Topographic organization of macaque area LIP

Proc Natl Acad Sci U S A. 2010 Mar 9;107(10):4728-33. doi: 10.1073/pnas.0908092107. Epub 2010 Feb 19.

Abstract

Despite several attempts to define retinotopic maps in the macaque lateral intraparietal area (LIP) using histological, electrophysiological, and neuroimaging methods, the degree to which this area is topographically organized remains controversial. We recorded blood oxygenation level-dependent signals with functional MRI from two macaques performing a difficult visual search task on stimuli presented at the fovea or in the periphery of the visual field. The results revealed the presence of a single topographic representation of the contralateral hemifield in the ventral subdivision of the LIP (LIPv) in both hemispheres of both monkeys. Also, a foveal representation was localized in rostral LIPv rather than in dorsal LIP (LIPd) as previous experiments had suggested. Finally, both LIPd and LIPv responded only to contralateral stimuli. In contrast, human studies have reported multiple topographic maps in intraparietal cortex and robust responses to ipsilateral stimuli. These blood oxygenation level-dependent functional MRI results provide clear evidence for the topographic organization of macaque LIP that complements the results of previous electrophysiology studies, and also reveal some unexpected characteristics of this organization that have eluded these previous studies. The results also delineate organizational differences between LIPv and LIPd, providing support for these two histologically defined areas may subserve different visuospatial functions. Finally, these findings point to potential evolutionary differences in functional organization with human posterior parietal cortex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Brain Mapping
  • Fovea Centralis / anatomy & histology
  • Fovea Centralis / innervation
  • Fovea Centralis / physiology*
  • Functional Laterality / physiology
  • Humans
  • Macaca mulatta / anatomy & histology
  • Macaca mulatta / physiology*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Parietal Lobe / anatomy & histology
  • Parietal Lobe / physiology*
  • Psychomotor Performance / physiology
  • Space Perception / physiology
  • Visual Perception / physiology