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Encephagen: Research Development Report — Final 先天 Phase

Date: April 7, 2026 Author: edvatar (toroleapinc) Repo: https://github.com/toroleapinc/encephagen Duration: 7 days, 37 experiments


1. What We Built

A miniature human newborn simulation: 16,080 spiking neurons controlling a 3D Humanoid body through biologically correct subcortical circuits. Zero learning. Pure innate behavior.

Architecture

CORTEX (16,000 LIF neurons, 80 brain regions)
  - HCP structural connectivity (neurolib80, 6220 continuous weights)
  - T1w/T2w timescale gradient (sensory 10ms → frontal 30ms)
  - Conduction delays from tract lengths (7-238ms)
  - SC-FC validated (r=0.42 against real fMRI)
  - Status: OBSERVER — not controlling the body at birth

BRAINSTEM (hardwired reflex arcs)
  - Righting reflex (tilt → corrective torque)
  - Moro reflex (sudden drop → arms extend then flex, 2 phases)
  - Startle reflex (sudden change → whole-body jerk)
  - Palmar grasp (constant elbow flexion)
  - ATNR/fencing (tilt → asymmetric arm posture)
  - Breathing CPG (~40 breaths/min, abdomen oscillation)
  - General movements (Prechtl's — multi-frequency fidgeting)
  - Stepping drive (upright → activate spinal CPG)
  - Basal ganglia gating (reflex prioritization)

SPINAL CPG (80 LIF neurons, identified interneuron classes)
  - Shox2 rhythm generators (10 neurons, pacemaker)
  - V1 inhibitory (8 neurons, flex-ext alternation)
  - V2a excitatory (6 neurons, drives commissural)
  - V2b inhibitory (8 neurons, flex-ext alternation)
  - V0d inhibitory (6 neurons, left-right alternation)
  - V0v excitatory (6 neurons, left-right alternation)
  - V3 excitatory (6 neurons, symmetry)
  - Motor neurons (20 neurons, flex/ext per side)
  - Architecture: Rybak et al. 2015, Danner et al. 2017, Kiehn 2016
  - Weights: CMA-ES optimized (40 generations, fitness 5.5→2.4 verified)

BODY (MuJoCo Humanoid-v5)
  - 17 actuated joints (torso, 2 arms, 2 legs)
  - Survival: 1.2x baseline (Humanoid) / 2.2x baseline (Walker2d)

Innate Behaviors (10/15 = 67% of real newborn)

Behavior Neural Basis Status
Righting reflex Brainstem vestibular → reticulospinal ✅ Working
Stepping reflex Spinal CPG (80 spiking neurons, V0/V1/V2a/V2b/V3) ✅ Working
Moro reflex Brainstem → bilateral arm extension then flexion ✅ Working
Startle reflex Brainstem reticular → whole body ✅ Working
Palmar grasp Spinal C5-T1 → constant elbow flexion ✅ Working
ATNR/fencing Brainstem → asymmetric arm posture ✅ Working
Breathing Brainstem medullary CPG → abdomen rhythm ✅ Working
General movements Brainstem → multi-frequency whole-body fidgeting ✅ Working
Knee stabilization Spinal → constant slight flexion ✅ Working
Withdrawal Spinal → flex stimulated limb ⚠️ Partial
Babinski, plantar grasp Spinal → toe movements ❌ No toes on body
Rooting, sucking Brainstem trigeminal → mouth ❌ No mouth on body
Swimming Brainstem/spinal → paddling ❌ No water environment

Missing behaviors are due to missing body parts (toes, mouth) and environments (water), NOT missing neural circuits.


2. Key Scientific Findings (37 Experiments)

What macro-scale connectome provides:

  • SC-FC validated dynamics (r=0.42 vs real fMRI) ✅
  • Timescale hierarchy matching Murray 2014 (r=-0.45) ✅
  • Lateralized corrective routing (97% of PD controller without training) ✅

What macro-scale connectome does NOT provide:

  • Cognitive advantage over random wiring (0/33 experiments on validated dynamics)
  • Stimulus propagation through cortex (blocked by all-excitatory long-range)
  • Learning advantage (neither connectome nor random learns at this scale)

What specific circuits DO provide:

  • Sustained gait from 80-neuron spiking CPG with identified interneuron classes ✅
  • This is the fly/worm approach: correct architecture + calibrated weights → behavior

The fundamental lesson:

Behavior comes from specific circuits, not from general connectivity. The macro-scale connectome (80 cortical regions) provides a validated scaffold. Specific subcortical circuits (80 spinal neurons, brainstem reflex arcs) produce the actual behavior. This is biologically correct: newborn behavior is subcortical.


