2013 Schneider and Woolley 2013 Teschner et al.
The underlying neural mechanisms remain unclear, despite an increasing research focus on this fundamental problem ( Bar-Yosef and Nelken 2007 Hulse et al. 1975), suggesting that the cortex plays a central role in the processing of sounds in noise. Temporal cortex lesions render patients particularly susceptible to the effects of noise on auditory perceptual performance ( Olsen et al.
The presence of confounding noise sources can reduce the ability of humans and other animals to discriminate between sounds (e.g., Miller et al. The central auditory system must typically process behaviorally relevant sounds in the presence of competing sound sources, which act as background noise for foreground signals of interest. We identified neuronal populations in core auditory cortex of squirrel monkeys that differ in how they process foreground signals in background noise and that may contribute to robust signal representation and discrimination in acoustic environments with prominent background noise. The neural basis of robust perceptual performance in noise is not well understood. NEW & NOTEWORTHY The ability to detect and discriminate sounds in background noise is critical for our ability to communicate. These findings demonstrate significant diversity in signal in noise processing even within the core auditory fields that could support noise-robust hearing across a wide range of listening conditions. Even though the background noise level was typically not explicitly encoded in cortical responses, significant information about noise context could be decoded from cortical responses on the basis of how the neural representation of the foreground sweeps was affected. Whereas the addition of noise progressively suppressed the FM responses of some cortical sites in the core fields with decreasing signal-to-noise ratios (SNRs), the stimulus representation remained robust or was even significantly enhanced at specific SNRs in many others. We used spike train decoding techniques to determine the functional effects of a continuous white noise background on the responses of clusters of neurons in auditory cortex to foreground signals, specifically frequency-modulated sweeps (FMs) of different velocities, directions, and amplitudes. Because acoustic noise affects the synaptic background activity of cortical networks, it may improve the cortical responses to signals.
However, recent studies of neural network models and brain slices have shown that background synaptic noise can improve the detection of signals. Traditionally, noise is thought to degrade the cortical representation of sounds by suppressing responses and increasing response variability. In natural listening conditions, many sounds must be detected and identified in the context of competing sound sources, which function as background noise.
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