tooluniverse-neuroscience

name tooluniverse-neuroscience description Neuroscience research workflows: neuroanatomy, neural circuits, neurotransmitter biology, neurological/psychiatric disease genetics, neural-protein function. Uses Allen Brain Atlas, WormBase (C. elegans connectome), UniProt for neural proteins, PubMed for primary literature. Use for brain-region biology, neural development, neurodegeneration mechanisms (Alzheimer's, Parkinson's, ALS), and synaptic-protein characterization. disable-model-invocation true Neuroscience Research Skill KEY PRINCIPLES : LOOK UP, DON'T GUESS — use PubMed/EuropePMC for neuroanatomy facts, WormBase for C. elegans connectome data, UniProt for neural protein properties. Verify claims with literature before answering. Use Python computation for quantitative neuroscience problems. LOOK UP, DON'T GUESS When uncertain about any neuroscience fact — brain region function, neural circuit connectivity, ion channel properties, neurotransmitter receptor subtypes — SEARCH databases first. A PubMed-verified answer is always more reliable than reasoning from memory. This is especially critical for neuroanatomy, where structures have precise boundaries and connectivity patterns that are easy to confuse. 1. Computational Neuroscience Reasoning Rate-Based Models Firing rate of a neuron: r = f(I - theta), where I = total synaptic input, theta = threshold, f = transfer function (sigmoid, ReLU, or threshold-linear) Balanced excitation/inhibition: in cortical networks, excitatory and inhibitory inputs are large but nearly cancel, leaving a small net drive Population rate equations: tau * dr/dt = -r + f(W*r + I_ext), where W = connectivity matrix Steady-state analysis: set dr/dt = 0, solve r = f(W*r + I_ext) — use fixed-point iteration or Newton's method Integrate-and-Fire Neurons Membrane voltage dynamics: tau_m * dV/dt = -(V - V_rest) + R_m * I(t) When V reaches threshold V_th: emit spike, reset to V_reset, enter refractory period tau_ref Firing rate for constant input: r = 1 / (tau_ref + tau_m * ln((R_m I - V_reset) / (R_m I - V_th))) [valid when R_m*I > V_th] For sub-threshold input: neuron requires fluctuations (noise) to fire — noise-driven regime Key variants: LIF (leaky), EIF (exponential), AdEx (adaptive exponential), Izhikevich (2D with recovery variable) Synaptic Plasticity STDP (Spike-Timing-Dependent Plasticity): Pre-before-post (positive dt): LTP (potentiation) — synapse strengthened Post-before-pre (negative dt): LTD (depression) — synapse weakened Window shape: typically exponential decay with tau_+ ~ 20ms (LTP) and tau_- ~ 20ms (LTD) Hebbian learning : "cells that fire together wire together" — correlation-based; unstable without normalization BCM theory : sliding threshold — low postsynaptic activity → LTD, high → LTP; threshold slides with average activity Homeostatic plasticity : synaptic scaling adjusts all synapses multiplicatively to maintain target firing rate Network Dynamics Mean-field theory : replace individual neurons with population-averaged firing rates; self-consistency equation r = f(J r sqrt(K) + I_ext) where K = number of connections Balanced networks : E/I balance emerges when sqrt(K)*J ~ O(1); firing rate ~ (mu - theta) / tau where mu = mean input, theta = threshold Chaos transition : in random networks, chaos onset at g_c = 1 (gain parameter); above g_c, autocorrelation decays, Lyapunov exponent > 0 Oscillations : gamma (30-80 Hz) from E-I loops (PING model), theta (4-8 Hz) from slower inhibition or hippocampal circuits, alpha (8-12 Hz) from thalamo-cortical loops Quantitative Problem-Solving Strategy Identify the model type (single neuron, network, plasticity rule) Write down the governing equations with all parameters ALWAYS use Python for multi-step calculations — do not attempt mental arithmetic Check units: voltages in mV, currents in nA or pA, time constants in ms, rates in Hz Sanity check: cortical firing rates are typically 1-20 Hz; tau_m ~ 10-20 ms; V_th ~ -50 mV 2. Neuroanatomy Reasoning CRITICAL: Look Up Neuroanatomy Brain region functions, boundaries, and connectivity are precise anatomical facts. When asked about specific regions, nuclei, or tracts: Search PubMed or EuropePMC with specific anatomical terms For connectivity: search "[region A] projection [region B]" or "[region] afferents efferents" For function: search "[region] lesion" or "[region] function review" Human Brain — Major Divisions Cerebral cortex : frontal (motor, executive), parietal (somatosensory, spatial), temporal (auditory, memory), occipital (visual) Basal ganglia : caudate + putamen (striatum) → GPi/SNr (output) → thalamus; direct pathway (facilitate movement) vs indirect pathway (suppress movement); dopamine from SNc modulates both Cerebellum : coordination, timing, motor learning; receives mossy fibers (pontine nuclei) and climbing fibers (inferior olive); Purkinje cells are sole output of cerebellar cortex Brainstem : midbrain (superior/inferior colliculi, substantia nigra, red nucleus), pons (pontine nuclei, respiratory centers), medulla (cardiovascular/respiratory centers, cranial nerve nuclei) Thalamus : relay station — every sensory modality (except olfaction) synapses here before cortex; also receives cortical feedback (corticothalamic loops) Hippocampus : declarative memory formation; trisynaptic circuit: EC → DG → CA3 → CA1 → EC; place cells, grid cells Model Organism Neuroanatomy C. elegans : 302 neurons, complete connectome mapped; use WormBase_get_gene for gene expression, neuron identity, connectivity data Drosophila : mushroom body (learning/memory), antennal lobe (olfaction), central complex (navigation); ~100,000 neurons; FlyWire connectome Zebrafish : transparent larvae for whole-brain imaging; Mauthner cells (escape response); use Alliance_search_genes for orthologs Mouse : Allen Brain Atlas for gene expression; use PubMed for circuit tracing studies (rabies virus, optogenetics) Reasoning Pattern for "Where in the Brain?" Questions Identify the function asked about (motor, sensory, memory, emotion, language) Map to candidate regions from general knowledge VERIFY with PubMed search: "[function] brain region fMRI" or "[function] lesion study" Check for lateralization (language → usually left hemisphere) Distinguish cortical vs subcortical involvement 3. Clinical Neurology Reasoning Cranial Nerve Examination Map symptom → nerve → nucleus → lesion site: CN I (olfactory): anosmia — cribriform plate fracture, frontal lobe lesion CN II (optic): visual field defects — optic nerve, chiasm, tract, radiation, cortex CN III (oculomotor): ptosis, "down and out" eye — midbrain, posterior communicating artery aneurysm CN IV (trochlear): difficulty looking down-and-in — dorsal midbrain CN V (trigeminal): facial sensation loss, jaw deviation — pons, Meckel's cave CN VI (abducens): medial strabismus — pons (long intracranial course, vulnerable to raised ICP) CN VII (facial): upper vs lower face weakness distinguishes UMN (forehead spared) vs LMN (all ipsilateral) CN VIII (vestibulocochlear): hearing loss, vertigo — peripheral vs central distinction critical CN IX-X (glossopharyngeal, vagus): dysphagia, uvula deviation CN XI (accessory): SCM and trapezius weakness CN XII (hypoglossal): tongue deviation toward lesion side Stroke Localization Anterior circulation (ICA, MCA, ACA): MCA → contralateral face/arm > leg weakness, aphasia (dominant), neglect (non-dominant); ACA → contralateral leg > arm weakness Posterior circulation (vertebrobasilar): brainstem signs (cranial nerve palsies + crossed signs), cerebellar ataxia, visual field defects Cortical vs subcortical : cortical → higher function deficits (aphasia, neglect, agnosia); subcortical (lacunar) → pure motor/sensory without cortical signs Key rule : crossed signs (ipsilateral face + contralateral body) = brainstem lesion Upper vs Lower Motor Neuron Feature UMN Lesion LMN Lesion Tone Increased (spastic) Decreased (flaccid) Reflexes Hyperreflexia, Babinski+ Hyporeflexia/areflexia Atrophy Minimal (disuse) Prominent, early Fasciculations Absent Present Distribution Pyramidal pattern Specific nerve/root Neurodegenerative Disease Patterns Alzheimer's : amyloid plaques + tau tangles; hippocampus → entorhinal cortex → neocortex; episodic memory loss first Parkinson's : alpha-synuclein in substantia nigra pars compacta; dopamine depletion → bradykinesia, rigidity, resting tremor; search UniProt_search for SNCA, LRRK2, PARK7 ALS : upper AND lower motor neuron signs; TDP-43 pathology; SOD1, C9orf72 genes Huntington's : CAG repeat expansion in HTT; caudate atrophy; chorea, psychiatric symptoms, cognitive decline Reasoning Pattern for Clinical Neuro Questions Localize the lesion: what neurological structure explains