Signal transmission is one of the important crucial phenomena responsible for the communication between two different synaptic neurons (pre and postsynaptic neurons) present in a brain region. This signal transmission is carried out by a specific group of chemical substances called neurotransmitters. These neurotransmitters are produced from the metabolic byproducts (precursor neurochemicals) transmitted from the gut to the central nervous system (CNS) through the blood-brain barrier (BBB). Transmitted precursor neurochemicals are further used by the presynaptic neurons for the biosynthesis of neurotransmitters for eliciting signal transmission with postsynaptic neurons. Synthesized neurotransmitters are released into the synaptic cleft for their binding with the postsynaptic neuronal receptors (PNR). The bound neurotransmitter along with the PNR complex further result in the activation of downstream signaling molecules (DSM) involved in various neuronal signaling pathways. Activation of the DSM later results in the formation of cognitive memory against an unexposed stimulus. Formed memory is used by the organism for the differentiation of safe and unsafe stimuli in its living environment. In the present review, we reported the biosynthesis pathways involved in the production of neurotransmitters with the use of neuroactive chemicals and also stated the release and participation of neurotransmitters in the formation of cognitive memory with the help of recent findings. It also showed the effect of neurotransmitters in the development of cognitive dysfunctions. Thus the present review may act as a suitable platform for knowing the interrelationship of neurotransmitters and cognitive memory formation in a precise manner.
M. Murugan (Sun,) studied this question.