesthetized and paralyzed monkeys. Our fMRI results support the electrophysiological findings by showing significant FEF activation for a variety of shape stimuli and cues in the absence of attentional and motor processing. This shape selectivity in FEF is comparable to previous reports in the ventral pathway, inviting a reconsideration of the functional organization of the visual system.