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

Found that, after neonatal (Day 10) bilateral olfactory bulbectomy (BOB; n = 16), adult female golden hamsters' scent marking and defense behavior to males was reduced relative to sham (n = 13) or neocortically lesioned (n = 11) littermate controls. The BOB aggressive and sexual behavior appeared grossly normal-15 were successfully mated, but 5 destroyed their litters. After mating, controls became more aggressive but BOB aggression decreased and had disappeared by the 2nd wk. of pregnancy. All groups ceased scent marking after mating, but controls returned to premating levels during lactation. The BOB Ss showed no scent marking, defense, or aggression throughout lactation. Unilateral olfactory bulbectomy of 6 Ss also eliminated normal social behavior during lactation, suggesting that not all the behavioral effects of olfactory damage can be attributed to anosmia. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Marked restoration of density and total number of mature (knob-bearing) olfactory receptor neurons in rats recovering from early hypothyroid-induced growth retardation

Our recent studies have shown that restoration of thyroid function in developing hypothyroid rats results in upregulation of olfactory neurogenesis and compensatory proliferation of olfactory receptor neurons (ORN) in the olfactory epithelium (OE) (Paternostro and Meisami, Dev. Brain Res., 76 (1993) 151-161; ibid., 83 (1994) 151-162). It was not clear, however, whether the newly forming ORNs undergo complete maturational stages. To determine the effects of restoration of thyroid function on maturation of ORNs, the density and total number of mature ORNs were estimated in the OE of euthyroid and hypothyroid rats at postnatal days 1, 12, 25 and 90 and the results were compared with those in rats allowed to recover from early thyroid deficiency at weaning (day 25). As a marker for mature ORNs, and on the basis of one olfactory dendritic knob per ORN, the density and total number of the olfactory knobs were determined in the entire extent of the OE covering the nasal septum. Hypothyroidism was induced by adding propylthiouracil (PTU) to the drinking water (1 g/l) from birth until days 12, 25 or 90 of age. Recovery from hypothyroidism was induced by withdrawal of PTU at day 25, leading to restoration of thyroid function and somatic growth recovery. The density of olfactory knobs was determined in 1 microm semi-thin sections stained with toluidine blue. In the normal rats, the number of olfactory knobs (= mature ORNs) increased 8.5- and 3-fold during postnatal days 1-25 and 25-90 respectively, reaching a mean value of 4 X 10(6)/septal OE, compared to 2.8- and 1.4-fold, respectively, for the hypothyroid rats. This led to deficits of 51% and 76% in the number of mature ORNs in the 25- and 90-day-old hypothyroid rats. In rats allowed to recover, the number of mature ORNs increased 4.5-fold during postnatal days 25-90 (3 X > hypothyroid rats and 1.5 X > controls). The results indicate marked upregulation of the maturational process of the ORNs and their compensatory accretion within the OE of the recovery group. The recovery process was not complete however, as indicated by a remaining deficit of about 25% in the total number of mature ORN, compared to normal 90-day controls. Thus thyroid hormones are essential for accretion of new mature ORNs in both the suckling and postweaning rats. Also, the ORNs show a remarkable ability to recover from severe early hypothyroid-induced growth retardation and attain normal mature state.     

Trigeminal denervation and operant behavior in the rat.

39 male Wistar rats underwent selective sectioning of trigeminal sensory and motor nerves in 2 experiments to examine the contribution of the sensorimotor system to the control of instrumental responses reinforced with food or water. It was hypothesized that trigeminal denervation would disrupt motivational systems mediating Ss' thirst and hunger. Results show that unilateral sectioning of either Section V sensory or V motor nerves had no significant effect on leverpressing. Bilateral sectioning significantly reduced leverpressing, and the deficit was greatest in Ss with trigeminal motor nerve sectioning. It is concluded that trigeminal orosensory or oromotor denervation disrupts performance on a food- or water-reinforced task in which execution does not require a trigeminally mediated response. Findings are discussed in terms of motivational and reinforcement accounts of instrumental learning. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laboratory observations of aggregative behavior of garter snakes, Thamnophis sirtalis: Roles of the visual, olfactory, and vomeronasal senses.

