Influence Of Olfaction Research Articles

Influence of Olfaction in Host-Selection Behavior of the Cassava Whitefly Bemisia tabaci

Cassava is a vital food-security crop in Sub-Saharan Africa. Cassava crops are, however, severely affected by viral diseases transmitted by members of the whitefly species complexBemisia tabaci. We have here investigated the role of olfaction in host selection behavior of the cassava whiteflyB. tabaciSSA-ESA biotype. Surprisingly, we find that the whiteflies appear to make little use of olfaction to find their favored host. The cassava whitely shows a highly reduced olfactory system, both at the morphological and molecular level. Whitefly antennae possess only 15 sensilla with possible olfactory function, and from the genome we identified just a handful of candidate chemoreceptors, including nine tuning odorant receptors, which would afford the whitefly with one of the smallest olfactomes identified from any insect to date. Behavioral experiments with host and non-host plants, as well as with identified specific volatiles from these sources, suggest that the few input channels present are primarily tuned toward the identification of unwanted features, rather than favored ones, a strategy quite unlike most other insects. The demonstrated repellence effect of specific volatile chemicals produced by certain plants unflavored by whiteflies suggests that intercropping with these plants could be a viable strategy to reduce whitefly infestations in cassava fields.

The olfactory stimulation slows down the substance clearance in the extracellular space of the hippocampus in rat brain

Accelerating the clearance of toxin in the brain extracellular space (ECS) has grown a promising strategy for treating some central nervous system diseases. As oldest sensory system, we know little about the influence of olfaction on the brain, but preclinical studies such as treatment of neurological diseases through it are in the ascendant. This makes it important to clarify the effects of olfaction on brain ECS and interstitial fluid (ISF) drainage. In this study, the effect of olfactory stimulation (eugenol, EUG) on ISF flow in hippocampus and its association with aquaporin 4 (Aqp4) had been investigated. The results show that eugenol can significantly increase the activity of hippocampal neurons, but reduce the clearance and diffusion rates of Gd-DTPA and A-594 in hippocampus. Similarly, eugenol inhalation slows down the rate of Gd-DTPA in CSF entering the hippocampus and its clearance. And knockout of Aqp4 gene aggravated these processes. In vitro results showed that after Aqp4 gene silencing, astrocytes grew slowly, with significantly decreased cells number, less nuclei, atrophied bodies and shorter processes. These results concluded that olfactory stimulation can change the ECS structure of the hippocampus, slow down the ISF drainage, and improve the function of neurons, while Aqp4 plays important roles.

Affective matching of odors and facial expressions in infants: shifting patterns between 3 and 7 months.

Recognition of emotional facial expressions is a crucial skill for adaptive behavior. Past research suggests that at 5 to 7 months of age, infants look longer to an unfamiliar dynamic angry/happy face which emotionally matches a vocal expression. This suggests that they can match stimulations of distinct modalities on their emotional content. In the present study, olfaction-vision matching abilities were assessed across different age groups (3, 5 and 7 months) using dynamic expressive faces (happy vs. disgusted) and distinct hedonic odor contexts (pleasant, unpleasant and control) in a visual-preference paradigm. At all ages the infants were biased toward the disgust faces. This visual bias reversed into a bias for smiling faces in the context of the pleasant odor context in the 3-month-old infants. In infants aged 5 and 7 months, no effect of the odor context appeared in the present conditions. This study highlights the role of the olfactory context in the modulation of visual behavior toward expressive faces in infants. The influence of olfaction took the form of a contingency effect in 3-month-old infants, but later evolved to vanish or to take another form that could not be evidenced in the present study.

