Patients with brain damage to the parietal, frontal, and prefrontal cortex often have deficits in spatial working memory and attentional processes. The goal of this investigation is to clarify the function of these various brain regions in the working memory of spatial location and the generation of saccades, or rapid eye movements, toward those locations. There are three specific aims: 1. Determine if retinotopy of visually-guided and delayed saccades exists in frontal cortical areas. 2. Determine if there are topographic maps in higher cortical areas of remembered target angle for auditory targets. 3. Determine if there are topographic maps in higher cortical areas of remembered target angle when a joystick is moved toward visual and auditory cues. Brain activity will be measured using functional magnetic resonance imaging. Subjects will be presented with visual cues via a mirror reflection of a projected image. Auditory cues will be presented through headphones with proper interaural differences in timing, sound level, and spectral composition, in order to simulate sounds originating in three dimensional space. After a delay period, subjects will make a saccade or joystick movement toward the remembered location of the stimulus. Brain activity correlated with stimulus location will be used to identify those higher cortical regions that display topographic maps of unimodal or multimodal sensory space. This project is an investigation into the neurobiological basis for memory of and attention to spatial location. ? ?
| Hagler Jr, D J; Riecke, L; Sereno, M I (2007) Parietal and superior frontal visuospatial maps activated by pointing and saccades. Neuroimage 35:1562-77 |
| Hagler Jr, Donald J; Saygin, Ayse Pinar; Sereno, Martin I (2006) Smoothing and cluster thresholding for cortical surface-based group analysis of fMRI data. Neuroimage 33:1093-103 |
