Listening requires selective neural processing of the incoming sound mixture, which in humans is borne out by a surprisingly clean representation of attended-only speech in auditory cortex. How this neural selectivity is achieved even at negative signal-to-noise ratios (SNR) remains unclear. We show that, under such conditions, a late cortical representation (i.e., neural tracking) of the ignored acoustic signal is key to successful separation of attended and distracting talkers (i.e., neural selectivity). We recorded and modeled the electroencephalographic response of 18 participants who attended to one of two simultaneously presented stories, while the SNR between the two talkers varied dynamically between +6 and −6 dB. The neural tracking showed an increasing early-to-late attention-biased selectivity. Importantly, acoustically dominant (i.e., louder) ignored talkers were tracked neurally by late involvement of fronto-parietal regions, which contributed to enhanced neural selectivity. This neural selectivity, by way of representing the ignored talker, poses a mechanistic neural account of attention under real-life acoustic conditions.
The paper is available here.
New paper in press in the European Journal of Neuroscience: Wöstmann et al demonstrate that the power of prestimulus alpha oscillations directly relates to confidence in pitch-discrimination
What is the mechanistic relevance of neural alpha oscillations (~10 Hz) for perception? To answer this question, we analysed EEG data from a task that required participants to compare the pitch of two tones that were, unbeknownst to participants, identical. Importantly, this task entirely removed potential confounds of varying evidence in the stimulus or varying accuracy. We found that higher prestimulus alpha power correlated with lower confidence in pitch discrimination. These results demonstrate that the relationship of prestimulus alpha power and decision confidence is direct in nature and, that it shows up in the auditory modality similar to what has been shown before in vision and somatosensation. Our findings support the view that lower prestimulus alpha power enhances neural baseline excitability.
The paper is available as preprint here.
New paper in press in JASA: Kreitewolf et al. on the role of voice-feature continuity for cocktail-party listening
Obleserlab postdoc Jens Kreitewolf is in press in The Journal of the Acoustical Society of America!
Together with our colleagues, Marc Schönwiesner (Montreal/Leipzig), Samuel Mathias (Yale), and Régis Trapeau (Montreal/Marseille), we investigated the roles of two of the most salient voice features, glottal-pulse rate (GPR) and vocal-tract length (VTL), for perceptual grouping in the cocktail party. Using carefully controlled stimuli, we show that listeners exploit continuity in both voice features to solve the cocktail-party problem, but that VTL continuity plays a stronger role for perceptual grouping than GPR continuity. Our findings are in line with the differential importance of VTL and GPR for the identification of natural talkers and have clinically relevant implications for cocktail-party listening in cochlear-implant users.
Data were recorded using the Dome at BRAMS during Jens’ ACN Erasmus Mundus exchange in Montreal.
The paper is available as preprint:
New paper in The Journal of Neuroscience: Wilsch et al.., Temporal expectation modulates the cortical dynamics of short-term memory
Congratulations to Obleserlab alumna Anna Wilsch, who is – for now – leaving academia on a true high with her latest offering on how temporal expectations (“foreknowledge” about when something is to happen) shape the neural make-up of memory!
Recorded while the Obleserlab was still in Leipzig at the Max Planck, and analysed with great input from our co-authors Molly Henry, Björn Herrmann as well as Christoph Herrmann (Oldenburg), Anna used Magnetoencephalography in an intricate but ultimately very simple sensory-memory paradigm.
While sensory memories of the physical world fade quickly, Anna here shows that this decay of short-term memory can be counteracted by temporal expectation.
Notably, spatially distributed cortical patterns of alpha (8−−13 Hz) power showed opposing effects in auditory vs. visual sensory cortices. Moreover, alpha-tuned connectivity changes within supramodal attention networks reflect the allocation of neural resources as short-term memory representations fade.
— to be updated as the paper will become available online –
New paper in Ear and Hearing: Erb, Ludwig, Kunke, Fuchs & Obleser on speech comprehension with a cochlear implant
We are excited to share the results from our collaboration with the Cochlea Implant Center Leipzig: AC postdoc Julia Erb’s new paper on how 4-Hz modulation sensitivity can inform us on 6-month speech comprehension outcome in cochlear implants.
Erb J, Ludwig AA, Kunke D, Fuchs M, & Obleser J (2018). Temporal sensitivity measured shortly after cochlear implantation predicts six-month speech recognition outcome
Now available online: