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B M Slotnick

Publications and source records attributed to B M Slotnick.

At least 37 records · Page 2Linked to original sources
PubMed1992

Decreased NaCl sensitivity in zinc-deprived rats.

NaCl thresholds and ability to discriminate between NaCl and sucrose were assessed in rats using an operant discrimination conditioning procedure before and during moderate and severe zinc deprivation and during zinc supplementation. NaCl thresholds were approximately 1 mM before dietary zinc manipulation. They increased in all zinc-deprived rats tested 10 and 17 days after initiation of deprivation but did not change in pair-fed controls maintained on supplemental zinc. Threshold changes were greater for those rats severely zinc deprived than for those only moderately deprived and were greater as the period of deprivation lengthened. Plasma zinc concentrations decreased significantly in deprived rats from values obtained at baseline, values in severely deprived rats being significantly lower than in those only moderately deprived. Although zinc-deprived rats discriminated NaCl from sucrose, they made more discrimination errors than controls. Following 24 days of zinc supplementation, previously deprived rats exhibited no significant improvement in gustatory performance, although their body weight increased and plasma zinc concentrations increased; but these later changes were not significant. These results demonstrate that zinc deprivation induces decreased gustatory sensitivity and confirm a role for zinc in taste.

Animals↗
PubMed1992

Olfactory bulb removal affects partner preference development and estrus induction in female prairie voles.

In female prairie voles (Microtus ochrogaster) bilateral olfactory bulbectomy reduced affiliative behavior, as measured by social contact, and prevented the formation of partner preferences. Unilateral olfactory bulb removal did not significantly influence affiliative behavior, but did inhibit partner preferences. Bilateral, but not unilateral, bulbectomy significantly reduced the proportion of females exhibiting behavioral estrus following male exposure. In contrast to affiliative and sexual behavior, parental behavior was not significantly affected by either bilateral or unilateral olfactory bulbectomy. These results suggest that divergent sensory-neural pathways underlie social, sexual, and parental behaviors in this species.

Aggression↗
PubMed1992

Olfactory pathways and the sense of smell.

Rats were trained using operant conditioning to detect isoamyl acetate vapor generated by an olfactometer. They received lesions of olfactory pathways and were tested for retention of the odor detection task and trained on two-odor tasks. Deficits in odor detection and two-odor discrimination were related to the extent to which lesions disconnected the olfactory bulb from the forebrain. Transection of only the lateral olfactory tract, only the anterior limb of the anterior commissure, or lesions of the olfactory tubercle had little effect but combined lesions of these structures produced severe deficits in both odor detection and discrimination. Only rats with almost complete transection of the olfactory peduncle or cortex were anosmic; those with transections that spared a small segment of tissue between the olfactory bulb and olfactory cortex had detectable olfactory function. The results are discussed with regard to efferent connections of the olfactory bulb.

Animals↗
PubMed1991

Olfactory projections to the hypothalamus.

Electrophysiological recording, together with anterograde and retrograde axonal tracers, was used to provide a comprehensive description of the origin and distribution of the olfactory input to the lateral hypothalamus. This input was much more substantial to the caudal part of the hypothalamus than to the rostral part and originates from several different areas of the olfactory cortex. Positive responses to electrical stimulation of the olfactory bulb were found consistently in the postero-lateral hypothalamus, but only occasionally at more rostral levels. In agreement with this, injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) in the posterior half of the lateral hypothalamus labeled cells in four cortical areas that receive input from the olfactory bulb: the anterior olfactory nucleus, the piriform cortex (in the deepest layer or ventral endopiriform nucleus), the olfactory tubercle (in the deep polymorphic layer), and the anterior cortical nucleus of the amygdala. Injections of WGA-HRP in the anterolateral hypothalamus labeled cells only in the anterior cortical nucleus of the amygdala. Anterograde axonal tracing confirmed these projections. Injections of 3H-leucine in the anterior olfactory nucleus, the piriform cortex, and the olfactory tubercle produced axonal label that was light and confined to the medial forebrain bundle in the rostral hypothalamus but was more substantial and extended throughout the lateral hypothalamic area caudally. Injections in the anterior cortical amygdaloid nucleus labeled axons in the anterior hypothalamus and in the premammillary nuclei as well as in the posterolateral hypothalamic area. In addition, a projection was demonstrated to the nuclei gemini from the polymorphic zone deep to the olfactory tubercle. Injections of two fluorescent retrograde tracers into the mediodorsal nucleus of the thalamus and the posterolateral hypothalamus showed that cells projecting to both diencephalic sites were intermingled in all of the olfactory cortical areas except the anterior olfactory nucleus, where cells were labeled only from the hypothalamus. In the deep layer of the piriform cortex and in the anterior cortical amygdaloid nucleus cells were also double labeled, indicating that they send collateral axons to both parts of the diencephalon.

Amygdala↗
PubMed1991

Olfactory learning and odor memory in the rat.

