Sensory information dictates our perception of the world around us-whatever world that may be to you. That world may be walking down the street feeling the sunlight on your face, holding a barbell in a gym, or sitting at a table holding a loved one’s hand. Our brain needs accurate sensory information from our environment, in order to connect. Sensory information includes the linkage of both the external environment (sensory) and internal environment (emotions). Representations of our environment can occur with both real and remembered stimuli (1). Human behavior and motor control is based upon ACCURATE sensory information (19,21,22). Vision, vestibular, and somatosensory (pain, touch, temperature, and proprioception) input provides our brain with the information it needs to make accurate motor and behavioral responses. The brain needs this afferent information in order to feel safe and know that it can protect itself against threat. You need the ability to sense and feel.
“[The brain is the] first and primary interface between the physical and social environment and the biological self and that is continuously adapting to allow an ongoing match between internal resources and external demands” - Ganzel, Wethington, & Morris, 2010
Let’s use a pacinian corpuscle receptor as an example of ascending pathways to the brain: A pacinian corpuscle receptor (mechanoreceptor) provides the sense of touch within the skin, more specifically it is ideal for detecting vibration and is found deep within the subcutaneous layers of the dermis. When the receptor is deformed by mechanical stimulation it triggers an action potential in the nerve. The afferent nerve signal by the transmission of neurotransmitters between neurons will enter the ascending pathway to the brain via the spinal cord. Depending upon the type of receptor, the sensory signal will cross over to the contralateral side at either the level of the spinal cord or medulla (depending on the sensory tract of somatosensory receptor). The signal will then reach the thalamus which functions as a relay station to other locations within the brain. The long path will involve sending the sensory message to the cortex, more specifically a location within the somatosensory homunculus. The somatosensory homunculus is basically an area of the brain that is a map of your body (for the location of signals). The cortex allows us to interpret the sensory signals logically. The information is processed and integrated with other sensory signals, locations, emotions, and all other environmental context.
If sensory information is labelled a threat the thalamus will relay the signal via the short path to the amygdala and produce a reaction. The amygdala is associated with fearful, anxious, and avoidance-related behavior. The processing of stimuli can have a threat or reward value called emotional stimuli (6). Although the regions of the brain are highly interrelated, the amygdala is suggested to control incentive values of reward by governing the amount of dopamine available to key regions of the basal ganglia associated with approach behavior, motivation, positive incentive (8,18).
The processing of stimuli can have a threat or reward value called emotional stimuli (6). A lack of sensory information from receptors due to decreased concentration and/or sensitivity can potentially be perceived as a threat. This can occur in different areas or SIDES of the body. This can be adaptable via incentive values of reward and allostatic load-related alterations. Adaptations that occur from lack of or limited sensory stimuli can change our physical processes (proprioception) and behavior. Dopamine has been suggested to modulate sensation-seeking behavior in humans (16) and is activated by sensory stimuli (20), more specifically tactile skin stimulation (12).
The social environment is one of the primary sources of information, but when we think of social, we think about connections with other humans. But what if our relationship with the physical environment is a social experience? In behavioral research, instability of social relationships, such as the type of dominance hierarchy show an association between glucocorticoids and social rank (relationships vary among species; 2). However, what if lack of afferent signals (perceived as a threat) is an unstable social experience? Could this unstable social experience result in physical instability and impingement? Lack of afferent messages may be perceived as a threat and result in a chronic stress response; affecting the hypothalamic-pituitary-adrenal (HPA) axis. Stress load-related alterations can decrease behavioral flexibility, changes in neurotransmitters, neurohormones (serotonin, dopamine, norepinephrine, & CRH) (6), and body rotation. Let the dominoes fall in line…
The term allostasis identifies the brain as the central mediator of physiological adjustments to environmental challenges and allows the organism to adapt to circumstances over time (6). Chronic or repeated stress can result in physiological adaptations that become entrenched and automatic. Stress is integrated and connected to sensory and motor systems, body position, level of physical tension, emotions, and behavior.
Stress pulls us to the right and into an extended position. It does. The brain preferentially shifts the body into certain, predictable states and positions due to stress which cause compensations in the body. When you are stressed, you increase recruitment of extensor muscles and increase muscle tone. You also have a predictable neural pattern to orientate yourself to the right. Why? It’s the pull of your right diaphragm, it’s the pull of your left brain, it’s the asymmetry of sensory systems, it’s the increase in extensor muscle tone, it’s the direction of blood ejected from the heart, shit maybe it’s the pull of the earth’s rotation.
