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Subclinical Recurrent Neck Pain and its Treatment Impacts Motor Training-induced Plasticity of the Cerebellum and Motor Cortex

By |March 3, 2018|Subluxation|

Subclinical Recurrent Neck Pain and its Treatment Impacts Motor Training-induced Plasticity of the Cerebellum and Motor Cortex

The Chiro.Org Blog

SOURCE:   PLoS One. 2018 (Feb 28); 13 (2): e0193413

Julianne K. Baarbé, Paul Yielder, Heidi Haavik, Michael W. R. Holmes, Bernadette Ann Murphy

Division of Neurology,
Krembil Research Institute,
University Health Network,
Toronto, Ontario, Canada.

The cerebellum processes pain inputs and is important for motor learning. Yet, how the cerebellum interacts with the motor cortex in individuals with recurrent pain is not clear. Functional connectivity between the cerebellum and motor cortex can be measured by a twin coil transcranial magnetic stimulation technique in which stimulation is applied to the cerebellum prior to stimulation over the motor cortex, which inhibits motor evoked potentials (MEPs) produced by motor cortex stimulation alone, called cerebellar inhibition (CBI). Healthy individuals without pain have been shown to demonstrate reduced CBI following motor acquisition. We hypothesized that CBI would not reduce to the same extent in those with mild-recurrent neck pain following the same motor acquisition task. We further hypothesized that a common treatment for neck pain (spinal manipulation) would restore reduced CBI following motor acquisition. Motor acquisition involved typing an eight-letter sequence of the letters Z,P,D,F with the right index finger. Twenty-seven neck pain participants received spinal manipulation (14 participants, 18–27 years) or sham control (13 participants, 19–24 years). Twelve healthy controls (20–27 years) also participated. Participants had CBI measured; they completed manipulation or sham control followed by motor acquisition; and then had CBI re-measured. Following motor acquisition, neck pain sham controls remained inhibited (58 ± 33% of test MEP) vs. healthy controls who disinhibited (98 ± 49% of test MEP, P<0.001), while the spinal manipulation group facilitated (146 ± 95% of test MEP, P<0.001). Greater inhibition in neck pain sham vs. healthy control groups suggests that neck pain may change cerebellar-motor cortex interaction. The change to facilitation suggests that spinal manipulation may reverse inhibitory effects of neck pain.

From the Full-Text Article:


The neck is linked biomechanically and neurologically to the upper limbs, and yet, we know little about the mechanisms by which altered sensory feedback from the neck due to pain, fatigue, and altered posture affects upper limb sensorimotor integration (SMI) and the ability to learn new motor skills. [1–4] Motor learning refers to the acquisition or improvement of a motor skill with practice. [5] The cerebellum is known to undergo neuroplastic changes following motor training and is responsible for modulation of motor circuitry. [6] It plays a key role in processing sensory input to predict sensory consequences of movement for online motor corrections as well as for updating body schema in feedforward models of motor control [7], which allows corrections to be made prior to the time physically needed to receive sensory feedback from distal sources such as the hand. [8]

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Neural Responses to the Mechanical Characteristics of High Velocity, Low Amplitude Spinal Manipulation: Effect of Specific Contact Site

By |June 23, 2017|Subluxation|

Neural Responses to the Mechanical Characteristics of High Velocity, Low Amplitude Spinal Manipulation: Effect of Specific Contact Site

The Chiro.Org Blog

SOURCE:   Man Ther. 2015 (Dec); 20 (6): 797–804

William R. Reed, Cynthia R. Long,
Gregory N. Kawchuk, and Joel G. Pickar

Palmer Center for Chiropractic Research,
Davenport, IA, USA.

BACKGROUND:   Systematic investigations are needed identifying how variability in the biomechanical characteristics of spinal manipulation affects physiological responses. Such knowledge may inform future clinical practice and research study design.

OBJECTIVE:   To determine how contact site for high velocity, low amplitude spinal manipulation (HVLA-SM) affects sensory input to the central nervous system.

DESIGN:   HVLA-SM was applied to 4 specific anatomic locations using a no-HVLA-SM control at each location randomized in an 8×8 Latin square design in an animal model.

METHODS:   Neural activity from muscle spindles in the multifidus and longissimus muscles were recorded from L6 dorsal rootlets in 16 anesthetized cats. A posterior to anterior HVLA-SM was applied through the intact skin overlying the L6 spinous process, lamina, inferior articular process and L7 spinous process. HVLA-SMs were preceded and followed by simulated spinal movement applied to the L6 vertebra. Change in mean instantaneous discharge frequency (ΔMIF) was determined during the thrust and the simulated spinal movement.

