Where the Brain Detects Changes in Natural Sounds

Summary: A new study sheds light on how the brain tunes into relevant changes in natural sound to optimize behavior.

Source: SfN.

Electrical activity in a region of the parietal cortex underlies the detection of a transition between two complex sounds, finds a study of human participants published in eNeuro. The research provides insight into how the brain tunes into relevant changes in the environment to optimize behavior.

he world is filled with a multitude of ever-changing sound. While some of these sounds signal important information about the environment, such as the presence of danger, many others are not so useful. Detecting changes in a natural soundscape is essential for identifying which sounds should be attended to.

Bernhard Englitz and colleagues presented participants with random changes (or no change) between two acoustic textures resembling rain, applause or bubbling water through headphones while their brain activity was recorded using electroencephalography. The researchers found that the longer participants were exposed to the first texture, the faster their reaction time and ability to identify the changes.

graph

A. We presented natural textures which change their statistics at random times to a variable degree (depicted: 3 s). The change in statistics leads to a distributed change in spectro-temporal properties. The present example shows a transition from bubbling to a linear mixture between bubbling and rain, with an intermediate mixing coefficient of 0.3. Level is relative to the maximal overall level. B. Texture sounds were provided via headphones while simultaneously recording whole-head EEG signals from 64 channels. In the active paradigm, listeners were instructed to report whether they heard a change by pressing a button after the termination of the sound and otherwise not to respond. Instead, in the passive variant they were just asked to listen to the stimuli. NeuroscienceNews.com image is credited to Górska et al., eNeuro (2018).

Activity in the precuneus, a part of the parietal cortex near the occipital lobe, appears to be the source of these effects, which were stronger when participants were prompted to indicate whether or not they noticed a change, but also present in passive listening conditions.

About this neuroscience research article

Source: David Barnstone – SfN
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is credited to Górska et al., eNeuro (2018).
Original Research: Abstract for “Evidence Integration in Natural Acoustic Textures during Active and Passive Listening” by U. Górska, A. Rupp, Y. Boubenec, T. Celikel and B. Englitz in eNeuro. Published April 9 2018,
doi:10.1523/ENEURO.0090-18.2018

Cite This NeuroscienceNews.com Article
SfN “Where the Brain Detects Changes in Natural Sounds.” NeuroscienceNews. NeuroscienceNews, 11 April 2018.
<http://neurosciencenews.com/natural-sound-changes-8766/>.
SfN (2018, April 11). Where the Brain Detects Changes in Natural Sounds. NeuroscienceNews. Retrieved April 11, 2018 from http://neurosciencenews.com/natural-sound-changes-8766/
SfN “Where the Brain Detects Changes in Natural Sounds.” http://neurosciencenews.com/natural-sound-changes-8766/ (accessed April 11, 2018).

Abstract

Evidence Integration in Natural Acoustic Textures during Active and Passive Listening

Innate immune memory is a vital mechanism of myeloid cell plasticity that occurs in response to environmental stimuli and alters subsequent immune responses. Two types of immunological imprinting can be distinguished—training and tolerance. These are epigenetically mediated and enhance or suppress subsequent inflammation, respectively. Whether immune memory occurs in tissue-resident macrophages in vivo and how it may affect pathology remains largely unknown. Here we demonstrate that peripherally applied inflammatory stimuli induce acute immune training and tolerance in the brain and lead to differential epigenetic reprogramming of brain-resident macrophages (microglia) that persists for at least six months. Strikingly, in a mouse model of Alzheimer’s pathology, immune training exacerbates cerebral β-amyloidosis and immune tolerance alleviates it; similarly, peripheral immune stimulation modifies pathological features after stroke. Our results identify immune memory in the brain as an important modifier of neuropathology.

Trial Registration clinicaltrials.gov Identifier: NCT01407094

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