scholarly journals Overlapping Representation of Basic Tastes in the Human Gustatory Cortex

2021 ◽  
Author(s):  
Du Zhang ◽  
Xiaoxiao Wang ◽  
Yanming Wang ◽  
Benedictor Alexander Nguchu ◽  
Zhoufang Jiang ◽  
...  
Keyword(s):  
Fundamental Property ◽  
Insular Cortex ◽  
Taste Preference ◽  
Topological Representation ◽  
Activation Patterns ◽  
Gustatory Cortex ◽  
Taste Response ◽  
Neural Activities ◽  
Sensory Cortices ◽  
Multivariate Pattern

The topological representation is a fundamental property of human primary sensory cortices. The human gustatory cortex (GC) responds to the five basic tastes: bitter, salty, sweet, umami, and sour. However, the topological representation of the human gustatory cortex remains controversial. Through functional magnetic resonance imaging(fMRI) measurements of human responses to the five basic tastes, the current study aimed to delineate the taste representations within the GC. During the scanning, the volunteers tasted solutions of the five basic tastes, then washed their mouths with the tasteless solution. The solutions were then sucked from the volunteers' mouths, eliminating the action of swallowing. The results showed that the bilateral mid-insula activated most during the taste task, and the active areas were mainly in the precentral and central insular sulcus. However, the regions responding to the five basic tastes are substantially overlapped, and the analysis of contrasts between each taste response and the averaged response to the remaining tastes does not report any significant results. Furthermore, in the gustatory insular cortex, the multivariate pattern analysis (MVPA) was unable to distinguish the activation patterns of the basic tastes, suggesting the possibility of weakly clustered distribution of the taste-preference neural activities in the human insular cortex. In conclusion, the presented results suggest overlapping representations of the basic tastes in the human gustatory insular cortex.

scholarly journals Information-based taste maps in insular cortex are shaped by stimulus concentration

2019 ◽  
Author(s):  
E Porcu ◽  
KM Benz ◽  
F Ball ◽  
C Tempelmann ◽  
M Hanke ◽  
...  
Keyword(s):  
Complex Function ◽  
Insular Cortex ◽  
Population Level ◽  
Ingestive Behavior ◽  
Current Evidence ◽  
High Concentration ◽  
Potential Harm ◽  
Taste Processing ◽  
Human Participants ◽  
Multivariate Pattern

AbstractTaste processing is an essential ability in all animals signaling potential harm or benefit of ingestive behavior. Although the peripheral taste coding is well understood, current evidence for central taste processing remains contradictory. To address this issue, human participants judged pleasantness and intensity of low and high-concentration tastes (salty, sweet, sour, bitter) in two fMRI-experiments. High-resolution fMRI and multivariate pattern analysis were used to characterize taste-related informational content in human gustatory cortex (GC). Clusters within GC were narrowly tuned to specific tastants consistently across tasks. Importantly, taste concentrations completely altered the spatial layout of putative taste-specific maps with distinct, non-overlapping patterns for each taste category at different concentration levels. Together, our results point at population-level representations in human GC as a complex function of taste category and concentration.

scholarly journals Associative learning changes cross-modal representations in the gustatory cortex

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Roberto Vincis ◽  
Alfredo Fontanini
Keyword(s):  
Associative Learning ◽  
Neural Representation ◽  
Sensory Cortex ◽  
Gustatory Cortex ◽  
Primary Sensory Cortex ◽  
Sensory Modalities ◽  
Before And After ◽  
Olfactory Stimuli ◽  
Sensory Cortices ◽  
Single Modality

A growing body of literature has demonstrated that primary sensory cortices are not exclusively unimodal, but can respond to stimuli of different sensory modalities. However, several questions concerning the neural representation of cross-modal stimuli remain open. Indeed, it is poorly understood if cross-modal stimuli evoke unique or overlapping representations in a primary sensory cortex and whether learning can modulate these representations. Here we recorded single unit responses to auditory, visual, somatosensory, and olfactory stimuli in the gustatory cortex (GC) of alert rats before and after associative learning. We found that, in untrained rats, the majority of GC neurons were modulated by a single modality. Upon learning, both prevalence of cross-modal responsive neurons and their breadth of tuning increased, leading to a greater overlap of representations. Altogether, our results show that the gustatory cortex represents cross-modal stimuli according to their sensory identity, and that learning changes the overlap of cross-modal representations.

