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C J Sherry

Publications and source records attributed to C J Sherry.

At least 37 records · Page 2Linked to original sources
PubMed1981

Entropy as an index of the informational state of neurons.

Techniques were developed for using the classical information theory descriptor, entropy, to quantify the "uncertainty" present in neuronal spike trains. Entropy was calculated on the basis of a method that describes the relative relationships of serially ordered interspike intervals by encoding the intervals as a series of symbols, each of which depicts the relative duration of two adjacent spike intervals. Each symbol, or set of symbols has a specific fractional entropy value, derived from its probability of occurrence; moreover, fractional entropy can describe the relative amount of "information" that is associated with the relative location of a given symbol in a string of symbols. Using spike trains from 12 single neurons in the cerebellar cortex of rats, we determined: (1) the mean and S.D. of information content of each symbol in each specific position in a group of symbols (2-4 symbols/group, based on 3-5 adjacent intervals), (2) the 4-symbol groups which had the least and the most average fractional entropy, (3) that the 4-symbol groups with both low and high fractional entropy had significant positive correlations with the probability of occurrence of those groups after a drug treatment (ethanol), and (4) that the degree of drug-induced change in the incidence of both low- and high-fractional entropy groups did not correlate with predrug entropy. Thus, the entropy of clusters of 3-5 adjacent spike intervals, when computed in this particular way, seems to be a useful measure or index of the informational state of neurons.

Action Potentials↗
PubMed1980

Tongue manipulation of the palate assists estrous detection in the bovine.

To understand the mechanisms for introducing urine or vaginal secretions into the vomeronasal organ, we used 16 mm cinematography and a freeze frame/slow motion technique to analyze the mouth and tongue movements of Brahman bulls while they examined the vulvas of restrained, estrogen-primed cows. Prior to flehmen, the mouth slowly opened, the curled tip of the tongue compressed the hard palate and the body of the tongue protruded from the mouth. The tongue maintained this form and moved forward. Once the tip of the tongue reached the incisive papilla, the body of the tongue retracted and the tip of the tongue relaxed. This tongue compression stroke (TCS) of the hard palate occurred 2 to 6 times, lasting 1 4 to 1 2 sec/stroke. Pressure changes in the vomeronasal organ are assumed to occur during and following TCSs, resulting in aspiration of any liquid in the incisive pit into the incisive and vomeronasal ducts. Such aspiration probably does not occur during flehmen because the tongue is relaxed and on the floor of the mouth.

Journal Article↗
PubMed1980

The statistical relationship between the "entropy" of a neuronal signal and its variability.

We used a serial order nonparametric analysis technique to analyze trains of neuronal action potential intervals in terms of classical information theory. We observed a marked correlation between the information theory descriptor, entropy, and several common measures of variability (median interval length, range of interval length, and skewness of the probability density function). The correlation between variability and entropy was accounted for in the following decreasing order: range of intervals, median interval, and skewness. These data suggest a significant relationship between the signal and its variability and entropy, when entropy is calculated by our serial-order pattern detection method.

Action Potentials↗