Child Brain Development - Podcast 6

On episode #6 of Brainstorm Bites, we look further into child brain development and the impact primitive reflexes (PR) can have on brain development if they are retained or not fully integrated during the first 6-12 months of life. 

Functions of the higher centres including behaviour, learning, gross or fine motor movements, structural problems, hormonal imbalances and more may be impacted should primitive reflexes remain present. We look into three PR’s, Moro Reflex, Asymmetrical Tonic Neck Reflex and Tonic Labyrinthine Reflex. Listen to the podcast to learn more.


The previous episode highlighted the frontiers of neuroscience with childhood development. During that edition, we discussed hierarchical development. Hierarchical development occurs in stages and each stage is like a stop at a train station. For more information click onto the previous episode of Brainstorm Bites, episode #5 - ‘The disorganised brain and its impact on learning’. 

An area of childhood development that is often overlooked are early childhood reflexes. During the early months of life, the central nervous system is not fully developed. The needs and functions as a child are assisted by involuntary reflexes, or Primitive Reflexes (PR). It is understood that these primitive reflexes are vital for survival and development in the early months of life. As the brain begins to mature these PR are integrated into higher centre control.  

The PR should be fully present at birth and are gradually integrated during the first 6 to 12 months of life. Sometimes these reflexes are retained or not adequately integrated. If this occurs, they can disturb some or all of the functions of the higher centres, which includes behaviour, learning, gross or fine motor movements, structural problems, hormonal imbalances and more. 

From research and experience, it appears that trauma of some kind, somewhere between conception and the early months of life causes the PR to be retained. The injury can be physical, chemical, hormonal, or other forms not yet researched. The significant factor appears to be birth trauma, including caesarean section and any induced delivery.  

A practitioner assessing childhood development should appropriately consider and correct retained PR. The corrections are very gentle and allow the body to integrate the reflexes that have been inappropriately retained. In some cases, all of the PR will have been retained, while in other cases there may be only one, or some present.  

The corrections assist people of all ages, from babies and children to adults. After integration, clients may notice improvements in behaviour, learning, coordination, mood and anxiety levels, hormonal balance and chronic structural conditions, to name a few. Some examples of retained primitive reflexes are: 

1. Moro Reflex 

The Moro Reflex is a normal reflex for an infant when they are startled or feel like they are falling. It is an involuntary reaction to threat and acts as the earliest form of 'fight or flight' response. It is set off by excessive information in any of the baby's senses, for example, a loud noise, bright light, or sudden stimulation of the balance mechanism, such as dropping or tilting.

If the Moro Reflex is retained beyond 3 to 6 months of age, it becomes an automatic, uncontrollable overreaction and may result in:

• Hypersensitivity to sudden noise, light or movement, and so the child may withdraw from situations or have difficulty with new or stimulating experiences

• Poor impulse control. Hyperactive behaviour.

• Stimulus bound effect (cannot ignore peripheral stimuli to focus attention on one thing – has to pay attention to everything)

• Anxiety (particularly anticipation anxiety)

• Emotional and social immaturity

• Sensitivity to certain foods or food additives (which in turn affect behaviour and concentration)

2. Asymmetrical Tonic Neck Reflex

The Asymmetrical Tonic Neck Reflex (ATNR) should be fully present at birth and appears to assist the baby's active participation in the birthing process. It is activated as a result of turning the head to one side. As the head is turned, the arm and leg on the same side will extend while the opposite limbs bend. The reflex continues after birth and plays an integral part in the development of hand-eye coordination.

 If the ATNR remains active in a child beyond 6 months of age, it can affect:

• Hand-eye coordination (difficulties such as the ability to control the arm and hand lead to poor handwriting)

• Ability to cross the vertical midline (for example, a right-handed child may find it challenging to write on the left side of the page)

• The discrepancy between oral and written performance

• Development of lateral eye movements such as visual tracking (necessary for reading and writing)

• Control of automatic balance

• Bilateral integration (ability to use both sides of the body individually or together)

• Establishment of a dominant hand, eye or ear may be difficult

• Visual tracking and judgment of distance may be affected

• Poor at sport

• Chronic shoulder and/or neck problems

and our final example of PR is;

3. Tonic Labyrinthine Reflex

The Tonic Labyrinthine Reflex (TLR) is elicited by bending the neck forward or tilting it backwards or tilting the neck sideways. It involves the sense of balance and position in space. When the neck is tilted backwards, the limbs straighten, when the neck is tilted forwards the limbs bend.

If the TLR persists beyond three and a half years of age, it can be associated with:

• Postural problems, specifically hyper- or hypotonic muscles

• The tendency to walk on the toes

• Poor balance

• Motion sickness

• Orientation and spatial difficulties

• Visual-perceptual problems

• Difficulty judging space, distance, depth and speed

• Fatigue while reading or when working or studying at a desk

Appropriate therapy and rehabilitation is vital to support the child's developing brain function.

At Brainstorm, we are dedicated to switching on brains. For references and information, jump to brainstormrehab.com.au or join the conversation on Facebook. On our website we have considerable content, rich with videos and details about childhood development and therapy. Thanks for joining us today on the Brainstorm Bites podcast.

(Bexander & Hodges, 2012; Lisberger, 2009)

(Greenspan & Wieder, 1999)(Melillo & Leisman, 2009)

More Reading

Bexander, C. S. M., & Hodges, P. W. (2012). Cervico-ocular coordination during neck rotation is distorted in people with whiplash-associated disorders. Experimental Brain Research, 217(1), 67–77. https://doi.org/10.1007/s00221-011-2973-8

Greenspan, S. I., & Wieder, S. (1999). A Functional Developmental Approach to Autism Spectrum Disorders. Journal of the Association for Persons with Severe Handicaps.

Lisberger, S. G. (2009). Internal models of eye movement in the floccular complex of the monkey cerebellum. Neuroscience, 162(3), 763–776. https://doi.org/10.1016/j.neuroscience.2009.03.059

Melillo, R., & Leisman, G. (2009). Neurobehavioral Disorders of Childhood: An Evolutionary Perspective. New York: Springer.



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