Odours Influence Visually Induced Emotion: Behavior and Neuroimaging

The present study was conducted to investigate the influence of olfaction on subjective valence intensity ratings of visual presentations. Pictures of five different categories (baby, flower, erotic, fear and disgust) were presented each being associated with five different odour conditions [no odour, low and high concentrations of phenylethyl alcohol (positive odour) and low and high concentrations of hydrogen sulphide (negative odour)]. Study participants had to rate the emotional content of each picture with respect to valence and intensity while brain activities were recorded with a whole-cortex magnetoencephalograph (MEG). A significant interaction between odour condition and picture category with respect to rating performance was found. In particular, positive valence intensity ratings related to flowers were increased in positive and negative odour conditions. Negative valence intensity ratings related to disgusting pictures were also increased in positive and negative odour conditions. The only decrease was found in the baby category in the high concentration negative odour condition. No behavioural effects were found for the categories erotic and fear. Around 300 ms after stimulus onset odour-related brain activity effects were found for all picture categories. On the other hand, around 700 ms after stimulus onset odour-related brain activity effects occurred only in the flower, fear and disgust picture categories. We interpret that early information processing demonstrates more pronounced olfactory and visually induced emotion interaction than later information processing. Since the early time window more likely reflects subconscious information processing we interpret that interaction between olfaction and visually induced emotion mostly occurs below the level of consciousness. Later, rather conscious information processing, seems to be differently influenced by simultaneous olfaction depending on the kind of emotion elicited through the sense of vision.

Smelling odors, understanding actions

Previous evidence indicates that we understand others' actions not only by perceiving their visual features but also by their sound. This raises the possibility that brain regions responsible for action understanding respond to cues coming from different sensory modalities. Yet no studies, to date, have examined if this extends to olfaction. Here we addressed this issue by using functional magnetic resonance imaging. We searched for brain activity related to the observation of an action executed towards an object that was smelled rather than seen. The results show that temporal, parietal, and frontal areas were activated when individuals observed a hand grasping a smelled object. This activity differed from that evoked during the observation of a mimed grasp. Furthermore, superadditive activity was revealed when the action target-object was both seen and smelled. Together these findings indicate the influence of olfaction on action understanding and its contribution to multimodal action representations.

Psychophysical methods in the study of olfaction and respiratory tract irritation.

This article describes the fundamentals of olfaction and irritation perception and the dominant psychophysical methods for the assessment of olfaction and respiratory tract irritation. It also discusses factors that determine the olfactory and irritant response (ranging from the physicochemical properties of the stimulus to the physiological and cognitive characteristics of the individual). Because the vast majority of volatile chemicals stimulate the olfactory system at concentrations well below that at which they will elicit trigeminal activation, the evaluation of irritation from volatiles is often confounded by the perception of odor. Several methods have been used for studying the perception of irritation, without the influence of olfaction. The perception and reports of acute adverse effects of odor, annoyance, and irritation from volatile chemicals have multiple determinants. Understanding the perceptual impact of chemicals under environmentally realistic conditions requires attending to both the sensory and the psychological impact of those exposures. The review, which is largely based on presentations given by Dr. Richard Doty and Dr. William Cain, concludes by discussing the importance of the psychophysical approach, which considers physiochemical, subject, experimental, and cognitive/ psychological factors, for research in the chemical senses.

The Influence of Olfaction on Potentiation and Inhibition of Ultrasonic Vocalization of Rat Pups

Twelve-day-old isolated rat pups reduce their rates of ultrasonic vocalization (USV) when an anesthetized adult is placed into the test cage, whether the adult is their dam or an unfamiliar male. USV rates remain very low even after removal of the male (inhibition). However, after removal of the dam, pups greatly increase their rates of USV over their first isolation period (potentiation). USV potentiation can be induced by either an awake, normally behaving dam or by one that is anesthetized. To test the role of olfaction in inhibition and potentiation, PND12 pups were rendered anosmic via intranasal infusion of 5% zinc sulphate (ZnSO 4). Control pups were infused with normal saline. After overnight separation from the dam, the USV and other behaviors of pups were recorded during a 6-min test. Each pup was tested during an initial isolation period and a final isolation period. In the first experiment, an anesthetized adult (dam or unfamiliar male) or no companion was placed in contact with the pup during the middle minute. Anosmia prevented both potentiation and inhibition of USV by passive adult contact. Thus, it seems likely that pups use olfactory discrimination as the basis for these two highly differentiated vocal responses to social stimuli. Results from two additional experiments demonstrate that anosmia does not prevent potentiation when the adult dam is active and interacting with the pup on either postnatal day 12 or 8.

