The research program is focused on the neural and molecular mechanisms underlying information storage. Previously Dr. Byrne found that a classical conditioning protocol applied directly to individual tail sensory neurons results in an associative modification of the monosynaptic connections to motor neurons. Sensory neurons receiving a conditioned stimulus (CS, intracellular activation of the sensory neuron) immediately before the unconditioned stimulus (US, tail shock) show significantly more synaptic facilitation than sensory neurons exposed to the US alone or to unpaired CS and US applications. An analog of the classical conditioning paradigm produces a selective amplification of the cAMP content of isolated sensory neuron clusters. These results indicate that a pairing- specific enhancement of cAMP levels may be a biochemical mechanism for associative learning. Experiments proposed here are designed to extend these analyses. Specifically, Dr. Byrne will examine 1) whether Ca2+ serves as the signal for the induction of the associative change, 2) whether cAMP levels in the sensory neurons are increased during simple forms of learning such as sensitization and classical conditioning, 3) the contribution of spike broadening in the sensory neurons to synaptic facilitation and behavioral modification, 4) the properties of the neural circuit elements mediating the reflex and effects of the US, and 5) the coordination and modulation of synergistic defensive responses triggered by tail stimulation. Continued analysis of this system promises to yield much additional information concerning the cellular mechanisms underlying associative and nonassociative learning. The award will foster Dr. Byrne's research development and professional growth. It will allow him to expand his research program by hiring a junior colleague. It will give Dr. Byrne the flexibility to plan interludes to develop new areas of expertise through collaboration and visits with other scientists in the field.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02MH000649-05
Application #
3070039
Study Section
Research Scientist Development Review Committee (MHK)
Project Start
1986-09-30
Project End
1991-08-31
Budget Start
1990-09-01
Budget End
1991-08-31
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Type
Schools of Medicine
DUNS #
City
Houston
State
TX
Country
United States
Zip Code
77225
Byrne, J H; Zwartjes, R; Homayouni, R et al. (1993) Roles of second messenger pathways in neuronal plasticity and in learning and memory. Insights gained from Aplysia. Adv Second Messenger Phosphoprotein Res 27:47-108
Goldsmith, J R; Byrne, J H (1993) Bag cell extract inhibits tail-siphon withdrawal reflex, suppresses long-term but not short-term sensitization, and attenuates sensory-to-motor neuron synapses in Aplysia. J Neurosci 13:1688-700
Buonomano, D V; Cleary, L J; Byrne, J H (1992) Inhibitory neuron produces heterosynaptic inhibition of the sensory-to-motor neuron synapse in Aplysia. Brain Res 577:147-50
Endo, S; Shenolikar, S; Eskin, A et al. (1992) Characterization of neuronal protein phosphatases in Aplysia californica. J Neurochem 58:975-82
Pieroni, J P; Byrne, J H (1992) Differential effects of serotonin, FMRFamide, and small cardioactive peptide on multiple, distributed processes modulating sensorimotor synaptic transmission in Aplysia. J Neurosci 12:2633-47
Critz, S D; Byrne, J H (1992) Modulation of IK,Ca by phorbol ester-mediated activation of PKC in pleural sensory neurons of Aplysia. J Neurophysiol 68:1079-86
Zhang, Z S; Fang, B; Marshak, D W et al. (1991) Serotoninergic varicosities make synaptic contacts with pleural sensory neurons of Aplysia. J Comp Neurol 311:259-70
Canavier, C C; Clark, J W; Byrne, J H (1991) Simulation of the bursting activity of neuron R15 in Aplysia: role of ionic currents, calcium balance, and modulatory transmitters. J Neurophysiol 66:2107-24
Nazif, F A; Byrne, J H; Cleary, L J (1991) cAMP induces long-term morphological changes in sensory neurons of Aplysia. Brain Res 539:324-7
Ichinose, M; Byrne, J H (1991) Role of protein phosphatases in the modulation of neuronal membrane currents. Brain Res 549:146-50

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