Time-Varying Effective Connectivity for Investigating the Neurophysiological Basis of Cognitive Processes

2014 ◽  
pp. 171-204 ◽  
Author(s):  
Jlenia Toppi ◽  
Manuela Petti ◽  
Donatella Mattia ◽  
Fabio Babiloni ◽  
Laura Astolfi
Keyword(s):  
Cognitive Processes ◽  
Effective Connectivity ◽  
Time Varying ◽  
Neurophysiological Basis

scholarly journals Time-Varying Effective Connectivity during Visual Object Naming as a Function of Semantic Demands

2015 ◽  
Vol 35 (23) ◽  
pp. 8768-8776 ◽  
Author(s):  
C. Poch ◽  
M. I. Garrido ◽  
J. M. Igoa ◽  
M. Belinchon ◽  
I. Garcia-Morales ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Visual Object ◽  
Object Naming ◽  
Time Varying ◽  
Visual Object Naming

Time-varying effective connectivity of the cortical neuroelectric activity associated with behavioural microsleeps

NeuroImage ◽  
2016 ◽  
Vol 124 ◽  
pp. 421-432 ◽  
Author(s):  
Jlenia Toppi ◽  
Laura Astolfi ◽  
Govinda R. Poudel ◽  
Carrie R.H. Innes ◽  
Fabio Babiloni ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Time Varying

scholarly journals Convergence of cortical types and functional motifs in the human mesiotemporal lobe

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Casey Paquola ◽  
Oualid Benkarim ◽  
Jordan DeKraker ◽  
Sara Larivière ◽  
Stefan Frässle ◽  
...  
Keyword(s):  
High Resolution ◽  
Cognitive Processes ◽  
Large Scale ◽  
Effective Connectivity ◽  
Brain Disorders ◽  
Neuronal Density ◽  
Functional Organisation ◽  
Large Scale Networks ◽  
Anterior Posterior

The mesiotemporal lobe (MTL) is implicated in many cognitive processes, is compromised in numerous brain disorders, and exhibits a gradual cytoarchitectural transition from six-layered parahippocampal isocortex to three-layered hippocampal allocortex. Leveraging an ultra-high-resolution histological reconstruction of a human brain, our study showed that the dominant axis of MTL cytoarchitectural differentiation follows the iso-to-allocortical transition and depth-specific variations in neuronal density. Projecting the histology-derived MTL model to in-vivo functional MRI, we furthermore determined how its cytoarchitecture underpins its intrinsic effective connectivity and association to large-scale networks. Here, the cytoarchitectural gradient was found to underpin intrinsic effective connectivity of the MTL, but patterns differed along the anterior-posterior axis. Moreover, while the iso-to-allocortical gradient parametrically represented the multiple-demand relative to task-negative networks, anterior-posterior gradients represented transmodal versus unimodal networks. Our findings establish that the combination of micro- and macrostructural features allow the MTL to represent dominant motifs of whole-brain functional organisation.

Event-Related Potentials and Cognitive Processing of Affectively Toned Words in Depression

2002 ◽  
Vol 16 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Marc Antony Serfaty ◽  
Robert Bothwell ◽  
Richard Marsh ◽  
Heather Ashton ◽  
Robert Blizard ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Cognitive Processes ◽  
Reaction Times ◽  
Event Related Potentials ◽  
Major Depressive ◽  
Depressed Patients ◽  
Electrophysiological Responses ◽  
Related Potentials ◽  
The Relationship ◽  
Neurophysiological Basis

