Primitive reflexes defined
Have you ever wondered what magic lies at the heart of child development? What allows a newborn to go from a helpless, screeching, squishy ball of flesh to an upright, mobile, dexterous, babbling toddler? What possesses a baby to unfurl himself, to lift his head, to roll over from back to tummy, to drag himself along the ground, to crawl on all fours and eventually walk… all within his first year of life? Just how does a baby know what to do?
Well, the answer… and the magic… lie in the set of reflexes, called the primitive reflexes (aka infant or neonatal reflexes). These reflexes are normal, automatic reactions to external stimuli – such as the movement of the head (vestibular), and things a baby feels, sees, hears or experiences – which occur without conscious thought. Like the act of breathing and the heart beating, these automatic reactions occur in the part of the brain at the back of the head called the brainstem or lower brain.
Simply stated, a reflex creates a loop that begins with a sensory stimulus to the brainstem, where all automatic reactions occur, and ends with a responding muscle contraction, creating a specific movement pattern. These reflexes facilitate baby’s progress through the stages of natural development.
The role of primitive reflexes
The primitive reflexes account for most movement patterns in the womb and during the first months of life. Several reflexes play a key role in the birth process itself and then in ensuring baby’s survival. In addition, they support the development of the higher brain – also called the cortex… our conscious brain – which controls muscle tone and movement, sensory integration, cognition, and learning skills.
It is none other than the reflexes that allow for a bottom-up connection of the body to the higher brain so that baby’s nerve networks can be fully connected, and baby can begin to act in a more conscious and deliberate way.
The primitive reflexes are said to be “integrated” when the higher brain takes over conscious and deliberate movement, thoughts and feelings, and the lower brain is no longer triggered by stimuli. Even after the integration of the primitive reflexes, they remain as the scaffolding behind voluntary and deliberate thought and movement. They can resurface, however, to ensure survival (aka fight, flight or freeze) when trauma or stress causes us to revert to the lower brain.
When there are incomplete or weak connections, a reflex is said to be unintegrated, active, or retained; consequently, the reflex will be triggered constantly thereby disrupting communication to the lower brain and blocking some information from reaching the higher brain. Unintegrated reflexes cause many problems – some serious, others less so – which can lead to a lifetime of learning disabilities, and emotional, behavioural and social issues.
The proper integration of primitive reflexes is essential to a child’s… a teen, an adult’s… ability to self-regulate and to organize and control the senses.
Primitive reflexes summarized
There are more than thirty different primitive reflexes. They all emerge in utero (in the womb) at different points during the pregnancy. They play a key role in allowing baby to go through the birth process, and each of them enable baby to automatically do the things that will ensure baby’s survival and development after birth.
The 14 primitive reflexes summarized here are the ones that, if retained past the age when they should be integrated, are consistently associated with causing brain imbalance and delays in development:
1. Moro reflex
First, we have the Moro reflex, which develops approximately 9-12 weeks in utero and should be fully developed at birth so that it can trigger the production of adrenaline and cortisol to help activate and give energy to baby during the birth.
As soon as baby is delivered and she arches her head back, the first part of the movement pattern of the Moro reflex is triggered: baby will fling her arms and legs open, which expands her lungs and allows her to take her first breath of life. She will then quickly pull in her limbs to assume a fetal position and may follow up with a good cry.
As the earliest primitive reflex to emerge, the Moro forms the cornerstone in the foundation for life and for living. It is baby’s survival and protective reflex… her fight or flight response. It is the only one of the primitive reflexes that has multiple sensory triggers, such as loud noises, a sudden movement or change of position, a frightening visual, or unpleasant feeling on the skin.
Ideally, this reflex is integrated by the time baby is 3-4 months old.
2. Asymmetric tonic neck reflex (ATNR)
The ATNR emerges at about 13 weeks in utero. It comes into play in the birth canal after the Moro reflex. It causes the first rotation of baby journeying down the birth canal, just like a corkscrew.
The ATNR is also called the learning reflex because it is critical for early hand-eye coordination. It is also referred to as the fencing reflex due to the iconic posture baby strikes when the reflex is triggered, and as the boxing reflex given that it is responsible for the little hand and feet jabs that are felt during pregnancy.
The ATNR is triggered when the baby’s head turns to one side in response to a sound or a visual cue while baby is lying on his back. Baby will extend his limbs on the one side of his body in the direction he is facing and will flex those on the opposite side of his body, hence the reference to fencing. On guard!
To develop all the benefits of this wonderful and critical reflex, baby should be spending more time flat on his back (not inclined or in an infant seat) so that he has the space and the conditions conducive to practicing his fencing and boxing moves.
One benefit worth mentioning here is the fact that these moves help to make neural connections between the right side of the body and the brain’s left hemisphere, and the left side of the body and the right hemisphere.
