Visual field maps, population receptive field sizes, and visual field coverage in the human MT+ complex

J Neurophysiol. 2009 Nov;102(5):2704-18. doi: 10.1152/jn.00102.2009. Epub 2009 Jul 8.

Abstract

Human neuroimaging experiments typically localize motion-selective cortex (MT+) by contrasting responses to stationary and moving stimuli. It has long been suspected that MT+, located on the lateral surface at the temporal-occipital (TO) boundary, contains several distinct visual field maps, although only one coarse map has been measured. Using a novel functional MRI model-based method we identified two maps-TO-1 and TO-2-and measured population receptive field (pRF) sizes within these maps. The angular representation of the first map, TO-1, has a lower vertical meridian on its posterior side at the boundary with the lateral-occipital cortex (i.e., the LO-2 portion). The angular representation continues through horizontal to the upper vertical meridian at the boundary with the second map, TO-2. The TO-2 angle map reverses from upper to lower visual field at increasingly anterior positions. The TO maps share a parallel eccentricity map in which center-to-periphery is represented in the ventral-to-dorsal direction; both maps have an expanded foveal representation. There is a progressive increase in the pRF size from V1/2/3 to LO-1/2 and TO-1/2, with the largest pRF sizes in TO-2. Further, within each map the pRF size increases as a function of eccentricity. The visual field coverage of both maps extends into the ipsilateral visual field, with larger sensitivity to peripheral ipsilateral stimuli in TO-2 than that in TO-1. The TO maps provide a functional segmentation of human motion-sensitive cortex that enables a more complete characterization of processing in human motion-selective cortex.

Publication types

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

MeSH terms

  • Brain Mapping*
  • Functional Laterality / physiology
  • Humans
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Imaging / methods
  • Motion Perception / physiology*
  • Occipital Lobe / blood supply
  • Occipital Lobe / physiology*
  • Oxygen / blood
  • Pattern Recognition, Visual / physiology
  • Photic Stimulation
  • Psychophysics
  • Visual Fields / physiology*
  • Visual Pathways / blood supply
  • Visual Pathways / physiology

Substances

  • Oxygen