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J Winson

Publications and source records attributed to J Winson.

6 recordsLinked to original sources
PubMed1978

Loss of hippocampal theta rhythm results in spatial memory deficit in the rat.

Rats learned, using distal room cues, to run to a goal on an elevated, circular track starting from any position on the track. The goal was one of eight equidistant, recessed cups set around the track, the goal cup being distinguished from the others solely by its position in the room. After learning, electrolytic lesions were made in the medial septal nucleus eliminating hippocampal theta rhythm in some animals but not in others. Rats without theta rhythm were no longer able to perform the spatial task, whereas rats with undisturbed theta rhythm retrained normal performance. Although rats without theta rhythm could not find their way directly to the goal, they recognized its location when they came upon it by chance. This type of spatial deficit appears similar to that shown by hippocampally lesioned patient H.M. Subsequent tests demonstrated that rats deprived of theta rhythm before training could nevertheless learn the task.

Animals↗
PubMed1978

Neuronal transmission through hippocampal pathways dependent on behavior.

1. In chronically prepared, freely moving rats, electrical stimulation was applied to the angular bundle, and responses were recorded extracellularly at a variety of sites in the ipsilateral hippocampal formation. At each recording site the stimulus-response relationship was tested during four different behavioral states. These were slow-wave sleep (SWS), REM sleep ( REM), and also two waking behaviors consisting of the still, alert condition (labeled SAL), and voluntary movement (AW theta). 2. Two varieties of evoked responses were recorded: those due to the synchronous firing of neuronal action potentials (EAPs) and those produced by excitatory synaptic activity (ESPs). The overall pattern of monosynaptic, di-, and trisynaptic responses found was similar in the rat to that found by Andersen et al. (3-5) in cat and rabbit. 3. When the trisynaptic EAP was recorded in CA1, the threshold was similar during all four behavioral states. However, suprathreshold stimuli evoked a greater response during SWS than during the other three states. The trisynaptic ESP was also greater during SWS. 4. Disynaptically, EAPs were recorded in CA3. These were greater in magnitude during SWS than during SAL, but were intermediate in mean amplitude during AWtheta and REM. Response variability was much greater during AWtheta and REM. 5. The monosynaptic EAP recorded in the upper blade of the dentate gyrus (DG) exhibited the same behaviorally correlated properties found disynaptically in CA3. 6. The monosynaptic ESP recorded in the DG, in contrast to the EAP, was greater in magnitude during SAL than during SWS. 7. The primary afferent volley was also recorded at high gain in the DG. The amplitude of this was found to be dependent solely on stimulus intensity and not on behavioral state. 8. The results are interpreted as suggesting that the granule cell membranes in the DG are relatively hyperpolarized during SAL compared with SWS as the result of either tonic excitatory bombardment occurring during SWS or tonic inhibitory bombardment during SAL.

Animals↗
PubMed1977

Gating of neuronal transmission in the hippocampus: efficacy of transmission varies with behavioral state.

Electrical stimuli were applied to the angular bundle of the freely moving rat, and the neuronal responses were recorded ipsilaterally in the dentate gyrus and the CA1 field of the hippocampus. The number of neurons responding monosynaptically in the dentate gyrus was relatively small when the animal was alert and not moving but was much greater both during slow-wave sleep and during rapid eye movement sleep. In Ca1, however, the trisynaptic population response was considerably smaller during rapid eye movement sleep and when the animal was alert than during slow-wave sleep. These findings are interpreted in terms of a set of behaviorally dependent "neural gates". Measurement of the synaptic current at the dentate gyrus induced monosynaptically by stimulation of the angular bundle further suggests that the mechanism by which gating occurs at this level is either a tonic inhibitory synaptic influence exerted upon the granule cells during the alert state, a tonic excitatory influence during slow-wave sleep, or both.

Action Potentials↗
PubMed1976

Hippocampal theta rhythm. II. Depth profiles in the freely moving rabbit.

Depth profiles of hippocampal theta rhythm were investigated in the freely moving rabbit during three behavioral conditions: REM sleep, voluntary movement, and during sensory stimulation applied to the motionless animal. Profiles were found to be the same in all three conditions. Dorsoventral microelectrode penetration of the dorsal hippocampus revealed an approximately uniform amplitude of theta rhythm in strata oriens and pyramidal of CA1. Further microelectrode advancement revealed a sharp reversal of phase and a coincident null in amplitude in the proximal stratum radiatum. There was also a peak of theta rhythm amplitude which occurred in the molecular layer of the dorsal blade of the dentate gyrus. These data imply that in the rabbit, as in the freely moving rat, there are two generators of theta rhythm in the dorsal hippocampus, one in the dentate gyrus and the other in the overlying CA1 layer. The data also indicate the existence of a species difference in generating systems between the rabbit and the rat.

Animals↗
PubMed1976

A simple sleep stage detector for the rat.

A simple sleep stage detector for the rat is described, which uses as its sources of input the signal from a single hippocampal recording electrode and the signal generated by a motion indicator. The device is suitable for use in sleep studies and in experiments on REM sleep deprivation.

Animals↗