Radek Ptak

Working memory (WM) is a core component of higher‐order cognition, and its impairment is a common consequence of stroke. While traditional lesion‐symptom mapping highlights focal damage, it often overlooks alterations in large‐scale brain network dynamics. This study investigated WM deficits through functional connectivity (FC) analyses of frontoparietal networks in 34 patients with right hemisphere (RH) stroke and 35 healthy controls. Resting‐state fMRI was used to examine region‐of‐interest and whole‐brain seed‐to‐voxel FC in relation to WM performance on verbal and spatial N ‐back tasks. Compared to controls, stroke patients exhibited disrupted FC‐WM associations, characterized by reduced intrahemispheric FC between anterior and posterior RH regions, which correlated with poorer WM performance. Notably, enhanced interhemispheric FC, particularly between the right middle and inferior frontal gyri and contralateral parietal cortices, was positively associated with WM accuracy, suggesting compensatory engagement of the intact hemisphere. No performance differences were observed between task modalities, supporting the involvement of domain‐general WM mechanisms. These findings highlight the role of early network‐level reorganization in shaping cognitive outcomes post‐stroke. Specifically, WM deficits appear to result not solely from structural damage but from altered FC patterns, where reduced intrahemispheric connectivity may be mitigated by adaptive interhemispheric recruitment.

Background: The interplay between the ventral attention network (VAN) and dorsal attention network (DAN) is crucial for attentional control, particularly in disengagement processes. While task‐based fMRI studies have extensively characterized their roles, less is known about whether intrinsic connectivity patterns during rest within these networks predict individual differences in attentional disengagement. This study investigates the relationship between resting‐state functional VAN‐DAN connectivity and disengagement efficiency. Methods: An initial sample of 85 healthy participants completed a spatial cueing task, assessing attentional disengagement through reaction time differences between valid and invalid cue trials. Resting‐state fMRI data were collected and analyzed using seed‐based connectivity methods. Functional connectivity between key VAN and DAN regions—frontal eye fields (FEF), intraparietal sulcus (IPS), inferior frontal gyrus (IFG), and supramarginal gyrus (SMG)—was examined in relation to a disengagement index, representing cue validity effects. Results: Participants exhibited slower responses to invalidly cued targets, with a greater disengagement cost in the left visual field. Functional connectivity analyses revealed that VAN regions, particularly the right IFG and SMG, showed stronger associations with attentional disengagement than DAN regions. Increased FC with occipito‐temporal areas correlated with heightened validity effects in the left hemifield, while greater connectivity with medial parietal and cingulate regions was linked to reduced disengagement asymmetry. Interhemispheric connectivity also played a modulatory role in attentional control. Conclusion: These findings underscore the role of VAN over DAN in attentional disengagement, emphasizing the right IFG and SMG in reorienting attention. Greater connectivity with occipito‐temporal regions may hinder disengagement, while enhanced functional connectivity with medial cortical areas facilitates adaptive shifts in attention. This study highlights the importance of intrinsic VAN‐DAN interactions in shaping attentional control and provides insights into the neural mechanisms underlying disengagement efficiency.

Mental transformations, such as mental rotation, rely on motor representations and engage neural processes similarly to physical actions. Neuroimaging studies reveal that mental rotation activates the occipito-parietal cortex and motor-related areas, with differences based on whether stimuli are bodily or non-bodily. These findings emphasize the role of frontoparietal networks in mental rotation, similar to those used in motor planning. This study investigated whether resting-state functional connectivity of the left lateral prefrontal cortex (lPFC), a region linked to motor planning, and other functional brain networks predicts mental rotation performance. Fifty-nine healthy individuals underwent functional magnetic resonance imaging (fMRI) to capture resting-state blood oxygenation level dependent (BOLD) activity and completed mental rotation tasks using bodily (hands) and non-bodily (letters) stimuli. Performance in both mental rotation tasks exhibited the expected peak of difficulty with completely inverted stimuli, which require a mental transformation of 180 degrees. At the functional level, mental rotation error rates correlated with lPFC connectivity to the default mode network (DMN). However, this relationship was negative and much stronger for the hands task, indicating that lPFC-DMN interactions were associated with poorer mental rotation performance. These results indicate that effective mental rotation relies on the functional disconnection of the DMN from motor planning networks. The findings highlight the significance of studying resting-state functional connectivity to understand how brain networks contribute to cognitive functions and how their interactions can enhance or impair performance. This work advances our understanding of the neural mechanisms underlying mental rotation, emphasizing the interplay between motor cognition and resting-state dynamics.

