10:00
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Introduction: Addressing Gaps In Chemosensory Science:
Bridging The Divide To Improve Patient Outcome
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10:05
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Partnering For Progress: Laying The Foundation For Advancing Patient Partnerships In Chemosensory Research: Insights From A Pcori-Funded Patient Engagement Program |
10:20
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Panel Discussion: Experiences And Challenges In Partnering With Patients Throughout The Research To Translation Process |
12:50
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Discovery - What Would New Techniques And Methods Unlock For The Treatment Of Smell And Taste Dysfunction? |
1:20
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Clinician - Challenges And Opportunities? |
1:50
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Regulatory, Dissemination & Implementation |
5:30
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The Mind Of A Bee
Lars Chittka
University of London |
10:00
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Odor Quality Prediction: Cracking The Odor Code
Jessica H. Brann, Casey Trimmer
dsm-firmenich, New York, NY, United States
In the last two decades, extensive research efforts have focused on a fundamental problem: can we predict the odor quality of monomolecular odorants, and if so, can we extend this ability to predict the odor quality of a complex odor blend? To predict odor quality, some approaches unify perceptual observations with odorant physicochemical parameters, while others also incorporate ligand-receptor relationships. In this symposium, we discuss approaches to date, and address the question of how data describing stimulus integration in peripheral olfactory receptors and the olfactory bulb can be used to predict monomolecular odorant quality, and how that answer may change when considering quality prediction for natural odors and/or odorant mixtures. |
10:05
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Evidence For Elemental Olfactory Quality Encoding
Patrick Pfister
dsm-firmenich |
10:28
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Do Neurons Matter? Using Neural Recordings Of Odor Representations To Inform Predictive Models Of Odor Quality
Matt Wachowiak
Dept. of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, United States
Efforts to understand the relationship between odorant chemical structure and odor quality have made great progress in recent years, thanks in no small part to the power of machine learning approaches that couple chemoinformatics with olfactory psychophysics in humans. However, such approaches bypass a mechanistic understanding of odor perception and raise the question of whether understanding the neural mechanisms underlying olfactory sensation has anything to offer the odor quality prediction problem. I will review recent work from our laboratory in which we have characterized the odorant response specificities of a large fraction of the olfactory sensory neuron population in mice and explored the structural determinants of odorant receptor tuning in vivo. This work suggests that olfactory receptor specificities can be well-explained by straightforward chemical substructural features, but also that the determinants of tuning are heterogeneous across chemical space and across receptor subclasses. We have also found that perireceptor processes - in particular, the rapid metabolism of odorants in the olfactory mucosa - strongly shape the neuronal representation of odors in vivo and distort the apparent relationship between chemical structure and receptor specificity. I will discuss how these findings, arising from neuronal recordings in non-human animals, may lead to refined predictions and inform mechanistically-grounded models of odorant structure-quality relationships. |
10:51
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Predicting Human Olfactory Perception From Stimulus Chemistry
Emily J Mayhew
Michigan State University, East Lansing, MI, United States
A collection of hundreds of distinct molecules at concentrations spanning several orders of magnitude travel up our nasal cavities and activate some combination of several hundred olfactory receptors, which transmit signals to the brain, and in under a second, we’ve recognized the smell of coffee. How does the olfactory system translate such a chemically complex stimulus into odor perception, and can we learn to predict percept from stimulus chemistry? While receptor activation and cortical processing are essential for human olfactory coding, there are significant efficiencies in pursuing direct prediction of percept from chemistry. By leveraging odor-specific chemical features, odor characteristics for a single odorant can be predicted via a GNN model with reasonable accuracy (median R=0.49), representing an advance over previous models that used out-of-the-box chemical features. As the field sets its sights on odor mixture stimulus-to-perception modeling, there will be trade-offs in efficiency and diagnostic insights between consolidating or replicating individual steps in olfactory processing. This talk will discuss the state-of-the-art in chemistry-to-perception modeling and make the case for perception-to-perception modeling as an insight-rich strategy to advance odor mixture predictive models. |
11:14
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From Woody To Fruity: Leveraging Substructural Features For Odor Prediction Of Complex Mixtures
Doris Schicker1, Satnam Singh1,2, Jessica Freiherr1,2, Andreas Grasskamp1
1Department of Sensory Analytics and Technologies, Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany, 2Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
The odor of a molecule is foremost characterized by its molecular structure. We previously showed that using a well-defined set of substructural features is an effective strategy to predict the odor of single molecules. In nature, however, perceived odors are often the result of a complex mixture of odor-active molecules. Evaluating or predicting the scent quality of these mixtures poses a significant challenge, not just for statistical models but also for trained assessors. We recently demonstrated that machine learning algorithms are able to predict key odor attributes of whiskies (American or Scotch) based on their molecular composition and substructural features. This was achieved by integrating data from analyses of 16 whiskies with sensory data from 11 panelists and applying machine learning algorithms. We used the linear classifier OWSum and a Convolutional Neural Network (CNN) to classify samples and predict sensory scores with high accuracy, surpassing panel assessments and enabling fast data-driven sensory evaluation in mixtures. This approach has high potential in many applications to support sensory assessments and provide a predictive framework for quick sample classification. |
11:32
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Integrating Chemical, Sensory, And Expert Knowledge Data For Predicting Odor Profiles In Complex Mixtures
Thierry Thomas-Danguin
Centre des Sciences du Goût et de l'Alimentation, INRAE, CNRS, Institut Agro, Université Bourgogne Europe, Dijon, France
Odor quality arises from the initial detection of volatile chemical compounds by olfactory receptors. Consequently, knowing the chemical composition of an odor stimulus should theoretically lead to an understanding of its odor quality. However, numerous studies indicate that this relationship is rarely straightforward. The list of odorants in an odor stimulus is often insufficient to predict the perceived odor of their mixture. This is because odor perception relies on the olfactory system's processing of multiple odorants embedded in complex mixtures, where perceptual interactions occur and support configural odor mixture perception. As a result, predicting the perceptual outcome of complex odor mixtures remains a significant challenge. This presentation introduces an innovative modeling approach integrating odor-active compound stimulus composition with expert knowledge to predict the odor quality of mixtures containing dozens of odorants. The model incorporates three types of heterogeneous data: chemical data, sensory data, and expert knowledge from flavorists. Expert knowledge is structured through an ontology and formalized using fuzzy rules optimized by an evolutionary algorithm. The model combines information from the odorants with the fuzzy rules to predict the mixture's odor profile, including both odor quality and intensity. This model was successfully applied to red wines, where the odor profiles were predicted based on Gas-Chromatography-Olfactometry analyses of their composition. Overall, this presentation highlights novel approaches to understanding odor quality construction in complex odorant mixtures. This work was supported by the Agence Nationale de la Recherche (ANR-18-CE21-0006 MULTIMIX) and the Conseil Régional Bourgogne, Franche-Comté (PARI-2015). |
2:00
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Neuromodulation And Chemosensation: From Dynamics To Function
Natale Sciolino1, John Boughter2
1University of Connecticut, Storrs, CT, United States, 2University of Tennessee Health Sciences Center Memphis, Memphis, TN, United States
Neuromodulators are essential for shaping sensory information processing, and conversely salient sensory information regulates the dynamics of neuromodulatory systems. The activates and functions of neuromodulators have been historically difficult to study in vivo. Recent advancements in optical imaging, chemical sensors, and optogenetics have allowed scientists to better understand the interaction of neuromodulatory circuits and sensory systems. This symposium highlights cutting-edge tools that reveal how neuromodulators like acetylcholine, norepinephrine, dopamine, and neuropeptide Y influence taste and odor processing and how chemosensory information influences neuromodulatory signaling in both rodents and humans. These interactions between chemosensation and neuromodulation help organisms make appropriate feeding decisions and adjust their behavior based on physiological needs and external cues. |
2:05
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Neuromodulation In The Gustatory Cortex And Its Involvement In Taste Behaviors
Mia B. Fox1, Walt J. Krueger1, Stephanie M. Staszko2, John D. Boughter Jr.1, Max L. Fletcher1
1Department of Anatomy and Neurobiology, University of Tennessee Health Science Center , Memphis, TN, United States, 2Yale School of Medicine, Yale University, New Haven, CT, United States
The neuromodulator acetylcholine (ACh) is released in various cortical areas in association with functions such as novelty, learning, and attention. Previous studies show its release in gustatory cortex (GC) plays an important role in both taste neophobia and conditioned taste aversion (CTA) behaviors. We used neuronal tracing and immunocytochemistry to delineate cholinergic input to the GC from the basal forebrain (BF) in mice. 73% of GC-projecting neurons in BF were cholinergic, positive for choline acetyltransferase (ChAT). Immunocytochemistry revealed the presence of (muscarinic) M1 and M2 receptors in GC. Behavioral experiments with either systemically administered or direct cortical infusion of scopolamine (ACh antagonist) indicate that blocking muscarinic receptors does not affect the neophobic response to a novel stimulus, but it interferes with either attenuation of neophobia or expression of a conditioned taste aversion (CTA). We are currently conducting calcium imaging studies investigating the activity of cholinergic neurons during taste neophobia. GCaMP was expressed in, and microendoscopes implanted into, the BF of Chat-cre mice. Finally, simultaneous electrophysiological recordings of BF and GC demonstrate increased theta coherence between these structures that becomes more aligned to consumption with familiarity. |
2:28
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Locus Coeruleus Noradrenergic Modulation Of Cortical Taste Processing
Will Fan, Natale R. Sciolino
University of Connecticut, Storrs, CT, United States
Neuromodulatory systems adaptively regulate the computations performed by neural circuits, yet their involvement in central taste processing is largely unexplored. The primary gustatory cortex (GC) receives a prominent neuromodulatory input from noradrenergic neurons in the locus coeruleus (LC), which plays a well-established role in shaping sensory perception. LC neurons exhibit phasic firing in response to salient events and elevated tonic activity in stressed or high-arousal states. To investigate how phasic and tonic LC activity influences GC taste processing, we used miniscope calcium imaging to record taste-evoked responses of GC neurons while optogenetically activating LC axons using different stimulation patterns. We found that activation of LC axons produced heterogeneous changes in the response dynamics of a subset of GC neurons, reshaping their taste response profiles. Assessment of response sparseness, taste quality encoding, and palatability encoding revealed that LC’s modulatory effects depend on its activity pattern. Specifically, phasic LC output tended to enhance taste encoding, whereas elevated tonic LC output impaired it. These findings highlight the intricacy of neuromodulation in sensory systems and the flexibility of cortical taste processing, offering new insights into how behavioral states shape food perception. |
2:51
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Monoamine Dynamics In Response To Tastes In Humans
Alexandra DiFeliceantonio1,2
1Fraline Biomedical Resarch Institute, VTC, Roanoke, VA, United States, 2Department of Human Nutrition, Foods, and Exercise, Blacksburg, VA, United States
Attributing value to taste depends on the integration of central gustatory signals with reward-related computations. There is strong evidence that the amygdala is a site where such integration occurs. For example, the amygdala has strong reciprocal connections between primary gustatory cortex, gustatory thalamus, and brainstem. Functional evidence suggests that gustatory cortex in rodents projects to the amygdala. Further, human fMRI studies reliably report amygdala activation to taste stimuli, and lesions to the amygdala impair preferences for food cues in humans. While electrophysiological recordings from human amygdala reveal food-specific valuation encoding in a preference task, little is known about the neurochemical dynamics in this region that support these computations. Here we used a novel technology that allows neurochemical measurements on depth electrodes used during standard of care in epilepsy monitoring to measure dopamine (DA), norepinephrine (NE), and serotonin (SE) in the amygdala while people (n = 4) consumed beverages with varying amounts of fat and sugar. We found that DA, NE, and SE fluctuations differed by drink condition. Further analysis revealed that the difference between SE and NE fluctuations correlates with ratings. Collectively, these findings demonstrate our capacity to monitor sub-second monoamine signaling in the human amygdala during food intake and represent a first of their kind test of the translatability of key findings from animal models. |
