Associate Professor of Biology and Neuroscience
Director of Neuroscience Program
Druckenmiller Hall - 130E
Examination of the molecular control of neuronal structure and function. Topics include the molecular basis of neuronal excitability, the factors involved in chemical and contact-mediated neuronal communication, and the complex molecular control of developing and regenerating nervous systems. In the spring of 2017, students enrolling in Molecular Neurobiology have two choices for the lab. They may enroll in a traditional weekly lab (LAB 2 offered on Tuesday), or enroll in an intensive 8-day lab (LAB 1) to be held during the first half of spring break at Mount Desert Island Biological Laboratory, in Salisbury Cove, Maine. Participants will stay in dorms and focus solely on lab work for the duration of the lab. This experience will completely replace weekly labs. The focus of the lab will be learning Bioinformatics and running quantitative-PCR experiments. All expenses (transportation, room, and board) are covered. Signing up for either lab section (weekly Tuesday labs--CRN# 20059, or the intensive 8 days over spring break --CRN# 20058) completes the laboratory requirement for the course.
The Horch lab uses the cricket model system to examine the molecular neurobiological basis of a number of areas including regeneration, behavior, and development. Mainly, the lab will focus on the regeneration of interneurons in the auditory system of the cricket. Removing one ear induces auditory interneurons to sprout new dendrites, grow abnormally across the mid-line, and form synapses with intact auditory neurons from the opposite ear, both in developing as well as adult crickets. This is one of the most elegant and complex examples of neuronal regeneration known. Techniques such as dextran backfills, immunohistochemistry, and confocal microscopy will be used to understand the molecular cues involved in this phenomenon. Other projects include examining the role of octopamine on male cricket aggression and attempting to create transgenic crickets in order to examine the development of individual neurons.
Horch, H.W., Sheldon, E., Cutting, C.C., Williams, C.R., Riker, D.M., Peckler, H.R., and Sangal, R.B. 2011. Bilateral consequences of chronic unilateral denervation in the auditory system of the cricket Gryllus bimaculatus. Developmental Neuroscience, 33: 21-37.
Horch, H.W., McCarthy, S.S., Johansen, S.L., and Harris, J.M. 2009. Differential gene expression during compensatory sprouting of dendrites in the auditory system of the cricket Gryllus bimaculatus. Insect Molecular Biology, 18: 483-496.
Maynard, K.M., McCarthy, S.S., Sheldon, E., Horch, H.W. 2007. Developmental and adult expression of sempahorin 2a in the cricket Gryllus bimaculatus. Journal of Comparative Neurology. 503: 169-181.
Horch, H.W. 2004. Local effects of BDNF on dendritic growth. Reviews in the Neurosciences, 15: 116-129.
Horch, H.W. and Katz, L.C. 2002. BDNF release from single cells elicits local dendritic growth in nearby neurons. Nature Neuroscience, 5: 1177-1184.
Horch, H.W., Kruttgen, A., Portbury, S.D, and Katz, L.C. 1999. Destabilization of cortical dendrites and spines by BDNF. Neuron, 23: 353-364.
Horch, H.W., and Sargent, P.B. 1996. Effects of denervation on acetylcholine receptor clusters on frog cardiac ganglion neurons as revealed by quantitative laser scanning confocal microscopy. J. Neurosci. 16(5): 1720-1729.
Horch, H.W., and Sargent, P.B. 1996. Synaptic and extrasynaptic distribution of two distinct populations of nicotinic acetylcholine receptor clusters in the frog cardiac ganglion. J. Neurocytol. 25: 67-77.
Horch, H.W., and Sargent, P.B. 1995. Perisynaptic surface distribution of multiple classes of nicotinic acetylcholine receptors on neurons in the chicken ciliary ganglion. J. Neurosci. 15(12): 7778-7795.