Altered effective connectivity between lateral occipital cortex and superior parietal lobule contributes to manipulability-related modulation of the Ebbinghaus illusion

Cortex ◽  
2021 ◽  
Author(s):  
Lihong Chen ◽  
Shengnan Zhu ◽  
Bengang Feng ◽  
Xue Zhang ◽  
Yi Jiang
Keyword(s):  
Effective Connectivity ◽  
Occipital Cortex ◽  
Superior Parietal Lobule ◽  
Ebbinghaus Illusion ◽  
Parietal Lobule ◽  
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 The role of the superior parietal lobule in lexical processing of sign language: Insights from fMRI and TMS

Cortex ◽  
2021 ◽  
Vol 135 ◽  
pp. 240-254
Author(s):  
A. Banaszkiewicz ◽  
Ł. Bola ◽  
J. Matuszewski ◽  
M. Szczepanik ◽  
B. Kossowski ◽  
...  
Keyword(s):  
Sign Language ◽  
Lexical Processing ◽  
Superior Parietal Lobule ◽  
Parietal Lobule

Mental maze solving: directional fMRI tuning and population coding in the superior parietal lobule

2005 ◽  
Vol 165 (3) ◽  
pp. 273-282 ◽  
Author(s):  
Pavlos Gourtzelidis ◽  
Charidimos Tzagarakis ◽  
Scott M. Lewis ◽  
David A. Crowe ◽  
Edward Auerbach ◽  
...  
Keyword(s):  
Population Coding ◽  
Superior Parietal Lobule ◽  
Parietal Lobule

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 Ultra-high field parallel imaging of the superior parietal lobule during mental maze solving

2008 ◽  
Vol 187 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Trenton A. Jerde ◽  
Scott M. Lewis ◽  
Ute Goerke ◽  
Pavlos Gourtzelidis ◽  
Charidimos Tzagarakis ◽  
...  
Keyword(s):  
High Field ◽  
Parallel Imaging ◽  
Superior Parietal Lobule ◽  
Ultra High Field ◽  
Field Parallel ◽  
Parietal Lobule
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