voltmeter - Device to record membrane potential from neurons.
voltmeter Create  

SLI ] /iaf_cond_alpha Create /n Set
SLI ] /voltmeter Create /vm Set
SLI ] vm << /interval 0.5 >> SetStatus
SLI ] vm n Connect
SLI ] 10 Simulate
SLI ] vm /events get info
Name Type Value
senders intvectortype
times doublevectortype
V_m doublevectortype
Total number of entries: 3

A voltmeter records the membrane potential (V_m) of connected nodes
to memory, file or stdout.

By default, voltmeters record values once per ms. Set the parameter
/interval to change this. The recording interval cannot be smaller
than the resolution.

Results are returned in the /events entry of the status dictionary,
which contains membrane potential as vector /V_m and pertaining
times as vector /times and node GIDs as /senders, if /withtime and
/withgid are set, respectively.

Accumulator mode:
Voltmeter can operate in accumulator mode. In this case, values for all
recorded variables are added across all recorded nodes (but kept separate in
time). This can be useful to record average membrane potential in a

To activate accumulator mode, either set /to_accumulator to true, or set
/record_to [ /accumulator ]. In accumulator mode, you cannot record to file,
to memory, to screen, with GID or with weight. You must activate accumulator
mode before simulating. Accumulator data is never written to file. You must
extract it from the device using GetStatus.

The following parameter can be set in the status dictionary:
interval double - Recording interval in ms


- The voltmeter model is implemented as a multimeter preconfigured to
record /V_m.
- The set of variables to record and the recording interval must be set
BEFORE the voltmeter is connected to any node, and cannot be changed
- A voltmeter cannot be frozen.
- If you record with voltmeter in accumulator mode and some of the nodes
you record from are frozen and others are not, data will only be collected
from the unfrozen nodes. Most likely, this will lead to confusing results,
so you should not use voltmeter with frozen nodes.

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