THE EFFECTS OF WORKING MEMORY TRAINING ON THE FUNCTIONAL SPECIALIZATION OF THE PREFRONTAL CORTEX

The dorsolateral prefrontal cortex (PFC) has long been associated with the performance of working memory tasks; however the functional specialization of this area has been debated. Several studies have identified differences in stimulus property selectivity along the dorsal-ventral axis. Additionally, a proposed anterior-posterior axis of selectivity where anterior regions are more selective to task rules and posterior areas are more selective to stimulus properties has been proposed in recent years. To test the presence and properties of these axes, we recorded neural activity from monkeys prior to training. Our results showed a clear shift in stimulus property selectivity moving posterior-to-anterior. Posterior PFC regions were more selective to the stimulus properties than anterior PFC regions were. Additionally, we observed no difference between the posterior regions when testing their selectivity to stimuli features, but the posterior-dorsal region was much more selective to stimulus location than any other region. While ventral regions were more selective to stimulus features than dorsal regions, there was a posterior-anterior gradient of selectivity for stimulus location. These results show clear axes of selectivity both dorsal-ventrally and anteriorly-posteriorly. Working memory training has been shown to affect the response properties of the PFC in many tasks, thus in order to examine if the properties along these axes were altered following training in a working memory task, we recorded from four of the same monkeys after they had acquired a match/nonmatch task rule. We then observed that there was an increase in selectivity primarily in the anterior regions of the dorsal PFC and that the dorsal regions still carried more spatial information than ventral regions. Furthermore, there was a gradient of decoding selectivity for the task rule during the sample and sample delay periods in the dorsal PFC where the anterior-dorsal region had the highest decoding accuracies right before the decision was made. Our results provide much needed clarification on the functional specialization of the PFC and alterations from working memory training.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2017

Author dc:creator

• Riley, Mitchell

• functional specialization

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10339/82194

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/82194