Visual Size Processing in Early Visual Cortex Follows Lateral Occipital Cortex Involvement

Objects can be recognized based on their intrinsic features, including shape, color, and texture. In daily life, however, such features are often not clearly visible, for example when objects appear in the periphery, in clutter, or at a distance. Interestingly, object recognition can still be highly accurate under these conditions when objects are seen within their typical scene context. What are the neural mechanisms of context-based object recognition? According to parallel processing accounts, context-based object recognition is supported by the parallel processing of object and scene information in separate pathways. Output of these pathways is then combined in downstream regions, leading to contextual benefits in object recognition. Alternatively, according to feedback accounts, context-based object recognition is supported by feedback from scene-selective to object-selective regions. Here, in three pre-registered transcranial magnetic stimulation (TMS) experiments, we tested a key prediction of the feedback hypothesis: that scene-selective cortex causally and selectively supports context-based object recognition before object-selective cortex does. Early visual cortex (EVC), object-selective lateral occipital cortex (LOC), and scene-selective occipital place area (OPA) were stimulated at three time points relative to stimulus onset while participants categorized degraded objects in scenes and intact objects in isolation, in different trials. Results confirmed our predictions: relative to isolated object recognition, context-based object recognition was selectively and causally supported by OPA at 160-200 ms after onset, followed by LOC at 260-300 ms after onset. These results indicate that context-based expectations facilitate object recognition by disambiguating object representations in visual cortex.

Causal neural mechanisms of context-based object recognition

eLife ◽

10.7554/elife.69736 ◽

2021 ◽

Vol 10 ◽

Author(s):

Miles Wischnewski ◽

Marius V Peelen

Keyword(s):

Visual Cortex ◽

Object Recognition ◽

Parallel Processing ◽

Occipital Cortex ◽

Stimulus Onset ◽

Neural Mechanisms ◽

Object Representations ◽

Early Visual Cortex ◽

Indirect Feedback ◽

Lateral Occipital Cortex

Objects can be recognized based on their intrinsic features, including shape, color, and texture. In daily life, however, such features are often not clearly visible, for example when objects appear in the periphery, in clutter, or at a distance. Interestingly, object recognition can still be highly accurate under these conditions when objects are seen within their typical scene context. What are the neural mechanisms of context-based object recognition? According to parallel processing accounts, context-based object recognition is supported by the parallel processing of object and scene information in separate pathways. Output of these pathways is then combined in downstream regions, leading to contextual benefits in object recognition. Alternatively, according to feedback accounts, context-based object recognition is supported by (direct or indirect) feedback from scene-selective to object-selective regions. Here, in three pre-registered transcranial magnetic stimulation (TMS) experiments, we tested a key prediction of the feedback hypothesis: that scene-selective cortex causally and selectively supports context-based object recognition before object-selective cortex does. Early visual cortex (EVC), object-selective lateral occipital cortex (LOC), and scene-selective occipital place area (OPA) were stimulated at three time points relative to stimulus onset while participants categorized degraded objects in scenes and intact objects in isolation, in different trials. Results confirmed our predictions: relative to isolated object recognition, context-based object recognition was selectively and causally supported by OPA at 160–200 ms after onset, followed by LOC at 260–300 ms after onset. These results indicate that context-based expectations facilitate object recognition by disambiguating object representations in the visual cortex.

Minimal Recognizable Configurations Elicit Category-selective Responses in Higher Order Visual Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01420 ◽

2019 ◽

Vol 31 (9) ◽

pp. 1354-1367

Author(s):

Yael Holzinger ◽

Shimon Ullman ◽

Daniel Harari ◽

Marlene Behrmann ◽

Galia Avidan

Keyword(s):

Visual Cortex ◽

Object Recognition ◽

Visual Recognition ◽

Recognition Performance ◽

Occipital Cortex ◽

Building Blocks ◽

Visual Object ◽

Visual Object Recognition ◽

Face Area ◽

Early Visual Cortex

Visual object recognition is performed effortlessly by humans notwithstanding the fact that it requires a series of complex computations, which are, as yet, not well understood. Here, we tested a novel account of the representations used for visual recognition and their neural correlates using fMRI. The rationale is based on previous research showing that a set of representations, termed “minimal recognizable configurations” (MIRCs), which are computationally derived and have unique psychophysical characteristics, serve as the building blocks of object recognition. We contrasted the BOLD responses elicited by MIRC images, derived from different categories (faces, objects, and places), sub-MIRCs, which are visually similar to MIRCs, but, instead, result in poor recognition and scrambled, unrecognizable images. Stimuli were presented in blocks, and participants indicated yes/no recognition for each image. We confirmed that MIRCs elicited higher recognition performance compared to sub-MIRCs for all three categories. Whereas fMRI activation in early visual cortex for both MIRCs and sub-MIRCs of each category did not differ from that elicited by scrambled images, high-level visual regions exhibited overall greater activation for MIRCs compared to sub-MIRCs or scrambled images. Moreover, MIRCs and sub-MIRCs from each category elicited enhanced activation in corresponding category-selective regions including fusiform face area and occipital face area (faces), lateral occipital cortex (objects), and parahippocampal place area and transverse occipital sulcus (places). These findings reveal the psychological and neural relevance of MIRCs and enable us to make progress in developing a more complete account of object recognition.

