Gustatory Processing Research Articles

The effect of multiband sequences on statistical outcome measures in functional magnetic resonance imaging using a gustatory stimulus

Recent technical developments have led to the invention of multiband functional magnetic resonance imaging (fMRI) sequences that allow for faster sampling rates. However, some studies have highlighted problems with these sequences, leading to a decreased temporal signal-to-noise ratio (tSNR). In addition, this temporal noise may interfere with detecting reward-related responses in mesolimbic regions. The blood-oxygen-level-dependent signal utilized in the majority of fMRI measurements is relatively slow. Furthermore, the cerebral response to gustatory stimuli would also be relatively slow. Therefore, given the temporal noise issues with multiband sequences, it is unclear whether multiband sequences are necessary for fMRI studies using gustatory stimuli. We thus conducted an fMRI experiment using a gustatory stimulus to investigate the effects of multiband sequences and increased sampling rates on statistical outcome measures. A single-band sequence with a repetition time (TR) of 2 s of phantom fMRI data and gustatory fMRI data from the gustatory regions exhibited the highest tSNR, although the tSNR of this sequence of gustatory fMRI was not statistically different from tSNR of multiband sequences with a TR of 2 s in any of the selected region of interests. Conventional general linear model analysis of fMRI showed that single-band sequences are more advantageous than multiband sequences for detecting brain responses to gustatory stimuli in the primary gustatory cortex. In addition, a Bayesian data comparison showed that data derived from a single-band sequence with a TR of 2 s was optimal for inferring neuronal connectivity in gustatory processing. Therefore, a conventional single-band sequence with a TR of 2 s is more appropriate for fMRI with gustatory stimuli. Image acquisition sequences should be selected aligned with the study objectives and target brain regions.

Exploring impairments in gustatory processing in a mouse model of Alzheimer’s Disease

Exploring impairments in gustatory processing in a mouse model of Alzheimer’s Disease

Interconnected sub-networks of the macaque monkey gustatory connectome.

Macroscopic taste processing connectivity was investigated using functional magnetic resonance imaging during the presentation of sour, salty, and sweet tastants in anesthetized macaque monkeys. This examination of taste processing affords the opportunity to study the interactions between sensory regions, central integrators, and effector areas. Here, 58 brain regions associated with gustatory processing in primates were aggregated, collectively forming the gustatory connectome. Regional regression coefficients (or β-series) obtained during taste stimulation were correlated to infer functional connectivity. This connectivity was then evaluated by assessing its laterality, modularity and centrality. Our results indicate significant correlations between same region pairs across hemispheres in a bilaterally interconnected scheme for taste processing throughout the gustatory connectome. Using unbiased community detection, three bilateral sub-networks were detected within the graph of the connectome. This analysis revealed clustering of 16 medial cortical structures, 24 lateral structures, and 18 subcortical structures. Across the three sub-networks, a similar pattern was observed in the differential processing of taste qualities. In all cases, the amplitude of the response was greatest for sweet, but the network connectivity was strongest for sour and salty tastants. The importance of each region in taste processing was computed using node centrality measures within the connectome graph, showing centrality to be correlated across hemispheres and, to a smaller extent, region volume. Connectome hubs exhibited varying degrees of centrality with a prominent leftward increase in insular cortex centrality. Taken together, these criteria illustrate quantifiable characteristics of the macaque monkey gustatory connectome and its organization as a tri-modular network, which may reflect the general medial-lateral-subcortical organization of salience and interoception processing networks.

Olfactory and Gustatory Dysfunction in COVID-19: A Global Bibliometric and Visualized Analysis.

