The taste and flavour system

2020 ◽  
pp. 192-216
Author(s):  
Edmund T. Rolls
Keyword(s):  
Orbitofrontal Cortex ◽  
Distributed Representation ◽  
Taste System ◽  
System P ◽  
Reward Value

Information is represented in taste regions up to and including the insular primary taste system of what the taste is independent of its reward value and pleasantness with a sparse distributed representation of sweet, salt, bitter, sour and umami inputs. The texture of food in the mouth, including fat texture, is also represented in these areas. The insular taste cortex then projects to the orbitofrontal cortex, in which the reward value and pleasantness of the taste and flavour are represented, with olfactory components included.

The olfactory system

2020 ◽  
pp. 217-231
Author(s):  
Edmund T. Rolls
Keyword(s):  
Olfactory Bulb ◽  
Orbitofrontal Cortex ◽  
Olfactory Receptor ◽  
Olfactory System ◽  
Pyriform Cortex ◽  
System P ◽  
Reward Value

There are 1000 gene-specified olfactory receptor types projecting to the olfactory bulb and then to the olfactory (pyriform) cortex. This processing enables what the odour is to be represented. The olfactory (pyriform) cortex then projects to the orbitofrontal cortex, where the representation is mapped away from a gene-specified space into an odour reward value space, with the orbitofrontal cortex responding for example to the pleasantness of odours including the smell and flavour of food. The mechanism of the transform includes pattern association with stimuli in other modalities, such as the taste and texture of food.

Subjective reward value of visual sexual stimuli is coded in human striatum and orbitofrontal cortex

2020 ◽  
Vol 393 ◽  
pp. 112792
Author(s):  
Sanja Klein ◽  
Onno Kruse ◽  
Charlotte Markert ◽  
Isabell Tapia León ◽  
Jana Strahler ◽  
...  
Keyword(s):  
Orbitofrontal Cortex ◽  
Sexual Stimuli ◽  
Reward Value ◽  
Visual Sexual Stimuli

scholarly journals Covert shift of attention modulates the value encoding in the orbitofrontal cortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Yang Xie ◽  
Chechang Nie ◽  
Tianming Yang
Keyword(s):  
Decision Making ◽  
Eye Movement ◽  
Neuronal Activity ◽  
Orbitofrontal Cortex ◽  
Passive Viewing ◽  
Reward Value ◽  
Winner Take All ◽  
Take All ◽  
Attention Shifts

During value-based decision making, we often evaluate the value of each option sequentially by shifting our attention, even when the options are presented simultaneously. The orbitofrontal cortex (OFC) has been suggested to encode value during value-based decision making. Yet it is not known how its activity is modulated by attention shifts. We investigated this question by employing a passive viewing task that allowed us to disentangle effects of attention, value, choice and eye movement. We found that the attention modulated OFC activity through a winner-take-all mechanism. When we attracted the monkeys’ attention covertly, the OFC neuronal activity reflected the reward value of the newly attended cue. The shift of attention could be explained by a normalization model. Our results strongly argue for the hypothesis that the OFC neuronal activity represents the value of the attended item. They provide important insights toward understanding the OFC’s role in value-based decision making.

scholarly journals Sensory processing in the brain related to the control of food intake

2007 ◽  
Vol 66 (1) ◽  
pp. 96-112 ◽  
Author(s):  
Edmund T. Rolls
Keyword(s):  
Food Intake ◽  
Orbitofrontal Cortex ◽  
Functional Neuroimaging ◽  
Rhesus Macaques ◽  
Human Subjects ◽  
Sensory Properties ◽  
Visual Inputs ◽  
Reward Value ◽  
Frontal Operculum ◽  
Taste And Smell

Complementary neurophysiological recordings in rhesus macaques (Macaca mulatta) and functional neuroimaging in human subjects show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. In the orbitofrontal cortex feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including the human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food that drives food intake. Factors that lead this system to become unbalanced and contribute to overeating and obesity are described.

scholarly journals Reward-specific satiety affects subjective value signals in orbitofrontal cortex during multicomponent economic choice

2021 ◽  
Vol 118 (30) ◽  
pp. e2022650118
Author(s):  
Alexandre Pastor-Bernier ◽  
Arkadiusz Stasiak ◽  
Wolfram Schultz
Keyword(s):  
Orbitofrontal Cortex ◽  
Economic Value ◽  
Revealed Preference ◽  
Value Change ◽  
Neuronal Coding ◽  
Preference Theory ◽  
Subjective Value ◽  
Reward Value ◽  
Value Loss ◽  
Reward Functions

Sensitivity to satiety constitutes a basic requirement for neuronal coding of subjective reward value. Satiety from natural ongoing consumption affects reward functions in learning and approach behavior. More specifically, satiety reduces the subjective economic value of individual rewards during choice between options that typically contain multiple reward components. The unconfounded assessment of economic reward value requires tests at choice indifference between two options, which is difficult to achieve with sated rewards. By conceptualizing choices between options with multiple reward components (“bundles”), Revealed Preference Theory may offer a solution. Despite satiety, choices against an unaltered reference bundle may remain indifferent when the reduced value of a sated bundle reward is compensated by larger amounts of an unsated reward of the same bundle, and then the value loss of the sated reward is indicated by the amount of the added unsated reward. Here, we show psychophysically titrated choice indifference in monkeys between bundles of differently sated rewards. Neuronal chosen value signals in the orbitofrontal cortex (OFC) followed closely the subjective value change within recording periods of individual neurons. A neuronal classifier distinguishing the bundles and predicting choice substantiated the subjective value change. The choice between conventional single rewards confirmed the neuronal changes seen with two-reward bundles. Thus, reward-specific satiety reduces subjective reward value signals in OFC. With satiety being an important factor of subjective reward value, these results extend the notion of subjective economic reward value coding in OFC neurons.

