Sub-components of event related potentials (ERP) associated with polymorphisms in glutamate, gaba and dopamine neurotransmitter receptors

Abstract

Event related potentials (ERPs) reflect perceptual and cognitive processes andtherefore provide an electrophysiological window onto brain function during cognition.P300 component as well as spectral components of ERPs are highly heritable. Potential candidates for the genetic determinants of ERPs are genes encoding several most importantneurotransmitter receptors. In this study, we aimed to identify associations of functionalpolymorphisms of genes encoding glutamate receptor 2A subunit, (NMDAR2A), GABAreceptor gamma-2 subunit (GABRG2) and dopamine receptor D2 subunit (DRD2) with auditory ERPs. EEG recordings and genetic analysis of 72 Turkish male healthy volunteerswere performed in this study. Groups were formed according to their polymorphism typesfor each of the three neurotransmitter receptors. Three cognitive paradigms were designedto generate auditory ERPs. ERP recordings of each polymorphic group were analyzed in the time domain by measuring P300 amplitude and latency, and furthermore, in the timefrequencydomain by decomposition of ERP signals via using wavelet transform withanalysis of variance (ANOVA). Results provide evidence of strong effect of GABRG2polymorphism with ERP characteristics both in time domain and in time-frequency domain. The effects of NMDAR2A and DRD2 polymorphisms are less significant on P300wave. However, time-frequency decomposition of ERP data showed other effects could beobserved in specific frequency bands of all three polymorphisms that were not reflected inthe time-domain representation of the data. The results of this study show that extended analyses on the correlations of genetic differences among normal population onelectrophysiological parameters may extend our view on the genetic basis of cognitive activities.|Keywords: Event Related Potential (ERP), P300, Polymorphism, Receptor, NMDAR2A, GABRG2, DRD2, Time-Frequency Domain Analysis, Wavelet Transform.