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Right hemisphere brain damage impairs strategy updating. Cereb Cortex 22
, 2012
"... Our behavior is predicated on mental models of the environment that must be updated to accommodate incoming information. We had 13 right-brain--damaged (RBD) patients and 10 left-brain--damaged (LBD) patients play the children’s game ‘‘rock, paper, scissors’ ’ against a computer opponent that covert ..."
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Our behavior is predicated on mental models of the environment that must be updated to accommodate incoming information. We had 13 right-brain--damaged (RBD) patients and 10 left-brain--damaged (LBD) patients play the children’s game ‘‘rock, paper, scissors’ ’ against a computer opponent that covertly altered its strategy. Healthy age-matched controls and LBD patients quickly detected extreme departures from uniform play (‘‘paper’ ’ chosen on 80 % of trials), but the RBD patient group did not. Seven RBD patients presented with neglect and although this was associated with greater impairment in strategy updating, there were exceptions: 2 of 7 neglect patients performed above the median of the patient group and 1 of the 6 nonneglect participants was severely impaired. Although speculative, lesion analyses contrasting high and low performing patients showed that severe impairments were associ-ated with insula and putamen lesions. Interestingly, relative to the controls, the LBD group tended to ‘‘maximize’ ’ choices in the strongly biased condition (i.e., optimal strategy chosen on 100 % of the trials), whereas controls ‘‘matched’ ’ the computer’s strategy (i.e., optimal strategy chosen on 80 % of the trials). We conclude that RBD leads to impaired updating of mental models to exploit environmental changes.
unknown title
, 2009
"... Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or ..."
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Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or
Behavioral/Systems/Cognitive Convergence between Lesion-SymptomMapping and Functional Magnetic Resonance Imaging of Spatially Selective Attention in the Intact Brain
"... The parietal regions implicated in spatially selective attention differ between patient lesion studies and functional imaging of the intact brain.We aimed to resolve this discordance. In a voxel-based lesion-symptommapping study in 20 ischemic stroke patients, we applied the samecognitive subtractio ..."
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The parietal regions implicated in spatially selective attention differ between patient lesion studies and functional imaging of the intact brain.We aimed to resolve this discordance. In a voxel-based lesion-symptommapping study in 20 ischemic stroke patients, we applied the samecognitive subtractionapproachas in23healthyvolunteerswhounderwent functionalmagnetic resonance imaging (fMRI)using identical tasks and stimuli. An instructive central cue directed attention to one visual quadrant. After a brief delay, a grating appeared in that quadrant togetherwith an irrelevant grating in anuncuedquadrant. Subjects had to discriminate the orientation of the grating in the cued quadrant. Patients with a right inferior parietal lesion were significantly more impaired during contralesional versus ipsilesional orienting when stimuli were bilateral and symmetrical than when stimuli occupied diagonally opposite quadrants or two quadrants within the samehemifield. In one area, the lesion-volumemapoverlappedwith the activitymapobtained in healthy volunteers: the lower bank of the middle third of the right intraparietal sulcus (IPS). In an additional 37 healthy fMRI subjects, we disentangled the effects of symmetry, bilaterality, and spatial configuration between stimuli on activity in the volume of overlap. Only the axis of configuration between stimuli had a significant effect, with highest activity when the configuration axis was horizontal. This constitutes converging evidence from patients and cognitively intact subjects that the lower bank of the middle third of the right IPS critically contributes to attentive selection between competing stimuli in a spatially anisotropic manner. Key words: attention; neglect; extinction; fMRI; stroke; VLSM
Cerebral Cortex doi:10.1093/cercor/bhr351 Right Hemisphere Brain Damage Impairs Strategy Updating
"... Our behavior is predicated on mental models of the environment that must be updated to accommodate incoming information. We had 13 right-brain--damaged (RBD) patients and 10 left-brain--damaged (LBD) patients play the children’s game ‘‘rock, paper, scissors’ ’ against a computer opponent that covert ..."
