Prefrontal cortex contributions to visual-spatial working memory

Objective To investigated visual-spatial working memory deficits in patients with focal brain damage involving different subregions of the prefrontal cortex.Methods Twenty patients with lesions in the prefrontal cortex and 20 healthy controls performed visual-object and visual-spatial working memory tasks,including a face-recognition and a spatial delayed-response.Results Compared with health controls (72.9%±6.1%),patients with lesions in ventral prefrontal cortex(VPFC) demonstrated an impairment of a face-recognition task(46.4%±11.4%,U=1.00,P<0.01);Patients with lesions in dorsolateral prefrontal cortex (DLPFC) showed impairment on both visual-object and visual-spatial working memory tasks (50.4%±15.1%,72.6%±18.6%,respectively),indicating significant reduced in a compare to controls (72.9%±6.1%.89.4%±10.1%,U=-20.5,59.5,both P<0.01).There wag no difference in two working memory tasks between patients with lesions in left prefrontal cortex and patients with lesions in right prefrontal cortex:and between patients with lesions in left VPFC and patients with lesions in right VPFC.Patients with lesions in left DLPFC and those in right DLPFC also didn't show significant difference on performance in object or spatial working memory.Conclusions The results confirmed that patients with lesions in prefrontal cortex had deficits of visual-spatial working memory.The results also supported a separation of function with the prefrontal cortex into two distinct subregions for visual-spatial working memory. Key words: Brain injuries; Prefrontal cortex;  Memory disorders;  Space perception; Neuropsychological tests