Here is the abstract and my favourite figure from Malte’s paper.
Abstract
Speech comprehension in multi-talker situations is a notorious real-life challenge, particularly for older listeners. Younger listeners exploit stimulus-inherent acoustic detail, but are they also actively predicting upcoming information? And further, how do older listeners deal with acoustic and predictive information? To understand the neural dynamics of listening difficulties and according listening strategies, we contrasted neural responses in the alpha-band (~10 Hz) in younger (20−30 years, n = 18) and healthy older (60−70 years, n = 20) participants under changing task demands in a two-talker paradigm. Electroencephalograms were recorded while humans listened to two spoken digits against a distracting talker and decided whether the second digit was smaller or larger. Acoustic detail (temporal fine structure) and predictiveness (the degree to which the first digit predicted the second) varied orthogonally. Alpha power at widespread scalp sites decreased with increasing acoustic detail (during target digit presentation) but also with increasing predictiveness (in-between target digits). For older compared to younger listeners, acoustic detail had a stronger impact on task performance and alpha power modulation. This suggests that alpha dynamics plays an important role in the changes in listening behavior that occur with age. Lastly, alpha power variations resulting from stimulus manipulations (of acoustic detail and predictiveness) as well as task-independent overall alpha power were related to subjective listening effort. The present data show that alpha dynamics is a promising neural marker of individual difficulties as well as age-related changes in sensation, perception, and comprehension in complex communication situations.
Update #2
German radio broadcasterMDR Info did an interview & feature on Malte’s Experiment. Check out the stream below:
References
Wöstmann M1, Herrmann B2, Wilsch A2, Obleser J3. Neural alpha dynamics in younger and older listeners reflect acoustic challenges and predictive benefits. J Neurosci. 2015 Jan 28;35(4):1458–67. PMID: 25632123. [Open with Read]
Speech comprehension in multitalker situations is a notorious real-life challenge, particularly for older listeners. Younger listeners exploit stimulus-inherent acoustic detail, but are they also acti […]
Congratulation to PhD student Malte Wöstmann, who – with Erich Schröger and Jonas Obleser – has a new article in press at the Journal of Cognitive Neuroscience
forthcoming. We will update you accordingly as the paper comes online. We will share however one of Malte’s figures here as a teaser: The paper utilises a very classic component of the evoked potential, the contingent negative variation (the CNV; or a close relative thereof, see the actual paper for discussion) to study how older and younger listeners allocate their attentional resources depending on implicit cues on to-be-expected listening difficulties.
References
Wöstmann M1, Schröger E, Obleser J. Acoustic Detail Guides Attention Allocation in a Selective Listening Task. J Cogn Neurosci. 2014 Nov 12:1–13. PMID: 25390200. [Open with Read]
The flexible allocation of attention enables us to perceive and behave successfully despite irrelevant distractors. How do acoustic challenges influence this allocation of attention, and to what exten […]
In a collaboration with the University Clinic of Leipzig and Prof Dr Gesa Hartwigsen (now University of Kiel), a new paper is to appear in “Cortex”, in the forthcoming special issue on Prediction in Speech and Language, edited by Alessandro Tavano and AC alumnus Mathias Scharinger.
Increased neural activity in left angular gyrus (AG) accompanies successful comprehension of acoustically degraded but highly predictable sentences, as previous functional imaging studies have shown. However, it remains unclear whether the left AG is causally relevant for the comprehension of degraded speech. Here, we applied transient virtual lesions to either the left AG or superior parietal lobe (SPL, as a control area) with repetitive transcranial magnetic stimulation (rTMS) while healthy volunteers listened to and repeated sentences with high- vs. low-predictable endings and different noise vocoding levels. We expected that rTMS of AG should selectively modulate the predictability gain (i.e., the comprehension benefit from sentences with high-predictable endings) at a medium degradation level. We found that rTMS of AG indeed reduced the predictability gain at a medium degradation level of 4‑band noise vocoding (relative to control rTMS of SPL). In contrast, the behavioral perturbation induced by rTMS reversed with increased signal quality. Hence, at 8‑band noise vocoding, rTMS over AG vs. SPL increased the overall predictability gain. Together, these results show that the degree of the rTMS interference depended jointly on signal quality and predictability. Our results provide the first causal evidence that the left AG is a critical node for facilitating speech comprehension in challenging listening conditions.
Check it out soon!
References
Hartwigsen G1, Golombek T2, Obleser J3. Repetitive transcranial magnetic stimulation over left angular gyrus modulates the predictability gain in degraded speech comprehension. Cortex. 2014 Sep 18. PMID: 25444577. [Open with Read]
Increased neural activity in left angular gyrus (AG) accompanies successful comprehension of acoustically degraded but highly predictable sentences, as previous functional imaging studies have shown. […]
Congratulations to Obleser lab alumnus Mathias Scharinger who this week published our joint work on simultaneous fMRI–EEG in Frontiers in Human Neuroscience!
