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Cells, Tissues, Organs 2017Glycoconjugates in the olfactory system play critical roles in neuronal formation, and α1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity....
Glycoconjugates in the olfactory system play critical roles in neuronal formation, and α1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity. Histochemical findings of α1-2Fuc glycan in the mouse olfactory system detected using Ulex europaeus agglutinin-I (UEA-I) vary. This study histochemically assessed the main olfactory and vomeronasal pathways in male and female ICR and C57BL/6J mice aged 3-4 months using UEA-I. Ulex europaeus agglutinin-I reacted with most receptor cells arranged mainly at the basal region of the olfactory epithelium. The olfactory nerve layer and glomerular layer of the main olfactory bulb were speckled with positive UEA-I staining, and positive fibers were scattered from the glomerular to the internal plexiform layer. The lateral olfactory tract and rostral migratory stream were also positive for UEA-I. We identified superficial short-axon cells, interneurons of the external plexiform layer, external, middle and internal tufted cells, mitral cells and granule cells as the origins of the UEA-I-positive fibers in the main olfactory bulb. The anterior olfactory nucleus, anterior piriform cortex and olfactory tubercle were negative for UEA-I. Most receptor cells in the vomeronasal epithelium and most glomeruli of the accessory olfactory bulb were positive for UEA-I. Our findings indicated that α1-2Fuc glycan is located within the primary and secondary, but not the ternary, pathways of the main olfactory system, in local circuits of the main olfactory bulb and within the primary, but not secondary, pathway of the vomeronasal system.
Topics: Animals; Female; Fucose; Male; Mice, Inbred C57BL; Mice, Inbred ICR; Olfactory Bulb; Olfactory Mucosa; Olfactory Pathways; Plant Lectins; Polysaccharides; Vomeronasal Organ
PubMed: 27423908
DOI: 10.1159/000447009 -
The Journal of Nutrition May 2021A low-protein diet can induce compensatory intake of excess energy. This must be better evaluated to anticipate the obesogenic risk that may result from the dietary...
BACKGROUND
A low-protein diet can induce compensatory intake of excess energy. This must be better evaluated to anticipate the obesogenic risk that may result from the dietary recommendations for reducing animal protein consumption.
OBJECTIVES
We aimed to further characterize the behavioral and physiological responses to a reduction in dietary protein and to identify the determinants of protein appetite.
METHODS
Thirty-two male Wistar rats [4 wk old, (mean ± SEM) 135 ± 32 g body weight] were fed a low-protein (LP; 6% energy value) or normal-protein (NP; 20%) diet for 8 wk. Food intake and body mass were measured during the entire intervention. During self-selection sessions after 4 wk of experimental diets, we evaluated rat food preference between LP, NP, or high-protein (HP; 55%) pellets. At the end of the experiment, we assessed their hedonic response [ultrasonic vocalizations (USVs)] and c-Fos neuronal activation in the olfactory tubercle and nucleus accumbens (NAcc) associated with an LP or HP meal.
RESULTS
Rats fed an LP diet had greater food intake (24%), body weight (5%), and visceral adiposity (30%) than NP rats. All LP rats and half of the NP rats showed a nearly exclusive preference for HP pellets during self-selection sessions, whereas the other half of the NP rats showed no preference. This suggests that the appetite for proteins is driven not only by a low protein status but also by individual traits in NP rats. LP or HP meal induced similar USV emission and similar neuronal activation in the NAcc in feed-deprived LP and NP rats, showing no specific response linked to protein appetite.
CONCLUSIONS
Protein appetite in rats is driven by low protein status or individual preferences in rats receiving adequate protein amounts. This must be considered and further analyzed, in the context of current recommendations for protein intake reduction.
Topics: Adiposity; Animals; Appetite; Body Weight; Diet, Protein-Restricted; Dietary Proteins; Eating; Energy Intake; Food Preferences; Intra-Abdominal Fat; Male; Meat; Nucleus Accumbens; Obesity; Olfactory Tubercle; Phenotype; Rats, Wistar; Rats
PubMed: 33693927
DOI: 10.1093/jn/nxaa455 -
Brain Research Jul 2014Rats selectively bred for high- and low-capacity for running on a treadmill (HCR; LCR) also differ in wheel-running behavior, but whether wheel-running can be explained...
