Genetic variation in the serotonin transporter gene influences ERP old/new effects during recognition memory

Abstract

Recognition memory is defined as the ability to recognize a previously encountered stimulus and has been associated with spatially and temporally distinct event related potentials (ERPs). Allelic variations of the serotonin transporter gene (SLC6A4) have recently been shown to impact memory performance. Common variants of the serotonin transporter-linked polymorphic region (5HTTLPR) of the SLC6A4 gene result in long (l) and short (s) allelic variants with carriers of the s allele having lowered transcriptional efficiency. Thus, the current study examines the effects polymorphisms of the SLC6A4 gene have on performance and ERP amplitudes commonly associated with recognition memory. Electroencephalogram (EEG), genetic, and behavioral data were collected from sixty participants as they performed an item and source memory recognition task. In both tasks, participants studied and encoded 200 words, which were then mixed with 200 new words during retrieval. Participants were monitored with EEG during the retrieval portion of each memory task. EEG electrodes were grouped into four ROIs, left anterior superior, right anterior superior, left posterior superior, and right posterior superior. ERP mean amplitudes during hits in the item and source memory task were compared to correctly recognizing new items (correct rejections). Results show that s-carriers have decreased mean hit amplitudes in both the right anterior superior ROI 1000–1500 ms post stimulus during the source memory task and the left anterior superior ROI 300–500 ms post stimulus during the item memory task. These results suggest that individual differences due to genetic variation of the serotonin transporter gene influences recognition memory.

Individual differences in EEG correlates of recognition memory due to DAT polymorphisms

“…Groups of electrodes were averaged together to form regions of interest (ROI; Figure ), similar to what has been done by other researchers (Ally & Budson, ; Norman, Tepe, Nyhus, & Curran, ; Ross et al., ). Our analyses were focused on the left anterior superior (LAS), right anterior superior (RAS), left posterior superior (LPS), right posterior superior (RPS), and right fronto‐polar (RFP) ROIs.…”

“…Groups of electrodes were averaged together to form regions of interest (ROI; Figure 2), similar to what has been done by other researchers (Ally & Budson, 2007;Norman, Tepe, Nyhus, & Curran, 2008;Ross et al, 2015). Our analyses were focused on the left anterior superior & Piatt, 2006;Norman et al, 2008;Rugg et al, 1998)…”

MAO-A Phenotype Effects Response Sensitivity and the Parietal Old/New Effect during Recognition Memory

“…Participants for the study were recruited from the University of Colorado Boulder community. Data from these same participants examining how the 5HTTLPR serotonin transporter polymorphism affects ERP’s and how dopamine transporter polymorphisms affect ERP’s and oscillatory power during recognition memory has been reported elsewhere (Ross et al, 2015 ; Medrano et al, 2017 ). Participants were given monetary compensation for their participation.…”

“…We analyzed the item and source data using groupings of seven electrodes for different scalp locations (regions of interest, ROIs) within specific timeframes (Figure 2 ), similar to our past approach (Norman et al, 2008 ; Nyhus and Curran, 2009 ; Ross et al, 2015 ). We examined four ROIs and three time frames due to their relevance to ERP effects related to recognition memory.…”

“…Personalized treatment for cognitive disruptions related to mental disorders relies on developing an understanding of individual differences in cognition. Genetic variation may be one component driving individual differences in cognitive ability (Friedman et al, 2008 ; Stelzel et al, 2010 ; Barnett et al, 2011 ; Markett et al, 2011 ; van Holstein et al, 2011 ; Colzato et al, 2013a , b ; Ross et al, 2015 ). One gene that has been linked to symptoms of mental disorders, such as depression (Dannlowski et al, 2009 ) and anxiety (Tadic et al, 2003 ) as well as cognitive abilities, including episodic memory (Mueller et al, 2014 ), is the monoamine oxidase A gene ( MAO-A ).…”