Neural plasticity associated with recently versus often heard objects

Abstract

In natural settings the same sound source is often heard repeatedly, with variations of the spectro-temporal and spatial characteristics. We have investigated how such repetitions influence sound representations and in particular how the auditory cortex keeps track of recently vs often heard objects. A set of 40 environmental sounds was presented twice, i.e. as prime and as repeat, within each of 16 experimental blocks, while subjects categorized the corresponding sound sources as living vs non-living. Electrical neuroimaging analyses were applied to auditory evoked potentials (AEPs) comparing primes vs repeats (effect of presentation) and the four sections (à 4 blocks each; effect of section). Dynamic analysis of distributed source estimations revealed i) one cluster within the left temporal convexity showing a significant main effect of presentation at 164-215ms post-stimulus onset; and ii) a cluster of significant main effect of section, in the right temporo-parietal junction at 166-213ms. Thus, spatio-temporal dynamics of neural activity encode the temporal history of exposure to sound objects. Rapidly occurring plastic changes within the semantic representations of the left hemisphere keep track of objects heard a few seconds before, independently of the more general sound exposure history. Progressively occurring and more long-lasting plastic changes within networks coding for perceptual, semantic and spatial aspects of sound objects within the right hemisphere keep track of multiple exposures.

Repetition-Induced Plasticity of Motor Representations of Action Sounds

“…In our study main effect of category was significant upon right hemispheric stimulation (p \ 0.05; no such effect was ; we would like to argue that the negative results for right hemispheric TMS in this study are due to a repetition effect, since only two hand-related sounds were used, typing and tearing paper, each presented 20 times. As demonstrated here, the right hand area is sensitive to repeats and may be even more so to numerous repetitions as is the predominantly right hemispheric auditory temporo-parietal network (Bourquin et al 2012). …”

“…Third, the auditory motor link could have an essentially perceptual role as part of the semantic representation of action-related sounds. Repetition suppression has been repeatedly shown to be a robust characteristic of semantic representations of environmental sounds, in particular on the left temporal convexity (Bergerbest et al 2004;Murray et al 2008;De Lucia et al 2010;Bourquin et al 2012). Its occurrence at the level of the auditorymotor link is a strong argument for considering the motor cortex as part of auditory semantic representations.…”

“…Repetition suppression, i.e. decrease of neural activity during repeated exposure, is characteristic of the core semantic representation of sound objects in the left temporal convexity (Bergerbest et al 2004;Murray et al 2008;De Lucia et al 2010;Bourquin et al 2012) and of category specific representation in the left and right supratemporal plane and superior temporal gyrus (Doehrmann et al 2008). If the auditory input to the primary motor cortex is part of the semantic representation of action-related sounds, it is likely to share its repetition priming features, including at the level of the motor output of the primary motor cortex.…”

Impact of Cognitive Neuroscience on Stroke Rehabilitation

“…43 The neuronal networks within the temporal lobe differentiate between sounds of living versus man-made categories as early as 70 ms post stimulus onset 44 and between the (nonverbal) vocalizations of humans versus animals at ≈170 ms. 38 Sounds related to actions yield different neural activity in the premotor cortex at ≈300 ms. 40 The neural networks within the temporal lobe keep track of prior exposure to the same sound object, even if other sounds have been heard in between; the so-called repetition priming effect occurs very early at 165 to 215 ms. 45 It is essentially semantic 38 and persists even after frequent exposure to the implicated sound objects. 46 The auditory representations within the 2 streams are highly plastic and can be modulated by even brief training.…”

“…прайминг-эффект повторения разви-вается через 165-215 мс [45]. Этот, в сущности, семан-тический эффект [38] сохраняется даже после частого контакта с сопричастными звуковыми объектами [46]. Слуховые представления в рамках двух потоков весь-ма пластичны и поддаются модулированию даже при кратковременной тренировке [47].…”