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

Mark Laubach laubach at
Mon Dec 18 20:10:07 EST 1995

jan at (Jan Vorbrueggen) wrote:

>In article <4aa6o2$efd at> laubach at (Mark
>Laubach) writes:

>   I want to point again that correlational analysis can not directly address
>   the issue of neural coding.  That is, if one is to conclude that a pattern
>   of spike activity is a putative code for some neural process related to
>   stimulus or behavior, then one must show that the pattern of activity is
>   _predictive_ of the stimulus or behavior.

>Hmm. The way I interpret this is: if the cross-correlation (or any other
>signal processing of the neuronal signals) of two neurons alllows you to
>distinguish stimuli that an old-fashioned PSTH does not, that
>cross-correlation (or whatever) contains information the PSTH has
>removed. Now, whether you can pinpoint the exact (statistical?) property of
>the signals that contains that information is quite another matter.

When are you going to distinguish the stimuli?  After looking at all
the trials on average?  My point was that we need trial-by-trial
predictors for analyzing neuron activity.  A cross-correlation is
nothing more than a correlational measure between time-series and a
correlational measure is not a predictor for trial-by-trial

>   Finally, I think that recent developments for large-scale parallel
>   recording (pioneered by our lab)

>Would Krueger (Freiburg) and Eckhorn (Marburg) agree with you?

Probably they would.  

When I said that the lab I work in pioneered the development of
methods for many neuron recording, I did not mean that we were the
only ones doing it.  The groups you mention deserve a lot of credit
for also working in this area.

At the same time, everybody out there who now uses a "Harvey" box from
Spectrum owes a good deal to the folks in our group who put a lot of
time and sweat into getting the whole thing off the ground.  Now, one
can record from 100s of cells simultaneously in behaving subjects,
including primates.  Can't wait till my post-doc!

Mark Laubach

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