Human cortical representation of oral temperature

Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC, United States.
Physiology & Behavior (Impact Factor: 2.98). 01/2008; 92(5):975-84. DOI: 10.1016/j.physbeh.2007.07.004
Source: PubMed


The temperature of foods and fluids is a major factor that determines their pleasantness and acceptability. Studies of nonhuman primates have shown that many neurons in cortical taste areas receive and process not only chemosensory inputs, but oral thermosensory (temperature) inputs as well. We investigated whether changes in oral temperature activate these areas in humans, or middle or posterior insular cortex, the areas most frequently identified for the encoding of temperature information from the human hand. In the fMRI study we identified areas of activation in response to innocuous, temperature-controlled (cooled and warmed, 5, 20 and 50 degrees C) liquid introduced into the mouth. The oral temperature stimuli activated the insular taste cortex (identified by glucose taste stimuli), a part of the somatosensory cortex, the orbitofrontal cortex, the anterior cingulate cortex, and the ventral striatum. Brain regions where activations correlated with the pleasantness ratings of the oral temperature stimuli included the orbitofrontal cortex and pregenual cingulate cortex. We conclude that a network of taste- and reward-responsive regions of the human brain is also activated by intra-oral thermal stimulation, and that the pleasant subjective states elicited by oral thermal stimuli are correlated with the activations in the orbitofrontal cortex and pregenual cingulate cortex. Thus the pleasantness of oral temperature is represented in brain regions shown in previous studies to represent the pleasantness of the taste and flavour of food. Bringing together these different oral representations in the same brain regions may enable particular combinations to influence the pleasantness of foods.

Download full-text


Available from: Francis Mcglone
  • Source
    • "Interoception, pain, or emphatic feeling, but also awareness of body movement and emotions as well as speech, have been correlated with activations in the insular cortex (Craig, 2009). Thermal, (Craig et al., 2000; Guest et al., 2007), 0306-4522/Ó 2014 IBRO. Published by Elsevier Ltd. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In humans the identification of the primary gustatory cortex (PGC) is still under debate. Neuroimaging studies indicate Insula and overlying opercula as the best candidates but the exact position of the PGT within this region is not entirely clear. Moreover, inconsistencies appear when comparing results from studies using functional magnetic resonance imaging (FMRI), and gustatory event-related-potentials (gERP), or gustatory event-related magnetic fields (gERMF). fMRI indicates activations in the anterior part of the Insula and frontal operculum, while gERP and/or gERMF indicate activations at the transition between the parietal operculum and insula in its posterior part. Here it is important to note that for gERP and gERMF temporal and spatial characteristics of the stimulus must be well controlled to evoke a useful brain response. In the present study gERMF and gERP were recorded simultaneously using a whole-head system with 249 magnetometers and 32 electrodes, respectively; taste stimuli were applied using a stimulator providing excellent temporal and spatial control of the stimulus. Separate ERP and ERMF averaged waveforms were derived time-locked to the onset of the taste stimuli. The source analysis for the early time range revealed activity in the left and right anterior and mid part of the insula, where in the later time range the sources were located more in the posterior part of the insula.
    Full-text · Article · May 2014 · Neuroscience
  • Source
    • "In addition to sensation of pleasant warm cutaneous stimuli, representations of a number of other pleasant stimuli are described in the medial-orbitofrontal cortex and pregenual cingulate cortex. These include oral warmth (Guest et al., 2007), the attractiveness "
    [Show abstract] [Hide abstract]
    ABSTRACT: Current theories suggest that the brain is the sole source of mental illness. However, affective disorders, and major depressive disorder (MDD) in particular, may be better conceptualized as brain-body disorders that involve peripheral systems as well. This perspective emphasizes the embodied, multifaceted physiology of well-being, and suggests that afferent signals from the body may contribute to cognitive and emotional states. In this review, we focus on evidence from preclinical and clinical studies suggesting that afferent thermosensory signals contribute to well-being and depression. Although thermoregulatory systems have traditionally been conceptualized as serving primarily homeostatic functions, increasing evidence suggests neural pathways responsible for regulating body temperature may be linked more closely with emotional states than previously recognized, an affective warmth hypothesis. Human studies indicate that increasing physical warmth activates brain circuits associated with cognitive and affective functions, promotes interpersonal warmth and prosocial behavior, and has antidepressant effects. Consistent with these effects, preclinical studies in rodents demonstrate that physical warmth activates brain serotonergic neurons implicated in antidepressant-like effects. Together, these studies suggest that (1) thermosensory pathways interact with brain systems that control affective function, (2) these pathways are dysregulated in affective disorders, and (3) activating warm thermosensory pathways promotes a sense of well-being and has therapeutic potential in the treatment of affective disorders.
    Full-text · Article · Jan 2014 · Frontiers in Psychology
  • Source
    • "Villanova et al. (1997) established that cold and warm stimuli in the stomach were consciously perceived and suggests a role for the gastrointestinal tract in perception of temperature. It was subsequently documented that a small (3.5 ml) cold sensation in the mouth increased pleasantness and stimulated areas of the brain associated with reward/pleasure (Guest et al., 2007). It is therefore hypothesized that performance may be improved due to a reduced perception of body temperature and/or via increased central drive resulting from improved sensation of reward/pleasure. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: The purpose of this study was to establish whether sensory factors associated with cold-beverage ingestion exert an ergogenic effect on endurance performance independent of thermoregulatory or cardiovascular factors. Methods: Ten males performed three trials involving 90 min of steady state cycling (SS; 62% VO2max) in the heat (32.1 ± 0.9 °C, 40 ± 2.4% relative humidity) followed by a 4 kJ/kg body mass time trial (TT). During SS, participants consumed an identical volume (260 ± 38 g) of sports beverage (7.4% carbohydrate) every 15 min as either ice slushy (-1 °C; ICE), thermoneutral liquid (37 °C; CON), or thermoneutral liquid consumption with expectorated ice slushy mouthwash (WASH). Results: Rectal temperature, hydration status, heart rate, and skin blood flow were not different between trials. Gastrointestinal (pill) temperature was lower in ICE (35.6 ± 2.7 °C) versus CON (37.4 ± 0.7 °C, p = .05). Heat storage tended to be lower with ICE during SS (14.7 ± 8.4 W.m(-2), p = .08) and higher during TT (68.9 ± 38.6 W.m(-2), p = .03) compared with CON (22.1 ± 6.6 and 31.4 ± 27.6 W.m(-2)). ICE tended to lower the rating of perceived exertion (RPE, 12.9 ± 0.6, p = .05) and improve thermal comfort (TC, 4.5 ± 0.2; p = .01) vs. CON (13.8 ± 1.0 and 5.2 ± 0.2 respectively). WASH RPE (13.0 ± 0.8) and TC (4.8 ± 0.2) tended to be lower versus CON (p = .07 and p = .09 respectively). ICE improved performance (18:28 ± 1:03) compared with CON (20:24 ± 1:46) but not WASH (19:45 ± 1:43). Conclusion: Improved performance with ICE ingestion likely resulted from the creation of a gastrointestinal heat sink, reducing SS heat storage. Although the benefits of cold-beverage consumption are more potent when there is ingestion, improved RPE, TC, and meaningful performance improvement with WASH supports an independent sensory effect of presenting a cold stimulus to the mouth.
    Full-text · Article · Oct 2013 · International Journal of Sport Nutrition and Exercise Metabolism
Show more