Failures of cognitive control or attention? The case of stop-signal deficits in schizophrenia

Abstract

We used Bayesian cognitive modelling to identify the underlying causes of apparent inhibitory deficits in the stop-signal paradigm. The analysis was applied to stop-signal data reported by Badcock et al. (Psychological Medicine 32: 87-297, 2002) and Hughes et al. (Biological Psychology 89: 220-231, 2012), where schizophrenia patients and control participants made rapid choice responses, but on some trials were signalled to stop their ongoing response. Previous research has assumed an inhibitory deficit in schizophrenia, because estimates of the mean time taken to react to the stop signal are longer in patients than controls. We showed that these longer estimates are partly due to failing to react to the stop signal (“trigger failures”) and partly due to a slower initiation of inhibition, implicating a failure of attention rather than a deficit in the inhibitory process itself. Correlations between the probability of trigger failures and event-related potentials reported by Hughes et al. are interpreted as supporting the attentional account of inhibitory deficits. Our results, and those of Matzke et al. (2016), who report that controls also display a substantial although lower trigger-failure rate, indicate that attentional factors need to be taken into account when interpreting results from the stop-signal paradigm.

Abnormal neural functions associated with motor inhibition deficits in schizophrenia and bipolar disorder

“…Thus, findings suggest that the observed deficits in motor inhibition in schizophrenia patients are in part due to slowed processes that precede motor activation. For example, there has been recent evidence to suggest that schizophrenia patients demonstrate deficient response inhibition in part due to abnormalities in stimulus processing (Hoptman et al, 2018;Matzke, Hughes, Badcock, Michie, & Heathcote, 2017 (Zandbelt et al, 2011). Given the different approaches to analysis reported by these previous studies and the current study, care should be taken in comparing our results with those of Vink et al (2006) and Zandbelt et al (2011).…”

“…For example, there has been recent evidence to suggest that schizophrenia patients demonstrate deficient response inhibition in part due to abnormalities in stimulus processing (Hoptman et al, 2018;Matzke, Hughes, Badcock, Michie, & Heathcote, 2017). Thus, findings suggest that the observed deficits in motor inhibition in schizophrenia patients are in part due to slowed processes that precede motor activation.…”

Reconsidering electrophysiological markers of response inhibition in light of trigger failures in the stop-signal task

“…While adjustments to traditional SSRT estimation methods have been developed to account for omissions rates on go trials, as a close proxy for go failures (e.g., Tannock, Schachar, Carr, Chajczyk, & Logan, 1989), simulations suggest this method over-estimates SSRT . Trigger failure (failure to initiate the stop process) has long been acknowledged as possible (e.g., Logan, 1994), yet it is not taken into account in non-parametric methods of estimating SSRT (see Verbruggen & Logan, 2009) and not accounting for trigger failure has been shown to bias estimates of SSRT in a growing number of studies (Band et al, 2003;Matzke, Curley, et al, 2019;Matzke, Hughes, et al, 2017;Matzke, Love, et al, 2017;Skippen et al, 2019). More generally, it is important to acknowledge that effective inhibitory control relies not only on fast SSRT, but also on the reliability of triggering the stop process (Chatham et al, 2012;Matzke, Love, et al, 2017).…”

“…The practical importance of modelling trigger and go failures has been highlighted in a number of studies (Band et al, 2003;Matzke, Curley, et al, 2019;Matzke, Dolan, et al, 2013;Matzke, Hughes, et al, 2017;Skippen et al, 2019;Weigard, Heathcote, Matzke, & Huang-Pollock, 2019). For example, Skippen et al (2019) found that the SSRT estimate derived from the EXG3 model was reduced by ≈100ms compared to the estimate obtained using the traditional non-parametric integration method (e.g., Tannock et al, 1989).…”

“…Increased SSRT is seen as representing less efficient response inhibition, resulting in reduced impulse control (but see, Sharma, Markon, & Clark, 2014;Skippen et al, 2019). However, the purity of SSRT as the measure of inhibitory cognitive control has recently been increasingly questioned (Band, Van Der Molen, & Logan, 2003;Logan, 1994;Matzke, Curley, Gong, & Heathcote, 2019;Matzke, Hughes, Badcock, Michie, & Heathcote, 2017;Matzke, Love, & Heathcote, 2016;Matzke, Love, & Heathcote, 2017;Skippen et al, 2019;Verbruggen, Best, Bowditch, Stevens, & McLaren, 2014;Verbruggen, McLaren, & Chambers, 2014).…”