Neural Correlates Of Visual And Auditory Working Memory In Prefrontal Cortex

Working memory is the process of maintaining a limited amount of information in an active representation for a brief period of time so that it is available for use.The prefrontal cortex(PFC)is known to play an important role in working memory.A lot of work is done in researching the mechanism of working memory,however,there are some issues we know little about.First of all,most researches are focused on visual working memory rather than auditory working memory.Secondly,the prefrontal cortex receives sensory inputs from multiple modalities,such as visual,auditory,tactile etc.,and deeply engages in performing cognitive tasks.So what's the cognitive correlation when PFC neurons involved in visual and auditory working memory tasks? Using mice as animal model,we examine this question when they perform the task of auditory working memory.Then we analyzed the data to examine the relationship between neuronal electrical activity and animal behavior.Results show that in the animal auditory working memory task,a part of the prefrontal cortex neurons not only react to auditory stimuli,but also maintain a high discharge in delay period,when the first stimulation is finished.It suggests that neurons in the prefrontal cortex may be involved in transient storage of auditory information during delay period in working memory.This is consistent with previous studies of visual working memory.In order to answer the second question in this paper,we trained the well trained mice in the previous task with visual orientation discrimination task.We adopt the method of in vivo multi electrode recording in the animal to record the prefrontal cortex neurons after the animals learned both tasks.Our results indicate that the vast majority(78%)neurons in prefrontal cortex discharge highly in delay period,perform a high discharge both in visual working memory and auditory working memory during delay period,only a small number of neurons involved in auditory memory tasks only(13%),or visual working memory tasks only(9%).It strongly suggests that most of prefrontal cortex neurons are both involved in visual working memory and auditory working memory tasks.The results reinforce our understanding of the prefrontal cortex and how it works,and also lays the foundation for further research on the neural mechanism of brain cognitive function.