Olfactory Bulb Lesions Research Articles

Effects of neonatal (day 10) olfactory bulb lesions on social behavior of female golden hamsters (Mesocricetus auratus).

Effects of neonatal (day 10) olfactory bulb lesions on social behavior of female golden hamsters (Mesocricetus auratus).

Effects of olfactory bulb lesions on brain monoamines

Unilateral olfactory bulb lesions in the rat caused a selective decrease and increase of norepinephrine in the telencephalon and the brainstem, respectively. There were no changes in the concentration of dopamine or serotonin in the ipsilateral telencephalon or brainstem of rats with unilateral lesions. The increase in brainstem norepinephrine concentration in animals with olfactory bulb lesions was reduced when the animals were kept 5 to a cage post-operatively, rather than in isolation.

Passive avoidance in septal and anosmic rats using quinine as the aversive stimulus

The purpose of the present study was to compare septal lesioned rats with operated and normal control rats in a passive avoidance task using quinine rather than electric shock as the aversive stimulus. Since there are behavioral similarities produced by septal and olfactory bulb lesions, a group of anosmic rats were also included. It was found that both the septal lesioned and the anosmic rats perseverated in running to the drinking tube after quinine was introduced. The septal rats also consumed more once they reached the drinking tube. These results were interpreted as being congruent with the notion that a response inhibition deficit results from septal lesions.

The effects of septal and olfactory bulb lesions on stimulus reactivity

The present study consisted of 5 experiments which investigated the reactivity of septal and anosmic rats to taste, light, sound and shock stimuli. Septal rats were reliably hyperreactive to thermal, sound, and shock stimulation, but not to taste or light stimuli. Previous research has shown that septal rats are hyperreactive to taste stimuli and light stimuli and the equivocal results may be due to procedural or strain differences. It was also found that septal rats were quite able to inhibit their responses in the tasks used and the explanation that septal lesions destroy some inhibitory mechanism was not supported by these studies. Anosmic rats were hyperreactive to heat and shock stimulation but not to taste, light or sound stimulation.

A short-term effect of amygdaloid lesions on food intake in the rat

Relatively small bilateral lesions in the amygdala resulted in a significant decrement in food intake in rats by comparison with similar lesions in the septal region or olfactory bulbs, or with a sham operation. This decrement was reflected in a relative decrease in body weight during the first 5 postoperative days, after which the rate of weight gain appeared to be normal. It is suggested that amygdaloid lesions may induce specific effects on food intake, and possibly other aspects of behavior which are related to the immediate sequelae of the lesion but not necessarily to interruption of amygdaloid circuitry. Water intake was significantly, and approximately equally, depressed in both the groups with septal and amygdaloid lesions. but to a lesser extent in the group with olfactory bulb lesions.

Aggressive behavior in the rat: Effects of isolation, and olfactory bulb lesions

Forty-nine male hooded rats 84 or 94 days of age were used as subjects. Ss were housed individually or in groups for 1 month and were then subjected to an olfactory bulbectomy or a sham operation. They were again housed either individually or in a group cage for 1 month. Ss were then tested for mouse killing, frog killing, reactions to a gloved hand including squealing, escape, and biting, intermale aggression and shock-induced aggression. Results indicate that biting the glove was the only type of aggressive behavior significantly affected by olfactory bulb lesions. Postoperative isolation increased mouse killing, and escape from the gloved hand and the number of bites on the hand. There was also a significant operation by postoperation isolation interaction for number of bites on the glove. Mouse killing and frog killing were significantly correlated as were escape and squealing; escape and bites; and bites and mouse killing. Intermale aggressive behavior was notably absent and was unaffected by any condition. It was concluded that this study adds further evidence that aggression is not a unitary phenomenon and that different manipulations differentially affect different kinds of aggression.

Mechanism of changes in brain norepinephrine levels following olfactory bulb lesions

Rats killed 27 days after an olfactory bulb is transected show characteristic alterations in the quantities of norepinephrine in certain brain regions (1,2). In the ipsilateral telencephalon, the locus of most of the axons which leave the olfactory bulb (3), norepeniphrine levels decrease. This effect probably reflects a loss of noradrenergic nerve endings, since the ability of the telencephalon to take up and retain 3H-norepinephrine placed in the lateral cerebral ventricles also declines. In the brain stem, norepinephrine levels increase. This region is not known to receive a significant number of nerve fibers originating in the olfactory bulb (3); hence the elevation in its norepinephrine content must result from a trans-synaptic mechanism. This communication provides information on the time-course of the changes in brain norepinephrine levels after olfactory bulb lesions and on the anatomic and biochemical mechanisms responsible for these changes.

