**Name:**

correlospinmatrix_detector - Device for measuring the covariance matrix

from several inputs

**Description:**

The correlospinmatrix_detector is a recording device. It is used

to record correlations from binary neurons from several binary sources and

calculates the raw auto and cross correlation binned to bins of duration

delta_tau. The result can be obtained via GetStatus under the key

/count_covariance. The result is a tensor of rank 3 of size

N_channels x N_channels, with each entry C_ij being a vector of size

2*tau_max/delta_tau + 1 containing the histogram for the different time lags.

The bins are centered around the time difference they represent, and are

left-closed and right-open in the lower triangular part of the matrix. On the

diagonal and in the upper triangular part the intervals are left-open and

right-closed. This ensures proper counting of events at the border of bins.

The correlospinmatrix_detector has a variable number of inputs which can be

set via SetStatus under the key N_channels. All incoming connections to a

specified receptor will be pooled.

**Parameters:**

Tstart double - Time when to start counting events. This time should

be set to at least start + tau_max in order to avoid

edge effects of the correlation counts.

Tstop double - Time when to stop counting events. This time should be

set to at most Tsim - tau_max, where Tsim is the

duration of simulation, in order to avoid edge effects

of the correlation counts.

delta_tau double - bin width in ms. This has to be a multiple of the

resolution.

tau_max double - one-sided width in ms. In the lower triangular part

events with differences in [0, tau_max+delta_tau/2)

are counted. On the diagonal and in the upper

triangular part events with differences in (0,

tau_max+delta_tau/2]

N_channels long - The number of inputs to correlate. This defines the

range of receptor_type. Default is 1.

count_covariance matrix of long vectors, read-only - raw, auto/cross

correlation counts

**Receives:**

SpikeEvent

**Remarks:**

This recorder does not record to file, screen or memory in the usual

sense. The result must be obtained by a call to GetStatus. Setting either

N_channels, Tstart, Tstop, tau_max or delta_tau clears count_covariance.

Example:

See also pynest/examples/correlospinmatrix_detector_two_neuron.py

for a script reproducing a setting studied in Fig 1 of Grinzburg &

Sompolinsky (1994) PRE 50(4) p. 3171.

See also examples/nest/correlospinmatrix_detector.sli for a basic

example in sli.

/sg1 /spike_generator Create def

/sg2 /spike_generator Create def

/sg3 /spike_generator Create def

/csd /correlospinmatrix_detector Create def

csd << /N_channels 3 /tau_max 10. /delta_tau 1.0 >> SetStatus

sg1 << /spike_times [10. 10. 16.] >> SetStatus

sg2 << /spike_times [15. 15. 20.] >> SetStatus

% one final event needed so that last down transition will be detected

sg3 << /spike_times [25.] >> SetStatus

sg1 csd << /receptor_type 0 >> Connect

sg2 csd << /receptor_type 1 >> Connect

sg3 csd << /receptor_type 2 >> Connect

100. Simulate

**Availability:**

NEST

**Author:**

Moritz Helias

**FirstVersion:**

2015/08/25

**SeeAlso:**

**Source:**

/home/graber/work-nest/nest-git/nest-simulator/models/correlospinmatrix_detector.h