Typical visual-field locations enhance processing in object-selective channels of human occipital cortex

Journal of Neurophysiology ◽

10.1152/jn.00229.2018 ◽

2018 ◽

Vol 120 (2) ◽

pp. 848-853 ◽

Cited By ~ 14

Author(s):

Daniel Kaiser ◽

Radoslaw M. Cichy

Keyword(s):

Visual Cortex ◽

Visual Field ◽

Functional Mri ◽

Object Perception ◽

Occipital Cortex ◽

Natural Environments ◽

Lower Visual Field ◽

Cortical Processing ◽

Upper Visual Field ◽

Early Visual Cortex

Natural environments consist of multiple objects, many of which repeatedly occupy similar locations within a scene. For example, hats are seen on people’s heads, while shoes are most often seen close to the ground. Such positional regularities bias the distribution of objects across the visual field: hats are more often encountered in the upper visual field, while shoes are more often encountered in the lower visual field. Here we tested the hypothesis that typical visual field locations of objects facilitate cortical processing. We recorded functional MRI while participants viewed images of objects that were associated with upper or lower visual field locations. Using multivariate classification, we show that object information can be more successfully decoded from response patterns in object-selective lateral occipital cortex (LO) when the objects are presented in their typical location (e.g., shoe in the lower visual field) than when they are presented in an atypical location (e.g., shoe in the upper visual field). In a functional connectivity analysis, we relate this benefit to increased coupling between LO and early visual cortex, suggesting that typical object positioning facilitates information propagation across the visual hierarchy. Together these results suggest that object representations in occipital visual cortex are tuned to the structure of natural environments. This tuning may support object perception in spatially structured environments. NEW & NOTEWORTHY In the real world, objects appear in predictable spatial locations. Hats, commonly appearing on people’s heads, often fall into the upper visual field. Shoes, mostly appearing on people’s feet, often fall into the lower visual field. Here we used functional MRI to demonstrate that such regularities facilitate cortical processing: Objects encountered in their typical locations are coded more efficiently, which may allow us to effortlessly recognize objects in natural environments.

Anodal Occipital Transcranial Direct Current Stimulation Enhances Perceived Visual Size Illusions

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01664 ◽

2020 ◽

pp. 1-8

Author(s):

Anqi Wang ◽

Lihong Chen ◽

Yi Jiang

Keyword(s):

Visual Cortex ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Size Perception ◽

Central Target ◽

Direct Current Stimulation ◽

Visual Areas ◽

Early Visual Cortex ◽

Context Dependent ◽

Visual Size

Human early visual cortex has long been suggested to play a crucial role in context-dependent visual size perception through either lateral interaction or feedback projections from higher to lower visual areas. We investigated the causal contribution of early visual cortex to context-dependent visual size perception using the technique of transcranial direct current stimulation and two well-known size illusions (i.e., the Ebbinghaus and Ponzo illusions) and further elucidated the underlying mechanism that mediates the effect of transcranial direct current stimulation over early visual cortex. The results showed that the magnitudes of both size illusions were significantly increased by anodal stimulation relative to sham stimulation but left unaltered by cathodal stimulation. Moreover, the anodal effect persisted even when the central target and surrounding inducers of the Ebbinghaus configuration were presented to different eyes, with the effect lasting no more than 15 min. These findings provide compelling evidence that anodal occipital stimulation enhances the perceived visual size illusions, which is possibly mediated by weakening the suppressive function of the feedback connections from higher to lower visual areas. Moreover, the current study provides further support for the causal role of early visual cortex in the neural processing of context-dependent visual size perception.

