Malformation of the Functional Organization of Somatosensory Cortex in Adult Ephrin-A5 Knock-Out Mice Revealed byIn VivoFunctional Imaging

• DOI: 10.1523/jneurosci.20-15-05841.2000
• Publication Date: 2018-04-06T20:45:39Z
• Authors: Neal Prakash; Pierre Vanderhaeghen; Susana Cohen-Cory; Jonas Frisén; John G. Flanagan; Ron D. Frostig
• Keywords: 0301 basic medicine; Optics and Photonics; Knockout; Inbred C57BL; Mice; 03 medical and health sciences; Thalamus; Neural Pathways; Thalamus -- cytology; Animals; Brain Mapping -- methods; Thalamus -- physiopathology; Somatosensory Cortex -- physiopathology; Mice, Knockout; Axons -- physiology; Brain Mapping; Membrane Proteins -- genetics; Age Factors; Membrane Proteins; Vibrissae -- innervation; Somatosensory Cortex; Sciences bio-médicales et agricoles; Ephrin-A5; Axons; Mice, Inbred C57BL; Somatosensory Cortex -- abnormalities; Vibrissae; Somatosensory Cortex -- cytology

The molecular mechanisms that coordinate the functional organization of the mammalian neocortex are largely unknown. We tested the involvement of a putative guidance label, ephrin-A5, in the functional organization of the somatosensory cortex by quantifying the functional representations of individual whiskersin vivoin adult ephrin-A5 knock-out mice, using intrinsic signal optical imaging. In wild-type mice ephrin-A5 is expressed in a gradient in the somatosensory cortex during development. In adult ephrin-A5 knock-out mice, we found a spatial gradient of change in the amount of cortical territory shared by individual whisker functional representations across the somatosensory cortex, as well as a gradient of change in the distance between the functional representations. Both gradients of change were in correspondence with the developmental expression gradient of ephrin-A5 in wild-type mice. These changes involved malformations of the cortical spacing of the thalamocortical components, without concurrent malformations of the intracortical components of individual whisker functional representations. Overall, these results suggest that a developmental guidance label, such as ephrin-A5, is involved in establishing certain spatial relationships of the functional organization of the adult neocortex, and they underscore the advantage of investigating gene manipulation usingin vivofunctional imaging.