Lab Log 002: Connectome-Constrained Learning & Locomotion
Executive Summary
We completed the preliminary survey of three primary connectome-derived studies across anatomical baseline, embodied physics, and synaptic plasticity.
1. Whole-Brain Structural Scaffold
- Source: FlyWire Consortium (Nature, Oct 2024; Schlegel et al., Dorkenwald et al.)
- Finding: ~139,255 reconstructed neurons and 54.5M synapses. Serves as ground-truth connectivity matrix.
- Limit: Static graph lacks intrinsic biophysical conductance parameters and neuromodulatory states.
2. Embodied Physics & Closed-Loop Sensory Feedback
- Source: NeuroMechFly v2 (Nature Methods, 2024; Lobato-Ríos et al., Ramdya Lab)
- Finding: Validated that purely descending motor commands produce erratic locomotion without ascending proprioceptive loops and leg adhesion contact physics.
- Limit: Operates primarily on biomechanical coordination; does not simulate adaptive associative learning during navigation.
3. Neuromodulation & Associative Plasticity (PPL1 Dopaminergic Circuit)
- Source: Nature (2024; doi:10.1038/s41586-024-07819-w)
- Finding: Circuit models integrating connectome wiring with spiking dynamics demonstrate that PPL1 dopamine cluster neurons (including PPL1-γ1pedc and PPL1-α3) mediate bidirectional memory gating. Kenyon Cell -> Mushroom Body Output Neuron (MBON) depression drives aversive association, balanced by recurrent feedback.
- Crucial insight: Associative adaptation requires local neuromodulatory feedback rather than global weight backpropagation.
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Benchmark Proposal: Mini-Connectome Olfactory Avoidance (MCOA-01)
- Hypothesis: A simplified connectome-derived subgraph (Projection Neurons -> Kenyon Cells -> MBONs with PPL1 aversive feedback) can replicate empirical conditioned avoidance with zero gradient backpropagation.
- Baseline: Static random feedforward network vs. biologically constrained recurrent MBON feedback.
- Success Criteria: Statistically significant odor discrimination index shift (>0.35) post-pairing with simulated electric shock punishment signal.