RESULTS:   All contact sites increased L6 muscle spindle discharge during the thrust. Contact at all L6 sites significantly increased spindle discharge more than at the L7 site when recording at L6. There were no differences between L6 contact sites. For simulated movement, the L6 contact sites but not the L7 contact site significantly decreased L6 spindle responses to a change in vertebral position but not to movement to that position.

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Altered Central Integration of Dual Somatosensory InputAfter Cervical Spine Manipulation

By |October 9, 2015|Chiropractic Care, Spinal Manipulation, Subluxation|

Altered Central Integration of Dual Somatosensory Input After Cervical Spine Manipulation

The Chiro.Org Blog

SOURCE:   J Manipulative Physiol Ther. 2010 (Mar);   33 (3):   178–188 ~ FULL TEXT

Heidi Haavik Taylor, PhD, BSc, Bernadette Murphy, PhD, DC

Director of Research,
New Zealand College of Chiropractic,
Auckland, New Zealand.

OBJECTIVE:   The aim of the current study was to investigate changes in the intrinsic inhibitory interactions within the somatosensory system subsequent to a session of spinal manipulation of dysfunctional cervical joints.

METHOD:   Dual peripheral nerve stimulation somatosensory evoked potential (SEP) ratio technique was used in 13 subjects with a history of reoccurring neck stiffness and/or neck pain but no acute symptoms at the time of the study. Somatosensory evoked potentials were recorded after median and ulnar nerve stimulation at the wrist (1 millisecond square wave pulse, 2.47 Hz, 1 x motor threshold). The SEP ratios were calculated for the N9, N11, N13, P14-18, N20-P25, and P22-N30 peak complexes from SEP amplitudes obtained from simultaneous median and ulnar (MU) stimulation divided by the arithmetic sum of SEPs obtained from individual stimulation of the median (M) and ulnar (U) nerves.

RESULTS:   There was a significant decrease in the MU/M + U ratio for the cortical P22-N30 SEP component after chiropractic manipulation of the cervical spine. The P22-N30 cortical ratio change appears to be due to an increased ability to suppress the dual input as there was also a significant decrease in the amplitude of the MU recordings for the same cortical SEP peak (P22-N30) after the manipulations. No changes were observed after a control intervention.

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Spinal Manipulative Therapy and Somatosensory Activation

By |March 13, 2015|Spinal Manipulation, Subluxation|

Spinal Manipulative Therapy and
Somatosensory Activation

The Chiro.Org Blog

SOURCE:   J Electromyogr Kinesiol. 2012 (Oct);   22 (5):   785–794

Joel G Pickar, DC PhD and Philip S Bolton, DC PhD

Palmer Center for Chiropractic Research,
Palmer College of Chiropractic,
Davenport, IA, USA.

Manually-applied movement and mobilization of body parts as a healing activity has been used for centuries. A relatively high velocity, low amplitude force applied to the vertebral column with therapeutic intent, referred to as spinal manipulative therapy (SMT), is one such activity. It is most commonly used by chiropractors, but other healthcare practitioners including osteopaths and physiotherapists also perform SMT. The mechanisms responsible for the therapeutic effects of SMT remain unclear. Early theories proposed that the nervous system mediates the effects of SMT. The goal of this article is to briefly update our knowledge regarding several physical characteristics of an applied SMT, and review what is known about the signaling characteristics of sensory neurons innervating the vertebral column in response to spinal manipulation. Based upon the experimental literature, we propose that SMT may produce a sustained change in the synaptic efficacy of central neurons by evoking a high frequency, bursting discharge from several types of dynamically-sensitive, mechanosensitive paraspinal primary afferent neurons.

From the FULL TEXT Article:


Manually-applied movement and mobilisation of body parts as a healing activity has been used for centuries (Wiese & Callender, 2005). A relatively high velocity, low amplitude force applied to the vertebral column with therapeutic intent, referred to as spinal manipulative therapy (SMT), is one such activity. It is most commonly used by chiropractors, but other healthcare practitioners including osteopaths and physiotherapists use it as well. Although SMT has been advocated for a wide range of health problems (Ernst & Gilbey, 2010), currently available best evidence suggests it has a therapeutic effect on people suffering some forms of acute neck and back pain particularly when it is used in combination with other therapies (Brønfort et al, 2004; Brønfort et al, 2010; Dagenais et al, 2010; Miller et al 2010; Walker et al 2010; Lau et al 2011). Its effect on chronic low back pain is less clear (Rubinstein et al 2011; Walker et al 2010).

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Specific Potentialities of the Subluxation Complex

By |May 27, 2013|Cervical Spine, Diagnosis, Education, Subluxation|

Specific Potentialities of the Subluxation Complex

The Chiro.Org Blog

We would all like to thank Dr. Richard C. Schafer, DC, PhD, FICC for his lifetime commitment to the profession. In the future we will continue to add materials from RC’s copyrighted books for your use.

