Models and Theories on Locomotor Activity

Walking and motion are coordinated events which involve alternating the halves of the body to be in excited or inhibited states, in order to create fluid propulsion and momentum.

In an effort to get closer to the truth, the following theories have been proposed by scientists to explain locomotor activity. But, a large question mark remains and more research definitely needs to be conducted!

The general understanding is that forelimbs and hindlimbs belong to independent circuits and their coordination comes from the interaction between rhythm-generating excitatory neurons and pattern-generating neurons.

Yet, when it comes to defining just how these neurons interact to create a coordinated, rhythmic output, a consensus is lacking.

The following models are currently available for describing how locomotor activity is rhythmically coordinated:

The classical half-center model describes all walking as extensor and flexor bursting which occurs as a result of “two reciprocally coupled half-centers”.

The flexor burst generator model, on the other hand, explains locomotion through a “flexor burst generator” which can excite flexor motor neurons and inhibit extensor motor neurons.

The unit burst generator model proposes a slightly more complex explanation for locomotor activity, as a result of the acquiring evidence that a central pattern generator exists. The idea here is that distinct, separate modules can create a rhythm within neighboring muscles which are located around a joint; a system known as the unit burst generator. Then, these unit burst generators (which create local rhythmic patterns and activity) combine to form a network with multiple, interconnected rhythm generators.

The Importance of Locomotor Activity

In humans, locomotor activity is basically the motion and movement required to get from one place to another. How else could we get up from the couch and go get the remote controller that somehow made its way across the room?

But, perhaps more importantly than that, locomotor activity is intricately intertwined with complex human activities, such as:

Learning

Motivation

Locomotor activity is necessary for approaching or avoiding a target, stimuli, or big-picture goals. These tendencies (of seeking or avoiding) are at the core of the human experience, of understanding motivation and learning.