At 12:14 AM 09/15/2000 -0500, jim clark wrote:
>Hi
>
>On Thu, 14 Sep 2000, Nathalie Cote wrote:
> > So is there an auditory chiasm and do the visual field tests done with
> split
> > brain patients work similarly with the left and right auditory fields?
>
>The visual tests can be done because the left half of each eye
>(right visual field) goes to the right hemisphere and the right
>half of each eye (left visual field) goes to the left hemisphere.
>(I might have this reversed... I always found it quite confusing)
Right visual field goes to left hemisphere and left visual filed goes to
right hemisphere. This can be used with normals and is called a divided
visual field paradigm. so the visual information must be flashed VERY
quickly (under 200 ms) right or left of the central fixation marker,
because the information rapidly crosses the corpus callosum.
Dawn
>Thus researchers can control which hemisphere receives the
>stimulus by placing the stimulus in either the left or right
>visual field. Similarly, I gather that tactual perception is
>completely crossed (i.e., right hand projects to left hemisphere
>and vice versa) given split-brain studies in which patients grasp
>objects with either the left or right hand.
>
>Audition, however, is not completely crossed. There are
>projections from each ear to both hemispheres, but with the
>contralateral connection stronger, perhaps especially
>(only?) when both ears receive competing messages. I suspect
>that controlled auditory presentation to one hemisphere would be
>more difficult to achieve than in vision or touch.
>
>Best wishes
>Jim
>
>============================================================================
>James M. Clark (204) 786-9757
>Department of Psychology (204) 774-4134 Fax
>University of Winnipeg 4L05D
>Winnipeg, Manitoba R3B 2E9 [EMAIL PROTECTED]
>CANADA http://www.uwinnipeg.ca/~clark
>============================================================================
Dawn G. Blasko Ph.D.
Associate Professor of Experimental Psychology
Penn State Erie, The Behrend College
Station Road
Erie, PA 16563-1501
Office phone: 814-898-6081
http://www.pserie.psu.edu/hss/psych/blasko.htm
