As a microelectrode advances tangentially (parallel to the surface) through the cortex in a single layer, what occurs to the preferred orientation of hte neurons?
As a microelectrode advances tangentially (parallel to the surface) through the cortex in a single layer, the preferred orientation progressively shifts. We now know, from the use of a technique called optical imaging, that there is a mosaiclike pattern of optimal orientations in striate cortex. If an electrode is passed at certain angles through this mosaic, the preferred orientation rotates like the sweep of the minute hand of a clock, from the top of the hour to ten past to twenty past, and so on. I fthe elctrode is moved at other angles, more sudden shifts in preffered orientation occur. Hubel and Wiesel found that a complete 180 degree shift in preferred orientation required a traverse of about 1 mm, on average, within layer III