Figure 2. Results from Makin et al. (2020). The parametric SPN response was evident in 5 tasks (from 5 different groups of 26 participants) but selectively enhanced in the regularity task (left). Figure from Makin et al. (2023).
It is likely that all brain functions are altered by alcohol intoxication, directly or indirectly (Field et al., 2010; Fillmore & Van Selst, 2002). Steele and colleagues (e.g., Steele and Josephs, 1988, Steele and Josephs, 1990) proposed a model of alcohol effects that focused on alcohol’s influence on attentional processes. According to this attention-allocation model, intoxication restricts the focus of attention to only the most salient cues in the environment, such that other available cues are not fully processed (Sayette, 1999). A different model proposed by Vogel-Sprott and colleagues posits that, rather than restricting attentional focus, alcohol impairs a form of response inhibition (e.g. Vogel-Sprott et al., 2001). This model is based on a theory of cognitive control (Logan and Cowan, 1984) positing that behavioural activation and behavioural inhibition stem from two independent cognitive processes.
Acute and chronic effects of alcohol consumption are well studied (for reviews see Creupelandt et al., 2019; Dry et al. 2012; Stavro et al., 2013; Oscar-Berman et al., 2014). Alcohol has many effects on vision: altering eye movement (Marinkovic et al., 2013), contrast sensitivity (Pearson, & Timney, 1998), colour perception (Brazil et al., 2015; Zrenner et al. 1986), retinal image quality and night vision performance (Castro et al., 2014), as well as deteriorating binocular vision (Hogan & Linfield, 1983).
Alcohol usually supresses ERPs, but there is considerable variability between components. A meta-analysis by Fairbairn et al. (2021) found that alcohol reduces ERP components linked with attention (P3b), automatic auditory processing (MMN), and performance monitoring (ERN/FRN). Alcohol also reduces the P300 response negative feedback (Euser et al. 2011) and a temporoparietal N180 that indexes prelexical pattern-recognition processes. In contrast, alcohol may have little, or no effect on components linked to executive control (N2b) or stimulus classification (N2c). Finally, alcohol significantly increasesthe amplitude of the N450, particularly on trials evoking sympathetic arousal (Marinkovic et al., 2006). The current research tested whether the SPN is reduced by alcohol, like many other ERPs.