Primitive Reflexes and Their Role in Nervous System Development

 Primitive reflexes (PRs) are foundational components of the human nervous system, serving as essential building blocks for complex motor and cognitive functions. These automatic, involuntary movements are present at birth and typically integrate as the child matures, usually by the age of two. Controlled by cranial nerves in the brainstem—a primitive part of the brain—these reflexes maintain a balance between the parasympathetic and sympathetic nervous systems, supporting motor movement, decision-making, and emotional regulation. When these reflexes remain reactive or reemerge later in life, they disrupt vagal nerve signals, leaving the body in a heightened state of arousal, and flooding the brain with stress hormones along the HPA axis.

Fear Paralysis Reflex (FPR) and Startle Reflex

The Fear Paralysis Reflex (FPR) is one of the earliest survival mechanisms to develop in utero, typically emerging around 5-8 weeks gestation. It serves as an instinctual response to perceived threats, causing the fetus to momentarily freeze, characterized by a withdrawal of movement and a tensing of the body. This reflex potentially prepares the fetus for more complex survival responses, such as the fight-or-flight mechanism. Ideally, the FPR should be integrated by birth or within the first two months of life. Proper integration of this reflex is crucial for normal neurological development, as failure to integrate the FPR can result in heightened anxiety, exaggerated stress responses, and difficulties with emotional regulation later in life. When unintegrated, the reflex may lead to chronic patterns of fear and withdrawal, manifesting in symptoms such as muscle tension, hypersensitivity, and difficulties in coping with stress.

Moro Reflex

 The Moro Reflex, distinct from the Startle Reflex, is a higher-order primitive reflex that appears at birth and is typically integrated by 4-6 months of age. This reflex is triggered in response to a sudden loss of support, such as when the infant feels as if they are falling. Upon activation, the infant abruptly extends their arms and legs, opens their hands, then brings their arms together as if to grasp something, often accompanied by crying. The Moro Reflex is crucial for early survival, helping the infant respond to sudden changes in their environment. This reflex engages multiple cranial nerves, including the vestibulocochlear nerve (CN VIII) for processing balance-related stimuli and the accessory nerve (CN XI) for coordinating the motor response of arm movement. Proper integration of the Moro Reflex is essential for healthy neurological development.

Head Righting Reflex

The Head Righting Reflex appears around 2-3 months of age and is essential for helping an infant maintain a proper head position in response to changes in body orientation. When the infant is tilted to one side, the head will automatically move to remain upright, ensuring that the eyes stay level with the horizon. This reflex plays a key role in developing balance, coordination, and the ability to move independently. By ensuring that the head stays aligned with the body's midline, the Head Righting Reflex supports the development of other motor skills such as sitting, crawling, and walking. Proper integration of this reflex, typically by 6 months of age, is crucial for the progression of motor development and the ability to navigate the environment with stability and control.

Palmar Grasp Reflex

 The Palmar Grasp Reflex is a primitive reflex that appears at birth and typically integrates by 5-6 months of age. This reflex is triggered when an object is placed in the infant’s hand, causing the infant to close their fingers around it in a tight grasp. This automatic response is crucial for the early development of hand-eye coordination and lays the foundation for voluntary grasping and fine motor skills that will emerge later in infancy.

Planer Grasp and Step Reflexes

The Plantar Grasp Reflex appears at birth and is typically integrated by 9-12 months of age. When the sole of the infant's foot is touched or pressure is applied to the ball of the foot, the toes will reflexively curl downwards in a grasping motion. This reflex plays an important role in developing the muscles and coordination needed for standing, balancing, and eventually walking. The integration of this reflex is crucial for the progression of motor skills, allowing the infant to develop the proper foot and toe movements necessary for stable and effective locomotion.

Spinal Galant Reflex

The Spinal Galant Reflex is a primitive reflex that appears at birth and is typically integrated by 3-9 months of age. This reflex is triggered when the skin along the side of the infant's back is stroked, causing the infant to curve their body towards the stimulated side. The Spinal Galant Reflex plays a crucial role in the development of coordination and flexibility in the trunk, which is important for crawling and other early movements. Additionally, this reflex is thought to assist in the birthing process by helping the baby to navigate through the birth canal.