Rats were trained on a series of 9 tasks, each of which required discrimination among 8 different and unique odors. Discrimination accuracy improved across successive problems and, by the end of training, most rats made few errors after their initial exposure to each new odor. Despite the number of stimuli to be discriminated, this acquisition of a learning set was not appreciably different from that demonstrated in an earlier study that used only 2 odors per task. In subsequent retention tests, most rats also showed excellent memory for odors used in prior problems.

Animals↗
PubMed1991

Transection of the chorda tympani and insertion of ear pins for stereotaxic surgery: equivalent effects on taste sensitivity.

NaCl and sucrose absolute detection thresholds were determined in rats with bilateral transection of the chorda tympani nerve (group CT) and those treated by having stereotaxic ear pins inserted into the auditory canal and through the tympanic membrane (group EP). Relative to controls, each experimental group had deficits in acquisition of the NaCl detection tasks and higher NaCl thresholds, but had no significant deficits in the sucrose detection tasks. There were no differences between the CT and EP groups on any measure of performance. The performance of rats with unilateral CT or EP treatment was identical to that of controls for high concentrations of NaCl, but somewhat poorer on near threshold concentrations. These results (A) confirm prior reports for a specific role of the CT in NaCl detection and (B) indicate that the use of ear pins in stereotaxic surgery may disrupt CT function with a resultant decrease in NaCl sensitivity.

Animals↗
PubMed1990

Odor memory and odor learning in rats with lesions of the lateral olfactory tract and mediodorsal thalamic nucleus.

Rats with posterior transection of the lateral olfactory tract (LOT), lesions of the mediodorsal thalamic nucleus (MD), or with combined lesions of these structures were tested for retention of a preoperatively learned multiple odor discrimination task, acquisition of 3 simple 2-odor discrimination problems, and reversal of the last problem of the series. Compared to controls, rats with transection of the LOT had no deficits in any task. Those with MD lesions had no deficits in retention but moderate deficits in acquisition of novel odor discriminations and a severe deficit in reversal learning. Rats with combined LOT and MD lesions had no retention of the preoperatively learned task but their performance on the remaining problems was similar to that of rats with only MD lesions. These results suggest that neither the olfactory thalamocortical projections nor those to the periamygdaloid or entorhinal cortex are essential for storage and/or recall of an olfactory procedural memory task. Performance on the postoperative acquisition tests indicate that the thalamocortical but not the limbic olfactory projections play an important role in olfactory discrimination learning.

Animals↗
PubMed1990

Finding the base of the brain.

An electrode carrier mounted in a T-slot holder is described. An electronic circuit detects the vertical displacement of the carrier in the T-slot when an electrode encounters the base of the skull. Use of this vertical coordinate can reduce errors in locating structures at or close to the base of the brain.

Animals↗
PubMed1990

Rats with one olfactory bulb removed and the contralateral naris closed can detect odors.

Rats with one olfactory bulb removed were trained to detect 0.5%-0.005% concentrations of amyl acetate. These rats had only a slight decrement in performance when the naris ipsilateral to the intact olfactory bulb was closed. Thus, vapors inhaled through one naris can stimulate olfactory receptor neurons in the contralateral nasal vault. This internasal stimulation is probably mediated by the nasopharyngeal canal or nasopharynx.

Animals↗
PubMed1989

Odor-induced metabolic activity in the olfactory bulb of rats trained to detect propionic acid vapor.

The pattern of glucose metabolism in the glomerular layer of the main olfactory bulb was studied in rats trained to sample brief odor stimuli. After injection with [14C]2-deoxyglucose (2-DG). 5 rats were tested for discrimination of propionic acid from air. Over the 45 min test period rats sampled the stimulus for 0.5-0.8s during each trial and their total exposure to the stimulus was 53-147 s. A discrete focus of increased glucose metabolism was found in the central dorsomedial sector of the glomerular layer in each animal. The position of this focus and the overall pattern of glomerular layer activity was essentially identical to that obtained in 4 control rats which were exposed passively to alternating 5 min periods of the odor and clean air for 45 min. The size of the primary focus was only slightly smaller in the trained rats, despite the large difference in total exposure time. The absence of olfactory adaptation during the behavioral tests and the similar pattern of 2-DG uptake in controls and trained animals indicate that adaptation does not play a significant role in the patterns of glucose metabolism induced in the glomeruli of the olfactory bulb by extended exposure to an odor.

Animals↗
PubMed1989

Odor masking in the rat.

A computer controlled behavioral apparatus and olfactometer were used to determine the olfactory threshold of rats for propionic acid and to determine their ability to discriminate propionic acid in binary mixtures that contained the dissimilar odorants, limonene or carvone, or a similar odorant, acetic acid. The concentration of propionic acid that rats required to discriminate this substance from the other odorants was substantially above that of the threshold concentration, the increase being greatest with acetic acid. The increased levels of propionic acid needed for detection of this odorant in mixtures is attributed to masking by the other components. This study represents the first time behavioral methods have been used to demonstrate masking with odor mixtures in a rodent. The results indicate that it should be possible to use behavioral methods to define conditions for odor masking in animals so that physiological studies of the underlying mechanisms can be achieved.

Acetates↗
PubMed1988

Zinc deficiency decreases the activity of calmodulin regulated cyclic nucleotide phosphodiesterases in vivo in selected rat tissues.