scholarly journals Differentiation of Visceral and Cutaneous Pain in the Human Brain

2003 ◽  
Vol 89 (6) ◽  
pp. 3294-3303 ◽  
Author(s):  
Irina A. Strigo ◽  
Gary H. Duncan ◽  
Michel Boivin ◽  
M. Catherine Bushnell
Keyword(s):  
Primary Motor Cortex ◽  
Visceral Pain ◽  
Insular Cortex ◽  
Anterior Cingulate ◽  
Contact Heat ◽  
Activation Patterns ◽  
Cutaneous Pain ◽  
Muscle Tissues ◽  
Balloon Distention ◽  
Parietal Cortices

The widespread convergence of information from visceral, cutaneous, and muscle tissues onto CNS neurons invites the question of how to identify pain as being from the viscera. Despite referral of visceral pain to cutaneous areas, individuals regularly distinguish cutaneous and visceral pain and commonly have contrasting behavioral reactions to each. Our study addresses this dilemma by directly comparing human neural processing of intensity-equated visceral and cutaneous pain. Seven subjects underwent fMRI scanning during visceral and cutaneous pain produced by balloon distention of the distal esophagus and contact heat on the midline chest. Stimulus intensities producing nonpainful and painful sensations, interleaved with rest periods, were presented in each functional run. Analyses compared painful to nonpainful conditions. A similar neural network, including secondary somatosensory and parietal cortices, thalamus, basal ganglia, and cerebellum, was activated by visceral and cutaneous painful stimuli. However, cutaneous pain evoked higher activation bilaterally in the anterior insular cortex. Further, cutaneous but not esophageal pain activated ventrolateral prefrontal cortex, despite higher affective scores for visceral pain. Visceral but not cutaneous pain activated bilateral inferior primary somatosensory cortex, bilateral primary motor cortex, and a more anterior locus within anterior cingulate cortex. Our results reveal a common cortical network subserving cutaneous and visceral pain that could underlie similarities in the pain experience. However, we also observed differential activation patterns within insular, primary somatosensory, motor, and prefrontal cortices that may account for the ability to distinguish visceral and cutaneous pain as well as the differential emotional, autonomic and motor responses associated with these different sensations.

Revisiting the Role of the Fusiform Face Area in Expertise

2016 ◽  
Vol 28 (9) ◽  
pp. 1345-1357 ◽  
Author(s):  
Merim Bilalić
Keyword(s):  
Pattern Analysis ◽  
Spatial Relations ◽  
Fusiform Face Area ◽  
Multivariate Pattern Analysis ◽  
Multiple Objects ◽  
Activation Patterns ◽  
Face Area ◽  
Single Category ◽  
Multivariate Pattern

The fusiform face area (FFA) is considered to be a highly specialized brain module because of its central importance for face perception. However, many researchers claim that the FFA is a general visual expertise module that distinguishes between individual examples within a single category. Here, I circumvent the shortcomings of some previous studies on the FFA controversy by using chess stimuli, which do not visually resemble faces, together with more sensitive methods of analysis such as multivariate pattern analysis. I also extend the previous research by presenting chess positions, complex scenes with multiple objects, and their interrelations to chess experts and novices as well as isolated chess objects. The first experiment demonstrates that chess expertise modulated the FFA activation when chess positions were presented. In contrast, single chess objects did not produce different activation patterns among experts and novices even when the multivariate pattern analysis was used. The second experiment focused on the single chess objects and featured an explicit task of identifying the chess objects but failed to demonstrate expertise effects in the FFA. The experiments provide support for the general expertise view of the FFA function but also extend the scope of our understanding about the function of the FFA. The FFA does not merely distinguish between different exemplars within the same category of stimuli. More likely, it parses complex multiobject stimuli that contain numerous functional and spatial relations.

scholarly journals Evidence for embodied predictive coding: the anterior insula coordinates cortical processing of tactile deviancy

2015 ◽  
Author(s):  
Micah Allen ◽  
Francesca Fardo ◽  
Martin Dietz ◽  
Hauke F Hillebrandt ◽  
Geraint Rees ◽  
...  
Keyword(s):  
Brain Activity ◽  
Predictive Coding ◽  
Insular Cortex ◽  
Body Awareness ◽  
Self Awareness ◽  
Cortical Processing ◽  
Subjective Ratings ◽  
Tactile Stimuli ◽  
Sensory Cortices ◽  
Healthy Participants