Asymmetrical Tonic Neck Reflex (ATNR)

The Asymmetrical Tonic Neck Reflex (ATNR) is a primitive reflex that appears at birth and is typically integrated by 6 months of age. This reflex is triggered when the infant’s head is turned to one side, causing the arm and leg on that side to extend, while the opposite arm and leg flex. The ATNR supports the development of hand-eye coordination and motor skills by encouraging the infant to explore their environment and helping to establish neural connections necessary for coordinated movement and awareness of the body’s left and right sides.

Symmetrical Tonic Neck Reflex (STNR)

The Symmetrical Tonic Neck Reflex (STNR) typically appears around 6-9 months of age and is usually integrated by 9-11 months of age. This reflex is activated when the infant’s head is flexed or extended, causing the arms and legs to respond in a coordinated manner—when the head is flexed forward, the arms bend, and the legs straighten; when the head is extended backward, the arms straighten, and the legs bend. The STNR plays a crucial role in helping the baby learn to crawl by enabling the separation of upper and lower body movements. This reflex is essential for transitioning from lying to sitting and for the development of crawling, which is important for hand-eye coordination and overall motor development.

Tonic Labyrinthine Reflex (TLR)

The Tonic Labyrinthine Reflex (TLR) is a primitive reflex that appears at birth and is typically integrated by 3.5 years of age. This reflex is activated by changes in the position of the head relative to gravity, such as when the head tilts forward or backward. The TLR plays a significant role in helping the infant develop muscle tone, balance, and coordination, as it influences the way muscles respond to the position of the head. This reflex is essential for the development of postural control and foundational movement patterns that support activities like rolling, crawling, and eventually walking.

Core Tendon Guard Reflex and Achilles Guard

 The Core Tendon Guard (CTG) Reflex appears in early infancy and is typically integrated by 1 year of age. This reflex is triggered by a perceived threat or sudden movement, causing an automatic contraction of the core muscles to provide stability and protect the spine and internal organs. The CTG Reflex plays a vital role in the development of core strength and postural control, serving as the body's natural defense mechanism to prevent injury. It is crucial during the early stages of development, as it helps the infant establish a stable base for movement and supports the alignment and protection of the spine as they begin to explore their environment.

Cranial Nerves and Their Influence on Development

 The cranial nerves are the primary neural pathways that emerge directly from the brain, playing essential roles in sensory perception, motor control, and autonomic regulation. There are twelve pairs of cranial nerves, each responsible for specific functions, ranging from the senses of smell, vision, and hearing to the control of muscles in the face, eyes, and throat. These nerves are crucial for communication between the brain and various parts of the head, neck, and torso, as well as for regulating vital bodily functions such as heart rate and digestion.

Primitive Reflexes, Sinew Channels, and Eight Extraordinary Vessels

 Primitive Reflexes, Sinew Channels, and Eight Extraordinary Vessels

Table of Refelxes and Their Associated Information

 

Table of Reflexes and Their Associated Information:

