Michael M. Patterson

Spinal Fixation: Long-Term Alterations in Spinal Reflex Excitability with Altered or Sustained Sensory Inputs

The mammalian spinal cord has long been known to contain a rich variety of reflex pathways, in addition to providing the pathways for transmission of neural signals to and from the body and the higher nervous system. For many years, these reflexes were assumed to be essentially unchanging, hard-wired entities that provided the underpinnings for response to stimuli. Sherrington (1905)) noted that reflex activity could be increased or decreased with activation, but that these effects were transient. In the 1960s and 1970s work by investigators such as Thompson (e.g., Thompson and Spencer, 1966) began to study the ability of sensory inputs to the reflex pathways to alter reflex activity. Soon, the work of Kandel (e.g., Carew, Pinsker and Kandel, 1972) and his associates showed in Aplysia that reflex alterations could have a longer-lasting component. This led to the realization that in the mammalian cord there could be longer lasting aspect of reflex excitability alterations. However, this fact had been shown to occur with learning paradigms much earlier. Shurrager and his colleagues (e.g., Shurrager and Culler, 1940) had demonstrated that spinal reflexes responded with increased activity to a classical conditioning paradigm and that the increased responsiveness lasted for hours in spinalized animals. While controversial, these data set the stage for increased interest in the possibility that spinal reflexes were not simply relatively unchanging neural networks left over from the distant past and superceded by increasing encephalization of function in higher animals.

Basic Mechanisms of Osteopathic Manipulative Treatment: A Must Read.

work flows and builds on itself to finally tell a story. One or 2 studies may be interesting or even groundbreaking, but a good research program will produce a body of work that paints an ongoing and internally consistent picture. The student of research would be well advised to look at this research program as a model of how to develop a true research program and follow it to a logical conclusion. Standley’s interest in fibroblasts, the fundamental cells in many different tissues, such as muscle, fascia, and other soft tissues, led to his interest in how they respond to mechanical stress and strain and how they might respond to OMT, especially counterstrain and myofascial release. The model fibroblast preparation Standley developed and has used in many of his studies involves seeding fibroblast cells onto elastic substrates and letting the cells grow and attach to the substrate. Forces can then be applied to the cells by stretching the membrane in various ways to stress or injure the fibroblasts. His work has shown that fibroblasts respond differently to various strain patterns, secreting various anti-inflammatory chemicals and growth factors, with implications for wound healing and muscle repair, among other physiologic processes. By simulating OMT-patterned movements on layers of fibroblasts, Standley has shown that detrimental responses of fibroblasts can be altered or reversed with the OMT simulations. Various combinations of forces and OMT or no OMT allow for wellcontrolled observations of the effects produced. He has gone on to develop a 3-dimensional fibroblast preparation called a bioengineered tendon that can be stretched or pierced to look at the response to these stressors and the effects of OMT on these injuries. In one example, he showed that direct myofascial release was most effective in reversing strain-induced injuries when it was of low magnitude for a longer duration.8 Thus, these preparations have the potential not only to show the effectiveness of OMT simulations, but to provide Basic Mechanisms of Osteopathic Manipulative Treatment: A Must Read