Human frequency-following responses to monaural and binaural stimuli

Binaural Interaction in the Human Frequency-Following Response: Effects of Interaural Intensity Difference

“…The compressive amplitude growth function for the binaural FFR compared to the monaural summed FFR observed in this study is consistent with the above explanation. Although all of these results make a compelling case in support of binaural interaction among neural elements in the brainstem it should be noted that Gerken et al [28] interpreted the absence of an interaction component in their 500-Hz FFR, based solely on visual inspection of response waveforms, to mean that the binaural FFR is generated by two independent monaural neural populations. However, these authors concede that they could have demonstrated the presence of a BIC had they derived the difference potential between the binaural and the summed monaural response.…”

Multichannel recordings of the human brainstem frequency-following response: Scalp topography, source generators, and distinctions from the transient ABR

“…As stated by Gerken et al (1975), "It is also argued that the frequency-following response is not a microphonic-like response but rather that the individual waves in the [FFR] are evoked by the collective activity of phase-locked single units." This assumption implies that the FFR (sustained response) and ABR (onset response) are functional derivatives of one another and furthermore, that they are generated by the same population of neural elements.…”

“…computed as the location of peak voltage within the 8e12 ms search windowdthe putative latency range of the brainstem FFR (Galbraith et al, 2000). Differences in the time-course and spectrotemporal properties of derived vs. actual recordings were used to assess the validity of the convolution model of FFR generation (e.g., Dau, 2003;Gerken et al, 1975;Janssen et al, 1991). Under the linear superposition assumption that the FFR is a repeated and overlapping ABR, we expected to observe no differences in spectrotemporal features between derived and actual recordings.…”

“…There has been a long theoretical debate regarding the functional distinctions between the sustained (FFR) and transient (ABR) brainstem evoked potentials (e.g., Daly et al, 1976;Dau, 2003;Davis and Hirsh, 1974;Gerken et al, 1975;Janssen et al, 1991;Picton et al, 1977). Modeling work has suggested that the periodic FFR may reflect a series of repeated and overlapping onset ABR responses (Dau, 2003;Janssen et al, 1991).…”

“…However, to our knowledge, this "convolution model" of the FFR generation has never been fully authenticated in humans. The present study directly tested the hypothesis that the sustained human brainstem FFR is simply a series of overlapping onset ABRs (e.g., Daly et al, 1976;Dau, 2003;Davis and Hirsh, 1974;Gerken et al, 1975;Janssen et al, 1991;Picton et al, 1977).…”