3:14
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Dopamine Differentially Encodes Sucrose Across The Acquisition And Extinction Of A Conditioned Taste Aversion
Maxine K. Loh1,2, Samantha J. Hurh2, Paula Bazzino3, Rachel M. Donka2, Alexandra T. Keinath2, Jamie D. Roitman2, Mitchell F. Roitman2,3
1Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States, 2Department of Psychology, University of Illinois at Chicago, Chicago, IL, United States, 3Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, IL, United States
Mesolimbic dopamine encoding of non-contingent rewards and reward-predictive cues has been well established. Considerable debate remains over how mesolimbic dopamine responds to aversion in contrast to reward. Inconsistencies may arise from the use of aversive stimuli transduced along different neural paths relative to reward or the conflation of responses to avoidance and aversion. In rats, we measured behavioral and dopamine responses in vivo to the changing valence of intraoral sucrose via DeepLabCut and fiber photometry. Pairing sucrose tasting with malaise via injection of lithium chloride (LiCl) drove the development of a conditioned taste aversion (CTA) and rendered the typically rewarding taste of sucrose aversive upon subsequent re-exposure. Following CTA formation, intraoral sucrose suppressed phasic ventral tegmental area dopamine (VTADA) neuronal activity and nucleus accumbens dopamine release while increasing behavioral reactivity (nose and forepaw movement). This pattern of dopamine signaling and behavioral reactivity after CTA is similar to intraoral infusions of innately aversive quinine and contrasts with that to sucrose when it was novel or not paired with LiCl. Dopamine responses were negatively correlated with behavioral reactivity to intraoral sucrose and predicted home cage sucrose preference. Further, the strength of the CTA modulated phasic dopamine responses to sucrose, which were further suppressed by repeated LiCl pairings and recovered through extinction. Together, these findings demonstrate differential dopamine encoding of the same taste stimulus according to its valence, which is aligned to distinct behavioral responses. |
3:37
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A Thirst-Dependent Odor Spotlight
Silvia Huerta Lopez, Katie McShea, Stephen Liberles
Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA, USA, Boston, MA, United States
Internal states, such as hunger and thirst, are powerful motivational states that shape sensory perception, enhancing attention to need-relevant cues. Here, we investigate how thirst differentially influences odor perception, selectively heightening attraction to drink odors while sparing responses to other attractive cues, such as pheromones. The mouse olfactory system detects diverse odors that drive behaviorally specific responses, yet how distinct physiological states modulate sensory pathways to drive state-appropriate behaviors remains unclear. Our studies aim to uncover the molecular and circuit mechanisms by which thirst selectively modulates odor responses, providing insight into how internal states dynamically influence sensory processing and behavior. |
2:00
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Eating With Feeling: Exploring Connections Between Emotions And Chemosensory Stimuli
Kathryn Deibler1, Xiaorong (Phoebe) Su2, Casey Trimmer3, Dan Wesson4, Theresa White5
1Flavour Essentials, 3Firmenich, 4University of Florida, 5Le Moyne College
Understanding the interplay between emotions and chemosensory stimuli presents significant opportunities for industries focused on product development in food, fragrance, and other consumer goods. This presentation will explore the neurobiological and psychological foundations that link emotional processing with the chemical senses, specifically olfaction and gustation. Furthermore, advancements in the measurement of emotional responses to chemosensory stimuli, such as augmented reality, large language models, generative AI, and neuroimaging, will be examined in conjunction with traditional models such as psychophysics and electroencephalography (EEG), highlighting potential multi-component approaches to innovative product applications.
This discussion will focus on practical insights for industry professionals, emphasizing how a deeper understanding of emotional arousal and chemical senses can inform the design of products that evoke desired emotional responses, enhancing consumer satisfaction. By bridging the gap between sensory science and emotional response, this research has the potential to revolutionize approaches to flavor, fragrance, and product development across various sectors.
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2:05
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Exploring The Interplay Between Emotions And Chemosensory Stimuli: Past, Present And Future
Rachel Herz
Department of Psychiatry and Human Behavior, Brown University Medical School
Focusing primarily on the sense of smell and work that I have been involved in, this talk will review the main methodologies that have been used to investigate how emotions are elicited by chemosensory stimuli, some of the effects that this can have on behavior, and how emotional states can alter the perception of chemosensory stimuli. I will also discuss emerging technologies that aim to capture, store and release scents for mood alteration and emotional evocation. |
2:28
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A Multicomponential Approach To Emotional Experiences: The Case Of Relaxing And Stimulating Odors
Géraldine Coppin
UniDistance Suisse & Swiss Center for Affective Sciences, University of Geneva
According to the multicomponential approach to emotional experiences, an emotion is a multi-component response triggered by the way an event is appraised by an individual. This first emotional component – appraisal – depends on the individual’s current concerns, values, and goals. This component triggers an emotional response involving four other components: autonomic physiology, action tendency, expression, and feeling. The feeling component (or emotional experience) is often defined by a combination of valence (i.e., felt pleasure/displeasure) and arousal (i.e., felt calm/energy). Here we will discuss data testing whether the so-called “arousal effects” of odors can be identified via subjective reports, implicit measures, brain imaging data and peripheral physiology, while controlling for valence. We will first consider the subjective experience of relaxation or stimulation through cross-cultural experiments conducted in different languages. We will then show that the verbal report of a feeling is accompanied by implicit processing that reveals privileged associations between certain odors and their relaxing or stimulating properties. We will also discuss results on the short-term cerebral consequences of exposure to relaxing and stimulating odors. Finally, we will investigate the short-term physiological consequences of exposure to either relaxing or stimulating odors. This research will highlight the advantage of a multi-component approach to emotional experiences for fundamental research but also for applied and industrial research. |
2:50
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From Flavor To Feeling: Symrise'S Neuroscientific Exploration Of Emotional Connections In Taste
Mansi Patney, Jonathan Jacobs
Symrise AG
Emotional connections to flavors play a key role in shaping consumer preferences, as specific tastes and aromas can evoke powerful memories and emotions, enhancing product appeal and satisfaction. Flavors that hold cultural significance and tied to positive memories are more likely to be preferred, as they activate pleasure centers in the brain and foster brand loyalty (Herz, 2010; Prescott, 2012). Neuroscience offers valuable insights into consumer behavior by measuring subconscious responses that traditional methods may miss. Techniques like electroencephalography (EEG) provide a more nuanced understanding of decision-making (Plassmann et al., 2015; Ariely & Berns, 2010). EEG measures electrical potential differences on the scalp, allowing researchers to assess neural responses to stimuli in real-time, revealing implicit emotional and cognitive associations without relying on verbal feedback.
This study assesses consumer perceptions of two flavors for pain medication. Using the Symrise gen-isys neuroscience program, we employed EEG with 30 blindfolded male and female participants, ages 18-55, who are regular users of over-the-counter pain medication. Self-evaluation scores showed parity, while EEG results provided deeper insights into the emotional appeal and preference for the two flavors, demonstrating EEG’s ability to capture reliable, objective insights into emotional connections that self-reported data might overlook. These insights offer valuable guidance for product development and flavor optimization, highlighting the importance of balancing liking and excitement to drive consumer preference.
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3:08
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Generative Ai In Sensory Science: Data Crunching To Consumer Understanding
Michelle Murphy Niedziela
Nerdoscientist LLC
The integration of generative AI technologies into sensory research holds promise for advancing our understanding of consumer responses to taste and smell. Generative AI tools, such as large language models, have demonstrated potential in automating the analysis of qualitative data, expediting thematic coding, and identifying patterns within consumer narratives.
Moving beyond these established applications, this talk will explore the capacity of generative AI to enhance experimental design, simulate real-world sensory environments, and facilitate cross-modal insights. Using AI-driven virtual and augmented reality environments enables the recreation of ecologically valid contexts-such as noisy restaurants or serene outdoor settings-that are crucial for assessing sensory experiences in realistic conditions. AI's ability to model complex environmental variables, including ambient noise, lighting, and temperature, contributes to a more comprehensive understanding of how context influences sensory perception and satisfaction. Adaptive AI environments and chatbots can dynamically adjust to participant responses, offering novel approaches for studying the fluid and context-dependent nature of sensory experiences. The integration of behavioral science frameworks, such as decision-making models and theories of multisensory integration, enhances the interpretive value of AI-generated data, ensuring that insights, remain consumer-centric and actionable. Ethical considerations and the challenges of balancing technological advancements with consumer-focused research will also be discussed.
The potential of generative AI to transform sensory research offers new methodologies that align with behavioral science principles and provides opportunities for more efficient, robust, and ecologically valid studies.
