Effects of facial lobectomy on goldfish feeding behavior

The role of the facial lobe (FL) of goldfish in feeding behavior (search, pick up and ingestion) was investigated using the ablation method. Facial lobectomy (FLX) was performed on 10 fish, five of which were also fitted with blinders (BLs). It was found that FLX did not have any apparent effect on feeding behavior; however, this does not rule out some other, undetected and perhaps subtle, role of the FL in the feeding repertoire. A salient aspect of this finding was the observation that food pick up was not blocked, showing that the FL is not necessary for this feeding step. These results are contrary to that reported in catfish. This difference might be explained by the fact that the FLs of the two species are quite different anatomically; yet it does not account for the fact that the current results are at variance with the commonly accepted role of the teleostean FL as reflected in the literature. The use of BLs alone or combined with FLX also indicated no apparent involvement of the FL in feeding, as was able to be measured within the limitations of this investigation.     

Effects of stimulus female on sexual behavior of male rats given olfactory tubercle and corticomedial amygdaloid lesions

Lesions of the olfactory tubercle (OT) or corticomedial amygdala (CMA) damaging projections from the main or accessory olfactory bulbs, respectively, were made in male rats. When paired with ovariectomized females treated with estradiol benzoate (EB) and progesterone (Experiment 1) sexual behavior of lesioned males did not differ from sham and unoperated controls. During Experiment 2 males were paired with females chronically treated with EB only. Lesions of the OT did not affect mating while CMA lesions produced lengthened ejaculatory latencies (EL), longer mean interintromission intervals and more intromissions per ejaculation. Lesions of the CMA produced EL which were either within a normal range or noticeably extended with ejaculatory deficits becoming more exaggerated through three ejaculatory series. Low levels of soliciting by EB treated females seemed to precipitate ejaculatory deficits.     

Effects of forebrain lesions on spawning behaviour in the male goldfish

Lesions were stereotaxically placed in medial nuclei of the ventral telencephalon and preoptic area of male goldfish. Only lesions in the area ventralis telencephali pars supracommissuralis (Vs) and posterior pars ventralis (pVv) were effective in reducing the proportion of males spawning, as compared to sham groups, both 5 days (Experiment 1) and up to 4 weeks (Experiment 2) postoperatively. Spawning consistency over 7 weekly tests was negatively correlated with the volume of Vs-pVv destruction. Two-thirds of Vs-pVv lesioned males spawned on at least one of their weekly tests, with latencies for the onset of each courtship behaviour similar to those of control fish; partial performance of the spawning sequence was rare. These results suggest that lesion of the supracommissural telencephalon (Vs-pVv region) blocks the initiation of spawning behaviour in the male goldfish, perhaps by lowering reproductive motivation specifically or by interfering with the perception of sexual, particularly olfactory, cues.     

Tail pinch induces sexual behavior in olfactory bulbectomized male rats

Adult male Long-Evans rats were subjected to bilateral olfactory bulbectomy, sham surgery or no treatment. Of 34 bulbectomized rats, 24 failed to ejaculate on either of 2 tests with a primed ovariectomized female. All control animals exhibited normal sexual behavior, and 10 bulbectomized animals ejaculated at least once during the 2 tests. Later histological examination revealed a relationship between size of lesion and extent of behavioral deficits. After a third test, 16 nonejaculatory animals were subjected to a tail pinch (TP) procedure, immediately followed by a fourth test. The remaining 8 nonejaculatory animals were tested similarly, but without tail pinch. Ten of the 16 tail pinch animals showed complete sexual behavior on the first test, while 2 additional animals began to copulate after a second TP procedure 4 days later. Only 1 of the 8 animals not receiving TP ejaculated on these tests. Thus, TP applied shortly before sexual behavior tests can induce copulation in some males whose behavior had been disrupted by olfactory bulbectomy.     