Reflex	Appears	Integrates	Muscles Involved	8 Extra Meridians	Myelin	Higher FXN	Acu Points	Fascial Lines	Cranial Nerves
Fear Paralysis Reflex (FPR)	In utero (5-8 weeks)	Birth to 2 months	Deep abdominal muscles, Diaphragm, Psoas, Adductor	Ren	No	No	REN17 (Shanzhong), REN12 (Zhongwan), SP21 (Dabao), SP2 (Dadu), LU1 (Zhongfu), LU2 (Yunmen), SP20 (Zhourong)	Superficial Front Line (SFL)	Vagus nerve (CN X)
Startle Reflex	Birth	2-4 months	Neck muscles, Upper trapezius, Sternocleidomastoid, Diaphragm	Ren, Du	No	No	DU20 (Baihui), REN12 (Zhongwan), GB21 (Jianjing)	Superficial Back Line (SBL)	Accessory nerve (CN XI), Vagus nerve (CN X)
Moro Reflex	Birth	4-6 months	Shoulder girdle muscles, Upper trapezius, Latissimus dorsi, Neck extensors	Chong, Dai	No	No	REN12 (Zhongwan), REN14 (Juque), GB25 (Jingmen), LV13 (Zhangmen)	Superficial Back Line (SBL)	Accessory nerve (CN XI), Vagus nerve (CN X)
Rooting Reflex	Birth	3-4 months	Facial muscles, Neck muscles, Tongue muscles, Sternocleidomastoid	Ren, Du, Yang Qiao	No	No	REN24 (Chengjiang), ST4 (Dicang), DU26 (Renzhong)	Deep Front Line (DFL)	Trigeminal nerve (CN V), Facial nerve (CN VII), Hypoglossal nerve (CN XII)
Head Righting Reflex	2-3 months	6 months	Neck muscles, Trapezius, Sternocleidomastoid	Ren, Du, Yang Qiao	Yes	Yes	DU20 (Baihui), GB20 (Fengchi), REN12 (Zhongwan), ST8 (Touwei)	Deep Front Line (DFL) |	Accessory nerve (CN XI), Vestibulocochlear nerve (CN VIII) |
Palmar Grasp Reflex	Birth	5-6 months	Flexor muscles of the forearm, Intrinsic muscles of the hand, Biceps, Brachioradialis		No	No	LI4 (Hegu), PC8 (Laogong), HT8 (Shaofu)	Arm Lines	Median nerve (C5-T1) (Peripheral nerve)
Plantar Grasp Reflex	Birth	9-12 months	Flexor muscles of the foot, Intrinsic foot muscles, Calf muscles, Tibialis anterior	Yang Qiao	No	No	KD1 (Yongquan), LV3 (Taichong), BL60 (Kunlun)	Superficial Back Line (SBL)	Tibial nerve (L4-S3) (Peripheral nerve)
Spinal Galant Reflex	Birth	3-9 months	Spinal muscles, Hip muscles, Abdominals, Gluteal muscles	Dai	No	No	BL23 (Shenshu), GB30 (Huantiao), BL25 (Dachangshu)	Lateral Line (LL)	Accessory nerve (CN XI)
Asymmetrical Tonic Neck Reflex (ATNR)	Birth	6 months	Neck rotators, Shoulder girdle muscles, Abdominals, Hip flexors	Dai, Yang Wei	Yes	Yes	SI3 (Houxi), LI15 (Jianyu), GB20 (Fengchi)	Spiral Line (SL)	Accessory nerve (CN XI)
Tonic Labyrinthine Reflex (TLR)	Birth	3.5 years	Neck flexors and extensors, Long strap muscles in the back, Abdominals, Gluteal muscles	Ren, Du	Yes	Yes	BL10 (Tianzhu), DU20 (Baihui), CV6 (Qihai)	Superficial Back Line (SBL)	Accessory nerve (CN XI), Vagus nerve (CN X)
Symmetrical Tonic Neck Reflex (STNR)	6-9 months	9-11 months	Neck flexors and extensors, Shoulder girdle muscles, Abdominals, Quadriceps	Du, Yang Wei	Yes	Yes	DU14 (Dazhui), GB21 (Jianjing), ST36 (Zusanli)	Deep Front Line (DFL)	Accessory nerve (CN XI)
Core Tendon Guard Reflex	Early infancy	1 year	Core muscles, Diaphragm, Hip flexors, Lower back muscles	Ren, Chong	No	No	CV4 (Guanyuan), ST25 (Tianshu), SP15 (Daheng)	Deep Front Line (DFL)	Vagus nerve (CN X)
Achilles Reflex	Birth	2 years	Calf muscles, Achilles tendon, Tibialis anterior	Yang Qiao	No	No	BL60 (Kunlun), KD3 (Taixi), GB40 (Qiuxu)	Superficial Back Line (SBL)	Tibial nerve (L4-S3) (Peripheral nerve)