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 Eye-movement reinstatement and neural reactivation during mental imagery

2017 ◽  
Author(s):  
Michael B. Bone ◽  
Marie St-Laurent ◽  
Christa Dang ◽  
Douglas A. McQuiggan ◽  
Jennifer D. Ryan ◽  
...  
Keyword(s):  
Eye Movement ◽  
Mental Imagery ◽  
Brain Activity ◽  
Healthy Human ◽  
Supportive Role ◽  
Constructive Process ◽  
Human Participants ◽  
Multivariate Pattern ◽  
With Memory

AbstractHalf a century ago, Donald Hebb posited that mental imagery is a constructive process that emulates perception. Specifically, Hebb claimed that visual imagery results from the reactivation of neural activity associated with viewing images. He also argued that neural reactivation and imagery benefit from the re-enactment of eye movement patterns that first occurred at viewing (fixation reinstatement). To investigate these claims, we applied multivariate pattern analyses to functional MRI (fMRI) and eye-tracking data collected while healthy human participants repeatedly viewed and visualized complex images. We observed that the specificity of neural reactivation correlated positively with vivid imagery and with memory for stimulus image details. Moreover, neural reactivation correlated positively with fixation reinstatement, meaning that image-specific eye movements accompanied image-specific patterns of brain activity during visualization. These findings support the conception of mental imagery as a simulation of perception, and provide evidence of the supportive role of eye-movement in neural reactivation.

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 Shared and Independent Neural Representation Between Visual Perception and Mental Imagery

2021 ◽  
Author(s):  
Yingying Huang ◽  
Frank Pollick ◽  
Ming Liu ◽  
Delong Zhang
Keyword(s):  
Visual Perception ◽  
Mental Imagery ◽  
Activity Patterns ◽  
Neural Representation ◽  
Gabor Features ◽  
Visual Areas ◽  
Neural Substrate ◽  
Early Visual Cortex ◽  
Human Participants ◽  
Insight Into

Abstract Visual mental imagery and visual perception have been shown to share a hierarchical topological visual structure of neural representation. Meanwhile, many studies have reported a dissociation of neural substrate between mental imagery and perception in function and structure. However, we have limited knowledge about how the visual hierarchical cortex involved into internally generated mental imagery and perception with visual input. Here we used a dataset from previous fMRI research (Horikawa & Kamitani, 2017), which included a visual perception and an imagery experiment with human participants. We trained two types of voxel-wise encoding models, based on Gabor features and activity patterns of high visual areas, to predict activity in the early visual cortex (EVC, i.e., V1, V2, V3) during perception, and then evaluated the performance of these models during mental imagery. Our results showed that during perception and imagery, activities in the EVC could be independently predicted by the Gabor features and activity of high visual areas via encoding models, which suggested that perception and imagery might share neural representation in the EVC. We further found that there existed a Gabor-specific and a non-Gabor-specific neural response pattern to stimuli in the EVC, which were shared by perception and imagery. These findings provide insight into mechanisms of how visual perception and imagery shared representation in the EVC.

scholarly journals A Distinct Role of the Temporal-Parietal Junction in Predicting Socially Guided Decisions

Science ◽  
2012 ◽  
Vol 337 (6090) ◽  
pp. 109-111 ◽  
Author(s):  
R. McKell Carter ◽  
Daniel L. Bowling ◽  
Crystal Reeck ◽  
Scott A. Huettel
Keyword(s):  
Pattern Analysis ◽  
Multivariate Pattern Analysis ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Incentive Compatible ◽  
Future Behavior ◽  
Human Participants ◽  
Multivariate Pattern ◽  
Distinct Role

To make adaptive decisions in a social context, humans must identify relevant agents in the environment, infer their underlying strategies and motivations, and predict their upcoming actions. We used functional magnetic resonance imaging, in conjunction with combinatorial multivariate pattern analysis, to predict human participants’ subsequent decisions in an incentive-compatible poker game. We found that signals from the temporal-parietal junction provided unique information about the nature of the upcoming decision, and that information was specific to decisions against agents who were both social and relevant for future behavior.

scholarly journals Nonlinear relationship between multimodal adrenergic responses and local dendritic activity in primary sensory cortices

