TY - JOUR T1 - Selective effects of arousal on population coding of natural sounds in auditory cortex JF - bioRxiv DO - 10.1101/2020.08.31.276584 SP - 2020.08.31.276584 AU - Charles R. Heller AU - Zachary P. Schwartz AU - Daniela Saderi AU - Stephen V. David Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/12/17/2020.08.31.276584.1.abstract N2 - The ability to discriminate between complex natural sounds is critical for survival. Changes in arousal and other aspects of behavioral state can impact the accuracy of sensory coding, affecting both the reliability of single neuron responses and the degree of correlated noise between neurons. However, it is unclear how these effects interact to influence coding of diverse natural stimuli. We recorded the spiking activity of neural populations in primary auditory cortex (A1) evoked by a large library of natural sounds while monitoring changes in pupil size as an index of arousal. Heightened arousal increased response magnitude and reduced noise correlations between neurons, improving coding accuracy on average. Rather than suppressing shared noise along all dimensions of neural activity, the change in noise correlations occurred via coherent, low-dimensional modulation of response variability in A1. The modulation targeted a different group of neurons from those undergoing changes in response magnitude. Thus, changes in response magnitude and correlation are mediated by distinct mechanisms. The degree to which these low-dimensional changes were aligned with the high-dimensional natural sound-evoked activity was variable, resulting in stimulus-dependent improvements in coding accuracy.Competing Interest StatementThe authors have declared no competing interest.Discrimination/signal axis (Δμ)Vector connecting the mean population response to stimulus A and stimulus B.Pooled noise dataAll single trial data after subtracting off mean stimulus responses from each neuron.Global noise axisFirst principal component of pooled noise data.Correlated variability axis (e1)Stimulus-pair specific estimate of noise axis. First principal component of noise data pooled across the two stimuli within dDR space.Optimal decoding axis (wopt)Axis orthogonal to the optimal linear discrimination boundary in dDR space.Discrimination axis magnitude (|Δμ|)Vector magnitude of the discrimination axis.Noise interference (| cos(θe1,Δμ)|)Cosine similarity between the correlated variability axis and discrimination axis. ER -