Research Report Neuronal substrates of Corsi Block span: Lesion symptom mapping analyses in relation to attentional competition and spatial bias Magdalena Chechlacz a,n , Pia Rotshtein b , Glyn W. Humphreys a a Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK b Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham B15 2TT, UK article info Article history: Received 18 March 2014 Received in revised form 15 September 2014 Accepted 22 September 2014 Available online 2 October 2014 keywords: Corsi Block test Spatial working memory Neglect Voxel-based morphometry abstract Spatial working memory problems are frequently reported following brain damage within both left and right hemispheres but with the severity often being grater in individuals with right hemisphere lesions. Clinically, deficits in spatial working memory have also been noted in patients with visuospatial disorders such as unilateral neglect. Here, we examined neural substrates of short-term memory for spatial locations based on the Corsi Block tapping task and the relationship with the visuospatial deficits of neglect and extinction in a group of chronic neuropsychological patients. Principal Component Analysis (PCA) was used to distinguish shared and dissociate functional components. The neural substrates of spatial short-term memory deficits and the components identified by PCA were examined using whole brain voxel-based morphometry and tract-wise lesion deficits analyses. We found that bilateral lesions within occipital cortex (middle occipital gyrus) and right posterior parietal cortex, along with disconnection of the right parieto-temporal segment of arcuate fasciculus, were associated with low spatial memory span. A single component revealed by PCA accounted for over half of the variance and was linked to damage to right posterior brain regions (temporo-parietal junction, the inferior parietal lobule and middle temporal gyrus extending into middle occipital gyrus). We also found link to disconnections within several association pathways including the superior longitudinal fasciculus, arcuate fasciculus, inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. These results indicate that different visuospatial deficits converge into a single component mapped within posterior parietal areas and fronto-parietal white matter pathways. Furthermore, the data presented here fit with the role of posterior parietal cortex/temporo-parietal junction in maintaining a map of salient locations in space, with Corsi Block performance being impaired when the spatial map is damaged. & 2014 Elsevier Ltd. All rights reserved. 1. Introduction In the human brain working memory operates via large-scale neural networks localized within prefrontal, posterior parietal and medial temporal cortex including the hippocampus (e.g., Fletcher and Henson, 2001; Jonides et al., 1993; Miotto et al., 1996; Owen et al., 1990; Smith and Jonides, 1997; Walter et al., 2003; Wilson et al., 1993). Different sub-regions within these networks control specific processes including the temporary storage of featural and spatial information and the transition of information from short to long term memory (e.g., Abrahams et al., 1999; Bohbot et al., 2002; Constantinidis and Wang, 2004; Courtney et al., 1996; Glabus et al., 2003; Owen et al., 1996a, 1996b, 1996c, 1998; van Asselen et al., 2006). Deficits in short-term visuospatial working memory are often reported following brain injury (e.g., Allen and Larner, 1987; De Nigris et al., 2013; De Renzi et al., 1977; De Renzi and Nichelli, 1975; Kessels et al., 2002a; Malhotra et al., 2009, 2005, 2004; Roth and Crosson, 1985; Wojciulik et al., 2001). Lesions studies in patients as well as functional neuroimaging studies have implicated the role of lateral prefrontal and posterior parietal cortex in short-term spatial working memory (Courtney et al., 1996; Jonides et al., 1993; Malhotra et al., 2009; Mannan et al., 2005). While some of these studies suggest that the neural substrates for spatial working memory are organized bilaterally, others advocate right hemisphere lateralization of spatial working memory resembling the right-lateralization of visuospatial atten- tion (Corbetta and Shulman, 2002, 2011; D’Esposito et al., 1998; Kessels et al., 2002b; Mesulam, 1981; Owen et al., 1996a). There is also a striking overlap between right prefrontal and right posterior parietal regions activated when normal participants perform spatial working memory tests and the lesion location found in visuospatial disorders such as unilateral neglect (diagnosed when Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/neuropsychologia Neuropsychologia http://dx.doi.org/10.1016/j.neuropsychologia.2014.09.038 0028-3932/& 2014 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ44 1865618639; fax: þ44 1865310447. E-mail address: magdalena.chechlacz@psy.ox.ac.uk (M. Chechlacz). Neuropsychologia 64 (2014) 240–251