scholarly journals Medial occipital cortex participates in a cortical network for transsaccadic feature discrimination: an fMRI paradigm

2021 ◽  
Author(s):  
B. R. Baltaretu ◽  
W. Dale Stevens ◽  
E. Freud ◽  
J. D. Crawford
Keyword(s):  
Spatial Frequency ◽  
Shape Change ◽  
Occipital Cortex ◽  
Cortical Network ◽  
Object Processing ◽  
Repetition Suppression ◽  
Early Visual Cortex ◽  
Transsaccadic Perception ◽  
Transsaccadic Memory ◽  
Object Features

AbstractTo date, the cortical correlates for human transsaccadic vision have been probed for single object features such as orientation (associated with parietal repetition suppression) and spatial frequency (associated with occipital repetition enhancement). Here, we used functional magnetic resonance imaging to distinguish cortical modulations associated with transsaccadic perception of multiple object features. Participants (n=21) viewed a 2D object and then, after sustained fixation or a saccade, judged whether the shape or orientation of the re-presented object had changed. Since feature change was randomized, participants had to remember both features across saccades to perform the task. A whole-brain voxelwise contrast (Saccade > Fixation; n=17) uncovered areas that might be specialized for transsaccadic memory, updating and/or perception, including medial occipital, dorsomedial posterior parietal, and dorsal frontal cortex. Searching within these regions, we then employed a feature contrast (Orientation vs. Shape change). This contrast revealed feature-specific modulations (consistent with shape change enhancement) in left medial occipital cortex. The peak site (left cuneus) showed contralateral functional connectivity with early visual cortex (lingual gyrus), object-processing areas (occipitotemporal cortex) and saccade / motor areas in parietal cortex. These observations show that medial occipital cortex participates in a cortical network involved in transsaccadic feature perception. Together with the previous literature, this suggests separate mechanisms for transsaccadic perception of intrinsic object features (spatial frequency, shape) versus object location and orientation.

scholarly journals Task and Spatial Frequency Modulations of Object Processing: An EEG Study

PLoS ONE ◽  
2013 ◽  
Vol 8 (7) ◽  
pp. e70293 ◽  
Author(s):  
Matt Craddock ◽  
Jasna Martinovic ◽  
Matthias M. Müller
Keyword(s):  
Spatial Frequency ◽  
Object Processing ◽  
Frequency Modulations

scholarly journals Top-down modulation in the infant brain: Learning-induced expectations rapidly affect the sensory cortex at 6 months

2015 ◽  
Vol 112 (31) ◽  
pp. 9585-9590 ◽  
Author(s):  
Lauren L. Emberson ◽  
John E. Richards ◽  
Richard N. Aslin
Keyword(s):  
Near Infrared ◽  
Predictive Coding ◽  
Empirical Support ◽  
Occipital Cortex ◽  
Theoretical Work ◽  
Functional Near Infrared Spectroscopy ◽  
Extensive Experience ◽  
Neural Organization ◽  
Repetition Suppression ◽  
Rudimentary Form

Recent theoretical work emphasizes the role of expectation in neural processing, shifting the focus from feed-forward cortical hierarchies to models that include extensive feedback (e.g., predictive coding). Empirical support for expectation-related feedback is compelling but restricted to adult humans and nonhuman animals. Given the considerable differences in neural organization, connectivity, and efficiency between infant and adult brains, it is a crucial yet open question whether expectation-related feedback is an inherent property of the cortex (i.e., operational early in development) or whether expectation-related feedback develops with extensive experience and neural maturation. To determine whether infants’ expectations about future sensory input modulate their sensory cortices without the confounds of stimulus novelty or repetition suppression, we used a cross-modal (audiovisual) omission paradigm and used functional near-infrared spectroscopy (fNIRS) to record hemodynamic responses in the infant cortex. We show that the occipital cortex of 6-month-old infants exhibits the signature of expectation-based feedback. Crucially, we found that this region does not respond to auditory stimuli if they are not predictive of a visual event. Overall, these findings suggest that the young infant’s brain is already capable of some rudimentary form of expectation-based feedback.

