73370.2242 at CompuServe.COM
Tue Sep 10 09:51:08 EST 1996
>The apical dendrites of cortical pyramidal cells are aligned
>perpendicular to the cortical surface -- this allows the PSPs in
>the apical dendrites of many (millions?) cortical pyramidal
>cells to summate spatially, and thus be detectable on the
>cortical or scalp surface. The dendrites of other cell types
>are generally aligned in random directions, so that the PSPs in
>these dendrites cancel each other (when observed from an
>electrode that is "far" away).
Kevin, thanks for replying to my post and to the one above.
Since the brain has many folds & invaginations, many of the
apical dendrites would not be at right angles to the surface of
the brain. Why isn't this a problem in assuming the valididty of
EEG recordings ? Would local field potentials recorded from one
laminellar layer be a more suitable means for determining the
activity of a brain area and perhaps for investigating the
relationship between say, midbrain structures and the cortex ?
Thanks for your attention.
More information about the Neur-sci