Behavioral Neuroscience, Leech Circuitry
USD Department of Biology
Behavioral Neuroscience
Summers 		Leech Shortening
Sensory Stimulation of Shortening
S&R Sensitization
Learning
Motor Efferents
Neuromuscular Function
Integration 		Glu
5-HT
ACh
Leech figures
Shortening Neurocircuitry
end     Acronyms/Abbreviations
Neurocircuitry of the Leech, subclass Hirudinea    back to Behavior Lecture



Hirudinea Nervous System:
1) Segmental Organization
Comparison of Leech and Human Nervous Systems
Similar in segmented functional compartments to all vertebrates
1.5) Chain of ganblia


2) ganglion
Leech segmental ganglion

3) Electrical Synapses

4) Identified Neurons
Each Neuron is identified for a specific purpose Ventral Aspect T, P, N, R, S labelled 
left = anterior Dorsal View (left figure)                                                               Ventral View (right figure)


T cells = touch mechanoreceptors
Somatosensory cells

P cells = pressure mechanoreceptors
Pressure cells

N cells = Nociception = Pain cells
Pain Receptors 

                       Ventral View (left figure)                                                               Dorsal View (right figure)

S cells = interneurons
interneurons

Retzius Cells
large 5-HT cells
Motor Neurons = L cells efferent ACh neurons ending at neuromuscular junctions
motor neurons


Action Potenial

5) Ding Vm = membrane potential

Na+ in first, then K+ out
Na current can be augmented by Ca

Afterhypolarization