code: def subcortical_waveform(times):
      """Create a subcortical waveform."""
      return 10e-9 * np.cos(times * 2 * np.pi * 239)
  
imports: import matplotlib.pyplot
  import numpy
  import mne
  from mne.datasets import sample
  from mne.simulation import simulate_evoked, simulate_sparse_stc
label_desc: Use image node_id 2 for calling a global function with example usage: subcortical_waveform(times) and returns: unknown