Self-stimulation rewarding experience induced alterations in dendritic spine density in CA3 hippocampal and layer V motor cortical pyramidal neurons

Self-stimulation rewarding experience induced alterations in the numerical density of spines in CA3 hippocampal and layer V motor cortical pyramidal neurons in adult male Wistar rats was evaluated. Self-stimulation experience was provided 1 h daily over a period of 10 days through stereotaxically implanted bipolar stainless steel electrodes bilaterally in lateral hypothalamus and substantia nigra-ventral tegmental area. After 10 days, rats were killed and the hippocampus and motor cortex were processed for rapid Golgi staining procedure. The dendritic spine densities were studied in CA3 hippocampal and layer V motor cortical pyramidal neurons. The spine densities were quantified in five successive segments of 15.2 μm up to a distance of 76 μm. Apical dendrites were classified as mainshaft, sub branch, oblique shaft-I, oblique shaft-II, primary branch; and basal dendrites as main shaft, primary branch and secondary branch. A grand total of 864 CA3 hippocampal and 1 008 layer V motor cortical dendrites were analysed for spine counting in different groups of rats. The results revealed a significant ( P