scholarly journals Motor versus body awareness: Voxel-based lesion analysis in anosognosia for hemiplegia and somatoparaphrenia following right hemisphere stroke

Cortex ◽  
2016 ◽  
Vol 83 ◽  
pp. 62-77 ◽  
Author(s):  
Valentina Moro ◽  
Simone Pernigo ◽  
Manos Tsakiris ◽  
Renato Avesani ◽  
Nicola M.J. Edelstyn ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Body Awareness ◽  
Lesion Analysis ◽  
Anosognosia For Hemiplegia ◽  
Right Hemisphere Stroke

scholarly journals Updating Beliefs Beyond the Here-and-Now: The Counter-factual Self in Anosognosia for Hemiplegia

2020 ◽  
Author(s):  
Louise P Kirsch ◽  
Christoph Mathys ◽  
Christina Papadaki ◽  
Penelope Talelli ◽  
Karl Friston ◽  
...  
Keyword(s):  
Bayesian Learning ◽  
Right Hemisphere ◽  
Sensory Information ◽  
Self Awareness ◽  
Belief Updating ◽  
Visuospatial Neglect ◽  
Motor Abilities ◽  
Associated Lesions ◽  
Anosognosia For Hemiplegia ◽  
Right Hemisphere Stroke

The syndrome of anosognosia for hemiplegia (AHP), or the lack of awareness for one’s paralysis following right hemisphere stroke, can provide unique insights into the neurocognitive mechanisms of self-awareness. Yet it remains unclear whether AHP is a modality-specific deficit of sensorimotor monitoring, or whether domain-general processes of attention and belief-updating converge to cause AHP. Using a Bayesian learning framework, we formalised and empirically investigated the hypothesis that failures to update anosognosic beliefs can be explained by abnormalities in the relative uncertainty (i.e. precision) ascribed to prior beliefs versus sensory information in different contexts. We designed a new motor belief-updating task that manipulated both the temporal (prospective and retrospective) and spatial (hemispace most affected by inattention and hemispace less affected by inattention) conditions in which beliefs had to be updated, and we validated its sensitivity to AHP in 26 patients with right hemisphere stroke. We then computed and empirically tested two different Bayesian predictors of prospective beliefs using two proxies for precision in AHP patients: (i) standardised, neuropsychological measures of objective attention abilities, i.e. visuospatial neglect scores, and (ii) subjective uncertainty reports, i.e. confidence ratings. Our results suggest that while neglect does not affect local, sensorimotor error monitoring, it does seem to affect the degree to which observed errors are used to update more general, prospective beliefs about counterfactual motor abilities in AHP. Difficulties in such ‘counterfactual’ belief-updating were associated with disruptions in tracts of the ventral attentional network (i.e. superior longitudinal fasciculus connecting the temporo-parietal junction and ventral frontal cortex) and associated lesions to the insula, inferior parietal cortex and superior temporal regions. These results suggest that self-awareness extends beyond local, retrospective monitoring, requiring also salience-based, convergence of beliefs about the self that go beyond the ‘here-and-now’ of sensorimotor experience.

Map learning may be impaired after right-hemisphere stroke

2010 ◽  
Author(s):  
Peii Chen ◽  
C. Priscilla Galarza ◽  
Kimberly Hreha ◽  
Tara Miceli ◽  
Anna M. Barrett
Keyword(s):  
Right Hemisphere ◽  
Map Learning ◽  
Right Hemisphere Stroke

scholarly journals Is Lateropulsion Really Related with a Specific Lesion of the Brain?

2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Kyoung Lee ◽  
Sang Yoo ◽  
Eun Ji ◽  
Woo Hwang ◽  
Yeun Yoo ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Parietal Lobe ◽  
Inferior Frontal Gyrus ◽  
Brain Lesions ◽  
Vertical Posture ◽  
Lesion Volume ◽  
Precentral Gyrus ◽  
Stroke Patients ◽  
The Right ◽  
Right Hemisphere Stroke

Lateropulsion (pusher syndrome) is an important barrier to standing and gait after stroke. Although several studies have attempted to elucidate the relationship between brain lesions and lateropulsion, the effects of specific brain lesions on the development of lateropulsion remain unclear. Thus, the present study investigated the effects of stroke lesion location and size on lateropulsion in right hemisphere stroke patients. The present retrospective cross-sectional observational study assessed 50 right hemisphere stroke patients. Lateropulsion was diagnosed and evaluated using the Scale for Contraversive Pushing (SCP). Voxel-based lesion symptom mapping (VLSM) analysis with 3T-MRI was used to identify the culprit lesion for SCP. We also performed VLSM controlling for lesion volume as a nuisance covariate, in a multivariate model that also controlled for other factors contributing to pusher behavior. VLSM, combined with statistical non-parametric mapping (SnPM), identified the specific region with SCP. Lesion size was associated with lateropulsion. The precentral gyrus, postcentral gyrus, inferior frontal gyrus, insula and subgyral parietal lobe of the right hemisphere seemed to be associated with the lateropulsion; however, after adjusting for lesion volume as a nuisance covariate, no lesion areas were associated with the SCP scores. The size of the right hemisphere lesion was the only factor most strongly associated with lateropulsion in patients with stroke. These results may be useful for planning rehabilitation strategies of restoring vertical posture and understanding the pathophysiology of lateropulsion in stroke patients.

Characterizing Subtypes and Neural Correlates of Receptive Aprosodia in Acute Right Hemisphere Stroke

Cortex ◽  
2021 ◽  
Author(s):  
Shannon M. Sheppard ◽  
Erin L. Meier ◽  
Alexandra Zezinka Durfee ◽  
Alex Walker ◽  
Jennifer Shea ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Neural Correlates ◽  
Right Hemisphere Stroke
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