Browsing by Subject "Motor neuron"

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The impact of foam rolling on explosive strength and excitability of the motor neuron pool
(2013-08) Abels, Kristin Marie; Abraham, Lawrence D.
To assess acute performance-related effects of foam rolling, this study investigated the immediate effects of a standard foam rolling protocol on explosive strength of the plantarflexors and alpha motor neuron excitability in the soleus. Explosive strength was measured via vertical jump height (JUMP) and the Reactive Strength Index (RSI) obtained from a single leg drop jump. Alpha motor neuron excitability was measured by H reflex amplitude as H wave to M wave ratio (HM) obtained from the soleus muscle. JUMP and RSI measures were analyzed from nineteen subjects (12 male, 7 female) HM data were analyzed from 15 subjects (9 male, 6 female). Subjects attended one day of practice and instruction for the single leg drop jump and one day for data collection. One leg was randomly assigned to be the test leg (FL) and the other as the control (NL). The reported dominant leg and gender were also recorded for each subject. Subjects performed two single leg drop jumps per leg from a box height of 30 cm and then 10 soleus H reflexes were obtained. The intervention, which followed standard professional guidelines, consisted of 2.5 minutes of foam rolling for the FL and rest for the NL, followed by a 5 minute warm up on a cycle ergometer. The best jump and the average HM ratio were chosen for analysis. For each variable a post/pre ratio was calculated for statistical analysis. A 2x2x2 factor ANOVA with repeated measures on both factors was used for each variable. Analysis revealed no statistically significant differences for any of the variables, either as main effects or any of the interaction effects. Subjects trended towards a slightly larger post-intervention decrease in JUMP and RSI for the FL than the NL but this was not significant. It was concluded that a 2.5 minute intervention of foam rolling had no acute effect on explosive strength of the plantarflexors or alpha motor neuron excitability of the soleus.
Neuronal activity in motor neuron and V2a interneuron cultures
(2022-08-03) Somavarapu, Rachel; Sakiyama-Elbert, Shelly E.; Wang, Huiliang (Evan)
The consequences of a spinal cord injury can include paralysis, and loss of motor function, sensory function, and proprioception. Furthermore, spinal cord injuries are often associated with potentially fatal complications, such as pneumonia or sepsis. Spinal cord injuries can take a negative toll on a patient’s life by causing discomfort or by hindering them from living a normal life. Current treatments, such as rehabilitative therapy, electrical spinal cord stimulation, and spinal cord surgery are not effective in treating this condition. However, studying the behavior of cultured neurons in-vitro can help determine what combination of cells are most beneficial for spinal cord transplantation or targeting regeneration of endogenous neural populations. The goal of this project is to study two types of neurons that are found in the spinal cord, motor neurons and V2a interneurons, and examine how these cells behave when they are cultured separately versus cocultured together. Selectable cell lines containing puromycin N-acetyl-transferase (PAC) under the control of either the Hb9 or Chx10 gene regulatory element were induced and selected to form neurons over a 6 day period. The neurons were plated in multielectrode array (MEA) plates or 24 well plates. Collected data regarding the neural firing rate, burst frequency, number of spikes observed, network inter-spike interval coefficient of variation, and synchrony were analyzed to determine differences in activity between mono- and co-cultures.