Cognition is complex attribute of the brain encompassing the functions of memory, decision, language, attention, gnosis, orientation, praxis, visuospatial skills, executive functions, and social cognition. It is the function of neuronal network in the central nervous system (CNS) and pertaining neurotransmitter modulation. Neurotransmitters are chemical messengers packaged in vesicles at presynaptic terminals. The communication process is regulated in the specialized areas of the plasma membrane called active zones. Neuromodulation has further evolved to allow for the flexibility in the dynamically updating the effectivity of the static anatomical connectivity and cognitive functions. Psychiatric and developmental disorders which compromise the cognitive ability have been linked with the variabilities of CNS such as synaptic plasticity, hippocampal health, epigenetic modification, epigenetic priming, hemispheric symmetry, prefrontal cortex, etc. Neuromodulators such as histone deacetylase inhibitors, retinoic acid receptor activators, and neuroplasticity enhancers can reverse the effect of neurodegeneration, aging, autism, schizophrenia, and other psychiatric disorders. There are several phytochemicals such as vitamin A, valproate, flavonoids, monoterpenes, and peppermint which works as neuromodulators or cognitive enhancers.