Abstract
Synaptic connections from a neuron onto itself (autapses) are not uncommon [1], but their contributions to information processing and behavior are not fully understood. Positive feedback mediated by autapses could in principle give rise to persistent activity, a property of some neurons in which a brief stimulus causes a long-lasting response [2]. We have identified an autapse that underlies a plateau potential causing persistent activity in the B31/B32 neurons of Aplysia. The persistent activity is essential to the ability of these neurons to initiate and maintain components of feeding behavior. Persistent activity in B31/B32 arises from a voltage-dependent muscarinic autapse and from pharmacologically identical network-based positive feedback. Depolarization via the autapse begins later than network-driven excitation, and the effect of the autapse is therefore overshadowed by the earlier network-based depolarization. In B31/B32 neurons isolated in culture only the autapse is present, and the autapse functionally replaces the missing network-based feedback. Properties of B31/B32 provide insight into a possible general function of autapses. Autapses might function along with synapses from presynaptic neurons as components of feedback loops.
Original language | English |
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Pages (from-to) | 479-484 |
Number of pages | 6 |
Journal | Current Biology |
Volume | 19 |
Issue number | 6 |
DOIs | |
State | Published - 24 Mar 2009 |
Bibliographical note
Funding Information:We thank Samuel Schacher for advice and help in establishing the tissue culture techniques, Leonard J. Cleary and Alexander Perelman for advice on morphology, and John Koester and Alon Korngreen for comments on the manuscript. The research was supported by grant 420/06 from the Israel Science Foundation. All authors contributed to planning and interpreting the experiments. R.S. and I.H. performed in situ intracellular recordings. R.S. performed the microscopy. N.M. and R.S. prepared the cell cultures and recorded from cultured neurons. A.J.S. wrote the manuscript.
Funding
We thank Samuel Schacher for advice and help in establishing the tissue culture techniques, Leonard J. Cleary and Alexander Perelman for advice on morphology, and John Koester and Alon Korngreen for comments on the manuscript. The research was supported by grant 420/06 from the Israel Science Foundation. All authors contributed to planning and interpreting the experiments. R.S. and I.H. performed in situ intracellular recordings. R.S. performed the microscopy. N.M. and R.S. prepared the cell cultures and recorded from cultured neurons. A.J.S. wrote the manuscript.
Funders | Funder number |
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Israel Science Foundation |
Keywords
- SYSNEURO