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Figure 4 | Journal of Biological Engineering

Figure 4

From: Pushing the science forward: chitosan nanoparticles and functional repair of CNS tissue after spinal cord injury

Figure 4

Somatosensory recordings in control and injured guinea pig spinal cords. The uppermost electrical record is a sample to show the single and averaged evoked potential as they are recorded. This record was produced by stimulation of the tibial nerve and recording the arrival of the ascending evoked potentials (EPs) of ~ 40 msec latency at the sensory motor Cortex. The three bottom traces are single records taken consecutively from the same uninjured animal as detailed in the text, while the top record is an average of these three. Any statistical deviation from baseline is automatically annotated. All data presented below are such averaged signals. The left column shows records taken from a Control animal. The right column shows records obtained from a Chitosan Nanoparticle-treated animal. Note that in both samples, compression injury eliminated transmission of EPs through the cord. Immediately below, the clear recordings of SSEP in both animals were obtained from Median Nerve stimulation/recording. This neural circuit from the forelimb to the sensory cortex is unaffected by injury to the midthoracic spinal cord, and is an internal control for the functioning of the system – eliminating the likelihood of “false negatives”. Note the appearance of weak EPs in only the Chitosan Nanoparticle – treated animal – while electrophysiological functioning in the Control animal were absent throughout the observation period. Reading down, recordings are; A) immediately post injury, B) median nerve control, C) one week post injury, and D) two weeks post injury. The time base is 10 msec per division, with an amplitude of 1.25 microvolts/division.

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