scholarly journals The Lateral Occipital Cortex in the Face Perception Network: An Effective Connectivity Study

2012 ◽  
Vol 3 ◽  
Author(s):  
Krisztina Nagy ◽  
Mark W. Greenlee ◽  
Gyula Kovács
Keyword(s):  
Face Perception ◽  
Effective Connectivity ◽  
Occipital Cortex ◽  
The Face ◽  
Lateral Occipital Cortex

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.

Ventral and Dorsal Stream Interactions during the Perception of the Müller-Lyer Illusion: Evidence Derived from fMRI and Dynamic Causal Modeling

2012 ◽  
Vol 24 (10) ◽  
pp. 2015-2029 ◽  
Author(s):  
Thorsten Plewan ◽  
Ralph Weidner ◽  
Simon B. Eickhoff ◽  
Gereon R. Fink
Keyword(s):  
Parietal Cortex ◽  
Effective Connectivity ◽  
Dorsal Stream ◽  
Occipital Cortex ◽  
Causal Modeling ◽  
Dynamic Causal Modeling ◽  
Lyer Illusion ◽  
Superior Parietal Cortex ◽  
Transformation Processes ◽  
Lateral Occipital Cortex

The human visual system converts identically sized retinal stimuli into different-sized perceptions. For instance, the Müller-Lyer illusion alters the perceived length of a line via arrows attached to its end. The strength of this illusion can be expressed as the difference between physical and perceived line length. Accordingly, illusion strength reflects how strong a representation is transformed along its way from a retinal image up to a conscious percept. In this study, we investigated changes of effective connectivity between brain areas supporting these transformation processes to further elucidate the neural underpinnings of optical illusions. The strength of the Müller-Lyer illusion was parametrically modulated while participants performed either a spatial or a luminance task. Lateral occipital cortex and right superior parietal cortex were found to be associated with illusion strength. Dynamic causal modeling was employed to investigate putative interactions between ventral and dorsal visual streams. Bayesian model selection indicated that a model that involved bidirectional connections between dorsal and ventral stream areas most accurately accounted for the underlying network dynamics. Connections within this network were partially modulated by illusion strength. The data further suggest that the two areas subserve differential roles: Whereas lateral occipital cortex seems to be directly related to size transformation processes, activation in right superior parietal cortex may reflect subsequent levels of processing, including task-related supervisory functions. Furthermore, the data demonstrate that the observer's top–down settings modulate the interactions between lateral occipital and superior parietal regions and thereby influence the effect of illusion strength.

scholarly journals Dynamic Facial Expressions Evoke Distinct Activation in the Face Perception Network: A Connectivity Analysis Study

2012 ◽  
Vol 24 (2) ◽  
pp. 507-520 ◽  
Author(s):  
Elaine Foley ◽  
Gina Rippon ◽  
Ngoc Jade Thai ◽  
Olivia Longe ◽  
Carl Senior
Keyword(s):  
Facial Expressions ◽  
Face Perception ◽  
Effective Connectivity ◽  
Inferior Frontal Gyrus ◽  
Neural System ◽  
Connectivity Analysis ◽  
Facial Stimuli ◽  
Dynamic Facial Expressions ◽  
The Face ◽  
Cortical Regions

Very little is known about the neural structures involved in the perception of realistic dynamic facial expressions. In the present study, a unique set of naturalistic dynamic facial emotional expressions was created. Through fMRI and connectivity analysis, a dynamic face perception network was identified, which is demonstrated to extend Haxby et al.'s [Haxby, J. V., Hoffman, E. A., & Gobbini, M. I. The distributed human neural system for face perception. Trends in Cognitive Science, 4, 223–233, 2000] distributed neural system for face perception. This network includes early visual regions, such as the inferior occipital gyrus, which is identified as insensitive to motion or affect but sensitive to the visual stimulus, the STS, identified as specifically sensitive to motion, and the amygdala, recruited to process affect. Measures of effective connectivity between these regions revealed that dynamic facial stimuli were associated with specific increases in connectivity between early visual regions, such as the inferior occipital gyrus and the STS, along with coupling between the STS and the amygdala, as well as the inferior frontal gyrus. These findings support the presence of a distributed network of cortical regions that mediate the perception of different dynamic facial expressions.

scholarly journals Test-retest reliability of effective connectivity in the face perception network

2015 ◽  
Vol 37 (2) ◽  
pp. 730-744 ◽  
Author(s):  
Stefan Frässle ◽  
Frieder Michel Paulus ◽  
Sören Krach ◽  
Andreas Jansen
Keyword(s):  
Face Perception ◽  
Effective Connectivity ◽  
Retest Reliability ◽  
The Face ◽  
Test Retest Reliability

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 Confidence of emotion expression recognition recruits brain regions outside the face perception network

2018 ◽  
Vol 14 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Indrit Bègue ◽  
Maarten Vaessen ◽  
Jeremy Hofmeister ◽  
Marice Pereira ◽  
Sophie Schwartz ◽  
...  
Keyword(s):  
Face Perception ◽  
Brain Regions ◽  
Emotion Expression ◽  
Expression Recognition ◽  
The Face

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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