The effects of olfactory system lesions and food deprivation on spontaneous behavior patterns of male hooded rats

The behavior of normal male rats was observed in an exploration field in which a number of olfactory cues were present. Locomotor activity, freezing, grooming, sniffing, rearing and boluses dropped were quantified over days and correlations between them were obtained. Following olfactory nerve sections at the bulb surface or total olfactory bulb and peduncle destruction, the measures were made again and lesion induced changes in them and olfactory cue exploration were noted. After a period of food deprivation, the measures were made a third time to assess possible motivational factors on the results. Both lesions and food deprivation altered many variables with the deeply lesioned animals more affected than the shallowly lesioned animals. Possible interactions between partial or complete anosmia and lesion induced changes in reactivity were considered. Some problems associated with the production of and tests for anosmia were also discussed.     

A battery of olfactory-based screens for phenotyping the social and sexual behaviors of mice

We provide a battery of screens that reflect the social and sexual behavior displayed by both captive and feral mice. Some screens focus on measuring aspects of chemical communication, providing information about whether or not mice will interact and if they do so, predict the nature of the interaction. Other screens measure direct interactions between target mice and same- and opposite-sex conspecifics, providing an indication of the social status and sexual responsiveness, respectively, of target mice. The battery of screens yields a high-throughput bioassay of a mouse's relative social status, competitive ability, social discrimination, and sexuality. These traits are essential elements of the socio-sexual behavior of mice as well as humans. Thus, by identifying phenotypic deviants for complex behaviors we will allow geneticists to map behavioral abnormalities onto specific chromosomes and increase the efficacy of genetically altered mice as models for human behavioral disorders.     

Effects of telencephalic ablation on shoaling behavior in goldfish

The role of the telencephalon in the shoaling behavior of the goldfish, Carassius auratus, was investigated. Experiments were carried out in a tank divided into three compartments. Subjects were introduced into the center compartment of the tank. In the activity phase, subjects swam alone, and swimming distance was used as an index of activity. In the shoaling behavior phase, a stimulus fish was introduced into one of the side compartments, and the time spent near the side compartment by the subject was used as index of shoaling behavior. After these measurements were made, visual and motor abilities were examined using the optomotor response. Subjects then received surgery and the same procedure was repeated. In Experiment 1, the effects of total ablation of the telencephalon and a section of the olfactory tract (OlT) were examined. The ablation group exhibited reduced activity and shoaling behavior compared with the sham and OlT group. In Experiment 2, the role of the dorsal part of the telencephalon was examined after damaging the dorsomedial and dorsolateral telencephalon. Lesions in either portion had no effect and no simple visual or motor deficits were seen. These results suggest that the ventral part of the telencephalon mediates shoaling behavior.     

Anterior olfactory nucleus or lateral olfactory tract destruction in rats and changes in appetitive and aversive behavior

Previous research with rats demonstrated a continuum of behavioral and biochemical effects following variable olfactory system damage. In general, increased removal of olfactory tissue along an antero-posterior axis amplified both behavioral and biochemical changes. The present experiments were undertaken to explore possible roles of the anterior olfactory nucleus (AON) and lateral olfactory tract (LOT) in the observed behavioral phenomena. Destruction of either structure decreased passive avoidance performance but selectively affected shuttle box avoidance performance; viz, AON destruction decreased it slightly whereas LOT destruction enhanced it. Animals with LOT destruction were also more emotional than AONs when handled and, when extensively lesioned, were more active in an open field than all other groups. In a bar pressing task for continuous reinforcement, AONs pressed significantly more than SHAMs during extinction although the LOT mean was also higher. When lesion size was correlated with the scores on several tests, AONs correlated positively with passive avoidance, shuttle box avoidance, and time to reach the extinction criterion in the bar pressing test while LOT lesions correlated negatively with shuttle box avoidance and bar press extinction time. The results were discussed against a background of other olfactory system lesions and some possible roles of the LOT and AON in reactivity to stimulation and responsiveness to reinforcement were considered. The close anatomical connections between the olfactory and limbic systems and similar behavioral changes after both limbic and olfactory lesions suggested a possible basis for the observed effects.     

