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Neurons for activity transition in brain development identified


Specific subclasses of interneurons identified as the key modulators of neuronal activity transition in the developing brain.

SST+ and PV+ interneurons are responsible for the transition between early and adult patterns of neuronal activity, which allows for the maturation of the brain and the integration and processing of sensory information.

Scientists from the Marín lab published a study in Neuron that identified two subclasses of interneurons as instructors of a key developmental process in the brain.

During early development after birth, brain networks are characterised by bursts of activity that synchronise a large number of neurons. As the brain matures, this activity pattern changes in rhythm, frequency, and amplitude to become asynchronous, where only a small number of neurons are simultaneously active. These changes allow the brain to process and adapt to the vast amount of information received by our senses.

Although this transition between patterns of neuronal activity is a crucial milestone in brain development, the cellular mechanisms behind this process remain poorly understood. In this study, the Marín Group sought to investigate the key players behind this transition.

The early developing brain produces excitatory and inhibitory neurons, but inhibitory processes appear later than the excitatory ones. The progressive maturation of inhibition, correlated with the progressive maturation of interneurons, dictates the maturation of the brain and its adaptation to environmental cues.

The scientists identified the specific interneurons responsible for the modulation of network activity in the first two weeks of postnatal development in mice. SST+ interneurons generate synchronous patterns of neuronal activity, whereas PV+ interneurons are responsible for the transition to an asynchronous pattern of activity. However, SST+ interneurons control in part the maturation of PV+ interneurons and thus instruct the timing of this transition. Therefore, SST+ interneurons are identified as critical regulators of neuronal dynamics in the developing brain, and preventing them from carrying their action leads to a delay in brain maturation.

We have identified how specific subclasses of interneurons integrate and regulate a key stage in brain development. These interneurons, SST+ and PV+ interneurons, have also been associated with several neurodevelopmental conditions. These findings indicate that we need to further look at these interneurons to better understand these conditions.

Professor Oscar Marín