Susan Harkema, PhD
Khalid Jones, MS
Sohara Perez, BS
The Neurophysiology and Neuroimaging Core takes a comprehensive approach to the evaluation of the central nervous system, and specifically the components that are responsible for producing movements. We are interested in understanding how different components of the nervous system respond to a spinal cord injury, and how they may adapt with various interventions such as locomotor training. The techniques that we utilize are highly specialized to provide information that can be used to further our understanding of the human central nervous system and to aid in the development and assessment of novel intervention therapies.
- Functional Neurophysiological Assessment (FNPA): Sensors placed on a combination of muscles in the arms, legs, trunk, or neck give measurements on how the individual’s neurological system is functioning to control movement when the participant is asked to perform a variety of tasks
- Acoustic Startle reflex (ASR): This assessment is a recording of the muscle reflexes when the participant is startled by loud unexpected sounds at unknown intervals using headphones in a quiet room. These responses give us insight to the strength of the reticulospinal pathway./
- Galvanic Vestibular Stimulation (GVS): a small electrical current is sent though one side of the neck to the other to stimulate the balance system while the participant is sitting, standing, or laying down; this is an assessment of the vestibulospinal pathway.
- Propriospinal Pathway Stimulation (PS): Electrical or magnetic stimulation is applied to several nerves and the responses are measured in multiple muscles. The goal of this assessment is to test inter-limb muscle reflexes and therefore the strength of the propriospinal pathway which can serve as an alternate pathway for motor commands .
- Multisegmental Motor Responses (MMR): Electrical stimulation will be sent though a pad on the midline of the back during different and muscle responses will be recorded through sensors placed over the skin. This is an assessment of the excitability of the spinal cord.
- Transcranial Magnetic Stimulation (TMS): Responses of the nerve pathways running from the brain to the spinal cord is evaluated using magnetic stimulation to the brain. Additionally, TMS can be used to assess excitability of cortical circuits.
- Spinal Magnetic Stimulation: Magnetic stimulation is applied to the back along the spine and sensors on the skin record muscle activity in the legs. The assessment is to determine if magnetic stimulation is effective in reaching consistent activation of spinal circuitry.
- Hoffman Reflex (H-Reflex): Electrical stimulation is applied to peripheral nerves in the body and sensors on the skin will measure the responses of the muscles in response to stimulation. This is an assessment of the excitability of the spinal cord.
- Antidromic Motoneuron Activation (F waves): Electrical stimulation is applied to peripheral nerves and responses in distal muscles are recorded. This measurement gives insight to the excitability of the neurons that control your muscles (motoneurons).
- Somatosensory Evoked Potential (SSEP): the activity of the brain is recorded during electrical stimulation to the wrist and ankles. This is an assessment of the ability of the brain, spinal cord and sensory cortex to conduct signals in response to stimuli.
- Evoked Response Potential (ERP): Similar to the SSEP assessment, this is a more in-depth look into the sensory cortex part of the brain using a rage of 5-64 sensors placed along the scalp and/or jaw. There will be continuous recording of brain wave (EEF) data throughout the experiments as well as sensors on the upper and lower back and behind the knee.
- Sympathetic Skin Responses (SSR): low amounts of electrical stimulation is applied to nerves in the hands and feet using electrodes placed on the skin, sensors measure sympathetic skin responses.
- Spinal Cord Magnetic Resonance Imaging (scMRI): Images of the spinal cord are taken using MRI scans and will be analyzed at various levels of the cord for measurements of flow of the fluid in spinal cord, and flow in the arteries and veins.
- Functional Magnetic Resonance Imaging (fMRI): MRI scanning technology is used to generate images of the brain using magnetic properties of blood.
- Diffusion Tensor Imaging (DTI): MRI scans of the brain and spinal cord generate images that are used to measure amounts of water spread throughout damaged and undamaged tissue, the assessment also provides information about the flow and pressure of fluid with in the brain and spinal cord
We employ a “Discovery-to-Recovery” approach and work closely across disciplines to expand knowledge and bring innovative treatments to practice so that individuals with spinal cord injuries can experience their own personal Victory Over Paralysis. Our work is published in leading scientific journals.
The human central nervous system has multiple components that contribute to the generation of movements. After a SCI, the efficacy of each of these components is affected and is unique to each injury. The assessments that we perform allow us to gain insight into each individual’s specific neurophysiological state. The sensitivity of our assessments also allows us to capture information that clinical assessments cannot. This information is leading to a greater understanding of the central nervous system, and aids in the development and assessment of novel neuromodulatory and rehabilitation interventions.
Metabolic, Neuromuscular, and Skeletal
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Movement Performance and Locomotor Recovery
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Movement Performance and Locomotor Recovery Clinic