UNLABELLED
Rats selectively bred for high- and low-capacity for running on a treadmill (HCR; LCR) also differ in wheel-running behavior, but whether wheel-running can be explained by intrinsic or adaptive brain mechanisms is not as yet understood. It is established that motivation of locomotory behavior is driven by dopaminergic transmission in mesolimbic and mesostriatal systems. However, whether voluntary wheel running is associated with enkephalinergic activity in the ventral striatum is not known.
MATERIALS AND METHODS
40 male (20 HCR and 20 LCR) and 40 female (20 HCR and 20 LCR) rats were randomly assigned to 3 weeks of activity wheel exposure or sedentary conditions without wheel access. After 3 weeks of activity-wheel running, rats were decapitated and brains were extracted. Coronal sections were analyzed utilizing in situ hybridization histochemistry for enkephalin (ENK) mRNA in the ventral striatum.
RESULTS
HCR rats expressed less ENK than LCR rats in the nucleus accumbens among females (p<0.01) and in the olfactory tubercle among both females (p<0.05) and males (p<0.05). There was no effect of wheel running on ENK mRNA expression.
CONCLUSION
Line differences in ENK expression in the olfactory tubercle, and possibly the nucleus accumbens, partly explain divergent wheel-running behavior. The lower striatal ENK in the HCR line is consistent with enhanced dopaminergic tone, which may explain the increased motivation for wheel running observed in the HCR line.
Topics: Animals; Enkephalins; Female; Male; Motor Activity; Nucleus Accumbens; Olfactory Tubercle; RNA, Messenger; Rats; Running; Ventral Striatum
PubMed: 24842004
DOI: 10.1016/j.brainres.2014.05.014 -
Journal of Neurosurgery Sep 2018OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular...
OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels. METHODS The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci. RESULTS The insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the "anterior perforated substance region." The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core. CONCLUSIONS As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.
Topics: Basal Ganglia; Brain Mapping; Brain Stem; Caudate Nucleus; Cerebral Arteries; Cerebral Cortex; Cerebral Veins; Cerebrum; Dominance, Cerebral; Gray Matter; Humans; Microsurgery; Neural Pathways; Olfactory Tubercle; Thalamus; White Matter
PubMed: 29271710
DOI: 10.3171/2017.5.JNS162897 -
Journal of Neurochemistry Aug 2017Recent studies show that dense dopamine (DA) innervation from the ventral tegmental area to the olfactory tubercle (OT) may play an important role in processing...
Recent studies show that dense dopamine (DA) innervation from the ventral tegmental area to the olfactory tubercle (OT) may play an important role in processing multisensory information pertaining to arousal and reward, yet little is known about DA regulation in the OT. This is mainly due to the anatomical limitations of conventional methods of determining DA dynamics in small heterogeneous OT subregions located in the ventral most part of the brain. Additionally, there is increasing awareness that anteromedial and anterolateral subregions of the OT have distinct functional roles in natural and psychostimulant drug reinforcement as well as in regulating other types of behavioral responses, such as aversion. Here, we compared extracellular DA regulation (release and clearance) in three subregions (anteromedial, anterolateral, and posterior) of the OT of urethane-anesthetized rats, using in vivo fast-scan cyclic voltammetry following electrical stimulation of ventral tegmental area dopaminergic cell bodies. The neurochemical, anatomical, and pharmacological evidence confirmed that the major electrically evoked catecholamine in the OT was DA across both its anteroposterior and mediolateral extent. While both D2 autoreceptors and DA transporters play important roles in regulating DA evoked in OT subregions, DA in the anterolateral OT was regulated less by the D2 receptors when compared to other OT subregions. Comparing previous data from other DA rich ventral striatum regions, the slow DA clearance across the OT subregions may lead to a high extracellular DA concentration and contribute towards volume transmission. These differences in DA regulation in the terminals of OT subregions and other limbic structures will help us understand the neural regulatory mechanisms of DA in the OT, which may elucidate its distinct functional contribution in the ventral striatum towards mediating aversion, reward and addiction processes.
Topics: Animals; Autoreceptors; Corpus Striatum; Dopamine; Electric Stimulation; Extracellular Space; Male; Olfactory Tubercle; Rats, Sprague-Dawley; Receptors, Dopamine D2; Reward
PubMed: 28498499
DOI: 10.1111/jnc.14069 -
Frontiers in Behavioral Neuroscience 2019Olfaction induces adaptive motivated behaviors. Odors associated with food induce attractive behavior, whereas those associated with dangers induce aversive behavior. We...
