Murugan, N. J. | bioRxiv Science

bioRxiv2026

Limb-localized induction of regeneration reshapes brain and amputation-site transcriptional states in adult Xenopus laevis

Limb regeneration requires coordinated tissue reconstruction and nervous system reintegration, yet whether regenerative induction alters brain responses to limb loss remains unclear. We analyzed transcriptomics from the paired brains and amputation sites of adult Xenopus laevis after hindlimb amputation with or without a 24 hour exposure to localized, pro-regenerative multi-drug treatment (MDT) delivered through a wearable bioreactor device. At 24 hours post treatment (24 HPT), MDT brains showed increased vascular and basement membrane transcripts and enrichment of oxidative phosphorylation and mTORC1 programs. In the limb, an exploratory integrated stress response (ISR) score increased at 11 and 24 HPT and returned to control levels by 7 days post-treatment (7 DPT), coinciding with induction of growth differentiation factor 15 (GDF15), a cytokine responsive to mitochondrial stress. We detected no corresponding increase in brain ISR score. At 7 DPT, MDT brains showed enrichment of immune, heme metabolism and biosynthetic programs, reduced synaptic transmission gene expression, and increased gdf15.L. Relative to an external uninjured reference, MDT and amputation only brains showed concordant changes, with treatment modifying selected programs. Cross-species comparative analyses identified partial overlap with an axolotl regenerative glutamatergic signature and separation from selected mammalian injury profiles. These findings reveal cross-tissue responses to regenerative induction and identify candidate mechanisms of brain body communication in biomedically engineered vertebrate limb regeneration.

neuroscience↗

bioRxiv2026

LTP-patterned electromagnetic stimulation induces NMDA receptor-dependent synaptic plasticity in cortical networks

Bioinspired electromagnetic stimulation, in which fields are patterned after endogenous neural activity, have emerged as a potential non-invasive approach for modulating brain dynamics, yet the waveform parameters that determine biological specificity remain poorly defined. Complex electromagnetic patterns modeled after long-term potentiation (LTP) have been reported to alter learning and cortical injury outcomes in vivo, yet whether these fields engage cell-scale synaptic plasticity mechanisms remains unclear. Here, we show that a microtesla-strength electromagnetic field (EMF) patterned after electrophysiological signatures of long-term potentiation produces complex waveform-specific changes in primary cortical network dynamics. Using high-density microelectrode arrays, we show that LTP-patterned EMF stimulation transiently increases spontaneous spikes-per-burst activity relative to a frequency-matched sine-wave EMF exposure and a sham, no field control. This waveform-dependent effect was abolished by NMDA receptor antagonism, indicating dependence on glutamatergic signaling pathways linked to activity-dependent plasticity. LTP-EMF stimulation also dynamically altered evoked network responses, reducing active electrode recruitment to direct electrical stimulation immediately after exposure, with recovery at later timepoints, consistent with a reversible post-induction reorganisation of network state. Transcriptional profiling identified a delayed adaptive response enriched for cellular remodeling pathways, and immunocytochemistry revealed increased co-localization of pre- and post-synaptic markers synaptophysin and PSD-95, a microstructural hallmark of synaptogenesis. Overall, these findings show that weak, bioinspired EMF stimulation can induce waveform-specific changes in cortical network dynamics and engage NMDA-dependent, plasticity-associated mechanisms. This work supports the perspective that temporal waveform structure is a key stimulation parameter for optimizing non-invasive electromagnetic modulation of neural activity.

biophysics↗