Synaptic plasticity of the neocortex of white rats with diffuse-focal brain injuries.

Studies on white mongrel rats addressed the reorganization of the synaptoarchitectonics of layer I of the cerebral cortex in diffuse-focal injuries. The experiments used models of acute arrest of the systemic circulation (clinical death) resulting from exposure to mechanical asphyxia for 6 min, clamping of the common carotid arteries for 20 min (ischemia), and imposition of sublethal rotatory trauma by the Noble-Collip method (craniocerebral trauma). Electron microscopy and morphometric analysis showed that reductions in the total number density of synapses were accompanied by changes in the relative and absolute contents of the major types of synaptic apparatuses. There were increases in the numbers of large simple and perforated contacts and synapses with invaginated synaptic membranes, mitochondria, and spine apparatuses. These changes were interpreted as the structural basis for the mechanisms of synaptic plasticity in diffuse-focal brain injuries.