Deafferentation or the interruption of afferent messages can lead to OR be the result of a right oriented, extended body position (stress). Our allostatic adaptation to deafferentation is reflected in a feed forward cycle of altered proprioception; thus the altered position becomes normalized. The brain’s sensory maps (somatosensory homunculus) can be reshaped by sensory deprivation (11). Sensory maps are how we reference movement, how we know the location of a stimulus, and understand where our body is in space. Several studies examining sensory deprivation in adult mice (removal of whiskers) indicated altered cortical areas or ‘maps’ of deprived sensory inputs and the expansion of maps of intact sensory inputs (5,11,24).
Lateral shift (to the right, in this example) results in neuroplastic changes in the brain to modify an individual’s estimate of limb position (10). An altered reference frame for limb position and movement occurs and is associated with sensory adaptations. Sensory adaptations can occur in response to efficient resource allocation to an environment (7). Neuroplasticity is central to the development of human motor function and is changeable, and adaptive. Motor learning affects not only motor areas of the brain but changes sensory function, as well (17). Remapping of the sensory system within the primary somatosensory cortex (more specifically the somatosensory homunculus) occurs with motor learning (17). Ostry et al. (17) examined changes to somatosensory function/estimates of limb position that were dependent upon motor learning. Subjects that received passive limb displacement through the same kinematic paths but without motor learning showed no evidence of sensory changes.
Alterations in concentration and sensitivity of sensory receptors can occur in this positional pattern; for example, right joint capsule receptors can become more responsive to direction and speed of capsular stretch than compared to the left side. Greater neural input and positional awareness occurs within this position (right lateralization). Upregulation of afferent receptors can occur on the side that endures a greater demand (right) and be downregulated on the opposite side (left). This can become normalized in a feedforward system (new reference frame). To create change, one must be able to sense and feel positions. According to Rossi and Grigg (23) the most important movement of the hip is internal (IR) and external (ER) rotation as the most receptors in the hip respond to these movements; IR/ER activates receptors in the posterior and anterior capsule. What does this look like?
Figure 1-3. The athlete above has bilateral hip impingement, lack of sensation and control during movement, and communicates feeling of foot cramping (grabbing the floor). Athlete may perceive the world right side orientated via an altered reference frame. Figure 1. Hypertrophy of vastus lateralis due to right side dominance. Figure 2. Athlete’s perceived normal (right oriented) reference frame and rib flare indicating extended position. Figure 3. Shows loading and explosive movement through the right side during a countermovement vertical jump.
When we view the world through a threat perception, we lose sight of our world. We react, instead of process. We need an anchor, physical or theoretical.
Biases can be expressed as increased body rotations toward one side” – Mohr et al., 2004
Orienting biases implicate a preferred and consistent direction of attention or locomotion toward one side of space and can be attributed to the imbalanced activation of brain hemispheres (9,15). Stress can be physical and emotional events, such as pain, discomfort, injury, or distress. However, stress can also be a sense of anguish inside that you don’t know or understand that could possibly be due to lack of sensory information to the brain. A stressed system on an unconscious level can create a cortical response (HPA axis) that leads to chronic stress states and resetting neural pathways.
Lack of sensory information, processing, integration, and/or interpretation can result in psychiatric disorders, overtraining, and sensation-seeking/addictive behavior.
- Lack of sensory information or the inability to connect can result in physical instability and impingement. Grabbing the floor with feet can be result of brain wanting information about position and inability to feel the floor/environment underneath the individual.
- Disrupted “intrinsic connections linking sensory information and emotional context for selective attention and action in prefrontal areas can result in disorders that are characterized by distractibility such as attention-deficit/hyperactivty disorder (ADHD)” (1). In a 2011-2012 National Survey of Children’s Health conducted by the U.S. Centers for Disease Control and Prevention, that included 75,171 children (4-17 yrs), indicated that the prevalence of ADHD was greater among children with vision problems compared with those with normal vision (3). Vision is the ultimate sensory data.
- Maybe, overtraining or repeated exhaustive exercise is just sensation-seeking behavior in order to search for a connection. Chronic stress and exhaustive exercise can disrupt threat and reward systems (25).
- Use of social media can be addictive as it is used to connect with others and manage the impression we make on each other (13).
