HOW TASK-RELATED ARE THE RESPONSES OF INFERIOR TEMPORAL NEURONS

The responses of inferior temporal (IT) neurons may depend on the beha vioral context of the stimuli; e.g. in Konorski tasks responses to two successively presented physically identical stimuli can be markedly d ifferent. This effect has been interpreted as being linked to the beha vioral task, and to be involved in short-term memory and/or the tempor al comparison of successively presented stimuli. We tested whether thi s behavioral context effect also occurs when the monkey is not executi ng a Konorski task, i.e. no temporal comparison of stimuli is being pe rformed. Responses of the same IT neurons under two behavioral conditi ons were compared using the same temporal stimulus sequence (but diffe rent stimuli): a Konorski task and a Fixation task. We found that the occurrence of the behavioral context effect did not depend on the exec ution of the short-term memory task. The observed decline in the level of responses to repeated presentation of similar stimuli is interpret ed as being a passive mechanism involved in recency detection, which o ccurs even if the recency information is not useful for the task. The importance of these results in the interpretation of ''task-related'' neuronal responses is discussed.