Visual hemineglect is characterized by the inability to perceive, respond or orient towards stimuli presented in the visual hemispace contralateral to a unilateral lesion, most commonly the right posterior parietal area in humans. Despite intact primary sensory input and motor output, patients only consciously perceive and respond to the ipsilateral visual space. Extinction is a phenomenon frequently seen in unilateral hemineglect, where patients only fail to respond to stimuli in the contralesional hemispace when these co-occur simultaneously with stimuli in the ipsilesional hemispace. Little is known about the neuronal mechanisms causally involved in neglect and extinction. Previous studies in rodents have shown that disrupting prefrontal areas (Christakou et al., 2005; Ishii et al., 2021) and dorsal striatum (Christakou et al., 2005) induces neglect-like symptoms. However, a model which allows for close control of visual input and motor deficits is lacking. Therefore, we aimed to develop a head-fixed mouse model of visual hemineglect and identify causally relevant areas in the dorsal cortex. We developed a novel Go/No-Go visual extinction task, in which head-fixed mice have to respond whenever a left-side stimulus is shown either alone, or together with a right-side stimulus, while ignoring right-side stimuli. To identify regions of interest we used laser-scanning optogenetics in VGAT-ChR2 animals (n=4). We unilaterally inhibited 21 regions in the right dorsal cortex during task-performance. Preliminary data show that inactivation of posterior and frontal areas induces differential deficits in target detection and stimulus discrimination. This suggests widespread cortical involvement in spatial visual detection.