Connectivity Maintenance Cost II: A Thermodynamic Reconstruction from a Single Primitive

Abstract

Functions are partitioned by duty cycle. A function whose state cannot be reconstructed from instantaneous sensory input must be maintained continuously and is limited by instantaneous flux; a function that can be recomputed on demand may defer consumption and is limited by integrated supply. Because the systemic fuel-reserve cascade — astrocytic glycogen through to ketogenesis — operates over hours to weeks, it defends the integral of supply but not the instant. Continuously maintained functions are therefore protected only by local delivery capacity, which accounts for the dissociation between prolonged starvation, which does not produce dementia, and delivery pathology, which does. The model reproduces the observed insensitivity of the global budget to task load without additional assumption, derives the scaling of maintenance cost with connectivity from the thermodynamics of information held against decay, and yields an ordinal prediction: under restriction, functions should fail in an order fixed in advance by quantities measurable in the intact brain rather than inferred retrospectively from the failure itself. This inverts the direction of inference of the antecedent preprint (doi:10.5281/zenodo.21544688), in which cost was inferred from the observed failure sequence. Free parameters, domain exclusions, and untested predictions are stated explicitly. The empirical estimation described in Section III.C is pre-specified but has not yet been performed.