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Response Task (response + task)

Distribution by Scientific Domains

Psychology	57%
Medical Sciences	28%

Selected Abstracts

Post-training reversible inactivation of hippocampus reveals interference between memory systems

HIPPOCAMPUS, Issue 2 2002
Jason P. Schroeder
Abstract A post-training reversible lesion technique was used to examine the effects of neural inactivation of the dorsal hippocampus on place and response learning. Male Long-Evans rats trained in one of two versions of a water plus-maze task received post-training intra-hippocampal infusions of the local anesthetic drug bupivacaine (0.75% solution, 0.5 ,l), or saline. Post-training intra-hippocampal infusions of bupivacaine attenuated acquisition of the place task and enhanced acquisition of the response task. Delayed (2-h) post-training infusions of bupivacaine did not affect retention in either task. The findings demonstrate (1) enhanced learning after reversible hippocampal lesions that is independent of treatment influences on non-mnemonic factors, and (2) inactivation of the dorsal hippocampus during the post-training memory consolidation period is sufficient to enhance response learning. Hippocampus 2002;12:280,284. © 2002 Wiley-Liss, Inc. [source]

Prepulse inhibition of the acoustic startle reflex and oculomotor control

PSYCHOPHYSIOLOGY, Issue 4 2005
Ulrich Ettinger
Abstract Prepulse inhibition and the suppression of reflexive saccades on the antisaccade task are thought to tap inhibitory function. Reports of a lack of association between these measures suggest that they reflect different facets of inhibition. This study aimed to reexamine this relationship in a large sample and investigate the association of prepulse inhibition with oculomotor tasks that require inhibition of a reflexive saccade with lower concurrent processing demands than antisaccades, namely the oculomotor delayed response and fixation with distractors tasks. One hundred and seven healthy volunteers took part. Prepulse inhibition was uncorrelated with oculomotor performance. The error rate was highest for antisaccades, intermediate for the delayed response task, and lowest for fixation with distractors, and was correlated across tasks. These findings provide no evidence of a relationship between prepulse inhibition and oculomotor inhibition. Failure in suppressing reflexive saccades toward a peripheral target may represent a common inhibitory component underlying these oculomotor tasks. [source]

Ocular motor delayed-response task performance among patients with schizophrenia and their biological relatives

PSYCHOPHYSIOLOGY, Issue 1 2001
Jennifer E. McDowell
Schizophrenia patients and their relatives have saccadic abnormalities characterized by problems inhibiting a response. The dorsolateral prefrontal cortex and its associated circuitry ostensibly mediate inhibition and support correct delayed response performance. In this context, two components of delayed response task performance are of interest: memory saccade metrics and error saccades made during the delay. To evaluate these variables, an ocular motor delayed response task was presented to 23 schizophrenia patients, 25 of their first-degree biological relatives, and 19 normal subjects. The measure that best differentiated groups was an increased frequency of error saccades generated during the delay by schizophrenia subjects and relatives. Decreased memory saccade gain also characterized patients and relatives. The similar pattern of results demonstrated by the patients with schizophrenia and their relatives suggests that performance on ocular motor delayed response tasks, either alone or in combination with other saccadic variables, may provide useful information about neural substrates associated with a liability for developing schizophrenia. [source]

Low- and high-level controlled processing in executive motor control tasks in 5,6-year-old children at risk of ADHD

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 7 2003
Ariane C. Kalff
Background: The scant research on the characteristics of Attention-Deficit/Hyperactivity Disorder (ADHD) in kindergarten years curtails progress on early assessment of ADHD. Method: By screening a general population sample of 1317 five- to six-year-old children, four groups of children were selected. The performance of 30 children later diagnosed with ADHD was compared with 74 children later diagnosed with ,borderline ADHD' (children exhibiting all ADHD symptoms but without disruptions on two situations), 113 children later diagnosed with other psychopathology, and 126 healthy controls on computerised motor control tasks involving low- and high-level controlled processing. In addition, motor control was compared with movement speed. Results: The children at risk of ADHD were in general less accurate and more variable in their movements than the children with other psychopathology and healthy controls. Under conditions of high-level controlled processing, the children at risk of ADHD were disproportionately more inaccurate and had a more unstable performance with their preferred hand than the other children. In addition, linear effects were found, with the children at risk of ADHD having the worst performance, followed by the children with ,borderline ADHD', and then both groups of control children. No significant group differences were found in movement speed. Conclusions: The main findings are interpreted as evidence for a specific deficit in high-level controlled processing in young children at risk of ADHD, now found in a motor task, rather than a response task. Furthermore, the results support the notion that ADHD represents a dimensional trait. In addition, problems in movement control (the need to allocate attentional capacity) rather than problems in movement speed distinguish children at risk of ADHD from other children. The findings are interpreted as evidence that higher-order executive processes, such as self-control and self-regulation, are already affected early in the development of ADHD. [source]

Differential working memory impairment in bipolar disorder and schizophrenia: effects of lifetime history of psychosis

BIPOLAR DISORDERS, Issue 2 2006
David C Glahn
Background:, Although bipolar disorder and schizophrenia have long been viewed as distinct illnesses, there is growing evidence that these two complex diseases share some common genes, which may manifest as overlapping neuropsychological impairments. Although working memory dysfunction has been proposed to be central to the pathophysiology of schizophrenia, it has received less attention in studies of bipolar disorder. Method:, We applied measures of working memory to patients with schizophrenia (n = 15), patients with schizoaffective disorder (n = 15), patients with psychotic (n = 11) and non-psychotic (n = 15) bipolar disorder, and demographically matched healthy subjects (n = 32), in order to determine the extent to which these groups show common or unique impairments. Results:, While patients with bipolar disorder (with and without psychotic features) and those with schizophrenia/schizoaffective disorder were impaired on backward digit span, only patients with a lifetime history of psychotic features, regardless of diagnosis, were impaired on spatial delayed response task. Conclusions:, Backward digit span performance is comparable in bipolar disorder and schizophrenia, and may be an appropriate endophenotypic marker that cuts across diagnostic categories. In contrast, spatial working memory performance clearly distinguishes non-psychotic bipolar disorder patients from patients with functional psychosis. [source]

Symmetry reversal in schizophrenia

PSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 4 2003
Roland Kalb
Abstract Schizophrenia is associated with cortical asymmetries concentrated in the left fronto-temporal hemisphere. In order to look for functional asymmetries between the two hemispheres, the stimulus,response times of patients were split into smaller periods and the interhemispheric and intrahemispheric correlations between these periods were investigated. Three groups were compared to each other: 22 patients with schizophrenia (Diagnostic and Statistical Manual of Mental Disorders, 4th edn; DSM-IV) treated with neuroleptics; 24 psychiatric neuroleptic-treated patients without schizophrenia; and 30 healthy subjects. All subjects were investigated by simple (one stimulus,one response) and complex (two stimuli,two responses), auditory and visual, right-hemispheric and left-hemispheric stimulus,response tasks. There were no intrahemispheric but significant interhemispheric correlations between the two auditory and between the two visual time fragments in both the healthy and the neuroleptic control group. In contrast there was a significant intrahemispheric correlation between the auditory and visual time fragment in the left hemisphere of patients with schizophrenia and no interhemispheric correlation between the auditory times. The reduction of the interhemispheric auditory correlation is interpreted as an auditory disintegration, the appearance of the left-hemispheric audiovisual correlation as an audiovisual ,hyperintegration' in patients with schizophrenia. It is questionnable as to whether these findings are due to schizophrenia or to the neuroleptic treatment. [source]