Effect of lesions in the septal area and olfactory bulbs on sodium chloride intake

Spontaneous sodium chloride intake in rats with lesions in the septal area or olfactory bulbs and normal rats were studied. Normal rats prefer 1% NaCl solutions when allowed to choose concentrations from 0.5%–3% NaCl and tap water. Animals with septal area or olfactory bulb lesions increase the 1% NaCl intake as compared with prelesion values. This effect was still evident 4 months later. The high NaCl intake is not related to an altered renal sodium excretion. The sodium depletion leads to a significant increase of Na intake in all animals, but the highest values are observed in lesioned animals. In Na-depleted rats, sodium overload reduced the sodium ingestion to normal values. It is postulated that, in the regulation of Na intake, a dual mechanism exists, inhibitory and stimulatory, and that the limbic system may be related to the inhibitory influences.

The olfactory bulb lesion in the hibernating squirrel (Citellus lateralis) infected with coxsackievirus B-3. II. Immunological study.

The immunological response was studied in the adult hibernating squirrel (Citellus lateralis) infected with coxsackievirus B-3. The complement activity was considerably reduced between the 4th and 9th day of infection, but was restored to the normal level by the 11th day. The neutralizing antibody was first detected in the blood on the fourth day, reached an average ND50 of 10−2.62 on the seventh day after inoculation, and remained at this level.Gamma globulin was demonstrated in the infected olfactory bulb by the direct fluorescent antibody method on the seventh day after inoculation. The specific fluorescence appeared as a surface staining of the infected granule cells, cellule nervose piccole, and within numerous inflammatory cells. On staining with methyl green – pyronin these cells resembled the antibody-producing cells in the spleen.A sequential correlation existed between the development and appearance of the gamma-globulin-producing cells in the spleen and the olfactory bulb which indicated that the lymphoid cells infiltrated into and contributed to the tissue destruction in the olfactory bulb of the infected squirrel.

Interactive effects of experience and olfactory bulb lesions in male rat copulation

Abstract Experiment 1 measured the effects of unilateral and bilateral olfactory bulb ablations in male rats with limited prior copulatory experience. Bilateral lesions produced gross prolongations of first and second series ejaculation latencies. When a second female was introduced to the males, however, bilaterally lesioned animals were not at a copulatory disadvantage. In Experiment 2 virgin males were tested for copulatory behavior following olfactory bulb lesions. The probability of ejaculation, but not of intromission, was significantly reduced for bilaterally lesioned males.

Mating behavior of male rats after olfactory bulb lesions

Abstract Interruption of the afferent olfactory connections by lesions in the olfactory bulbs caused a marked impairment of the sexual behavior of male rats. The animals showed a prolonged latency in their responses to estrous females, a reduction in the number of ejaculations and an increased tendency to remain totally unresponsive to the sexual stimulation. It is suggested that olfactory impulses exert a strong influence upon the preoptic-anterior hypothalamic region, which is known to be of crucial importance for mating behavior.

Some olfactory pathways in the rabbit brain.

AbstractThe degeneration pattern in the rabbit following transection of the olfactory bulb or peduncle at various levels was studied by the Laidlaw method of Nauta. Degenerating axons were observed in the crossing of the anterior limb of the anterior commissure and in the lateral olfactory tract following olfactory bulb lesions which did not damage the anterior olfactory nucleus. Evidence was found for termination of the olfactory tract fibers over all parts of the anterior olfactory nucleus, the rostral and lateral parts of the olfactory tubercle, the anterior continuation of the hippocampus, the nucleus of the lateral olfactory tract, and the prepyriform areas 1, 2, and 3, the periamygdaloid areas 1, 2, part of 3, and 5, and the entorhinal axeas 1, 2, and 4 of Maximillian Rose. When the anterior olfactory nucleus was damaged degeneration was found in the contralateral olfactory bulb and anterior olfactory nucleus and parts of the ipsilateral neocortex adjacent to the rhinal fissure, limbic system (medial septal nucleus and anterior continuation of the hippocampus), pyriform lobe cortex, and lateral preoptic area. The results differ in particulars from those of previous investigators.