Evidence that olfactory sensitivities to calcium and sodium are mediated by different mechanisms in the goldfish Carassius auratus

The current study investigated whether the olfactory sensitivity to Ca2+ and Na+ is mediated by the same mechanism in the goldfish, a freshwater teleost. The olfactory responses, as assessed by recording the electro-encephalogram (EEG) from the olfactory bulb, to changes in external [Ca2+] and to [Na+] were recorded in the absence and presence of increasing concentrations of the other ion. Low concentrations of Na+ (0-1.0mM) had no significant effects on the olfactory response to changes in [Ca2+] in terms of EC50, Imax or Hill co-efficient (n=8). A relatively high concentration of Na+ (10mM) significantly reduced the Imax and increased the EC50. One hundred millimolars Na+ reduced the olfactory response to Ca2+ to undetectable levels. Conversely, low concentrations of Ca2+ (0.1 and 1.0mM) significantly attenuated the olfactory response to changes in environmental [Na+], reducing the amplitude of response and increasing the threshold of detection (n=7). However, a high concentration of Ca2+ (10mM) failed to attenuate the olfactory response to Na+ completely. Taken together, these results suggest that, at normal environmental concentrations of these ions, Ca2+ and Na+ are detected by distinct and separate cellular mechanisms. However, there seems to be a degree of overlap between the two mechanisms. The exact mechanisms involved, and their biological roles, remain to be established.     

Sexual behavior elicited in cage-mates of olfactory tubercle stimulated rats

Fourteen male albino rats kept in pairs were implanted with bipolar electrodes in the olfactory tubercle. Electrical stimulation elicited a behavioral change in the cage-mates of the stimulated rats. This change consisted of increased exploratory activity in six animals. In three of these six rats, sexual behavior with mounting and pelvic thrusting was observed. The changes are described and discussed with special attention to sexual behavior.     

Effects of anterior hypothalamic lesions on the sexual behavior of prenatally-stressed male rats

Sprague-Dawley females were exposed to the stress of heat, restraint and bright lights during the third trimester of gestation. Virtually all male offspring tested for masculine sexual behavior as adults ejaculated and copulated with lure females. Also prenatally-stressed males exhibited two to three times as many lordotic responses as did males from nonstressed mothers. Because animals were crossfostered, an in utero action of prenatal stress is supported. Anterior hypothalamic (AHA) lesions significantly reduced the number of lordotic responses observed in prenatally-stressed male rats compared to those observed in prenatally-stressed males bearing sham lesions of the AHA. The possibility is presented that prenatal stress may influence the developing male brain.     

Sensory mediation of female-male mounting in the rat: I. Role of olfactory cues

Previous research has shown that olfactory cues mediate the mounting of female rats by male or other female rats. The present study examined whether olfactory cues might mediate the mounting of castrated, sexually inactive male rats by sexually receptive female rats (female-male mounting, or FMM). The effects of olfactory impairment, created by either olfactory bulbectomy (OBx) or olfactory occlusion (OOc), on FMM were investigated. Ovariectomized, hormone-primed female rats were given either OBx (OBx+) or sham (OBx-) surgeries. OBx+ females did not engage in any FMM after surgery, whereas sham-operated females continued to mount at baseline levels. This effect was replicated using OOc, a reversible form of olfactory impairment that involves the cannulation of the nasal cavity with a flexible tube. Females were either given the OOc surgery (OOc+), the OOc surgery with the tube removed immediately after placement (OOc-), or sham surgery in which the animal was only anesthetisized. OOc+ females, like OBx+ females, did not display FMM, whereas both control groups continued to mount at baseline levels. The effect of prior experience with FMM was also examined. Females were given either 0 or 5 encounters with castrated males prior to OBx+, OOc+, or OOc- surgeries. OBx+ and OOc+ females did not mount, regardless of prior mounting experience. These data indicate that the olfactory sense is a prime mediator of FMM, and that prior mounting experience does not offset the disruption of FMM caused by the elimination of olfactory cues.     

