INSP-05. Development of fast cortical rhythms in health and mental disease

Synchronization of neuronal activity in fast oscillatory rhythms is a commonly observed feature in the adult cerebral cortex. While its exact functions are still a matter of debate, oscillatory activity in gamma frequency range (20-100 Hz) has been proposed to organize neuronal ensembles and to shape information processing in cortical networks. Gamma activity emerges from reciprocal interactions between excitatory and inhibitory neurons. A fine-tuned balance between excitatory drive and inhibitory feedback is mandatory for circuit function underlying cognitive performance, whereas imbalance between excitation and inhibition and resulting gamma disruption have been proposed to cause cognitive disabilities in psychiatric disorders. Despite extensive investigation of gamma activity in adult brain, its development and function early in life are still poorly understood. The talk will highlight recent experimental findings that uncover the mechanisms and role of fast oscillatory activity throughout development. We will uncover how different neuronal populations interact to generate gamma oscillations. Moreover, we will show that these early oscillations are necessary for the adult cognitive abilities. On the flip side, poorer mnemonic and social abilities that have been characterized in several psychiatric disorders, such as schizophrenia and autism, might result from developmental miswiring of the brain. Our data support this hypothesis by demonstrating that weaker fast oscillatory rhythms, sparser connectivity and lower communication are present in the core circuit of cognitive processing, including the prefrontal cortex, hippocampus and entorhinal cortex, in mouse models of these disorders. Together, these findings highlight the relevance of fast cortical rhythms early in life for the adult brain function.