Ideally, the ATNR is integrated by the time baby is 6-7 months old.
3. Spinal Galant reflex
The spinal Galant reflex emerges at 20 weeks in utero.
This reflex is important for the conduction of body vibrations in the fetus and the development of the vestibular system, which is part of the inner ear and essential to auditory processing, the sense of balance and spatial orientation. It allows baby to invert while in the womb, to wriggle her way into a head-down position before birth, and to move down the birth canal.
The spinal Galant also contributes to the development of the muscles of the lower back, buttocks, pelvic area, and the back of the legs, which influences the up-down motor coordination system, as well as the development of the links between the legs and the core of the body. It prepares baby for creeping, crawling, standing and then for walking.
The Spinal Galant is triggered through a touch along baby’s spine or side from the base of the neck down to the top of the sacrum. Baby will respond by doing a little side crunch of the hip in the direction of the stimulus.
Ideally, this reflex is integrated by the time baby is 3-9 months old.
4. Spinal Perez reflex
This reflex emerges at birth and is active up to 2-3 months of life.
Along with the spinal Galant and the Bauer crawling reflexes, the spinal Perez helps orchestrate movements that are necessary for birth to progress. It involves baby lifting his hips to propel himself forward down the birth canal.
This reflex will help develop the Landau and the symmetrical tonic neck reflex (aka bridging reflexes), and eventually lead baby to get up on hands and knees to everyone’s delight. It influences the work of the cerebrospinal fluid (CSF) pumping mechanism (which, simply stated, is the movement of the clear body fluid that protects the brain and spinal cord from sudden impact) and helps pelvic movement for walking and toilet training.
The spinal Perez is triggered when both sides of the spine from the tailbone to the neck is touched or stroked. Baby will respond by extending his trunk, lifting his bottom and then his head, as in a back bend, while flexing arms and legs.
Ideally, this reflex is integrated by the time baby is 3-6 months old.
5. Bauer crawling reflex
The Bauer crawling reflex, like many of the other reflexes, appears around the 12th week in utero. It is active during baby’s birth and remains so until the third month of life at which point it is integrated into other movements that will allow baby to crawl.
The Bauer crawling reflex plays a crucial role, via cross lateral movement (moving opposite arm and leg at the same time), in helping to develop the nerve connections between the left and right hemispheres of the higher brain. This connection is called the corpus callosum. Bauer crawling is essential in the development of vision, hearing, coordinated movement, and mature cognition.
When pressure is applied to the soles of the feet of a newborn who is lying face down, she will make crawling motions involving the feet and their opposite shoulder. Later the opposing hand will reach forward. Baby might also lift her head.
There are several crucial times for anchoring the Bauer crawling reflex pattern for optimizing brain function. They are:
6. Tonic labyrinthine reflex (TLR)
This reflex has two movement patterns. The first, the TLR forward (flexion), emerges at about 3-4 months in utero and is triggered by baby’s head tilting forward causing immediate bending of the arms and legs. The TLR (flexion) helps the fetus to keep the embryonic or foetal position throughout the whole pregnancy.
The second movement pattern, the TLR backwards (extension), only kicks in at the time of delivery when baby needs to push her way out of the birth canal. As the head and neck extend backward, the whole body extends, as do the limbs allowing baby to straighten out immediately after birth.
The TLR backwards also helps baby to adapt to gravity after birth. It makes it possible for baby’s little bobbing head to lift when on her tummy. A child that does not learn to lift her head will remain helpless on the floor. The TLR allows neck muscles to get stronger, and influences muscle tone from the head downward. The TLR takes part in developing the control mechanisms for whole-body muscle tone and progressively supports the development of head control.
This strengthening and control are the basis for the movements of rolling over, crawling on all fours, standing, and walking. They ensure stability, equilibrium, muscle tone, proprioception (sense of position and movement of body in space), and balance.
Expected integration of the TLR forward is at 3-4 months of age until baby’s limbs slowly relax. Inhibition of the TLR backwards is a more gradual process involving the emergence of the bridging and postural reflexes, which may take up to age 3 to be completed.
7. Bonding reflex
The bonding reflex… yes, it is an actual reflex… is supposed to happen during the first seven minutes to one hour after birth when the birth is natural and successful, and when mum and baby are loaded with oxytocin, sometimes referred to as the love hormone.
The sensory-motor integration steps required to switch on the magic of this reflex are as follows:
1) Activation of the tactile system: Baby needs mum’s touch to create the tactile bridge between the pressure in utero and the new contrasting air pressure.
2) Activation of the visual system: Baby and mum must be given the opportunity to make eye contact with one another. Baby will respond well to seeing mum’s smiling face.
3) Activation of auditory perception and processing: Baby must hear mum’s voice greeting him at birth, and dad’s voice too, which baby may react to first because of its lower frequency.