On-Line Attentional Selection From Competing Stimuli in Opposite Visual Fields: Effects on Human Visual Cortex and Control Processes

2006 ◽  
Vol 96 (5) ◽  
pp. 2601-2612 ◽  
Author(s):  
Joy J. Geng ◽  
Evelyn Eger ◽  
Christian C. Ruff ◽  
Árni Kristjánsson ◽  
Pia Rotshtein ◽  
...  
Keyword(s):  
Visual Fields ◽  
Occipital Cortex ◽  
Attentional Selection ◽  
Functional Coupling ◽  
Repetition Suppression ◽  
On Line ◽  
Orthogonal Orientation ◽  
And Control ◽  
Visual Hemifields ◽  
Anticipatory Attention

We used fMRI to investigate competition and on-line attentional selection between targets and distractors in opposite visual hemifields. Displays comprised a high-contrast square-wave grating, defined as target by its orientation, presented alone (unilateral) or with a similar distractor of orthogonal orientation in the opposite hemifield (bilateral displays). The target appeared unpredictably on the left or right, precluding anticipatory attention to one side. We found greater activation in target-contralateral superior occipital gyrus for unilateral than for bilateral displays, indicating suppression of the target’s visual representation by distractor presence despite the competing distractor projecting to a different occipital hemisphere. Several frontal and parietal regions showed greater activation for bilateral than unilateral trials, suggesting involvement in on-line attentional selection. This was particularly pronounced for regions in bilateral intraparietal sulcus (IPS), which also showed greater functional coupling with occipital cortex specifically on bilateral trials that required selection plus some repetition-suppression effects when target side was repeated, but again only on bilateral trials requiring selection. Our results indicate that competition between visual stimuli in opposite hemifields can influence occipital cortex, and implicate IPS in resolution of this competition by selection.

scholarly journals Parietal Mechanisms for Transsaccadic Spatial Frequency Perception: An fMRI Study

2020 ◽  
Author(s):  
B. R. Baltaretu ◽  
B. T. Dunkley ◽  
W. Dale Stevens ◽  
J. D. Crawford
Keyword(s):  
Spatial Frequency ◽  
Posterior Parietal Cortex ◽  
Right Hemisphere ◽  
Interaction Analysis ◽  
Posterior Cingulate Cortex ◽  
Precentral Gyrus ◽  
General Role ◽  
Psychophysiological Interaction ◽  
The Right ◽  
Transsaccadic Memory

AbstractPosterior parietal cortex (PPC), specifically right supramarginal gyrus, is involved in transsaccadic memory of object orientation for both perception and action. Here, we investigated whether PPC is involved in transsaccadic memory of other features, namely spatial frequency. We employed a functional magnetic resonance imaging paradigm where participants briefly viewed a grating stimulus with a specific spatial frequency that later reappeared with the same or different frequency, after a saccade or continuous fixation. Post-saccadic frequency modulation activated a region in the right hemisphere spanning medial PPC (ventral precuneus) and posterior cingulate cortex. Importantly, the site of peak precuneus activation showed saccade-specific feature modulation (compared to fixation) and task-specific saccade modulation (compared to a saccade localizer task). Psychophysiological interaction analysis revealed functional connectivity between this precuneus site and the precentral gyrus (M1), lingual gyrus (V1/V2), and medial occipitotemporal sulcus. This differed from the transsaccadic orientation network, perhaps because spatial frequency signaled changes in object identity. Overall, this experiment supports a general role for PPC in transsaccadic vision, but suggests that different networks are employed for specific features.

scholarly journals Integrative and distinctive coding of perceptual and conceptual object features in the ventral visual stream

2017 ◽  
Author(s):  
Chris B Martin ◽  
Danielle Douglas ◽  
Rachel N Newsome ◽  
Louisa LY Man ◽  
Morgan D Barense
Keyword(s):  
Cognitive Neuroscience ◽  
Occipital Cortex ◽  
Perirhinal Cortex ◽  
Visual Features ◽  
Visual Stream ◽  
Parahippocampal Cortex ◽  
Temporal Pole ◽  
Ventral Visual Stream ◽  
Object Features ◽  
Lateral Occipital Cortex