Coronavirus illness (COVID-19) has been found to alter infected people's sense of smell and taste. However, the pathobiology of this virus is not yet known. Therefore, it is critical to investigate the influence of COVID-19 infection on olfactory and gustatory processes. Therefore, we use bibliometric analysis on COVID-19 and olfactory and/or gustatory dysfunction publications to provide studies perspective. A bibliometric literature search was performed in the Scopus database. The number and type of publications, countries for publications, institutional sources for publications, journals for publications, citation patterns, and funding agencies were analyzed using Microsoft Excel or VOSviewer. In addition, the VOSviewer 1.6.17 software was used to analyze and visualize hotspots and collaboration patterns between countries. Scopus has published 187 088 documents for COVID-19 in all study fields at the time of data collection (July 26, 2021). A total of 1740 documents related to olfactory and/or gustatory dysfunction were recovered. The countries most relevant by the number of publications were the United States (n = 362, 20.80%), Italy (n = 255, 14.66%), and the United Kingdom (n = 173, 9.94%). By analyzing the terms in the titles and abstracts, we identified 2 clusters related to olfactory and/or gustatory dysfunction research, which are "diagnosis and test methods" and "prognosis and complications of the disease." This is the first bibliometric analysis of publications related to COVID-19 and olfactory and/or gustatory dysfunction. This study provides academics and researchers with useful information on the publishing patterns of the most influential publications on COVID-19 and olfactory and/or gustatory dysfunction. Olfactory and/or gustatory dysfunction as indices of suspicion for the empirical diagnosis of coronavirus infection is a new hotspot in this field.

Gustatory event-related potential alterations in olfactory dysfunction patients.

The phenomenon that longstanding impaired olfactory function is associated with the decreased gustatory function was described in present studies, which was seems attributed to mutual chemosensory interactions. And the interaction between olfaction and gustation still needs more research to figure out. The objective of the study was to investigate how the taste was influenced by olfactory impairment in the central pathway. We tested 33 subjects with normal (n = 19) or impaired (n = 14) olfactory function for their gustatory event-related potentials (gERPs). Validated tests were used for olfactory and gustatory testing (Sniffin’ Sticks, gERPs, and three-drop test). This study reported an objective gustatory function decline in olfactory dysfunction participants. However, it also reported the increased gustatory event-related potentials of olfactory dysfunction participants, especially at the frontal electrode (FZ) and electrode 16 (E16), and the reduced latency of P2 peak of them at electrode 21 (E21), while no obvious difference was observed at the centro-parietal electrode (PZ). Inferior insula might be the main response area for the increase in gERPs, and this increase averaged amplitude of the P2 component may attribute to compensation of the secondary gustatory response that occurred in the gustatory processing of olfactory-impaired patients.

On the Political Biology of Eating and Performing (with) Food

Performance research involving food frequently focuses the ‘political economy of food sovereignty' where political action involves providing visibility to power differentials in righting injustices and/or celebrating differences. Alimentary and gustatory processes of eating are often assumed as ‘naturally' given and rarely put under a critical biopolitical lens. This essay, which zigzags between three food performances and three interdisciplinary concepts, attempts to reconfigure normative conceptions of the biopolitical; by interrogating instead the politics of biology away from transcendental conditions and anthropogenic definitions that lead to a radical insufficiency of justice to cater for difference. Firstly, Giorgio Agamben's concept of bare life in his biopolitics is argued to be itself ontologically political, through performances of eating that decentre the human in definitions of biological life. This reveals and complicates biology's implicit technicity as that which demarcates what is human life from what is not. Secondly, food performances conjure the ‘enteric imagination' that bring into focus the entanglements of instinctual and ethical life. These performances, with concrete coordinative connections between eating and hearing make porous the epistemological domains between individuality and communality, organic and inorganic, life and death, towards a richer idea of biopolitics as ‘lived-intuition.' Lastly, the essay outlines Gilles Deleuze's ‘becoming-minor’ as a creative and affirmative politics, arriving not as the result of majoritarian agreement nor counter-hegemonic movements, but rather the aggregation of a myriad of molecular, minor events where inventions and conjugations of specific, unforeseen and autonomous modes of becoming exist. Focusing on the politics of biology in this way provides alternatives to idealistic definitions of life whose exigencies can be seen not only in relation in their binary opposition to death, but moves towards a positive one, immanent to multiple modalities of being. The biopolitics of eating does not oppose but stays with the inarticulable but nevertheless real sensoria, providing a surface for experimentation that produces abstractions, concepts, disciplines, gestures and alimentary processes, towards a biopolitics of food that acknowledges that the biological is in itself already political.