Olfaction induces adaptive motivated behaviors. Odors associated with food induce attractive behavior, whereas those associated with dangers induce aversive behavior. We previously reported that learned odor-induced attractive and aversive behaviors accompany activation of the olfactory tubercle (OT) in a domain- and cell type-specific manner. Odor cues associated with a sugar reward induced attractive behavior and c-fos expression in the dopamine receptor D1-expressing neurons (D1 neurons) in the anteromedial OT. In contrast, odor cues associated with electrical shock induced aversive behavior and c-fos expression in the pamine receptor D2-expressing neurons (D2 neurons) in the anteromedial OT, as well as the D1 neurons in the lateral OT. Here, we investigated whether the D1 and D2 neurons in the anteromedial OT play distinct roles in attractive or aversive behaviors, using optogenetic stimulation and real-time place preference (RTPP) tests. Mice expressing ChETA (ChR2/E123T)-enhanced yellow fluorescent protein (EYFP) in the D1 neurons in the anteromedial OT spent a longer time in the photo-stimulation side of the place preference chamber than the control mice expressing EYFP. On the other hand, upon optogenetic stimulation of the D2 neurons in the anteromedial OT, the mice spent a shorter time in the photo-stimulation side than the control mice. Local neural activation in the anteromedial OT during the RTPP tests was confirmed by c-fos mRNA expression. These results suggest that the D1 and D2 neurons in the anteromedial OT play opposing roles in attractive and aversive behaviors, respectively.
PubMed: 30930757
DOI: 10.3389/fnbeh.2019.00050 -
Scientific Reports Sep 2018Mammals shift their feeding habits from mother's milk to environmental foods postnatally. While this weaning process accompanies the acquisition of attractive behaviour...
Mammals shift their feeding habits from mother's milk to environmental foods postnatally. While this weaning process accompanies the acquisition of attractive behaviour toward environmental foods, the underlying neural mechanism for the acquisition is poorly understood. We previously found that adult mouse olfactory tubercle (OT), which belongs to the olfactory cortex and ventral striatum, has functional domains that represent odour-induced motivated behaviours, and that c-fos induction occurs mainly in the anteromedial domain of OT following learned odour-induced food seeking behaviour. To address the question whether the anteromedial OT domain is involved in the postnatal acquisition of food seeking behaviour, we examined OT development during weaning of mice. Whereas at postnatal day 15 (P15), all mice were attracted to lactating mothers, P21 mice were more attracted to familiar food pellets. Mapping of c-fos induction during food seeking and eating behaviours showed that while c-fos activation was observed across wide OT domains at P15, the preferential activation of c-fos in the anteromedial domain occurred at P21 and later ages. These results indicate that preferential c-fos activation in the anteromedial OT domain occurred concomitantly with the acquisition of attractive behaviour toward food, which suggests the importance of this domain in the weaning process.
Topics: Animals; Appetitive Behavior; Feeding Behavior; Female; Lactation; Male; Mice, Inbred C57BL; Olfactory Tubercle; Proto-Oncogene Proteins c-fos; Weaning
PubMed: 30181622
DOI: 10.1038/s41598-018-31604-1 -
Journal of Neurophysiology Jan 2021The ventral striatum regulates motivated behaviors that are essential for survival. The ventral striatum contains both the nucleus accumbens (NAc), which is well...
The ventral striatum regulates motivated behaviors that are essential for survival. The ventral striatum contains both the nucleus accumbens (NAc), which is well established to contribute to motivated behavior, and the adjacent tubular striatum (TuS), which is poorly understood in this context. We reasoned that these ventral striatal subregions may be uniquely specialized in their neural representation of goal-directed behavior. To test this, we simultaneously examined TuS and NAc single-unit activity as male mice engaged in a sucrose self-administration task, which included extinction and cue-induced reinstatement sessions. Although background levels of activity were comparable between regions, more TuS neurons were recruited upon reward-taking, and among recruited neurons, TuS neurons displayed greater changes in their firing during reward-taking and extinction than those in the NAc. Conversely, NAc neurons displayed greater changes in their firing during cue-reinstated reward-seeking. Interestingly, at least in the context of this behavioral paradigm, TuS neural activity predicted reward-seeking, whereas NAc activity did not. Together, by directly comparing their dynamics in several behavioral contexts, this work reveals that the NAc and TuS ventral striatum subregions distinctly represent reward-taking and reward-seeking. The ventral striatum, considered the reward circuitry "hub," is composed of two regions: the NAc, which is well established for its role in reward processing, and the TuS, which has been largely excluded from such studies. This study provides a first step in directly contextualizing the TuS's activity in relation to that in the NAc and, by doing so, establishes a critical framework for future research seeking to better understand the brain basis for drug addiction.