Maternal Aggression in Rats: Effects of Olfactory Bulbectomy, ZnSO4-Induced Anosmia, and Vomeronasal Organ Removal

Previous studies from our laboratory indicate that somatosensory inputs to the snout and ventral trunk, but not visual or auditory stimuli, play critical roles in the elicitation and maintenance of maternal aggression by lactating Norway rats toward a strange male intruder. There are conflicting reports on the influence of olfaction on maternal aggression. We explored the possible roles of central or peripheral anosmia on maternal aggression in Long–Evans rats during early lactation. In Experiment 1, responsiveness to both volatile and non-volatile odors was eliminated by bilateral olfactory bulbectomy (BOB), carried out during mid-gestation. BOB resulted in a reduced likelihood and intensity of maternal aggression on days 1 and 5 of lactation (L1 and L5), but also severe deficiencies in maternal behavior and litter growth and survival. In Experiment 2, anosmia to volatile odors was induced by spraying zinc sulfate intranasally on gestation day 21 and L1. This treatment had little or no effect on maternal aggression on L1 or L2 or on maternal behavior, especially if there was a 1-day recovery between the second treatment and testing. In Experiment 3, responsiveness to non-volatile odors was eliminated by vomeronasal-organ removal (VNX) carried out prior to mating. VNX did not disturb maternal behavior on L2–L8 or maternal aggression on L1 or L5. These results and others suggest that the expression of maternal aggression is affected by volatile odors, mediated possibly by accessory chemosensory systems such as the septal organ, or by neural changes that follow olfactory deafferentation, or both.

Involvement of various senses in responses to individual housing in laboratory albino mice: 1.The olfactory sense

Abstract ‘Isolation’ of male mice is much used to induce aggressiveness but, as practised in most laboratories, does not preclude communication between neighbouring conspecifics. This study examines the influence of olfaction on individual housing-induced social conflict between male laboratory mice. Attempts were made both to eliminate and to intensify the exposure to presumably socially meaningful odours. First, the effects of acute and chronic anosmia induced by application of four per cent zinc sulphate solution to the nostrils were determined in mice from a range of ages and social experiences. Secondly, the influences on the subsequent aggressiveness of the individually-housed male mice were estimated after introducing into their cages odoriferous bedding from groups of male and of female conspecifics. Both acute and chronic anosmia depressed the attacks directed towards ‘standard opponents’; indeed the chronic treatment virtually abolished this behaviour. Adding odoriferous bedding from the cages o...

The influence of olfaction on sexual behavior in the male golden hamster (Mesocricetus auratus).

AbstractAblation of the olfactory bulbs terminates the sexually oriented behavior patterns shown by the male hamster towards the female. All aspects of overt copulatory behavior including mounting are immediately eliminated. Investigatory behavior is decreased significantly and orientation of attention to the hindquarters of the animal being investigated (sexual orientation) is lost over a one to two week interval. This disruption of sexually oriented behavior patterns occurs regardless of the degree of experience of the male in mating prior to the bulbectomy. Unilateral bulbectomy or sham bulbectomy does not disrupt, even temporarily, the mating pattern.Evidence that the lack of mating behavior following bulbectomy is indeed due to anosmia was provided by rendering animals temporarily anosmic by use of zinc sulfate in the nasal cavities. Full recovery of sexual activity occurred within four to six days following this treatment. A second treatment produced a similar result.Naive males, raised in isolation, can show a normal copulatory pattern on first exposure to a receptive female. Naive males do not distinguish between diestrus (non receptive) and estrus (receptive) vaginal secretions from the female.The release of sexual arousal requires olfactory input in the male hamster, conditioning to other cues does not occur. However, differentiation between receptive and non‐receptive females appears to be a positive learned response. The absolute dependence of the male hamster on olfactory cues for sexual arousal has an obvious adaptive value in a species where the female tends to be dominant in encounters and the male, if unable to escape, can be maimed or killed during the course of a fight.