scholarly journals Drosophila Central Taste Circuits in Health and Obesity

2021 ◽  
Author(s):  
Shivam Kaushik ◽  
Shivangi Rawat ◽  
Pinky Kain
Keyword(s):  
Internal State ◽  
Taste Preference ◽  
Taste Perception ◽  
Model Organisms ◽  
Gustatory System ◽  
Neuronal Circuits ◽  
Neural Basis ◽  
Metabolic Conditions ◽  
Feeding Choices ◽  
Feeding Behaviours

When there is a perturbation in the balance between hunger and satiety, food intake gets mis-regulated leading to excessive or insufficient eating. In humans, abnormal nutrient consumption causes metabolic conditions like obesity, diabetes, and eating disorders affecting overall health. Despite this burden on society, we currently lack enough knowledge about the neuronal circuits that regulate appetite and taste perception. How specific taste neuronal circuits influence feeding behaviours is still an under explored area in neurobiology. The taste information present at the periphery must be processed by the central circuits for the final behavioural output. Identification and understanding of central neural circuitry regulating taste behaviour and its modulation by physiological changes with regard to internal state is required to understand the neural basis of taste preference. Simple invertebrate model organisms like Drosophila melanogaster can sense the same taste stimuli as mammals. Availability of powerful molecular and genetic tool kit and well characterized peripheral gustatory system with a vast array of behavioural, calcium imaging, molecular and electrophysiological approaches make Drosophila an attractive system to investigate and understand taste wiring and processing in the brain. By exploiting the gustatory system of the flies, this chapter will shed light on the current understanding of central neural taste structures that influence feeding choices. The compiled information would help us better understand how central taste neurons convey taste information to higher brain centers and guide feeding behaviours like acceptance or rejection of food to better combat disease state caused by abnormal consumption of food.

scholarly journals Threat induces changes in cardiac activity and metabolism negatively impacting survival in flies

2020 ◽  
Author(s):  
Natalia Barrios ◽  
Matheus Farias ◽  
Marta A Moita
Keyword(s):  
Internal State ◽  
Brain Activity ◽  
Dynamic Environment ◽  
Cardiac Activity ◽  
Fruit Fly ◽  
Physiological Changes ◽  
Neural Basis ◽  
Cardiac Responses ◽  
Cardiac Deceleration ◽  
Defensive Behaviours

AbstractAdjusting to a dynamic environment involves fast changes in the body’s internal state, characterized by coordinated alterations in brain activity, physiological and motor responses. Threat-induced defensive states are a classic example of coordinated adjustment of bodily responses, being cardiac regulation one of the best characterized in vertebrates. A great deal is known regarding the neural basis of invertebrate defensive behaviours, mainly in Drosophila melanogaster. However, whether physiological changes accompany these remains unknown. Here, we set out to describe the internal bodily state of fruit flies upon an inescapable threat and found cardiac acceleration during running and deceleration during freezing. In addition, we found that freezing leads to increased cardiac pumping from the abdomen towards the head-thorax, suggesting mobilization of energy resources. Concordantly, threat-triggered freezing reduces sugar levels in the hemolymph and renders flies less resistant to starvation. The cardiac responses observed during freezing were absent during spontaneous immobility, underscoring the active nature of freezing response. Finally, we show that baseline cardiac activity predicts the amount of freezing upon threat. This work reveals a remarkable similarity with the cardiac responses of vertebrates, suggesting an evolutionarily convergent defensive state in flies. Our findings are at odds with the widespread view that cardiac deceleration while freezing has first evolved in vertebrates and that it is energy sparing. Investigating the physiological changes coupled to defensive behaviours in the fruit fly has revealed that freezing is costly, yet accompanied by cardiac deceleration, and points to heart activity as a key modulator of defensive behaviours.

scholarly journals Hypothalamic neuronal circuits regulating hunger-induced taste modification

