Scientific Basis of Body Mapping, 2026

T. Richard Nichols, Ph.D.- ABME Scientific Advisory Board, Professor Emeritus

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Summary

An accurate body map, a term utilized by educators of the Association for Body Mapping Education, establishes a congruent relationship between the mechanical actions of muscles recruited for a given task and the motions and locations of the joints that are engaged to allow the motions.  Muscles are recruited in groups known as synergies that either stabilize or cause motions of the joints based on muscle attachments and the directions of motion allowed by the joints.  Some synergies are innate and associated with basic movements such as reaching and grasping.  Other synergies are acquired during learning of skilled movements.  The body map is a representation of the collective synergies for movement that resides in a distributed network of neural circuits.  These circuits are located across primary motor and sensorimotor cortices as well as a larger network spanning frontal, parietal and temporal lobes of the brain.  Subcortical areas and the spinal cord may be included in these circuits.  The primary motor cortex represents relatively simple synergies of single or closely related muscles, while premotor areas represent sequences of synergies that drive more global, learned motions of the body.  Sensory areas in the parietal cortex that integrate kinesthetic information with sensory feedback from the organs of hearing and seeing guide the selection of muscle synergies selected in premotor areas. Sensory information is also used to update and refine the body map with growth and experience, and to adapt the Map after damage to the musculoskeletal system.  In the case of “mis-mappings,” the actions of synergies are not congruent with the allowed motions of the joints.  Such distortions can be corrected with training. 

Introduction

The concept of the body map used by the Association for Body Mapping Education essentially constitutes a “how to” manual describing the proper use of the body to move efficiently and effectively for musical performance and other activities, and to avoid injury.  The term “body map,” as well as the related term “body scheme,” are used frequently in various contexts in the motor control literature.  Individuals are said to have accurately mapped the motions of the joints of the body when these motions are harmonious, or congruent with the anatomical structure of the joints and their locations within the skeleton.  Most motor areas of the brain and the spinal cord contain representations of the structure of the musculoskeletal system, so it remains to determine the correspondence between these representations and the body map as used here.

What is represented in the body map?

To understand the biological basis of the body map, we can ask two fundamental questions, namely, 1) what is represented in the map, either structures, functions, or both, and 2) where are these representations located in the central nervous system?  Starting with the former, consider that movements should be congruent with the organization and function of the musculoskeletal system, so that muscular action matches the motions allowed by each joint. At one level, the locations and allowed motions of the joints must be represented in the body map, but perhaps indirectly.   Since joint motions or stabilizations are caused by muscular action, and sensory information about what is happening in the musculoskeletal system comes in large part from muscles, motions of the joints may be represented through muscular action.  Development of an accurate body map then ensures congruence between the musculature and skeleton.

Congruence between muscle action and joint motion

Each skeletal muscle exerts force (or more properly, torques) about one or more joints and in given directions of motion at each joint that it crosses. The specific actions of each muscle have an anatomical basis which depends on the attachments of the muscle and the routes of force transmission through tendons and fascia. Muscles then cause forces leading to motions that depend on the geometry of the joint that constrains movement in different ways and to different extents.  For example, the elbow is constrained to move mainly in flexion and extension, whereas the glenohumeral joint allows flexion, extension, abduction and adduction of the shoulder, and rotation about the long axis of the arm.  Given the complexity of musculoskeletal anatomy, the question arises as to how muscles are recruited to exert forces that match these allowable motions.  The answer is that, since most joints are crossed by more than one muscle, muscles are recruited in groups that collectively move the joint(s) or stabilize them in the permitted directions.  In an accurate body map, there is an optimal relationship between the actions of the recruited muscles and the permitted directions of motion.

Muscle synergies

Although it is possible to recruit some individual muscles voluntarily, with the resulting actions due to joint structure, muscles are almost always recruited in groups known as synergies.  The expression of each synergy results in a specific action, either a motion or a stabilization of the associated joint or joints.  Some synergies are innate, while others are learned during the acquisition of skilled movement.  The innate synergies are in most cases congruent with normal joint motions, and synergies associated with learned movements are congruent with joint motions following proper instruction and practice.  Next, sequences of synergies, which can also be innate or learned, then result in the complex motions of the body that we know of as motor behavior.  For example, when pressing closely spaced piano keys in one musical passage, some muscle synergies may be used to stabilize the elbow while sequences of other synergies cause individuated movements of the fingers and wrist.  In another musical passage, where more global motions of the arm may be required to access keys across the keyboard, a different sequence of synergies involving elbow and shoulder motion would be required.  We can think of synergies as part of the internal language of the central nervous system.

The body map represents muscle synergies

We can therefore define three levels of organization in recruiting the musculature, namely, recruitment of individual or closely related muscles, individual synergies, and sequences of synergies.  In order to control these actions and repeat learned motor skills, the central nervous system must contain a representation of all three levels of organization (there are more levels, of course, such as those that affect the overarching interpretation of the music).  We can now understand that body maps represent not only anatomy of the musculoskeletal system but also how muscles are used to perform desired actions.  The term “actions” is employed here, because muscles are used either to produce motion or act to provide stabilization of joints where no motion results.