Retinotopy with coordinates of lateral occipital cortex in humans

Journal of Neurosurgery ◽

10.3171/jns.2004.101.1.0114 ◽

2004 ◽

Vol 101 (1) ◽

pp. 114-118 ◽

Cited By ~ 13

Author(s):

Takanobu Kaido ◽

Tohru Hoshida ◽

Toshiaki Taoka ◽

Toshisuke Sakaki

Keyword(s):

Visual Cortex ◽

Visual Field ◽

Occipital Lobe ◽

Occipital Cortex ◽

Cortical Stimulation ◽

Content Type ◽

X Ray ◽

Lateral Occipital Cortex ◽

Fine Print ◽

Stimulation Of

Object. The lateral occipital cortex in humans is known as the “extrastriate visual cortex.” It is, however, an unexplored field of research, and the anatomical nomenclature for its surface has still not been standardized. This study was designed to investigate whether the lateral occipital cortex in humans has retinotopic representation. Methods. Four right-handed patients with a diagnosis of intractable epilepsy from space-occupying lesions in the occipital lobe or epilepsy originating in the occipital lobe received permanently implanted subdural electrodes. Electrical cortical stimulation was applied directly applied to the brain through metal electrodes by using a biphasic stimulator. The location of each electrode was measured on a lateral skull x-ray study. Each patient considered a whiteboard with vertical and horizontal median lines. The patient was asked to look at the midpoint on the whiteboard. If a visual hallucination or illusion occurred, the patient recorded its outline, shape, color, location, and motion on white paper one tenth the size of, and with vertical and horizontal median lines similar to those on, the whiteboard. Polar angles and eccentricities of the midpoints of the phosphenes from the coordinate origin were measured on the paper. On stimulation of the lateral occipital lobe, 44 phosphenes occurred. All phosphenes were circular or dotted, with a diameter of approximately 1 cm, except one that was like a curtain in the peripheral end of the upper and lower visual fields on stimulation of the parietooccipital region. All phosphenes appeared in the visual field contralateral to the cerebral hemisphere stimulated. On stimulation of the lateral occipital lobe, 22 phosphenes moved centrifugally or toward a horizontal line. From three-dimensional scatterplots and contour maps of the polar angles and eccentricities in relation to the x-ray coordinates of the electrodes, one can infer that the lateral occipital cortex in humans has retinotopic representation. Conclusions. The authors found that phosphenes induced by electrical cortical stimulation of the lateral occipital cortex represent retinotopy. From these results one can assert that visual field representation with retinotopic relation exists in the extrastriate visual cortex.

Intrinsic cortical dynamics dominate population responses to natural images across human visual cortex

10.1101/008961 ◽

2014 ◽

Cited By ~ 1

Author(s):

Linda Henriksson ◽

Seyed-Mahdi Khaligh-Razavi ◽

Kendrick Kay ◽

Nikolaus Kriegeskorte

Keyword(s):

Visual Cortex ◽

Occipital Cortex ◽

Brain Regions ◽

Gabor Wavelet ◽

Natural Image ◽

Response Patterns ◽

Cortical Dynamics ◽

Visual Areas ◽

Pyramid Model ◽

Lateral Occipital Cortex

Intrinsic cortical dynamics are thought to underlie trial-to-trial variability of visually evoked responses in animal models. Understanding their function in the context of sensory processing and representation is a major current challenge. Here we report that intrinsic cortical dynamics strongly affect the representational geometry of a brain region, as reflected in response-pattern dissimilarities, and exaggerate the similarity of representations between brain regions. We characterized the representations in several human visual areas by representational dissimilarity matrices (RDMs) constructed from fMRI response-patterns for natural image stimuli. The RDMs of different visual areas were highly similar when the response-patterns were estimated on the basis of the same trials (sharing intrinsic cortical dynamics), and quite distinct when patterns were estimated on the basis of separate trials (sharing only the stimulus-driven component). We show that the greater similarity of the representational geometries can be explained by the coherent fluctuations of regional-mean activation within visual cortex, reflecting intrinsic dynamics. Using separate trials to study stimulus-driven representations revealed clearer distinctions between the representational geometries: a Gabor wavelet pyramid model explained representational geometry in visual areas V1–3 and a categorical animate–inanimate model in the object-responsive lateral occipital cortex.

Assessing the Effect of Early Visual Cortex Transcranial Magnetic Stimulation on Working Memory Consolidation

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01113 ◽

2017 ◽

Vol 29 (7) ◽

pp. 1226-1238 ◽

Cited By ~ 7

Author(s):

Amanda E. van Lamsweerde ◽

Jeffrey S. Johnson

Keyword(s):

Working Memory ◽

Visual Cortex ◽

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Spatial Information ◽

Single Pulse ◽

Occipital Cortex ◽

Brain Regions ◽

Early Visual Cortex ◽

Stimulus Offset

Maintaining visual working memory (VWM) representations recruits a network of brain regions, including the frontal, posterior parietal, and occipital cortices; however, it is unclear to what extent the occipital cortex is engaged in VWM after sensory encoding is completed. Noninvasive brain stimulation data show that stimulation of this region can affect working memory (WM) during the early consolidation time period, but it remains unclear whether it does so by influencing the number of items that are stored or their precision. In this study, we investigated whether single-pulse transcranial magnetic stimulation (spTMS) to the occipital cortex during VWM consolidation affects the quantity or quality of VWM representations. In three experiments, we disrupted VWM consolidation with either a visual mask or spTMS to retinotopic early visual cortex. We found robust masking effects on the quantity of VWM representations up to 200 msec poststimulus offset and smaller, more variable effects on WM quality. Similarly, spTMS decreased the quantity of VWM representations, but only when it was applied immediately following stimulus offset. Like visual masks, spTMS also produced small and variable effects on WM precision. The disruptive effects of both masks and TMS were greatly reduced or entirely absent within 200 msec of stimulus offset. However, there was a reduction in swap rate across all time intervals, which may indicate a sustained role of the early visual cortex in maintaining spatial information.