Embodied awareness is the pervasive, multimodal self-awareness that is thought to form the foundation of emotion. This awareness was recently proposed to rely on the anterior insular cortex (AIC) comparing expected and actual bodily signals arising in prefrontal and sensory cortices. To investigate this possibility in the somatosensory domain, we measured brain activity using functional magnetic resonance imaging while healthy participants discriminated tactile stimuli in a roving oddball design. Dynamic Causal Modelling revealed that unexpected stimuli increased the strength of forward connections in a caudal to rostral ascending hierarchy from thalamic and somatosensory regions towards insula, cingulate and prefrontal cortices, consistent with hierarchical predictive coding. Within this feed-forward flow of neural coupling, the AIC increased both forwards and backwards connections with prefrontal and somatosensory cortex, supporting a comparator role. Further, we found that greater prefrontal to AIC connectivity predicted subjective ratings of stimulus discrimination difficulty. These results are interpreted in light of embodied predictive coding, suggesting that the AIC coordinates global cortical processing of tactile changes to support body awareness.

scholarly journals The Common Time Course of Memory Processes Revealed

2018 ◽  
Vol 29 (9) ◽  
pp. 1463-1474 ◽  
Author(s):  
John R. Anderson ◽  
Jelmer P. Borst ◽  
Jon M. Fincham ◽  
Avniel Singh Ghuman ◽  
Caitlin Tenison ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Time Course ◽  
Markov Models ◽  
Brain Activation ◽  
Relevant Information ◽  
Sensor Data ◽  
Activation Patterns ◽  
Memory Processes ◽  
Common Time ◽  
Multivariate Pattern

Magnetoencephalography (MEG) was used to compare memory processes in two experiments, one involving recognition of word pairs and the other involving recall of newly learned arithmetic facts. A combination of hidden semi-Markov models and multivariate pattern analysis was used to locate brief “bumps” in the sensor data that marked the onset of different stages of cognitive processing. These bumps identified a separation between a retrieval stage that identified relevant information in memory and a decision stage that determined what response was implied by that information. The encoding, retrieval, decision, and response stages displayed striking similarities across the two experiments in their duration and brain activation patterns. Retrieval and decision processes involve distinct brain activation patterns. We conclude that memory processes for two different tasks, associative recognition versus arithmetic retrieval, follow a common spatiotemporal neural pattern and that both tasks have distinct retrieval and decision stages.

scholarly journals Decoding Digits and Dice with Magnetoencephalography: Evidence for a Shared Representation of Magnitude

2018 ◽  
Vol 30 (7) ◽  
pp. 999-1010 ◽  
Author(s):  
Lina Teichmann ◽  
Tijl Grootswagers ◽  
Thomas Carlson ◽  
Anina N. Rich
Keyword(s):  
Time Course ◽  
Numerical Cognition ◽  
Pattern Analysis ◽  
Brain Activity ◽  
High Temporal Resolution ◽  
Multivariate Pattern Analysis ◽  
Ongoing Debate ◽  
Activation Patterns ◽  
Magnitude Processing ◽  
Multivariate Pattern

Numerical format describes the way magnitude is conveyed, for example, as a digit (“3”) or Roman numeral (“III”). In the field of numerical cognition, there is an ongoing debate of whether magnitude representation is independent of numerical format. Here, we examine the time course of magnitude processing when using different symbolic formats. We presented participants with a series of digits and dice patterns corresponding to the magnitudes of 1 to 6 while performing a 1-back task on magnitude. Magnetoencephalography offers an opportunity to record brain activity with high temporal resolution. Multivariate pattern analysis applied to magnetoencephalographic data allows us to draw conclusions about brain activation patterns underlying information processing over time. The results show that we can cross-decode magnitude when training the classifier on magnitude presented in one symbolic format and testing the classifier on the other symbolic format. This suggests a similar representation of these numerical symbols. In addition, results from a time generalization analysis show that digits were accessed slightly earlier than dice, demonstrating temporal asynchronies in their shared representation of magnitude. Together, our methods allow a distinction between format-specific signals and format-independent representations of magnitude showing evidence that there is a shared representation of magnitude accessed via different symbols.

scholarly journals Two distinct feedback codes in V1 for ‘real’ and ‘imaginary’ internal experiences

