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1

Task-dependent dissociations between transitive and intransitive gesture representations: the prospects of recovery following right vs. left hemisphere lessions

100%
Kroliczak G.
Acta Neurobiologiae Experimentalis
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2013
|
tom 73
|
nr Suppl.1
There is compelling neuroimaging evidence for a common lefthemisphere praxis representation network supporting the control of meaningful actions. Yet, the idea of dissociable neural systems for tool use (transitive) and intransitive (symbolic) gestures was revived by reports of selective dissociations between imitation and pantomime of transitive and intransitive skills. Because the contribution of recognition and/or visuo-spatial deficits was not directly assessed, this study tested whether distinct representations support transitive and intransitive skills during their visual processing, and later imitation. The outcomes were then compared to the results of verbally-cued gesture pantomimes. Both perception and imitation of the two gesture categories activated common networks, different between the tasks. The areas engaged more during watching transitive pantomimes, and imitation of intransitive gestures, were found outside of these networks. Examples of single case dissociations will be also shown and discussed. All these findings support the idea that transitive gestures are more demanding to process and execute. Yet, they also show that it is imitation of intransitive gestures that relies on modulations outside of the praxis representation network. These outcomes shed some new light on the prospects of recovery following right vs. left, and lateral vs. medial brain lesions.
2

Neural bases of praxis and target-dyrected actions

100%
Kroliczak G.
Acta Neurobiologiae Experimentalis
|
2009
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tom 69
|
nr 3
Neuroimaging evidence (Kroliczak and Frey 2009) indicates that, in right-handers, the left-hemispheric praxis representation network (PRN) constitutes a general domain neural substrate for the planning of meaningful actions, whether or not they involve objects. Less is known about the relationship between PRN and motor dominance in consistent left-handers. Nevertheless, more recent neuroimaging in healthy left-handed adults also shows that planning either transitive/tool use pantomimes or intransitive gestures is associated with increases of activation in the same cortical regions. In addition to the left parietal cortex, however, these increases tend to be more bilateral and involve the dorsal premotor and pre-supplementary motor cortices, as well as the rostral middle frontal gyri. These data suggest that despite reversed motor dominance and more bilateral PRN, planning any meaningful actions might be represented in a common network. The results will be discussed in the context of cortical areas mediating real, target-directed actions.
3

Hemispheric asymmetries for visual processing of tools in left-handers

63%
Michalowski B., Kroliczak G.
Acta Neurobiologiae Experimentalis
|
2013
|
tom 73
|
nr Suppl.1
In typical right-handers, the processing of tool-related information is lateralized to the left hemisphere. Yet, the hemispheric dominance for tools in left-handers is still debated. Since visual half-field (VHF) paradigms provide a reliable measure of cerebral asymmetries, left vs. right hemisphere advantage for man-made object categorization was studied in 17 left-handers (9 women, mean age = 23 years) using a VHF test. The task was to decide whether one of the two bilaterally presented line drawings depicted a tool or non-tool. Given a higher incidence of atypical organization of functions in sinistrals, participants were divided into 2 groups, showing either right or left visual field advantage irrespective of the target objects. Nonetheless, significant effects of visual half-field were found exclusively for tool discrimination. Namely, subjects with the putative typical organization of functions (n=9) showed significantly faster response times for tools correctly categorized in the right visual field (i.e. processed in the left hemisphere) whereas those with atypically organized functions (n=8) responded faster to tools processed in the left visual field (right hemisphere). None of the groups showed any dominance for non-tools. The results indicate that even a simple visual processing of tools can vary significantly across left-handers. It remains to be seen if the observed patterns are linked to language dominance.
4

Cortical asymmetries and the lateralization of gestures and language in left-handers

63%
Bidula S., Kroliczak G.
Acta Neurobiologiae Experimentalis
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2013
|
tom 73
|
nr Suppl.1
It has long been proposed that structural cortical asymmetries may underlie functional lateralization of the human brain. Given that interhemispheric differences in language processing are one of the most pronounced, most studies investigated whether this functional asymmetry has a structural correlate. Recently, it has been demonstrated that it is the insular cortex asymmetry (not the Broca’s area or planum temporale) that is linked to the lateralization of verbal fluency in right-handers. Whether or not this effect can be seen in left-handers is unknown. Moreover, language and gesture representations are co-lateralized. Therefore, if common cortical asymmetries underlie both of these functions then the structure of the insular cortex could also determine them both. Finally, given that gestures are supported by a distributed praxis representation network involving parieto-frontal pathways, other asymmetries may also contribute to the lateralization of this function. Here, we demonstrate that despite the existence of significant asymmetries observed in the superior parietal lobes, only the inter-hemispheric differences in the insular cortex are related to gesture lateralization. Moreover, this study shows that even in left-handed individuals language representation is reflected in insular asymmetry. In sum, the structure of the insula may be paramount to cerebral specialization for both gestures and language.
5

