40-Hz oscillations

Steven M. Boker smb3u at delton.psyc.virginia.edu
Tue Jun 1 11:47:50 EST 1993


In article <1993Jun1.131324.23523 at ucl.ac.uk> charles at anat.ucl.ac.uk writes:
>Anyone interested in 40Hz oscillations should take a look at 'Cortical oscillations
>and temporal interactions in a computer simulation of piriform cortex' by M Wilson
>and J Bower J Neuroscience 67:981-995, 1992. 
>
>They put forward the idea that the oscillations are simply caused by the delay-line effects of intra-cortical connections. I must say I am dubious about the importance 
>of any oscillations which depend critically on delay-lines (ie dependent on axonal
>lengths and conduction velocities) as such a set-up doesn't strike me as being very
>robust. More interesting are the slower, 5-10Hz oscillations dependent on channel time
>constants (GABAb, T-type Ca current, Iq).
>

I would have to agree that the delay line hypothesis is insufficient
to explain phase-locking of the 44Hz oscillations over large areas
of cortex.  More likely is the spiny stellate inhibitory interneuron
observed by Llinas et.al which has a narrow oscillatory rebound in
the 40Hz range.  The article is:

@ARTICLE{Llinas91a,
	AUTHOR = {Llin\'{a}s, R. and Grace, A. A. and Yarom, Y.},
	TITLE = {In vitro neurons in mammalian cortical layer 4 exhibit intrinsic oscillatory activity in the 10-- to 50--{H}z frequency range},
	JOURNAL = {Proceedings of the National Academy of Sciences of the United States of America},
	VOLUME = {88},
	PAGES = {897--901},
	YEAR = {1991}
}

Steve 


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 #  Steven M. Boker            #       "Two's bifurcation         #
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