Examined attentional (ATT) mechanisms needed to select relevant objects for visual processing and control over behavior in 3 macaque monkeys. During fixation, a cue was presented at the center of gaze, followed by a blank delay period. After the delay, choice stimuli were presented extrafoveally, and detection of a stimulus matching the cue was rewarded. The behavioral response was a saccadic eye movement to the target in 1 version of the task and a lever release in another. The array was composed of one "good" stimulus (effective in driving the cell when presented alone) and 1 or more "poor", or ineffective, stimuli. Most cells showed higher delay activity after a good stimulus. Baseline cell activity was also higher preceding a good cue, if the animal expected it to occur. When the choice array was presented, most cells showed suppressed stimulus interactions as well as strong ATT effects. When the choice array was presented in the contralateral visual field, most cells initially responded the same, regardless of the target. Results support a "biased competition" model of ATT: objects in the visual field compete for cortical representation, with competition biased in favor of behaviorally relevant objects by virtue of feedback from structures involved in working memory. ((c) 1999 APA/PsycINFO, all rights reserved)
Responses of neurons in inferior temporal cortex during memory-guided visual search
Chelazzi L.;
1998-01-01
Abstract
Examined attentional (ATT) mechanisms needed to select relevant objects for visual processing and control over behavior in 3 macaque monkeys. During fixation, a cue was presented at the center of gaze, followed by a blank delay period. After the delay, choice stimuli were presented extrafoveally, and detection of a stimulus matching the cue was rewarded. The behavioral response was a saccadic eye movement to the target in 1 version of the task and a lever release in another. The array was composed of one "good" stimulus (effective in driving the cell when presented alone) and 1 or more "poor", or ineffective, stimuli. Most cells showed higher delay activity after a good stimulus. Baseline cell activity was also higher preceding a good cue, if the animal expected it to occur. When the choice array was presented, most cells showed suppressed stimulus interactions as well as strong ATT effects. When the choice array was presented in the contralateral visual field, most cells initially responded the same, regardless of the target. Results support a "biased competition" model of ATT: objects in the visual field compete for cortical representation, with competition biased in favor of behaviorally relevant objects by virtue of feedback from structures involved in working memory. ((c) 1999 APA/PsycINFO, all rights reserved)
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