Implicit and explicit measures of the sensory and hedonic analysis of beer: The role of tasting expertise

Measures of drinking and eating behaviors may be assessed both explicitly (e.g., sensory and quality judgments) and implicitly (e.g., Electroencephalography, EEG), although the relationship between the results of both approaches remains unclear and each might be differentially affected by acquired knowledge. The main aim of the present study was to determine the strength of the relationship between these measures in sensory and hedonic processing of beers depending on the degree of tasting expertise. Beer experts, experts in non-beer beverages or edibles, and non-expert consumers took part in a sensory analysis procedure where they rated beers in terms of their sensory attributes and general quality—visual, olfactory, and gustatory phases—as well as their global hedonic value while their brain activity was recorded. The results suggest that participants evaluated the sensory properties of the beers in a rather similar manner. However, during the gustatory phase, experts and general tasters differed in terms of the activation of brain areas related to memory processes, while general tasters and consumers differed in brain activation related to hedonic processing. The relationship between self-reported quality judgments and EEG activity — particularly in relation to recognition and working memory components — appeared to be stronger in experts in comparison with the other groups (lowest |r| = 0.67, p < .01). Although lower in number, significant relationships were also found in general tasters and consumers, primarily involving hedonic processing (lowest |r| = 0.58, p < .01) and recognition memory (lowest |r| = 0.57, p < .01) components. Moreover, those relationships differed significantly, mostly between experts and consumers (lowest |z| = 2.68, p < .01), in terms of the involvement of working memory components. Taken together, the results of this study suggest that beer experts have a more efficient pattern of gustatory processing and show a better fit between explicit (judgments) and implicit (EEG) measures of sensory and hedonic quality of beers.

Adipokinetic hormone (AKH), energy budget and their effect on feeding and gustatory processes of foraging honey bees

The adipokinetic hormone (AKH) of insects is considered an equivalent of the mammalian hormone glucagon as it induces fast mobilization of carbohydrates and lipids from the fat body upon starvation. Yet, in foraging honey bees, which lack fat body storage for carbohydrates, it was suggested that AKH may have lost its original function. Here we manipulated the energy budget of bee foragers to determine the effect of AKH on appetitive responses. As AKH participates in a cascade leading to acceptance of unpalatable substances in starved Drosophila, we also assessed its effect on foragers presented with sucrose solution spiked with salicin. Starved and partially-fed bees were topically exposed with different doses of AKH to determine if this hormone modifies food ingestion and sucrose responsiveness. We found a significant effect of the energy budget (i.e. starved vs. partially-fed) on the decision to ingest or respond to both pure sucrose solution and sucrose solution spiked with salicin, but no effect of AKH per se. These results are consistent with a loss of function of AKH in honey bee foragers, in accordance with a social life that implies storing energy resources in the hive, in amounts that exceed individual needs.

Uncommon case of complete loss of hunger following an isolated left insular stroke

ABSTRACT The insula has long been among the least understood regions of the human brain, in part due to its restricted accessibility. Mounting evidence suggests that the insula is a prominent player in gustatory, interoceptive, and emotional processing, and likely integrates these different functions to contribute to the homeostatic control of food intake. Here we report the case of a young adult patient who lost the subjective experience of hunger following an ischemic stroke localized in the posterior left insula. The loss of hunger was not attributable to medication, substance use, or a clinical disorder, and lasted for a period of 15 months. In line with the role attributed to the insula in gustation and interoception, we suggest that the insula integrates information about taste, interoception, and the hedonic value of food in the service of homeostatic regulation.

Sour aversion in frontotemporal dementia: a case report and review on physiologic-anatomic mechanisms

ABSTRACT Frontotemporal dementia (FTD) is a common cause of early-onset dementia characterized by behavioral and personality changes, as well as, altered eating habits. FTD is associated with complex changes in neural networks of gustatory processing which may be responsible for eating abnormalities. Here, we present a 66-years-old lady suffered from behavioral variant of FTD with an interesting symptom of food aversion, typically sour foods.

