scholarly journals Reconstructing imagined letters from early visual cortex reveals tight topographic correspondence between visual mental imagery and perception

2018 ◽  
Author(s):  
Mario Senden ◽  
Thomas Emmerling ◽  
Rick van Hoof ◽  
Martin Frost ◽  
Rainer Goebel
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Visual Imagery ◽  
Subjective Experience ◽  
Fine Tuning ◽  
Machine Learning Techniques ◽  
Visual Mental Imagery ◽  
Topographic Organization ◽  
Early Visual Cortex ◽  
Imagery Data

AbstractVisual mental imagery is the quasi-perceptual experience of “seeing in the mind’s eye”. While a tight correspondence between imagery and perception in terms of subjective experience is well established, their correspondence in terms of neural representations remains insufficiently understood. In the present study, we exploit the high spatial resolution of functional magnetic resonance imaging (fMRI) at 7T, the retinotopic organization of early visual cortex, and machine learning techniques to investigate whether visual imagery of letter shapes preserves the topographic organization of perceived shapes. Sub-millimeter resolution fMRI images were obtained from early visual cortex in six subjects performing visual imagery of four different letter shapes. Predictions of imagery voxel activation patterns based on a population receptive field encoding model and physical letter stimuli provided first evidence in favor of detailed topographic organization. Subsequent visual field reconstructions of imagery data based on the inversion of the encoding model further showed that visual imagery preserves the geometric profile of letter shapes. These results open new avenues for decoding as we show that a denoising autoencoder can be used to pretrain a classifier purely based on perceptual data before fine-tuning it on imagery data. Finally, we show that the autoencoder can project imagery-related voxel activations onto their perceptual counterpart allowing for visually recognizable reconstructions even at the single-trial level. The latter may eventually be utilized for the development of content-based BCI letter-speller systems.

scholarly journals Cortical excitability controls the strength of mental imagery

2016 ◽  
Author(s):  
Rebecca Keogh ◽  
Johanna Bergmann ◽  
Joel Pearson
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Visual Imagery ◽  
Cortical Excitability ◽  
Mental Health Research ◽  
Causative Role ◽  
Mental Images ◽  
Neurophysiological Mechanism ◽  
Early Visual Cortex ◽  
Sensory Imagery

AbstractMental imagery provides an essential simulation tool for remembering the past and planning the future, with its strength affecting both cognition and mental health. Research suggests that neural activity spanning prefrontal, parietal, temporal, and visual areas supports the generation of mental images. Exactly how this network controls the strength of visual imagery remains unknown. Here, brain imaging and transcranial magnetic phosphene data show that lower resting activity and excitability levels in early visual cortex (V1-V3) predict stronger sensory imagery. Electrically decreasing visual cortex excitability using tDCS increases imagery strength, demonstrating a causative role of visual cortex excitability in controlling visual imagery. These data suggest a neurophysiological mechanism of cortical excitability involved in controlling the strength of mental images.

scholarly journals Transient Activity in the Human Calcarine Cortex During Visual-Mental Imagery: An Event-Related fMRI Study

2000 ◽  
Vol 12 (supplement 2) ◽  
pp. 15-23 ◽  
Author(s):  
Isabelle Klein ◽  
Anne-Lise Paradis ◽  
Jean-Baptiste Poline ◽  
Stephen M. Kosslyn ◽  
Denis Le Bihan
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Mental Imagery ◽  
Visual Imagery ◽  
Mental Image ◽  
Functional Magnetic Resonance ◽  
Visual Mental Imagery ◽  
Fmri Study ◽  
Transient Activity ◽  
Imagery Processing

Although it is largely accepted that visual-mental imagery and perception draw on many of the same neural structures, the existence and nature of neural processing in the primary visual cortex (or area V1) during visual imagery remains controversial. We tested two general hypotheses: The first was that V1 is activated only when images with many details are formed and used, and the second was that V1 is activated whenever images are formed, even if they are not necessarily used to perform a task. We used event-related functional magnetic resonance imaging (ER-fMRI) to detect and characterize the activity in the calcarine sulcus (which contains the primary visual cortex) during single instances of mental imagery. The results revealed reproducible transient activity in this area whenever participants generated or evaluated a mental image. This transient activity was strongly enhanced when participants evaluated characteristics of objects, whether or not details actually needed to be extracted from the image to perform the task. These results show that visual imagery processing commonly involves the earliest stages of the visual system.

When is early visual cortex activated during visual mental imagery?

2003 ◽  
Vol 129 (5) ◽  
pp. 723-746 ◽  
Author(s):  
Stephen M. Kosslyn ◽  
William L. Thompson
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Visual Mental Imagery ◽  
Early Visual Cortex

scholarly journals Cortical excitability controls the strength of mental imagery

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Rebecca Keogh ◽  
Johanna Bergmann ◽  
Joel Pearson
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Visual Imagery ◽  
Cortical Excitability ◽  
Mental Health Research ◽  
Causative Role ◽  
Mental Images ◽  
Neurophysiological Mechanism ◽  
Early Visual Cortex ◽  
Sensory Imagery

