Ottó Fehér

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In associative learning, the activated neurones undergo a variety of concomitant functional alterations--increases or decreases of firing activity and modifications of membrane potential or resistance and of synaptic responsiveness. Synaptic transmission which can be strengthened only when there is paired activity in two pathways is of particular interest(More)
Monocular (ME) and binocular enucleation has become a useful experimental tool for analyzing the mechanisms of neural plasticity. ME when performed during an early postnatal period (up to 15 days after birth) initiates a series of adaptive reactions in the visual (and other sensory) system(s) which tend to compensate for the lost sensory capacity.(More)
The cortices of neonatally enucleated rats were explored for somatosensory responses with special reference to an extension into the occipital cortex. Monocular enucleation was performed on rats at birth. The animals were raised and from the age of three months the activity evoked by either electric stimulation of the vibrissa pad or bending of the(More)
Intracellular recordings were made from 117 neurons in the motor cortex of anesthetized cats. The pyramidal tract (PT) and VL nucleus of thalamus were stimulated in order to activate the neurons from two directions. 1. PT cells were conditioned by antidromic trains (10–50 cps for 4–15 s) and by paired PT and VL stimuli with different intervals and(More)
Aggressive T-cell neoplasms are an infrequent complication of allogeneic organ and bone marrow transplantation. To date, chronic T-cell lymphoproliferative malignancies have not been described. The present case documents the occurrence of a T-cell large granular lymphocytic leukemia (T-LGL) in a patient following orthotopic liver transplantation. Genotype(More)
Monocular enucleation was performed on rats at birth or on the 8th or 15th day, respectively. The animals were raised and from the age of 3 months the evoked activity was tested in the visual cortex. It was found that monocular enucleation changed the distribution of visually evoked responses. In the right hemisphere (contralateral to the preserved eye) two(More)
Interactions of acoustic and somatosensory evoked potentials were studied in the anterior suprasylvian gyrus of the cat. Two kinds of interaction could be observed: occlusion or facilitation. In most cases occlusion was observed. The interactions showed dynamic changes and were susceptible to different kinds of influences. After having determined the(More)
The effects of Pentylenetetrazol (PTZ) on the metacerebral giant cell (MCC) of the snail, Helix pomatia were studied. Actions on membrane resistance, time constant, resting and action potentials, outward and inward ionic currents were examined. Superfusion with PTZ in concentrations of 25 to 50 mmol/l, induced a gradually evolving convulsive state, which(More)
The superior cervical ganglion (SCG) of adult rats was exposed to GABA, either by long lasting microapplication (implantation of glass bulbs for 1-24 days) or in short term experiments (external application up to 6 h). Autoradiography showed that [3H] GABA accumulated selectively in satellite cells. The GABA produced the following effects: (1) Specialized(More)