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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Odors are inhaled through the nostrils into two segregated nasal passages and detected by sensory neurons in the bilateral olfactory epithelia. Airflow through the two nasal passages is usually asymmetrical because of alternating changes in nasal mucosal congestion. Here we show that neurons in the anterior olfactory nucleus (AON) of the adult rat olfactory cortex are ordinarily dominated by ipsi-nasal inputs and that binasal neurons in the AON respond to ipsilateral and contralateral nasal inputs with nearly equivalent odorant category selectivity. Deprivation of ipsilateral nasal inputs by unilateral nostril obstruction greatly enhanced the response to contralateral odor stimulation, in a reversible manner, in approximately 33% of AON neurons within only several minutes. In 27% of AON neurons that showed spike responses induced by the inspiration of room air, ipsilateral nasal obstruction initially suppressed respiration phase-locked spike discharges and, several minutes later, induced respiration phase-locked discharges with longer delays between inspiration and response. Recordings from AON neurons in rats with anterior commissure (AC) transection indicated that the resumed respiration phase-locked discharges with longer delays were mediated by the contralateral pathway via the AC. The ipsi-nasal occlusion-induced switching of nasal inputs to individual AON neurons shows that a subset of AON neurons in the adult rat has neuronal mechanisms for rapid nostril dominance plasticity, which may enable both right and left olfactory cortices to preserve their responsiveness to the external odor world, despite reciprocal changes in nasal airflow.
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PMID:Compensatory rapid switching of binasal inputs in the olfactory cortex. 1900 64

To investigate the morphological changes of accessory olfactory bulb (AOB) neurons arising from pheromonal signals, a coculture system of AOB neurons and vomeronasal (VN) neurons had been established. Our previous study indicates that under coculture condition, the density of dendritic spines of an AOB neuron is less and the individual spine-head volume is larger than those under monoculture condition. In this study, to determine whether these differences in the dendrites of AOB neurons reflect the differences in synapse formation and synaptic properties, we observed these cultured cells by electron microscopy. Various synapses were observed under each culture condition. Synapses were classified on the basis of their postsynaptic structure and the size of postsynaptic density (PSD) was measured. Under the coculture condition with VN neurons, synapses on dendritic spines, which formed between AOB neurons, were observed frequently. In contrast, many synapses were formed on dendritic shafts under monoculture condition. The PSD of asymmetrical synapses on the spines under coculture condition was larger than that under monoculture condition. Moreover, some dendrodendritic reciprocal synapses were found only in coculture. We confirmed synapse formation between VN axons and AOB dendrites by immunohistochemical electron microscopy; thus, the characteristics of synapses between AOB neurons are considered to be modified by the synaptic contacts with VN axons.
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PMID:Vomeronasal neurons promote synaptic formation on dendritic spines but not dendritic shafts in primary culture of accessory olfactory bulb neurons. 1910 55

In biology, economics, and politics, distributive power is the key for understanding asymmetrical relationships and it can be obtained by force (dominance) or trading (leverage). Whenever males cannot use force, they largely depend on females for breeding opportunities and the balance of power tilts in favour of females. Thus, males are expected not only to compete within their sex-class but also to exchange services with the opposite sex. Does this mating market, described for humans and apes, apply also to prosimians, the most ancestral primate group? To answer the question, we studied a scent-oriented and gregarious lemur, Propithecus verreauxi (sifaka), showing female dominance, promiscuous mating, and seasonal breeding. We collected 57 copulations involving 8 males and 4 females in the wild (Berenty Reserve, South Madagascar), and data (all occurrences) on grooming, aggressions, and marking behaviour. We performed the analyses via exact Spearman and matrix correlations. Male mating priority rank correlated with the frequency of male countermarking over female scents but not with the proportion of fights won by males over females. Thus, males competed in an olfactory tournament more than in an arena of aggressive encounters. The copulation frequency correlated neither with the proportion of fights won by males nor with the frequency of male countermarking on female scents. Male-to-female grooming correlated with female-to-male grooming only during premating. Instead, in the mating period male-to-female grooming correlated with the copulation frequency. In short, the biological market underwent seasonal fluctuations, since males bargained grooming for sex in the mating days and grooming for itself in the premating period. Top scent-releasers gained mating priority (they mated first) and top groomers ensured a higher number of renewed copulations (they mated more). In conclusion, males maximize their reproduction probability by adopting a double tactic and by following market fluctuations.
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PMID:Mating first, mating more: biological market fluctuation in a wild prosimian. 1926 37