Changes in spontaneous,odor modulated and shock induced behavior patterns following discrete olfactory system lesions

Three groups of male hooded rats were preoperatively matched and then sham operated (SHAM), bilaterally lateral olfactory tract lesioned or anterior olfactory nucleus/anterior commissure lesioned. In one experiment, spontaneous behavior patterns emitted in an exploration field containing different odors were quantified during satiated and food deprived conditions. In other experiments, flinch and jump thresholds to electric shock and running patterns in an appetitively motivated straight alley experiment were measured. All lesioned animals were hyperactive and typically froze and groomed less than SHAMs while sniffing and rearing patterns differentiated the lesioned and SHAM groups in several ways. All animals had similar flinch and jump thresholds and also emitted similar types of responses to electric shock. In the straight alley, odors from normal and stressed rats had little effect on the running time of the experimental animals while a faint cat odor strongly inhibited SHAM running behavior. Responses to a novel chemical odor (trimethylpentane) and to changes in the alley floor or electric shock applied to the floor were minimal in all animals. The results were discussed against a background of other olfactory system lesions and some evidence separating the effects of olfactory cues from nonolfactory lesion effects was presented. Finally, problems associated with tests for olfactory discrimination were discussed. A need for more rigorous and specific discrimination tests in behavioral studies involving anosmia was emphasized.     

Temporal effects of discrete lesions in the olfactory and limbic systems on open-field behavior and dyadic encounters in male hooded rats

The spontaneous and dyadic behavior patterns of five matched groups of male hooded rats were compared to SHAMs following selective lesions of the olfactory and limbic system. One group received bilateral lateral olfactory tract lesions (LOT); a second bilateral anterior olfactory nucleus lesions (AON); a third sham operations (SHAM); a fourth bilateral AON and LOT lesions combined (ANLT); and a fifth cortico-medial amygdalar lesions (AMYG). When tested alone in the open field, LOT, ANLT, and, to some extent, AON lesioned animals were hyperactive. Activity scores for the AMYGs were not significantly different from that of the SHAMs. High rearing time scores were seen in the LOT, ANLT, and AMYG groups while high sniffing frequency and rearing frequency scores were associated with LOT and ANLT lesions. AONs had significantly higher and LOTs significantly lower sniffing time scores than any other groups. The AMYGs had the highest and LOTs the lowest sniffing bout lengths. Sniffing time for the ANLTs did not differ significantly from that of the SHAMs. Freezing was reduced in all lesioned groups as compared to SHAMs. These differences did not become clearly apparent until 7 to 10 days following surgery and were evident 40 days postsurgically. All lesioned animals were hyperirritable and difficult to handle following surgery with the LOTs, ANLTs, and AMYGs particularly so. This irritability was evident on the first day following surgery and persisted through postoperative day 40. When tested in pairs in a circular open field, all animals spent a large proportion of their time in direct contact. All lesioned animals, however, spent more time in aggressive interactions than did the SHAMs. The results were discussed against a background of other olfactory and limbic system lesions with particular reference to possible functional and anatomical substrates mediating behavioral changes typically reported following olfactory system lesions.     

The effects of cryogenic blockade of the centrifugal,bulbopetal pathways on the dynamic and static response characteristics of goldfish olfactory bulb mitral cells

Summary The responses of single goldfish olfactory bulb mitral cells were studied by extracellular recordings before and during cryogenic blockade of the efferent, centrifugal pathways in the ipsilateral olfactory tract. In each experiment the same odour was presented 40 times before and then 40 times during cooling. Each stimulus period (at least 30 s) was preceded by a stimulus-free interval (at least 30 s), during which a steady stream of tap water was applied. These procedures allow the investigation of activity changes of single neurons and of cell ensembles using statistical methods. i) In comparison with the pre-cooling activity, cooling of the efferent pathways did not cause a generalized disinhibition in mitral cell responses. Significant disinhibitory, significant inhibitory and indifferent effects occurred in about the same proportion during repetitive water and odour applications. ii) Abrupt or slow changes of single mitral cell discharge patterns during the 40 water and odour applications were observed before and during blocking of the efferent fibre systems: These pattern changes are therefore not necessarily a consequence of the efferent signals, and may thus have been a result of intrabulbar plasticity. iii) The most notable effect of efferent fibre blockade across all experiments was a significant (Wilcoxon-ranktest, P = 0.01) decrease of the signal to noise ratio i.e., the ratio between the activity during the spontaneous (water) and the stimulus (odour) phase, which could be demonstrated for both the phasic (immediately after stimulus onset) and tonic (during long term stimulation) components of the mitral cell responses.     

