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Task difficulty: ignoring, attending to, and discriminating a visual stimulus yield progressively more activity in inferior temporal neurons

Task difficulty: ignoring, attending to, and discriminating a visual stimulus yield progressively... 221 83 83 2 2 H. Spitzer B. J. Richmond Laboratory of Neuropsychology, National Institute of Mental Health Bldg. 9, Rm. 1N107 20892 Bethesda MD USA Department of Biomedical Engineering Technion-Israel Institute of Technology 3200 Haifa Israel Summary To study the influence of task difficulty on the stimulus-elicited responses of inferior temporal (IT) neurons, the stimulus-elicited responses of 64 neurons were recorded from IT cortex of three rhesus monkeys while they performed three behavioral tasks — an irrelevant-stimulus task, a stimulus detection task, and a stimulus discrimination task. The monkey could ignore the stimulus entirely in the irrelevant-stimulus task, was required only to detect stimulus dimming in the stimulus detection task, and was required to attend to specific properties of the stimulus in the discrimination task. The excitatory responses in the discrimination and stimulus detection tasks were larger than those in the irrelevantstimulus task (61% and 33%, respectively, of the individual differences were significant), and excitatory responses in the discrimination task were larger than those in the detection task (49% of the individual differences reached significance). Twenty percent of the stimulus presentations elicited inhibitory responses that were followed by off-responses. The off-responses were modulated by the tasks in the same order as the excitatory on-responses. Assuming that the off-response strengths indicate the depth of the stimulus-induced inhibition, these results suggest that inhibitory responses were influenced across these tasks in a manner similar to the excitatory responses. When the neuronal responses were related to the difficulties of these tasks, both the response strength and errors were seen to be least during the irrelevant-stimulus task and greatest during the discrimination task. This relationship suggests that the visual responsiveness of IT neurons is related to the degree of attention the animal pays to the stimulus. Based on this and findings from several related studies, a more refined hypothesis can be formulated, namely, visual responsiveness of IT neurons is related to the degree of attention the animal pays to stimulus pattern, specifically. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experimental Brain Research Springer Journals

Task difficulty: ignoring, attending to, and discriminating a visual stimulus yield progressively more activity in inferior temporal neurons

Spitzer, H.; Richmond, B.
Experimental Brain Research , Volume 83 (2) – Jan 1, 1991
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References (24)

Publisher
Springer Journals
Copyright
Copyright © 1991 by Springer-Verlag
Subject
Biomedicine; Neurosciences; Neurology
ISSN
0014-4819
eISSN
1432-1106
DOI
10.1007/BF00231157
Publisher site
See Article on Publisher Site

Abstract

221 83 83 2 2 H. Spitzer B. J. Richmond Laboratory of Neuropsychology, National Institute of Mental Health Bldg. 9, Rm. 1N107 20892 Bethesda MD USA Department of Biomedical Engineering Technion-Israel Institute of Technology 3200 Haifa Israel Summary To study the influence of task difficulty on the stimulus-elicited responses of inferior temporal (IT) neurons, the stimulus-elicited responses of 64 neurons were recorded from IT cortex of three rhesus monkeys while they performed three behavioral tasks — an irrelevant-stimulus task, a stimulus detection task, and a stimulus discrimination task. The monkey could ignore the stimulus entirely in the irrelevant-stimulus task, was required only to detect stimulus dimming in the stimulus detection task, and was required to attend to specific properties of the stimulus in the discrimination task. The excitatory responses in the discrimination and stimulus detection tasks were larger than those in the irrelevantstimulus task (61% and 33%, respectively, of the individual differences were significant), and excitatory responses in the discrimination task were larger than those in the detection task (49% of the individual differences reached significance). Twenty percent of the stimulus presentations elicited inhibitory responses that were followed by off-responses. The off-responses were modulated by the tasks in the same order as the excitatory on-responses. Assuming that the off-response strengths indicate the depth of the stimulus-induced inhibition, these results suggest that inhibitory responses were influenced across these tasks in a manner similar to the excitatory responses. When the neuronal responses were related to the difficulties of these tasks, both the response strength and errors were seen to be least during the irrelevant-stimulus task and greatest during the discrimination task. This relationship suggests that the visual responsiveness of IT neurons is related to the degree of attention the animal pays to the stimulus. Based on this and findings from several related studies, a more refined hypothesis can be formulated, namely, visual responsiveness of IT neurons is related to the degree of attention the animal pays to stimulus pattern, specifically.

Journal

Experimental Brain Research – Springer Journals

Published: Jan 1, 1991

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