Glossary¶
A glossary of terms used in the module, with brief descriptions of what each term means and how it is used, as well as a list of common abbreviations.
Spiking Data¶
- action potential / spike¶
An action potential is an event in which a neuron rapidly depolarizes, initiating a cascade of events that can influence the activity of connected neurons. In general, we will refer to action potentials as ‘spikes’.
- unit / single unit¶
A general term used to refer to a putatively individual neuron that is, for example, the source for a set of recorded spikes.
- multi-unit¶
A general term used to refer to a situation in which there are thought to be multiple neurons contributing to a set of recorded spikes.
- spike times¶
A representation of spiking activity based on listing the times at which spikes occur.
- spike train¶
A representation of spiking activity in which each sample is either a 0 or 1, with 1 representing a spike.
- refractory period¶
The amount of time after an action potential happens during which the same neuron cannot initiate another action potential.
Spike Measures¶
- firing rate¶
How fast an individual unit is firing, typically measured in Hz, as spikes per second.
- coefficient of variation¶
A measure of the variability of unit firing, reflecting the dispersion of the data around the mean.
- fano factor¶
A measure of the variability of unit firing, as a variant of the coefficient of variation.
- interspike interval (ISI)¶
A measure of the time interval(s) between successive spikes.
- waveform / spike waveform¶
The shape of the action potential.
- raster / raster plot¶
A visualization of spike activity across time, representing each spike as a vertical line.
Recording¶
- electrode¶
A recording device that can measure electrical activity, that is used to collect the raw data.
- extracellular recording¶
A recording in which the electrode sits in the extracellular fluid, outside of any individual cells.
- intracellular recording¶
A recording in which an electrode is inserted into an individual cell.
- micro-electrode¶
An electrode that is very small, such that if it is close enough, it can record activity from single-units that are nearby.
- tetrode¶
A recording device with four small electrodes that can record single unit activity. The multiple wires help to differentiate different units.
- sampling rate¶
The rate at which samples are collected on a recording device.
- neurodata without borders¶
A standardized file type for storing neuro-electrophysiological data.
Pre-Processing¶
- spike sorting¶
The process of identifying spikes and grouping them into clusters that represent putative single-neuron activity.
Measurement Units¶
- Hertz (Hz)¶
A unit of frequency, used to measure the number of spikes per second.