**Abstract**

Oxytocin receptor (OXTR) gene polymorphisms have been consistently associated with humans' differences in sensitivity to social cues, social cognition, stress response, and brain activity. However, how social and affective neural processing differs across carriers of distinct OXTR gene polymorphisms remains unclear. This systematic PRISMA review is the first to examine the experimental literature on the relationship between OXTR polymorphisms and ERP components. Eight studies published between 2014 and 2019 were included. The rs53576 was the only OXTR gene polymorphism analyzed in all studies. The OXTR genetic variation explained significant changes in N1, P2, N2, P3, and late positive potential (LPP) components during social perception and empathy for pain tasks. OXTR genotypes were not related to P1, N170, N3, or any neural activity after 600 ms. The discussion is focused on the influence of OXTR genetics on neural processing, the development of brain neural networks implicated in social and emotional skills, cultural neuroscience of the oxytocinergic system, and methodological issues of this field. In conclusion, the evidence supports the hypothesis that genetic variations of the OXTR significantly influence neural activity related to emotional and social processing, except for the early phases of face recognition.

**Keywords:** oxytocin, OXTR gene polymorphism, event-related potentials, social skills, affective processing

## **1. Introduction**

Oxytocin is a neuropeptide that is implicated in relational phenomena such as maternal behaviors, social bonding, emotional communication, caring for others, and social cognition [1, 2]. Further, thanks to evidence from research involving nonhuman animal models [3], intranasal administration [3, 4], developmental psychopathology [5], genetic variations [6], and translational approaches [7], we now know

that oxytocin supports the development of socioemotional skills such as perception of social cues, biobehavioral synchrony, regulation of emotions, prosocial concern, perspective taking, and empathy.

In the last decades, researchers have grown aware of the importance of oxytocin receptor (OXTR) gene polymorphisms in explaining individual and demographic variations in the development of social behaviors [6]. All OXTR polymorphisms identified thus far are single nucleotide polymorphisms (SNP), with the most studied SNP being a guanine (G) to adenine (A) substitution in the locus rs53576. These SNPs have been repeatedly associated with differences in sensitivity to social cues, regulation of stress response, social cognition, and brain activity during social tasks [8, 9]. However, some recent research has failed to find differences in emotional traits between carriers of the alleles for this polymorphism. However, some recent research has not found differences in emotional traits between carriers of the alleles of this polymorphism [10], which raises the question of whether genetic variations in the OXTR gene lead to variations in the brain's processing of socioemotional signals.

Event-related potentials (ERPs) may lend a hand to this endeavor. ERPs are used as a reliable and safe method to examine the human neurophysiological activity related with psychological processing [11]. ERPs are changes in the electroencephalogram of a person, which are time-locked to cognitive, motor, affective, and social events presented during rigorously controlled tasks. ERPs require meticulous experimental control, making it easier to establish a fine-grained analysis of the time dynamics of the brain during the processing of specific aspects of stimuli, which can limit the establishment of broader functional analyses. However, it is justified to inquire about the ERP as it is one of the methodological approaches with the most outstanding reputation within cognitive neurosciences since it allows consolidating in greater detail how our brain constructs psychological phenomena [12].

ERPs are analyzed in terms of components that can be studied as a window into the neurophysiological mechanisms associated with ongoing mental activity. These components are built by using the polarity, latency, and scalp distribution of ERP waveforms and by considering the specific conditions of each experimental task [13, 14]. For example, in socio-affective tasks, frequently analyzed components include N170, early posterior negativity (EPN), and late positive potential (LPP). The first is an inferior negative wave, appearing approximately 170 ms after a face is shown; the second is occipital-parietal activity occurring around 200 ms after the display of images with affective content; and the last is anterior brain activity appearing shortly after 500 ms following the perception of arousing stimuli.

Accordingly, it is expected that carriers of distinct OXTR polymorphisms exhibit differences in neural processing, as measured by ERPs, during diverse psychological tasks. However, a systematic review of the studies that have examined the relationship between OXTR polymorphisms and ERP components has not been conducted so far. Such a review is valuable because it will allow for a better understanding of how genetic variations in the oxytocinergic system can lead to neurophysiological and behavioral differences. Additionally, it will be useful in guiding future investigations by identifying points of interest and questions to be answered. Therefore, our main aim is to review systematically the literature that has studied the relationship between OXTR polymorphisms and ERP components elicited during psychological tasks.

*OXTR Gene Polymorphisms and Event-Related Potentials in Humans: A Systematic Review DOI: http://dx.doi.org/10.5772/intechopen.112631*