This is Chapter 7 from RC’s best-selling book:

“Basic Principles of Chiropractic Neuroscience”

These materials are provided as a service to our profession. There is no charge for individuals to copy and file these materials. However, they cannot be sold or used in any group or commercial venture without written permission from ACAPress.

Chapter 7: Specific Potentialities of the Subluxation Complex

This chapter describes the primary neurologic implications of subluxation syndromes, either as a primary factor or secondary to trauma or pathology, within the cervical spine, thoracic spine, lumbar spine, and pelvic articulations.


Studies reported by Drum, Hargrave-Wilson, Kunert, Burke, Gayral/Neuwirth, and others have shown that a subluxation complex, often leading to spondylosis, can effect a wide variety of disturbances that may appear to be disrelated on the surface. Most of the remote effects can be grouped under the general classifications of nerve root neuropathy, basilar venous congestion, cervical autonomic disturbances, CSF pressure and flow disturbances, axoplasmic flow blocks, irritation of the recurrent meningeal nerve, the Barre-Lieou syndrome, and/or the vertebral artery syndrome.

This chapter describes many causes for and effects of a spinal subluxation complex. In clinical practice, however, causes and effects are rarely found as isolated entities. Several factors will usually be involved and superimposed on each other.

Innervation of the Spinal Dura

It has long been known that the spinal dura mater has an intrinsic nerve supply. Spinal meningeal rami are derived from gray communicating rami and spinal nerves. The spinal nerves contribute sensory fibers to the meningeal rami. Several meningeal rami enter each IVF, and most are located anteriorly to the sensory ganglia within the IVF.

Bridge found that these intrinsic nerve fibers reach the anterior surface of the dura by three main courses. Here the nerves divide into ascending and usually longer descending filaments that run longitudinally and parallel on the dural surface, and a considerable amount of nerve overlaps from adjacent segments. Finer filaments penetrate the dural substance where they subdivide.

Kimmel reported that most of these fibers penetrate the dura near the midline, while others enter laterally near the exiting spinal nerve roots. At each segment level, two or three nerves enter the spinal dura mater and contain only small nerve fibers. In contrast, Edgar/Nundy could determine no definitive nerve endings, but the nerves could be traced to the posterior aspect of the spinal dura. These observations help to clarify the wide distribution of back pain that is often found following protrusion of a single IVD.

      Cervical Dura Attachments

Sunderland states that the nerve sheaths in the cervical region are not firmly attached to their respective foramina. Only the C4 C6 cervical nerves have a strong attachment to the vertebral column, and this is to the gutter of the vertebral transverse process. He believes that these observations have relevance to any local lesion that may fix, deform, or otherwise affect the nerve and its roots to the point of interfering with their function, and they also may be important to traction injuries of nerve roots.


The Subluxation – Historical Perspectives Part II

By |September 30, 2012|Chiropractic Care, Subluxation|

The Subluxation – Historical Perspectives Part II

The Chiro.Org Blog

SOURCE:   Chiropractic Journal of Australia 2009 (Dec); 39 (4): 143–150

Rolf E. Peters, DC, MCSc, FICC, FACC, FPAC
Chiropractic Journal of Australia

Thanks to Dr. Rolf Peters, editor of the Chiropractic Journal of Australia for permission to republish this Full Text article, exclusively at Chiro.Org!

Subluxation is a term that has been used by the chiropractic profession since its early days. The term, meaning less than a luxation, has been used for millennia, similarly so has manipulation been the preferred intervention to overcome this problem.

This paper reviews some of the early uses of subluxation and manipulation identifying highlights, to help the reader appreciate that subluxation and manipulation, both spinal and general, are as old as civilisation itself.



D.D. Palmer stated that he manipulated the spine of Harvey Lillard on 18 September 1895 and restored his hearing after 17 years of deafness, and shortly thereafter gave immediate relief in a case of heart trouble. [1] With the advice of a patient, the Reverend Samuel Weed, they coined the word Chiropractic from the Greek words chiro and praxis, meaning done by hand on 14 January 1896. [2]

In 1905 D.D., with reference to himself in the third person, stated that

…he does not, nor ever has claimed that vertebrae may be displaced and replaced. He, however, is the first to draw the attention of the public to the difference between a complete luxation known to the medical world as such, and a subluxation as known to the chiropractor as a displacement of the articular processes.

He was the first to write lengthy articles, setting forth that 90 to 95 per cent of all diseases were caused by subluxation of vertebrae, and today no other person has placed such statements in the hands of the public unless copied from those written by D.D. Palmer

He was the first person to adjust, replace vertebrae by the unique method known as Chiropractic, using the spinous and transverse processes as handles.[3] (Emphasis added)

But, what are the facts?

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