Two experiments determined (a) whether male garter snakes require a functional vomeronasal or olfactory system to return to previously preferred shelter locations and (b) the sensory modalities used to aggregate in the absence of previously deposited chemical cues. In Exp I, 22 male garter snakes with vomeronasal nerve lesions did not return to previously preferred shelter locations when tested individually. However, when tested with a group that included 9 control Ss, they returned to previously preferred shelters. The shelter-selection behavior of Ss with olfactory nerve lesions improved postoperatively, whereas the behavior of Ss with sham lesions was unchanged. In Exp II, 32 Ss were tested for aggregation in aquaria in which the substrate and other contents were cleaned between trials. After blindfolding or olfactory nerve cuts, Ss aggregated at normal levels. When Ss' vomeronasal ducts were sutured closed, aggregation scores were significantly depressed, although 2 of the 3 groups with vomeronasal duct sutures did aggregate just above change levels. Results from both studies indicate that use of chemical signals by garter snakes in shelter selection and aggregation is mediated by the vomeronasal system and that neither the olfactory nor the visual system is critical for these behaviors. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory functioning before and after temporal lobe resection for intractable seizures.

An olfactory test battery was administered monorhinically to 21 epilepsy patients prior to and 6 mo after unilateral medial temporal lobe resection for treatment of intractable seizures. 33 matched control Ss were also tested. Presurgically, controls and patients exhibited normal sensitivity for 1-butanol. Patients performed at levels significantly below controls on tests for odor discrimination, odor memory, and odor naming. Left-resected patients did not show significant changes following surgery. Right-resected patients demonstrated significant right nostril decline. Postsurgical changes demonstrated by the right-resected group were not attributable to deficits in primary sensory function or to deficits in cognition brought on by surgery. These findings imply that right medial temporal lobe structures play a greater role in olfactory processing than do corresponding structures in the left hemisphere. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory basis for the delayed onset of maternal behavior in virgin female rats: Experimental effects.

A previous study showed that intranasal zinc sulfate (ZnSO4) treatment shortens the latencies for the onset of maternal behavior in nonpregnant rats. The present study attempted to determine whether after recovery from the effects of ZnSO4 treatment, the latencies for maternal behavior increased. In Exp I, with 28 Charles River female rats, nonpregnant Ss were intranasally infused with ZnSO4 or air were left untreated and exposed to pups starting 48 hr later. Olfactory discrimination tests using chocolate bits were done simultaneously. The ZnSO4 treatment resulted in short latency maternal behavior (1.1 days) compared with latencies of control Ss (3.8 days), but neither group showed any loss of olfactory discrimination. 3 wks later, ZnSO4-treated Ss showed increased latencies for all but retrieving, while control groups showed decreased latencies for all maternal behaviors. In Exp II, with 13 nulliparous Charles River females, intranasal ZnSO4- and air-treated Ss were given olfactory discrimination tests under food deprivation, using chocolate bits and guinea pig pellets. Choice of guinea pig pellets was more severely affected than choice of chocolate bits, but recovery of the discriminations was complete in 4-5 days. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of androgen on marking and aggressive behavior of neonatally and prepubertally bulbectomized and castrated male gerbils.

Exp I assessed the role of olfactory and androgenic influences on the development of scent-marking and aggressive behavior of 69 male gerbils. Ss were bilaterally bulbectomized, unilaterally bulbectomized, castrated, given a combination of bulbectomy and castration, or given a sham operation at 2 days of age. Marking and fighting were recorded prior to and after androgen treatment in adulthood. Postoperative tests revealed that neonatal olfactory bulb removal, alone or in combination with castration, virtually eliminated scent-marking and fighting. Treatment with testosterone propionate (TP) in adulthood was ineffective in facilitating marking after neonatal castration, bulbectomy, or their combination. However, Ss given TP did exhibit increased aggressiveness. The most striking increases were found in bulbectomized and bulbectomized-castrated Ss. In Exp II (117 Ss), bulbectomy, castration, or their combination at 35 days of age also reduced both marking and fighting. Androgen treatment in adulthood did, however, fully restore marking in all groups to control levels with the exception of bulbectomized-castrated Ss. Fighting was increased to extremely high levels following TP treatment in bulbectomized and bulbectomized-castrated Ss. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental analysis of behavioral dysfunction in rats with septal lesions.