Topics: Animals; Cues; Drug-Seeking Behavior; Goals; Male; Mice; Mice, Inbred C57BL; Neurons; Nucleus Accumbens; Reward
PubMed: 33174477
DOI: 10.1152/jn.00495.2020 -
World Neurosurgery Jan 2023Lesions in the ventral striatum region (above the anterior perforated substance) are a challenge for neurosurgeons due to their direct relationship with the... (Review)
Review
BACKGROUND
Lesions in the ventral striatum region (above the anterior perforated substance) are a challenge for neurosurgeons due to their direct relationship with the lenticulostriate arteries, which difficult the surgical access. The standard approaches for this region include the following: 1) transfrontal approach, 2) transanterior perforating substance approach, 3) transcallosal transventricular approach, and 4) pterional transsylvian-transinsular route. In this study, we aimed to describe a novel anatomical approach through the anterior limiting sulcus of the insula in order to access the ventral striatum.
METHODS
We reviewed the literature and performed a detailed dissection of this region by using Klingler's technique with brain specimens injected with silicone, paying special attention to the white fibers and lenticulostriate arteries, and provided a description of an illustrative case of a cavernous malformation.
RESULTS
Neuroanatomical dissections showed that the lenticulostriate arteries had an inverted C-shaped anterior concavity, leaving less significant vascular relationships in the depth of the anterior limiting sulcus of the insula. In the case we described, the cavernous malformation was completely resected and the patient was discharged without any neurological deficits.
CONCLUSIONS
The transanterior limiting sulcus of the insula approach to the ventral striatum offers a safe access route for selected cases and can be performed on the basis of anatomical references. Three-dimensional understanding of the intrinsic brain architecture and its relationships with vascular structures in this specific area is important and can be acquired mainly through laboratory training.
Topics: Humans; Neurosurgical Procedures; Insular Cortex; Olfactory Tubercle; Dissection; Middle Cerebral Artery
PubMed: 36208868
DOI: 10.1016/j.wneu.2022.09.115 -
Current Biology : CB Jul 2018Critical animal behaviors, especially among rodents, are guided by odors in remarkably well-coordinated manners, yet many extramodal sensory cues compete for cognitive...
Critical animal behaviors, especially among rodents, are guided by odors in remarkably well-coordinated manners, yet many extramodal sensory cues compete for cognitive resources in these ecological contexts. That rodents can engage in such odor-guided behaviors suggests that they can selectively attend to odors. Indeed, higher-order cognitive processes-such as learning, memory, decision making, and action selection-rely on the proper filtering of sensory cues based on their relative salience. We developed a behavioral paradigm to reveal that rats are capable of selectively attending to odors in the presence of competing extramodal stimuli. We found that this selective attention facilitates accurate odor-guided decisions, which become further strengthened with experience. Further, we uncovered that selective attention to odors adaptively sharpens their representation among neurons in the olfactory tubercle, an olfactory cortex region of the ventral striatum that is considered integral for evaluating sensory information in the context of motivated behaviors. Odor-directed selective attention exerts influences during moments of heightened odor anticipation and enhances odorant representation by increasing stimulus contrast in a signal-to-noise-type coding scheme. Together, these results reveal that rats engage selective attention to optimize olfactory outcomes. Further, our finding of attention-dependent coding in the olfactory tubercle challenges the notion that a thalamic relay is integral for the attentional control of sensory coding.
Topics: Animals; Attention; Decision Making; Male; Odorants; Olfactory Cortex; Olfactory Pathways; Olfactory Perception; Rats; Rats, Long-Evans; Smell
PubMed: 30056854
DOI: 10.1016/j.cub.2018.05.011