Early olfactory, but not gustatory processing, is affected by the selection of heritable cognitive phenotypes in honey bee.

Associative learning enables animals to predict rewards or punishments by their associations with predictive stimuli, while non-associative learning occurs without reinforcement. The latter includes latent inhibition (LI), whereby animals learn to ignore an inconsequential 'familiar' stimulus. Individual honey bees display heritable differences in expression of LI. We examined the behavioral and neuronal responses between honey bee genetic lines exhibiting high and low LI. We observed, as in previous studies, that high LI lines learned a familiar odor more slowly than low LI bees. By measuring gustatory responses to sucrose, we determined that perception of sucrose reward was similar between both lines, thereby not contributing to the LI phenotype. We then used extracellular electrophysiology to determine differences in neural responses of the antennal lobe (AL) to familiar and novel odors between the lines. Low LI bees responded significantly more strongly to both familiar and novel odors than the high LI bees, but the lines showed equivalent differences in response to the novel and familiar odors. This work suggests that some effects of genotype are present in early olfactory processing, and those effects could complement how LI is manifested at later stages of processing in brains of bees in the different lines.

A Systematic Review and Activation Likelihood Estimation Meta-Analysis of fMRI Studies on Sweet Taste in Humans

ABSTRACTBackgroundThe reward value of palatable foods is often cited as an important influence on eating behaviors, including intake of sugars. However, human neuroimaging studies have generated conflicting evidence on the basic neural representation of taste and reward responses to caloric sweeteners (sucrose and glucose), and most relevant studies have used small subject numbers.ObjectiveWe conducted a systematic review and a coordinate-based meta-analysis of studies reporting brain responses to oral sugar solutions.MethodsA systematic search of MEDLINE, Scopus, and PsycINFO through October 2019 identified fMRI studies (in healthy human adults, including those with overweight or obesity) assessing differences in responses to purified sweet and nonsweet taste stimuli. Data were extracted with the primary objective of quantifying evidence for the activation of brain regions associated with caloric sweet taste sensation. We used activation likelihood estimation meta-analysis methods. We also performed multiple sensitivity analyses to assess the generality of effects.ResultsOf 455 unique articles, 15 met the criteria for inclusion. These contributed to 2 primary meta-analyses: 1) sucrose (13 experiments, 179 coordinates, n = 241) and 2) sucrose + glucose (16 experiments, 209 coordinates, n = 262). Consistent activation was apparent in primary taste areas: insula (69.2% of studies) and opercular cortex (76.9% of studies), precentral gyri (53.9% of studies), and globus pallidus and postcentral gyrus (30.8% of studies for each). Evidence of reward activity (caudate) was seen in the primary analyses (30.8% of studies) but not in sensitivity analysis.ConclusionsWe confirm the importance of primary taste areas for gustatory processing in human adults. We also provide tentative evidence for reward-related caudate activity in relation to the sweet taste of caloric sugars. A number of factors affect the observation and interpretation of brain responses, including reward-related activity. Firm conclusions require confirmation with large data set studies.

Masking the Detection of Taste Stimuli in Rats: NaCl and Sucrose.

While psychophysical and neurophysiological assessments of taste sensitivity to single chemical compounds have revealed some fundamental properties of gustatory processing, taste stimuli are rarely ingested in isolation. Arguably, the gustatory system was adapted to identify and report the presence of numerous chemicals ingested concurrently. To begin systematically exploring the detectability of a target stimulus in a background in rodents, we used a gustometer to train rats in a 2-response operant task to detect either NaCl (n = 8) or sucrose (n = 8) dissolved in water, and then tested the sensitivity of rats to the trained NaCl stimulus dissolved in a sucrose masker (0.3, 0.6, or 1.0 M, tested consecutively) versus sucrose, or the trained sucrose stimulus dissolved in a NaCl masker (0.04, 0.2, or 0.4 M) versus NaCl. Detection thresholds (EC50 values) were determined for the target stimulus dissolved in each concentration of the masker. Except for 0.04 M NaCl, all masker concentrations tested increased the target stimulus EC50. Target stimulus detectability decreased systematically as masker concentrations increased. The shift in liminal sensitivity for either target was similar when the threshold for the masker was considered. At least for these prototypical stimuli, it appears that the attenuating impact of a masker on the detection of a target stimulus depends on sensitivity to the masking stimulus. Further study will be required to generalize these results and extend them to more complex maskers, and to discern neural circuits involved in the detection of specific taste signals in the context of noisy backgrounds.

