scholarly journals Reduced competition between tool action neighbors in left hemisphere stroke

2019 ◽  
Author(s):  
Frank E. Garcea ◽  
Harrison Stoll ◽  
Laurel J. Buxbaum
Keyword(s):  
Left Hemisphere ◽  
Tool Use ◽  
Neighborhood Effects ◽  
Inferior Frontal Gyrus ◽  
Support Vector ◽  
Single Action ◽  
Limb Apraxia ◽  
Left Hemisphere Stroke ◽  
Hand Action ◽  
Action Errors

AbstractWhen pantomiming the use of tools, patients with limb apraxia after left hemisphere stroke (LCVA) produce more spatiotemporal hand action errors with tools associated with conflicting actions for use versus grasp-to-pick-up (e.g., corkscrew) than tools having a single action for both use and grasp (e.g., hammer). There are two possible accounts for this pattern of results. Reduced performance with ‘conflict’ tools may simply reflect weakened automaticity of use action activation, which is evident only when the use and grasp actions are not redundant. Alternatively, poor use performance may reflect reduced ability of appropriate tool use actions to compete with task-inappropriate action representations. To address this issue, we developed a Stroop-like experiment in which 21 LCVA and 8 neurotypical participants performed pantomime actions in blocks containing two tools that were similar (“neighbors”) in terms of hand action or function, or unrelated on either dimension. In a congruent condition, they pantomimed the use action associated with the visually presented tool, whereas in an incongruent condition, they pantomimed the use action for the other tool in the block. Relative to controls and other task conditions, LCVA participants showed reductions in hand action errors in incongruent relative to congruent action trials; furthermore, the degree of reduction in this incongruence effect was related to the participants’ susceptibility to grasp-on-use conflict in a separate test of pantomime to the sight of tools. Support vector regression lesion-symptom mapping analyses identified the left inferior frontal gyrus, supramarginal gyrus, and superior longitudinal fasciculus as core neuroanatomical sites associated with abnormal performance on both tasks. Collectively, the results indicate that weakened activation of tool use actions in limb apraxia gives rise to reduced ability of these actions to compete for task-appropriate selection when competition arises within single tools (grasp-on-use conflict) as well as between two tools (reduced neighborhood effects).

scholarly journals Structural Disconnection of the Tool Use Network after Left Hemisphere Stroke Predicts Limb Apraxia Severity

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Frank E Garcea ◽  
Clint Greene ◽  
Scott T Grafton ◽  
Laurel J Buxbaum
Keyword(s):  
Left Hemisphere ◽  
Temporal Lobe ◽  
Tool Use ◽  
Critical Issue ◽  
Inferior Parietal Lobule ◽  
Sensory Motor ◽  
Limb Apraxia ◽  
Parietal Lobule ◽  
Skilled Action ◽  
Left Hemisphere Stroke

Abstract Producing a tool use gesture is a complex process drawing upon the integration of stored knowledge of tools and their associated actions with sensory–motor mechanisms supporting the planning and control of hand and arm actions. Understanding how sensory–motor systems in parietal cortex interface with semantic representations of actions and objects in the temporal lobe remains a critical issue and is hypothesized to be a key determinant of the severity of limb apraxia, a deficit in producing skilled action after left hemisphere stroke. We used voxel-based and connectome-based lesion-symptom mapping with data from 57 left hemisphere stroke participants to assess the lesion sites and structural disconnection patterns associated with poor tool use gesturing. We found that structural disconnection among the left inferior parietal lobule, lateral and ventral temporal cortices, and middle and superior frontal gyri predicted the severity of tool use gesturing performance. Control analyses demonstrated that reductions in right-hand grip strength were associated with motor system disconnection, largely bypassing regions supporting tool use gesturing. Our findings provide evidence that limb apraxia may arise, in part, from a disconnection between conceptual representations in the temporal lobe and mechanisms enabling skilled action production in the inferior parietal lobule.

scholarly journals Structural Disconnection of the Tool Use Network After Left Hemisphere Stroke Predicts Limb Apraxia Severity

2020 ◽  
Author(s):  
Frank E. Garcea ◽  
Clint Greene ◽  
Scott T. Grafton ◽  
Laurel J. Buxbaum
Keyword(s):  
Left Hemisphere ◽  
Temporal Lobe ◽  
Tool Use ◽  
Temporal Cortex ◽  
Inferior Parietal Lobule ◽  
Sensory Motor ◽  
Limb Apraxia ◽  
Parietal Lobule ◽  
Skilled Action ◽  
Left Hemisphere Stroke

