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Results for “Olfactory Perception”

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PubMedDate not supplied

[Behavior of cats after unilateral section of the brachii of the inferior colliculi].

In experiments on 13 cats a unilateral section of the brachii of inferior colliculi produced a stable interhemispheric asymmetry not only in the auditory system, but in other (vestibular, visual, somatic, olfactory) analysers as well, which led to a disturbance of adequate space perception. This was manifested in orienting reactions directed only to the side of brain lesion. Animals were no more able to distinguish between the right and left troughs either by spatial or by modal cues. A complete "disregard" by the animals of the trough contralateral to the side of lesion suggests a hemispheric lateralization of conditioned connections providing for an adequate direction of the animals' running.

Animals↗
PubMed1975

Psychologic and neurologic consequences of partial and complete cerebral commissurotomy.

Preliminary psychologic testing was carried out on four patients who had undergone surgical sectioning of a portion or all of the corpus callosum and anterior commissure as a treatment for uncontrollable seizures. Results confirm earlier findings indicating the importance of the forebrain commissures in the interhemispheric exchange of a variety of sensory and motor information, and demonstrate that particular portions of the commissural system are responsible for transferring the information of specific sensory modalities. The patients also showed surprising abilities in performing complex tasks assumed to require integration of information from both hemispheres.

Adolescent↗
PubMed2026

Social evolution and diminished olfactory function in larval honey bees.

Social evolution made larval honey bees dependent on adult colony members for feeding; they are confined to cells in waxen honeycombs and visited about 100 times per day by adult "nurse" bees. Based on organismal resource conservation theory, we predicted larvae have diminished olfactory capabilities at both the molecular and behavioral levels. Consistent with theory, larvae expressed very low levels of Orco, an essential gene for olfactory receptor (OR) function. By contrast, they showed higher expression of Ir25a, essential for other forms of sensory perception including gustation. Also consistent with theory, behavioral assays demonstrated that larvae cannot find food via olfaction, suggesting they use taste for feeding. By contrast, it is known that adult honey bees use OR-based olfaction extensively for a variety of behavioral functions, and the honey bee genome contains many OR-encoding genes. Comparative transcriptomic analyses of social and nonsocial insects suggest that this developmentally regulated suppression of olfactory function is related to social evolution, especially systems of offspring care.

Animals↗
PubMed1992

Perception of breath components by the tropical bont tick, Amblyomma variegatum Fabricius (Ixodidae). I. CO2-excited and CO2-inhibited receptors.

Wall-pore olfactory sensilla located in the capsule of Haller's organ on the tarsus of Amblyomma variegatum ticks bear cells responding to vertebrate breath: one of these sensilla contains a CO2-excited receptor and a second sensillum has a CO2-inhibited receptor. Each of these antagonistic CO2-receptors, which display typical phasic-tonic responses, monitors a different CO2-concentration range. The CO2-inhibited receptor is very sensitive to small concentration changes between 0 and ca. 0.2%, but variations of 0.01% around ambient (ca. 0.04%) induce the strongest frequency modulation of this receptor. An increase of just 0.001-0.002% (10-20 ppm) above a zero CO2-level already inhibits this receptor. By contrast, the CO2-excited receptor is not so sensitive to small CO2 shifts around ambient, but best monitors changes in CO2 concentrations above 0.1%. This receptor is characterized by a steep dose-response curve and a fast inactivation even at high CO2-concentrations (greater than 2%). In a wind-tunnel, Amblyomma variegatum is activated from the resting state and attracted by CO2 concentrations of 0.04 to ca. 1%, which corresponds to the sensitivity range of its CO2-receptors. The task of perceiving the whole concentration range to which this tick is attracted would thus appear to be divided between two receptors, one sensitive to small changes around ambient and the other sensitive to the higher concentrations normally encountered when approaching a vertebrate host.

Animals↗
PubMed1977

Evaluation of intranasal zinc sulfate treatment on olfactory discrimination in rats.

The effects of intranasal syringing with 5% zinc sulfate were assessed in rats trained in a wind-tunnel olfactometer to detect the presence of an odor or to discriminate odors of graded intensities. The syringing produced a severe but brief interference in olfactory performance. Full recovery of detection performance occurred within 72 hr after treatment. Initial recovery of odor intensity discrimination occurred in 2-8 days and full recovery within 8-10 days. These results suggest that intranasal syringing with ZnSO4 is not an adequate control for the effects of anosmia produced by olfactory bulbectomy.

Administration, Intranasal↗
PubMedDate not supplied

[Evoked potentials in cortical and subcortical structures of the visual system to photic and acoustic stimuli under conditions of early light deprivation].

Rabbits raised during one month in the dark have exhibited a lower amplitude and longer peak latencies of evoked potentials (EP) to photic stimuli in the visual cortex and the lateral geniculate body with a simultaneous increase of amplitude and decrease of EP latencies in these formations to acoustic stimuli. Similar changes have been observed in the EP amplitude as well as unvaried latencies in the superior colliculus. An assumption has been made that under light deprivation monosensory units change after the type of function deficit, while polysensory ones, change after activity increase type. The later sets in as a result of compensatory processes due to enhanced activity from the receptors of other sensory systems (auditory, olfactory, somaestetic, and others).

