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Contributor(s): Nicholas Strzalkowski; Anthony V. Incognito; Leah R. Bent; Philip J. Millar
Date issued: 2016
Description: Stimulation of high threshold mechanical nociceptors on the skin can modulate efferent sympathetic outflow. Whether low threshold mechanoreceptors from glabrous skin are similarly capable of modulating autonomic outflow is unclear. Therefore, the purpose of this study was to examine the effects of cutaneous afferent feedback from the hand palm and foot sole on efferent muscle sympathetic nerve activity (MSNA). Fifteen healthy young participants (9 male; 25 ± 3 years [range: 22-29]) underwent microneurographic recording of multi-unit MSNA from the right fibular nerve during 2 minutes of baseline and 2 minutes of mechanical vibration (150Hz, 220μm peak-to-peak) applied to the left hand or...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Cale A. Templeton; Nicholas Strzalkowski; Patti Galvin; Leah R. Bent
Date issued: 2018
Description: Aim: To examine tactile sensitivity in the leg and foot sole of below-knee amputees (diabetic n = 3, traumatic n = 1), and healthy control subjects (n = 4), and examine the association between sensation and balance. Method: Vibration perception threshold (VPT; 3, 40, 250Hz) and monofilaments (MF) were used to examine vibration and light touch sensitivity on the intact limb, residual limb, and homologous locations on controls. A functional reach test was performed to assess functional balance. Results: Tactile sensitivity was lower for diabetic amputee subjects compared to age matched controls for both VPT and MF; which was expected due to presence of diabetic peripheral neuropathy. In...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Nicholas Strzalkowski; R. Ayesha Ali; Leah R. Bent
Date issued: 2017
Description: Single unit microneurography was used to record the firing characteristics of the four classes of foot sole cutaneous afferents [fast and slowly adapting type I and II (FAI, FAII, SAI, and SAII)] in response to sinusoidal vibratory stimuli. Frequency (3-250 Hz) and amplitude (0.001-2 mm) combinations were applied to afferent receptive fields through a 6-mm diameter probe. The impulses per cycle, defined as the number of action potentials evoked per vibration sine wave, were measured over 1 s of vibration at each frequency-amplitude combination tested. Afferent entrainment threshold (lowest amplitude at which an afferent could entrain 1:1 to the vibration frequency) and afferent firing...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Joseph Triglav; Erika Howe; Jaskirat Cheema; Blaire Dube; Mark J. Fenske; Nicholas Strzalkowski; Leah R. Bent
Date issued: 2019
Description: Prolonged sitting, common in many workplaces, reduces blood flow to the lower limb and has negative health outcomes. CoreChair is an active-sitting chair that encourages increased movement to help mitigate these outcomes. Physiological and cognitive measures were recorded in ten participants over four hours of sitting in both the CoreChair and a traditional office chair. Sitting in both chairs led to increases in calf circumference (p
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Nicholas Strzalkowski; Ryan M. Peters; J. Timothy Inglis; Leah R. Bent
Date issued: 2018
Description: Cutaneous afferents convey exteroceptive information about the interaction of the body with the environment and proprioceptive information about body position and orientation. Four classes of low-threshold mechanoreceptor afferents innervate the foot sole and transmit feedback that facilitates the conscious and reflexive control of standing balance. Experimental manipulation of cutaneous feedback has been shown to alter the control of gait and standing balance. This has led to a growing interest in the design of intervention strategies that enhance cutaneous feedback and improve postural control. The advent of single-unit microneurography has allowed the firing and receptive field...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Nicholas Strzalkowski; Aaron D. Chau; Liu Shi Gan; Zelma H. T. Kiss
Date issued: 2018
Description: The cerebellum is implicated in the pathophysiology of numerous movement disorders, which makes it an attractive target for noninvasive neurostimulation. Continuous theta burst stimulation (cTBS) can induce long lasting plastic changes in human brain; however, the efficacy of different simulation protocols has not been investigated at the cerebellum. Here, we compare a traditional 50-Hz and a modified 30-Hz cTBS protocols at modulating cerebellar activity in healthy subjects. Seventeen healthy adults participated in two testing sessions where they received either 50-Hz (cTBS50) or 30-Hz (cTBS30) cerebellar cTBS. Cerebellar brain inhibition (CBI), a measure of cerebello-thalamocortical...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Nicholas Strzalkowski; Robyn L. Mildren; Leah R. Bent
Date issued: 2015
Description: Perceptual thresholds are known to vary across the foot sole, despite a reported even distribution in cutaneous afferents. Skin mechanical properties have been proposed to account for these differences; however, a direct relationship between foot sole afferent firing, perceptual threshold, and skin mechanical properties has not been previously investigated. Using the technique of microneurography, we recorded the monofilament firing thresholds of cutaneous afferents and associated perceptual thresholds across the foot sole. In addition, receptive field hardness measurements were taken to investigate the influence of skin hardness on these threshold measures. Afferents were identified as...
Type: article
Appears in collection(s): Science and Technology

Contributor(s): Nicholas Strzalkowski; John J. Triano; Chris K. Lam; Cale A. Templeton; Leah R. Bent
Date issued: 2015
Description: Across the foot sole, there are vibration and monofilament sensory differences despite an alleged even distribution of cutaneous afferents. Mechanical property differences across foot sole sites have been proposed to account for these differences. Vibration (VPT; 3 Hz, 40 Hz, 250 Hz), and monofilament (MF) perception threshold measurements were compared with skin hardness, epidermal thickness, and stretch response across five foot sole locations in young healthy adults (n = 22). Perceptual thresholds were expected to correlate with all mechanical property measurements to help address sensitivity differences between sites. Following this hypothesis, the MedArch was consistently found to be...
Type: article
Appears in collection(s): Science and Technology

MROAR: Mount Royal Open Access Repository