Optimal utilization of acoustic cues during auditory categorization is a vital skill, particularly when informative cues become occluded or degraded. Consequently, the acoustic environment requires flexible choosing and switching amongst available cues. The present study targets the brain functions underlying such changes in cue utilization. Participants performed a categorization task with immediate feedback on acoustic stimuli from two categories that varied in duration and spectral properties, while we simultaneously recorded Blood Oxygenation Level Dependent (BOLD) responses in fMRI and electroencephalograms (EEGs). In the first half of the experiment, categories could be best discriminated by spectral properties. Halfway through the experiment, spectral degradation rendered the stimulus duration the more informative cue. Behaviorally, degradation decreased the likelihood of utilizing spectral cues. Spectrally degrading the acoustic signal led to increased alpha power compared to nondegraded stimuli. The EEG-informed fMRI analyses revealed that alpha power correlated with BOLD changes in inferior parietal cortex and right posterior superior temporal gyrus (including planum temporale). In both areas, spectral degradation led to a weaker coupling of BOLD response to behavioral utilization of the spectral cue. These data provide converging evidence from behavioral modeling, electrophysiology, and hemodynamics that (a) increased alpha power mediates the inhibition of uninformative (here spectral) stimulus features, and that (b) the parietal attention network supports optimal cue utilization in auditory categorization. The results highlight the complex cortical processing of auditory categorization under realistic listening challenges.
References
Scharinger M1, Herrmann B1, Nierhaus T2, Obleser J1. Simultaneous EEG-fMRI brain signatures of auditory cue utilization. Front Neurosci. 2014 Jun 4;8:137. PMID: 24926232. [Open with Read]
Optimal utilization of acoustic cues during auditory categorization is a vital skill, particularly when informative cues become occluded or degraded. Consequently, the acoustic environment requires fl […]
It’s only a week ago that we updated you about Antje’s latest publication at NeuroImage. Today, there is a another one coming in; Antje’s, Malte’s & Jonas’ perspective article on cortical alpha oscillations is in press at frontiers in HUMANNEUROSCIENCE.
Listening to speech is often demanding because of signal degradations and the presence of distracting sounds (i.e., “noise”). The question how the brain achieves the task of extracting only relevant information from the mixture of sounds reaching the ear (i.e., “cocktail party problem”) is still open. In analogy to recent findings in vision, we propose cortical alpha (~10 Hz) oscillations measurable using M/EEG as a pivotal mechanism to selectively inhibit the processing of noise to improve auditory selective attention to task-relevant signals. We review initial evidence of enhanced alpha activity in selective listening tasks, suggesting a significant role of alpha-modulated noise suppression in speech. We discuss the importance of dissociating between noise interference in the auditory periphery (i.e., energetic masking) and noise interference with more central cognitive aspects of speech processing (i.e., informational masking). Finally, we point out the adverse effects of age-related hearing loss and/or cognitive decline on auditory selective inhibition. With this perspective article, we set the stage for future studies on the inhibitory role of alpha oscillations for speech processing in challenging listening situations.
References
Strauß A1, Wöstmann M2, Obleser J1. Cortical alpha oscillations as a tool for auditory selective inhibition. Front Hum Neurosci. 2014 May 28;8:350. PMID: 24904385. [Open with Read]
Listening to speech is often demanding because of signal degradations and the presence of distracting sounds (i.e., “noise”). The question how the brain achieves the task of extracting only relevant i […]
Enhanced alpha power compared with a baseline can reflect states of increased cognitive load, for example, when listening to speech in noise. Can knowledge about “when” to listen (temporal expectations) potentially counteract cognitive load and concomitantly reduce alpha? The current magnetoencephalography (MEG) experiment induced cognitive load using an auditory delayed-matching-to-sample task with 2 syllables S1 and S2 presented in speech-shaped noise. Temporal expectation about the occurrence of S1 was manipulated in 3 different cue conditions: “Neutral” (uninformative about foreperiod), “early-cued” (short foreperiod), and “late-cued” (long foreperiod). Alpha power throughout the trial was highest when the cue was uninformative about the onset time of S1 (neutral) and lowest for the late-cued condition. This alpha-reducing effect of late compared with neutral cues was most evident during memory retention in noise and originated primarily in the right insula. Moreover, individual alpha effects during retention accounted best for observed individual performance differences between late-cued and neutral conditions, indicating a tradeoff between allocation of neural resources and the benefits drawn from temporal cues. Overall, the results indicate that temporal expectations can facilitate the encoding of speech in noise, and concomitantly reduce neural markers of cognitive load.
References
Wilsch A, Henry MJ, Herrmann B, Maess B, Obleser J. Alpha Oscillatory Dynamics Index Temporal Expectation Benefits in Working Memory. Cereb Cortex. 2014 Jan 31. PMID: 24488943. [Open with Read]
Enhanced alpha power compared with a baseline can reflect states of increased cognitive load, for example, when listening to speech in noise. Can knowledge about “when” to listen (temporal expectation […]
Erb J, Obleser J. Upregulation of cognitive control networks in older adults’ speech comprehension. Front Syst Neurosci. 2013 Dec 24;7:116. PMID: 24399939. [Open with Read]
Speech comprehension abilities decline with age and with age-related hearing loss, but it is unclear how this decline expresses in terms of central neural mechanisms. The current study examined neural […]
Thalamic and parietal brain morphology predicts auditory category learning
Categorizing sounds is vital for adaptive human behavior. Accordingly, changing listening situations (external noise, but also peripheral hearing loss in aging) require listeners to flexibly adjust their categorization strategies, e.g., switch amongst available acoustic cues. However, listeners differ considerably in these adaptive capabilities. For this reason, we employed voxel-based morphometry (VBM) in our study (Neuropsychologia, In press), in order to assess the degree to which individual brain morphology is predictive of such adaptive listening behavior.