We are studying the neuronal mechanisms responsible for establishing circuitry underlying the local bending response in the medicinal leech. Local bending replaces an embryonic behavior, circumferential indentation, during the time of initial chemical synaptogenesis in leech embryos. We found that the electrical connections among the motor neurons are established first, about 5% of embryonic ti...

The oscillations that underlie swimming movements in the leech arise from a series of identified concatenated circuits within the ventral nerve cord. In the intact nerve cord, ascending and descending intersegmental interactions via axons within the lateral connectives function both to generate robust oscillations throughout the cord and to establish an anterior-to-posterior phase delay among s...

The local bend is a directed behavior produced by the leech, Hirudo medicinalis, in response to a light touch. Contraction of longitudinal muscles near the touched location results in a bend directed away from the stimulus. We quantify the relationship between the location of touch around the body perimeter and the behavioral output by using video analysis, muscle tension measurements, and elec...

Experiments were performed to determine the role of acetylcholine (ACh) in neuromuscular transmission in the heart of the leech Hirudo medicinalis. Superfused or iontophoretically applied ACh rapidly depolarized both isolated heart muscle cells and muscle cells in isolated hearts in a dose-dependent manner. the depolarization was associated with a conductance increase of the muscle membrane tha...

Patient: Female, 42 Final Diagnosis: Leech bite Symptoms: - Medication: - Clinical Procedure: - Specialty: Infectious diseases. OBJECTIVE Unusual clinical course. BACKGROUND Hirudo medicinalis (H. Medicinalis), also referred to as the medical leech, not only has been used by alternative medicine s...

In the absence of external stimuli, animals explore the environment by performing irregular movements, but the neuronal mechanisms underlying this arrhythmic motion are largely unknown. In this paper, we studied the relationship between the spontaneous neuronal activity in the leech (Hirudo medicinalis) and its behavior. We analyzed the electrical activity of isolated ganglia, chains of two con...