scholarly journals The Architecture of Reward Value Coding in the Human Orbitofrontal Cortex

2010 ◽  
Vol 30 (39) ◽  
pp. 13095-13104 ◽  
Author(s):  
G. Sescousse ◽  
J. Redoute ◽  
J.-C. Dreher
Keyword(s):  
Orbitofrontal Cortex ◽  
Reward Value ◽  
Value Coding

Representation of Umami Taste in the Human Brain

2003 ◽  
Vol 90 (1) ◽  
pp. 313-319 ◽  
Author(s):  
I.E.T. de Araujo ◽  
M. L. Kringelbach ◽  
E. T. Rolls ◽  
P. Hobden
Keyword(s):  
Orbitofrontal Cortex ◽  
Anterior Part ◽  
Monosodium Glutamate ◽  
Blood Oxygenation ◽  
Anterior Cingulate ◽  
Bold Signal ◽  
Taste System ◽  
Umami Taste ◽  
Oxygenation Level ◽  
Cortical Regions

Umami taste stimuli, of which an exemplar is monosodium glutamate (MSG) and which capture what is described as the taste of protein, were shown using functional MRI (fMRI) to activate similar cortical regions of the human taste system to those activated by a prototypical taste stimulus, glucose. These taste regions included the insular/opercular cortex and the caudolateral orbitofrontal cortex. A part of the rostral anterior cingulate cortex (ACC) was also activated. When the nucleotide 0.005 M inosine 5′-monophosphate (IMP) was added to MSG (0.05 M), the blood oxygenation-level dependent (BOLD) signal in an anterior part of the orbitofrontal cortex showed supralinear additivity; this may reflect the subjective enhancement of umami taste that has been described when IMP is added to MSG. These results extend to humans previous studies in macaques showing that single neurons in these taste cortical areas can be tuned to umami stimuli.

The orbitofrontal cortex, amygdala, reward value, and emotion

2020 ◽  
pp. 379-446
Author(s):  
Edmund T. Rolls
Keyword(s):  
Neural Networks ◽  
Decision Making ◽  
Basal Ganglia ◽  
Anterior Cingulate Cortex ◽  
Orbitofrontal Cortex ◽  
Brain Region ◽  
Anterior Cingulate ◽  
Rule Based ◽  
Reward Value ◽  
Trial Object

The orbitofrontal cortex receives from the ends of all sensory processing systems, and converts these representations of what the stimulus is into representations of their reward value. The orbitofrontal cortex is therefore a key brain region in emotions, which can be defined as states elicited by rewards and punishers. Indeed, orbitofrontal cortex activations are linearly related to the subjectively reported pleasantness of stimuli. The orbitofrontal cortex then projects this reward value information to other structures, which implement behavioural output, such as the anterior cingulate cortex, and the basal ganglia. A key computational capacity of the orbitofrontal cortex is one-trial object-reward associations, which are rule-based, and enable primates including humans to change their rewarded behaviour very rapidly. Decision-making using attractor neural networks is described.

scholarly journals The neural dynamics of reward value and risk coding in the human orbitofrontal cortex

Brain ◽  
2016 ◽  
Vol 139 (4) ◽  
pp. 1295-1309 ◽  
Author(s):  
Yansong Li ◽  
Giovanna Vanni-Mercier ◽  
Jean Isnard ◽  
François Mauguière ◽  
Jean-Claude Dreher
Keyword(s):  
Orbitofrontal Cortex ◽  
Neural Dynamics ◽  
Reward Value

Neuronal Activity in Primate Orbitofrontal Cortex Reflects the Value of Time

2005 ◽  
Vol 94 (4) ◽  
pp. 2457-2471 ◽  
Author(s):  
Matthew R. Roesch ◽  
Carl R. Olson
Keyword(s):  
Neuronal Activity ◽  
Orbitofrontal Cortex ◽  
Large Reward ◽  
Value Of Time ◽  
Extrinsic Factor ◽  
Fixed Size ◽  
Extrinsic Factors ◽  
Short Delay ◽  
Reward Value ◽  
Saccade Task

Neurons in monkey orbitofrontal cortex (OF) are known to respond to reward-predicting cues with a strength that depends on the value of the predicted reward as determined 1) by intrinsic attributes including size and quality and 2) by extrinsic factors including the monkey's state of satiation and awareness of what other rewards are currently available. We pose here the question whether another extrinsic factor critical to determining reward value—the delay expected to elapse before delivery—influences neuronal activity in OF. To answer this question, we recorded from OF neurons while monkeys performed a memory-guided saccade task in which a cue presented early in each trial predicted whether the delay before the monkey could respond and receive a reward of fixed size would be short or long. OF neurons tended to fire more strongly in response to a cue predicting a short delay. The tendency to fire more strongly in anticipation of a short delay was correlated across neurons with the tendency to fire more strongly before a large reward. We conclude that neuronal activity in OF represents the time-discounted value of the expected reward.

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