Table 3.

Summary of findings from neuropsychological testing of OCD patients on the cognitive tasks discussed in this review

Cognitive process	Cognitive subdomain	Task(s)	Putative underlying brain region(s)	Findings in OCD to date
Inhibitory control	Motor inhibition	Stop-signal task; Go/no-go task	Predominantly a right-sided network including right inferior frontal gyrus, anterior cingulate, frontal, temporal and parietal cortices	Impaired: Bannon et al. (2002, 2006); Chamberlain et al. (2006a, 2007b); Penades et al. (2007) Intact: Bohne et al. (2008)a
	Cognitive inhibition	Stroop task		Impaired: Hartston and Swerdlow (1999); Penades et al. (2005, 2007); Bannon et al. (2002, 2006)
Cognitive flexibility	Attentional set shifting	CANTAB intra- dimensional/extra- dimensional task	Ventrolateral and dorsolateral prefrontal cortex	Impaired: Veale et al. (1996); Watkins et al. (2005); Chamberlain et al. (2006a, 2007b)
	Simple reversal	Object alternation task	Orbitofrontal cortex, medial prefrontal, anterior cingulate, frontal pole	Intact: Nielen and Den Boer (2003)b Impaired: Abbruzzese et al. (1997); Aycicegi et al. (2003) Intact: Katrin Kuelz et al. (2004)
	Probabilistic and reversal learning	Probabilistic reversal learning	Orbitofrontal cortex	Impaired: Remijnse et al. (2006)c Intact: Chamberlain et al. (2007a)
Executive planning		Tower of London	Dorsolateral prefrontal cortex and associated network including premotor cortex, anterior cingulate, precuneus, inferior parietal cortex, caudate and putamen	Impaired: Veale et al. (1996); Nielen and Den Boer (2003); Van den Heuvel et al. (2005); Chamberlain et al. (2007a)
Decision-making		Iowa gambling task	Orbitofrontal cortex and other frontal areas	Impaired: Cavedini et al. (2002) Intact: Nielen et al. (2002)
		Rogers gambling task	Orbitofrontal cortex and other frontal areas	Intact: Watkins et al. (2005); Chamberlain et al. (2007a, b)
Implicit learning		Serial reaction time task	Caudate/ventral striatum, hippocampus, frontal areas	Intact: no between-group behavioural difference but aberrant recruitment of brain regions in an fMRI study (Rauch et al. (2007)

^aLikely due to relative task insensitivity (go/no-go).

^bUnclear how data for subjects ‘failing’ stages were dealt with in this study; exclusion of data for subjects failing a stage is unduly conservative.

^cFewer points accumulated. 50–90% of participants had a co-morbid axis-I mood disorder—a major confound for probabilistic learning (depressive patients show deficits on this task).