Optogenetic silencing of the Anterior Cingulate Cortex impairs working memory in a delayed non-match to trajectory task
Working memory is a fundamental cognitive ability, allowing us to keep information in memory for the time needed to perform a given task. A complex neural circuit fulfills these functions, among which is the anterior cingulate cortex (CG). Functionally and anatomically connected to the medial prefrontal, retrosplenial, midcingulate and hippocampus, as well as motor cortices, CG has been implicated in retrieving appropriate information when needed to select and control appropriate behavior. The role of cingulate cortex in working memory-guided behaviors remains unclear due to the lack of studies reversibly interfering with its activity during specific epochs of working memory. We used light to activate eNpHR3.0 and thus silence cingulate neurons while animals perform a standard delayed non-match to trajectory task. We found that, while not causing an impairment in eNpHR3.0+ animals when compared to eNpHR3.0-CTRL animals, silencing cingulate neurons during retrieval decreases the mean performance if compared to silencing during encoding. Such retrieval-associated changes are accompanied by longer delays in control animals, consistent with an adaptive recruitment of additional cognitive resources.