diff --git a/elements/neuron/appunti/2026-06-19-logic-principles-of-the-expression.md b/elements/neuron/appunti/2026-06-19-logic-principles-of-the-expression.md new file mode 100644 index 0000000..e69de29 diff --git a/elements/neuron/appunti/old/2026-06-11-general-guidelines-for-G-expression.md b/elements/neuron/appunti/old/2026-06-11-general-guidelines-for-G-expression.md new file mode 100644 index 0000000..163cf6b --- /dev/null +++ b/elements/neuron/appunti/old/2026-06-11-general-guidelines-for-G-expression.md @@ -0,0 +1,157 @@ +--- +include_toc: true +--- + +# Logic principles + +Here are the logic principles that have guided the construction, organized from the most fundamental to the most specific. + +--- + +## I. Principles of Resource and Conservation + +**Nothing is free.** Every behavior consumes a budget. There is no operation in the system that does not draw down some resource. This is not a constraint added on top of the logic — it is the foundation of the logic. Selectivity, competition, and forgetting all emerge from the fact that resources are finite. + +**Resources are redistributed, not created.** The total resource pool is bounded by an external ceiling (the vascular glucose supply). Within that ceiling, the system moves resources around — from one synapse to another, from structure back to pool when structures are dismantled. No internal process can manufacture new capacity; it can only reallocate existing capacity. Learning is therefore always at the expense of something else. + +**Every economy has a single capped root.** Each resource type traces back to one producer with a hard output ceiling — the astrocyte cell body for synaptic energy, the soma for neuronal structural material. Everything downstream competes for shares of that capped production. The ceiling is the ultimate arbiter of how much the system can do. + +**Conservation makes one synapse's gain another's loss.** Because resources are shared and finite, potentiation at one site necessarily reduces what is available elsewhere. This coupling is not designed — it is the automatic consequence of drawing from a common pool. + +--- + +## II. Principles of Time and Scope + +**Behavior and structural change occupy separate scopes.** Fast behavior happens in DAY; permanent structural change happens in NIGHT. This separation prevents transient activity from directly rewriting architecture — every noise spike would otherwise remodel the system. The scope boundary is the mechanism that makes the system both responsive and stable. + +**DAY accumulates evidence; NIGHT acts on it.** No decision about permanent change is made during DAY. DAY only gathers traces. NIGHT reads the accumulated evidence and commits. The system never commits in the moment — it always defers commitment to a consolidation phase that operates on aggregated evidence. + +**Every quantity has a characteristic timescale, and timescale is meaning.** Fast traces decay in milliseconds, tags in hours, structures over days. The decay constant of a variable is not a parameter — it is what the variable means. A variable that decays fast is a momentary signal; one that decays slowly is a commitment. Putting two different timescales in one variable destroys both meanings. + +**Time windows are enforced by chemistry, not by clocks.** The system never checks a timer. Coincidence windows emerge from the competition between accumulation and decay. A signal must arrive while a trace is still elevated. The window opens when the trace crosses a threshold and closes when it decays below it. Timing is a consequence of dynamics, not an explicit rule. + +--- + +## III. Principles of Capacity and Occupancy + +**NIGHT builds containers; DAY fills them.** Structural variables are capacities — ceilings on what behavior can achieve. NIGHT changes the ceiling. DAY operates within it. The two never do each other's job: NIGHT never places a receptor, DAY never builds a slot. + +**Short-term change is occupancy; long-term change is capacity.** Filling a container more or less is fast and reversible. Changing the size of the container is slow and persistent. The same physical quantity — receptor count, vesicle count — has a fast component (how full) and a slow component (how big), and these are governed by entirely different processes. + +**Structure is simultaneously memory and prior.** The architecture left by the last NIGHT is both a record of past significant experience and a bias on how the next DAY will respond. A potentiated synapse is more likely to respond strongly and therefore more likely to be potentiated again. Structure encodes what mattered and predicts what will matter. + +--- + +## IV. Principles of Locality and Non-Locality + +**Short-term change is local; long-term change is non-local.** A component can transiently potentiate from its own activity alone. But to permanently change, it requires validation from beyond itself — from other compartments, from the soma, from the organism. Cheap reversible change is autonomous; expensive permanent change requires external authorization. + +**Permanent change requires coincidence across spatial scales.** A tag forms only when a local eligibility signal meets one or more non-local confirmation signals. The number of required coincidences reflects where the component sits in the hierarchy — the postsynapse, as the primary memory locus, requires the most. Each scale confirms something the previous scale cannot know about itself. + +**The whole validates the part; the part cannot validate itself.