AbstractA tremendous body of research in cognitive neuroscience is aimed at understanding how object concepts are represented in the human brain. However, it remains unknown whether and where the visual and abstract conceptual features that define an object concept are integrated. We addressed this issue by comparing the neural pattern similarities among object-evoked fMRI responses with behavior-based models that independently captured the visual and conceptual similarities among these stimuli. Our results revealed evidence for distinctive coding of visual features in lateral occipital cortex, and conceptual features in the temporal pole and parahippocampal cortex. By contrast, we found evidence for integrative coding of visual and conceptual object features in perirhinal cortex. The neuroanatomical specificity of this effect was highlighted by results from a searchlight analysis. Taken together, our findings suggest that perirhinal cortex uniquely supports the representation of fully-specified object concepts through the integration of their visual and conceptual features.

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

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.

scholarly journals Population spatial frequency tuning in human early visual cortex

2020 ◽  
Vol 123 (2) ◽  
pp. 773-785 ◽  
Author(s):  
Sara Aghajari ◽  
Louis N. Vinke ◽  
Sam Ling
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Frequency Tuning ◽  
Efficient Estimation ◽  
Logarithmic Scale ◽  
Frequency Sensitivity ◽  
Spatial Frequency Tuning ◽  
Visual Areas ◽  
Early Visual Cortex ◽  
Band Pass

Neurons within early visual cortex are selective for basic image statistics, including spatial frequency. However, these neurons are thought to act as band-pass filters, with the window of spatial frequency sensitivity varying across the visual field and across visual areas. Although a handful of previous functional (f)MRI studies have examined human spatial frequency sensitivity using conventional designs and analysis methods, these measurements are time consuming and fail to capture the precision of spatial frequency tuning (bandwidth). In this study, we introduce a model-driven approach to fMRI analyses that allows for fast and efficient estimation of population spatial frequency tuning (pSFT) for individual voxels. Blood oxygen level-dependent (BOLD) responses within early visual cortex were acquired while subjects viewed a series of full-field stimuli that swept through a large range of spatial frequency content. Each stimulus was generated by band-pass filtering white noise with a central frequency that changed periodically between a minimum of 0.5 cycles/degree (cpd) and a maximum of 12 cpd. To estimate the underlying frequency tuning of each voxel, we assumed a log-Gaussian pSFT and optimized the parameters of this function by comparing our model output against the measured BOLD time series. Consistent with previous studies, our results show that an increase in eccentricity within each visual area is accompanied by a drop in the peak spatial frequency of the pSFT. Moreover, we found that pSFT bandwidth depends on eccentricity and is correlated with the pSFT peak; populations with lower peaks possess broader bandwidths in logarithmic scale, whereas in linear scale this relationship is reversed. NEW & NOTEWORTHY Spatial frequency selectivity is a hallmark property of early visuocortical neurons, and mapping these sensitivities gives us crucial insight into the hierarchical organization of information within visual areas. Due to technical obstacles, we lack a comprehensive picture of the properties of this sensitivity in humans. Here, we introduce a new method, coined population spatial frequency tuning mapping, which circumvents the limitations of the conventional neuroimaging methods, yielding a fuller visuocortical map of spatial frequency sensitivity.

Neuronal response to texture- and contrast-defined boundaries in early visual cortex

2007 ◽  
Vol 24 (1) ◽  
pp. 65-77 ◽  
Author(s):  
YUNING SONG ◽  
CURTIS L. BAKER
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Cortical Neurons ◽  
Visual Cues ◽  
Neuronal Response ◽  
Luminance Contrast ◽  
Movement Direction ◽  
Natural Scenes ◽  
Neural Responses ◽  
Early Visual Cortex

Natural scenes contain a variety of visual cues that facilitate boundary perception (e.g., luminance, contrast, and texture). Here we explore whether single neurons in early visual cortex can process both contrast and texture cues. We recorded neural responses in cat A18 to both illusory contours formed by abutting gratings (ICs, texture-defined) and contrast-modulated gratings (CMs, contrast-defined). We found that if a neuron responded to one of the two stimuli, it also responded to the other. These neurons signaled similar contour orientation, spatial frequency, and movement direction of the two stimuli. A given neuron also exhibited similar selectivity for spatial frequency of the fine, stationary grating components (carriers) of the stimuli. These results suggest that the cue-invariance of early cortical neurons extends to different kinds of texture or contrast cues, and might arise from a common nonlinear mechanism.

