Neuroreflex Development and the Vestibular System

Primitive and postural reflexes play foundational roles in the development and maturation of the vestibular system, which is responsible for balance, spatial orientation, and coordinating movement with visual input. These reflexes help "train" the nervous system in early life to integrate sensory and motor information, laying the groundwork for more complex voluntary movement and stability.

Primitive Reflexes and the Vestibular System

Primitive reflexes are automatic, stereotyped movements directed from the brainstem that appear in infancy and typically fade as the cortex matures. Reflexes such as the Moro, TLR and ATNR activate the vestibular system through changes in head position and movement. Proprioception and the maturation of primitive reflexes help a baby learn where their body is in space, which is vital for developing vestibular-motor integration. Vestibular-motor integration is the process by which the vestibular system (which senses head movement, balance, and spatial orientation) works together with the motor system (which controls movement) to produce coordinated, stable, and purposeful physical actions. In addition, Primitive reflexes help coordinate movements of the head, eyes, and limbs, practicing basic patterns that will later be refined with help from the vestibular system. As primitive reflexes “fade” or integrate, our postural reflexes emerge, partially driven by increased vestibular processing and motor control. 

Postural Reflexes and the Vestibular System

Postural reflexes begin to emerge between 2-4 months of age. They support head and body alignment and develop in tandem with voluntary motor control. The Headrighting Reflex helps develop the vestibular-ocular reflex by ensuring the head is properly aligned and supports a stable gaze during movement or at rest like for reading. Righting reflexes both depend on the vestibular system for development but also further strengthen and develop it. Postural reflexes are critical for crawling, standing, and walking. These activities strong stimulate and further develop the vestibular system. 

The Impact of an Underdeveloped Vestibular System

When a child’s vestibular system is underdeveloped, it can have widespread implications for further development of balance and coordination, visual-motor skills, poor spatial awareness, poor visual tracking and gaze stability, clumsiness or frequent falls, may appear hyperactive, and/or chronic anxiety. A child may have trouble with attention and sitting still due to poor postural control.

Poor Vestibular Function and the Autonomic Nervous System (Moro, Fear Paralysis)

Poor vestibular functioning can trigger the sympathetic state of the autonomic nervous system (ANS) by creating a sense of instability, disorientation, and threat to safety, which the brain interprets as stressful or dangerous. This perceived threat activates the sympathetic nervous system—the “fight or flight” response—even in the absence of real danger.

Pathway	Explanation
Perceived Danger or Instability	The brain interprets poor vestibular input as a potential fall or threat to safety—even if there's no immediate risk.
Limbic System Activation	The amygdala and other emotional centers react to this instability, triggering fear, anxiety, or stress.
Hypothalamic-Pituitary-Adrenal (HPA) Axis	Stress signals activate the HPA axis, which releases stress hormones like cortisol.
Sympathetic Nervous System (SNS)	The body enters a heightened state of arousal: increased heart rate, shallow breathing, muscle tension, hypervigilance.

(article written with the assistance of generative AI).