Hallucinated and correctly detected stimuli evoke similar activity patterns in early visual cortex

Theories of visual selective attention propose that top–down preparatory attention signals mediate the selection of task-relevant information in cluttered scenes. Neuroimaging and electrophysiology studies have provided correlative evidence for this hypothesis, finding increased activity in target-selective neural populations in visual cortex in the period between a search cue and target onset. In this study, we used online TMS to test whether preparatory neural activity in visual cortex is causally involved in naturalistic object detection. In two experiments, participants detected the presence of object categories (cars, people) in a diverse set of photographs of real-world scenes. TMS was applied over a region in posterior temporal cortex identified by fMRI as carrying category-specific preparatory activity patterns. Results showed that TMS applied over posterior temporal cortex before scene onset (−200 and −100 msec) impaired the detection of object categories in subsequently presented scenes, relative to vertex and early visual cortex stimulation. This effect was specific to category level detection and was related to the type of attentional template participants adopted, with the strongest effects observed in participants adopting category level templates. These results provide evidence for a causal role of preparatory attention in mediating the detection of objects in cluttered daily-life environments.

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A self-supervised deep neural network for image completion resembles early visual cortex fMRI activity patterns for occluded scenes

Journal of Vision ◽

10.1167/jov.21.7.5 ◽

2021 ◽

Vol 21 (7) ◽

pp. 5

Author(s):

Michele Svanera ◽

Andrew T. Morgan ◽

Lucy S. Petro ◽

Lars Muckli

Keyword(s):

Neural Network ◽

Visual Cortex ◽

Deep Neural Network ◽

Activity Patterns ◽

Image Completion ◽

Early Visual Cortex

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Selective Modulation of Early Visual Cortical Activity by Movement Intention

Cerebral Cortex ◽

10.1093/cercor/bhy345 ◽

2019 ◽

Vol 29 (11) ◽

pp. 4662-4678 ◽

Cited By ~ 6

Author(s):

Jason P Gallivan ◽

Craig S Chapman ◽

Daniel J Gale ◽

J Randall Flanagan ◽

Jody C Culham

Keyword(s):

Visual Cortex ◽

Activity Patterns ◽

Action Planning ◽

Cortical Activity ◽

Target Object ◽

Movement Planning ◽

Dependent Manner ◽

Related Information ◽

Early Visual Cortex ◽

Visual Cortical

Abstract The primate visual system contains myriad feedback projections from higher- to lower-order cortical areas, an architecture that has been implicated in the top-down modulation of early visual areas during working memory and attention. Here we tested the hypothesis that these feedback projections also modulate early visual cortical activity during the planning of visually guided actions. We show, across three separate human functional magnetic resonance imaging (fMRI) studies involving object-directed movements, that information related to the motor effector to be used (i.e., limb, eye) and action goal to be performed (i.e., grasp, reach) can be selectively decoded—prior to movement—from the retinotopic representation of the target object(s) in early visual cortex. We also find that during the planning of sequential actions involving objects in two different spatial locations, that motor-related information can be decoded from both locations in retinotopic cortex. Together, these findings indicate that movement planning selectively modulates early visual cortical activity patterns in an effector-specific, target-centric, and task-dependent manner. These findings offer a neural account of how motor-relevant target features are enhanced during action planning and suggest a possible role for early visual cortex in instituting a sensorimotor estimate of the visual consequences of movement.

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Prior Expectations Evoke Stimulus Templates in the Primary Visual Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00562 ◽

2014 ◽

Vol 26 (7) ◽

pp. 1546-1554 ◽

Cited By ~ 104

Author(s):

Peter Kok ◽

Michel F. Failing ◽

Floris P. de Lange

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Activity Patterns ◽

Representational Content ◽

Specific Pattern ◽

Specific Stimulus ◽

Prior Expectation ◽

Early Visual Cortex ◽

Actual Stimulus ◽

Increased Activity

Sensory processing is strongly influenced by prior expectations. Valid expectations have been shown to lead to improvements in perception as well as in the quality of sensory representations in primary visual cortex. However, very little is known about the neural correlates of the expectations themselves. Previous studies have demonstrated increased activity in sensory cortex following the omission of an expected stimulus, yet it is unclear whether this increased activity constitutes a general surprise signal or rather has representational content. One intriguing possibility is that top–down expectation leads to the formation of a template of the expected stimulus in visual cortex, which can then be compared with subsequent bottom–up input. To test this hypothesis, we used fMRI to noninvasively measure neural activity patterns in early visual cortex of human participants during expected but omitted visual stimuli. Our results show that prior expectation of a specific visual stimulus evokes a feature-specific pattern of activity in the primary visual cortex (V1) similar to that evoked by the corresponding actual stimulus. These results are in line with the notion that prior expectation triggers the formation of specific stimulus templates to efficiently process expected sensory inputs.

