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Benjamin Hayden, Heather Dean, Michael Platt; Microstimulation in macaque posterior cingulate cortex biases target choice. Journal of Vision 2006;6(6):742. doi: https://doi.org/10.1167/6.6.742.
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© ARVO (1962-2015); The Authors (2016-present)
The mechanisms by which the brain integrates knowledge about potential rewards with visualspatial information to guide saccades are poorly understood. Recent data from our lab suggest that posterior cingulate cortex (CGp) mediates this process. We have shown that neurons in posterior cingulate cortex (CGp) signal both the expected value of orienting to visual targets and the motivational consequences of orienting to those targets (McCoy et al. 2003). If CGp is the site of binding for rewards and visuospatial information, then microstimulation during the delay period in a free choice task should bias monkeys to choose the contralateral target. To test these hypotheses, we recorded choices made by monkeys when they were allowed to saccade to either of two spatial positions. (The two options were associated with equal rewards.) We stimuluated at sites in CGp on half the trials. We found that microstimulation during the delay period biases choices towards the contralateral target. Stimulation during the delay period also decreases saccade latency. These effects may represent a combination of stimulation-induced bias and a compensatory bias on trials with no stimulation. These results suggest that artificial activation of CGp neurons enhances the motivational salience of contralateral space, and that CGp participates in assigning value to spatial locations.
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