Maze training effects on dendritic branching in occipital cortex of adult rats

Dendritic branching in occipital cortex was compared in Golgi-stained neurons from adult rats subjected to 26 days of Hebb-Williams maze training (24 trials per day) and littermates subjected to deprivation and daily handling procedures. Distal regions (beyond 250 μm) of the apical dendritics of Layer IV and V pyramidal neurons were more extensively branched in the trained animals, as revealed by both a concentric ring intersection analysis and by measures of the numbers and lengths of oblique branches from the apical dendrite. There were no statistical differences in basal dendritic branching of pyramidal cells or in dendritic branching of Layer IV stellate neurons between the two groups, nor were there consistent differences in the proximal region of apical dendrites. These results are among the first to indicate anatomical plasticity at the neuronal level in adult animals.