An Integrated Face–Body Representation in the Fusiform Gyrus but Not the Lateral Occipital Cortex

2014 ◽  
Vol 26 (11) ◽  
pp. 2469-2478 ◽  
Author(s):  
Michal Bernstein ◽  
Jonathan Oron ◽  
Boaz Sadeh ◽  
Galit Yovel
Keyword(s):  
Occipital Cortex ◽  
Body Representation ◽  
Simultaneous Presentation ◽  
Competitive Interactions ◽  
Competition Effect ◽  
Brain Areas ◽  
Object Processing ◽  
Distinct Category ◽  
Fmri Response ◽  
Lateral Occipital Cortex

Faces and bodies are processed by distinct category-selective brain areas. Neuroimaging studies have so far presented isolated faces and headless bodies, and therefore little is known on whether and where faces and headless bodies are grouped together to one object, as they appear in the real world. The current study examined whether a face presented above a body are represented as two separate images or as an integrated face–body representation in face and body-selective brain areas by employing a fMRI competition paradigm. This paradigm has been shown to reveal higher fMRI response to sequential than simultaneous presentation of multiple stimuli (i.e., the competition effect), indicating competitive interactions among simultaneously presented multiple stimuli. We therefore hypothesized that if a face above a body is integrated to an image of a person whereas a body above a face is represented as two separate objects, the competition effect will be larger for the latter than the former. Consistent with our hypothesis, our findings reveal a competition effect when a body is presented above a face, but not when a face is presented above a body, suggesting that a body above a face is represented as two separate objects whereas a face above a body is represented as an integrated image of a person. Interestingly, this integration of a face and a body to an image of a person was found in the fusiform, but not the lateral-occipital face and body areas. We conclude that faces and bodies are processed separately at early stages and are integrated to a unified image of a person at mid-level stages of object processing.

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.

scholarly journals Hippocampal Engagement during Recall Depends on Memory Content

2016 ◽  
Author(s):  
David A. Ross ◽  
Patrick Sadil ◽  
D. Merika Wilson ◽  
Rosemary A. Cowell
Keyword(s):  
Cognitive Processes ◽  
Effective Connectivity ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Object Processing ◽  
Parahippocampal Cortex ◽  
Image Patches ◽  
Memory Content ◽  
Associative Recall ◽  
Lateral Occipital Cortex

SummaryThe hippocampus is considered pivotal to recall, allowing retrieval of information not available in the immediate environment. In contrast, neocortex is thought to signal familiarity, and to contribute to recall only when called upon by the hippocampus. However, this view is not compatible with representational accounts of memory, which reject the mapping of cognitive processes onto brain regions. According to representational accounts, the hippocampus is not engaged by recall per se, rather it is engaged whenever hippocampal representations are required. To test whether hippocampus is engaged by recall when hippocampal representations are not required, we used functional imaging and a non-associative recall task, with images (objects, scenes) studied in isolation, and image-patches used as cues. As predicted by a representational account, hippocampal activation increased during recall of scenes – which are known to be processed by hippocampus – but not during recall of objects. Object recall instead engaged neocortical regions known to be involved in object-processing. Further supporting the representational account, effective connectivity analyses revealed that recall was associated with increased information flow out of lateral occipital cortex (object recall) and parahippocampal cortex (scene recall), suggesting that recall-related activation spread from neocortex to hippocampus, not the reverse.

scholarly journals The Neural Bases of Egocentric Spatial Representation for Extracorporeal and Corporeal Tasks: An fMRI Study

2021 ◽  
Vol 11 (8) ◽  
pp. 963
Author(s):  
Stephanie Leplaideur ◽  
Annelise Moulinet-Raillon ◽  
Quentin Duché ◽  
Lucie Chochina ◽  
Karim Jamal ◽  
...  
Keyword(s):  
Reference Frames ◽  
Occipital Cortex ◽  
Body Representation ◽  
Hemispheric Dominance ◽  
Midsagittal Plane ◽  
Fmri Study ◽  
Neural Bases ◽  
Straight Ahead ◽  
Healthy Participants ◽  
Lateral Occipital Cortex

