Create Stimulus

This module provides functionality to create stimulus sequences for sensory perturbations. The stimulus sequences can be exportet in a format that is readable in Anaropia and Anaropia legacy Virtual Reality experimental setups.

balancepy.make_stimulus.make_prts(type='mseq', ncyc=1, ampl=1, vel=0, samplingrate_Hz=1000, t_state=0.25, base=3, power=4, seq=1, shift=0)

Generate a stimulus based on m-sequence or other types.

Parameters:

• type (str, optional) – Type of stimulus (‘Peterka2002’, ‘prts_20s’, ‘mseq’, etc.).

• ncyc (int, optional) – Number of cycles to repeat the stimulus.

• ampl (float, optional) – Amplitude of the stimulus.

• vel (float, optional) – Velocity scaling factor.

• samplingrate_Hz (int, optional) – Sampling rate in Hz.

• t_state (float, optional) – Time per state in seconds.

• base (int, optional) – Base for m-sequence generation.

• power (int, optional) – Power for m-sequence generation.

• seq (int, optional) – Sequence instantiation to use.

• shift (int, optional) – Cyclical shift of the sequence.

Returns:

stim – Generated stimulus.

Return type:

np.ndarray

balancepy.make_stimulus.make_sine(frequency_Hz=1, ncyc=1, ampl=1, samplingrate_Hz=1000, phase=0)

Generate a sine wave stimulus.

Parameters:

• frequency_Hz (float, optional) – Frequency of the sine wave in Hz.

• ncyc (int, optional) – Number of cycles to repeat the sine wave.

• ampl (float, optional) – Amplitude of the sine wave.

• samplingrate_Hz (int, optional) – Sampling rate in Hz.

• phase (float, optional) – Phase shift in radians.

Returns:

stim – Generated sine wave stimulus.

Return type:

np.ndarray

balancepy.make_stimulus.mseq(base_val, power_val, which_seq=1, shift=1)

Generate a maximum length sequence (m-sequence).

Parameters:

• base_val (int) – Number of sequence levels (2, 3, or 5 allowed).

• power_val (int) – Power, so that sequence length is base_val**power_val - 1.

• which_seq (int, optional) – Sequence instantiation to use (default is 1).

• shift (int, optional) – Cyclical shift of the sequence (default is 1).

Returns:

Generated maximum length sequence.

Return type:

np.ndarray

Notes

Adapted from the MATLAB code by Giedrius T. Buracas, SNL-B, Salk Institute.

References

Davies, W.D.T. (1970). System Identification for Self-Adaptive Control. Wiley-Interscience. Buracas, G.T. & Boynton, G.M. (2002). Efficient Design of Event-Related fMRI Experiments Using M-sequences. NeuroImage, 16, 801–813.

balancepy.make_stimulus.saveas_anaropia_legacy_stimulus(stim, stim_name='pitch', stimulus_index=1)

Save a stimulus in the legacy Anaropia format.

Note

Stimulus data must be sampled at 1000 Hz. Strict name conventions apply (see Parameters).

Parameters:

• stim (np.ndarray) – Stimulus data to save. Can be 1D or 2D.

• stim_name (str or list of str) –

  Name(s) of the stimulus. Options are:

  • ’pitch’: anterior-posterior rotation in degrees (default for 1D)

  • ’roll’: lateral-medial rotation in degrees

  • ’yaw’: vertical rotation in degrees

  • ’trans_ap’: anterior-posterior translation in meters

  • ’trans_ml’: lateral-medial translation in meters

  • ’trans_ud’: vertical translation in meters

  Can also be a list of strings for multi-dimensional stimuli.

• stimulus_index (int, optional) – Index for the filename. Output will be ‘vr_stim_[stimulus_index].csv’.