 |
||||
|
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
The Journal of Neuroscience, February 15, 2001, 21(4):1401-1412
Non-Associative Learning and Serotonin Induce Similar Bi-Directional Changes in Excitability of a Neuron Critical for Learning in the Medicinal Leech
Brian D. Burrell1, Christie L. Sahley3, and Kenneth J. Muller1, 2 1 Department of Physiology and Biophysics and 2 Neuroscience Program, University of Miami School of Medicine, Miami, Florida 33136, and 3 Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
In studies of the cellular basis of learning, much attention has focused on plasticity in synaptic transmission in terms of transmitter release and the number or responsiveness of neurotransmitter receptors. However, changes in postsynaptic excitability independent of receptors may also play an important role. Changes in excitability of a single interneuron in the leech, the S-cell, were measured during non-associative learning of the whole-body shortening reflex. This interneuron was chosen because it is known to be necessary for sensitization and full dishabituation of the shortening response. During sensitization, S-cell excitability increased, and this enhancement corresponded to facilitation of the shortening reflex and increased S-cell activity during the elicited response. During habituation training, there was a decrement in both the shortening reflex and the elicited S-cell activity, along with decreased S-cell excitability. Conversely, dishabituation facilitated both the shortening response and S-cell activity during shortening, with an accompanying increase in S-cell excitability. Bath application of 1-10 µM serotonin (5HT), a modulatory neurotransmitter that is critical for sensitization, for full dishabituation, and for associative learning, increased S-cell excitability. S-cell excitability also increased after stimulation of the serotonergic Retzius cells. However, focal application of serotonin onto the S-cell soma hyperpolarized the interneuron, and bath application of a lower dose of serotonin (0.1 µM) decreased excitability. The observed changes in postsynaptic excitability appear to contribute to non-associative learning, and modulatory neurotransmitters, such as serotonin, evidently help regulate excitability. Such changes in S-cell excitability may also be relevant for more complex, associative forms of learning.
Key words: leech; serotonin; learning; sensitization; habituation; neuron excitability
Copyright © 2001 Society for Neuroscience 0270-6474/01/2141401-12$05.00/0
This article has been cited by other articles:
A. M. Khan and G. E. Spencer
Novel neural correlates of operant conditioning in normal and differentially reared Lymnaea
J. Exp. Biol., April 1, 2009; 212(7): 922 - 933.
[Abstract] [Full Text] [PDF]
B. D. Burrell and K. M. Crisp
Serotonergic Modulation of Afterhyperpolarization in a Neuron That Contributes to Learning in the Leech
J Neurophysiol, February 1, 2008; 99(2): 605 - 616.
[Abstract] [Full Text] [PDF]
K. M. Crisp and K. A. Mesce
Beyond the central pattern generator: amine modulation of decision-making neural pathways descending from the brain of the medicinal leech
J. Exp. Biol., May 1, 2006; 209(9): 1746 - 1756.
[Abstract] [Full Text] [PDF]
K. M. Crisp and K. J. Muller
A 3-synapse positive feedback loop regulates the excitability of an interneuron critical for sensitization in the leech.
J. Neurosci., March 29, 2006; 26(13): 3524 - 3531.
[Abstract] [Full Text] [PDF]
B. D. Burrell and C. L. Sahley
Serotonin Mediates Learning-Induced Potentiation of Excitability
J Neurophysiol, December 1, 2005; 94(6): 4002 - 4010.
[Abstract] [Full Text] [PDF]
B. L. Moss, A. D. Fuller, C. L. Sahley, and B. D. Burrell
Serotonin Modulates Axo-Axonal Coupling Between Neurons Critical for Learning in the Leech
J Neurophysiol, October 1, 2005; 94(4): 2575 - 2589.
[Abstract] [Full Text] [PDF]
R. Scuri, R. Mozzachiodi, and M. Brunelli
Role for Calcium Signaling and Arachidonic Acid Metabolites in the Activity-Dependent Increase of AHP Amplitude in Leech T Sensory Neurons
J Neurophysiol, August 1, 2005; 94(2): 1066 - 1073.
[Abstract] [Full Text] [PDF]
M. A. Calvino, I. R. Iscla, and L. Szczupak
Selective Serotonin Reuptake Inhibitors Induce Spontaneous Interneuronal Activity in the Leech Nervous System
J Neurophysiol, May 1, 2005; 93(5): 2644 - 2655.
[Abstract] [Full Text] [PDF]
J. Xu, N. Kang, L. Jiang, M. Nedergaard, and J. Kang
Activity-Dependent Long-Term Potentiation of Intrinsic Excitability in Hippocampal CA1 Pyramidal Neurons
J. Neurosci., February 16, 2005; 25(7): 1750 - 1760.
[Abstract] [Full Text] [PDF]
B. D. Burrell and C. L. Sahley
Multiple Forms of Long-Term Potentiation and Long-Term Depression Converge on a Single Interneuron in the Leech CNS
J. Neurosci., April 21, 2004; 24(16): 4011 - 4019.
[Abstract] [Full Text] [PDF]
A. Sakurai and P. S. Katz
Spike Timing-Dependent Serotonergic Neuromodulation of Synaptic Strength Intrinsic to a Central Pattern Generator Circuit
J. Neurosci., November 26, 2003; 23(34): 10745 - 10755.
[Abstract] [Full Text] [PDF]
G. Daoudal and D. Debanne
Long-Term Plasticity of Intrinsic Excitability: Learning Rules and Mechanisms
Learn. Mem., November 1, 2003; 10(6): 456 - 465.
[Abstract] [Full Text] [PDF]
G. Daoudal, Y. Hanada, and D. Debanne
Bidirectional plasticity of excitatory postsynaptic potential (EPSP)-spike coupling in CA1 hippocampal pyramidal neurons
PNAS, October 29, 2002; 99(22): 14512 - 14517.
[Abstract] [Full Text] [PDF]
B. D. Burrell, C. L. Sahley, and K. J. Muller
Differential Effects of Serotonin Enhance Activity of an Electrically Coupled Neural Network
J Neurophysiol, June 1, 2002; 87(6): 2889 - 2895.
[Abstract] [Full Text] [PDF]
T. Crow and L.-M. Tian
Morphological Characteristics and Central Projections of Two Types of Interneurons in the Visual Pathway of Hermissenda
J Neurophysiol, January 1, 2002; 87(1): 322 - 332.
[Abstract] [Full Text] [PDF]
S. A. Baccus, C. L. Sahley, and K. J. Muller
Multiple Sites of Action Potential Initiation Increase Neuronal Firing Rate
J Neurophysiol, September 1, 2001; 86(3): 1226 - 1236.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|