Fig 1.
Hindlimbs (red and yellow) and forelimb (green and blue) neuropathways and their corresponding contralateral sensory projections on the right and left cortices are shown.
Left and right Median and Tibial nerves on each limb are stimulated via a pair of subcutaneous needle electrodes. The epicenter of SCI is mid-thoracic (T8). Hindlimb neuropathways originate below the injury site, and their propagations are affected by the midline injury. Whereas the forelimb neuropathways are entirely above the injury site.
Fig 2.
The semi-invasive local hypothermia is delivered to the epicenter of injury (T7-T9) via an M-shaped copper tube connected to the peristaltic pump for circulating cold water around the injury site.
By adjusting the circulating time and temperature of cold water, the desired hypothermia degree can easily be achieved and maintained for an extended time.
Fig 3.
Amplitude of the averaged SSEP signals representing the baseline obtained from one subject.
The stimulation sites are the left forelimb and hindlimb, and the recording sites are contralateral to the side of stimulation from the corresponding areas on the right cortices.
Fig 4.
(a) Amplitude of the averaged SSEP signals obtained from one subject with laminectomy (no injury). The stimulation site is the left forelimb, and the recording site is the corresponding area of the right cortex. (b) Relative amplitude of the averaged SSEP signals obtained from one subject with laminectomy. Statistical t-test analysis with 95% confidence level demonstrates no statistically significant difference between the SSEP relative amplitudes before and after laminectomy.
Fig 5.
(a) Amplitude of the SSEP signals obtained after stimulating the left forelimb from one subject with moderate T8 contusive SCI, followed by normothermia. (b) Relative amplitude of the SSEP signals obtained from group (n = 7) of rats with moderate T8 contusive SCI, followed by normothermia. Statistical t-test analysis with a 95% confidence level demonstrates statistically significant differences between the SSEP relative amplitudes before and after injury in all forelimbs and hindlimbs.
Fig 6.
fMRI recording in rats with moderate T8 contusive SCI and normothermia.
The highest changes of the SSEP amplitudes are observed on day 7 post-SCI for both contralateral and ipsilateral forelimbs cortices regions. Notably, that the SSEP amplitude changes are larger for the contralateral region. Reproduced with permission. [cF: contralateral forelimb region, iF: ipsilateral forelimb region, B: baseline, & D: days post-SCI].
Fig 7.
(a) Amplitude of the SSEPs obtained after stimulating the left forelimb from one subject with moderate T8 contusive SCI, followed by hypothermia. (b) Relative amplitude of the SSEP signals obtained from group (n = 7) of rats with moderate T8 contusive SCI, followed by hypothermia. Statistical t-test analysis with a 95% confidence level demonstrates statistically significant differences between the SSEP relative amplitudes before and after injury in all forelimbs and hindlimbs.
Fig 8.
Shows the relative SSEP amplitudes obtained from stimulating left and right forelimbs of two rodent groups with moderate T8 contusive SCI, followed by normothermia in one group (n = 7) and hypothermia in the second group (n = 7).
It demonstrates that there are statistically significant differences (marked areas) between the SSEP relative amplitudes with normothermia and hypothermia for both right and left forelimbs and days 4 and 7.