Not just damage to the somatosensory cortex can cause deviation in normal processing, but also stress and position; which will change afferent information, cortical processing, and thus motor output and behavior. Establishing a normal reference frame is a key factor in connecting. Position sense interpreted from the signals of receptors are measured in a reference frame that can be modified by learning (4). Changes in sensory perception via changes to motor commands, sensory changes, or the two in combination and result in recalibration and reorientation of an individual’s reference frame. How can you do this? It is all just sensory. Connect them to their environment. Use anatomical references (afferent data for brain to know location in space) to create a perceptual feeling; esthesia is the perceptual feeling one has when the sensation of a reference is felt. We need to be able to find and feel the ground or else we will always be searching for it with compensational patterns and behaviors. If you cannot find and feel the ground, you will seek to impinge in order to know you are stable and are grounded. Create sensation, awareness, mindfulness.
The goal is to provide ground and spatial references to allow the brain to know where the body is in space, THEN slowly and progressively take away references to increase difficulty and challenge. Reference centers are specific areas on the body that provide the ability to find stability through afferent information. If an individual can find and feel a reference center, their brain has more information about where they are in space. Progression is dictated by the removal of reference centers. The body just needs information about where it is in space to feel safe breathing, standing and moving. Can you find and feel? Can we rest and relax? Can we make connections? Can we be mindful enough to appreciate those connections?
Figure 4. Providing a right pad for arch support (in footwear) brings the floor to the athlete. It provides a reference they are missing. [If you brought the arch to the floor, it may be at a fault as it would negatively affect the kinetic chain]…OR YOU CAN …Figure 5. Providing a left pad (thicker) for foot arch pushes athlete onto their lateral calcaneus, shifting them to their left side (helping to reestablish reference frame). This is just ONE example of establishing reference centers. This is not permanent, it is just helping them with what they don’t have aka their left side. Finding and feeling feet arches provides inhibition of adductors, while finding and feeling heels provides activation of glutes.
We all want to connect on a human level, but we should also consider connection at the quantum and cosmic level. An eighteenth century German philosopher named Immanual Kant stated that knowledge has three components: appearance, reality, and theory. Appearance is our direct sensory experience of natural phenomena or how we fulfill our desire to understand (using physiology and biology). The world is experienced in drastically different ways for every human being. Reality is what is behind all phenomena and theory consists of human concepts that attempt to mirror both appearance and reality. Physicists work to provide a single metaphor for how the universe actually works, however human beings will never experience reality or theory.
“In order to understand everything, you have to understand the theory of everything” – Dr. Pat Davidson
Sensory experience, as explored above, is human beings attempting to explain and understand how we interact with our environment via sensory (afferent) and motor (efferent) connections within the brain. However, in reality maybe we connect with our environment and each other through a quantum field of energy that transmits light, energy, frequencies, and vibrations. Maybe, all human beings are just a coalescence of energy, in a field of energy, connected to every other coalescence of energy. Maybe, providing someone with a shoe insole for arch support or reference centers changes an individual’s connection with their environment by allowing them to exchange information with quantum fields; helping them change/create their own perception/appearance of the world/universe. Just Maybe…
“Maybe all particles that manifest as electrons, protons, and neutrons are just strings of energy vibrating at different frequencies… and we sense these frequencies as different particles” – Dr. Neil DeGrasse Tyson
It’s all just sensory. More information is efficient performance. Sensory is sports performance. References 26-10000: Hruska, Ron. Postural Restoration Institute (PRI). Postural Restoration, Myokinematic Restoration, Pelvis Restoration, and Impingement and Instability Courses and Instructors. Thank you for providing me with the ability to even TRY to understand. The CONCEPTS that I have learned have made me a better strength and conditioning coach.
This article was written after working with an athlete that I did NOT understand from a movement and impingement perspective. I am thankful for not understanding and for the ability to ATTEMPT to understand. Attempting to understand lead me into ideas, concepts, and thoughts that I am grateful for. Thank you to that athlete that made me better.
About the Author: Dr. Michelle Boland
– Strength and Conditioning Coach at Northeastern University (Boston, MA)
– PhD. Exercise Physiology, Springfield College
– M.S. Strength and Conditioning, Springfield College
– B.S. Nutrition, Keene State College
– Follow on Instagram: mboland18
– Visit: www.michelleboland-training.com