AbstractProducing a tool use gesture is a complex process drawing upon the integration of stored knowledge of tools and their associated actions with sensory-motor mechanisms supporting the planning and control of hand and arm actions. Understanding how sensory-motor systems in parietal cortex interface with semantic representations of actions and objects in the temporal lobe remains a critical issue, and is hypothesized to be a key determinant of the severity of limb apraxia, a deficit in producing skilled action after left hemisphere stroke. We used voxel-based and connectome-based lesion symptom mapping with data from 57 left hemisphere stroke participants to assess the lesion sites and structural disconnection patterns associated with poor tool use gesturing. We found that structural disconnection between the left inferior parietal lobule, lateral temporal lobe (left middle temporal gyrus) and ventral temporal cortex (left medial fusiform gyrus) predicted the severity of tool use gesturing performance. Control analyses demonstrated that reductions in right-hand grip strength were associated with motor system disconnection, bypassing regions supporting tool use gesturing. Our findings provide causal evidence that limb apraxia may arise, in part, from disconnection of conceptual representations in the temporal lobe from mechanisms enabling skilled action production in the inferior parietal lobule.

scholarly journals The role of conflict, feedback, and action comprehension in monitoring of action errors: Evidence for internal and external routes

2019 ◽  
Author(s):  
Cortney M. Howard ◽  
Louisa L. Smith ◽  
H. Branch Coslett ◽  
Laurel J. Buxbaum
Keyword(s):  
Error Correction ◽  
Production Planning ◽  
Left Hemisphere ◽  
Brain Regions ◽  
Support Vector ◽  
Complex Action ◽  
Gesture Comprehension ◽  
Lesion Symptom Mapping ◽  
Left Hemisphere Stroke

The mechanisms and brain regions underlying error monitoring in complex action are poorly understood, yet errors and impaired error correction in these tasks are hallmarks of apraxia, a common disorder associated with left hemisphere stroke. Accounts of monitoring of language posit an internal route by which production planning or competition between candidate representations provide predictive signals that monitoring is required to prevent error, and an external route in which output is monitored using the comprehension system. Abnormal reliance on the external route has been associated with damage to brain regions critical for sensory-motor transformation and a pattern of gradual error ‘clean-up’ called conduite d’approche (CD). Action pantomime data from 67 participants with left hemisphere stroke were consistent with versions of internal route theories positing that competition signals monitoring requirements. Support Vector Regression Lesion Symptom Mapping (SVR-LSM) showed that lesions in the inferior parietal, posterior temporal, and arcuate fasciculus/superior longitudinal fasciculus predicted action conduite d’approche, overlapping the regions previously observed in the language domain. A second experiment with 12 patients who produced substantial action CD assessed whether factors impacting the internal route (action production ability, competition) versus external route (vision of produced actions, action comprehension) influenced correction attempts. In these ‘high CD’ patients, vision of produced actions and integrity of gesture comprehension interacted to determine successful error correction, supporting external route theories. Viewed together, these and other data suggest that skilled actions are monitored both by an internal route in which conflict aids in detection and correction of errors during production planning, and an external route that detects mismatches between produced actions and stored knowledge of action appearance. The parallels between language and action monitoring mechanisms and neuroanatomical networks pave the way for further exploration of common and distinct processes across these domains.

scholarly journals Shared and Distinct Neuroanatomic Regions Critical for Tool-related Action Production and Recognition: Evidence from 131 Left-hemisphere Stroke Patients

2015 ◽  
Vol 27 (12) ◽  
pp. 2491-2511 ◽  
Author(s):  
Leyla Y. Tarhan ◽  
Christine E. Watson ◽  
Laurel J. Buxbaum
Keyword(s):  
Left Hemisphere ◽  
Mirror Neuron System ◽  
Inferior Frontal Gyrus ◽  
Occipital Cortex ◽  
Neural Substrates ◽  
Middle Temporal Gyrus ◽  
Stroke Patients ◽  
Middle Temporal ◽  
Impaired Performance ◽  
Left Hemisphere Stroke

The inferior frontal gyrus and inferior parietal lobe have been characterized as human homologues of the monkey “mirror neuron” system, critical for both action production (AP) and action recognition (AR). However, data from brain lesion patients with selective impairment on only one of these tasks provide evidence of neural and cognitive dissociations. We sought to clarify the relationship between AP and AR, and their critical neural substrates, by directly comparing performance of 131 chronic left-hemisphere stroke patients on both tasks—to our knowledge, the largest lesion-based experimental investigation of action cognition to date. Using voxel-based lesion-symptom mapping, we found that lesions to primary motor and somatosensory cortices and inferior parietal lobule were associated with disproportionately impaired performance on AP, whereas lesions to lateral temporo-occipital cortex were associated with a relatively rare pattern of disproportionately impaired performance on AR. In contrast, damage to posterior middle temporal gyrus was associated with impairment on both AP and AR. The distinction between lateral temporo-occipital cortex, critical for recognition, and posterior middle temporal gyrus, important for both tasks, suggests a rough gradient from modality-specific to abstract representations in posterior temporal cortex, the first lesion-based evidence for this phenomenon. Overall, the results of this large patient study help to bring closure to a long-standing debate by showing that tool-related AP and AR critically depend on both common and distinct left hemisphere neural substrates, most of which are external to putative human mirror regions.

