The interoceptive communication model (ICM 2.0): a state-dependent neurophysiological framework for behavioral and cognitive accessibility.

Behavioral, emotional, and cognitive variability across contexts remains insufficiently explained by models that rely on environmental contingencies, cognitive processes, or static trait-based constructs. Individuals may exhibit marked fluctuations in executive functioning, emotional regulation, learning access, behavioral flexibility, and adaptive responses despite retaining knowledge, insight, or previously acquired skills. These patterns are frequently reported in trauma-related conditions, chronic stress, autism spectrum disorder, psychiatric disorders, rehabilitation, and educational settings. ICM 2.0 proposes that these fluctuations reflect dynamic changes in physiological accessibility rather than permanent changes in an individual's underlying capacities. This study operationally defines accessibility as the probability that a previously demonstrated capacity can be recruited under specified physiological, contextual, and task conditions, explicitly distinguishing it from capacity, motivation, engagement, arousal, and performance outcomes. Accessibility is conceptualized as a latent state-dependent construct inferred from converging physiological, behavioral, subjective, and, when available, neural indicators. The Interoceptive Communication Model (ICM 2.0) is proposed as a state-dependent neurophysiological framework that organizes interactions among autonomic regulation, interoceptive processing, affective signaling, sensory load, endocrine activity, immune signaling, environmental context, and higher-order regulatory modulation. The model introduces two broad processing tendencies. Route 1 reflects a limbic-autonomic survival-oriented pattern associated with restricted adaptive accessibility. Meanwhile, Route 2 reflects an insular-prefrontal regulatory pattern associated with expanded adaptive accessibility. These terms are explicitly heuristic and are not intended as anatomical or localized neural pathways. ICM 2.0 generates testable predictions: physiological dysregulation is expected to reduce access to adaptive capacities independently of prior skill acquisition, and regulation-focused interventions are expected to increase accessibility before measurable behavioral improvement from skill training alone. The framework is differentiated from Polyvagal Theory, predictive processing, active inference, and neurovisceral integration. It also specifies measurement strategies, biological mechanisms, and empirical testability criteria.