Sleep-like behavior has been studied in honeybees before, but the relationship between sleep and memory formation has not been explored. Here we describe a new approach to address the question if sleep in bees, like in other animals, improves memory consolidation. Restrained bees were observed by a web camera, and their antennal activities were used as indicators of sleep. We found that the bees sleep more during the dark phase of the day compared with the light phase. Sleep phases were characterized by two distinct patterns of antennal activities: symmetrical activity, more prominent during the dark phase; and asymmetrical activity, more common during the light phase. Sleep-deprived bees showed rebound the following day, confirming effective deprivation of sleep. After appetitive conditioning of the bees to various olfactory stimuli, we observed their sleep. Bees conditioned to odor with sugar reward showed lesser sleep compared with bees that were exposed to either reward alone or air alone. Next, we asked whether sleep deprivation affects memory consolidation. While sleep deprivation had no effect on retention scores after odor acquisition, retention for extinction learning was significantly reduced, indicating that consolidation of extinction memory but not acquisition memory was affected by sleep deprivation.
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PMID:Sleep deprivation affects extinction but not acquisition memory in honeybees. 1986 96

In many rodent species, such as Syrian hamsters, reproductive behavior requires neural integration of chemosensory information and steroid hormone cues. The medial amygdala (MA) processes both of these signals through anatomically distinct sub-regions; the anterior region (MeA) receives substantial chemosensory input, but contains few steroid receptor-labeled neurons, whereas the posterodorsal region (MePD) receives less chemosensory input, but contains a dense population of steroid receptors. Importantly, these sub-regions have considerable reciprocal connections, and the goal of this experiment was therefore to determine whether interactions between MeA and MePD are required for male hamsters' preference to investigate female over male odors. To functionally disconnect MeA and MePD, males received unilateral lesions of MeA and MePD within opposite brain hemispheres. Control males received either unilateral lesions of MeA and MePD within the same hemisphere or sham surgery. Odor preferences were measured using a 3-choice apparatus, which simultaneously presented female, male and clean odor stimuli; all tests were done under conditions that either prevented or allowed contact with the odor sources. Under non-contact conditions, males with asymmetrical lesions investigated female and male odors equally, whereas males in both control groups preferred to investigate female odors. Under contact conditions, all groups investigated female odors longer than male odors, although males with asymmetrical lesions displayed decreased investigation of female odors compared to sham males. These data suggest that MeA-MePD interactions are critical for processing primarily the volatile components of social odors and highlight the importance of input from the main olfactory system (MOS) to these nuclei in the regulation of reproductive behavior. More broadly, these results support the role of the MA in integrating chemosensory and hormone information, a process that may underlie social odor processing in a variety of behavioral contexts.
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PMID:Lesions that functionally disconnect the anterior and posterodorsal sub-regions of the medial amygdala eliminate opposite-sex odor preference in male Syrian hamsters (Mesocricetus auratus). 1993 56

Neuropeptides play a major role in the modulation of information processing in neural networks. Somatostatin, one of the most concentrated neuropeptides in the brain, is found in many sensory systems including the olfactory pathway. However, its cellular distribution in the mouse main olfactory bulb (MOB) is yet to be characterized. Here we show that approximately 95% of mouse bulbar somatostatin-immunoreactive (SRIF-ir) cells describe a homogeneous population of interneurons. These are restricted to the inner lamina of the external plexiform layer (iEPL) with dendritic field strictly confined to the region. iEPL SRIF-ir neurons share some morphological features of Van Gehuchten short-axon cells, and always express glutamic acid decarboxylase, calretinin, and vasoactive intestinal peptide. One-half of SRIF-ir neurons are parvalbumin-ir, revealing an atypical neurochemical profile when compared to SRIF-ir interneurons of other forebrain regions such as cortex or hippocampus. Somatostatin is also present in fibers and in a few sparse presumptive deep short-axon cells in the granule cell layer (GCL), which were previously reported in other mammalian species. The spatial distribution of somatostatin interneurons in the MOB iEPL clearly outlines the region where lateral dendrites of mitral cells interact with GCL inhibitory interneurons through dendrodendritic reciprocal synapses. Symmetrical and asymmetrical synaptic contacts occur between SRIF-ir dendrites and mitral cell dendrites. Such restricted localization of somatostatin interneurons and connectivity in the bulbar synaptic network strongly suggest that the peptide plays a functional role in the modulation of olfactory processing.
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PMID:Somatostatin interneurons delineate the inner part of the external plexiform layer in the mouse main olfactory bulb. 2039 54

