Journal: Frontiers in Neuroscience

Article Title: A Custom Microcontrolled and Wireless-Operated Chamber for Auditory Fear Conditioning

doi: 10.3389/fnins.2019.01193

Figure Lengend Snippet: Oscillations in the IC can be entrained by the envelope of an amplitude modulated tone. ( A , top) Representative time course of LFP (gray) and CS trials (light red, 10 kHz pure tone with an amplitude modulation of 53.7 Hz). ( A , Bottom) Highlight to a sample time window at the beginning of the fourth trial showing that the IC LFP synchronizes with the CS amplitude envelope. The LFP and the CS envelope were band-pass filtered between 40 and 70 Hz. (B) Spectrogram showing SSEP power at 53.7 Hz (a.u., Arbitrary units). ( C , left) Mean SSEP power at 53.7 Hz ± 3 Hz over trials for all animals. The figure shows a period of 30 s before CS onset, 30 s of CS presentation and 10 s after. ( C , right) Qualitative analysis of SSEP power at 53.7 Hz ± 3 Hz for 30 s before CS onset compared to the 30 s of CS presentation ( n = 5 animals; before CS vs. CS period; t ( 4 ) = 11.42, p = 0.0003). (D) Representative time course of delta phase values at 53.7 Hz ± 3 Hz (φ S S E P -φ C S ) extracted from the Hilbert coefficients (gray) and CS trials (light red). (E) Delta phase vectors computed for 250 ms time windows during CS presentation (gray lines) and the respective estimate mean phase values (red lines). The numbers above the polar plots represents the phase coherence of each trial during CS presentation. (F) Representative time course of instantaneous oscillatory frequency estimated at 53.7 Hz ± 3 Hz from the changes in the SSEP phase angles (gray) and CS trials (light red). (G) Distribution of instantaneous oscillatory frequencies over trials for 30 s before CS onset (light gray) and 30 s of CS presentation (light red) and their respective cumulative distributions. Two Sample Kolmogorov–Smirnov test was used to test whether the two samples come from the same distribution ( n = 5 animals; before CS vs. CS period delta phase angles distributions; KS = 0.3343, p < 0.0001).

Article Snippet: To calculate the Δ phase between CS amplitude modulating envelope and SSEP, the data were initially filtered at the frequency range of 53.7 ± 3 Hz and the coefficients were extracted by the built-in MATLAB function Hilbert transform.

Techniques:

Journal: PLoS ONE

Article Title: What can we learn about beat perception by comparing brain signals and stimulus envelopes?

doi: 10.1371/journal.pone.0172454

Figure Lengend Snippet: Since the MIR toolbox makes use of time-domain filtering, envelopes are smooth and frequency spectra differ from those obtained from the Matlab Hilbert transform. The most obvious discrepancy is at 2.5 Hz, where there is no energy in the spectrum obtained using the Matlab Hilbert function.

Article Snippet: For example, the built-in filtering applied by the MIR Toolbox [ ] naturally led to different frequency-domain representations than the Matlab hilbert function applied without filtering.

Techniques: