Frederick P. Gault

Electrical activity of the olfactory system.

Abstract Data have been presented concerning the relationship of nasal air flow to electrical activity in the olfactory system. The close correspondence between the Ottoson slow potential from the bulb and respiratory activity suggests that this slow potential is an excellent measure of respiration. The bursting activity at approximately 40 c/sec in the olfactory bulb appeared to be closely related with the rate and amplitude of the slow potentials, indicating that the slow potential was necessary for the elicitation of the 40 c/sec activity. Similar 40 c/sec activity in the basolateral amygdala was found to occur only at times when this activity was evident in the bulb, but did not occur invariably when 40 c/sec bulb activity was seen. In the shift from sleep to arousal, it was seen that the 40 c/sec activity in the bulb and amygdala did not occur until the first inspiratory cycle. Sniffing associated with active olfactory exploration was evident in the slow potential recordings and was associated with greatly increased 40 c/sec activity in both the bulb and amygdala.

Aphagia and adipsia following lesions of the amygdala

Lesions of the medial nucleus of the amygdaloid complex in rats produces aphagia and adipsia.

Nasal air flow and rhinencephalic activity

Abstract This study has investigated factors involved in the elicitation of 40 c/sec spindling in the olfactory bulb and amygdala utilizing both acute and chronic animals. The olfactory bulb 40 c/sec activity which has been identified as a correlate of emotional behavior appears indistinguishable from olfactory induced activity. Drugs such as cocaine and barbiturates affect the 40 c/sec responses in a similar fashion in both chronic and acute preparations supporting the contention that the “emotional” role of such activity is mediated by changes in the respiratory processes.

Reticular formation control of vestibular system

Abstract In seventeen encephale isole cats, horizontal nystagmus elicited by electrical stimulation of the lateral vestibular nucleus was found to be modulated by stimulation of the mesencephalic reticular formation at the stereotaxic plane A-O. Four discrete effects were seen: with medial superior stimulation the contralateral vestibular complex was inhibited; medial inferior placements caused a facilitation of the contralateral nucleus; placements slightly lateral to the above produced inhibition of the ipsilateral complex; and lateral placements ventral to the lateral lemniscus produced a facilitation of the ipsilateral vestibular nucleus. In view of the dense fiber pathways to and from the cerebellum in this area and the connections of the cerebellum with the vestibular complex, it is possible that this effect might be mediated in part via the cerebellum and in part via the reticular formation.

The relationship of nystagmus to lateral vestibular nucleus stimulation

Abstract Electrical stimulation of the lateral vestibular nucleus was employed to elicit nystagmus in twenty-one acute cat preparations. Low intensity (2 v; 0.05 mamp) of 5-sec duration produced nystagmus with the fast component toward the side of stimulation; frequencies between 200 and 400 cycle/sec were most effective. Medium strength stimuli (9 v; 0.5 mamp) produced ocular tremor during stimulation and an afternystagmus in the same direction. Intense stimuli (15 v; 0.8 mamp) produced a reversal of afternystagmus, following the same response elicited with medium strength stimuli. Prolonging low-intensity stimulation time above 5 sec could simulate stimulations at higher intensities. The nystagmus response elicited by medium strength stimuli remained reproducible and constant over several hours.

The effect of ethyl alcohol on electroencephalographic sleep cycles in cats

EEGs taken from four sleeping cats for three control and four alcohol consecutive nights show that if 1 gm ethanol/kg body weight is administered 15 min. prior to sleep, Stage 1 REM time decreases from control values the first two alcohol nights but returns to control levels on the third and fourth alcohol nights. This pattern of change in REM time is the same as that found in humans. The REM time pattern is effected by a change in length rather than in numbers of REM periods. These data support the use of cats in establishing a mechanism for REM sleep which can be extrapolated to humans.

Physiology of the lateral vestibular nucleus

Abstract Simultaneous bilateral stimulation of the lateral vestibular nucleus in cats demonstrated that nystagmus evoked from each nucleus could be algebraically summated. This precise interaction was destroyed by labyrinthectomy which produced a resting nystagmus contralateral to the lesion. Resting nystagmus could be potentiated or inhibited by stimulating the appropriate nucleus. Atropine eliminated and amphetamine potentiated resting and elicited nystagmus. These data suggest a resting labyrinthine discharge which is necessary for vestibular stability in the intact animal and which enters the ipsilateral vestibular nucleus from which projections—possibly via the reticular formation—inhibit the contralateral lateral vestibular nucleus.

An implanted electrode for recording both rapid eye movements and muscle tone during sleep

Abstract A single electrode pair which permits recording of both cephalic muscle tone and rapid eye movements is described. Use of this method for recording channels, a animals provides the use of fewer recording channels, a method for accurately monitoring the REM state, and an easy means of comparing rapid eye movements with cephalic muscle tone.

A simple device for controlling transients in auditory stimuli

Abstract Description of a simple, inexpensive method by which click transient can be eliminated. The method consist of inserting a resistor type photocell in series with the output of an audiogenerator.

Intracranial brain stimulation and suppression of behavior

Hungry rats were trained to lever press for food on a variable interval schedule. Subsequent to attaining stable rates, stimulation of either the nucleus Ventralis Postero Lateralis of the thalmus, or of the Central Grey substance was introduced on a response contingent basis. The effect of such stimulation on the response rate for the food reinforcement provided an index of the aversiveness of the brain stimulation. For each animal, lever pressing rate is a decreasing exponential function of the intensity of stimulation either to the VPL or the CG. Once behavior has been suppressed, rate of return to baseline is an inverse, monotonic function of punishment intensity.