Lissencephalic Cortex Research Articles

Lisencefalia: Agiria: Un estudio con el metodo de Golgi

A case of lissencephaly (agyria) is reported in which the Golgi stain was used to study the fronto-parietal cortex. The external cellular layer, the so-called true cortex, was shown to be made up of neurons from the 5th and 6th layers of the normal cortex. The neurons in the much less cellular layer were shown to be large pyramidal cells with well-developed dendritic branching and spines. The deeper cellular layer was a neuronal pool without well-defined layering. All the neural forms from the normal cortex were represented. In this layer the inner neurons showed a less advanced stage of development than did those in the outer groups. In the external cellular layer there was a disorganization of neuronal disposition as well. Otherwise typical large and medium-sized pyramidal cells from the outer third showed apical dendrites directed towards deeper structures, and the basal dendrites ran through the marginal layer. Neurons with double dendritic branching and fusiform neurons were present in an abnormal rotated position. In both cases, the axons always showed a descending direction. These findings add to existing knowledge concerning the anatomy of the lissencephalic cortex, although the exact interpretation of the abnormalities found in the external cellular layer remains speculative.

Spreading depression in squirrel monkey lissencephalic cortex.

Abstract Spreading depression was elicited in the squirrel monkey's cerebral cortex to determine some parameters of cortical spreading depression (CSD) in a highly encephalized but semi-lissencephalic brain. Rate of CSD propagation, as indicated by a slow potential (SP) change, was slower than in other mammals but comparable to that reported in other primates. Frontal and occipital regions of the cortex differed in terms of SP amplitude, CSD threshold, SP waveform, and seizure threshold. It was concluded that the squirrel monkey would be an excellent preparation for studying the effects of CSD upon memory functions, interhemispheric transfer, and other phenomena in a highly encephalized brain.