4) Activation of the body posture system: Baby must have some tummy time on mum’s abdomen to trigger what is called the abdominal reflex pattern (the arm and leg on the same side as the face is turned are flexed, and the opposite arm and leg are straight). This position calms baby after the stressful birth by releasing tensions and stabilizing the stress hormones, adrenaline and cortisol, which are very high during the birth.
5) Activation of the motor system of crawling to the mother’s breast: Having baby on mum’s abdomen following the birth will activate his instinct to crawl toward her breast for feeding.
6) Activation of the survival instincts: Baby should be given the breast to activate the first sucking motions. This allows baby to trigger the coordination of sucking-swallowing-breathing reflexes, and to activate the nourishing reflex, which informs the body about feeling content with being nourished. The brain activates positive protection and survival strategies that will then work more efficiently in later years when stress situations and frustrations occur.
8. Rooting reflex
The rooting reflex emerges between 24 and 28 weeks in utero, which is why babies can be seen sucking their thumbs in ultrasound images.
After the birth of baby, mum can depend on the magic of facial/oral reflexes – such as the rooting reflex – and hand and feet reflexes to trigger baby to feed. The rooting reflex is, therefore, a life-preserving reflex that prompts baby to seek out a source of nourishment.
It is triggered by a light touch to the cheek or a light touch around the outside edge of the mouth. Baby will turn his head toward the stimulus and open his mouth wide enough, with extended tongue, to latch onto the breast or bottle in preparation for sucking.
The strength of the rooting reflex may come and go according to when the last feeding occurred. It disappears temporarily after baby is satiated but will reappear after some time has lapsed.
Although rooting is innate, turning toward the nipple or the bottle when it appears in the field of vision is not. Baby will be quick to learn, however.
Ideally, the rooting reflex is integrated by the time baby is 3-4 months old.
9. Sucking reflex
The sucking reflex can be observed in utero between 18 and 24 weeks but is not fully developed until approximately 36 weeks. Premature babies may have a weak or immature sucking ability because of this.
As you might expect, this reflex consists of sucking motions by the lips when they or the roof of baby’s mouth are touched with a finger, a pacifier, or a nipple. Instinctively, baby will begin to suck to ensure nourishment. Sucking and rooting reflexes also help develop mouth movements for eating and, eventually, for speech.
Around 2-3 months of age, baby’s sucking will be a result of conscious effort and no longer a reflex.
10. The Babkin palmomental (palm-mouth) reflex
The Babkin palmomental reflex emerges at 9 weeks in utero. After birth, it is active during the first 3 months.
The reflex is triggered by firm pressure to the palm of baby’s hand with an adult thumb or by ‘palming’ her own hand. In response to the pressure, baby will open her mouth, bend her elbows, and move her head forward towards her chest or turn her head to the side, if only one hand is being stimulated at a time.
The Babkin palmomental reflex is also triggered by the action of sucking. You may notice baby’s little hands kneading away at the breast during feeding. This innate movement stimulates milk production in mum.
The reflex plays an important role in the development of eating reflexes, such as sucking, swallowing, biting, and chewing. It influences the facial expressions and the dynamics of the movements of the skull bones. It is crucial for this reflex to be matured for later speech development.
Furthermore, the Babkin palmomental creates the basis for the development of the “palm-mouth” coordination system, which allows baby to bring different objects and toys to her mouth to explore their qualities, and later to develop her self-feeding skills.
Ideally, this reflex is integrated by the time baby is 4 months old.
11. Grasp reflexes
The palmar grasp (aka hands grasping) reflex emerges at the 11th week in utero. It is fully present at birth and is strongly active for the first 12 weeks of life.
It is believed that in the early stages of human evolution, this reflex would have been necessary for newborns to cling to their mother for safety. Grasping also allows baby to explore his surroundings through touch, which influences the development of gross hand-motor coordination, grasping and holding objects, manipulating bigger objects, and later the development of fine motor coordination of fingers for drawing, writing, and playing musical instruments, for instance.
The palmar grasp reflex is activated when the upper part of the palm of a newborn baby’s hand is touched with a finger, object, or surface. The response is a fisted grip. A baby’s grip can be so strong that he can be gently lifted from a lying position while grasping mum or dad’s pinky fingers. Caution needs to be taken when testing baby’s grasp, however, as he can tire and release his hold.
By 4 to 6 months, baby can pick up and hold an object with his entire hand. By approximately the 5th month, baby starts to gain the ability to let go of an object at will. At around 9 months, the fingers are differentiated enough for baby to use the pincer grasp.
The palmar grasp reflex is integrated by the end of the first year of life.
While the palmar grasp reflex is found in the palms of the hands, the plantar grasp reflex is found in the soles of the feet. Like the palmar grasp, the plantar grasp emerges around 11 weeks in utero.
