Neuropsychological evidence of the functional integration of visual, auditory and proprioceptive spatial maps

We infer the functional integration of the visual, auditory and proprioceptive spatial maps from the behaviour of a patient (G.A.) with left visual neglect, i.e. a derangement of visual space representation. G.A. was required to point manually to left, centre or right acoustic stimuli, under visual control or blindfolded, with the responding hand (left or right) located either on the left, centre or right space. G.A.'s manual pointing responses to left auditory stimuli were strongly influenced by the visual spatial information and by the proprioceptive spatial information related to the position of the responding effector. In the visual control condition, when the patient performed the task with the left effector located on the left, pointing responses to left auditory stimuli were shifted towards the right intact visual space. In contrast, when the visual spatial information was rendered less salient, i.e. in the blindfolded condition, and the effector was again located on the left, manual pointing responses were confined to the previously ignored left space. These findings are consistent with the view that the acoustic representation is modulated by the impaired visual representation and by the proprioceptive spatial map related to the position of the responding effector.