Representation of Sound Objects within Early-Stage Auditory Areas: A Repetition Effect Study Using 7T fMRI

Abstract

Environmental sounds are highly complex stimuli whose recognition depends on the interaction of top-down and bottom-up processes in the brain. Their semantic representations were shown to yield repetition suppression effects, i. e. a decrease in activity during exposure to a sound that is perceived as belonging to the same source as a preceding sound. Making use of the high spatial resolution of 7T fMRI we have investigated the representations of sound objects within early-stage auditory areas on the supratemporal plane. The primary auditory cortex was identified by means of tonotopic mapping and the non-primary areas by comparison with previous histological studies. Repeated presentations of different exemplars of the same sound source, as compared to the presentation of different sound sources, yielded significant repetition suppression effects within a subset of early-stage areas. This effect was found within the right hemisphere in primary areas A1 and R as well as two non-primary areas on the antero-medial part of the planum temporale, and within the left hemisphere in A1 and a non-primary area on the medial part of Heschl’s gyrus. Thus, several, but not all early-stage auditory areas encode the meaning of environmental sounds.

Emotional sounds in space: asymmetrical representation within early-stage auditory areas

“…Then, briefly, based on the resulting individual frequency reversals and anatomical landmarks, each early-stage auditory area was localized and defined in each subject as the primary auditory cortex, A1 and R, as well as the lateral (L1, L2, L3, L4) and medial non-primary areas (M1, M2, M3, M4). The coordinates of these regions were in accordance with previously published values (Table 1; Viceic et al, 2006;van der Zwaag et al, 2011;Da Costa et al, 2015.…”

“…The subdivision of the early-stage auditory areas was carried out in individual subjects as described previously (Da Costa et al, 2015. The subjects listened to two runs (one ascending and one descending) of a tonotopic mapping paradigm, which consisted of progressions of 2 s-bursts of pure tones (14 frequencies, between 88 and 8,000 Hz, in half octave steps) presented in 12 identical cycles of 28 s followed by a 12-s silent pause for a total duration of 8 min (as in previous studies Da Costa et al, 2011Costa et al, , 2013Costa et al, , 2015Costa et al, , 2018.…”

“…The subdivision of the early-stage auditory areas was carried out in individual subjects as described previously (Da Costa et al, 2015. The subjects listened to two runs (one ascending and one descending) of a tonotopic mapping paradigm, which consisted of progressions of 2 s-bursts of pure tones (14 frequencies, between 88 and 8,000 Hz, in half octave steps) presented in 12 identical cycles of 28 s followed by a 12-s silent pause for a total duration of 8 min (as in previous studies Da Costa et al, 2011Costa et al, , 2013Costa et al, , 2015Costa et al, , 2018. Then, briefly, based on the resulting individual frequency reversals and anatomical landmarks, each early-stage auditory area was localized and defined in each subject as the primary auditory cortex, A1 and R, as well as the lateral (L1, L2, L3, L4) and medial non-primary areas (M1, M2, M3, M4).…”

Using high spatial resolution fMRI to understand representation in the auditory network

“…Building on low-level acoustics as input, an abstract sound representation is created via auditory cortical processing ( Da Costa et al, 2015 ; Giordano et al, 2013 ). Despite numerous investigations, how categorical responses emerge from the different acoustic features that serve as input to the early auditory cortex remains unclear.…”

Roaring lions and chirruping lemurs: How the brain encodes sound objects in space

“…The anterior lateral area (ALA), a belt area on the antero-lateral part of Heschl's gyrus (Wallace et al 2002), can process information related to sound identity (Viceic et al 2006) as well as combination of binaural information with spectro-temporal (Budd et al 2003;Hall et al 2005) or sound identity cues (van der Zwaag et al 1011). The planum temporale, which comprises posterior belt areas, contains neuronal populations that process the identity of sound objects (Da Costa et al 2015); spatial (Deouell et al 2007) or binaural cues (Krumbholz et al 2005); or combined information about frequency and sound location (Shrem and Deouell 2014). In 4 In view of the growing body of studies involving the supratemporal plane, there is a need to establish a common way of identifying early stage auditory areas.…”