Which brain structure is most likely affected first by an anoxic insult?

The cortex is most likely affected first by an anoxic insult because it is highly dependent on a continuous supply of oxygen and glucose to function properly. The brain is sensitive to hypoxia, and the layers of the cortex, particularly the pyramidal cells, are among the first to suffer damage when oxygen supply is compromised. This vulnerability is due to the high metabolic demand of cortical neurons and their reliance on aerobic metabolism.

In contrast, other brain structures like the brainstem and spinal cord may display some level of resilience to the effects of anoxia. The brainstem, which controls vital life functions such as breathing and heart rate, has a more primitive neural architecture and can withstand short periods of reduced oxygen levels compared to the neocortex. The spinal cord, while also affected by anoxic conditions, generally experiences damage after the cortical structures. The cerebellum, involved in coordination and motor control, also has a different metabolic profile and tends to be affected later than the cortex during anoxic events.

Thus, in the context of anoxic damage, the cortex is particularly susceptible and is the most likely region to experience initial injury. This difference in vulnerability highlights the critical role that oxygen plays in maintaining the health of brain structures, particularly those involved in higher cognitive functions