** A synapse cannot know whether its activity was behaviorally significant — that information exists only at the organism level. The neuromodulatory broadcast carries organism-level significance down to the synapse. This is why the system is open: the highest validation comes from outside any component that is being modified. + +--- + +## V. Principles of Selection and Asymmetry + +**Potentiation is the active drive; depotentiation is its shadow.** The entire machinery is oriented toward strengthening what is significant. There is no symmetric machinery for weakening. Weakening happens to whatever potentiation did not select, as a consequence of the resources potentiation consumed. The system is built to learn, and forgetting is the cost of learning. + +**Depression is never explicit — it is what happens when potentiation does not.** No signal says "weaken this." Structures decay continuously and are held up only by maintenance resources. When potentiation consumes those resources, unmaintained structures drift down. Depression is the absence of maintenance, not the presence of a depression signal. + +**Selection requires winning on multiple independent criteria.** To be permanently strengthened, a synapse must be both active enough to be fueled and significant enough to be validated. These are independent gates. Activity without significance is not saved; significance without sustainable activity cannot be maintained. The conjunction is what filters for genuinely valuable connections. + +**The system finds equilibrium through the residual of its own imperfection.** Where alignment or balance is achieved, the very success removes the signal that drove it, allowing slow drift back toward imbalance, which regenerates the driving signal. The system hovers near optimum, continuously corrected by the small errors its own imperfect state produces. Equilibrium is dynamic, maintained by residual error, never static. + +--- + +## VI. Principles of Bottom-Up Emergence + +**Complex temporal behavior emerges from local reactive traces, not from explicit computation.** The soma aligns with its input rhythm without representing the rhythm. It simply leaves a trace when an input arrives during refractoriness and lets that trace speed future recovery. Prediction, anticipation, and rhythm-tracking emerge from purely local, reactive deposits — never from a model of the future. + +**The system never represents what it is becoming tuned to.** A potentiated synapse does not contain a representation of the pattern it responds to — it is physically biased toward that pattern. The tuning is the structure, not a description of the structure. Prediction is implicit physical bias, not explicit expectation. + +**Global organization arises from local competition.** Sparsification, normalization, and winner-take-more dynamics are nowhere computed centrally. They emerge automatically from many local units drawing from shared pools. The astrocyte does not decide which synapses to fuel — the synapses' own demands, competing for capped production, produce the allocation. + +--- + +## VII. Principles of Coupling and Self-Reinforcement + +**Couplings create trajectories, not just states.** Some variables, once moved in a direction, make further movement in that direction easier — the astrosynapse wrapping tighter after potentiation, which makes future potentiation easier. These self-reinforcing couplings mean the system has momentum: it does not just occupy states, it follows trajectories, deepening whatever direction it has begun. + +**The same signal can serve opposite functions through different receptors.** Glutamate spillover brakes the presynapse while exciting the astrocyte — one ligand, two receptor types, opposite cascades, simultaneous opposite effects. Function is determined by the receiver, not the signal. This lets one event coordinate multiple responses without any coordinating mechanism. + +**Energy availability is itself a selective pressure, parallel to validation.** Beyond the explicit activity-and-reward gating, the simple availability of energy continuously selects which synapses can participate. A synapse that cannot be fueled cannot generate the activity that would let it be tagged. Metabolism silently shapes what can be learned, in parallel with and independent of the explicit plasticity machinery. + +--- + +## VIII. Principles of Openness and Boundedness + +**The system is finite and open, not infinite and closed.** It has bounded components and a bounded state space, and it receives inputs it cannot generate from within — sensory drive, neuromodulatory validation, metabolic supply. Because it is finite, its self-modification does not generate infinite regress. Because it is open, its highest validation comes from outside itself. + +**The fixed points are made explicit, not hidden.** The parameters the system cannot modify from within — thresholds, the vascular ceiling, the neuromodulatory signals — are declared as fixed. These are the system's boundary with what it did not set and cannot inspect. Making them explicit is the honest acknowledgment that every self-modifying system operates within constraints it did not choose. + +**Validation comes from embedding, not from internal consistency.