At 7 days of age, 48 male Long-Evans hooded rats received lesions of the septal nuclei or control operations. Ss then received 30 hrs of training on a DRL 20-sec schedule for 1 hr/day beginning at either 27 or 96 days of age. At 126 days of age, all Ss received 10 additional training sessions. After operant testing, all Ss received 10 additional training sessions. After operant testing, all Ss were tested on spontaneous alternation, spatial reversal, and passive avoidance. Results indicate that on a DRL 20-sec schedule Ss that received lesions of the septum neonatally and were tested at different ages performed in a similar manner. Approximately 50% of the Ss with lesions of the septal nuclei reached efficiency levels comparable with those of normal controls. When tested for retention, these efficient Ss still performed similarly to normal Ss. Ss with septal lesions were facilitated in the acquisition of a spatial habit, were deficient in spatial habit reversal, were less likely to demonstrate spontaneous alternation, and were deficient in passive avoidance. It is concluded that neonatal lesions of the septal nuclei produce permanent behavioral impairments on a diversity of measures and that, although juvenile animals with limbic system damage often manifest behaviors different from adult Ss, the difference is not evident during operant testing (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time course of effects of septal lesions on avoidance, response suppression, and reactivity to shock.

Conducted 4 experiments with a total of 99 male albino Sprague-Dawley rats with septal lesions and 76 sham-operated controls. Ss tested 5 or 10 days, but not 2 days, after septal lesions acquired a 2-way conditioned avoidance response faster than controls. Punishment in a passive-avoidance test was least effective in suppressing milk-licking 2 days after septal lesions, and increased in effectiveness as a function of time after surgery. All experimental Ss were significantly more reactive to footshock than controls in a jump-flinch test. Results support the hypothesis that different aversively-controlled behaviors are mediated by different mechanisms within the septum. (31 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of olfactory control of feeding-site selection in rat pups.

The results of 4 experiments provide 2 lines of evidence consistent with the view that development of olfactory control of feeding-site selection in Long-Evans rats depends on experiences during ontogeny. (1) Normally reared Ss preferred to eat at a feeding site where either an anesthetized conspecific or conspecific excreta were present rather than at a clean site, whereas Ss reared without contact with conspecifics were not influenced in their choice of feeding-site by these social stimuli. Ss allowed contact with conspecifics for only the 5 days immediately prior to testing exhibited, like normally reared Ss, a strong preference for feeding sites marked with social stimuli. (2) Exposure of Ss to an arbitrarily selected odor rendered that odor subsequently capable of influencing feeding-site selection. Comparison of results with those of similar studies, in which a different measure of pup olfactory preference was used, revealed that the factors affecting development of olfactory preference vary as a function of test situation. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pleasant activities and depression.

Examined the relationship between engaging in pleasant activities and mood as a function of age, sex, and diagnostic group. 90 male and female Ss, evenly divided into 3 age groups (18-29, 30-49, and 50 and over) and 3 diagnostic groups (depressed, nondepressed psychiatric, and normal controls) completed activity schedules and mood ratings for 30 consecutive days. Correlation with mood was obtained for total number of pleasant activities engaged in as well as for individual activities. Results indicate that (a) a substantial and significant relationship existed between mood level and number of pleasant activities engaged in for all groups, (b) psychiatric controls and Ss aged 30-49 had a significantly larger number of mood correlated items, and (c) depressed Ss engaged in fewer pleasant activities. Activities and events frequently associated with mood were categorized into 3 groups: incompatible affects, ego supportive, and social interaction. Treatment implications are discussed. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neonatal ablations of the gustatory neocortex in the rat: Taste aversion learning and taste reactivity.

Sprague-Dawley rats sustaining ablations of gustatory neocortex (GN) at 2, 10, 20, or 60 days of age were compared with control-lesion and anesthetized controls (N?=?151) in the acquisition and extinction of a learned taste aversion. Ss were also tested for taste preference across 5 concentrations of NaCl solution (.04, .08, .15, .3, and .6 M). Results indicate that GN ablation disrupted aversion acquisition and extinction regardless of age at surgery. Taste-response functions for solutions shown by all GN Ss mirrored those of controls: preference (relative to water baseline) for middle concentrations and rejection of the strongest concentration. It is suggested that the 20- and 60-day-old GN Ss were hyperresponsive to the suprathreshold concentrations of NaCl (excepting the .6-M concentration). The increased response to NaCl in 20- and 60-day-old GN Ss may have been related to the significant decreases in water consumption relative to that of controls. Water consumption of controls and GN Ss in 2- and 10-day-olds was essentially equal. It is concluded that infant ablation of the GN does not spare normal taste aversion learning and that rats with GN ablations, regardless of age at surgery, respond in a normal manner to the hedonic aspects of NaCl solutions. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholinergic receptor blockade impairs spatial localization by use of distal cues in the rat.