Where in the central nervous system is the body map located?

Muscles and movements are both represented in the body maps of the brain

The British neurologist John Hughlings Jackson posed the question as to whether muscles or movements are represented in the cerebral cortex and opined that movements, rather than muscles, are represented.   We can partially answer this question, since muscle synergies are structured to mediate particular movements.  The primary motor cortex is an executive area of the brain that projects directly and indirectly to muscles and groups of muscles and is organized around a map of the body.  Cells in the motor cortex may project to several muscles with complementary actions, providing a basis for simple muscle synergies.

In addition, different synergies involving the same muscle groups may be represented in the primary motor cortex.  For example, Donald Humphrey, a renowned neuroscientist who investigated motor control in the primate brain, studied the patterns of activity of neurons in the wrist area of the motor cortex along with the patterns of activation of wrist flexor and extensor muscles.  He found two groups of neurons, each in a distinct location, that made connections to the same flexor and extensor muscles of the wrist.  However, one group of neurons became active during alternating flexion and extension movements, while the other group was active when the same flexors and extensors were activated simultaneously to stabilize the wrist. This example shows one way in which both muscles and movements, or actions, are represented in the primary motor cortex.

The body map occupies a distributed network across the frontal and parietal lobes

According to recent studies, synergies that are directly represented in the primary motor cortex tend to be associated with simple actions, such as flexion, extension, or stabilization of the joint. The primary motor cortex therefore represents the first level of organization of the Map, namely single or closely related muscles. Further, the motor neurons in this cortex receive information directly from the same muscle groups by way of the primary somatosensory cortex.  This information immediately leads to the conclusion that the elaborate sequences of synergies that underlie natural movements must be represented in other, motor planning, areas of the brain, and that the primary motor cortex provides executive action to activate motor nuclei in the spinal cord and brainstem.  One can then think of the simple synergies represented in the primary motor cortex as the building blocks of the desired movement. Two of the motor areas that have been implicated in representing these synergies are the premotor and supplementary motor areas (SMA).  These areas are located just rostral to the primary motor cortex in the frontal lobe and project to the primary motor cortex to recruit the required muscle combinations.  Research indicates that the supplementary motor area mediates sequential motions that are internally generated, while the premotor areas mediate motions triggered by external stimuli.  The relative roles of these areas in motor control are under further investigation, but they both likely contribute to the recruitment of muscle synergies for skilled movements and therefore contain critical components of the body map.

The network housing the body map is not limited to what are considered motor areas in the frontal lobe.  It has also been observed that lesions of areas in the parietal lobe (posterior parietal cortex) result in severe disruption of motor coordination.  In addition, other research on healthy human subjects and on animals indicates that the body map resides in an extensive network spanning the parietal, frontal and temporal lobes. Imaging of brain areas that are active during the learning of skilled movement and tool use have shown activity across this network. Furthermore, the fact that parietal areas also integrate information from the special senses (hearing and vision) and somatosensory sources (such as skin and muscle proprioceptors) is consistent with the role of these sensory inputs in modulating the expression of muscle synergies during musical performance.

As is the case for most brain processes, the body map is continually reinforced, updated or refined based on sensory input from the body and from the perception of the musical performance.  As we grow, age, and adapt to injury and disease, any changes to the musculoskeletal or nervous systems must be accommodated by changes to the Map as well as changes to other physiological systems that might be affected.  For example, in the case of muscle weakness or paralysis, the patterns of force output of the associated muscle synergies will be affected with consequences for the congruence between joint motion and the associated synergies.  Alternate strategies then must be adopted to move in an efficient and effective manner through adaptive processes.

Distortions of the body map

If the body map is inaccurate, then the synergies selected for a given task may not be congruent with the functions of the associated joints and their spatial locations that would ordinarily be used to complete the task.  Furthermore, since kinesthetic feedback arises mainly from muscles, the resulting altered sensory feedback could disrupt the perception of the ongoing motion and judgement as to where in the musculoskeletal system the motion is taking place.  These processes occur in the cortical areas, described above, that mediate both innate and learned movements.  

Conclusion

The body map operates behind the scenes, below the conscious level, for both innate and learned movements.  Introspection during self-observation of our movements can make the Map apparent to the individual, allowing for any corrections to be made to increase efficiency and congruence.  An important role of the ABME educator is to ensure that the consciously perceived map is congruent with anatomy and mechanical function.  It is a common observation among educators that musicians having trouble with both execution of the musical performance, and/or with discomfort possibly leading to injury, either have not consciously explored their maps or have maps that are not congruent.  An important question is whether either of these conditions is specific to musical performance or applies to all movements of that individual, both learned and innate.  In either case, training can be used to consciously perceive and update the body map, bringing it into congruence with the structure and actions of the musculoskeletal system.