Methodological considerations when measuring and analyzing auditory steady-state responses with multi-channel EEG

Dysfunction of specific auditory fibers impacts cortical oscillations, driving an autism phenotype despite near‐normal hearing

“…To further determine whether the source of the reduced sound‐evoked LFP responses in Bdnf Pax2 KO mice stems from cortical or subcortical nuclei, we analyzed the signal envelope following responses to amplitude‐modulated stimuli (ASSRs). ASSRs reflect the summation of phase‐locked activity from multiple generators of neural stimuli within the auditory system, including the cochlea, auditory nerve, IC, and AC 43 . The contributions of ASSR sources in response to lower (10–40 Hz) modulation rates are dominated by cortical components, 43 while ASSRs in response to higher (>100 Hz) modulation rates are dominated by subcortical components 43 …”

“…ASSR amplitudes were depicted for 100% modulation depth at 90 dB SPL and plotted against the frequency oscillation bands (Figure 2; Figure S2). Evoked ASSR activity reflects bottom‐up sensory transmission primarily by driving inputs 43 . This evoked ASSR activity was distinguished from induced ASSR activities, which are not strictly locked to stimulus onset and rather represent internal dynamics of cortical networks related to higher cognitive functions 30,43 .…”

“…Evoked ASSR activity reflects bottom‐up sensory transmission primarily by driving inputs 43 . This evoked ASSR activity was distinguished from induced ASSR activities, which are not strictly locked to stimulus onset and rather represent internal dynamics of cortical networks related to higher cognitive functions 30,43 . As shown for the AC (Figure 2A), PFC (Figure 2D), HC (Figure S2A), and V1 (Figure S2D), evoked and induced ASSR amplitudes were significantly reduced in Bdnf Pax2 KO mice in response to 10‐, 40‐, and 128 Hz‐modulated tones and remained significantly diminished in comparison with control mice up to 320 Hz modulation frequency (see dashed lines in Figure 2A,D; Figure S2A,D).…”

“…Importantly, ASSRs reveal the synchronous discharge of auditory neurons phase‐locked to the modulation frequency of the stimulus 71–73 and thereby critically depend on proper phase‐locking capacity along the auditory pathway. The power (magnitude) and phase‐locking ability (phase consistency across trials) measured with ASSRs is dependent upon the summation of phase‐locked activity from multiple neural generators within the auditory system, including the cochlea, auditory nerve, IC, and AC 43 . It is likely that the phase‐locked activity of all these neural generators depends on the proper maturation of high‐SR ANFs, as this ANF type mainly contributes to the synchronized spike responses within the dynamic range of the auditory nerve response, while low‐SR ANFs have limited influence on synchronization 50 .…”

“…ASSRs reflect the summation of phaselocked activity from multiple generators of neural stimuli within the auditory system, including the cochlea, auditory nerve, IC, and AC. 43 The contributions of ASSR sources in response to lower (10-40 Hz) modulation rates are dominated by cortical components, 43 while ASSRs in response to higher (>100 Hz) modulation rates are dominated by subcortical components. 43 Modulation frequencies between 5 and 2048 Hz were used at an 11.3 kHz carrier frequency.…”