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.

scholarly journals Awareness is in the Eye of the Observer: Preserved Third-Person Awareness of Deficit in Anosognosia for Hemiplegia

2021 ◽  
Author(s):  
Sahba Besharati ◽  
Paul Jenkinson ◽  
Michael Kopelman ◽  
Mark Solms ◽  
Valentina Moro ◽  
...  
Keyword(s):  
Social Cognition ◽  
Perspective Taking ◽  
Right Hemisphere ◽  
First Person ◽  
Self Awareness ◽  
Person Perspective ◽  
Right Hemisphere Damage ◽  
Third Person ◽  
Third Person Perspective ◽  
Anosognosia For Hemiplegia

In recent decades, the research traditions of (first-person) embodied cognition and of (third-person) social cognition have approached the study of self-awareness with relative independence. However, neurological disorders of self-awareness offer a unifying perspective to empirically investigate the contribution of embodiment and social cognition to self-awareness. This study focused on a neuropsychological disorder of bodily self-awareness following right-hemisphere damage, namely anosognosia for hemiplegia (AHP). A previous neuropsychological study has shown AHP patients, relative to neurological controls, to have a specific deficit in third-person, allocentric inferences in a story-based, mentalisation task. However, no study has tested directly whether verbal awareness of motor deficits is influenced by either perspective-taking or centrism, and if these deficits in social cognition are correlated with damage to anatomical areas previously linked to mentalising, including the supramarginal and superior temporal gyri and related limbic white matter connections. Accordingly, two novel experiments were conducted with right-hemisphere stroke patients with (n = 17) and without AHP (n = 17) that targeted either their own (egocentric, experiment 1) or another stooge patient’s (experiment 2) motor abilities from a first-or-third person (allocentric in Experiment 2) perspective. In both experiments, neurological controls showed no significant difference between perspectives, suggesting that perspective-taking deficits are not a general consequence of right-hemisphere damage. More specifically, experiment 1 found AHP patients were more aware of their own motor paralysis when asked from a third compared to a first-person perspective, using both group level and individual level analysis. In experiment 2, AHP patients were less accurate than controls in making allocentric, third-person perspective judgements about the stooge patient, but with only a trend towards significance and with no within-group, difference between perspectives. Deficits in egocentric and allocentric third-person perspective taking were associated with lesions in the middle frontal gyrus, superior temporal and supramarginal gyri, with white matter disconnections more predominate in deficits in allocentricity. This study confirms previous clinical and empirical investigations on the selectivity of first-person motor awareness deficits in anosognosia for hemiplegia and experimentally demonstrates for the first time that verbal egocentric 3PP-taking can positively influence 1PP body awareness.

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

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.

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