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Biomedical subjects

E Gary-Bobo

Publications and source records attributed to E Gary-Bobo.

25 records · Page 2Linked to original sources
PubMed1979

Development of visual cortical orientation specificity after dark-rearing: role of extraocular proprioception.

Six-week-old dark reared kittens exposed to light for 6 h: (1) with head and body tightly cast into plaster; or (2) free to move around in the animal room. A few days before the visual experience, the ophthalmic branch of the 5th nerve was severed bilaterally in experimental kittens, in order to suppress most of the proprioceptive afferents from extraocular muscles. Electrophysiological analysis of the properties of the receptive fields of visual cortical cells shows that only 6% (group 1) and 11% (group 2) of the cells were selective to orientation as opposed to 67% (group 1) or 32% (group 2) observed in the non-operated kittens.

Animals↗
PubMed1978

[Persistence of orientation-selective cells of the primary visual cortex in kittens enucleated unilaterally at birth and reared in darkness].

In kittens dark reared (6 weeks old) orientation selective cells are no longer recorded in the primary visual cortex, while in kittens of same age, enucleated at birth unilaterally and reared in identical conditions, 30% of visual cortical cells are shown to be orientation selective and in addition respond preferentially to horizontal and vertical orientations.

Animals↗
PubMed1977

[Stabilization of operant responses during a program of variable interval reinforcement as a preliminary investigation of sensory thresholds using conditioned suppression in the cat].

Cats were trained to press a key during a variable interval schedule of reinforcement with a limited hold contingency. The main modifications of the response rate were observed when the subject missed one reinforcement or obtained more than one reinforcement during the limited hold. The existence of a zone of lesser variability in the mean response rate is shown to be linked to the occurrence of the last reinforcement. This result suggests an original methodological contingency concerning the use of conditioned suppression in psychophysics. The schedule of sensory stimulation should be established for each subject during that period of lesser variability between two reinforcements.

Animals↗
PubMed1977

Commissural projection to the amygdala thourgh the fimbria fornix system in the cat.

Single shock stimulations have been applied stereotaxically and bilaterally in the region of the caudo-thalamic groove of the cat. These stimulations elicit diphasic potentials in the amygdala. Using combined methods of stimulation and lesion, it has been demonstrated that these electrical responses are due to the excitation of fibers projecting rostrally in the lateral border of the contralateral fimbria and caudally in the homologous part of the homolateral fimbria. A commissural path has been identified in the rostral part of the fimbria-fornix. Analysis of the experimental data has shown that the projection system consists of a discrete bundle of fibers which probably reaches the amygdala directly, in the dorsal part of the basal nucleus. The length of the explored portion of this pathway has been measured. The calculated conduction velocity of this amygdalopetal commissural component of the fimbria is 4.5 m/sec.

Amygdala↗