Experimental neurology
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Experimental neurology · Oct 2016
Transient loss of consciousness during hypercapnia and hypoxia: Involvement of pathways associated with general anesthesia.
Transient loss of consciousness (TLOC), frequently triggered by perturbation in essential physiological parameters such as pCO2 or O2, is considered a passive consequence of generalized degradation in high-level cerebral functioning. However, the fact that it is almost always accompanied by atonia and loss of spinal nocifensive reflexes suggests that it might actually be part of a "syndrome" mediated by neural circuitry, and ultimately be adaptive. Widespread suppression by molecules distributed in the vasculature is also the classical explanation of general anesthesia. ⋯ The results implicate neurons in a specific common-core region of the MPTA in TLOC induced by both forms of asphyxia. This is the same area responsible for general anesthesia induced by GABAergic anesthetic agents. This implies the involvement of a common set of brain nuclei and dedicated axonal pathways, rather than nonspecific global suppression, in the mechanism mediating all three instances of TLOC.