Alterations in the density of excrescences in CA3 neurons of hippocampus in rats subjected to self-stimulation experience.

Self-stimulation (SS) rewarding experience induced alterations in the density of excrescences in the apical dendrites of CA3 neurons were studied in adult male Wistar rats. SS experience was provided daily for an hour over a period of 10 days, through bipolar stainless steel electrodes implanted bilaterally in lateral hypothalamus and substantia nigra-ventral tegmental area. The results revealed a significant (P<0.001) increase in the number of excrescences in both main shaft and sub branches of the apical dendrites in SS experienced group compared to control groups of rats. The increased number of excrescences in CA3 neurons might be due to an enhancement in the synaptic transmission in the mossy fiber pathway following SS experience.