Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale
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The two-point discrimination threshold (2PDT) has been used to investigate the integration of sensory information, especially in relation to spatial acuity. The 2PDT has been investigated for both innocuous mechanical stimuli and noxious thermal stimuli; however, previous studies used different stimulation modalities to compare innocuous and noxious stimuli. This study investigated the 2PDT in 19 healthy participants, using both thermal (laser) and mechanical stimulation modalities. ⋯ The average NRS for thermal stimuli was 1.6 for innocuous intensities and 4.0 for noxious intensities, while for mechanical stimuli, the average NRS was 0.9 for innocuous intensities and 3.6 for noxious intensities. This study showed that the 2PDT highly depends on both stimulation modality and intensity. Within each modality, noxious intensities modulates the 2PDT differently, i.e., noxious intensities lowers the 2PDT for thermal stimuli, but increases the 2PDT for mechanical stimuli.
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Eye movements have been used extensively to assess information processing and cognitive function. However, significant variability in saccade performance has been observed, which could arise from methodological variations across different studies. For example, prosaccades and antisaccades have been studied using either a blocked or interleaved design, which has a significant influence on error rates and latency. ⋯ Additionally, ROC analysis provided preliminary evidence that pupil size can effectively predict saccade directional errors prior to saccade onset. We propose that task-evoked pupil dilations reflect an increase in preparatory activity for prosaccades and the corresponding cognitive demands associated with interleaved administration mode. Overall, the results highlight the importance that administration mode plays in the design of neurocognitive tasks.
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Acute musculoskeletal pain is associated with reductions in corticomotor output that persists even after pain resolves. Factors that contribute to corticomotor depression following acute pain are unknown. This study examined whether psychological factors, including pain catastrophising, kinesiophobia, and implicit theories of pain, were associated with corticomotor depression following acute experimental muscle pain. ⋯ No relationship was observed with any other psychological variable (p > 0.15). These data provide preliminary support for a relationship between pain-related fear of movement and corticomotor depression in response to acute pain. These findings may have implications for clinical musculoskeletal pain disorders.
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Anticipatory postural adjustments (APAs) are usually generated to minimize the potential postural disturbance induced by predictable external perturbations. Visual information about a perturbation is important for the generation of APAs, but whether people can rely on auditory information to generate APAs is unknown. The aim of this study was to investigate the role of an auditory cue in generating APAs when visual information is not available. ⋯ The results showed that after a short training, participants were able to rely only on the auditory cue to generate APAs comparable to that when the visual information was available. In addition, a training effect was found such that the participants demonstrated stronger APAs and less demands for CPAs through the training trials. The outcome provides a foundation for future studies focusing on the utilization of auditory cues for postural control in older adults and individuals who have vision deficit.
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The purpose of the present study was to investigate the long-term stability of water-referenced GABA and Glx neurometabolite concentrations in the sensorimotor cortex using MRS and to assess the long-term stability of GABA- and glutamate-related intracortical excitability using transcranial magnetic stimulation (TMS). Healthy individuals underwent two sessions of MRS and TMS at a 3-month interval. A MEGA-PRESS sequence was used at 3 T to acquire MRS signals in the sensorimotor cortex. ⋯ There was no significant correlation between MRS and TMS measures at any time point. This study shows that MRS-GABA and MRS-Glx of the sensorimotor cortex have good stability over a 3-month period, with variability across time comparable to that reported in other brain areas. While resting motor threshold, %MSO and CSP were found to be stable and reliable, other TMS measures had greater variability and lesser reliability.