Studied spatial localization in the Morris water maze. 30 male Long-Evans hooded rats were required to escape from cool water by finding a submerged, invisible platform located at a fixed place. The start point randomly varied, and there were no local cues. After training, the platform was moved. Six Ss subjected to central cholinergic receptor blockade with atropine sulfate were compared with normal Ss and with 6 Ss receiving peripheral cholinergic blockade with atropine methylnitrate. The controls were a group of blind Ss and Ss for which the platform was moved from trial to trial. Results show that controls and the atropine methylnitrate Ss used a spatial mapping strategy to locate the platform. The atropine sulfate-treated Ss adopted a search strategy like that of the blind Ss and Ss for which the platform was randomly moved. Results support the idea that central cholinergic systems are important for spatial mapping, which demands the use of distal visual cues. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory regulation of maternal behavior in rats: I. Effects of olfactory bulb removal in experienced and inexperienced lactating and cycling females.

Used 57 Sprague-Dawley virgin female rats to study the effects of olfactory bulbectomy under various conditions. Bilateral bulbectomy induced either cannibalism or short latency maternal behavior in naive Ss. Following unilateral bulbectomy or 2-stage bilateral bulbectomy, short latency maternal behavior appeared but cannibalism did not. Pregnancy and parturition overcame cannibalism after bilateral bulbectomy in inexperienced Ss, but not in females exhibiting cannibalism as virgins. Experienced (2 days postpartum) bulbectomized Ss had shorter latencies for reinduction of maternal behavior than experienced intact Ss. Results suggest that olfactory bulbs have 2 functions in relation to maternal behavior: sensory (olfaction) and nonsensory. Female response to olfactory bulbectomy may be due to anosmia facilitating maternal behavior, or to removal of nonsensory influences resulting in cannibalism. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of the function of nerve growth factor in the olfactory tract of the mouse

The aim of this study was to examine the function of nerve growth factor (BGF) in the olfactory tract of mice. Using the mice which had received unilateral olfactory bulbectomy and in which antibodies to NGF had been continuously infused with into the contralateral olfactory blub, three kinds of analysis were performed: histological analysis of the olfactory epithelium by HE staining, immunohistochemical analysis of the olfactory epithelium using polyclonal antibodies to trk which forms the NGF receptor, and olfactory-mediated behavioral analysis with cycloheximide. These animals had been sacrificed at day 1, 3, 7, 14, 21 or 28. Several findings were obtained as a result of the above analysis. Degeneration of the olfactory epithelium and trk expression by the olfactory cells were observed on day 7, and the olfactory epithelium was incompletely regenerated on day 28. However, trk expression by the olfactory cell was still recognized and the olfactory function was not restored by day 28. These examinations suggest that NGF produced in the olfactory bulb was transported retrogradely to olfactory cells through the olfactory nerves, and was associated with sustaining the existence of those cells and with regenerating the olfactory tract after injury.     

Differential effects of prefrontal cortex ablation in neonatal, juvenile, and young adult rats.

Long-Evans hooded rats sustaining lesions in the medial (MF) or the orbital (OF) prefrontal cortex at various ages (10, 25, 40, or 60 days postnatally) were tested as adults on a series of behavioral tasks that are known to be sensitive to such lesions in adults. On spatial alternation learning, both the 40- and 60-day MF Ss were seriously impaired, whereas neither the 10- nor the 25-day MF Ss differed from controls. On a hoarding task, 25- and 60-day MF Ss hoarded less food than either controls or 10-day MF Ss. Lesions of OF cortex in males at 40 or 60 days significantly increased running-wheel activity; OF lesions in both sexes at 25 days of age or later decreased the rate of continuous reinforcement reacquisition relative to controls, whereas 10-day OF Ss did not differ from controls on either task. Thus, Ss with lesions of either frontal area at 10 days of age showed complete behavioral sparing on all measures. The effects of lesions at later ages varied with the behavioral task employed and with lesion locus. Although the 10-day Ss received a somewhat longer postoperative recovery interval than most of the later operates, these results cannot be explained on the basis of recovery time alone. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of olfactory bulbectomy on social behavior of male guinea pigs ( Cavia porcellus ).