** The system does not certify its own changes as correct. Whether a structural change was good is answered by the organism's subsequent experience in the world, fed back through the neuromodulatory system. Correctness is determined by the coupling between system and environment, not by any internal criterion. This is what it means for the fixed point to lie outside the system: the system acts, the world responds, and the response — not any internal check — determines what was worth keeping. + +--- +--- +--- + +# Complete set of general guidelines (old) + +## DAY — Behavior + +**Behavior is determined by structure modulated by NIGHT.** +Every DAY behavior operates within the ceiling set by the previous NIGHT's structural commit. The neuron does not decide how sensitive its spines are, how large its active zones are, or how tightly its astrosynapse wraps the cleft — it simply operates within whatever architecture NIGHT left behind. Structure is the memory of past validated experience, and it silently shapes every moment of current processing. + +**Behavior has an energy cost.** +Every behavior draws from the local budget. No behavior is free. The budget has a hard ceiling set by the vascular glucose supply through the astrocyte, and by the soma's own mitochondrial capacity. When the budget is exhausted, behavior is suppressed regardless of the input — the bouton goes silent, the spine cannot reset, the branch cannot propagate the bAP. Energy scarcity is not a failure mode — it is a regulatory mechanism that prevents runaway activity from destabilizing the system. + +**Behavior has a material cost.** +Fast behaviors consume biological materials — D-serine precursors, vesicle membrane proteins, actin monomers for transient spine changes. These are distinct from energy: a behavior can be energetically affordable but materially limited. D-serine release depletes the astrocyte's serine pool. Sustained vesicle release depletes the readily-releasable pool faster than it can be refilled. Material costs impose a second independent constraint on behavior that energy alone does not capture. + +**Behavior leaves traces.** +Every behavior deposits a graded, decaying record of its occurrence in the local fast trace variable. The trace is not a passive record — it actively biases the next behavior in the same context. Residual calcium in the bouton makes the next release more probable. Calcium in the spine encodes the instruction for future structural change. The trace is the system's short-term memory of what just happened, and it decays automatically so that only sustained or repeated behaviors accumulate enough trace to reach the tagging threshold. + +**Behavior happens in a specialized fashion determined by structure modulated by NIGHT.** +The form of the behavior — not just its ceiling but its quality — is shaped by structure. A bouton with high pre_structure has tightly clustered calcium channels beneath its docking slots, making each AP more reliably coupled to vesicle fusion. A spine with high post_structure has more anchoring slots, making each glutamate pulse more faithfully converted into AMPA current. The astrosynapse with high astro_structure delivers D-serine tonically, keeping the NMDA gate chronically primed. Structure does not just set the maximum — it shapes the transfer function between input and output at every moment. + +**Behavior happens in a time window determined by accumulation and elimination of traces.** +The eligibility window for tagging is not externally imposed — it emerges from the decay dynamics of the fast trace. A bouton is taggable only while its residual calcium is still elevated. A spine is in its Hebbian anticipation window only while its NMDA calcium is still above the tagging threshold. The window opens when the fast trace crosses the eligibility threshold and closes when it decays below it. Dopamine or the bAP must arrive within this window or find nothing to validate. Timing is enforced by chemistry, not by a clock. + +**Behavior happens in a context determined by local and global circumstances.** +Local context is the current state of the compartment itself — whether an AP just arrived, whether the membrane is depolarized, whether the RRP has content. Global context is the state of the organism — whether dopamine is elevated, whether norepinephrine is driving arousal, whether acetylcholine is signaling attention. Neither alone determines behavior. The local context determines what the compartment can do. The global context determines whether what it does gets validated. Both must align for a behavior to leave a lasting trace. + +--- + +## NIGHT — Structural Rewriting + +**Based on traces from DAY there is competition to restructure.** +The NIGHT scope is not passive recovery — it is an active competition for finite structural resources. Tags accumulated during DAY represent the claims that different synapses are making on the shared material and energy pools. Tagged synapses draw first, in proportion to their tag magnitude. The strongest tags — those that accumulated the most coincident local activity and global validation — draw the most resources and achieve the largest structural expansion. Weaker tags draw proportionally less. The competition is not adjudicated by any central mechanism — it emerges automatically from the shared pool dynamics. + +**What is not potentiated decays for lack of resources.