Neuromuscular control and sensory feedback of fish fins

INVESTIGATOR: Anabela Maia, Rhode Island College
MENTOR: Elizabeth Brainerd, Brown University


ABSTRACT: Problems with motor control strongly impact quality of life. Lack of control and the inability to adequate perceive sensory information and adjust muscle contraction are at the source of many pathologies including Parkinson, Multiple Sclerosis as well in a variety of patients recovering from stroke and central nervous system injuries. Stability specifically is highly affected in many patients with reduced sensation in lower limb extremities and can lead to falls and further health deterioration. Similar problems are also apparent in prosthetic devices where lack of control and feedback renders prosthetics mostly cosmetic. This project can inform the development of sensors for prosthetic users as well as for patients with neuropathies. Fish are a good model to study how the lack of sensory information can affect recovery from the loss of stability. In fish, stability is achieved by activation of muscles at the base of the fins, including the spiny dorsal fin of bony fishes, which functions much like a keel in a sailboat. This system is particularly well suited to investigate the neuromuscular control since the rays of the spiny dorsal fin have a simple structure and are activated mostly by one set of muscles. In addition, perturbations to stability are easily accomplished by introducing turbulence near the fish. This project will look at how body posture is controlled in a fish model after a perturbation in the absence of motor control by injection of a muscle relaxant, in the absence of sensory information through injection of an anesthetic or under control conditions, by injection of a saline solution. We will investigate what perturbations are the most nefarious to the model organism and how does muscle function respond immediately after the first perturbation and after repeated stimuli by recording muscle activity through small electrodes and changes in body position through high-speed video and accelerometry. We will also look at the neuromuscular anatomy to determine innervation and feedback loops.

HUMAN HEALTH RELEVANCE: Understanding neuromuscular control can help improve the life quality of individuals with impaired sensation, motor control and missing limbs. The results of this project can be applied to: 1) develop targeted therapies for patients with impaired sensation or motor control that capitalize on the response to repeated stimuli; 2) develop electrode implants to mimic the feedback loops for more responsive prosthetic devices; 3) offer insight to clinical research into neuromuscular regeneration.