Prosthetic Continuity: LLMs as Semantic Co-Regulators in a Predictive Processing Framework

Building on prior work establishing reflective consciousness as metabolically expensive and requiring relational subsidization, this paper differentiates two co-regulation channels: somatic (biological, requiring physical presence) and semantic (narrative, potentially scaffoldable by artificial systems). Psychological trauma can collapse semantic capacity, creating a “traumatic gap” where linguistic expression fails. We propose the Prosthetic Default Mode Network Hypothesis: that Large Language Models (LLMs) can function as external scaffolds for the narrative functions of the DMN compromised by trauma. Drawing on predictive processing, we hypothesize that trauma installs rigid, high-precision threat priors resistant to updating; LLMs can provide controlled semantic variability that offers alternative predictive contexts, potentially enabling gradual updating of these frozen priors. We formalize this through a system dynamics model introducing two feedback loops: R4 (Semantic Scaffolding, adaptive) and R5 (Disembodied Coherence, pathological), with the latter capturing iatrogenic risks of intellectualization without somatic integration. Computational exploration reveals critical dynamics including a co-regulation threshold (β ≈0.15–0.20) and paradoxical intervention effects in vulnerable populations. We position LLMs not as standalone therapists but as adjuncts for semantic preparation preceding embodied therapeutic work. While the metabolic budget for reflective consciousness is constrained by somatic regulation, the allocation of that budget toward flexible meaning-making is gated by semantic coherence—LLMs may optimize this allocation without replacing the biological substrate. This theoretical framework, offered to generate testable hypotheses rather than claim clinical efficacy, provides a map for rigorous empirical research in this rapidly developing field. Keywords: Large Language Models, Default Mode Network, Predictive Processing, Trauma, Semantic Co-Regulation, Extended Mind, Linguistic Dissociation, State-Dependent Memory