Abstract Background: Depressed subjects and euthymic controls demonstrate differences in cognitive processing and brain electrophysiology. Contingent negative variation (CNV) and postimperative negative variation (PINV) was used to investigate the relationship between cognition and cortical event related potentials. Method: Electrophysiological responses and memory of different personality trait adjectives were measured in 15 patients with major depressive disorder and 15 euthymic controls. The words were presented acoustically to elicit event-related potentials. The subjects were asked to indicate whether the words were self-referential. Responses were measured separately for self referential and non-self referential, neutral, positively and negatively toned words. Results: Depressed patients chose more negative and fewer positive words as self-referential, though no significant differences between groups in CNV magnitude for any of the words were found. Persistence of cortical negativity after the motor response (PINV) was significantly (P < 0.02) greater in patients for all non-self-referential words, and reaction times were significantly longer for all words. Recall of positive words and recognition of all words were significantly impaired in patients. Conclusions: Both electrophysiological measures and memory tests found differences between depressed patients and controls, suggesting that the PINV wave may be a useful electrophysiological probe to clarify the neurophysiological basis of cognitive processes.

scholarly journals On the Use of Dynamic Bayesian Networks in Reconstructing Functional Neuronal Networks from Spike Train Ensembles

2010 ◽  
Vol 22 (1) ◽  
pp. 158-189 ◽  
Author(s):  
Seif Eldawlatly ◽  
Yang Zhou ◽  
Rong Jin ◽  
Karim G. Oweiss
Keyword(s):  
Bayesian Networks ◽  
Spike Train ◽  
Cortical Neurons ◽  
Effective Connectivity ◽  
Dynamic Bayesian Networks ◽  
Time Varying ◽  
Cortical Networks ◽  
Highly Nonlinear ◽  
Wide Range ◽  
High Level

Coordination among cortical neurons is believed to be a key element in mediating many high-level cortical processes such as perception, attention, learning, and memory formation. Inferring the structure of the neural circuitry underlying this coordination is important to characterize the highly nonlinear, time-varying interactions between cortical neurons in the presence of complex stimuli. In this work, we investigate the applicability of dynamic Bayesian networks (DBNs) in inferring the effective connectivity between spiking cortical neurons from their observed spike trains. We demonstrate that DBNs can infer the underlying nonlinear and time-varying causal interactions between these neurons and can discriminate between mono- and polysynaptic links between them under certain constraints governing their putative connectivity. We analyzed conditionally Poisson spike train data mimicking spiking activity of cortical networks of small and moderately large size. The performance was assessed and compared to other methods under systematic variations of the network structure to mimic a wide range of responses typically observed in the cortex. Results demonstrate the utility of DBN in inferring the effective connectivity in cortical networks.

scholarly journals The Time-varying Networks of the Wrist Extension in Post-stroke Hemiplegic Patients

2020 ◽  
Author(s):  
Fali Li ◽  
Lin Jiang ◽  
Yuqin Li ◽  
Dongfeng Huang ◽  
Yuanling Jiang ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Dynamic Network ◽  
Motor Area ◽  
Time Varying ◽  
Wrist Extension ◽  
Post Stroke ◽  
Motor Behaviors ◽  
Time Varying Networks ◽  
Movement Disability ◽  
Occipital Lobes

Abstract Background: Hemiplegia is a common dysfunction caused by a stroke and leads to movement disability. Although the movement-related oscillation, the lateralization of the movement-related potential, and the event-related desynchronization have been investigated, the dynamic network modalities related to the movements in post-stroke hemiplegic patients are still left unveiled. Methods: In our present study, we designed the motor execution task of the wrist extension, collected the movement-related electroencephalograms, and adopted the adaptive directed transfer function to investigate the dynamic motor networks in post-stroke hemiplegic patients. The corresponding time-varying networks of the wrist extension in post-stroke hemiplegic patients were constructed and then statistically explored. Results: The results demonstrated that the effective connectivity between the stroked motor area and other areas decreased. In contrast, connectivity between non-stroked motor area and other areas was enhanced, especially the frontal and parietal-occipital lobes, to compensate for the dysfunction of the motor behaviors of the stroked patients.Conclusions: These findings help us better understand the time-varying networks underlying the implementation of the motor behaviors of the patients with post-stroke hemiplegia and might provide a reliable biomarker to predict their future rehabilitation.

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.

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