In the developing brain, the functional balance of cortical networks is precisely and finely tuned; imbalance in the ratio of excitatory to inhibitory neurons in cortical networks has been shown to lead to neurodevelopmental disorders such as autism and epilepsy.
In a new publication from the Marín lab published in Cell Reports, Fong Kuan Wong (University of Manchester) and colleagues investigate the mechanisms contributing to this balance in several interneuron subclasses. Wong et al. examine how developmental cell death in neurogliaform cells, bipolar cells and basket cells, the three main populations of interneurons originating from the caudal ganglionic eminence and the pre optic region, is regulated.
The authors found that all three of the interneuron subclasses studied undergo activity-dependent programmed cell death. Interestingly, whilst neurogliaform and basket cells both required glutamatergic transmission to survive, the final number of bipolar cells was conversely modulated by seratonergic signalling.
Wong et al.’s findings show that during the critical period of programmed cell death, input-specific modulation of neuronal activity controls the survival of cortical interneurons. Their findings shed new light on precisely how the balance between excitatory and inhibitory neurons is achieved in the developing brain and contributes to our understanding of the functional balance of cortical networks.