# Activity-dependent dendrite patterning in the postnatal barrel cortex

## TL;DR

This review discusses how newborn neurons in the rodent brain reshape their connections based on activity, focusing on the barrel cortex and how sensory input influences dendrite patterning.

## Contribution

The paper highlights new insights into activity-dependent Golgi apparatus polarity regulation and in vivo imaging techniques in dendrite patterning.

## Key findings

- In vivo time-lapse imaging reveals activity-dependent mechanisms of dendrite patterning in barrel cortex neurons.
- Activity-dependent Golgi apparatus polarity regulation plays a role in dendrite patterning and circuit reorganization.
- Neuronal activity, particularly from thalamocortical inputs, drives dendrite remodeling in neonatal barrel cortex neurons.

## Abstract

For neural circuit construction in the brain, coarse neuronal connections are assembled prenatally following genetic programs, being reorganized postnatally by activity-dependent mechanisms to implement area-specific computational functions. Activity-dependent dendrite patterning is a critical component of neural circuit reorganization, whereby individual neurons rearrange and optimize their presynaptic partners. In the rodent primary somatosensory cortex (barrel cortex), driven by thalamocortical inputs, layer 4 (L4) excitatory neurons extensively remodel their basal dendrites at neonatal stages to ensure specific responses of barrels to the corresponding individual whiskers. This feature of barrel cortex L4 neurons makes them an excellent model, significantly contributing to unveiling the activity-dependent nature of dendrite patterning and circuit reorganization. In this review, we summarize recent advances in our understanding of the activity-dependent mechanisms underlying dendrite patterning. Our focus lays on the mechanisms revealed by in vivo time-lapse imaging, and the role of activity-dependent Golgi apparatus polarity regulation in dendrite patterning. We also discuss the type of neuronal activity that could contribute to dendrite patterning and hence connectivity.