2019 ◽  
Author(s):  
Yair Deitcher ◽  
Yonatan Leibner ◽  
Sara Kutzkel ◽  
Neta Zylbermann ◽  
Michael London
Keyword(s):  
Barrel Cortex ◽  
Adrenergic System ◽  
Somatosensory Stimulation ◽  
Phasic Activity ◽  
Sensory Stimuli ◽  
Two Photon ◽  
Axonal Projections ◽  
Sensory Cortices ◽  
Visual Cortices ◽  
The Relationship

AbstractThe axonal projections of the adrenergic system to the neocortex, originating from the locus coeruleus (LC), form a dense network. These axons release the neuromodulator norepinephrine (NE) which is involved in many cognitive functions such as attention, arousal, and working memory. Using two-photon Ca2+ imaging of NE axons in the cortex of awake mice, we investigated what drives their phasic activity. We discovered that NE axons in the primary somatosensory cortex responded robustly and reliably to somatosensory stimulation. Surprisingly, the same axons also responded to stimuli of other modalities (auditory and visual). Similar responses to all three modalities were observed in the primary visual cortex as well. These results indicate that phasic responses of NE axons to sensory stimuli provide a robust multimodal signal. However, despite the robustness, we also noticed consistent variations in the data. For example, responses to whisker stimulations were larger than to auditory and visual stimulations in both the barrel and the visual cortices. To test whether the variations in NE axonal responses can carry behaviorally meaningful information, we trained mice in an associative auditory fear conditioning paradigm. We found that following conditioning the response of NE axons increased only for CS+, namely the signal undergoes experience-dependent plasticity and is specific to meaningful sounds. To test if variations in NE axonal responses can differentially affect the cortical microcircuit, we used dual-color two-photon Ca2+ imaging and studied the relationship between the activity of NE axons and local dendrites. We found dendritic Ca2+ signals in barrel cortex in response to auditory stimuli, but these responses were variable and unreliable. Strikingly, the probability of such dendritic signals increased nonlinearly with the Ca2+ signals of NE axons. Our results demonstrate that the phasic activity of the noradrenergic neurons may serve as a robust multimodal and plastic signal in sensory cortices. Furthermore, the variations in the NE axonal activity carry behaviorally meaningful signals and can predict the probability of local dendritic Ca2+ events.

scholarly journals Decoding images in the mind’s eye: The temporal dynamics of visual imagery

2019 ◽  
Author(s):  
Sophia M. Shatek ◽  
Tijl Grootswagers ◽  
Amanda K. Robinson ◽  
Thomas A. Carlson
Keyword(s):  
Mental Imagery ◽  
Visual Processing ◽  
Temporal Dynamics ◽  
Brain Activity ◽  
Brain Regions ◽  
Time Resolved ◽  
Santa Claus ◽  
Physical Stimuli ◽  
Multivariate Pattern ◽  
The Mind

AbstractMental imagery is the ability to generate images in the mind in the absence of sensory input. Both perceptual visual processing and internally generated imagery engage large, overlapping networks of brain regions. However, it is unclear whether they are characterized by similar temporal dynamics. Recent magnetoencephalography work has shown that object category information was decodable from brain activity during mental imagery, but the timing was delayed relative to perception. The current study builds on these findings, using electroencephalography to investigate the dynamics of mental imagery. Sixteen participants viewed two images of the Sydney Harbour Bridge and two images of Santa Claus. On each trial, they viewed a sequence of the four images and were asked to imagine one of them, which was cued retroactively by its temporal location in the sequence. Time-resolved multivariate pattern analysis was used to decode the viewed and imagined stimuli. Our results indicate that the dynamics of imagery processes are more variable across, and within, participants compared to perception of physical stimuli. Although category and exemplar information was decodable for viewed stimuli, there were no informative patterns of activity during mental imagery. The current findings suggest stimulus complexity, task design and individual differences may influence the ability to successfully decode imagined images. We discuss the implications of these results for our understanding of the neural processes underlying mental imagery.

scholarly journals Neural substrates of intrinsically motivated perseverance in adolescents and adults

