Predictive processing increases intelligibility of acoustically distorted speech: Behavioral and neural correlates
Research output: Contribution to journal › Article › Scientific › peer-review
|Number of pages||15|
|Journal||Brain and Behavior|
|Early online date||4 Aug 2017|
|Publication status||Published - Sep 2017|
|MoE publication type||A1 Journal article-refereed|
- University of Nottingham
- Leibniz Institute for Neurobiology
- University of Helsinki
Methods: In a functional magnetic resonance imaging (fMRI) experiment, a stimulus set contained a block of six distorted sentences. This was followed by the intact counterparts of the sentences, after which the sentences were presented in distorted form again. A total of 18 such sets were presented to 20 human subjects.
Results: The blood oxygenation level dependent (BOLD)-responses elicited by the distorted sentences which came after the disambiguating, intact sentences were contrasted with the responses to the sentences presented before disambiguation. This revealed increased activity in the bilateral frontal pole, the dorsal anterior cingulate/paracingulate cortex, and the right frontal operculum. Decreased BOLD responses were observed in the posterior insula, Heschl’s gyrus, and the posterior superior temporal sulcus.
Conclusions: The brain areas that showed BOLD-enhancement for increased sentence comprehension have been associated with executive functions and with the mapping of incoming sensory information to representations stored in episodic memory. Thus, the comprehension of acoustically distorted speech may be associated with the engagement of memory-related subsystems. Further, activity in the primary auditory cortex was modulated by prior experience, possibly in a predictive coding framework. Our results suggest that memory biases the perception of ambiguous sensory information toward interpretations that have the highest probability to be correct based on previous experience.
- Acoustic distortion, comprehension, fMRI, Intelligibility, memory, Speech