Cervico-suboccipital sensorimotor convergence as an upstream autonomic pathway in bilateral rhythmic stimulation.

Rhythmic bilateral stimulation is a defining procedural feature of Eye Movement Desensitization and Reprocessing (EMDR), yet its physiological significance remains unresolved. Existing accounts have mainly emphasized rapid cognitive and attentional mechanisms during traumatic memory processing, including working-memory taxation, dual attention, and reductions in memory vividness and emotionality. This Hypothesis and Theory article develops a complementary upstream physiological model that separates acute cognitive-attentional effects from proximal sensorimotor-autonomic coupling and slower downstream neuroimmune hypotheses. It proposes that bilateral or spatially organized rhythmic stimulation generates modality-specific ocular, vestibulo-cervical, proprioceptive, autonomic, and cervico-suboccipital signatures. These signatures may contribute to rapid bodily-autonomic effects, such as orienting responses and parasympathetic shifts, through brainstem integration and vagal efferent output, without requiring direct vagal afferent stimulation from the stimulated site. Across repeated stimulation, the resulting autonomic-vascular state is proposed to interface with cerebrospinal fluid dynamics, meningeal lymphatic exchange, deep cervical lymph node drainage, and glial or regulatory immune mechanisms, including the regulatory T-cell-centered pathway proposed previously. Mastoid and peri-auricular stimulation are discussed as a potentially shorter upper-cervical entry point to this sensorimotor-autonomic pathway because their anatomical position is suited to engage local somatosensory, vestibular-adjacent, cervical proprioceptive, and cervico-suboccipital systems. The model is presented as a testable physiological framework that requires direct experimental validation. It generates predictions for future studies combining standardized rhythmic stimulation protocols with ocular, cervical, autonomic, cerebrospinal fluid, meningeal lymphatic, and neuroimmune measures.