STRC Calcium Oscillation Acoustic Therapy
Chronic above-threshold sound, delivered through a hearing aid, drives OHC apical Ca²⁺ into the AC1-CREB pathway and tonically up-regulates endogenous STRC transcription. No gene, no drug, no surgery — the therapy is sound itself. Expected STRC protein fold 1.3-2.6× at 45-60 dB LAeq. Mechanism, monotonicity, and parameter robustness (index 0.91) all computationally confirmed (2026-04-20).
The hidden assumption this breaks
Earth treats sound as input to be measured (audiogram, ABR, DPOAE). Nobody treats sound as regulatory signal at the transcriptional layer. Yet Ca²⁺ signalling is one of the best-characterised signal-transduction codes in biology (Dolmetsch 1998, De Koninck & Schulman 1998) and the OHC is uniquely positioned to receive that signal from acoustic input.
The chain (post Phase 1B pivot)
Acoustic input (any broadband sound ≥45 dB)
→ MET channel opening → apical Ca²⁺ rise (to ~500 nM at 45 dB, ~1 µM at 60 dB)
→ Ca₄·CaM binds AC1 → cAMP rises (~350 nM steady)
→ PKA holoenzyme dissociation → PKAc phosphorylates CREB at Ser133
→ CRE-driven STRC transcription (1.3–2.6× induction)
→ endogenous STRC protein increase
→ HTC reformation → Hopf amplifier recovery
For Misha, the relevant allele is the c.4976A>C (E1659A) maternal one. The protein made from this allele is folded; it just binds weakly. More of it → occupancy saturates even weak binding. Sound-driven up-regulation squeezes therapeutic utility out of the mutant allele he already has.
Mechanism notes
Initial Phase 1 model (CaMKII vs CaN frequency-decoder) gave wrong directionality — CaN saturates before CaMKII at OHC sub-µM Ca²⁺, so RBM24-P drops with sound. Pivoted to AC1-CREB in Phase 1B; that pathway is monotonic by construction (AC1 is strictly Ca²⁺-activated via Ca₄·CaM). Details and ODE results in STRC AC1-CREB Monotonic Sound Response. Parameter sensitivity confirmed robust (index 0.91) in STRC AC1-CREB Parameter Robustness.
AM modulation is not the active ingredient. CREB cycles on ~2 min dephosphorylation timescale — too slow to frequency-decode sub-Hz FM. The cochlea is a long-time-constant transcriptional integrator in this regime, not a frequency decoder. Touch Grass acoustic protocol simplifies accordingly: chronic LAeq, not carrier FM.
Acoustic protocol
| Parameter | Target |
|---|---|
| Daily LAeq dose | 45-60 dB, 1-3 h/day minimum (6-8 h ambient target) |
| Carrier frequency | 2-4 kHz (OHC peak sensitivity; matches Misha’s moderate-loss region) |
| Safety ceiling | <85 dB 8-hr LAeq (NIOSH) to avoid NIHL |
| FM / AM shape | none required (content doesn’t matter — LAeq dose is active ingredient) |
| Duty cycle | continuous during waking hours OR 30-60 min dedicated sessions + ambient overlay |
| Expected onset | pCREB 6-24 h; STRC protein 2-4 weeks |
Three delivery modes, escalating in user engagement:
- Ambient overlay — hearing-aid DSP or Touch Grass iOS app ensures input stays ≥45 dB whenever Misha is wearing the aid. All-day coverage, zero user burden.
- Dedicated session — 30-60 min/day of therapeutic soundscape (Touch Grass). Active engagement, higher SNR.
- Hybrid — dedicated dawn/dusk + ambient during day. Recommended for induction phase.
Touch Grass integration — same instrument, new mode
Touch Grass already produces controllable audio across multiple engines (RainStick, OceanDrum, GrainEngine, ModalOscillatorBank). The “STRC therapy mode” is a software flag — no new device. Since content doesn’t matter (Phase 1B finding), any Touch Grass engine output at LAeq ≥45 dB is therapeutic.
Delivery chain
Touch Grass iOS app → iPhone audio → BLE Audio / MFi profile → Hearing aid →
acoustic output into ear canal → tympanic membrane → ossicles →
basilar membrane → OHC stereocilia → MET channels → Ca²⁺ → AC1-CREB → STRC
Firmware integration
- App-level (ship next release): add “STRC Therapy” engine in Touch Grass. Ships as audio update, no hardware change.
- OS-level: no change — iOS ↔ BLE Audio ↔ MFi hearing aid is standard.
- Aid-level (optional): if manufacturer opens DSP hook (Phonak Target, ReSound Smart Fit, etc.), load an “STRC therapy” program that keeps SPL ≥45 dB.
- Monitoring hook: Touch Grass logs LAeq exposure duration per day. Feed weekly DPOAE / monthly ABR.
Session design for Misha
- Induction (first 3 mo): 2 × 45-min daily active sessions + 4-6 h ambient overlay. DPOAE weekly, ABR monthly.
- Maintenance (mo 4+): ambient overlay 4-8 h during waking hours. Dedicated sessions optional.
- Evaluation gate at 6 mo: see kill criteria.
Why the hearing aid is the perfect dosing device
- Worn daily — compliance automatic
- Titrated to Misha’s loss profile — SPL at OHC is correct by design
- Acoustically precise — known frequency response
- Pediatric-safe — decades of pediatric hearing-aid safety data
- Reversible — stop the therapy mode, the dose stops. No residual.
- Titratable — LAeq envelope tunable in minutes per session
The therapy is the device Misha already owns. Zero extra clinical burden.