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ou Fu ◽  
Yuu Iwai ◽  
Masataka Narukawa ◽  
Ayako W. Ishikawa ◽  
Kentaro K. Ishii ◽  
...  
Keyword(s):  
Lateral Hypothalamus ◽  
Critical Role ◽  
Taste Preference ◽  
Lateral Septum ◽  
Gustatory System ◽  
Lateral Habenula ◽  
Mechanistic Insight ◽  
Aversive Taste ◽  
Neuronal Mechanisms ◽  
Internal States

Abstract The gustatory system plays a critical role in sensing appetitive and aversive taste stimuli for evaluating food quality. Although taste preference is known to change depending on internal states such as hunger, a mechanistic insight remains unclear. Here, we examine the neuronal mechanisms regulating hunger-induced taste modification. Starved mice exhibit an increased preference for sweetness and tolerance for aversive taste. This hunger-induced taste modification is recapitulated by selective activation of orexigenic Agouti-related peptide (AgRP)-expressing neurons in the hypothalamus projecting to the lateral hypothalamus, but not to other regions. Glutamatergic, but not GABAergic, neurons in the lateral hypothalamus function as downstream neurons of AgRP neurons. Importantly, these neurons play a key role in modulating preferences for both appetitive and aversive tastes by using distinct pathways projecting to the lateral septum or the lateral habenula, respectively. Our results suggest that these hypothalamic circuits would be important for optimizing feeding behavior under fasting.

Psychological Perspectives on Taste

Psychology ◽  
2019 ◽  
Author(s):  
Emily E. Perszyk ◽  
Bob Stewart ◽  
Haley R. Roland
Keyword(s):  
Sensory Modality ◽  
Taste Receptor ◽  
Functional Brain Imaging ◽  
Taste Perception ◽  
Chemical Components ◽  
Neural Pathways ◽  
Gustatory System ◽  
Imaging Data ◽  
Receptor Cells ◽  
Taste Receptor Cells

The word taste commonly evokes the experience of a robust California red wine, a perfectly seasoned and roasted duck breast, or a decadent Belgian chocolate. In fact, the perceptual experience that accompanies ingestion of food is most correctly termed flavor. Flavor comprises combined elements of olfactory (i.e., retronasal odor), somatosensory (e.g., texture and temperature), and gustatory sensations that attend ingestion. In contrast, taste refers exclusively to the perceptions and behaviors that arise when chemical components of food stimulate the gustatory apparatus of the oral cavity, namely taste receptor cells found within taste buds. Consequent neural activity in taste nerves and taste-related areas of the brain lead to gustatory sensation and perception. There is general agreement that activation of the taste system results in the perception of five unique taste qualities, or basic tastes, in humans: sweet, sour, salty, bitter, and umami. It has long been appreciated that perception of these tastes plays a pivotal role in feeding by providing the organism with an appraisal of food nutrient value and/or potential toxicity. Though much remains unknown, our understanding of the gustatory system has burgeoned since 2000. Advances in molecular genetic techniques, for example, provided the launchpad for explosive growth in our understanding of the basic molecular and cellular physiology of taste receptor cells. This information, in turn, has stimulated theoretical, conceptual, and experimental reappraisal of long-standing ideas about the neuroanatomical and neurophysiological bases of taste stimulus coding and perception. Simultaneously, progress in functional brain-imaging technologies permitted non-invasive investigation of the neural pathways and processes involved in taste perception in humans. Results from functional imaging studies have confirmed, extended, and clarified findings from previous psychophysical studies in healthy participants and in patients with peripheral and central nervous system lesions. These studies have also revealed neural correlates of flavor, taste and flavor hedonics, and food-related reward. Combined molecular, behavioral, psychophysical, and imaging data suggest that taste can influence and be influenced by disease. Taste modulates metabolism and contributes to diseases such as obesity, diabetes, and hypertension. Various diseases and the drugs used to treat them can have strong negative impacts on taste, which can lead to impaired nutrition and diminished quality of life. The reciprocal influences of disease and taste signal the importance of considering this sensory modality in health, nutrition, and food industry policies and practice.

scholarly journals Rest Is Required to Learn an Appetitively-Reinforced Operant Task in Drosophila