What planning interactions with tools can tell us about bimanuality: an fMRI study

51%
Buchwald M., Nowik A., Kroliczak G.
Acta Neurobiologiae Experimentalis
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2019
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tom 79
|
nr Suppl.1
INTRODUCTION: Using tools according to their functions requires parallel signal processing in numerous and specialized brain areas. So far, fMRI research on neural substrates underlying interactions with tools was mostly restricted to unimanual, pantomimed tool use. AIM(S): The scope of this project was to establish whether representations involved in planning bimanual grasps and subsequent usage of real tools can be distinguished from their functionally equivalent unimanual counterparts. Moreover, we addressed a question whether neural activity within the praxis representation network (PRN), responsible for transforming intentions into actions, is modulated by the number of effectors (hands) required to prepare the appropriate action towards a tool (e.g., a functional grasp). METHOD(S): FMRI contrasts, including repeated-measures ANOVAs and a region-of-interests approach, was adopted. 20 right‑handed participants were scanned in two separate sessions involving a leading vs. a non‑leading/supporting hand. The task was to interact – plan, grasp and execute an action – with bimanual and unimanual tools, and control objects. RESULTS: The greater engagement of the right superior parietal lobule (SPL) suggests that the primary aspect of bimanuality is coordination. Complex motor-to-mechanical transformations for such synchronized movements take place even before grasp and usage onsets. Although PRN was not modulated by tool manuality, SPL was also involved in initiating interactions with bimanual tools. Finally, as the task progressed from the planning to execution, the processing was more extensive and required more neural resources, peaking at the moment of the functional grasp. CONCLUSIONS: Even common actions such as grasping bimanual tools have to be preceded by multifaceted neural signal processing. Furthermore, the brain mechanisms underlying these actions are planned well before the actual behavioral performance of a task. FINANCIAL SUPPORT: Supported by NCN Maestro 2011/02/A/HS6/00174 to GK.
6

When is the brain ready for mental actions? Readiness potential for mental calculations

51%
Ras M., Nowik A. M., Klawiter A., Kroliczak G.
Acta Neurobiologiae Experimentalis
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2019
|
tom 79
|
nr 4
While the preparatory neural mechanisms of real and imagined body movements have been extensively studied, the underpinnings of self‑initiated, voluntary mental acts are largely unknown. Therefore, using electroencephalography (EEG), we studied the time course and patterns of changes in brain activity associated with purely mental processes which start on their own, without an external or interoceptive stimulation. We compared EEG recordings for decisions to perform mental operations on numbers, imagined finger movements, and actual finger movements. In all three cases, we found striking similarities in slow negative shifts of brain electrical activity lasting around 1 s and, therefore, characteristic for readiness potential. These results show that the brain not only needs time to be ready for a purely mental task but also that a required preparatory interval involves neural changes analogical to the ones observed before intentional body movements. As such, the readiness potential represents a universal process of unconscious preparatory brain activity preceding any, including purely mental, voluntary action.
7

Neural bases of actions involving complex motor-to-mechanical tranformations

51%
Ras M., Wyrwa M., Kroliczak G.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr Suppl.1
INTRODUCTION: Each human action involving tools requires transformations of motor responses of hands/ fingers (or different effectors) into mechanical actions of a tool. Whereas tools requiring a relatively low level of motor-to-mechanical transformations were extensively studied, little is known about the neural underpinnings of complex tool use, which involves compound motor‑to‑mechanical transformations. AIM(S): The aim of this study was to investigate the neural bases and mechanisms of functional interactions with tools that are characterized by a high level of motor‑to‑mechanical transformations. METHOD(S): Functional magnetic resonance imaging (fMRI) was utilized in 20 right-handed participants when they prepared and performed multi-phase purposeful actions with real complex tools, with their right and left hands. Specifically, neural activity was investigated during the planning and execution of functional grasp and subsequent usage of complex tools, as compared to actions involving simple tools and control, non‑tool objects. RESULTS: Although specific neural engagement for complex tools, as compared to non-tools, was observed in all phases and concerned nodes of the left-lateralized Praxis Representation Network (PRN), complex tools vs. simple tools, were processed differently at the grasping and tool‑use programming stage. In this phase, the grasping action directed at complex tools involved more the intraparietal sulcus and the nearby subdivisions of the superior parietal lobule. Interestingly, more thorough analyses demonstrated that such translations from motor to mechanical codes also engaged the rostral inferior parietal lobule. CONCLUSIONS: These outcomes point to the prospective character of grasp coding, a process associated with the activity of the intraparietal sulcus, and its cooperation with other hand-centered and tool-centered mechanisms during performance of motor-to-mechanical transformations. FINANCIAL SUPPORT: Supported by NCN Maestro 2011/02/A/HS6/00174 to GK.
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