New research reveals a sophisticated brain mechanism that is critical for filtering out irrelevant signals during demanding cognitive tasks.
The study, published by Cell Press in the February 26 issue of the journal Neuron, also provides some insight into how disruption of key inhibitory pathways may contribute to schizophrenia.
"The ability to keep track of information and one's actions from moment to moment is necessary to accomplish even the simple tasks of everyday life," explains senior study author, Dr. Helen Barbas from Boston University and School of Medicine. "Equally important is the ability to focus on relevant information and ignore noise."
Dr. Barbas and colleague, Dr. Maria Medalla, were interested in examining the synaptic mechanisms for selection and suppression of signals involved in working memory. They focused on the fine synaptic interactions of pathways with excitatory and inhibitory neurons in brain areas involved in attention.
"The primate dorsolateral prefrontal cortex (DLPFC) and anterior cingulated cortex (ACC) are brain regions that focus attention on relevant signals and suppress noise in cognitive tasks. However, their synaptic communication and unique roles in cognitive control are largely unknown," explains Dr. Barbas.
The researchers found that a pathway linking two related prefrontal areas within DLPFC and a pathway from the functionally distinct ACC to DLPFC similarly innervated excitatory neurons associated with paying attention to relevant stimuli. Interestingly, large nerve fiber endings from ACC contacted selectively inhibitory neurons that help suppress "noisy" excitatory neurons nearby.