Although the major mode of transmission for serotonin in the brain is volume transmission, previous anatomical studies have demonstrated that serotonergic axons do form synaptic contacts. The olfactory glomeruli of the olfactory bulb of mammals receive a strong serotonergic innervation from the dorsal and medial raphe nuclei. In the present report, we investigate the synaptic connectivity of these serotonergic axons in the glomerular neuropil of the rat olfactory bulb. Our study shows that serotonergic axons form asymmetrical synaptic contacts on dendrites within the glomerular neuropil. Analyzing the neurochemical nature of the synaptic targets, we have found that 55% of the synapses were on GABA-immunopositive profiles and 45% on GABA-immunonegative profiles. These data indicate that barely half of the contacts were found in GABA-immunonegative profiles and half of the synapses in GABA-positive dendrites belonging to type 1 periglomerular cells. Synaptic contacts from serotonergic axons on dendrites of principal cells cannot be excluded, since some of the GABA-immunonegative postsynaptic profiles contacted by serotonergic axons had the typical ultrastructural features of bulbar principal cell dendrites. Altogether, our results suggest a complex action of the serotonergic system in the modulation of the bulbar circuitry.
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PMID:Synaptic connectivity of serotonergic axons in the olfactory glomeruli of the rat olfactory bulb. 2049 30

The mushroom body structure is progressively more complicated within the superfamily Scarabaeoidea. In the basal families and coprophagous Scarabaeidae, the calyx region is asymmetrical and poorly developed but reaches the maximal degree of development in the phytophagous Scarabaeidae of the subfamilies Melolonthinae and Cetoniinae. These Scarabaeidae have two separate calyces; moreover, some species have additional regions of glomerular neuropile. The processes of different Kenyon cell types segregate into special subdivisions of vertical and medial lobes. It is assumed that a progressive development of the mushroom body in phytophagous Scarabaeidae is associated with the need to integrate olfactory and visual information.
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PMID:[Structure of the mushroom bodies in Scarabaeoidea (Coleoptera): II. Phytophagous Scarabaeidae and general discussion]. 2126 67

Brain and behavioural lateralization at the population level has been recently hypothesized to have evolved under social selective pressures as a strategy to optimize coordination among asymmetrical individuals. Evidence for this hypothesis have been collected in Hymenoptera: eusocial honey bees showed olfactory lateralization at the population level, whereas solitary mason bees only showed individual-level olfactory lateralization. Here we investigated lateralization of odour detection and learning in the bumble bee, Bombus terrestris L., an annual eusocial species of Hymenoptera. By training bumble bees on the proboscis extension reflex paradigm with only one antenna in use, we provided the very first evidence of asymmetrical performance favouring the right antenna in responding to learned odours in this species. Electroantennographic responses did not reveal significant antennal asymmetries in odour detection, whereas morphological counting of olfactory sensilla showed a predominance in the number of olfactory sensilla trichodea type A in the right antenna. The occurrence of a population level asymmetry in olfactory learning of bumble bee provides new information on the relationship between social behaviour and the evolution of population-level asymmetries in animals.
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PMID:Lateralization in the invertebrate brain: left-right asymmetry of olfaction in bumble bee, Bombus terrestris. 2155 50

Behavioural and brain left-right asymmetries are a common feature among the animal kingdom. Lateralization often manifests itself at the population-level with most individuals showing the same direction of lateral bias. Theoretical model based on evolutionary stable strategy predicts that lateralization at the population-level is more likely to characterize social rather than solitary species. Empirical data supporting this hypothesis has been recently obtained in Hymenoptera showing that eusocial honeybees present an asymmetrical use of the antennae: the right antenna is involved in olfactory learning and present more olfactory receptors. However, no evidences about the role of antennal asymmetries in social interactions have been provided so far. Highly social ant species belonging to Formica rufa group are a good model for investigating natural communication because they are able to pass exact information to their nest mates. We applied the "binary tree" experimental paradigm, which allowed us to observe different types of antennal contacts performed by ants out of their nest. To examine possible asymmetrical use of the right and left antenna, we focused on "feeding" (the simplest) contacts where a "donor" ant is exchanging food with a "receiver" ant through trophallaxis. We observed a population-level asymmetry, with the "receiver" ant using the right antenna significantly more often than the left antenna. This study provides the first evidence of lateralization in antennal contacts in ants, and seems to support the hypothesis of mathematical models on the evolution of lateralization suggesting that the alignment of lateralization at the population-level matters in social interactions.
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PMID:Asymmetry in antennal contacts during trophallaxis in ants. 2248 89


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