TY  - JOUR
PY  - 2011//
TI  - Human Proprioceptive Adaptations during States of Height-Induced Fear and Anxiety
JO  - Journal of Neurophysiology
A1  - Davis, Justin Robert
A1  - Horslen, Brian C.
A1  - Nishikawa, Kei
A1  - Fukushima, Katie
A1  - Chua, Romeo
A1  - Inglis, John Timothy
A1  - Carpenter, Mark G.
SP  - 3082
EP  - 3090
VL  - 106
IS  - 6
N2  - Clinical and experimental research has demonstrated that the emotional experience of fear impairs postural stability in humans. The current study investigated whether changes in fear and anxiety can also modulate spinal stretch reflexes and the gain of afferent inputs to the primary somatosensory cortex. To do so, two separate experiments were performed on two separate groups of participants while they stood under conditions of low and high postural threat. In Experiment #1, the proprioceptive system was probed using phasic mechanical stimulation of the Achilles tendon while simultaneously recording the ensuing tendon reflexes in the soleus muscle and cortical-evoked potentials over the somatosensory cortex during low and high threat conditions. In Experiment #2, phasic electrical stimulation of the tibial nerve was used to examine the effect of postural threat on somatosensory evoked potentials. Results from Experiment #1 demonstrated that soleus tendon reflex excitability was facilitated during states of height-induced fear and anxiety while the magnitude of the tendon-tap evoked cortical potential was not significantly different between threat conditions. Results from Experiment #2 demonstrated that the amplitudes of somatosensory evoked potentials were also unchanged between threat conditions. The results support the hypothesis that muscle spindle sensitivity in the triceps surae muscles may be facilitated when humans stand under conditions of elevated postural threat, although the presumed increase in spindle sensitivity does not result in higher afferent feedback gain at the level of the somatosensory cortex.<p />  <p>Language: en</p>
LA  - en
SN  - 0022-3077
UR  - http://dx.doi.org/10.1152/jn.01030.2010
ID  - ref1
ER  -