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3:30
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Arousal And The Modulation Of Food-Related Perceptions And Emotions
John Prescott
Università degli Studi di Firenze, Italy & TasteMatters Research & Consulting, Australia
Across sensory systems, several stimulus collative characteristics, including intensity, novelty, complexity, and perceived threat, are known to elicit high levels of physiological and psychological arousal. Arousal and arousability are important elements in the emotional response to stimuli generally, but also specifically to foods, ultimately influencing food preferences and choices. In particular, food rejections are frequently linked to such arousal-inducing characteristics. Responses to food sensory properties are subject not just to variations in perceptual sensitivity due to genetics or experience – as in the case of widely rejected qualities such as bitterness or pungency - but also to the arousal potential of those stimuli. Moreover, this is linked to various enduring aspects of personality, suggesting that the impact of arousal on food choices is merely one aspect of a more general sensory sensitivity. The impact of diet on various health outcomes underlines the importance of understanding the relationship of arousal to food-related emotions and food choices. |
3:52
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How Reckitt Leverages Emotions To Better Understand The Consumer
Stephen Lillford1, Michael Nestrud2
1Reckitt, 2Curion Insights
There is no shortage of techniques available claiming to measure emotional reactions. Explicit measures like Snoopy Scales and emotion word lists such as EsSense25 and PANAS have provided for decades the ability to measure rational (System 2) emotional associations, whereas implicit (System 1) approaches such as IRT provide a measurement of the strength of more complex conceptual associations. Biometrics are yet another way to measure something about the human emotional experience. With all of these options, the challenge we have is not finding the perfect technique, but developing a research program to bridge the science with organizational needs and downstream decisions to benefit the consumer experience.
In this presentation we will explain how Reckitt has navigated these challenges to develop a robust program to measure emotions and help create products that truly go “beyond liking” by prioritizing emotional KPIs. Real life data will be shown comparing the performance of implicit and explicit measures providing clues to the underlying choice and decision processes consumers use to internalize product experiences and make choices. Finally, we’ll discuss a bit about the difficult change needed to create a product where liking is not the major KPI.
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7:00
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Motorizing The Chemical Senses
Alfredo Fontanini
Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, United States
Sensory processing and motor control are intimately linked. Animals use sensory information to guide and adjust movements and conversely move their sensors to actively sample the environment. In addition, perception and action are linked in the context of decision making. This is particularly the case for chemical senses, where the odor and the taste of a food are instrumental in guiding feeding behaviors. Despite this widely acknowledged relationship, sensory processing and motor control are still largely studied in isolation, as if they were independent processes. The goal of this symposium is to provide an integrative perspective on studying sensation and movement. The research presented relies on innovative behavioral approaches to analyze movements that are crucial to chemosensation. This symposium features work from four outstanding scientists. Jesse Goldberg will show how mice use their tongue to drink from a water spout that unexpectedly changes position and will present data on the role of the superior colliculus in touch-guided tongue control. Nicholas Hatsopoulos will discuss how monkeys use their tongue in the context of feeding and how motor and somatosensory cortices encode complex lingual shapes across a range of feeding behaviors. Dan Wesson will present research on how mice sniff to acquire odors and on the role of the mesolimbic dopaminergic system in promoting a switch from breathing to sniffing. Mitra Hartmann will present research on how rodents use their whiskers to determine the direction of air flow and on the importance of vibrissal vibrations in flow-sensing, a process with fundamental implications for odor plume detection. Altogether this symposium will highlight the importance of embracing a truly sensorimotor perspective in studying both chemosensation and movement. |
7:08
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A Collicular Map For Touch-Guided Tongue Control
Jesse Goldberg, Brendan Ito, Yongjie Gao, Brian Kardon
Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, United States
