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What's a Brain Wave?

F. Frank LeFever flefever at ix.netcom.com
Tue Apr 20 20:54:36 EST 1999

Yes, yes, yes, of course--but HOW???

What is the cellular mechanism for doing this?  Surely it cannot be so
simple as "the neurons get tired without sufficient oxygen and don't
fire so often", considering that we have a co-ordinated firing,
emerging as a slow rhythm.

In a previous post, Matt Jones pointed out how temporal characteristics
of GABA discharges and duration of receptor activities coincided nicely
with frequency of hippocampal theta--although quick to point out that
this was not necessarily the cause of the rhythm.

In the case of various other theta phenomena, what is known about
cellular mechanisms producing this prominent slowing?

Ass regards source: given more prominent theta frontally, does this
mean that the rhythm arises from some specific alteration of activity
in frontal tissue itself (if so, what is the cellular mechanism?), or
does it meean that neurons in this region are driven by (e.g.) inputs
from the brainstem (e.g. A-10? A-9? I forget. or loc. coeruleus?
raphe?) which are responding to altered blood gasses?

F. LeFever

In <7fhi52$kb8$1 at oravannahka.Helsinki.FI>
dag.stenberg at helsinki.nospam.fi writes: 
>F. Frank LeFever <flefever at ix.netcom.com> wrote:
>> I understand that something so simple as hyperventilation can
>> theta, concurrently with diminished cognitive ability--but HOW?
>During hyperventilation, CO2 is eliminated from the body, resulting in
>vasoconstriction and redistribution of blood flow also in the brain
>the periphery, one notices that hands and feet get cold and start to
>The resulting hypoxia in brain tissue is accompanied by theta and even
>delta waves in the EEG, especially noticeable in frontal areas.
>Dag Stenberg
>Dag Stenberg     MD PhD                    stenberg at cc.helsinki.fi
>Institute of Biomedicine		   tel: (int.+)358-9-1918532
>Department of Physiology                   fax: (int.+)358-9-1918681
>P.O.Box 9        (Siltavuorenpenger 20 J)   
>FIN-00014 University of Helsinki,Finland   

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