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Review – Objectives Transitioning 4-5 • Spikes can be detected from many neurons near the electrode tip. What are some ways to determine which spikes belong to which neurons? • Describe how a tetrode helps isolate spikes • What kind of probes are better for current source density of LFPs and what kind are better for single unit isolation (of spiking activity)? Review – Objectives Transitioning 4-5 • What does a Fourier analysis do to a time-varying signal, like LFPs or ECoG? (Why would a neuroscientist use it?) • Describe an assumption that is made about the signal you process with Fourier analysis. (p.105 and footnote) • Name the two parameters that are orthogonal (i.e. independent) in a Fourier analysis. (Related to previous question) • Describe a solution that allows both of the independent parameters to be characterized (p. 106) Review – Objectives Cycle 5 • Give the term for the magnitude of a given frequency band – one output of a Fourier transform. • An increase in magnitude of the Fourier transform can arise from two separate changes in the signal. Name them. (this relates to the independence question) • Brain oscillations occur at specific frequency bands during specific behavioural states. Collectively, what relationship do the observed bands have? Shown in figure 5.1 • List several reasons the brain might have so many oscillations (p. 114) Review – Objectives Cycle 5 • An EEG signal shows a power-law relationship between what two parameters? • Define (or draw) white pink and brown noise and describe ways in which they differ. • Select the type of noise associated with cortical activity, and give and example of when that activity deviates from ‘pink’. Cycle 6: Oscillations and Synchrony • What is an oscillator? – Name two types of oscillators – Components of oscillations • Define differences between types of oscillators: • Oscillators can be considered at the neuron or neural population level. Give a description at each level. Cycle 6: Oscillations and Synchrony How could resonance at varying frequencies be accomplished? p. 144 What is the low-information problem and what is a neuron’s default state, giving examples. Define Synchrony, including the concept of a ‘time constant’. How does synchrony differ across classes of oscillators? Cycle 6: Oscillations and Synchrony • Define stochastic resonance, providing two ‘scenarios’ of how it could operate in the brain. • Describe features of cell assemblies, and why their action may be useful in encoding patterns. • Describe how synchrony is efficient Cycle 7: thalamocortical circuit • Describe the ion channel dynamics responsible for thalamocortical oscillations. Know the specific role of It, Ih, Na, and Ca++ currents in producing the delta rhythms in thalamocortical cells.