Granger causality analysis reveals the changes of thalamocortical functionality after cardiac arrest induced hypoxic-ischemic injury

Hypoxic-ischemia (HI) following cardiac arrest (CA) induces a global injury to the brain that can lead to coma. Resuscitation may eventually lead to arousal from coma. During early arousal, how the functional connectivity between various important brain regions evolves may ultimately affect the outcome. In order to understand the changes in thalamocortical functionality through the injury and recovery periods, we recorded local field potentials (LFPs) from the ventroposterior lateral (VPL) nucleus of the thalamus and the forelimb somatosensory cortex (S1-FL) in a rat model of asphyxial CA. Granger causality was used to analyze the causal relationships between the thalamocortical LFPs. Preliminary results indicate that during early arousal, the thalamocortical dynamics is significantly unilateral with the thalamic centers driving the cortical regions and the driving strength decreased significantly upon CA and improved after resuscitation during arousal.