Animals↗
PubMed1992

[Perception of odor quality by Free Image-Association Test].

A method was devised for evaluating odor quality. Subjects were requested to freely describe the images elicited by smelling odors. This test was named the "Free Image-Association Test (FIT)". The test was applied for 20 flavors of various foods, five odors from the standards of T&T olfactometer (Japanese standard olfactory test), butter of yak milk, and incense from Lamaism temples. The words for expressing imagery were analyzed by multidimensional scaling and cluster analysis. Seven clusters of odors were obtained. The feature of these clusters were quite similar to that of primary odors which have been suggested by previous studies. However, the clustering of odors can not be explained on the basis of the primary-odor theory, but the information processing theory originally proposed by Miller (1956). These results support the usefulness of the Free Image-Association Test for investigating odor perception based on the images associated with odors.

Adult↗
PubMed1978

Invariance of odor strength with sniff vigor: an olfactory analogue to size constancy.

Previous evidence has shown that detection threshold in humans and olfactory neural discharge rate in animal preparations both depend on flow rate of odorous vapor. But no data have been reported that show the effects of flow rate in humans on perceived odor strength at suprathreshold intensities. Subjects learned to inspire at two flow rates, one twice as great as the other, by adjusting (on a cathode ray tube) the transduced trace of a sniff-produced pressure change to match either of two target contours. They then made magnitude estimations of odor strength, while producing either weak or strong sniffs, for odorants presented over a wide range of concentrations via a specially designed sniff-bottle system. The odorant, diluted in diethyl phthalate, was n-butanol in two experiments and n-amyl acetate in two others. Subject-controlled flow rate had no effect on odor strength for either odorant. There was an apparent contradiction between these data and those on neural discharge rate that may, however, be resolved by adopting an odor constancy model: When sniff intensity varies during the olfactory exploration of an odor source, information about the rate at which odorant molecules are established at the receptor site is combined with information about sniff vigor so that the resulting percept is of invariant odor strength.

Acetates↗
PubMed1978

Models of the dynamics of neural populations.

Three requirements are posed for constructing models to simulate EEG dynamics. The element of the model should be an interactive ensemble of neurons and not single neurons. The observations must be statistical, such as EEG waves and averages of unit activity over time and over local neighborhoods containing neural subsets. The state variables and operations of the model must be clearly related to behavioral functions such as sensory reception and perception. A model is presented that exemplifies these requirements. Its key feature is the dependence of its levels of interaction on the level of its input, so that with each burst of input the model switches from an equilibrium state to a limit cycle state. A mechanism is described for coding sensory input into the spatial modulation of the limit cycle activity viewed as a carrier. It is suggested that sensory recepts and percepts exist at different hierarchical levels in the brain, recepts at the level of single neurones, and percepts at the level of neural ensembles, the latter being possibly manifested in the EEG.

Animals↗
PubMed1975

[The effect of peripheral stimulation on the electrical activity of the neocortex in chronic premesencephalic cats].

Chronic experiments were carried out with 19 adult cats. It is demonstrated that following a premesencephalic sectioning of the brain stem, with the lemniscal pathways being spared, on the second and third day after the surgery, auditory, olfactory and skin stimulations caused diffusive activation of the neocortex. Photic stimulation, though evoking responses in the visual cortex, was unable to desynchronize the neocortical electrical activity. Taking into account the data on the organization of hypothalamic afferent connections, it is suggested that diffuse activation of the neocortex in cats, when the mesencephalic reticular formation is completely excluded, occurs during auditory, olfactory and skin stimulations due to excitation of the posterior hypothalamus.

Animals↗
PubMed2026

Genetics of sensory nutrition.

Sensory nutrition is an emerging research area that examines how chemosensory perception, particularly taste and smell, shapes dietary behaviours, nutritional status, and disease risk. Variation in how individuals perceive the same foods may help explain differences in diet quality and responsiveness to behavioural dietary interventions, yet chemosensory phenotypes are rarely measured at the population level. Genetic variation contributes to this perceptual diversity and provides a framework for investigating sensory determinants of diet using genomic approaches. This review summarises evidence linking chemosensory genetics to perception and dietary behaviours, and discusses applications for causal inference and for precision and personalised nutrition. Twin studies reveal moderate to high heritability for bitter taste traits, with more modest and phenotype-dependent estimates for sweetness, sourness, saltiness, fat-related traits, and olfactory measures. Genome-wide association studies have identified loci in taste and olfactory receptor genes associated with specific chemosensory traits as well as liking and intake of various foods, although the evidence remains concentrated on bitter taste and populations of European ancestry. These genetic variants have been used in Mendelian randomisation, a genetics-based approach that strengthens causal inference, to test whether sensory traits influence dietary behaviour. For precision nutrition, evidence for taste genotype-stratified interventions remains limited and mixed. Realising the promise of sensory nutrition will require scalable and standardised chemosensory phenotyping, Findable, Accessible, Interoperable, and Reusable (FAIR) data infrastructure, expanded research in diverse populations, and integration with broader biological and sociocultural determinants of dietary intake.

Genetics↗