Ischemia
The word "ischemia" () is from Greek ἴσχαιμος "iskhaimos", "staunching blood" from ἴσχω "iskhο", "keep back, restrain" and αἷμα "haima", "blood".
Mechanism of anoxic depolarization in the brain
While basal ganglia, cerebellar purkinje cells, hippocampal, and neocortical cells are more vulnerable to transient ischemic attack (TIA), brainstem and thalamic reticular neurons are more vulnerable to prolonged ischemic attack (stroke proper). Meanwhile, the hippocampal pyramidal cells have been identified as the most vulnerable cells to ischemia. One possible explanation for why selective vulnerability exists attributes the phenomenon to the different amounts of glutamate produced by different neurons, since it is glutamate release to the synaptic cleft that triggers Ca influx, which in turn triggers biochemical processes that damage the neurons. In other research, variation in the expression of immediate early gene and heat shock protein was identified as causing selective vulnerability.