The effect of zinc deficiency on calmodulin function was investigated by assessing the in vivo activity of two calmodulin regulated enzymes, adenosine 3',5'-monophosphate (c-AMP) and guanosine 3',5'-monophosphate (c-GMP) phosphodiesterase (PDE) in several rat tissues. Enzymatic activities in brain, heart, and testis of rats fed a zinc deficient diet were compared with activities in these tissues from pair fed, zinc supplemented rats. In testis, a tissue in which zinc concentration decreased with zinc deficient diet, enzyme activities were significantly decreased over those in rats who were pair fed zinc supplemented diets. In brain and heart, tissues in which zinc concentrations did not change with either diet, enzymatic activities between the groups were not different. These results indicate that zinc deficiency influences the activity of calmodulin-regulated phosphodiesterases in vivo supporting the hypothesis that zinc plays a role in calmodulin function in vivo in zinc sensitive tissues.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1987

In vivo effects of zinc deficiency on calmodulin concentrations in selected rat tissues.

Two groups of male Sprague-Dawley rats, one fed zinc-deficient diet, ad libitum, the other, pair-fed with the same diet, but given supplemental zinc in the drinking water (8 mg Zn++/ml) were studied. After ten weeks of diet, rats were exsanguinated and zinc and calmodulin concentrations in brain and testis were measured. Mean zinc concentration in testis was significantly decreased in rats fed zinc-deficient diet without supplemental Zn++, but mean zinc concentration in brain was not different. Similarly, mean calmodulin concentration in testis was decreased in rats fed zinc-deficient diet without supplemental Zn++ whereas mean calmodulin concentration in brain was not different. Distribution studies of zinc and calmodulin showed that both zinc and calmodulin were released more freely into soluble fractions of testis in rats fed zinc-deficient diet without supplemental Zn++. These results indicate, for the first time in in vivo studies, that zinc influences the calmodulin content of testis.

Animals↗
PubMed1987

Detection of propionic acid vapor by rats with lesions of olfactory bulb areas associated with high 2-DG uptake.

This study tested the functional significance of recent 2-deoxyglucose (2-DG) results demonstrating a discrete focus of activity in the olfactory bulb of rats exposed to the vapor of propionic acid. Rats with lesions that destroyed this area of the olfactory bulb performed as well as did sham operated and lesioned controls in detection of amyl acetate, butanol, geraniol, propionic acid, and on a test for propionic acid threshold. Our results demonstrate that an area of the olfactory bulb containing a major focus of metabolic activity induced by exposure to an odor can be removed without producing a deficit in the detection of that odor.

Animals↗
PubMed1987

Nipple attachment and survival in neonatal olfactory bulbectomized rats.

Seven-day-old rat pups were olfactory bulbectomized, cortical lesioned, or sham lesioned, tested for nipple attachment 24 hr after surgery, then housed with their dam and weighed daily for the next 7 days. On the basis of histological findings the bulbectomized animals were divided into two subgroups: Those with removal of all olfactory bulb tissue (n = 9) and those in which some cellular elements remained in the lesioned area (n = 7). There were no differences between sham and cortical lesioned groups for nipple attachment behavior or weight gain. The completely bulbectomized pups did not show nipple attachment, lost weight each day, became moribund and had to be sacrificed by the fifth postoperative day. Deficits in incompletely bulbectomized pups were somewhat less severe and each of these survived and maintained or gained weight in the latter part of the test period. These results suggest that suckling may be critically dependent upon olfaction in 8 day or older pups and that significant savings in this behavior may be mediated by small remnants of olfactory bulb tissue.

Animals↗
PubMed1987

Suckling behavior in rat pups with lesions which destroy the modified glomerular complex.

Seven-day-old sham operated rats and those with lesions of the rostral medial, lateral, or posterior medial olfactory bulbs were tested postoperatively for nipple attachment behavior and weighed daily. The posterior medial lesions included the area of the modified glomerular complex (MGC), a region of the bulb that has been implicated in suckling behavior. There were no significant differences among groups in nipple attachment latency or weight gain. These results do not support the notion that the MGC is essential for suckling in neonatal rats.

Animals↗
PubMed1987

The horizontal-vertical illusion: independence of line bisection and a comparison line.

Undergraduate students in social science and architecture did not differ in their accuracy of adjusting the vertical lines of L and inverted-T figures to be equal to a 1-in. horizontal line (the adjustment task) or in producing a 1 in. long line in the vertical or horizontal plane on a blank sheet of paper (the production task). In the adjustment task vertical lines were made significantly shorter than the horizontal comparison line and the shortening of the vertical line was significantly greater for the inverted-T than for the L-figure. In the production task lines drawn in the horizontal plane did not differ significantly from 1 inch but those drawn in the vertical plane were significantly shorter than 1 inch. Further, the magnitude of this error was equal to that obtained with the inverted-T figure. These results demonstrate that, while line bisection (the bisection of the horizontal by the vertical in the inverted-T figure) contributes to the horizontal-vertical illusion, the illusion clearly exists in the absence of a comparison line and can be accounted for as an overestimation of the vertical line.

Adult↗