Vitamin B6 acts as an enzymatic cofactor throughout the body, but one of it's roles in cognition is to support neurotransmitter production.
Vitamin B6 helps convert precursor L-DOPA into active dopamine by acting on the enzyme L-dopa decarboxylase. Additionally, vitamin B6 is theorized to provide support for increased dopamine metabolism generated by CREB's heightened transcription of tyrosine hydroxylase, a rate-limiting enzyme that is thought to be one of the major molecular compounds in determining dopamine levels.