current sinks and sources in hippocampal neurons (correction)

[Venkatesh Murthy]

In article <1le311INNbjg at shelley.u.washington.edu> venk at stein.u.washington.edu (Venkatesh Murthy) writes:

[.......]

>The EPSP is usually due to synaptic currents flowing INTO the dendrites - in 
>other words, the sink is more distal to the soma (and your recording
>electrode in the cell body layer.  So at the location you are recording
         ^^^^^^^^^^^^^^^^^^^^^^^^
           is in the cell body layer).

>from there is in effect a source.  When the population spike occurs,
>presumably many of the cells are spiking.  This causes a great big sink
>to occur near/at the some since by far most of the action potential
                      ^^^^
                      soma

>currents are dominant at the soma (if not by density of channels, by 
>sheer number).  So, your recording electrode is seeing a sink and it 
>records a "negative" potential.  
>
>Can someone else confirm or refute this?  Bill Calvin, maybe?
>

Sorry for the typos!

-Venki Murthy
Physiology & Biophysics, SJ-40
University of Washington
Seattle, WA 98195
(venk at u.washington.edu)