Low and high gamma auditory steady-states in response to 440 Hz carrier chirp-modulated tones show no signs of attentional modulation

Abstract

Auditory steady-state responses (ASSRs) are increasingly used as a neurodiagnostical tool and in neurotechnological applications where it is important to test responses at different frequencies.We aimed to evaluate EEG responses to a low-frequency carrier (440 Hz) tone modulated with 500 ms chirps at 1–120 Hz and to test the ability of stimulation to highlight the low and high gamma band activity. Increasing and decreasing modulation rates were applied. Subjective pleasantness of chirps and attentional effects on ASSRs to chirps were assessed.Our results suggest that brief low-frequency tones modulated with chirps can be used to evoke ASSRs and to test responses at low and high gamma frequencies. Moreover, chirps are perceived as moderately arousing and neutrally pleasant, while ASSRs to these sounds are not sensitive to attentional modulation. The abovementioned findings make chirp stimulation suitable for use in populations with increased perceptual sensitivity to auditory stimuli, for instance like patients with schizophrenia.