Book contents
- Frontmatter
- Contents
- Preface
- 1 Anatomy of the cerebral cortex
- 2 The probability for synaptic contact between neurons in the cortex
- 3 Processing of spikes by neural networks
- 4 Relations between membrane potential and the synaptic response curve
- 5 Models of neural networks
- 6 Transmission through chains of neurons
- 7 Synchronous transmission
- Appendix Answers and hints
- Index
4 - Relations between membrane potential and the synaptic response curve
Published online by Cambridge University Press: 03 May 2011
- Frontmatter
- Contents
- Preface
- 1 Anatomy of the cerebral cortex
- 2 The probability for synaptic contact between neurons in the cortex
- 3 Processing of spikes by neural networks
- 4 Relations between membrane potential and the synaptic response curve
- 5 Models of neural networks
- 6 Transmission through chains of neurons
- 7 Synchronous transmission
- Appendix Answers and hints
- Index
Summary
In Chapter 3 we discussed the input-output relations of synaptic connections, as measured by spike-train analysis. In this chapter we attempt to relate these phenomenological transmission curves to intracellular synaptic mechanisms. There appears to be no uniquely accurate way of translating the membrane potential changes into firing rates, though two extreme cases can be understood fairly well. The first case is that of a neuron whose membrane potential hyperpolarizes strongly after each action potential, and then begins to depolarize gradually until it hits the threshold and fires again. Firing times of such neurons are quasi-periodic. The second case is that of a neuron whose membrane potential fluctuates strongly around a constant mean level and whose excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) are small.
Both types of neurons can be found in the mammalian nervous system. We refer to them as the periodically firing neurons and the randomly firing neurons. Sections 4.1 and 4.2 deal with the analysis of firing times in these two types of neurons. Section 4.3 describes the autocorrelation function and shows how it can be used to distinguish between the two types of neurons. It also shows that cortical neurons behave like randomly firing neurons. Sections 4.4 and 4.5 describe the expected modulations of firing rates generated by a postsynaptic potential in these two types of neurons.
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- Chapter
- Information
- CorticonicsNeural Circuits of the Cerebral Cortex, pp. 118 - 149Publisher: Cambridge University PressPrint publication year: 1991
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