Affiliations: Cognitive Neuroscience Research Unit, University of
Durham, Durham, UK | Clinical Neuroscience Centre, University of Hull,
Hull, UK | Department of Neuroscience, University of Sheffield
and Sheffield Teaching Hospital, Sheffield, UK and San Camillo Hospital,
Venice, Italy
Note: [] Address for correspondence: Dr. Igor Schindler, Clinical
Neuroscience Centre, Department of Psychology, University of Hull, Cottingham
Road, Hull, HU6 7RX, UK. Tel.: +44 1482 465563; Fax: +44 1482 465599; E-mail:
[email protected]
Abstract: INTRODUCTION: Patients with unilateral neglect may show line
bisection errors selectively in either near (within hand reaching) or far
(beyond hand reaching) space which suggests that these two spatial areas are
coded differently by the brain. This exploratory study investigated, whether
any difference in performance between these spatial domains might be
task-independent or modulated by the requirement for a motor response. METHODS: A 31-year-old right brain damaged patient (MF) and a group
of age matched healthy controls were assessed with two serial visual search
tasks and a Landmark paradigm. Both types of task required either a directional
(pointing) or non-directional (button press) motor response. Participants were
assessed with both task types and response modes in near (57 cm) and far space
(114 cm). RESULTS: MF showed left neglect during visual search only in far
space for the perceptual condition and in near space for the motor condition.
MF showed no neglect in both versions of the Landmark task irrespective of
spatial distance. A voxel-based morphometric assessment of MF's brain lesion
showed marked damage in the right ventro-temporal cortex, superior temporal
gyrus, insula, inferior frontal gyrus, angular gyrus and bilaterally in the
posterior cingulate cortex. CONCLUSIONS: Our preliminary findings suggest that processing of far
space during visual search is associated with ventral stream damage but only
when space is coded through visual information. Neglect involving directional
motor activity in near space seems to be associated with damage of structures
sharing close connections with the dorsal stream.
Keywords: Spatial neglect, distance, line bisection, visual search, MRI, VBM
