“Working memory allows you to choose what to pay attention to, choose what you hold in mind, and choose when to make decisions and take action” says Earl K. Miller, the Picower Professor in MIT’s Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences. “It’s all about wresting control from the environment to your own self. Once you have something like working memory, you go from being a simple creature that’s buffeted by the environment to a creature that can control the environment.”
For years Miller has been curious about how working memory – particularly the volitional control of it – actually works. In a new study in the Proceedings of the National Academy of Sciences led by Picower Institute postdoctoral associate Andre Bastos, his lab shows that the underlying mechanism depends on different frequencies of brain rhythms synchronizing neurons in distinct layers of the prefrontal cortex (PFC), the area of the brain associated with higher cognitive function. As animals performed a variety of working memory tasks, higher frequency gamma rhythms in superficial layers of the PFC were regulated by lower frequency alpha/beta frequency rhythms in deeper cortical layers.
The findings not only suggest a general model of working memory, and the volition that makes it special, but also new ways that clinicians might investigate conditions like schizophrenia where working memory function appears compromised.