A removable peripheral device for intracerebral microinjection in freely moving rats.

This report describes an original, removable, peripheral device: a microinjector that injects a single dose of fluid chemical into a particular site in the brain of freely moving rats. The microinjector was constructed especially for simultaneous use with a microdrive for microelectrode recording of single neuron activity but can be utilized alone. The microinjector is simple, lightweight, small, and easy to operate and maintain.

Participation of nucleus entopeduncularis in motor instrumental reflex and entopeduncular influences on motor thalamic nuclei in normal and MPTP-treated cats.

Activity of entopeduncular neurons was studied in chronic experiments on cats during performance of instrumental movement: pedal pressing and holding. One-hundred and twenty-four neurons were extracellularly investigated in intact animals and 81 neurons in cats treated with N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (5 mg/kg daily, intramuscularly for five days). The mean discharge frequency of nucleus entopeduncularis neurons recorded 48-72 h after the last MPTP injection increased from 12.

[The neuronal reactions of the parietal associative cortex (area 5) in the cat during internal inhibition of the instrumental food reflex].

Neuronal responses of the parietal associative cortex were studied in cat during differentiation, extinction and conditional inhibition of the placing reflex. It has been shown that this cortical area is involved in triggering and realization of the conditioned movement.

[Responses of the neurons of the parietal associative cortex of the cat brain to indifferent and conditioned acoustic stimuli].

Neuronal responses of the associative cortex (field 5) to indifferent and to conditioned sound stimuli were studied. The number of neurons responding to the conditioned sound during classical reflex increased two times. A percentage of inhibitory responses of neurons to conditioned acoustic stimulus during placing reflex grew.

[Reactions of neurons of the parietal association cortex (field 5) of the cat brain during the performance of conditioned reflex movement].

Responses of 160 neurons of the cat parietal cortex were studied during food instrumental reflex (placing reaction). 49% of them changed the discharge frequency before the movement initiation. Activation responses prevailed.