Accurate goal-directed behavior requires the sense of touch to be integrated with information about body position and ongoing motion. Behaviors like chewing, swallowing, and speech critically depend on precise tactile events on a rapidly moving tongue, but neural circuits for dynamic touch-guided tongue control are unknown. Using high-speed videography, we examined 3D lingual kinematics as mice drank from a water spout that unexpectedly changed position during licking, requiring re-aiming in response to subtle contact events on the left, center, or right surface of the tongue. Mice integrated information about both precise touch events and tongue position to re-aim ensuing licks. Surprisingly, touch-guided re-aiming was unaffected by photoinactivation of tongue sensory, premotor, and motor cortices but was impaired by photoinactivation of the lateral superior colliculus (latSC). Electrophysiological recordings identified latSC neurons with mechanosensory receptive fields for precise touch events that were anchored in tongue-centered, head-centered, or conjunctive reference frames. Notably, latSC neurons also encoded tongue position before contact, information important for tongue-to-head based coordinate transformations underlying accurate touch-guided aiming. Viral tracing revealed tongue sensory inputs to the latSC from the lingual trigeminal nucleus, and optical microstimulation in the latSC revealed a topographic map for aiming licks. These findings demonstrate for the first time that touch-guided tongue control relies on a collicular mechanosensorimotor map, analogous to collicular visuomotor maps associated with visually-guided orienting across many species. |
7:36
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Cortical Encoding Of Primate Tongue Shape During Feeding
Nicholas Hatsopoulos, Callum Ross
University of Chicago, Chicago, IL, United States
Dexterous tongue posture and movements underlies feeding behavior. The orofacial sensorimotor cortex has been implicated in the control of coordinated tongue kinematics, but little is known about how the brain encodes the tongue’s 3D soft-body deformation. Here we combined 3D x-ray video radiography to track implanted markers on the tongue, multi-electrode cortical recordings, and machine learning-based decoding to explore the cortical representation of lingual kinematics in Rhesus macaque monkeys. From the marker positions on the tongue, we calculated a set of standard tongue kinematic metrics such as sagittal flexion, roll, protrusion, as well as regional lengths and widths. We also used a Procrustes superimposition to remove translational, rotational, and scale changes in tongue posture so as to isolate variables associated with tongue shape. We then trained a recurrent neural network to decode these kinematic and shape variables from orofacial primary motor (M1of) and somatosensory cortical (S1of) activity during feeding. We show that both standard kinematic metrics and complex lingual shapes across a range of feeding behaviors could be decoded with high accuracy consistent with previous studies of the arm and hand. However, decoding from M1of neural populations consistently outperformed similarly sized populations from S1of. We are currently examining whether neurons preferentially encode position/postural variables as compared to velocity variables. |
8:04
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Invigorating The Transition From A Breath To A Sniff
Dan Wesson
University of Florida College of Medicine, Dept of Pharmacology & Therapeutics, Florida Chemical Senses Institute, Gainesville, FL, United States
The sniff is an essential component of both acquiring an odor and shaping the processing of odor information within the brain. Despite this importance, the neural systems which afford animals the ability to transition from basal breathing which serves the purpose of gas exchange, to engage in the voluntary act of sniffing, is unclear. We found that, in mice, dopamine release into two out of three ventral striatum subregions is coupled with bouts of sniffing and that stimulation of dopaminergic terminals in these regions drives increases in respiratory rate to initiate sniffing whereas inhibition of these terminals reduces respiratory rate. Both the firing of individual neurons and the activity of post-synaptic D1 and D2 dopamine receptor-expressing neurons are coupled with sniffing. Importantly, local antagonism of D1 and D2 receptors squelches sniffing. Ongoing work is investigating the input-output architecture of this circuit. Together, these results support a model whereby sniffing can be initiated by dopamine’s actions upon specific populations of ventral striatum neurons. We propose this system likely provides a neuromodulatory means whereby motivated states signaled by dopamine release tune the occurrence and frequency of sniffing in order for animals, including perhaps humans, to acquire and appropriately process odors. |
8:32
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Mechanical Components Of Chemical Plume Sensing
Mitra Hartmann1,2, Thomas Janssen1, Neelesh Patankar1, Shayan Heydari 3, Rajeev Jaiman3
1Department of Mechanical Engineering, Northwestern University, Evanston, IL, United States, 2Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States, 3Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada
In order to efficiently track chemical plumes, animals must determine the direction of fluid flow. How do animals sense flow direction? In rats, the large mystacial vibrissae (whiskers) have been shown to play a critical role in flow-sensing behaviors. Recent results from our laboratory demonstrate that whiskers bend in the direction of airflow and then vibrate about this new deflected position. The magnitude of bending and vibration both correlate with airspeed, and vibration frequency is related to the whisker’s natural frequencies. This phenomenon presents an apparent paradox: rat whiskers are so thin that vortex-induced vibrations should not occur, because the Reynolds number (Re) is well below critical. We investigated the underlying physical mechanisms driving whisker vibrations, considering both structural nonlinearities and fluid-structure interactions. Our findings indicate that vibrations result from a coupling of these two mechanisms, revealing a novel explanation for vibrations at subcritical Re. This discovery introduces new principles of vibrations at subcritical Re, with broad implications for biological systems across species. Results will be discussed in the context of animal search behaviors. |
