DENDRITIC RIGHT/LEFT ASYMMETRIES IN THE NEURONS OF THE HUMAN HIPPOCAMPAL FORMATION

ABSTRACT- Objective: To search for right/left asymmetries in the dendritic trees of the neuronal popula-tions and in the cell-free layer volumes of the human hipoccampal formation. Method: In necropsic ma-terial obtained from six male individuals we performed a quantitative Golgi study of the dendritic trees of dentate granules, CA3 and CA1 pyramidal neurons and a volumetric analysis of dentate gyrus molecular lay-er, strata oriens plus alveus and strata lacunosum-moleculare plus radiatum of CA3 and CA1 fields. Results: We found inter-hemispheric asymmetries in the dendrites trees of all neurons, reaching the significant lev-el in the number of granule cells dendritic segments (higher in the left than in the right hemisphere), den-dritic branching density of CA3 pyramidal cells and mean dendritic length of CA1 apical terminal segments (higher in the right than in the opposite side). No volumetric differences were observed. Conclusion: This study points to different anatomical patterns of connectivity in the hippocampal formations of both hemi-spheres which may underlie functional asymmetries. KEY WORDS: brain asymmetries, hippocampal formation, dendritic asymmetries. Assimetrias dendríticas direita/esquerda nos neurónios da formação do hipocampo humano: estudo quan