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  • Writer's pictureDr. Stephens-Sarlós Erzsébet

Primitive reflexes and the "immature" brain

Approximately a year ago, a Canadian research group (Laliberte, Farah, Steiner, Tariq, Bui) reported on an extremely important study. They examined how the grasping reflex is inhibited in mice. They mapped the sensorimotor processes, neurotransmitters, sensory, motor, and associative pathways that play a role in inhibiting the reflex (i.e. make it “go away”) after a certain period of time.

The brain

They found that as the cerebral cortex reaches the appropriate level of maturity, and automatic movement is replaced by voluntary movement, the cortex initiates the process in which the grasping primitive reflex is inhibited.


Why is this important? Firstly, because it has been demonstrated that appropriate maturity of the cerebral cortex is necessary for the inhibition of each specific primitive reflex. Looking at the question in reverse, we can also state that if a primitive reflex can still be triggered after a certain age, it indicates immaturity of cortical functions, or that there is some neurological problem.


Let's take a look at what symptoms or symptom clusters can trigger (even in adulthood) the primitive reflexes which should have been inhibited around the age of two and a half to three years.


In the children I tested (if we consider just the last three years, which includes nearly two thousand children), unintegrated primitive reflexes can be found underlying the ADHD symptom group, certain autistic symptoms, as well as issues with toilet training, fecal retention, delayed speech development, speech perception and articulation difficulties, swallowing problems, behavioral issues, clumsiness, and difficulties in writing and reading, and even some anxiety symptoms and self-esteem problems.


Girl with a sticker on her forehead

How is it possible that such diverse disorders result from unintegrated primitive reflexes? The answer lies in the diversity of the reflexes themselves. Each of them plays its own role in an infant's life. Some lay the groundwork for speech development, while others help the baby differentiate itself from the world, perceive the boundaries of their own body, and develop spatial awareness. Other reflexes contribute to hand-eye coordination. Some are involved in sitting or standing. Several reflexes serve a protective function, and indirectly or directly, they all influence muscle tone.


In cases where certain reflex(es) were not properly triggered in the first few months following a baby's birth (or some reflexes were triggered later than usual), it means the associated pathways and cortical areas did not receive enough stimulation to mature. The immature cortex interprets that it still needs the movement generated by the primitive reflex(es), so it does not inhibit them.


One can imagine this as the cortex being "hungry." It can only be satisfied when adequately nourished. The reflex movements triggered by sensory stimuli serve as "food" for the cortex. It will not say, "Thank you, I'm full, I don't need more!" until it's "full." Once it receives enough "nourishment," it sends the signal that it no longer needs to eat. This is when infantile reflexes disappear because there is no need for more of this type of "food."


It's no coincidence that there is a common factor in the diversity of symptoms: IMMATURITY. This can manifest in immature behaviors, immature movement patterns, immature pencil grip, bedwetting, tantrums, an inability to read, fatigue; and the list goes on.


Funny brains

Why can certain exercises be performed which will inhibit primitive reflexes? Because these exercises stimulate the pathways and cortical areas responsible for inhibiting the specific reflexes.


For those who want to know more about the topic, they can find detailed information in my book, which also contains recommended exercises. I also offer a sets of reflex integration videos for specific problem areas like ADHD, Sensory Disorders, ASD, Speech Development, Dyslexia, Bedwetting, and more.


And this is also important! When the cortex loses its activity in old age or due to certain illnesses, primitive reflexes can reemerge. What can be done in such cases? You've probably guessed it; you need to exercise, and to perform reflex integration exercises.




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