2021 ◽  
Vol 15 ◽  
Author(s):  
Timothy D. Wiggin ◽  
Yungyi Hsiao ◽  
Jeffrey B. Liu ◽  
Robert Huber ◽  
Leslie C. Griffith
Keyword(s):  
Operant Conditioning ◽  
Molecular Mechanisms ◽  
Genetic Model ◽  
Model Organism ◽  
Fruit Fly ◽  
Model Organisms ◽  
Valuable Insight ◽  
Reward Contingency ◽  
Neural Basis ◽  
Operant Task

Maladaptive operant conditioning contributes to development of neuropsychiatric disorders. Candidate genes have been identified that contribute to this maladaptive plasticity, but the neural basis of operant conditioning in genetic model organisms remains poorly understood. The fruit fly Drosophila melanogaster is a versatile genetic model organism that readily forms operant associations with punishment stimuli. However, operant conditioning with a food reward has not been demonstrated in flies, limiting the types of neural circuits that can be studied. Here we present the first sucrose-reinforced operant conditioning paradigm for flies. In the paradigm, flies walk along a Y-shaped track with reward locations at the terminus of each hallway. When flies turn in the reinforced direction at the center of the track, they receive a sucrose reward at the end of the hallway. Only flies that rest early in training learn the reward contingency normally. Flies rewarded independently of their behavior do not form a learned association but have the same amount of rest as trained flies, showing that rest is not driven by learning. Optogenetically-induced sleep does not promote learning, indicating that sleep itself is not sufficient for learning the operant task. We validated the sensitivity of this assay to detect the effect of genetic manipulations by testing the classic learning mutant dunce. Dunce flies are learning-impaired in the Y-Track task, indicating a likely role for cAMP in the operant coincidence detector. This novel training paradigm will provide valuable insight into the molecular mechanisms of disease and the link between sleep and learning.

scholarly journals Author response: The neural basis for a persistent internal state in Drosophila females

2020 ◽  
Author(s):  
David Deutsch ◽  
Diego Pacheco ◽  
Lucas Encarnacion-Rivera ◽  
Talmo Pereira ◽  
Ramie Fathy ◽  
...  
Keyword(s):  
Internal State ◽  
Author Response ◽  
Neural Basis

scholarly journals Gustatory responses in macaque monkeys revealed with fMRI: Comments on taste, taste preference, and internal state

NeuroImage ◽  
2019 ◽  
Vol 184 ◽  
pp. 932-942 ◽  
Author(s):  
Peter M. Kaskan ◽  
Aaron M. Dean ◽  
Mark A. Nicholas ◽  
Andrew R. Mitz ◽  
Elisabeth A. Murray
Keyword(s):  
Internal State ◽  
Taste Preference ◽  
Macaque Monkeys

scholarly journals Electrophysiological Responses from the Human Tongue to the Six Taste Qualities and Their Relationships with PROP Taster Status

Nutrients ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2017
Author(s):  
Melania Melis ◽  
Giorgia Sollai ◽  
Mariano Mastinu ◽  
Danilo Pani ◽  
Piero Cosseddu ◽  
...  
Keyword(s):  
Taste Quality ◽  
Taste Perception ◽  
Gustatory System ◽  
Dietary Preferences ◽  
Human Tongue ◽  
Electrophysiological Recordings ◽  
Electrophysiological Responses ◽  
Individual Variations ◽  
The Relationship

Taste buds containing receptor cells that primarily detect one taste quality provide the basis for discrimination across taste qualities. The molecular receptor multiplicity and the interactions occurring between bud cells encode information about the chemical identity, nutritional value, and potential toxicity of stimuli before transmitting signals to the hindbrain. PROP (6-n-propylthiouracil) tasting is widely considered a marker for individual variations of taste perception, dietary preferences, and health. However, controversial data have been reported. We present measures of the peripheral gustatory system activation in response to taste qualities by electrophysiological recordings from the tongue of 39 subjects classified for PROP taster status. The waveform of the potential variation evoked depended on the taste quality of the stimulus. Direct relationships between PROP sensitivity and electrophysiological responses to taste qualities were found. The largest and fastest responses were recorded in PROP super-tasters, who had the highest papilla density, whilst smaller and slower responses were found in medium tasters and non-tasters with lower papilla densities. The intensities perceived by subjects of the three taster groups correspond to their electrophysiological responses for all stimuli except NaCl. Our results show that each taste quality can generate its own electrophysiological fingerprint on the tongue and provide direct evidence of the relationship between general taste perception and PROP phenotype.

