Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale
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We recently demonstrated the emergence of touch-evoked pain (allodynia) during innocuous tactile stimulation of the skin overlying a painful muscle. This effect appeared to depend on a class of low-threshold unmyelinated mechanoafferents, termed C-tactile fibres (CT). In this study, we investigated the peripheral neurocircuitry of allodynia when pain originates in the skin. ⋯ Conversely, the blockade of unmyelinated cutaneous fibres abolished the allodynia (while the myelinated fibres were conducting or not). On the basis of these findings, in addition to our earlier work, we conclude that the allodynic effect of CT-fibre activation is not limited to nociceptive input arising from the muscle, but can be equally realized when pain originates in the skin. These results denote a broader role of CTs in pain modulation.
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We investigated how the influence of natural exploratory gaze behaviour on postural control develops from childhood into adulthood. In a cross-sectional design, we compared four age groups: 6-, 9-, 12-year-olds and young adults. Two experimental trials were performed: quiet stance with a fixed gaze (fixed) and quiet stance with natural exploratory gaze behaviour (exploratory). ⋯ The regularity of COP displacements did not show a clear developmental trend, which indicates that COP dynamics were qualitatively similar across age groups. Together, the results suggest that the contribution of head movement to eye-head saccades decreases with age and that head instability-in part resulting from such gaze-related head movements-is an important limiting factor in children's postural control. The lack of head stabilisation might particularly affect children in everyday activities in which both postural control and visual exploration are required.
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The ability of human sensory systems to integrate information across the different modalities provides a wide range of behavioral and perceptual benefits. This integration process is dependent upon the temporal relationship of the different sensory signals, with stimuli occurring close together in time typically resulting in the largest behavior changes. The range of temporal intervals over which such benefits are seen is typically referred to as the temporal binding window (TBW). ⋯ In the current study, we attempt to elucidate the role that these various factors play in the measurement of this important construct. The results show a strong effect of stimulus type, with the TBW assessed with speech stimuli being both larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes.