BDNF and Stroke: Analysis of BDNF expression in the bilateral motor and ipsilesional sensory cortex, a brain region critical for post-stroke recovery (34), revealed a significant increase in BDNF expression in both astrocytes and neurons in the OptoSTIM1 group, suggesting that enhanced synaptic plasticity mediated by astrocyte calcium modulation may play a key role in post-stroke recovery (Fig. 5, D to H, and fig.