scholarly journals The neural basis for a persistent internal state in Drosophila females

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
David Deutsch ◽  
Diego Pacheco ◽  
Lucas Encarnacion-Rivera ◽  
Talmo Pereira ◽  
Ramie Fathy ◽  
...  
Keyword(s):  
Neural Activity ◽  
Neural Circuit ◽  
Internal State ◽  
Persistent Activity ◽  
Neural Basis ◽  
Electron Microscopic ◽  
Brain Areas ◽  
Female Behavior ◽  
Specific Subset ◽  
Female Brain

Sustained changes in mood or action require persistent changes in neural activity, but it has been difficult to identify the neural circuit mechanisms that underlie persistent activity and contribute to long-lasting changes in behavior. Here, we show that a subset of Doublesex+ pC1 neurons in the Drosophila female brain, called pC1d/e, can drive minutes-long changes in female behavior in the presence of males. Using automated reconstruction of a volume electron microscopic (EM) image of the female brain, we map all inputs and outputs to both pC1d and pC1e. This reveals strong recurrent connectivity between, in particular, pC1d/e neurons and a specific subset of Fruitless+ neurons called aIPg. We additionally find that pC1d/e activation drives long-lasting persistent neural activity in brain areas and cells overlapping with the pC1d/e neural network, including both Doublesex+ and Fruitless+ neurons. Our work thus links minutes-long persistent changes in behavior with persistent neural activity and recurrent circuit architecture in the female brain.

scholarly journals Relationship Between Taste Perception for Salt and Blood Pressure in Normotensive and Hypertensive Korean Adults (P12-027-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Jayong Chung ◽  
Suyun Lee
Keyword(s):  
Blood Pressure ◽  
Sodium Intake ◽  
Detection Threshold ◽  
Taste Preference ◽  
Recognition Threshold ◽  
Taste Perception ◽  
Hypertensive Patients ◽  
Korean Adults ◽  
Funding Sources ◽  
Salty Taste

Abstract Objectives It is well known that excessive sodium intake increases the risk for developing cardiovascular diseases. Taste perception contributes food choice and may be important in determining nutrient intake. The purpose of this study was to examine the relationship between taste perceptions for salt and blood pressure in Korean adults. Methods Detection and recognition thresholds to salt and salty taste preference to the salty bean sprout soup were measured in healthy adults and hypertensive patients (n = 280). Results Recognition threshold to NaCl was significantly higher in hypertensive females than in normotensive females (0.076% and 0.054%, respectively, P < 0.05), while no such difference was found in males. Further, in females, those with higher tertiles of recognition thresholds had significantly higher levels of DBP as compared to those with lowest tertiles (p for trend < 0.05). Preference scores for salty taste were positively correlated with recognition threshold for salt in females (r = 0.208, P = 0.003). Similarly, liking responses to 0.63% NaCl soup and 1.25% NaCl soup were significantly correlated with recognition threshold for salt in females [r = 0.165 (P = 0.025) and r = 0.191 (P = 0.011), respectively). Interestingly, in females with the highest tertiles of recognition threshold, the liking responses to 1.25% NaCl soup were significantly higher in hypertensive patients than in normotensive controls, but no such relationship were found in females with the lower tertiles of recognition threshold (p for interaction = 0.017), suggesting the altered taste acuity for salt in hypertensive patients significantly affects the taste preference for salt. Both detection threshold and recognition threshold were significantly correlated with the salt usage behavior [r = 0.415 (P = 0.015) and r = 0.263 (P = 0.035), respectively] in hypertensive females. Conclusions Findings from the current study suggest that the taste acuity for salt is altered in hypertensive females, which may influence dietary behavior associated with sodium intake. Further study is warranted to find an effective measures to improve taste acuity in hypertensive patients. Funding Sources This report was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government, NRF-2017R1A2B1009697.

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