Mental imagery provides an essential simulation tool for remembering the past and planning the future, with its strength affecting both cognition and mental health. Research suggests that neural activity spanning prefrontal, parietal, temporal, and visual areas supports the generation of mental images. Exactly how this network controls the strength of visual imagery remains unknown. Here, brain imaging and transcranial magnetic phosphene data show that lower resting activity and excitability levels in early visual cortex (V1-V3) predict stronger sensory imagery. Further, electrically decreasing visual cortex excitability using tDCS increases imagery strength, demonstrating a causative role of visual cortex excitability in controlling visual imagery. Together, these data suggest a neurophysiological mechanism of cortical excitability involved in controlling the strength of mental images.

scholarly journals Reconstructing imagined letters from early visual cortex reveals tight topographic correspondence between visual mental imagery and perception

2019 ◽  
Vol 224 (3) ◽  
pp. 1167-1183 ◽  
Author(s):  
Mario Senden ◽  
Thomas C. Emmerling ◽  
Rick van Hoof ◽  
Martin A. Frost ◽  
Rainer Goebel
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Visual Mental Imagery ◽  
Early Visual Cortex

scholarly journals The Neural Codes Underlying Internally Generated Representations in Visual Working Memory

2021 ◽  
pp. 1-16
Author(s):  
Qing Yu ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Subjective Experience ◽  
Neural Representation ◽  
Delayed Recall ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
Internal Sources ◽  
Scaling Analyses

Abstract Humans can construct rich subjective experience even when no information is available in the external world. Here, we investigated the neural representation of purely internally generated stimulus-like information during visual working memory. Participants performed delayed recall of oriented gratings embedded in noise with varying contrast during fMRI scanning. Their trialwise behavioral responses provided an estimate of their mental representation of the to-be-reported orientation. We used multivariate inverted encoding models to reconstruct the neural representations of orientation in reference to the response. We found that response orientation could be successfully reconstructed from activity in early visual cortex, even on 0% contrast trials when no orientation information was actually presented, suggesting the existence of a purely internally generated neural code in early visual cortex. In addition, cross-generalization and multidimensional scaling analyses demonstrated that information derived from internal sources was represented differently from typical working memory representations, which receive influences from both external and internal sources. Similar results were also observed in intraparietal sulcus, with slightly different cross-generalization patterns. These results suggest a potential mechanism for how externally driven and internally generated information is maintained in working memory.

scholarly journals Mental Imagery Follows Similar Cortical Reorganization as Perception: Intra-Modal and Cross-Modal Plasticity in Congenitally Blind

2018 ◽  
Vol 29 (7) ◽  
pp. 2859-2875 ◽  
Author(s):  
A W de Borst ◽  
B de Gelder
Keyword(s):  
Visual Cortex ◽  
Mental Imagery ◽  
Cortical Plasticity ◽  
Tactile Perception ◽  
Cortical Reorganization ◽  
Area V4 ◽  
Congenitally Blind ◽  
Early Visual Cortex ◽  
Blind Individuals ◽  
Discriminative Patterns

Abstract Cortical plasticity in congenitally blind individuals leads to cross-modal activation of the visual cortex and may lead to superior perceptual processing in the intact sensory domains. Although mental imagery is often defined as a quasi-perceptual experience, it is unknown whether it follows similar cortical reorganization as perception in blind individuals. In this study, we show that auditory versus tactile perception evokes similar intra-modal discriminative patterns in congenitally blind compared with sighted participants. These results indicate that cortical plasticity following visual deprivation does not influence broad intra-modal organization of auditory and tactile perception as measured by our task. Furthermore, not only the blind, but also the sighted participants showed cross-modal discriminative patterns for perception modality in the visual cortex. During mental imagery, both groups showed similar decoding accuracies for imagery modality in the intra-modal primary sensory cortices. However, no cross-modal discriminative information for imagery modality was found in early visual cortex of blind participants, in contrast to the sighted participants. We did find evidence of cross-modal activation of higher visual areas in blind participants, including the representation of specific-imagined auditory features in visual area V4.

scholarly journals Shared Representations for Working Memory and Mental Imagery in Early Visual Cortex

2013 ◽  
Vol 23 (15) ◽  
pp. 1427-1431 ◽  
Author(s):  
Anke Marit Albers ◽  
Peter Kok ◽  
Ivan Toni ◽  
H. Chris Dijkerman ◽  
Floris P. de Lange
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Mental Imagery ◽  
Shared Representations ◽  
Early Visual Cortex

The Depictive Nature of Visual Mental Imagery

1998 ◽  
pp. 221-227
Author(s):  
Norman Yujen Teng
Keyword(s):  
Content Analysis ◽  
Visual Cortex ◽  
Mental Imagery ◽  
Mental Representations ◽  
Image Representation ◽  
The Other ◽  
Mental Images ◽  
Visual Mental Imagery ◽  
Topographic Representation ◽  
The Brain

Tye argues that visual mental images have their contents encoded in topographically organized regions of the visual cortex, which support depictive representations; therefore, visual mental images rely at least in part on depictive representations. This argument, I contend, does not support its conclusion. I propose that we divide the problem about the depictive nature of mental imagery into two parts: one concerns the format of image representation and the other the conditions by virtue of which a representation becomes a depictive representation. Regarding the first part of the question, I argue that there exists a topographic format in the brain but that does not imply that there exists a depictive format of image representation. My answer to the second part of the question is that one needs a content analysis of a certain sort of topographic representations in order to make sense of depictive mental representations, and a topographic representation becomes a depictive representation by virtue of its content rather than its form.

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