Abstract

The present case study documents an unprecedented opportunity for correlative investigation of brain structure and function by quantitatively investigating the basilar dendritic systems of supragranular pyramidal cells in several cortical areas from a subject who had undergone electrical stimulation mapping two years prior to death. Electrical stimulation mapping results provided valuable functional information about the cortical areas removed for postmortem histological analysis. Morphometric analyses distinguished between proximal (1st, 2nd, and 3rd order) and ontogenetically later developing distal (4th order and above) basilar dendritic branches. In general, perisylvian language association stimulation sites (classical Wernicke's and Broca's areas) were characterized by different dendritic patterns than motor strip sites. In primary motor strip tissue blocks, proximal segments were longer than distal segments. In "higher order" elaborative cortical zones, distal segments were longer than proximal segments. Proximal segments outnumbered distal segments in primary motor zones, but the numerical difference between proximal and distal segments was reduced in the association areas. Finally, 4th order segments had significantly more dendritic spines than 3rd order segments in all sites. These dendritic findings suggest a somewhat later ontogenetic development in classical Broca's and Wernicke's areas than in primary motor cortex.

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