16
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Magnocellular and parvocellular visual pathways have different blood oxygen level-dependent signal time courses in human primary visual cortex.

      AJNR. American journal of neuroradiology
      Brain Mapping, Contrast Sensitivity, physiology, Echo-Planar Imaging, Energy Metabolism, Evoked Potentials, Visual, Geniculate Bodies, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Mathematical Computing, Neurons, Oxygen, blood, Pattern Recognition, Visual, Retina, Retinal Ganglion Cells, Software, Synaptic Transmission, Visual Cortex, Visual Pathways

      Read this article at

      ScienceOpenPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The magnocellular and parvocellular pathways (M and P pathways) are the major pathways of the visual system, with distinct histologic and physiologic properties that may also have different metabolic characteristics. We hypothesize that the differences of the 2 visual pathways would also manifest as differences in the signal time course of blood oxygen level-dependent functional MR imaging (BOLD fMRI). The differences in BOLD signal time course may provide insight into the metabolic requirements of the 2 pathways. Eleven fMRI sessions on 6 subjects were performed using stimuli that preferentially activated the 2 pathways. Regions commonly activated by both the M and P stimuli in the primary visual cortex (V1) were determined, and the contrast elicited by the stimulus, time-to-peak (TTP), and the full width at half maximum (FWHM) of the BOLD signal time course were measured. The functional stimuli activated cortical regions described previously in the literature, such as V1, V4, and V5. Within V1, the TTP of the signal time course of the 2 stimuli were statistically different, with the P stimulus generating TTPs that were on average 12% faster than the M stimulus (P = .0037). We have demonstrated the ability to functionally differentiate the M and P stimuli in a commonly activated anatomic region. Because the BOLD response is dependent on the ratio of oxyhemoglobin and deoxyhemoglobin in the blood, the difference in the BOLD time course between the 2 stimuli suggests that the oxygen demand of the 2 pathways may be different.

          Related collections

          Author and article information

          Comments

          Comment on this article