Kill criteria and go/no-go gates
| Gate | Pass | Kill | Action on kill |
|---|---|---|---|
| Phase 1 (ODE directionality) | Monotonic Ca → STRC protein up | Non-monotonic or wrong sign | Pivot pathway (done 2026-04-20 Phase 1B, passed) |
| Phase 2 (parameter robustness) | Robustness index ≥0.7 | <0.4 | Hypothesis parameter-fragile (done 2026-04-20 Phase 2, index 0.91 passed) |
| Phase 3 (pCREB IHC) | ≥3× OHC nuclear pCREB signal with sound | <1.5× | Not AC1-CREB-mediated — reconsider |
| Phase 4 (STRC mRNA qPCR) | ≥2× STRC mRNA at 6-24 h | <1.5× | CRE-STRC coupling weak — pin K_TXN_MAX_FOLD |
| Phase 5 (chronic 4-wk exposure + ABR) | ≥5 dB DPOAE or ABR improvement @ 2 kHz | No improvement | Pivot to STRC Pharmacochaperone Virtual Screen E1659A or AAV path |
| Phase 6 (pilot in Misha, 6 mo) | ≥5 dB ABR improvement | No improvement | No harm done (sound was always safe); switch to small-molecule or gene therapy |
Resources and validation partners
Compute: trivial — 7-variable ODE runs on MacBook. Already complete.
Wet validation partners:
- Jeffrey Holt lab — OHC explant Ca²⁺ imaging, pCREB IHC, DPOAE. Warm from Derstroff 2026.
- Shu lab — explant capacity (Tang Honghai), in-vivo mouse STRC KO.
- Audiology (Misha) — already scheduled via his audiologist.
Budget:
| Line item | Cost |
|---|---|
| Computational | $0 (complete) |
| pCREB IHC + STRC qPCR in explants | $3-8 k reagents (lab covers labor) |
| Touch Grass firmware (internal) | $0 marginal |
| Audiology monitoring | already covered |
| Total to pilot-in-Misha (6-mo evaluation) | $6-13 k |
By far the cheapest of the three top alien hypotheses. No drug synthesis, no gene delivery, no nanoparticle fabrication — sound through a device he already wears.
Risks and mitigations (condensed)
| Risk | Mitigation |
|---|---|
| E1659A residual affinity too weak — 2× upregulation insufficient | Combine with STRC Pharmacochaperone Virtual Screen E1659A (quantity × affinity additive) |
| Global AC1-CREB activation has off-target footprint | Transcriptome monitoring; restrict to cochlear OHCs via localised SPL dose |
| Chronic exposure damages hearing | Stay <85 dB 8-hr LAeq (NIOSH); audiological monitoring |
| Slow onset (30-day protein t½) → no detectable change for 2-3 months | 6-month evaluation window; chronic maintenance framing |
| Placebo / expectation bias in pilot | Blind LAeq-on/off periods via hearing-aid remote; DPOAE as objective measure |
| Adult OHC expression of AC1 low | Wu 2011 shows AC1 is expressed in adult cochlea; confirm by scRNA-seq atlas |
Why not already published
- Cochlear researchers rarely study intracellular Ca²⁺ → transcription — that vocabulary belongs to immunology (T-cell) and neuroscience (hippocampal LTP).
- Immunologists and neuroscientists rarely study cochlear transcription.
- The bridging question — “can sound regulate cochlear transcription via classical Ca²⁺ signalling?” — falls through the disciplinary gap.
- Sonogenetic researchers focus on AAV + synthetic promoter (Wu 2023, Pan 2018). They don’t ask “can endogenous transcription be driven by ambient sound alone?”
The elegance
Misha wears a hearing aid. The aid receives broadband sound. That sound’s LAeq dose drives AC1-CREB → STRC transcription in the same OHCs that are the target of therapy. The organ receiving the therapy is the organ it treats. Maximum substrate-content alignment. No device, no drug, no DNA to deliver.
Files / Models
Full phase results in child notes:
- STRC AC1-CREB Monotonic Sound Response — Phase 1B ODE, dose-response, wet validation priority
- STRC AC1-CREB Parameter Robustness — Phase 2 OAT sensitivity sweep, robustness index 0.91
- STRC AC1-CREB Phase3 Bifurcation — Phase 3 linear-stability: globally stable, no bistability, true Hill n=4.3 (not 60); sharp-switch claim retracted
Scripts + raw outputs in ~/STRC/models/:
ca_oscillation_rbm24_ode.py/_results.json— Phase 1 (superseded, retained for audit)ca_oscillation_ac1_creb_pivot.py/_results.json— Phase 1B AC1-CREB ODEca_oscillation_phase2_sensitivity.py/.json/.png— Phase 2 robustnessca_oscillation_phase3_bifurcation.py/.json— Phase 3 eigenvalue + hysteresis + smooth-Ca control
Connections
[see-also]STRC AC1-CREB Monotonic Sound Response — Phase 1B mechanism + ODE output[see-also]STRC AC1-CREB Parameter Robustness — Phase 2 sensitivity robustness[see-also]STRC AC1-CREB Phase3 Bifurcation — Phase 3 eigenvalue analysis + bistability-free + true Hill steepness[see-also]STRC AC1-CREB Alternative Hypothesis — pre-computation motivation for the pivot[see-also]STRC RBM24 Regulatory Hypothesis — upstream RNA-level mechanism (complementary framing)[see-also]STRC Pharmacochaperone Virtual Screen E1659A — complementary hypothesis (quantity × affinity additive)[applies]Touch Grass — delivery vehicle and UX[applies]Misha — therapy target[see-also]Jeffrey Holt — primary wet-validation partner[source]2026-04-17-sun-rbm24-strc-splicing — original motivation for the RBM24 splicing angle (now superseded by CREB transcription angle)