Parietal cortex persistent activity and working memory capacity

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The number of objects that humans can hold simultaneously in memory for a short time (our working memory) is remarkably small. The maximum is thought to be seven, as in the number of digits in a phone number, but the average is about only four! The limited capacity of our working memory depends on neural mechanisms that are distributed in the frontal and parietal lobes of our brain, but the current state of our knowledge is far from complete. On the one hand, only basic memory mechanisms have been studied because there exists no adequate animal model to study working memory capacity. On the other hand, nearly all our knowledge about these basic memory mechanisms has been obtained from studies of the frontal cortex despite all the evidence indicating that the parietal cortex also plays an important role. In this proposal, we will first establish a new animal model to study working memory capacity by adapting a simple procedure that has been extensively used in humans for that purpose. Next, we will study the mostly unexplored neural mechanisms within the parietal cortex by recording the activity of neurons while animals perform this new working memory task. Finally, computer simulations of models built from all the available data will help us formalize our findings and make detailed predictions that can be tested with future experiments. The results of this multi-disciplinary research will have implications for the basic study of information processing taking place within and between neurons within the cerebral cortex, which can be applied to other brain functions, i.e., the limits of our perception and attention. In addition, it will allow students with diverse background - such as biology, psychology, engineering, computer and cognitive science - to gain high quality training in several experimental methods. This research experience will prepare them to enter various areas of research as emerging young leaders, thereby helping to satisfy the increasing demand for highly qualified individuals in academia and industries.