Food cue recruits increased reward processing and decreased inhibitory control processing in the obese/overweight: An activation likelihood estimation meta-analysis of fMRI studies

IntroductionGrowing researches have shown that obese/overweight and healthy weight individuals exhibit different neural responses to food-related stimuli. Accordingly, researchers proposed several theories to explain these differences. Hereon, meta-analyses were conducted using activation likelihood estimation (ALE) to verify these theories and specify the reason of overeating from two aspects. Materials and MethodsPubmed, Web of Science and Neurosynth were searched for the current study and screened according to inclusion criteria. Firstly, neural responses to visual food cues versus non-food images were compared between obese/overweight and healthy weight individuals. Then, neural activation to high-calorie food images versus low-calorie food/non-food visual stimuli was further investigated among the two populations. Coordinates in included studies were recorded and analysed by Ginger ALE software under threshold at uncorrected p < 0.001 with cluster-level p < 0.05 (cFWE). ResultsEleven and seven studies were found in the first and second set of meta-analysis, respectively. The first meta-analysis showed that obese/overweight have hyper-responsivity in reward area and hypo-responsivity in both gustatory processing and inhibitory control area. The second meta-analysis indicated that the reward responsivity in the obese/overweight individuals was amplified and healthy weight individuals had higher activation in areas associated with gustatory processing in response to high-calorie food images. ConclusionsOur results showed that the obese/overweight exhibit hyper-responsivity in brain regions involved in reward processing for visual food cue which provide strong support for incentive-sensitization theory of obesity and healthy weight individuals showed higher response in inhibitory control region which support the inhibitory control deficit theory of obesity.

Differential Cerebral Gustatory Responses to Sucrose, Aspartame, and Stevia Using Gustatory Evoked Potentials in Humans.

Aspartame and Stevia are widely substituted for sugar. Little is known about cerebral activation in response to low-caloric sweeteners in comparison with high-caloric sugar, whereas these molecules lead to different metabolic effects. We aimed to compare gustatory evoked potentials (GEPs) obtained in response to sucrose solution in young, healthy subjects, with GEPs obtained in response to aspartame and Stevia. Twenty healthy volunteers were randomly stimulated with three solutions of similar intensities of sweetness: Sucrose 10 g/100 mL of water, aspartame 0.05 g/100 mL, and Stevia 0.03 g/100 mL. GEPs were recorded with EEG (Electroencephalogram) electrodes. Hedonic values of each solution were evaluated using the visual analog scale (VAS). The main result was that P1 latencies of GEPs were significantly shorter when subjects were stimulated by the sucrose solution than when they were stimulated by either the aspartame or the Stevia one. P1 latencies were also significantly shorter when subjects were stimulated by the aspartame solution than the Stevia one. No significant correlation was noted between GEP parameters and hedonic values marked by VAS. Although sucrose, aspartame, and Stevia lead to the same taste perception, cerebral activation by these three sweet solutions are different according to GEPs recording. Besides differences of taste receptors and cerebral areas activated by these substances, neural plasticity, and change in synaptic connections related to sweet innate preference and sweet conditioning, could be the best hypothesis to explain the differences in cerebral gustatory processing after sucrose and sweeteners activation.

Adiposity Related Brain Plasticity Induced by Bariatric Surgery.