scholarly journals Right-hemisphere compensation during word production: A single case of left-hemisphere young stroke

2021 ◽  
Author(s):  
Irina Chupina ◽  
Joanna Sierpowska ◽  
Xiaochen Zheng ◽  
Anna Dewenter ◽  
Maria Carla Piastra ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Structural Damage ◽  
Right Hemisphere ◽  
Single Case ◽  
Inferior Frontal Gyrus ◽  
Age Groups ◽  
Word Finding ◽  
Deterministic Tractography ◽  
Left Hemisphere Stroke ◽  
Phonological Retrieval

Our understanding of post-stroke language recovery and underlying neuroplasticity is largely based on older age groups, who have increasing brain pathology and potentially more bilateral language functioning. We present the case of A., a 23 y.o. woman with chronic aphasia from a left-hemisphere stroke. Deterministic tractography indicated that A.’s language-relevant white matter structures were severely damaged. Using magnetoencephalography (MEG), we explored A.’s conceptual preparation and subsequent word planning abilities. Context-driven and Bare picture-naming tasks revealed substantial naming deficits, manifesting as word-finding difficulties and semantic paraphasias about half of the time. Naming was however facilitated by semantically constraining lead-in sentences. Altogether, this pattern indicates intact conceptual preparation but disrupted lexical and phonological retrieval abilities. MEG revealed that A.’s naming-related neural responses differed from that of a matched control. Source localisation showed active but differential recruitment of right-hemisphere structures (300-400 ms post-picture onset) during both correct naming (right temporo-parietal regions) and anomic (right inferior frontal gyrus) attempts. We consider that, despite A.’s young age, the presumed strong degree of language lateralisation and extensive structural damage limited her recovery. Although A.’s right hemisphere responded in a timely manner during word planning, its lexical and phonological retrieval abilities remained modest.

scholarly journals Mapping lesion, structural disconnection, and functional disconnection to symptoms in semantic aphasia

2021 ◽  
Author(s):  
Nicholas E. Souter ◽  
Xiuyi Wang ◽  
Hannah Thompson ◽  
Katya Krieger-Redwood ◽  
Ajay D. Halai ◽  
...  
Keyword(s):  
Cognitive Control ◽  
Left Hemisphere ◽  
Executive Control ◽  
Inferior Frontal Gyrus ◽  
Temporal Cortex ◽  
Executive Dysfunction ◽  
Semantic Retrieval ◽  
Semantic Cognition ◽  
Left Hemisphere Stroke ◽  
Executive Impairment

AbstractPatients with semantic aphasia have impaired control of semantic retrieval, often accompanied by executive dysfunction following left hemisphere stroke. Many but not all of these patients have damage to the left inferior frontal gyrus, important for semantic and cognitive control. Yet semantic and cognitive control networks are highly distributed, including posterior as well as anterior components. Accordingly, semantic aphasia might not only reflect local damage but also white matter structural and functional disconnection. Here we characterise the lesions and predicted patterns of structural and functional disconnection in individuals with semantic aphasia and relate these effects to semantic and executive impairment. Impaired semantic cognition was associated with infarction in distributed left- hemisphere regions, including in the left anterior inferior frontal and posterior temporal cortex. Lesions were associated with executive dysfunction within a set of adjacent but distinct left frontoparietal clusters. Performance on executive tasks was also associated with interhemispheric structural disconnection across the corpus callosum. Poor semantic cognition was associated with small left-lateralized structurally disconnected clusters, including in the left posterior temporal cortex. These results demonstrate that while left- lateralized semantic and executive control regions are often damaged together in stroke aphasia, these deficits are associated with distinct patterns of structural disconnection, consistent with the bilateral nature of executive control and the left-lateralized yet distributed semantic control network.

scholarly journals Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Laura M. Skipper-Kallal ◽  
Elizabeth H. Lacey ◽  
Shihui Xing ◽  
Peter E. Turkeltaub
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Neural Plasticity ◽  
Right Hemisphere ◽  
Inferior Frontal Gyrus ◽  
Lesion Size ◽  
Language Function ◽  
The Right ◽  
Left Hemisphere Stroke ◽  
Aphasia Recovery