scholarly journals Transcranial Magnetic Stimulation to the Transverse Occipital Sulcus Affects Scene but Not Object Processing

2013 ◽  
Vol 25 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Rachel E. Ganaden ◽  
Caitlin R. Mullin ◽  
Jennifer K. E. Steeves
Keyword(s):  
Scene Perception ◽  
Occipital Cortex ◽  
Control Site ◽  
Image Features ◽  
Retrosplenial Cortex ◽  
Scene Recognition ◽  
Scene Categorization ◽  
Object Processing ◽  
Inhibitory Mechanisms ◽  
Scene Processing

Traditionally, it has been theorized that the human visual system identifies and classifies scenes in an object-centered approach, such that scene recognition can only occur once key objects within a scene are identified. Recent research points toward an alternative approach, suggesting that the global image features of a scene are sufficient for the recognition and categorization of a scene. We have previously shown that disrupting object processing with repetitive TMS to object-selective cortex enhances scene processing possibly through a release of inhibitory mechanisms between object and scene pathways [Mullin, C. R., & Steeves, J. K. E. TMS to the lateral occipital cortex disrupts object processing but facilitates scene processing. Journal of Cognitive Neuroscience, 23, 4174–4184, 2011]. Here we show the effects of TMS to the transverse occipital sulcus (TOS), an area implicated in scene perception, on scene and object processing. TMS was delivered to the TOS or the vertex (control site) while participants performed an object and scene natural/nonnatural categorization task. Transiently interrupting the TOS resulted in significantly lower accuracies for scene categorization compared with control conditions. This demonstrates a causal role of the TOS in scene processing and indicates its importance, in addition to the parahippocampal place area and retrosplenial cortex, in the scene processing network. Unlike TMS to object-selective cortex, which facilitates scene categorization, disrupting scene processing through stimulation of the TOS did not affect object categorization. Further analysis revealed a higher proportion of errors for nonnatural scenes that led us to speculate that the TOS may be involved in processing the higher spatial frequency content of a scene. This supports a nonhierarchical model of scene recognition.

scholarly journals TMS to the Lateral Occipital Cortex Disrupts Object Processing but Facilitates Scene Processing

2011 ◽  
Vol 23 (12) ◽  
pp. 4174-4184 ◽  
Author(s):  
Caitlin R. Mullin ◽  
Jennifer K. E. Steeves
Keyword(s):  
Temporal Dynamics ◽  
Scene Perception ◽  
Visual Image ◽  
Object Perception ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Object Processing ◽  
Repetitive Tms ◽  
Scene Processing ◽  
Lateral Occipital Cortex

The study of brain-damaged patients and advancements in neuroimaging have lead to the discovery of discrete brain regions that process visual image categories, such as objects and scenes. However, how these visual image categories interact remains unclear. For example, is scene perception simply an extension of object perception, or can global scene “gist” be processed independently of its component objects? Specifically, when recognizing a scene such as an “office,” does one need to first recognize its individual objects, such as the desk, chair, lamp, pens, and paper to build up the representation of an “office” scene? Here, we show that temporary interruption of object processing through repetitive TMS to the left lateral occipital cortex (LO), an area known to selectively process objects, impairs object categorization but surprisingly facilitates scene categorization. This result was replicated in a second experiment, which assessed the temporal dynamics of this disruption and facilitation. We further showed that repetitive TMS to left LO significantly disrupted object processing but facilitated scene processing when stimulation was administered during the first 180 msec of the task. This demonstrates that the visual system retains the ability to process scenes during disruption to object processing. Moreover, the facilitation of scene processing indicates disinhibition of areas involved in global scene processing, likely caused by disrupting inhibitory contributions from the LO. These findings indicate separate but interactive pathways for object and scene processing and further reveal a network of inhibitory connections between these visual brain regions.

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