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Our behavior is predicated on mental models of the environment that must be updated to accommodate incoming information. We had 13 right-brain--damaged (RBD) patients and 10 left-brain--damaged (LBD) patients play the children’s game ‘‘rock, paper, scissors’ ’ against a computer opponent that covertly altered its strategy. Healthy age-matched controls and LBD patients quickly detected extreme departures from uniform play (‘‘paper’ ’ chosen on 80 % of trials), but the RBD patient group did not. Seven RBD patients presented with neglect and although this was associated with greater impairment in strategy updating, there were exceptions: 2 of 7 neglect patients performed above the median of the patient group and 1 of the 6 nonneglect participants was severely impaired. Although speculative, lesion analyses contrasting high and low performing patients showed that severe impairments were associ-ated with insula and putamen lesions. Interestingly, relative to the controls, the LBD group tended to ‘‘maximize’ ’ choices in the strongly biased condition (i.e., optimal strategy chosen on 100 % of the trials), whereas controls ‘‘matched’ ’ the computer’s strategy (i.e., optimal strategy chosen on 80 % of the trials). We conclude that RBD leads to impaired updating of mental models to exploit environmental changes.
unknown title
"... Spatial neglect is a neurological condition characterized by a breakdown of spatial cognition contralateral to hemispheric damage. Deficits in spatial attention toward the contrale-sional side are considered to be central to this syndrome. Brain lesions typically involve right fronto-parietal cortic ..."
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Spatial neglect is a neurological condition characterized by a breakdown of spatial cognition contralateral to hemispheric damage. Deficits in spatial attention toward the contrale-sional side are considered to be central to this syndrome. Brain lesions typically involve right fronto-parietal cortices mediating attentional functions and subcortical connections in underlying white matter. Convergent findings from neuroimaging and behavioral studies in both animals and humans suggest that the cholinergic system might also be critically implicated in selective attention by modulating cortical function via widespread projections from the basal forebrain. Here we asked whether deficits in spatial attention associated with neglect could partly result from a cholinergic deafferentation of cortical areas subserving attentional functions, and whether such disturbances could be alleviated by pro-cholinergic therapy. We examined the effect of a single-dose transdermal nicotine treatment on spa-
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"... Effects of pro-cholinergic treatment in patients suffering from spatial neglect LUCAS BALOGH, Nadia, et al. Spatial neglect is a neurological condition characterized by a breakdown of spatial cognition contralateral to hemispheric damage. Deficits in spatial attention toward the contralesional side ..."
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Effects of pro-cholinergic treatment in patients suffering from spatial neglect LUCAS BALOGH, Nadia, et al. Spatial neglect is a neurological condition characterized by a breakdown of spatial cognition contralateral to hemispheric damage. Deficits in spatial attention toward the contralesional side are considered to be central to this syndrome. Brain lesions typically involve right fronto-parietal cortices mediating attentional functions and subcortical connections in underlying white matter. Convergent findings from neuroimaging and behavioral studies in both animals and humans suggest that the cholinergic system might also be critically implicated in selective attention by modulating cortical function via widespread projections from the basal forebrain. Here we asked whether deficits in spatial attention associated with neglect could partly result from a cholinergic deafferentation of cortical areas subserving attentional functions, and whether such disturbances could be alleviated by pro-cholinergic therapy. We examined the effect of a single-dose transdermal nicotine treatment on spatial neglect in 10 stroke patients in a double-blind placebo-controlled protocol, using a standardized battery of neglect tests. [...] LUCAS BALOGH, Nadia, et al. Effects of pro-cholinergic treatment in patients suffering from spatial neglect. Frontiers in Human Neuroscience, 2013, vol. 7, p. 574 DOI: 10.3389/fnhum.2013.00574 PMID: 24062674
Advance Access publication March 12, 2009 No Neglect-Specific Deficits in Reaching Tasks
"... It is well established that patients with hemispatial neglect present with severe visuospatial impairments, but studies that have directly investigated visuomotor control have revealed diverging results, with some studies showing that neglect patients perform relatively better on such tasks. The pre ..."
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It is well established that patients with hemispatial neglect present with severe visuospatial impairments, but studies that have directly investigated visuomotor control have revealed diverging results, with some studies showing that neglect patients perform relatively better on such tasks. The present study compared the visuomotor performance of patients with and without neglect after right-hemisphere stroke with those of age-matched controls. Participants were asked to point either directly towards targets or halfway between two stimuli, both with and without visual feedback during movement. Although we did not find any neglect-specific im-pairment, both patient groups showed increased reaction times to leftward stimuli as well as decreased accuracies for open loop leftward reaches. We argue that these findings agree with the view that neglect patients code spatial parameters for action veridically. Moreover, we suggest that lesions in the right hemisphere may cause motor deficits irrespective of the presence of neglect and we performed an initial voxel-lesion symptom analysis to assess this. Lesion-symptom analysis revealed that the reported deficits did not result from damage to neglect-associated areas alone, but were further associated with lesions to crucial nodes in the visuomotor control network (the basal ganglia as well as occipito-parietal and frontal areas).