The study of language network plasticity following left hemisphere stroke is foundational to the understanding of aphasia recovery and neural plasticity in general. Damage in different language nodes may influence whether local plasticity is possible and whether right hemisphere recruitment is beneficial. However, the relationships of both lesion size and location to patterns of remapping are poorly understood. In the context of a picture naming fMRI task, we tested whether lesion size and location relate to activity in surviving left hemisphere language nodes, as well as homotopic activity in the right hemisphere during covert name retrieval and overt name production. We found that lesion size was positively associated with greater right hemisphere activity during both phases of naming, a pattern that has frequently been suggested but has not previously been clearly demonstrated. During overt naming, lesions in the inferior frontal gyrus led to deactivation of contralateral frontal areas, while lesions in motor cortex led to increased right motor cortex activity. Furthermore, increased right motor activity related to better naming performance only when left motor cortex was lesioned, suggesting compensatory takeover of speech or language function by the homotopic node. These findings demonstrate that reorganization of language function, and the degree to which reorganization facilitates aphasia recovery, is dependent on the size and site of the lesion.

scholarly journals Characterising factors underlying praxis deficits in chronic left hemisphere stroke patients

2020 ◽  
Author(s):  
Elisabeth Rounis ◽  
Ajay Halai ◽  
Gloria Pizzamiglio ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Left Hemisphere ◽  
Cognitive Disorders ◽  
Principal Component ◽  
Lesion Volume ◽  
Semantic Retrieval ◽  
Stroke Patients ◽  
Limb Apraxia ◽  
Lesion Symptom Mapping ◽  
Neuropsychological Tasks ◽  
Left Hemisphere Stroke

AbstractLimb apraxia, a disorder of skilled action not consequent on primary motor or sensory deficits, has traditionally been defined according to errors patients make on neuropsychological tasks. Previous models of the disorder have failed to provide a unified account of patients’ deficits, due to heterogeneity in the patients and tasks used. In this study we implemented principal component analysis (PCA) to elucidate core factors of the disorder in a cohort of 41 unselected left hemisphere chronic stroke patients who were tested on a comprehensive and validated apraxia screen. Three principal components were identified: posture selection, semantic control and multi-demand sequencing. These were submitted to a lesion symptom mapping (VBCM) analysis in a subset of 24 patients, controlled for lesion volume, age and time post-stroke. Although the first component revealed no significant structural correlates, the second and third components were related to regions in the ‘ventro-dorsal’ and ‘ventral’ and ‘dorsal’ pathways, respectively. These results challenge the previously reported distinction between ideomotor and ideational deficits and highlight a significant role of common cognitive functions in the disorder, which include action selection, semantic retrieval, sequencing and response inhibition. Further research using this technique would help elucidate the cognitive processes underlying limb apraxia and their relationship with other cognitive disorders.

scholarly journals Mapping the human praxis network: an investigation of white matter disconnection in limb apraxia

2020 ◽  
Author(s):  
Hannah Rosenzopf ◽  
Daniel Wiesen ◽  
Alexandra Basilakos ◽  
Grigori Yourganov ◽  
Leonardo Bonilha ◽  
...  
Keyword(s):  
White Matter ◽  
Left Hemisphere ◽  
Structural Damage ◽  
Parietal Lobe ◽  
Diffusion Tensor ◽  
Brain Network ◽  
Support Vector ◽  
Precentral Gyrus ◽  
Support Vector Regression Model ◽  
Limb Apraxia

AbstractStroke to the left hemisphere of the brain can cause limb apraxia, a disorder characterised by deficits of higher order motor skills such as the failure to accurately produce meaningful gestures. This disorder provides unique insights into the anatomy of the human praxis system. The present study aimed to identify the structural brain network, that when damaged by stroke, causes limb apraxia. We assessed the ability to perform meaningful gestures with the hand in 101 patients with chronic left hemisphere stroke. Structural damage to white matter fibres was assessed by diffusion tensor imaging. A support vector regression model predicting apraxia based on individual topographies of tract-based fractional anisotropy was utilised to obtain multivariate topographical inference. We found pathological white matter alterations in a densely connected fronto-temporo-parietal network of short and long association fibres to predict limb apraxia deficits. Major disconnection affected temporo-parietal and temporo-temporal connections. Grey matter areas with a high number of disconnections included inferior parietal lobe, middle and superior temporal gyrus, inferior and middle frontal lobe, precentral gyrus, putamen, and caudate nucleus. These results demonstrate the relevance of frontal and inferior parietal regions in praxis, but they also highlight the temporal lobe and its connections to be an important contributor to the human praxis network.

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