E-function

2013-02-28T10:55:51Z

92.28.8.74: /* Uses */ Improved vastly

In [[neurophysiology]], '''peristimulus time histogram''' and '''poststimulus time histogram''', both abbreviated '''PSTH''' or '''PST histogram''', are [[histogram]]s of the times at which neurons fire. These histograms are used to visualize the rate and timing of neuronal spike discharges in relation to an external stimulus or event. The peristimulus time histogram is sometimes called '''perievent time histogram''', and ''post-stimulus'' and ''peri-stimulus'' are often [[hyphen]]ated.

The prefix ''peri,'' for ''through,'' is typically used in the case of periodic stimuli, in which case the PSTH show neuron firing times wrapped to one cycle of the stimulus. The prefix ''post'' is used when the PSTH shows the timing of neuron firings in response to a stimulus event or onset.<ref>{{cite book | title = Introduction to Electrophysiological Methods and Instrumentation | author = Franklin Bretschneider and Jan R. De Weille | url = http://books.google.com/?id=2ybw9UoRVBUC&pg=PA188&dq=peri-stimulus-time-histogram+post-stimulus-time-histogram | publisher = Academic Press | isbn = 0-12-370588-6 | year = 2006 }}</ref>

To make a PSTH, a spike train recorded from a single neuron is aligned with the onset, or a fixed phase point, of an identical stimulus repeatedly presented to an animal. The aligned sequences are superimposed in time, and then used to construct a histogram.<ref>{{cite journal
| last =Palm
| first =G.
| authorlink =
| coauthors =Aertsen, A. M.; Gerstein, G. L.
| title =On the significance of correlations among neuronal spike trains
| journal =Biological Cybernetics
| volume =59
| issue =1
| pages =1–11
| publisher =
| date =1988
| doi =10.1007/BF00336885
| id =
| accessdate =
| pmid =3401513 }}
</ref>

== Construction procedure ==

# Align spike sequences with the onset of stimuli that repeated ''n'' times. For periodic stimuli, wrap the response sequence back to time zero after each time period ''T'', and count ''n'' as the total number of periods of data.
# Divide the stimulus period or observation period ''T'' into ''N'' bins of size <math>\Delta</math>.
# Count the number of spikes ''ki'' from all ''n'' sequences that fall in the bin ''i''.
# Draw a bar-graph histogram with the bar-height of bin ''i'' given by <math>\frac{k_i}{n \Delta}</math> in units of estimated spikes per second at time <math>i\ \Delta</math>.

The optimal bin size Δ is a minimizer of the formula, (2k-v)/Δ2,
where k and v are mean and variance of ki.
<ref>{{cite journal
| last = Shimazaki
| first =H.
| authorlink =
| coauthors =Shinomoto, S.
| title =A method for selecting the bin size of a time histogram
| journal = Neural Computation
| volume =19
| issue = 6
| pages =1503–152
| publisher =
| date =2007
| url = http://www.mitpressjournals.org/doi/abs/10.1162/neco.2007.19.6.1503
| doi = 10.1162/neco.2007.19.6.1503
| pmid = 17444758 }}
</ref>

== References ==

{{reflist}}

[[Category:Neurophysiology]]

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