Circuit-level neural function: cortical microcircuits, thalamocortical loops, central pattern generators, sensory maps. Bridge between cellular neuroscience and cognition/behaviour.
systems-neuroscience
Cortical microcircuit
Canonical 6-layer column with stereotyped connectivity: L4 input, L2/3 feed-forward, L5 output, L6 thalamocortical feedback. Inhibitory…
Thalamocortical loop
Bidirectional information flow between cortex and thalamic relay nuclei (LGN for vision, VPL for somatosensation). Supports attention,…
Central pattern generator (CPG)
Neural circuit producing rhythmic motor output (locomotion, breathing, swallowing) without sensory drive. Half-centre oscillator of…
Place and grid cells
Hippocampal CA1 place cells fire in specific locations; entorhinal-cortex grid cells form hexagonal firing lattices. Together implement an…
Brain atlas / parcellation
Consensus partition of brain into anatomically and functionally distinct regions (Brodmann 1909, Allen Mouse Brain Atlas, HCP Multimodal…
Receptive field
Region of sensory space whose stimulation modulates a neuron's firing. V1 simple cells have oriented Gabor-like RFs (Hubel-Wiesel 1981…
Population coding
Stimulus encoded across the joint activity of many neurons (not individuals). Decoded by tuning-curve overlap (motor cortex movement…
Neural oscillations
Rhythmic synchronous activity in bands: delta (1–4 Hz, sleep), theta (4–8 Hz, memory), alpha (8–12 Hz, idle cortex), beta (15–30 Hz,…
Wilson-Cowan 2-pop: τ·dE/dt=−E+S(w·inputs); Hopf bifurcation at σ_H=2/(w_EE−w_II)
Wilson-Cowan 2-population neural-mass framework — the canonical coupled-ODE model of cortical excitatory-inhibitory (E-I) dynamics and the…
Friston free-energy principle: F[q]=KL[q||p(z|x)]−log p(x); variational bound on surprise
Friston free-energy principle framework — the canonical information-theoretic model of perception, action, and learning as variational…
Spike-timing-dependent plasticity: Δw(Δt)=A_+·exp(−|Δt|/τ); asymmetric Hebbian learning
Spike-timing-dependent plasticity (STDP) exponential window framework — the canonical spike-timing-based Hebbian learning rule discovered…
WC linearised: Tr(J)=σ(w_EE−w_II)−2; Det(J)=σ²(w_EI·w_IE−w_EE·w_II)+σ(w_II−w_EE)+1; σ_H=2/(w_EE−w_II)
Sympy-exact symbolic witness of the Wilson-Cowan linearised Jacobian trace, determinant, and Hopf-bifurcation boundary in σ. Setup: sg…
Friston KL-Gaussian: F=log(σ_p/σ_q)−1/2+(μ_q²+σ_q²)/(2σ_p²); F=0 at prior=posterior
Sympy-exact symbolic witness of the Friston free-energy Gaussian-KL canonical form, prior-posterior-match anchor, and Gaussian-entropy pin.…
STDP: Δw=A_+·exp(−Δt/τ_+); ∫Δw=A_+·τ_+; balance A_+·τ_+=A_−·τ_−; t_half=τ·log(2)
Sympy-exact symbolic witness of the STDP potentiation exponential canonical form, integrated area, balance condition, half-life, and…
C elegans connectome (White 1986)
White-Southgate-Thomson-Brenner 1986 + 2019 hermaphrodite + male; modern Cook 2019 sex-comparison.
HCP (2010)
Human Connectome Project 2010+ + 1200-subjects + 7T-MRI; modern HCP-developmental + lifespan + UKBB-50000.
Optogenetics (Deisseroth 2005)
Deisseroth-Boyden-Bamberg 2005 + 2010s circuit-dissection; modern step-function + soma-targeted + multi-region.
Neuropixels (2017)
Jun-Steinmetz-Karsh 2017 Neuropixels probe 384-channel; modern 1.0 + 2.0; thousands of single-unit recording.
Allen Brain Atlas (2007)
Allen Institute 2007 Mouse Brain Atlas; modern Allen Cell-Types + Connectivity-Atlas + multi-modal cells.
Hubel-Wiesel (1962)
D Hubel-T Wiesel 1962 (Nobel 1981) V1-receptive-fields; modern hierarchical-feature CNN-DCN deep-learning inspiration.
Place cells (O'Keefe 1971)
J O'Keefe 1971 (Nobel 2014) hippocampal place-cells + Moser-Moser grid-cells 2005; modern cognitive-map attractor-network theory.
Buzsáki theta-γ (1989)
G Buzsáki 1989 hippocampal theta-gamma cross-frequency coupling; modern memory + sleep-replay + brain-atlas Allen Brain.
fMRI (Ogawa 1990)
S Ogawa 1990 BOLD-fMRI; modern 7T human + Connectome 2010 + ABCD 12k-children longitudinal + ML decoding 2023.
Optogenetics (Deisseroth 2005)
K Deisseroth-E Boyden 2005 ChR2-optogenetics; modern miniaturized-fiber + targeted-population + closed-loop circuit-dissection.
C. elegans connectome (1986)
J White-S Brenner 1986 C elegans 302-neuron connectome; modern fly-FlyWire 2024 145k-neurons + mouse-cortex MICrONS 2024.