2019 ◽  
Author(s):  
Johanna Bergmann ◽  
Andrew T. Morgan ◽  
Lars Muckli
Keyword(s):  
Mental Imagery ◽  
Physical Reality ◽  
Visual Illusions ◽  
Deep Layers ◽  
Incoming Stimulus ◽  
Sensory Cortices ◽  
Inner World ◽  
Visual Cortices ◽  
Human Participants ◽  
Multivariate Pattern

AbstractVisual illusions and visual imagery are conscious sensory events that lack a corresponding physical input. But while everyday mental imagery feels distinct from incoming stimulus input, visual illusions, like hallucinations, are under limited volitional control and appear indistinguishable from physical reality. Illusions are thought to arise from lower-level processes within sensory cortices. In contrast, imagery involves a wide network of brain areas that recruit early visual cortices for the sensory representation of the imagined stimulus. Here, we combine laminar fMRI brain imaging with psychophysical methods and multivariate pattern analysis to investigate in human participants how seemingly ‘real’ and imaginary non-physical experiences are processed in primary visual cortex (V1). We find that the content of mental imagery is only decodable in deep layers, whereas illusory content is only decodable at superficial depths. This suggests that feedback to the different layers may serve distinct functions: low-level feedback to superficial layers might be responsible for shaping perception-like experiences, while deep-layer feedback might serve the formation of a more malleable ‘inner’ world, separate from ongoing perception.

scholarly journals Macroscopic information-based taste representations in insular cortex are shaped by stimulus concentration

2020 ◽  
Vol 117 (13) ◽  
pp. 7409-7417 ◽  
Author(s):  
Emanuele Porcu ◽  
Karsta M. Benz ◽  
Felix Ball ◽  
Claus Tempelmann ◽  
Michael Hanke ◽  
...  
Keyword(s):  
Complex Function ◽  
Insular Cortex ◽  
Ingestive Behavior ◽  
Current Evidence ◽  
Multivariate Pattern Analysis ◽  
High Concentration ◽  
Potential Harm ◽  
Taste Processing ◽  
Human Participants ◽  
Multivariate Pattern

Taste processing is an essential ability in all animals signaling potential harm or benefit of ingestive behavior. However, current evidence for cortical taste representations remains contradictory. To address this issue, high-resolution functional MRI (fMRI) and multivariate pattern analysis were used to characterize taste-related informational content in human insular cortex, which contains primary gustatory cortex. Human participants judged pleasantness and intensity of low- and high-concentration tastes (salty, sweet, sour, and bitter) in two fMRI experiments on two different days to test for task- and concentration-invariant taste representations. We observed patterns of fMRI activity within insular cortex narrowly tuned to specific tastants consistently across tasks in all participants. Fewer patterns responded to more than one taste category. Importantly, changes in taste concentration altered the spatial layout of putative taste-specific patterns with distinct, almost nonoverlapping patterns for each taste category at different concentration levels. Together, our results point at macroscopic representations in human insular cortex as a complex function of taste category and concentration rather than representations based solely on taste identity.

scholarly journals Neural Pattern Similarity Unveils the Integration of Social Information and Aversive Learning

2020 ◽  
Vol 30 (10) ◽  
pp. 5410-5419
Author(s):  
Irem Undeger ◽  
Renée M Visser ◽  
Andreas Olsson
Keyword(s):  
Inferior Frontal Gyrus ◽  
Learning Task ◽  
Anterior Cingulate ◽  
Neural Activation ◽  
Multivariate Pattern Analysis ◽  
Aversive Learning ◽  
Activation Patterns ◽  
Pattern Similarity ◽  
Making Choices ◽  
Multivariate Pattern

Abstract Attributing intentions to others’ actions is important for learning to avoid their potentially harmful consequences. Here, we used functional magnetic resonance imaging multivariate pattern analysis to investigate how the brain integrates information about others’ intentions with the aversive outcome of their actions. In an interactive aversive learning task, participants (n = 33) were scanned while watching two alleged coparticipants (confederates)—one making choices intentionally and the other unintentionally—leading to aversive (a mild shock) or safe (no shock) outcomes to the participant. We assessed the trial-by-trial changes in participants’ neural activation patterns related to observing the coparticipants and experiencing the outcome of their choices. Participants reported a higher number of shocks, more discomfort, and more anger to shocks given by the intentional player. Intentionality enhanced responses to aversive actions in the insula, anterior cingulate cortex, inferior frontal gyrus, dorsal medial prefrontal cortex, and the anterior superior temporal sulcus. Our findings indicate that neural pattern similarities index the integration of social and threat information across the cortex.

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