Previous magnetic resonance imaging (MRI) studies revealed structural-functional brain reorganization 12 months after gastric-bypass surgery, encompassing cortical and subcortical regions of all brain lobes as well as the cerebellum. Changes in the mean of cluster-wise gray/white matter density (GMD/WMD) were correlated with the individual loss of body mass index (BMI), rendering the BMI a potential marker of widespread surgery-induced brain plasticity. Here, we investigated voxel-by-voxel associations between surgery-induced changes in adiposity, metabolism and inflammation and markers of functional and structural neural plasticity. We re-visited the data of patients who underwent functional and structural MRI, 6 months (n = 27) and 12 months after surgery (n = 22), and computed voxel-wise regression analyses. Only the surgery-induced weight loss was significantly associated with brain plasticity, and this only for GMD changes. After 6 months, weight loss overlapped with altered GMD in the hypothalamus, the brain’s homeostatic control site, the lateral orbitofrontal cortex, assumed to host reward and gustatory processes, as well as abdominal representations in somatosensory cortex. After 12 months, weight loss scaled with GMD changes in right cerebellar lobule VII, involved in language-related/cognitive processes, and, by trend, with the striatum, assumed to underpin (food) reward. These findings suggest time-dependent and weight-loss related gray matter plasticity in brain regions involved in the control of eating, sensory processing and cognitive functioning.

Recognizing Taste: Coding Patterns Along the Neural Axis in Mammals.

The gustatory system encodes information about chemical identity, nutritional value, and concentration of sensory stimuli before transmitting the signal from taste buds to central neurons that process and transform the signal. Deciphering the coding logic for taste quality requires examining responses at each level along the neural axis-from peripheral sensory organs to gustatory cortex. From the earliest single-fiber recordings, it was clear that some afferent neurons respond uniquely and others to stimuli of multiple qualities. There is frequently a "best stimulus" for a given neuron, leading to the suggestion that taste exhibits "labeled line coding." In the extreme, a strict "labeled line" requires neurons and pathways dedicated to single qualities (e.g., sweet, bitter, etc.). At the other end of the spectrum, "across-fiber," "combinatorial," or "ensemble" coding requires minimal specific information to be imparted by a single neuron. Instead, taste quality information is encoded by simultaneous activity in ensembles of afferent fibers. Further, "temporal coding" models have proposed that certain features of taste quality may be embedded in the cadence of impulse activity. Taste receptor proteins are often expressed in nonoverlapping sets of cells in taste buds apparently supporting "labeled lines." Yet, taste buds include both narrowly and broadly tuned cells. As gustatory signals proceed to the hindbrain and on to higher centers, coding becomes more distributed and temporal patterns of activity become important. Here, we present the conundrum of taste coding in the light of current electrophysiological and imaging techniques at several levels of the gustatory processing pathway.

Neuromedin U signaling regulates memory retrieval of learned salt avoidance through modulation of the neural circuit processing gustatory information

