Saturday, December 7, 2013

Adaptive control during speech recognition in noise

Guest Post from Kenny Vaden:

During the holiday season, many of us will experience difficulty having conversations in noisy settings (e.g., family gatherings, restaurants, and airports). Word recognition errors and reduced signal to noise ratios (SNR) during effortful listening have been shown to elicit elevated activity in frontal regions that include the bilateral dorsal cingulate, anterior insulae, and frontal operculum (Wild et al., 2012). In an article entitled, The Cingulo-Opercular Network Provides Word-Recognition Benefit (Vaden et al., 2013), we demonstrate that this cingulo-opercular network supports speech recognition in noise on a trial-by-trial basis. This pattern of cingulo-opercular activity is thought to reflect a domain general network, which responds to task difficulty and errors for a variety of perceptual and cognitive tasks (Dosenbach et al., 2006).

Cingulo-opercular network activity is thought to reflect adaptive control functions that guide behavior. Consistent with this  premise, physiological evidence for adaptive control is found in activity that precedes behavior. Importantly, elevated cingulo-opercular activity has been associated with behavioral adjustments on the next trial for visuo-spatial tasks (Carter et al., 2000; Kerns et al., 2004; Weissman, Roberts, Visscher, & Woldorff, 2006). We asked whether similar results would be observed for word recognition in noise. In each trial of our fMRI experiment, participants were instructed to repeat a CVC word that was presented in a background of multitalker babble (energetic masking with ten voices; blocks consisted of 4-6 trials with +3 or +10 dB SNR). Word recognition was more likely for trials that immediately followed high cingulo-opercular activity compared to low activity. This effect was not specific to the magnitude of dorsal cingulate activity, as a word was more likely to be recognized when all of the cingulo-opercular regions exhibited elevated activity (Vaden et al., 2013).

One implication of our findings is that limited engagement of the cingulo-opercular network could account for word recognition difficulties, especially in challenging listening conditions. For example, Brownsett and colleagues (2013) demonstrated that cingulo-opercular activity across noisy speech recognition conditions was strongly related to individual differences in post-stroke picture naming abilities for patients with aphasia. We agree with the authors’ conclusion that there is potential value in developing methods that would enhance the function of a domain general cingulo-opercular network as part of a multi-pronged approach to addressing communication impairments. More broadly, these types of adaptive control results should direct our attention to the role of domain general systems in language studies.

Brownsett, S. L. E., Warren, J. E., Geranmayeh, F., Woodhead, Z., Leech, R., & Wise, R. J. S. (2013). Cognitive control and its impact on recovery from aphasic stroke. Brain. doi:10.1093/brain/awt289
Carter, C. S., Macdonald, A. M., Botvinick, M., Ross, L. L., Stenger, V. A., Noll, D., & Cohen, J. D. (2000). Parsing executive processes: strategic vs. evaluative functions of the anterior cingulate cortex. Proc Natl Acad Sci USA, 97(4), 1944–8.
Dosenbach, N. U. F., Visscher, K. M., Palmer, E. D., Miezin, F. M., Wenger, K. K., Kang, H. C., … Petersen, S. E. (2006). A core system for the implementation of task sets. Neuron, 50(5), 799–812.
Kerns, J. G., Cohen, J. D., MacDonald, A. W., Cho, R. Y., Stenger, V. A., & Carter, C. S. (2004). Anterior cingulate conflict monitoring and adjustments in control. Science, 303, 1023–1026.
Vaden, K., Kuchinsky, S., Cute, S., Ahlstrom, J., Dubno, J., & Eckert, M. (2013). The Cingulo-Opercular Network Provides Word-Recognition Benefit. J Neurosci, 33(48), 18979–18986.
Weissman, D. H., Roberts, K. C., Visscher, K. M., & Woldorff, M. G. (2006). The neural bases of momentary lapses in attention. Nat Neuro, 9(7), 971–978.
Wild, C. J., Yusuf, A., Wilson, D. E., Peelle, J. E., Davis, M. H., & Johnsrude, I. S. (2012). Effortful listening: the processing of degraded speech depends critically on attention. J Neurosci, 32(40), 14010–14021.

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