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fMRI Activity Patterns in Human LOC Carry Information about Object Exemplars within Category

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2008.20019 ◽

2008 ◽

Vol 20 (2) ◽

pp. 356-370 ◽

Cited By ~ 117

Author(s):

Evelyn Eger ◽

John Ashburner ◽

John-Dylan Haynes ◽

Raymond J. Dolan ◽

Geraint Rees

Keyword(s):

Pattern Recognition ◽

Visual Cortex ◽

Activity Patterns ◽

Temporal Cortex ◽

Support Vector ◽

Specific Information ◽

Object Identity ◽

Stimulus Similarity ◽

Lateral Occipital Complex ◽

Early Visual Cortex

The lateral occipital complex (LOC) is a set of areas in the human occipito-temporal cortex responding to objects as opposed to low-level control stimuli. Conventional functional magnetic resonance imaging (fMRI) analysis methods based on regional averages could not detect signals discriminative of different types of objects in this region. Here, we examined fMRI signals using multivariate pattern recognition (support vector classification) to systematically explore the nature of object-related information available in fine-grained activity patterns in the LOC. Distributed fMRI signals from the LOC allowed for above-chance discrimination not only of the category but also of within-category exemplars of everyday man-made objects, and such exemplar-specific information generalized across changes in stimulus size and viewpoint, particularly in posterior subregions. Object identity could also be predicted from responses of the early visual cortex, even significantly across the changes in size and viewpoint used here. However, a dissociation was observed between these two regions of interest in the degree of discrimination for objects relative to size: In the early visual cortex, two different sizes of the same object were even better discriminated than two different objects (in accordance with measures of pixelwise stimulus similarity), whereas the opposite was true in the LOC. These findings provide the first evidence that direct evoked fMRI activity patterns in the LOC can be different for individual object exemplars (within a single category). We propose that pattern recognition methods as used here may provide an alternative approach to study mechanisms of neuronal representation based on aspects of the fMRI response independent of those assessed in adaptation paradigms.

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Contextual expectations shape cortical reinstatement of sensory representations

10.1101/2021.08.05.455275 ◽

2021 ◽

Author(s):

Alex Clarke ◽

Jordan E Crivelli-Decker ◽

Charan Ranganath

Keyword(s):

Visual Cortex ◽

Activity Patterns ◽

Medial Cortex ◽

Pattern Similarity ◽

Early Visual Cortex ◽

Animal Images ◽

Human Participants ◽

Visual Cortical ◽

Multivariate Pattern ◽

Perceptual Systems

When making a turn at a familiar intersection, we know what items and landmarks will come into view. These perceptual expectations, or predictions, come from our knowledge of the context, however it is unclear how memory and perceptual systems interact to support the prediction and reactivation of sensory details in cortex. To address this, human participants learned the spatial layout of animals positioned in a cross maze. During fMRI, participants navigated between animals to reach a target, and in the process saw a predictable sequence of five animal images. Critically, to isolate activity patterns related to item predictions, rather than bottom-up inputs, one quarter of trials ended early, with a blank screen presented instead. Using multivariate pattern similarity analysis, we reveal that activity patterns in early visual cortex, posterior medial regions, and the posterior hippocampus showed greater similarity when seeing the same item compared to different items. Further, item effects in posterior hippocampus were specific to the sequence context. Critically, activity patterns associated with seeing an item in visual cortex and posterior medial cortex, were also related to activity patterns when an item was expected, but omitted, suggesting sequence predictions were reinstated in these regions. Finally, multivariate connectivity showed that patterns in the posterior hippocampus at one position in the sequence were related to patterns in early visual cortex and posterior medial cortex at a later position. Together, our results support the idea that hippocampal representations facilitate sensory processing by modulating visual cortical activity in anticipation of expected items.

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Basic Level Category Structure Emerges Gradually across Human Ventral Visual Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00790 ◽

2015 ◽

Vol 27 (7) ◽

pp. 1427-1446 ◽

Cited By ~ 20

Author(s):

Marius Cătălin Iordan ◽

Michelle R. Greene ◽

Diane M. Beck ◽

Li Fei-Fei

Keyword(s):

Visual Cortex ◽

Activity Patterns ◽

Object Categories ◽

Visual Hierarchy ◽

Subordinate Level ◽

Early Visual Cortex ◽

Occipitotemporal Cortex ◽

Feature Overlap ◽

The Brain ◽

Basic Level

Objects can be simultaneously categorized at multiple levels of specificity ranging from very broad (“natural object”) to very distinct (“Mr. Woof”), with a mid-level of generality (basic level: “dog”) often providing the most cognitively useful distinction between categories. It is unknown, however, how this hierarchical representation is achieved in the brain. Using multivoxel pattern analyses, we examined how well each taxonomic level (superordinate, basic, and subordinate) of real-world object categories is represented across occipitotemporal cortex. We found that, although in early visual cortex objects are best represented at the subordinate level (an effect mostly driven by low-level feature overlap between objects in the same category), this advantage diminishes compared to the basic level as we move up the visual hierarchy, disappearing in object-selective regions of occipitotemporal cortex. This pattern stems from a combined increase in within-category similarity (category cohesion) and between-category dissimilarity (category distinctiveness) of neural activity patterns at the basic level, relative to both subordinate and superordinate levels, suggesting that successive visual areas may be optimizing basic level representations.

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