Event Abstract Back to Event Neuromedin U signaling regulates memory retrieval of learned salt avoidance through modulation of the neural circuit processing gustatory information Jan Watteyne1*, Petrus Van Der Auwera1, Katleen Peymen1, Charline Borghgraef1, Elke Vandewyer1, Liliane Schoofs1 and Isabel Beets1 1 KU Leuven, Belgium Learning and memory are regulated by neuromodulatory pathways, but the contribution and temporal requirement of most neuromodulators in a learning circuit are unknown. Neuropeptides are important neuromodulators that are mainly thought to exert their function through G protein-coupled receptors. Caenorhabditis elegans displays various adaptive behaviors, including gustatory aversive learning, a type of associative learning in which normal chemotaxis towards salt is modulated by pre-exposure to this substance in the absence of food. Here, we identify the evolutionary conserved neuromedin U (NMU) neuropeptide family as a regulator of memory retrieval in C. elegans gustatory aversive learning. The NMU homolog CAPA-1 and its G protein-coupled receptor NMUR-1 are required for the expression of learned salt avoidance. By combining neurogenetic manipulation with quantitative behavioral analysis, we show that NMU signaling modulates two navigational strategies for salt chemotaxis. Aversive learning depends on the release of CAPA-1 neuropeptides from a sensory neuron pair that responds to salt stimuli in an experience-dependent manner. Optogenetic silencing of these CAPA-1 neurons blocks the immediate retrieval, but not the acquisition, of learned salt avoidance. Finally, cell-specific rescue experiments show CAPA-1 neuropeptides to act on the NMUR-1 receptor in a sensory neuron pair that does not participate in salt chemotaxis under basal conditions. Our findings thus demonstrate how aversive conditioning engages NMU signaling to acutely recruit sensory neurons to the salt sensory circuit, hereby modulating gustatory processing and fine tuning the appropriate locomotor program in response to a detrimental sensory context. Because NMU signaling is conserved across bilaterian animals, our findings incite further research into its function in other memory and decision-making circuits. Acknowledgements This research is supported by the Research Foundation - Flanders (FWO) and by European Research Council Grant 340318. Keywords: Neuropeptides, C. elegans, Avoidance Learning, memory retrieval, decision-making Conference: 13th National Congress of the Belgian Society for Neuroscience , Brussels, Belgium, 24 May - 24 May, 2019. Presentation Type: Poster presentation Topic: Behavioral/Systems Neuroscience Citation: Watteyne J, Van Der Auwera P, Peymen K, Borghgraef C, Vandewyer E, Schoofs L and Beets I (2019). Neuromedin U signaling regulates memory retrieval of learned salt avoidance through modulation of the neural circuit processing gustatory information. Front. Neurosci. Conference Abstract: 13th National Congress of the Belgian Society for Neuroscience . doi: 10.3389/conf.fnins.2019.96.00051 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Mr. Jan Watteyne, KU Leuven, Leuven, Belgium, jwatteyne@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jan Watteyne Petrus Van Der Auwera Katleen Peymen Charline Borghgraef Elke Vandewyer Liliane Schoofs Isabel Beets Google Jan Watteyne Petrus Van Der Auwera Katleen Peymen Charline Borghgraef Elke Vandewyer Liliane Schoofs Isabel Beets Google Scholar Jan Watteyne Petrus Van Der Auwera Katleen Peymen Charline Borghgraef Elke Vandewyer Liliane Schoofs Isabel Beets PubMed Jan Watteyne Petrus Van Der Auwera Katleen Peymen Charline Borghgraef Elke Vandewyer Liliane Schoofs Isabel Beets Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Fat perception in the human frontal operculum, insular and somatosensory cortex

Here, we combined magnetic resonance imaging with lesion-symptom mapping in patients with chronic brain lesions to investigate brain representations of sugar and fat perception. Patients and healthy controls rated chocolate milkshakes that only differed in sugar or fat content. As compared to controls, patients showed an impaired fat, but not sugar perception. Impairments in fat perception overlapped with the anterior insula and frontal operculum, together assumed to underpin gustatory processing. We also identified the mid-dorsal insula as well as the primary and secondary somatosensory cortex - regions previously assumed to integrate oral-sensory inputs. These findings suggest that fat perception involves a specific set of brain regions that were previously reported to underpin gustatory processing and oral-sensory integration processes.

FV10. Gastric-bypass surgery induced widespread neural plasticity of the obese human brain

Bariatric surgery has become the gold standard for the treatment of morbid obesity (body mass index (BMI) ⩾ 40 kg/m2), but its plastic influences on the obese brain remain largely unexplored. Here, we combined structural and functional magnetic resonance brain imaging (MRI) in twenty-seven patients (BMI 47.8 ± 5.5 kg/m2) undergoing gastric-bypass surgery and fourteen non-obese controls (BMI 24.7 ± 3.4 kg/m2). Over the first year after surgery, patients presented changes in gray matter density (GMD) in the cerebral cortex of all lobes, subcortical structures as well as the cerebellum, but no changes in white matter water diffusivity throughout the brain. Related to the BMI loss, we identified altered GMD in the hypothalamus, the brain’s homeostatic control site, the lateral orbitofrontal cortex, assumed to host reward and gustatory processes, as well as bilateral abdominal representations in somatosensory cortex. Voxel-by-voxel regression analyses revealed that all GMD changes were associated with elevated regional homogeneity of spontaneous neural activity (ReHo) in blood-oxygenation level-dependent signals. Spatial–temporal integration of structural and functional MRI suggests that gastric-bypass surgery induced widespread plastic changes in cortical structure that concurrently homogenized the functional profile of the cortex.