Biomedical subjects

J A Gengerelli

Publications and source records attributed to J A Gengerelli.

11 recordsLinked to original sources

PubMed1986

Influence of a 14-day regimen of electrical stimulation involving large portions of the cerebral mass on later habit acquisition in the rat.

Four groups of rats, one of which served as a normal, nonoperated group, were used. The other three groups were operated and fitted with an electrode carrier of eight electrodes of varying lengths arranged in a 7.5 mm X 5 mm rectangle. About 10 or 12 days after surgery, the following groups of animals underwent a 14-day regimen wherein each animal spent 15 min in a deep, metal, electrically insulated cylinder: Group A, normal, nonoperated group, with no intervention; Group B, stimulated each day with 45 trains of rectangular biphasic pulses (3 trains per min) at the rate of 20 pulses per second (pps); Group C, the same but at the rate of 100 pps; Group D, the same but 180 pps. After a 48-hr fast and without benefit of shaping, each animal was placed for 60 min in a lever-pressing device and was rewarded with a pellet after each three to four presses. The resulting performance curves showed no improvement in pressing rate for Group A; marginal improvement for Group B; definite improvement for Group C; and the greatest improvement for Group D, the terminal rate being almost twice that of Group C.

Animals↗

PubMed1979

Termination locus of palmar main line A of the left hand in relation to mental pathology.

A ridge originating at digital triradius point a (palmar main line A) was measured from photographs in three groups of Ss, each composed of 36 males: 1) chronic, hospitalized schizophrenics; 2) chronic, hospitalized patients classified as nonpsychotic; 3) business and professional men who were members of a service club. Seven naive judges measured the point of exit of main line A at the ulnar edge of the left palm in each of the 108 SS. Results were as follows: (a) Range of scores in units used was 5.00 to 7.75; total variance, .26 (N = 756). (b) Means of the two control groups were identical, but schizophrenic and control group difference failed to meet the .05 level of significance. (c) Very significant differences were found among judges' means. (d) Median interjudge r = about + .69.

Dermatoglyphics↗

PubMed1978

Wave coherence in the human EEG.

The investigation is concerned with the phase coherence of human EEG's taken from the median plane of the scalp (N = about 125 male and female undergraduates). Manifestation of coherence was made by using scalp potentials of not less than a fixed value to trigger the sweep of a computer of average transients. Very coherent phase relationships were observed in the occipital region in the form of waves having a period of about 100 msec under a condition of bodily and mental relaxation and eyes closed. With eyes open and under a condition of motivated visual perception, wave coherence disappeared in nearly all S s. Coherence in the alpha frequency diminished as derivation moved toward the frontal region. In some S s, coherence was also noted for waves with a period of 55-60 msec, derived from the occipital region under condition of relaxation. In many individuals, coherent waves of this period were derived from the parietal, central, and frontal areas.

Action Potentials↗

PubMed1976

Eidetic imagery in two subjects after 46 years.

Two quantitative experiments involving eidetic imagery, performed in 1928-29 on two girls, ages 11 and 15 years, respectively, were repeated in every detail in 1974 on the same two persons. It was found that minor changes (perhaps unreliable) had occurred in the precision of eidetic projection, and that both Ss retained their ability to project a seen circle onto a target square and compare the two for "goodness of fit."

Adolescent↗

PubMed1976

Studies in the neurophysiology of learning: X. Phase coherence of brain potentials as index of alertness and orienting response in the rat.

With use of electrical potentials derived from chronically implanted electrodes in the rat's forebrain to trigger a computer of average transients (CAT), averaged traces were obtained which gave characteristic undulations under conditions of arousal and alertness (N = seven albino rats--six male and one female). Under conditions of extreme adaptation to the environmental condition, the averaged undulations disappeared. The undulations were characterized by a period of 125-150 milliseconds and occurred in trains of .3-.5 second. The parameters of the waves were constant for a variety of novel environmental conditions, but the waves vanished in those conditions that appeared to greatly stress or terrify the rat. The undulations so obtained were conditionable to initially neutral stimuli in both the forward and backward directions.

Animals↗

PubMed1975

Studies in the neurophysiology of learning: IX. Conditioning of evoked potentials due to cerebral stimulation.

The hypothesis to be tested was that if characteristic undulatory evoked potentials could be produced by electrical stimulation of the lateral hypothalamus, sensory stimuli originally neutral should evoke such potentials, if only of smaller amplitude. The results of experiments on four albino rats are reported. Stimulation of the lateral hypothalamus by electrical current at 200 biphasic rectangular pulses per second results in 7-12 cycles-per-second undulations persisting for about .5 second and derivable from several regions of the cerbrum. By means of the Pavlovian paradigm, it was possible to condition these to an auditory and to a visual stimulus. The conditioned undulations had smaller amplitudes, did not persist as long to CS as to US, and were characterized by considerable lability. From 100 to 300 CS-US pairings were required.

Animals↗

PubMed1973