** +After potentiation has drawn its share, what remains is distributed as maintenance to all synapses. Structural maintenance requires a continuous material and energy allocation just to resist the baseline decay of molecular components. When the maintenance allocation falls below the decay rate — because potentiation has consumed too much — untagged synapses drift toward lower structural states. They are not told to weaken. They simply do not receive enough to stay where they are. Depotentiation is the shadow of potentiation, enforced by conservation of resources rather than by an active depression signal. + +--- + +## Additional General Points + +**The system has one primary drive and one emergent consequence.** +The entire machinery — fast traces, possible tagging, tag stabilization, NIGHT commits — is oriented toward potentiation. There is no symmetric machinery oriented toward depression. Depression is what happens to everything that the potentiation machinery did not select. This asymmetry is not accidental — it reflects the organism's fundamental orientation toward learning from significant experience, with forgetting as the natural cost of that selectivity. + +**Validation requires signals from progressively larger spatial scales.** +A behavior at the synapse leaves a local fast trace. The fast trace creates local eligibility. Eligibility alone is not sufficient — the bAP from the soma must confirm coincidence at the spine level. The soma's own firing must coincide with nuclear calcium for the gene expression mandate. And the organism's dopamine broadcast must coincide with local eligibility at every level for the tag to stabilize. Each spatial scale adds a confirmation that the previous scale cannot provide for itself. The synapse cannot know whether the soma fired. The soma cannot know whether the organism's outcome was rewarding. Both are required. Neither is redundant. + +**The system integrates across time through a hierarchy of decay timescales.** +The fast trace decays in milliseconds to seconds. Possible tagging decays in seconds to minutes. The tag decays in hours. The structural variable decays over days to weeks unless maintained. Each timescale feeds the next: a single spike leaves a trace that can accumulate into possible tagging if spikes keep arriving, which can accumulate into a stable tag if dopamine validates the pattern, which can accumulate into structural change if NIGHT commits are fulfilled. The system does not decide at any single moment what to remember — it integrates continuously across all timescales simultaneously. + +**The system is conservative — resources are redistributed, not created.** +Every structural gain at one synapse is paid for by material and energy drawn from pools that all synapses share. LTD at one synapse returns material to those pools, partially funding LTP at another. The total structural capacity of the system is bounded above by the vascular glucose supply and the soma's protein synthesis ceiling. No activity can increase those ceilings — only sleep-driven CREB expression and vascular adaptation can. Within those ceilings, the system continuously redistributes its fixed resources toward whatever the organism has most recently found significant. + +**Structure is both the memory and the prior.** +The structural variables written in each NIGHT become the starting conditions for the next DAY. A potentiated synapse enters the next DAY with a larger active zone, more receptors, tighter astrosynaptic wrapping — making it more likely to respond strongly to the same pattern and more likely to reach the tagging threshold again. A depotentiated synapse enters the next DAY with reduced capacity, making it less likely to respond and less likely to be tagged. Structure is not just a record of past experience — it is a prediction about what patterns are likely to matter in the future, continuously updated by what the organism actually encounters. This is the system's implementation of a prior: a bias toward re-experiencing what has proven significant, encoded in the physical architecture of the synapse itself. + +**The astrosynapse is the gain control of the entire system.** +Unlike pre and post, whose structural variables set a ceiling on occupancy, astro_structure reshapes the input itself — controlling how much glutamate reaches effective concentration and whether the NMDA gate is chronically open or chronically closed. This makes the astrosynapse the only component whose structural change directly modifies the operating point of the other two components rather than just their range. And because its structural variable is self-reinforcing in both directions, it amplifies whatever trajectory the synapse is already on — making potentiated synapses progressively easier to potentiate and depressed synapses progressively harder to rescue. The astrosynapse is not just a third component of the synapse — it is the component that determines whether the synapse as a whole is in a learning-permissive or learning-resistant state. + +**The organism's rest period is the execution window for structural memory.** +The DAY scope fills the system with evidence — traces, tags, eligibility records — but commits nothing permanently. The NIGHT scope executes on that evidence — writing structure, replenishing budgets, clearing traces. A day without sleep would leave the tags decaying without being committed and the structural decay proceeding without being compensated. The system is architecturally dependent on the alternation between DAY and NIGHT: neither scope alone can accomplish what both together achieve. DAY without NIGHT produces learning that cannot consolidate. NIGHT without DAY produces structural replenishment without new content to consolidate.