Purpose: Frontoparietal networks (FPN) are well‐recognized for their role in high‐level cognition, including mental imagery, executive control, and working memory (WM). A prevailing hypothesis advances that these functions evolved from fundamental motor abilities, such as action planning and motor control. However, whether sensorimotor regions of these FPN contribute to the executive components of WM, and whether this contribution is dependent on task modality, remains underexplored.Method: This study applied analyses of resting‐state functional connectivity (rs‐FC) to investigate the contribution of FPN regions to WM that have an established role in motor planning. In a sample of 60 healthy individuals, we explored whether performance in verbal and spatial N‐back WM tasks is associated with rs‐FC of frontoparietal brain regions that exhibit increased activation during motor planning.Finding: Comparing verbal and spatial N‐back tasks revealed that verbal WM was associated with stronger connectivity between the left medial superior frontal gyrus and left inferior parietal lobule (IPL), as well as the right IPL and the left superior parietal lobule. In contrast, spatial WM was linked to stronger connectivity between the right middle frontal and inferior temporal gyrus, as well as the left occipital pole and postcentral gyrus.Conclusion: These findings reveal distinct FC patterns underlying verbal and spatial WM and highlight the contribution of brain regions that are important for motor planning to modality‐specific WM processes, such as information updating.

Frontoparietal networks (FPN) are well‐recognized for their role in high‐level cognition, including mental imagery, executive control, and working memory (WM). A prevailing hypothesis advances that these functions evolved from fundamental motor abilities, such as action planning and motor control. However, whether sensorimotor regions of these FPN contribute to the executive components of WM, and whether this contribution is dependent on task modality, remains underexplored. This study applied analyses of resting‐state functional connectivity (rs‐FC) to investigate the contribution of FPN regions to WM that have an established role in motor planning. In a sample of 60 healthy individuals, we explored whether performance in verbal and spatial N‐back WM tasks is associated with rs‐FC of frontoparietal brain regions that exhibit increased activation during motor planning. Comparing verbal and spatial N‐back tasks revealed that verbal WM was associated with stronger connectivity between the left medial superior frontal gyrus and left inferior parietal lobule (IPL), as well as the right IPL and the left superior parietal lobule. In contrast, spatial WM was linked to stronger connectivity between the right middle frontal and inferior temporal gyrus, as well as the left occipital pole and postcentral gyrus. These findings reveal distinct FC patterns underlying verbal and spatial WM and highlight the contribution of brain regions that are important for motor planning to modality‐specific WM processes, such as information updating.

Visual field loss and visuospatial neglect are frequent consequences of cerebral stroke. They often have a strong impact on independence in many daily activities. Rehabilitation aiming to decrease these disabilities is therefore important, and several techniques have been proposed to foster awareness, compensation, or restitution of the impaired visual field. We here describe a rehabilitation intervention using adapted boxing therapy that was part of a pluridisciplinary intervention tailored for a particular case. A 58-year-old man with left homonymous hemianopia (HH) and mild visuospatial hemineglect participated in 36 sessions of boxing therapy six months after a right temporo-occipital stroke. Repeated stimulation of his blind and neglected hemifield, and training to compensate for his deficits through improved use of his healthy hemifield were performed through boxing exercises. The patient showed a stable HH before the beginning of the training. After six months of boxing therapy, he reported improved awareness of his visual environment. Critically, his HH had evolved to a left superior quadrantanopia and spatial attention for left-sided stimuli had improved. Several cognitive functions and his mood also showed improvement. We conclude that boxing therapy has the potential to improve the compensation of visuospatial impairments in individual patients with visual field loss.