3. Comparison with Other Projects

C. elegans (BAAIWorm) Fruit Fly (Eon 2026) Encephagen
Brain neurons 302 (all identified) 139,255 (all identified) 16,080 (80 cortical populations + 80 spinal identified)
Connectome resolution Synaptic (EM) Synaptic (EM) Macro (dMRI) + spinal identified
Body 3D worm (Sibernetic) NeuroMechFly (MuJoCo) Humanoid-v5 (MuJoCo)
Walking source Connectome + parameter optimization Pre-trained NeuroMechFly controllers CMA-ES optimized spiking CPG
Innate behaviors Chemotaxis, locomotion Grooming, feeding, foraging 10 neonatal reflexes
Learning None None None (innate only)
SC-FC validation Not applicable Not done r=0.42
Weight calibration Parameter optimization EM synapse counts (evolution) CMA-ES (spinal) + Brunel (cortical)

What we do that they don't:

  • SC-FC validated cortex matching real human fMRI
  • T1w/T2w timescale gradient from HCP data
  • Multiple distinct reflexes (10 behaviors, not just locomotion)
  • Cortex as observer with real human connectome (ready for developmental learning)

What they do that we don't:

  • Synaptic-resolution connectome (each neuron identified)
  • Behavior emerging purely from connectome (no hand-coded reflexes)
  • Neurotransmitter identity per synapse

4. The 先天 Ceiling

We have reached the limit of what pure innate structure can produce:

Done (先天):

  • All reflexes a real newborn has (limited by body parts, not neural circuits)
  • Breathing rhythm, general movements, stepping
  • Cortex processing sensory input through validated human connectome
  • 16,080 spiking neurons across 3 hierarchical levels

Requires 后天 (learning):

  • Better balance (real newborns improve over days/weeks)
  • Cortex taking over from brainstem (corticospinal myelination, 2-4 months)
  • Primitive reflexes disappearing (cortex learns to inhibit them)
  • Voluntary movement replacing reflexive movement
  • Any skill beyond hardwired reflexes

The fly project also stopped at innate behavior — no learning. The difference: their innate behavior comes from the connectome; ours comes from hand-coded brainstem + CMA-ES optimized spinal CPG. Both are biologically correct for their scale — the fly has synaptic resolution, we have macro-scale + specific subcortical circuits.


5. How to Run

# Full newborn (Humanoid, all reflexes, spiking CPG, video)
python newborn_full.py --video

# Walker2d version (simpler body, longer survival)
python newborn.py --spiking-cpg --video

# Interactive brain stimulation (no body)
python demo.py

# Generate comparison video
python visualize_humanoid.py

6. Complete Experiment List

# Experiment Key Finding
1-4 Wilson-Cowan phase 1 Degree→hierarchy, wiring→FC
5 Spiking hierarchy Matches Murray 2014
6 STDP habituation Repetition suppression
7-9 Embodied learning Invalidated (motor death)
10 Pendulum learning 5 approaches failed
11 Spontaneous body Rhythmic twitching emerges
12-14 CPG + body 0.98 Hz gait, crawling worm
15-18 Cognitive functions Conditioning, discrimination, memory, integrated
19-20 Walker2d control Brain helps 78%
21-24 Connectome vs random Structure helps organization, not cognition
25-26 SC-FC validation + tuning r=0.388 (tvb96), r=0.42 (neurolib80)
27 Validated connectome vs random (tvb96) 1/5 structure, 3/5 random wins
28 tvb66 tuning Continuous weights, log-transform
29 Validated (neurolib80) 0/4 significant — no structural advantage
30 Innate dynamics Stimulus doesn't propagate (dMRI wall)
31 Learning scaffold Neither brain learns
32 Newborn closed-loop Body too stable
33 Walker2d brain control 210 vs 119 baseline, no structural advantage
34 Pure brain controller Brain = noise (25 steps, 4.5x worse than zero)
35 Lateralized brain 97% of PD controller from pure structure
36 ES spiking CPG optimization Intermittent alternation
37 CMA-ES spiking CPG Sustained oscillation (fitness 5.5, verified 2.4)

7 days. 37 experiments. 16,080 spiking neurons. 10 innate behaviors. The 先天 phase is complete. The newborn is alive.