Browsing by Author "Chen, Jennifer"

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    Binaral Rivalry in the Presence of Visual Lexical and Perceptual Influences
    (2011) Chen, Jennifer; Basak, Chandramallika
    When two different odorants are presented at the same time to the two nostrils, we experience alternations in olfactory percepts, a phenomenon called binaral rivalry. Little, however, is known about the nature of such alternations. Here we investigate this issue by subjecting unstable and stable olfactory percepts to the influences of visual lexical or perceptual cues as participants engage in either mononaral sampling of a single odorant or binaral sampling oftwo different odorants. We show that alternations of olfactory percepts in the binaral setting persist even when visual modulation is present. We further show that while the two types of cues exert comparable effects in the mononaral setting, they produce greater and unequivocal differences in the binaral setting, with perceptual cues outweighing lexical cues. Our findings provide the evidence that an inherent, stimulus-driven process underlies binaral rivalry despite its general susceptibility to topdown influences.
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    Binaral Rivalry in the Presence of Visual Perceptual and Semantic Influences
    (Public Library of Science, 2012) Chen, Jennifer; Zhou, Wen; Chen, Denise
    When two different odorants are presented simultaneously to the two nostrils, we experience alternations in olfactory percepts, a phenomenon called binaral rivalry. Little is known about the nature of such alternations. Here we investigate this issue by subjecting unstable and stable olfactory percepts to the influences of visual perceptual or semantic cues as participants engage in simultaneous samplings of either two different odorants (binaral) or a single odorant and water (mononaral), one to each nostril. We show that alternations of olfactory percepts in the binaral setting persist in the presence of visual perceptual and semantic modulations. We also show that perceptual cues have a stronger effect than semantic cues in the binaral case, whereas their effects are comparable in the mononaral setting. Our findings provide evidence that an inherent, stimulus-driven process underlies binaral rivalry despite its general susceptibility to top-down influences.
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    Human Olfactory Perception: Characteristics, Mechanisms and Functions
    (2013-09-16) Chen, Jennifer; Pomerantz, James R.; Chen, Denise; Logan, Jessica M.
    Olfactory sensing is ubiquitous across animals and important for survival. Yet, its characteristics, mechanisms, and functions in humans remain not well understood. In this dissertation, I present four studies on human olfactory perception. Study I investigates the impact of short-term exposures to an odorant on long-term olfactory learning and habituation, while Study II examines human ability to localize smells; Study III probes visual-olfactory integration of object representations, and Study IV explores the role of olfaction in sensing nutrients. Several conclusions are drawn from these studies. First, brief intermittent exposures to even a barely detectable odorant lead to long-term incremental odorant-specific habituation. Second, humans localize smells based on gradient cues between the nostrils. Third, there is a within-hemispheric advantage in the integration of visual-olfactory object representations. Fourth, olfaction partakes in nutrient-sensing and facilitates the detection of food. Some broader implications of our findings are discussed.
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    Nostril-Specific Olfactory Modulation of Visual Perception in Binocular Rivalry
    (The Society for Neuroscience, 2012) Zhou, Wen; Zhang, Xiaomeng; Chen, Jennifer; Wang, Li; Chen, Denise
    It is known that olfaction and vision can work in tandem to represent object identities. What is yet unclear is the stage of the sensory processing hierarchy at which the two types of inputs converge. Here we study this issue through a well established visual phenomenon termed binocular rivalry. We show that smelling an odor from one nostril significantly enhances the dominance time of the congruent visual image in the contralateral visual field, relative to that in the ipsilateral visual field. Moreover, such lateralization-based enhancement extends to category selective regions so that when two images of words and human body, respectively, are engaged in rivalry in the central visual field, smelling natural human body odor from the right nostril increases the dominance time of the body image compared with smelling it from the left nostril. Semantic congruency alone failed to produce this effect in a similar setting. These results, taking advantage of the anatomical and functional lateralizations in the olfactory and visual systems, highlight the functional dissociation of the two nostrils and provide strong evidence for an object-based early convergence of olfactory and visual inputs in sensory representations.