No overlap between unconscious and imagined representations

10.31234/osf.io/ctdmk ◽

2021 ◽

Author(s):

Nadine Dijkstra

Keyword(s):

Visual Cortex ◽

Long Range ◽

Visual Representations ◽

Occipital Cortex ◽

Conscious Perception ◽

Neural Processing ◽

Feedback Processing ◽

Unconscious Processing ◽

Neural Representations ◽

Lateral Occipital Cortex

Visual representations can be generated via feedforward or feedback processes. The extent to which these processes result in overlapping representations remains unclear. Previous work has shown that imagined stimuli elicit similar representations as perceived stimuli throughout the visual cortex. However, while representations during imagery are indeed only caused by feedback processing, neural processing during perception is an interplay of both feedforward and feedback processing. This means that any overlap could be due to overlap in feedback processes. In the current study we aimed to investigate this issue by characterizing the overlap between feedforward- and feedback-initiated category-representations during imagery, conscious perception and unconscious processing using fMRI. While all three conditions elicited stimulus representations in left lateral occipital cortex (LOC), significant similarities were only observed between imagery and conscious perception in this area. Furthermore, PPI-analyses revealed stronger connectivity between frontal areas and left LOC during conscious perception and imagery compared to unconscious processing. Together, these findings can be explained by the idea that long-range feedback modifies visual representations, thereby reducing neural overlap between purely feedforward and feedback-initiated stimulus representations measured by fMRI. Neural representations caused by feedback, either stimulus-driven (perception) or internally-driven (imagery), are however relatively similar.

Phosphene perceptions and safety of chronic visual cortex stimulation in a blind subject

Journal of Neurosurgery ◽

10.3171/2019.3.jns182774 ◽

2020 ◽

Vol 132 (6) ◽

pp. 2000-2007 ◽

Cited By ~ 3

Author(s):

Soroush Niketeghad ◽

Abirami Muralidharan ◽

Uday Patel ◽

Jessy D. Dorn ◽

Laura Bonelli ◽

...

Keyword(s):

Visual Cortex ◽

Adverse Events ◽

Clinical Intervention ◽

Occipital Cortex ◽

Neuronal Population ◽

Serious Adverse Events ◽

Stimulation Parameters ◽

The Right ◽

Visual Cortical ◽

Stimulation Of

Stimulation of primary visual cortices has the potential to restore some degree of vision to blind individuals. Developing safe and reliable visual cortical prostheses requires assessment of the long-term stability, feasibility, and safety of generating stimulation-evoked perceptions.A NeuroPace responsive neurostimulation system was implanted in a blind individual with an 8-year history of bare light perception, and stimulation-evoked phosphenes were evaluated over 19 months (41 test sessions). Electrical stimulation was delivered via two four-contact subdural electrode strips implanted over the right medial occipital cortex. Current and charge thresholds for eliciting visual perception (phosphenes) were measured, as were the shape, size, location, and intensity of the phosphenes. Adverse events were also assessed.Stimulation of all contacts resulted in phosphene perception. Phosphenes appeared completely or partially in the left hemifield. Stimulation of the electrodes below the calcarine sulcus elicited phosphenes in the superior hemifield and vice versa. Changing the stimulation parameters of frequency, pulse width, and burst duration affected current thresholds for eliciting phosphenes, and increasing the amplitude or frequency of stimulation resulted in brighter perceptions. While stimulation thresholds decreased between an average of 5% and 12% after 19 months, spatial mapping of phosphenes remained consistent over time. Although no serious adverse events were observed, the subject experienced mild headaches and dizziness in three instances, symptoms that did not persist for more than a few hours and for which no clinical intervention was required.Using an off-the-shelf neurostimulator, the authors were able to reliably generate phosphenes in different areas of the visual field over 19 months with no serious adverse events, providing preliminary proof of feasibility and safety to proceed with visual epicortical prosthetic clinical trials. Moreover, they systematically explored the relationship between stimulation parameters and phosphene thresholds and discovered the direct relation of perception thresholds based on primary visual cortex (V1) neuronal population excitation thresholds.