Effects of prepartal stress on postpartal nursing behavior, litter development and adult sexual behavior

Sprague-Dawley rats were exposed to the stress of restraint, heat and bright lights three times daily from Days 14 to 22 of gestation. Because prepartal stress did not markedly disturb the mother's retrieving and crouching behavior, disturbances in postpartal nursing behavior do not seem to account for the abnormal sexual behavior of male offspring as adults. The most significant finding was that litter weights were reduced, not only at birth, but for 3 weeks thereafter, suggesting that prepartal stress not only altered the pups in utero but also affected postpartal milk synthesis. The possibility emerges that prepartal stress may alter adult sexual behavior in males by modifications in fetal and/or maternal pituitary glands.     

Effects of chronic administration of caffeine and stress on feeding behavior of rats

Anorectic effects of caffeine are controversial in the literature, while stress and obesity are growing problems in our society. Since many stressed people are coffee drinkers, the objective of the present study was to evaluate the effect of stress and chronic administration of caffeine on feeding behavior and body weight in male and female rats. Wistar rats (both males and females) were divided into 3 groups: control (receiving water), caffeine 0.3 g/L and caffeine 1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated-restraint stress for 40 days). During the entire treatment, chow consumption was monitored and rats were weighed monthly. Afterwards, feeding behavior was evaluated during 3-min trials in food-deprived and ad libitum fed animals and also in repeated exposures, using palatable food (Froot Loops® and Cheetos®). Chronic administration of caffeine did not affect rat chow consumption or body weight gain, but diminished the consumption of both salty (Cheetos®) and sweet (Froot Loops®) palatable food. In the repeated trial tests, stress diminished savory snack consumption in the later exposures [I.S. Racotta, J. Leblanc, D. Richard The effect of caffeine on food intake in rats: involvement of corticotropin-releasing factor and the sympatho-adrenal system. Pharmacol Biochem Behav. 1994, 48:887-892; S.D. Comer, M. Haney, R.W. Foltin, M.W. Fischman Effects of caffeine withdrawal on humans living in a residential laboratory. Exp Clin Psychopharmacol. 1997, 5:399-403; A. Jessen, B. Buemann, S. Toubro, I.M. Skovgaard, A. Astrup The appetite-suppressant effect of nicotine is enhanced by caffeine. Diab Ob Metab. 2005, 7:327-333; J.M. Carney Effects of caffeine, theophylline and theobromine on scheduled controlled responding in rats. Br J Pharmacol. 1982, 75:451-454] and caffeine diminished consumption of both palatable foods (savory and sweet) during the early and later exposures. Most responses to caffeine were stronger in females, and stress exposure influenced the effect. Neither chronic caffeine nor stress affected adrenal weight and plasma corticosterone levels of the rats. These observations suggest that chronic caffeine consumption may have sex-specific effects on palatable food ingestion.     

Effects of olfactory bulb removal and flank shock on copulation in male rats

Sexually experienced male rats received bilateral olfactory bulbectomy (BOB, N=9), unilateral olfactory bulbectomy (UOB, N=7) or a sham operation (Sham, N=8). Copulation was severely disrupted in BOB males, whereas only minimal effects on copulation were observed in UOB males. Penile reflexes were not affected by either operation. Intermittent flank shock stimulated copulation in 5/6 BOB males. The BOB males that ejaculated had longer intromission latencies and longer postejaculatory intromission intervals than did Sham males receiving a similar schedule of shocks. Even so, all BOB males that ejaculated with flank shock also resumed copulation and ejaculated a second time without further shocks. Three BOB males that ejaculated with flank shock were tested the following week without shock, and none of these males copulated. These results strengthen previous conclusions that the olfactory bulbs are critical for the initiation and maintenance of sexual arousal in male rats.     

