Research

Current lab projects fall within two broad areas, spinal cord network development and spinal cord network control.

Spinal cord network development

One approach we are taking to analyze spinal cord network development is to analyze the accordion class of behavioral mutants. Beginning around 22 hours post-fertilization, wild-type embryos respond to touch with alternating tail coils (view movie - 2MB). In contrast, accordion mutants respond to touch by compressing along the nose-tail axis similar to the accordion musical instrument (view movie - 3.8MB ). Since spinal cord networks coordinate alternating tail flips, some of these mutants can provide insight into the genes and cellular events required for spinal cord network assembly. For example, in previous studies, we and others have identified a novel glycine receptor beta subunit gene, mutated in bandoneon mutants, that is required for normal spinal cord network function. Abnormal muscle relaxation or neuromuscular synapse regulation can also generate accordion behavior, and we and others have also found that some of the accordion class mutants have neuromuscular synapse or muscle defects. These mutants can serve as useful tools to analyze muscle function, however we are primarily interested in analyzing accordion class mutants to understand spinal cord network development.

Spinal cord network control

To investigate spinal cord network control, we are analyzing another class of behavioral mutants, the crazyfish class. Mutants from this class first display abnormal behavior later than accordion class mutants. After 2 days post-fertilization, wild-type larvae respond to touch by performing an escape response. The escape response consists of a large, C-like, body bend away from the touch stimulus, followed by smaller, alternating tail flips to swim away from the perceived threat. Crazyfish class mutants perform an initial C-like body bend, however subsequent tail flips are interrupted by additional C-like bends. Groups of neurons in the hindbrain regulate spinal cord networks to produce the C-like bends of an escape response, therefore crazyfish class mutants may identify genes and cellular mechanisms important for both hindbrain and spinal cord function. Since the inhibitory neurotransmitters glycine and GABA are important for both hindbrain and spinal cord function, we are also examining the development of these inhibitory networks.

Potential projects

A variety of projects is available to study spinal cord development or control for highly motivated undergraduate students, graduate students, and post-doctoral fellows. Please contact gbdownes@bio.umass.edu if you are interested in joining us.