Neural Correlates Of Auditory Working Memory Decline In Aged Mice

To reveal the neural correlates of Working memory(WM)decline in aged mice,we recorded the neural activity of Auditory cortex(AC)neurons when the normal adult and aged mice performed an auditory frequency discrimination working memory task.Our study revealed that aged mice can learn the rule of the working memory task,however,the performance was not as good as the adult mice.In the adult mice,when the animal was performing the auditory working memory task,the neurons in auditory cortex keep firing even after the end of the first sound stimuli in the delay period of the working memory task.This delay period activity last about 1 second.Further experients showed that in the similar auditory working memory task with a longer delay period(3s and 7s),the neurons in auditory cortext also keep firing after the end of the first sound stimuli in the delay period and last about 1 second.These result indicated that the auditory cortex involed in the temporal storage of audtory sensory information in the delay period of auditory working memory task.However,study in the aged mice showed that,the neural activity of the auditory cortex neurons in the delay period was much lower than adult mice when the animal was performing auditory working memory task.When we extended the delay period of the working memory task to 3s and 7s,we got the same results.These results suggested that the decline in age-related working memory was not only related to the prefrontal cortex(PFC)as reported previously,but also related to the auditory cortex(AC).The neural basis for the decline of working memory in aged animals involves the change of the neural circuits underlying working memory.