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Somatosensory inputs are sequentially processed across multiple brain regions via cortico-cortical networks. Our recent magnetoencephalography (MEG) study identified specific beta-frequency cortico-cortical networks involved in tactile two-point discrimination (TPD), including those between primary somatosensory cortex (S1) and superior parietal lobule (SPL), and between S1 and angular gyrus (AG). These findings prompted us to investigate whether modifying these networks could influence TPD. We therefore examined the effects of bifocal beta-frequency transcranial alternating current stimulation (tACS) on TPD by specifically targeting the relevant networks. Thirty healthy adults participated in the study, which consisted of five sessions: an MRI scan, MEG recording, and three tACS sessions. Resting-state MEG and somatosensory-evoked magnetic fields were acquired using a 306-channel MEG system. During the intervention, 20-min tACS at each participant’s individual frequency was delivered to personalized targets—either the S1–SPL or S1–AG network—or administered as sham. TPD was automatically assessed at ten distances (0–5.0 mm) before, during, and after tACS. Bifocal beta-frequency tACS selectively modulated TPD thresholds at specific distances under both active conditions. Significant improvements were observed when tACS was applied to the S1–SPL network (3.0, 3.5, and 5.0 mm; all P < 0.049) and the S1–AG network (3.5 mm; all P < 0.046), whereas sham condition produced no significant effects. Electric field modeling confirmed that stimulation selectively targeted either the SPL or the AG, depending on the condition (all P < 0.02). Bifocal beta-frequency tACS targeting the S1–SPL or S1–AG network improves TPD.
Reliable recognition and localization of surgical instruments in endoscopic video recordings are foundational for a wide range of applications in computer- and robot-assisted minimally invasive surgery (RAMIS), including surgical training, skill assessment, and autonomous assistance. However, robust performance under real-world conditions remains a significant challenge. Incorporating surgical context - such as the current procedural phase - has emerged as a promising strategy to improve robustness and interpretability. To address these challenges, we organized the Surgical Procedure Phase, Keypoint, and Instrument Recognition (PhaKIR) sub-challenge as part of the Endoscopic Vision (EndoVis) challenge at MICCAI 2024. We introduced a novel, multi-center dataset comprising thirteen full-length laparoscopic cholecystectomy videos collected from three distinct medical institutions, with unified annotations for three interrelated tasks: surgical phase recognition, instrument keypoint estimation, and instrument instance segmentation. Unlike existing datasets, ours enables joint investigation of instrument localization and procedural context within the same data while supporting the integration of temporal information across entire procedures. We report results and findings in accordance with the BIAS guidelines for biomedical image analysis challenges. The PhaKIR sub-challenge advances the field by providing a unique benchmark for developing temporally aware, context-driven methods in RAMIS and offers a high-quality resource to support future research in surgical scene understanding.
IntroductionIn Sri Lanka, as non-communicable diseases rise, the significance of physical activity is increasingly recognised, particularly in children. The Physical Activity Questionnaire for Older Children (PAQ-C) is widely used and can be considered as one of the best available tools for assessing physical activity in children. However, a validated tool for Sinhala-speaking children in Sri Lanka has been lacking. This study aims to culturally adapt and validate the PAQ-C for Sinhala-speaking children and evaluate its psychometric properties.MethodologyThis cross-sectional study involved 301 schoolchildren (197 males and 104 females) aged 8-11 years, during which the PAQ-C was translated into Sinhala, and a pre-final version was developed. In terms of validity, content validity, that is, the degree to which the content of an instrument is an adequate reflection of the construct to be measured, was assessed using the content validity index. In terms of reliability, test-retest reliability was measured with the intraclass correlation coefficient (ICC).ResultsThe Sinhala version of the PAQ-C demonstrated CVI at both item and scale levels is as one. The ICC was acceptable at 0.83.ConclusionThe Sinhala version of the PAQ-C demonstrates good content validity and acceptable test-retest reliability, affirming its suitability as a cost-effective tool for assessing physical activity levels among Sinhala-speaking children in Sri Lanka and supporting informed interventions and public health strategies in the country.
The cerebellum has been implicated in generating human gait rhythms, and transcranial alternating current stimulation (tACS) at the gait cycle frequency over the cerebellum has been demonstrated to synchronize the gait rhythm. However, whether modulating the tACS frequency to be slower or faster than the normal gait cycle frequency alters the gait rhythms remains unclear. Therefore, we investigated the effects of tACS on the spatiotemporal gait parameters at slower and faster frequencies around the gait cycle frequency over the cerebellum. Eighteen healthy young adults with right-sided dominance performed treadmill walking with tACS under the following stimulation frequency conditions, each applied for 5 min in counterbalanced order: normal gait cycle frequency (100
Humans adapt their gait patterns in response to both internal (e.g., fatigue) and external (e.g., terrain) constraints. Although bipedal locomotion is generally efficient, its stability is reduced on steep or uneven surfaces. Under such conditions, adult hikers often use trekking poles to enhance stability and reduce physical load. In this study, we analysed pole-foot coordination in novice hikers ascending a 4.2 km uphill trail using a gait-classification framework derived from quadrupedal locomotion research. Coordination patterns were characterised by duty factor and diagonality, and gait transition was defined as a shift in the dominant diagonality range across stair-height conditions. When participants ascended moderately high stairs (20 cm), diagonal couplets (diagonality ranges of 40%–50% and 50%–60%) were most frequently observed. These patterns accounted for 36.7% of all steps recorded at 20 cm stairs in the early section of the trail and were similarly frequent (43.4%) in the later section. In contrast, when the stair height increased to approximately 40 cm, lateral couplets (diagonality ranges of 0%–10% and 90%–100%) became dominant, accounting for 33.9% of all steps recorded under this condition. These results indicate that hikers preferentially select pole-foot coordination patterns depending on stair height and show that a diagonal-lateral classification scheme provides a useful basis for describing qualitative coordination transitions in human pole-assisted gait.
