neural coding of behavior: evidence for precise timing of spikes?

Mark Laubach laubach at biogfx.neuro.wfu.edu
Sat Dec 9 17:53:49 EST 1995


kate at anatomy.ucl.ac.uk (Kate Jeffery) wrote:

>John O'Keefe's group have shown that hippocampal place cells fire with a 
>very strict temporal relationship to the ongoing theta EEG rhythm in 
>behaving animals. Specifically, a cell will advance its firing with 
>respect to the theta phase as the animal runs through its place field, 
>always starting at the same theta phase. Thus, by knowing not just 
>*that* the cell was firing but also *when* it was firing with respect to 
>theta, it is possible to reconstruct the location of the animal much 
>more accurately. They have proposed a phase coding model of how an animal 
>might use this for navigation - I can supply some refs if you want.

Kate, thanks for the info.  I have a few questions.  How _precise_ is
this relationship?  That is, are spikes "locked" to theta on the order
of milliseconds or tens of milliseconds?

While such data clearly show that knowing the relationship between
theta and spikes is "good for something", i.e., predicting the
location of the subject, what is known about how such relationships
hold in relation to the performance of an operant task?  For example,
what about theta and delayed match(or non-match)-to-sample
performance?  By performance, I mean _trial-by-trial_ variation in
correctly pressing the target lever.


I guess I need to be more specific.  I am interested in whether there
is evidence for precise spike timing being important for the
performance of operant tasks.  

Precise timing: "Is there evidence for near-millisecond precision in
the timing of spike activity (interspike intervals) either within the
spike train of an individual cell or between cells in a neural
ensemble?"  

Operant performance: "Is there evidence for a covariation between the
occurrence of temporally precise interspike intervals and the
occurrence of errant behavior?"  
-----------------------------------
Mark Laubach
Dept. of Physiology & Pharmacology
Bowman Gray School of Medicine
Wake Forest University
Winston-Salem, NC 27157
laubach at biogfx.neuro.wfu.edu
-----------------------------------




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