SYMMETRICAL AND CROSS LATERAL LOCOMOTIVE REFLEX FUNCTION
Locomotor Reflexes are the primitive mechanisms that combine to move us forward (or backward). In some manner, we share these systems with all animals. These are dominantly Proprioceptive Motor Reflexes and sometimes labeled Tendon Guard Reflexes for their reliance on sensing tendon tension. Vision (not dominantly visual cortex) is most tightly linked to these primitives.
Overview of Locomotor reflex activity:
The evolutionary leap to movement stemmed from centrally organizing the processing of sensory inputs and directing responses, in other words, a central nervous system. Vision plays a dominant role in identifying what to move towards or away from. Animals organized bilaterally along a single axis (the spine) most successfully embody this evolutionary layer. For most of the history of animal movement, these movements were purely linear, oriented towards or away from a stimuli, or linear motion in the front / black plane. In animals, and in the neurology we have inherited, these actions are symmetrical, employing both sides of the body repeatedly performing same task, as in crawling, walking and swimming.
Although animals dominant in this layer often have capacity to learn, their underlying thinking processes are primarily genetically encoded, rather than learned. In our brains these regions are described as dispositional nuclei, which recognize patterns and respond: â€œIf this is so, then do that.â€ Learning a new stimulus / response pattern required evolving another dispositional nuclei. We experience how dispositional cognition is still fully engaged in our present moment awareness through our raw emotions, such as anger, fear and arousal being the primary response initiators. Decisions about movement options swing along an axis from projection, which is competition for energy and reproduction, and protection, which at this layer is Fight or Flight. The most famous of these dispositional nuclei is our Amygdala, well known for its role in processing aggression. When we experience an emotional response emerging 1 â€“ 3 seconds after stimulation, or responses of which we become aware of after the fact, we are observing our dispositional cognition at work. These raw emotions in their time were the state of the art in cognitive processing for animals that could move, and were more than adequate to populate the lands and seas with animals.
Movement requires complex interactions between opposing muscles and between muscles that act synergistically to generate the motion. These patterns of changing activation and inhibition through time are written in the deepest layers of our central nervous system and combine genetically encoded and trained skill, a combination of â€œhardwareâ€ and â€œsoftwareâ€. These are the locomotor reflexes. Training these reflexes requires repetitive movement. The quality of movement is quite different from that which we associate with exercises. Nerves establish new connections slowly, usually somewhere between 15 seconds and several minutes. This allows them to integrate multiple sensory / motor sets of inputs and not â€œover buildâ€ the functional network. Consequently, when training these systems, we need both slow movement or stationary holding against resistance, and many repetitions. It is not the strength of the muscle we are concerned with, but rather functional control of the action that the muscle performs. However, as functional control improves, muscle strength also improves as the muscle(s) and its antagonist(s) are working with stronger (cleaner / clearer) signals.
Here is a great example of this type of movement, which s intrinsic to more complex form of locomotion:
Locomotor Symmetrical reflexes rest on top of our visceral neurology. Here is a post on this subject: