Recruitment of intrasegmental and propriospinal interneuron networks of forelimb motor circuitry in chronic cervical contusion spinal cord injury

In female rats with chronic C5 hemi-contusion cervical SCI, PTEN inhibition with PAP selectively improved forelimb usage in cylinder paw-preference testing and increased recruitment of PRV-traced interneuron networks.

• Why it matters: Chronic cervical SCI leaves persistent barriers that limit circuit remodeling, and most regenerative therapies are tested only in acute or sub-acute windows, leaving chronic recovery mechanisms underexplored.
• What they did: After C5 hemi-contusion, rats received PTEN antagonist peptide (PAP) at a chronic time point and underwent forelimb behavioral testing; pseudorabies virus (PRV) tracing from ipsilesional triceps mapped local-projecting and propriospinal interneuron recruitment.
• The result: PAP did not improve strength, sensorimotor, or gait-related forelimb measures, but it increased recruitment of PRV-traced interneuron networks and enhanced synaptic input to recruited propriospinal interneurons, implying spinal relay contributions.

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