Walking and Thinking and Exercise

As crawling continues so do the neurological inputs and outputs in the nervous system; particularly in the central nervous system, of which the cerebellum, thalamus, and cerebrum are integral.

As they develop, infants fling their arms and legs in uncoordinated movements until
they accomplish the difficult task of crawling forward. To do this they use their arms and legs in the first coordinated patterns; right arm with left leg moving forward, then left arm with right leg moving forward. Crawling is one of the first times that major neurological organization begins to take place in the infant.

As crawling continues so do the neurological inputs and outputs in the nervous system; particularly in the central nervous system, of which the cerebellum, thalamus, and cerebrum are integral.

The Cerebellum
The cerebellum coordinates movement and controls balance by receiving sensory information about the position of the joints and the length of muscles, along with information from the auditory, vestibular, and visual systems. It also receives instructional motor input from the cerebrum for automatic coordination of movements and balance.      

The Thalamus
The thalamus is a major integrating center for sensory input to the cerebrum and the main output center for motor information leaving the cerebrum. Incoming information from the senses tracks into the thalamus and output to the appropriate higher brain centers for further interpretation and integration. The thalamus also receives information from the cerebrum and from parts of brain that regulate emotion and arousal.   

The Cerebrum   
The two halves of the cerebrum are the most complex integrating centers in the nervous system for both conscious and unconscious movement. However, a large portion of skeletal muscle movement is determined by reflexes through the spinal cord or lower brain, without involving integration of information at the cerebral cortex level.  

Crawling
Crawling is one of the first developmental stages which coordinates the brain with the body. Crawling is controlled falling. As the infant continues crawling successfully the body coordination continues until such time the infant begins walking and rarely ever returns to crawling.

During forward motion, there is vast and important communication between the frontal lobe and the contralateral cerebellum as well as vestibular and ocular coordination.

The Cerebrocerebellum in Movement
The cerebral cortex needs information about the desired movement before reaching neurological threshold to fire for the desired response. This information comes from the cerebellum which sends information to the thalamus and then through thalamocortical fibers which project up to the frontal lobe.   

The cortex then sends projections back down to the midbrain which then decussate back into the cerebellum via the middle cerebellar peduncle. This input informs the cerebellum about the response that is about to be generated. This is a feed-forward mechanism; the cerebrum receives information from the cerebellum regarding the movement about to take place.

Almost simultaneously, projections come from the cortex via lateral corticospinal fibers for integration into ventral horn cells for motor output to perform the desired movement.

Cerebellar-Cortical-Spinal Loops:
Before the cortex decides to move a limb the cerebellum fires to inform the brain of where the body is in space and give the proprioceptive state of the body. If you want to move your left arm, the left cerebellum fires up through a feed forward mechanism to the contralateral mesencephalic red nucleus, then fires to the right thalamus and then the right cortex. This information excites the right cortex, informing the brain what the left cerebellum requires before moving the left hand.   

Now that the brain is activated for movement of the left arm, two things will happen simultaneously:

• Information from the feed forward mechanism (cerebellum to contralateral cortex) will feed back to the originating left cerebellum. This input contains information about cognition, position, and correction; in other words, the brain sends input about what it wants to do and checks in with the cerebellum before sending efferent signals to the left arm.
  
• There is also information feeding down to ventral horn cells from the cortex for integration into segmental movement of the left arm.
  

So we have an idea of movement to move the left arm. The left cerebellum first sends information to the right cortex about where the body is in space and how much movement will be needed to move it accurately, if accuracy is involved. Then the cortex sends information to the cortex of what seems a reasonable movement according to the information the cerebellum sent. Then the cortex fires down the spinal cord to the left upper extremity and the movement takes place.

Crawling
In a quadrupedal posture, crawling occurs when the coordination of the left upper extremity is acted upon for flexion motion along with right lower extremity for flexion motion (along with many other intricate motor outputs). Simultaneously, there is inhibition of motion to the opposite paired limbs until the cycle reciprocates.

Walking
Walking involves similar neurological input and output as crawling except in a bipedal posture; left arm swing with right leg, right arm swing with left leg. In just weeks or months of activity this motion pattern becomes plasticized and the gait pattern is unconscious and remains so until there is an injury, a stroke affecting one or more limbs, or in early neurodegenerative states that causes faulty gait patterns.

Faulty Gait Patterns
As one ages the gait cycle may wind down or, subsequent to an injury, the gait cycle may be compromised. In any case, the entire coordination and control of the nervous system may become inept. There may be less left arm swing because of a shoulder injury and a possible shorter right leg swing accordingly. The Parkinson’s pattern often first exhibits as a non-swinging arm and leads to the characteristic shuffle gait.

Exercising faulty gait patterns and integrating the nervous system
A series of specific exercises may re-integrate the nerve pathways.

1. Even though exercising the legs has a higher rate of firing the cerebellum than the arms, both arms and legs should be taken through there full range of motion so the subject gains more spindle input and more feedback into the system. Yoga, pilates, callanetics, and any other type of full range of motion exercise works towards re-integrating the nervous system. The exercises and movements which involve full body, large range of motion, provide greater activation of the brain, improved gait, and a higher state of alertness and pleasure.
   
2. Because the cerebellar-thalamus-cerebral system activate parts of brain that regulate emotion and arousal, when they are adequately activated, not only does movement occur, function improves, and patients just feel better. In other words, movement of the body activates the brain, helps the person feel better and truly affects their quality of life.
   
3. Cerebellar firing into the mesencephalon will activate the reticular activating system which is responsible for regulating wakefulness, sleep-wake transition, and all levels of consciousness. The greater use of arms and legs in a gait pattern will fire to activate more of the brain and promote fuller development.
   

Cross Crawl in Re-integration
Cross crawl is also a type of repatterning exercise. This exercise is described as a patient lying supine and the coordinated movements between one appendage and its contralateral mate passing through complete flexion and extension motion, while the opposite appendages follow the same pattern afterward. In other words, the person is crawling while on their back but in complete range of motion at the hip joints and the shoulder joints. This type of motion helps re-integrate the neurological pathways described above.

One important aspect is that the accomplishment of the crawl or gait-like motion is more important than the speed in performing the exercise. The brain and nervous system will more fully integrate as more of the entire motion is accomplished. Also, it is particularly important that there is as complete range of motion performed as is possible. In addition, as more of the extremity joints and muscles are activated, the spine must also simultaneously fire to promote shunt stabilization control. This involves more spinal activation in an effort to balance the body.

Cross crawl has had many variations including crossing one limb midline to the opposite paired limb (left hand touching right knee). As well, specific vestibular and ocular inputs can added in the clinical setting to cross crawl patterns for therapeutic benefits.