**5. Conclusions**

Dendritic spines are small protrusions on the dendritic shaft as major excitatory inputs site on the excitatory neurons in the adult cortex. Spines play critical roles in the excitatory synaptic transmission and plasticity. Genesis of spines occurs during brain development, and is subjected to activity-dependent modulation to determine their fates, either to transit to mature spines or be eliminated. Spines are the site where physiological/functional and morphological/structural modifications meet and integrate, during both physiological (such as memory formation) and pathological (such as neurodegeneration) processes. Interestingly, early changes in functional and structural aspects of synapse modification occur independently, but they subsequently interact with each other to sustain changes in both. This highly interactive nature ensures that the end result is a coherent modification of synapse function and structure. Extensive progress has been made on our understanding of the structure and function of spine which vastly has advanced our understanding of neuronal and synaptic communication and plasticity. In addition, changes in spine density and dimension may serve as a marker of pathological processes and hence have potential therapeutic/diagnostic values.
