Probing and Sampling#
Both cable cells and LIF cells can be probed, see here for more details on cells Cells. The LIF cell, however, has a much smaller set of observable quantities and only offers scalar probes. Thus, the following discussion is tailored to the cable cell.
Definitions#
- probe#
A measurement that can be performed on a cell. Each cell kind will have its own sorts of probe. Cable cells (
arbor.cable_probe) allow the monitoring of membrane voltage, total membrane current, mechanism state, and a number of other quantities, measured either over the whole cell, or at specific sites (see Cable cell probing and sampling).- vector probe#
Certain probes work over a region rather than a locset. This means that, depending settings such as cv policy, data is sampled as a function of distance, yielding multiple data points. Such probes are distinguished from regular probes as “vector probes”.
- probeset#
A set of probes. Probes are placed on locsets, and therefore may describe more than one probe.
- probeset address#
Probesets are located at a probeset address, and the collection of probeset addresses for a given cell is provided by the
recipeobject. One address may correspond to more than one probe: as an example, a request for membrane voltage on a cable cell at sites specified by a locset expression will generate one probe for each site in that locset expression.See Cable cell probing and sampling for a list of objects that return a probeset address.
- probeset id#
A designator for a probeset as specified by a recipe. The probeset id is a
cell_memberreferring to a specific cell by gid, and the index into the list of probeset addresses returned by the recipe for that gid.- metadata#
Each probe has associated metadata describing, for example, the location on a cell where the measurement is being taken, or other such identifying information. Metadata for the probes associated with a probeset id can be retrieved from the simulation object, and is also provided along with any recorded samples.
- sampler#
- sample_recorder#
A sampler is something that receives probeset data. It amounts to setting a particular probeset to a particular measuring schedule, and then having a handle with which to access the recorded probeset data later on.
- sample#
A record of data corresponding to the value at a specific probe at a specific time.
- handle#
A handle for reaching sampling data associated to a sampler, which is associated to a probeset. Setting a sampler (through
simulation.sample()) returns handles. Sampled data can be retrieved by passing the handle associated to a sampler (associated to a probeset) tosimulation.samples().- schedule#
An object representing a series of monotonically increasing points in time, used for determining sample times (see Recipes).
Spiking#
Threshold detectors have a dual use: they can be used to record spike times, but are also used in propagating signals between cells. See also threshold detector and 2. Threshold detectors..