Effects of bilateral amygdaloid lesions on gonadal and pituitary hormones in serum and on sexual behavior in female rhesus monkeys

Bilateral lesions that destroyed the amygdaloid nuclear complex failed to alter either serum concentrations of luteinizing hormone (LH), estradiol (E2), progesterone, and testosterone or sexual behavior in female rhesus monkeys. In 3 of 5 females ovulation occurred in the postoperative cycle, and in 4 of 5 females exogenous E2 treatment released a surge of LH whose pattern was indistinguishable from the normal preovulatory surge. A postcastration rise in serum LH also occurred in the 5 lesioned monkeys, and E2 again induced an LH release. The data suggest that the amygdala does not play a major role in regulation of LH or ovarian steroid secretion during the menstrual cycle. Moreover amygdaloid lesions in female monkeys do not alter their sexual behavior.     

Blood supply of the olfactory nerve

Summary The authors report the results of a series of dissections and anatomic sections of the fronto-basal region of the brain and of the anterior cranial fossa in human cadavers. The constant presence of an arachnoidal cistern above the olfactory nerve was verified. The arachnoid separates from the pial membrane and forms a bridge with the ventral part of the olfactory bulb and tract, from the lateral edge of the olfactory sulcus to the medial edge of the gyrus rectus. The cistern is wide in its anterior portion, between the gyrus rectus and the olfactory bulb, and is reduced to a virtual slit in its posterior portion where the tract is lodged in the olfactory sulcus. The olfactory nerve can be separated without damaging fronto-basal arachnoidial adhesions over several centimeters. Dissection of this region after intravascular injection of colored media shows the constant presence of an artery destined to the olfactory bulb and tract. It originates either from the lateral surface of the anterior cerebral a. (segment A2), or from the medial fronto-basal a., and consistently provides terminal branches in front of the olfactory trigone in the medial olfactory sulcus. At their ventral extremity, the olfactory structures are therefore vascularised independently for several centimeters, from the lower face of the frontal lobe. The independent vascularisation of the olfactory nerve, the tenuous and easily detachable adhesions, and the actual presence of a true arachnoidal cistern all contribute to enabling surgical techniques which conserve olfactory function during anterior approaches.

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Vascularisation du nerf olfactif. Rapports méningés et applications chirurgicales

Résumé Les auteurs rapportent les résultats d'une série de dissections et de coupes de la région fronto-basale de l'encéphale et de la fosse crânienne antérieure sur sujets cadavériques. La présence constante d'une citerne arachnoïdienne au dessus du n. olfactif a été vérifiée. L'arachnoïde se sépare du feuillet pial et passe en pont à la partie ventrale du bulbe et du tractus olfactifs, du bord latéral du sillon olfactif au bord médial du gyrus rectus. La citerne est large dans sa portion antérieure, entre le gyrus rectus et le bulbe olfactif, se réduit à une fente virtuelle postérieure lorsque le tractus se loge dans le sillon olfactif. Le n. olfactif peut être séparé sans dommage des adhérences arachnoïdiennes fronto-basales sur quelques centimètres. La dissection de cette région, après injection intravasculaire de masses colorées montre, de façon originale, la présence constante d'une artère destinée au tractus et au bulbe olfactifs. Elle naît soit de la face latérale de l'a. cérébrale antérieure (segment A2), soit de l'a. fronto-basale médiale, pour donner ses branches terminales toujours en avant du trigone olfactif dans le sillon orbitaire médial. Sur quelques centimètres à leur extrémité ventrale, les structures olfactives ont donc une vascularisation indépendante de la face inférieure du lobe frontal. L'indépendance vasculaire du n. olfactif, des adhérences ténues, facilement détachables, et la réalité vérifiée d'une véritable citerne arachnoïdienne permettent d'imaginer des techniques conservatrices de la fonction olfactive utilisées dans plusieurs indications de la chirurgie de la fosse crânienne antérieure.