An electrophysiological insight into visual attention mechanisms underlying schizotypy

Abstract

A theoretical framework has been put forward to understand attention deficits in schizophrenia (Luck SJ & Gold JM.. Biological Psychiatry. 2008; 64:34-39). We adopted this framework to evaluate any deficits in attentional processes in schizotypy. Sixteen low schizotypal (LoS) and 16 high schizotypal (HiS) individuals performed a novel paradigm combining a match-to-sample task, with inhibition of return (using spatially uninformative cues) and memory-guided efficient visual-search within one trial sequence. Behavioural measures and Event-related potentials (ERPs) were recorded. Behaviourally, HiS individuals exhibited a spatial cueing effect while LoS individuals showed the more typical inhibition of return effect. These results suggest HiS individuals have a relative deficit in rule selectionthe endogenous control process involved in disengaging attention from the uninformative location cue. ERP results showed that the late-phase of N2pc evoked by the target stimulus had greater peak latency and amplitude in HiS individuals. This suggests a relative deficit in the implementation of selection -the process of focusing attention onto target features that enhances relevant/suppresses irrelevant inputs. This is a different conclusion than when the same theoretical framework is applied to schizophrenia, which argues little or no deficit in implementation of selection amongst patients. Also, HiS individuals exhibited earlier onset and greater amplitude of the mismatch-triggered negativity component. In summary, our results indicate deficits of both control and implementation of selection in HiS individuals.

Schizotypy and auditory mismatch negativity in a non-clinical sample of young adults

“…In a study of treatment-refractory schizophrenia, in conjunction with atypical topography, larger frequency MMN amplitude was also observed in patients relative to controls (Milovan et al, 2004), which in light of the component's unusual topography may indeed reflect compensatory processing. More recently, a visual component similar to the auditory MMN was also enhanced in high compared to low scorers on the O-LIFE questionnaire (Mason and Claridge, 2006) which the authors also argue might reflect compensatory processes due to deficient executive functioning (Fuggetta et al, 2015).…”

Attentional selection and suppression in children and adults

“…() also demonstrated that adult individuals with better top‐down control showed higher amplitudes of the posterior contralateral negativity (in the N2pc domain) than individuals with poorer top‐down control. Moreover, N2pc latency was prolonged in adults with ADHD (Cross‐Villasana et al., ) as well as highly schizotypal adults (Fuggetta, Bennett, & Duke, ). N2pc amplitude was reported to be reduced in children with low working memory capacity (Shimi et al., ), children with ADHD (Wang et al., ) and adults with schizophrenia (Verleger, Talamo, Simmer, Smigasiewicz, & Lencer, ).…”

The development of attentional control mechanisms in multisensory environments

“…There is evidence that N2pc may not be optimal to detect distractor processing even in adults (Eimer et al, 2009). This, coupled with a wealth of evidence for the viability of the N2pc as a marker of target-based attentional selection that is sensitive to healthy development (Wiegand et al 2017;Shimi et al, 2015), aging (Pagano et al, 2015;Wiegand et al, 2013), as well as mental disorders (Fuggetta et al, 2015;Wang et al, 2016), prevents concluding that the N2pc is suboptimal to detect real-world attentional control. Nonetheless, had our analyses stopped at a canonical N2pc approach, one could have concluded that attentional control processes like TAC and MSE are simply not elicited by goal-irrelevant stimuli (cf.…”