The plantar reflex is triggered when pressure is applied against the sole of baby’s foot – vertically between the toes and the arch – causing baby’s toes to curl. This reflex will ensure stability, once baby can stand, and motor coordination for running, jumping, and climbing.
The plantar grasp reflex has a strong foot-to-mouth association. If baby’s feet are stroked while breast feeding, it can release lip and tongue reflexes simultaneously, which can help facilitate nursing in the same way the little “palming” (Babkin reflex) of baby’s hands can trigger or facilitate nursing.
The infant plantar grasp reflex will become the adult plantar reflex by the age of 2 when it presents as a downward flexion of the toes toward the source of the stimulus.
12. Babinski reflex
The Babinski reflex (aka the plantar reflex, extensor plantar reflex, or the Babinski sign) emerges approximately one week after birth and remains active for at least the first year of life. Since the discovery of the Babinski reflex, its testing has become a common part of newborn and infant examinations throughout the world.
The Babinski is important for developing the ability to move freely and for joint rotation, especially in the feet, ankles, knees, hips and even the jaw. It is essential for developing the coordination for crawling, standing, walking, and running, creating the foundation for balance and the feeling of being grounded and centered.
The Babinski reflex is triggered when the outside edge of the foot, from the heel to the base of the toes, is stimulated. When the reflex is present, the large toe extends upward and the other toes fan out.
The Babinski reflex may not be completely integrated until baby is 2 years of age.
13. Landau reflex
The Landau and the symmetrical tonic neck reflex (STNR) are not present at birth nor do they remain present for the remainder of life and, therefore, cannot be categorized as primitive nor postural reflexes per say. They are said to act as important “bridging” reflexes to allow more complex movements of crawling, creeping, and walking. They will not appear, however, if the previous primitive reflexes have not performed their magic.
The upper Landau (head, chest, and arms lift) appears between 2-4 months after birth, and lower Landau (legs lift as well as head, chest, and arms) appears between 5-6 months. The reflex is triggered when baby is lifted by the abdomen or pressure is exerted on the abdomen during tummy time on the floor, for example. Baby’s head, chest, arms, and legs will lift as though doing the airplane. The reflex is also driven by visual stimulation. Baby will look up, for example, to look at a familiar face.
The first task baby must accomplish is mastery of head control and muscle tone of the neck, chest, arms, back and legs before he can perform more controlled voluntary movement. As mentioned above, the TLR backwards is responsible for muscle toning during the first few months of baby’s life. The Landau reflex, which appears at 2-4 months, is key to furthering this development. Control is gained in the prone (tummy) position before it is achieved in the supine (back) position.
When baby can lift her chest from the ground, the arms become free to grasp things and bring them to her mouth. The movement toward the mouth helps develop near vision and convergence, which is the inward movement of both eyes toward each other.
The Landau reflex participates in the development of the STNR, which appears once the upper body is strong enough for the chest to be propped up with straight arms and the head to be held up. This prepares for higher level motor patterns, like standing, walking, hopping, jumping, and skipping abilities.
The life of the Landau is long, up to about 2 years. Final integration of this reflex into the whole-body movement system takes place between the 2nd and 3rd year, when a child can lift his head while keeping legs on the floor while in a prone position.
14. Symmetrical tonic neck reflex (STNR)
The STNR develops in baby between 6-9 months after birth. The STNR is the other of two bridging reflexes and, along with the ATNR and TLR, is considered a neck reflex because the movement of the head and neck activates changes in the arms, legs, and trunk.
The reflex pattern of the STNR involves two positions:
In both cases the head rising or lowering are driven by an auditory and visual stimulus, like hearing mum or dad’s voice above or seeing a toy on the ground.
Alternating between sitting pretty and downward dog allows baby to defy gravity and to adopt the all-fours position, a huge achievement in baby’s development. Baby will strengthen the muscles in her back and neck and learn to use the two halves of her body independently. Eventually, baby rocking back and forth – the “puppy bounce” – will lead to baby crawling on hands and knees, and with that, inhibiting the STNR reflex.
A baby “bum shuffling” or lagging one leg when attempting to crawl indicates that baby is stuck in her development.
The STNR causes vision to adapt from near to far and vice versa, as baby’s head bobs up and down during the STNR movement patterns, thereby training visual accommodation. Creeping on hands and knees further develops visual skills. It helps to develop intentional movement, controlling the position of the head and body for visual and auditory perception.
In addition to looking ahead, baby learns eye-hand coordination through the movement of the hands. At times, the eyes focus from one hand to the other, with the hands acting as moving stimuli.
Later, this ability will be essential for reading without losing the words at midline and visually following the moving hand when writing.
Ideally, the STNR is integrated at 9-11 months old.
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