2020 ◽  
Author(s):  
Sarah M. Tashjian ◽  
Adriana Galván
Keyword(s):  
Negative Feedback ◽  
Performance Feedback ◽  
Relevant Information ◽  
Neural Substrates ◽  
Value Systems ◽  
Neural Systems ◽  
Adolescents And Adults ◽  
The Face ◽  
Human Participants ◽  
Multivariate Pattern

Perseverance decisions rely on the ability to motivate behavior despite failure. Although perseverance is widely recognized to confer psychological and achievement benefits, there is a dearth of understanding regarding neural systems underpinning intrinsically motivated perseverance. This study elicited perseverance decisions in 99 human participants ages 13-30 (61 females) using a new task and fMRI. Perseverers (versus non-perseverers) evinced increased neural response in the medial prefrontal cortex (mPFC) to goal-relevant information (performance feedback versus monetary reward) and positively valenced information (positive versus negative performance feedback). Multivariate pattern analysis revealed representation of positive and negative feedback were more similar for perseverers, but representation of positive feedback and money did not distinguish the groups. Younger participants were less likely to persevere and recruited the superior frontal gyrus (SFG) to a greater extent after negative feedback. These findings suggest perseverance targets motivational and value systems important for propelling action in the face of failure.

scholarly journals Alertness modulates perceptual decision-making

2020 ◽  
Author(s):  
Sridhar R. Jagannathan ◽  
Corinne A. Bareham ◽  
Tristan A. Bekinschtein
Keyword(s):  
Decision Making ◽  
Neural Dynamics ◽  
External Information ◽  
Perceptual Decision Making ◽  
Drift Diffusion ◽  
Perceptual Decision ◽  
Diffusion Modelling ◽  
Human Participants ◽  
Multivariate Pattern ◽  
Work Done

ABSTRACTThe ability to make decisions based on external information, prior knowledge and context is a crucial aspect of cognition and it may determine the success and survival of an organism. Despite extensive and detailed work done on the decision making mechanisms, the understanding of the effects of arousal remain limited. Here we characterise behavioural and neural dynamics of decision making in awake and low alertness periods to characterise the compensatory signatures of the cognitive system when arousal decreases. We used an auditory tone-localisation task in human participants under conditions of fully awake and low arousal. Behavioural dynamics analyses using psychophysics, signal detection theory and drift-diffusion modelling showed slower responses, decreased performance and a lower rate of evidence accumulation due to alertness fluctuations. To understand the modulation in neural dynamics we used multivariate pattern analysis (decoding), identifying a shift in the temporal and spatial signatures involved. Finally, we connected the computational parameters identified in the drift diffusion modelling with neural signatures, capturing the effective lag exerted by alertness in the neurocognitive system underlying decision making. These results define the reconfiguration of the brain networks, regions and dynamics needed for the implementation of perceptual decision making, revealing mechanisms of resilience of cognition when challenged by decreases in arousal.

Fear in the theater of the mind: Mental imagery of conditioned stimuli undergo the acquisition and generalization of differential fear conditioning

2021 ◽  
Author(s):  
Lauryn Burleigh ◽  
Xinrui Jiang ◽  
Steven G Greening
Keyword(s):  
Fear Conditioning ◽  
Mental Imagery ◽  
Differential Conditioning ◽  
Post Traumatic Stress ◽  
Conditioned Stimuli ◽  
Healthy Human ◽  
Post Traumatic ◽  
Human Participants ◽  
The Mind ◽  
Theater Of The Mind

Many symptoms of anxiety and post-traumatic stress disorder are elicited by mental imagery of a conditioned stimulus (CS). Yet, little is known about how visual imagery of CSs interacts with the acquisition of differential fear conditioning. Across three experiments (n1=33, n2=27, n3=26), we observed that healthy human participants acquired differential fear conditioning to both viewed and imagined percepts serving as the conditioned stimuli as measured via self-reported fear and the skin conductance response (SCR). Additionally, this differential conditioning generalized across CS percept modalities, such that differential conditioning acquired to visual percepts generalized to the corresponding imagined percepts and vice versa. This is novel evidence that perceived and imagined stimuli engage learning processes in very similar ways and is consistent with theory that mental imagery is depictive and recruits neural resources shared with visual perception. Our findings also provide new insight into the mechanisms of anxiety and related disorders.

Sign in / Sign up

Export Citation Format

Share Document