Studied the effects of olfactory bulbectomy on social behavior in 16 male guinea pigs. Both brief exposure pairing techniques and a group-living observation period were employed to test for disruption. During short-term testing sessions bulbectomized Ss courted females less than but mounted them as frequently as controls. While the groups did not differ in fighting behavior during short-term tests, controls scent-marked more frequently. Subsequently, Ss were observed as same-treatment pairs living continuously with females, and behavior was sampled over a 3-wk period. Under these conditions bulbectomized males, unlike controls, failed to form dominance orders, exhibited virtually no intermale aggressive activity, had markedly depressed sexual activity, and scent-marked rarely. It is concluded that olfactory bulbectomy profoundly alters the behavior of male domestic guinea pigs and that those alterations are most evident when experimental Ss are observed in a species-typical group-living environment. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cerebral effects of differential experience in hypophysectomized rats.

Examined whether the effects of enriched and impoverished environments on brain chemistry and weights in rats may be mediated hormonally. 3 experiments were done on 78 male Fischer and Long-Evans rats hypophysectomized at about 30 days and on normal controls. Environmental treatments lasted about 35-65 days of age. Among operates as among controls the enriched-environment Ss showed significantly greater cortical weight, decreased cortical acetylcholinesterase (AChE)/weight, and increased cholinesterase (ChE)/AChE. Thus these effects of differential environment do not require mediation by hormones of the pituitary or those regulated by the pituitary. Hypophysectomized Ss had significantly lower brain weights, lower cortical AChE/weight, and greater cortical ChE/AChE than did controls. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A selective attention deficit in the rat following induced dopamine receptor supersensitivity.

In the blocking paradigm, prior training to 1 conditioned stimulus (CSA) blocks the ability to attend to a 2nd conditioned stimulus (CSB) when the 2 form a compound (CSAB) in subsequent training. Blocking is an associative process by which animals learn to ignore CSB because it contains no new information regarding the reinforcing event. In Exp I, dopamine (DA) receptor supersensitivity was induced in 20 male Sprague-Dawley rats by prolonged pretreatment (21 days) with haloperidol (0.5 mg/kg). 20 control Ss received saline injections for 21 days. Results show that Ss with DA receptor supersensitivity failed to show blocking by responding equivalently to both elements of the CSAB compound (tone and light). This effect was replicated in Exp II, which also tested for an arousal interpretation of disrupted blocking by introducing a novel stimulus following training. 10 male Sprague-Dawley rats were randomly assigned to either saline or haloperidol pretreatment groups, and following 21 days of treatment and a 7-day drug free period, Ss were run in the 3-stage blocking procedure used in Exp I over 2 days. Findings indicate that supersensitive Ss were no more responsive to the novel stimulus than were controls, which supports a selective attention deficit interpretation of disrupted blocking with DA receptor supersensitivity. It is suggested that this attentional deficit resembles behavioral perseverations induced by DA agonists. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visibility of the intrapericardiac segment of the ascending aorta on conventional lateral chest films

The effect of intravitreally injected colchicine (100 mug and 300 mug) and vinblastine (100 mug) on function and sensitivity of the cat iris was studied in vivo. Both antimitotics caused the same effects: The sensitivity to touch of the cornea disappeared after the third day. The normal sensitivity recovered, but after 1 month there was still an anesthetic island in the center of the cornea. The consensual light reflex from the injected to the normal eye declined markedly between 12 and 24 h and was abolished after 4 days. The consensual light reflex from the normal to the injected eye decreased with a similar time course and was completely abolished or strongly reduced after 4-5 days. The function of the sphincter pupillae in the injected eye was reestablished after one month. The affected iris became supersensitive to both pilocarpine and norepinephrine. The degree of supersensitivity in the cholinergic system was closely and inversely related to the degree of impaired function. The function of the dilatator pupillae could not be tested. The observed phenomena were most likely due to inhibition of exoplasmic flow in the nerves supplying the iris and cornea.