PT  - JOURNAL ARTICLE
AU  - Lena K. L. Oestreich
AU  - Thomas J. Whitford
AU  - Marta I. Garrido
TI  - The functional anatomy of self-generated and predictable speech
AID  - 10.1101/119644
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 119644
4099  - http://biorxiv.org/content/early/2017/03/22/119644.short
4100  - http://biorxiv.org/content/early/2017/03/22/119644.full
AB  - Sensory attenuation refers to the cortical suppression of self-generated sensations relative to externally-generated sensations. This attenuation of cortical responsiveness is the result of internal forward models which make precise predictions about forthcoming sensations. Forward models of sensory attenuation in the auditory domain are thought to operate along auditory white matter pathways such as the arcuate fasciculus and the frontal aslant. The aim of this study was to investigate whether brain regions that are structurally connected via these white matter pathways are also effectively connected during overt speech, as well as as when listening to externally-generated speech that is temporally predictable via a visual cue. Using Electroencephalography (EEG) and Dynamic Causal Modelling (DCM) we investigated network models that link the primary auditory cortex to Wernicke’s and Broca’s area either directly or indirectly through Geschwind’s territory, which are structurally connected via the arcuate fasciculus. Connections between Broca’s and supplementary motor area, which are structurally connected via the frontal aslant, were also included. Our results revealed that bilateral areas interconnected by indirect and direct pathways of the arcuate fasciculus, in addition to regions interconnected by the frontal aslant best explain the EEG responses to both self-generated speech, and speech that is externally-generated but temporally predictable. These findings indicate that structurally connected brain regions thought to be involved in auditory attenuation are also effectively connected. Critically, our findings expand on the notion of internal forward models, whereby sensory consequences of our actions are internally predicted and reflected in reduced cortical responsiveness to these sensations.Significance statement Auditory attenuation refers to the reduction of cortical responsiveness to sensations resulting from self-generated actions relative to identical sensations that are externally generated. This attenuation is thought to be caused by internal forward models whereby self-generated sensations such as speech and thought are predicted via an efference copy of the motor command. These efference copies have been suggested to be sent along auditory white matter pathways which connect brain regions involved in speech production and processing. The findings from the present study indicate that structurally connected brain areas involved in auditory attenuation are also effectively connected, which is in line with the notion of internal forward models of auditory attenuation to self-generated and predictable speech.