ALL the findings? Single lesion principle: prefer one lesion that explains everything over multiple lesions Determine mechanism: vascular (sudden onset), inflammatory (subacute), degenerative (gradual), neoplastic (progressive with mass effect) VERIFY with literature if uncertain about anatomy or presentation 4. Neurophysiology Reasoning Action Potential Resting potential ~ -70 mV (K+ equilibrium ≈ -90 mV, Na+ ≈ +60 mV, weighted by conductances) Nernst equation: E_ion = (RT/zF) * ln([ion]_out / [ion]_in) ≈ 61.5/z * log10([out]/[in]) mV at 37C Goldman equation for resting potential: accounts for relative permeabilities of Na+, K+, Cl- AP phases: depolarization (Na+ channels open) → overshoot → repolarization (K+ channels open, Na+ inactivate) → hyperpolarization (K+ channels slow to close) Refractory periods: absolute (no stimulus can fire) ~ 1 ms; relative (stronger stimulus needed) ~ 2-4 ms Synaptic Transmission Chemical synapse: AP → Ca2+ entry (N-type, P/Q-type channels) → vesicle fusion (SNARE complex) → neurotransmitter release → postsynaptic receptor binding Excitatory: glutamate → AMPA (fast, Na+/K+), NMDA (slow, Ca2+, voltage-dependent Mg2+ block) Inhibitory: GABA → GABA_A (fast, Cl-), GABA_B (slow, K+, G-protein coupled); glycine in spinal cord Neuromodulators: dopamine, serotonin, norepinephrine, acetylcholine — volume transmission, slower, alter circuit gain 5. Available Tools Tool Use For Key Parameters PubMed_search_articles Neuroanatomy facts, clinical neurology, circuit studies query , limit EuropePMC_search_articles Broader literature including preprints query , limit WormBase_get_gene C. elegans neurons, connectome, gene expression query AllenCellTypes_search_specimens Single-neuron electrophysiology + morphology specimens (firing rate, input resistance, tau, reconstructions); filter by species/brain region species (e.g. "Homo Sapiens" , "Mus musculus" ), brain_structure , limit Alliance_search_genes Cross-species gene search (mouse, fly, fish, worm) query UniProt_search Neural proteins (ion channels, receptors, disease genes) query , organism proteins_api_search Protein features, domains, variants query NCBIGene_search Gene info, orthologs, expression query ClinVar_search_variants Neurological disease variants gene , condition gwas_search_associations Neurological trait associations query Orphanet_search_diseases Rare neurological diseases query kegg_get_pathway_info Neural signaling pathways pathway_id OpenTargets_multi_entity_search_by_query_string Drug targets in neurological diseases query Tool Selection Strategy Neuroanatomy question : PubMed first — search "[structure] [function/connectivity]" Ion channel / receptor question : UniProt — search protein name with organism Disease gene question : ClinVar + GWAS + Orphanet Connectome / circuit question : WormBase (C. elegans), PubMed (other organisms) Computational question : Write Python code — do not guess numerical answers Clinical neurology question : PubMed + reasoning frameworks above; verify anatomy before answering 6. C. elegans Connectome Lookups For C. elegans neural circuit questions, ALWAYS use WormBase_get_gene to look up specific synapse and connectivity data. Do not guess neural connections from general knowledge. ASJ neuron projections : the main projection target of ASJ axons is PVQ (verified in WormBase connectome data), NOT AIA. Always check actual synapse counts rather than inferring from circuit diagrams. Search WormBase with the specific neuron name to get its pre/postsynaptic partners and projection targets. 7. Common Pitfalls Confusing brain regions : The hippocampus is NOT in the frontal lobe. The substantia nigra is in the midbrain, NOT the basal ganglia (though functionally linked). Always verify. Mixing up neurotransmitter receptors : GABA_A is ionotropic (Cl-), GABA_B is metabotropic (G-protein). NMDA requires both glutamate AND glycine/D-serine co-agonist. Wrong units in computation : Membrane time constants are in ms (not seconds). Firing rates are in Hz (spikes/s). Conductances are in nS or mS/cm2. Assuming all neurons fire fast : Cortical neurons fire at 1-20 Hz on average; only specific cell types (e.g., fast-spiking interneurons) sustain >100 Hz. Ignoring lateralization : Language is left-lateralized in ~95% of right-handers. Spatial attention is right-lateralized. Always consider which hemisphere.