---

name: recording description: "Record Brian2 2.9.0 spikes, state variables, custom events, rates, subsets, and monitor data with explicit timing, memory, and export choices." disable-model-invocation: true metadata: disco-role: operating license: NOASSERTION

Brian2 recording

Use this route after the model and its inputs/events exist. It owns monitor selection, recording semantics, timing of observations, monitor data access, subsets, rates, and export. It does not own model equations or the run lifecycle.

Route quickly

• Read API reference for constructor arguments, shapes, units, indexing, event/spike summaries, EventClock, endpoint sampling, and rate methods.
• Read workflows for the attach/run/validate pattern, late monitors, timing diagnosis, subgroup recording, and export.
• Read data and memory before using record=True, recording many variables, or keeping a long trace.
• Read troubleshooting for import and optional dependency failures, missing variables/events, timing shifts, standalone limits, and data/configuration mistakes.
• Run the plotting-free tiny contract with python scripts/monitor_smoke.py --help, then python scripts/monitor_smoke.py in an installed Brian2 2.9.0 environment.

Choose the monitor

• SpikeMonitor(source, variables=None, record=True, when=None, order=None) records spike indices/times and per-source-neuron counts. Set record=False when only counts are needed.
• EventMonitor(source, event, variables=None, record=True, when=None, order=None) records a named event declared by the source. It is the route for custom events; SpikeMonitor is the spike-event specialization.
• StateMonitor(source, variables, record, dt=None, clock=None, when="start") records selected state variables as time-by-index arrays. record=True means every source index and may consume substantial memory.
• PopulationRateMonitor(source) records the instantaneous population rate at the source clock resolution. Use binned_rate or smooth_rate after the run for derived rates.

Safe operating sequence

1. Create the monitor before the run and keep a strong reference. Prefer an explicit Network when monitors are created, activated, or removed between runs; a monitor cannot recover events or state values from before it was attached.
2. Choose the smallest set of variables, indices, source subgroup, and time resolution needed. For StateMonitor, record=[...] and a slower dt are usually safer than record=True at the source clock.
3. Decide when, order, and dt deliberately when a value can change from integration, thresholding, reset, event handlers, or same-step code. The default StateMonitor slot is start; spike/event monitors follow the emitted event; PopulationRateMonitor records at end. For a final post-run state, initialize the monitor with a run and then use record_single_timestep() rather than shifting the time array.
4. Run through the simulation lifecycle route, then check time origin, counts, array shape, units, and subgroup index meaning before analysis. For a late monitor, distinguish the population-rate bin origin from the spike/event binning behavior described in the API reference.
5. Export selected monitor state with get_states(...) (copies) rather than internal storage. Preserve units and the recording metadata; use units=False only when the consumer explicitly requires unitless arrays.
6. For a long run, checkpoint or export a bounded segment, stop/deactivate or remove the monitor, release its arrays, and attach a new monitor for the next segment. Do not silently retain all segments in memory.

Boundaries

• Network construction, run, clocks, schedules, active, store/restore, devices, and execution lifecycle route to simulation-and-recording.
• NeuronGroup/Synapses equations, thresholds, resets, custom event definition, inputs, and subgroup/model construction route to modeling/synapses-and-inputs.
• Plotting packages, GUI backends, and figure rendering route to the root troubleshooting route. This skill and its smoke script intentionally do not plot.

Acceptance gates

A recording is usable only when the monitor was attached to the intended source, the first and last times are understood, the array shape matches the selected indices, and units or the unitless conversion are explicit. Treat record=False, an empty record selection, incomplete final bins, a monitor attached mid-run, and standalone result deletion as intentional choices that must be documented in the handoff or experiment output.