(1) Background: Humans use reference frames to elaborate the spatial representations needed for all space-oriented behaviors such as postural control, walking, or grasping. We investigated the neural bases of two egocentric tasks: the extracorporeal subjective straight-ahead task (SSA) and the corporeal subjective longitudinal body plane task (SLB) in healthy participants using functional magnetic resonance imaging (fMRI). This work was an ancillary part of a study involving stroke patients. (2) Methods: Seventeen healthy participants underwent a 3T fMRI examination. During the SSA, participants had to divide the extracorporeal space into two equal parts. During the SLB, they had to divide their body along the midsagittal plane. (3) Results: Both tasks elicited a parieto-occipital network encompassing the superior and inferior parietal lobules and lateral occipital cortex, with a right hemispheric dominance. Additionally, the SLB > SSA contrast revealed activations of the left angular and premotor cortices. These areas, involved in attention and motor imagery suggest a greater complexity of corporeal processes engaging body representation. (4) Conclusions: This was the first fMRI study to explore the SLB-related activity and its complementarity with the SSA. Our results pave the way for the exploration of spatial cognitive impairment in patients.

scholarly journals Properties of Object Processing in Lateral Occipital Cortex

2004 ◽  
Vol 4 (8) ◽  
pp. 91-91 ◽  
Author(s):  
C. W. Tyler ◽  
L. T. Likova ◽  
A. R. Wade
Keyword(s):  
Occipital Cortex ◽  
Object Processing ◽  
Lateral Occipital Cortex

Equal Degrees of Object Selectivity for Upper and Lower Visual Field Stimuli

2010 ◽  
Vol 104 (4) ◽  
pp. 2075-2081 ◽  
Author(s):  
Lars Strother ◽  
Adrian Aldcroft ◽  
Cheryl Lavell ◽  
Tutis Vilis
Keyword(s):  
Visual Field ◽  
Occipital Cortex ◽  
Recognition System ◽  
Blood Oxygen Level Dependent ◽  
Lower Visual Field ◽  
Blood Oxygen Level ◽  
Visual Areas ◽  
Bold Responses ◽  
Cortical Regions ◽  
Lateral Occipital Cortex

Functional MRI (fMRI) studies of the human object recognition system commonly identify object-selective cortical regions by comparing blood oxygen level–dependent (BOLD) responses to objects versus those to scrambled objects. Object selectivity distinguishes human lateral occipital cortex (LO) from earlier visual areas. Recent studies suggest that, in addition to being object selective, LO is retinotopically organized; LO represents both object and location information. Although LO responses to objects have been shown to depend on location, it is not known whether responses to scrambled objects vary similarly. This is important because it would suggest that the degree of object selectivity in LO does not vary with retinal stimulus position. We used a conventional functional localizer to identify human visual area LO by comparing BOLD responses to objects versus scrambled objects presented to either the upper (UVF) or lower (LVF) visual field. In agreement with recent findings, we found evidence of position-dependent responses to objects. However, we observed the same degree of position dependence for scrambled objects and thus object selectivity did not differ for UVF and LVF stimuli. We conclude that, in terms of BOLD response, LO discriminates objects from non-objects equally well in either visual field location, despite stronger responses to objects in the LVF.

scholarly journals Sensory perception in autism: an fMRI ALE meta-analysis

2020 ◽  
Author(s):  
Nazia Jassim ◽  
Simon Baron-Cohen ◽  
John Suckling
Keyword(s):  
Meta Analysis ◽  
Likelihood Estimation ◽  
Sensory Perception ◽  
Superior Temporal Gyrus ◽  
Occipital Cortex ◽  
Anterior Cingulate ◽  
Future Research ◽  
Precentral Gyrus ◽  
And Control ◽  
Lateral Occipital Cortex

Sensory sensitivities occur in up to 90% of autistic individuals. With the recent inclusion of sensory symptoms in the diagnostic criteria for autism, there is a current need to develop neural hypotheses related to autistic sensory perception. Using activation likelihood estimation (ALE), we meta-analysed 52 task-based fMRI studies investigating differences between autistic (n=891) and control (n=967) participants during non-social sensory perception. During complex perception, autistic groups showed more activity in the secondary somatosensory and occipital cortices, insula, caudate, superior temporal gyrus, and inferior parietal lobule, while control groups showed more activity in the frontal and parietal regions. During basic sensory processing, autistic groups showed hyperactivity in the lateral occipital cortex, primary somatosensory and motor cortices, insula, caudate, and thalamus, while controls showed heightened activity in the precentral gyrus, middle frontal gyrus, precuneus, and anterior cingulate cortex. We conclude that autistic individuals, on average, show distinct engagement of sensory-related brain networks during sensory perception. These findings may help guide future research to focus on relevant neurobiological mechanisms underpinning the autistic experience.

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