المؤلفون: Froemke, Robert C, Carcea, Ioana, Barker, Alison J, Yuan, Kexin, Seybold, Bryan A, Martins, Ana Raquel O, Zaika, Natalya, Bernstein, Hannah, Wachs, Megan, Levis, Philip A, Polley, Daniel B, Merzenich, Michael M, Schreiner, Christoph E

المصدر: Nature Neuroscience. 16(1)

مصطلحات موضوعية: Biomedical and Clinical Sciences, Neurosciences, Clinical Sciences, Basic Behavioral and Social Science, Behavioral and Social Science, Acoustic Stimulation, Anesthetics, Animals, Auditory Cortex, Auditory Perception, Basal Nucleus of Meynert, Biophysics, Brain Mapping, Computer Simulation, Excitatory Postsynaptic Potentials, Female, Food Deprivation, Models, Neurological, Neurons, Nonlinear Dynamics, Patch-Clamp Techniques, Psychoacoustics, Rats, Sprague-Dawley, Recognition, Psychology, Signal Detection, Psychological, Statistics, Nonparametric, Synapses, Psychology, Cognitive Sciences, Neurology & Neurosurgery, Biological psychology

الوصف: Synapses and receptive fields of the cerebral cortex are plastic. However, changes to specific inputs must be coordinated within neural networks to ensure that excitability and feature selectivity are appropriately configured for perception of the sensory environment. We induced long-lasting enhancements and decrements to excitatory synaptic strength in rat primary auditory cortex by pairing acoustic stimuli with activation of the nucleus basalis neuromodulatory system. Here we report that these synaptic modifications were approximately balanced across individual receptive fields, conserving mean excitation while reducing overall response variability. Decreased response variability should increase detection and recognition of near-threshold or previously imperceptible stimuli. We confirmed both of these hypotheses in behaving animals. Thus, modification of cortical inputs leads to wide-scale synaptic changes, which are related to improved sensory perception and enhanced behavioral performance.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/88d0k8khTest

المؤلفون: Teschner, Magnus J.^1,2, Seybold, Bryan A.¹, Malone, Brian J.¹, Hüning, Jana², Schreiner, Christoph E.¹ chris@phy.ucsf.edu

المصدر: Journal of Neuroscience. 3/2/2016, Vol. 36 Issue 9, p2743-2756. 14p.

مصطلحات موضوعية: *SIGNAL-to-noise ratio, *ACOUSTIC signal processing, *SIGNAL detection, *AUDITORY cortex, *BANDWIDTHS

مستخلص: The neural mechanisms that support the robust processing of acoustic signals in the presence of background noise in the auditory system remain largely unresolved. Psychophysical experiments have shown that signal detection is influenced by the signal-to- noise ratio (SNR) and the overall stimulus level, but this relationship has not been fully characterized. We evaluated the neural representation of frequency in rat primary auditory cortex by constructing tonal frequency response areas (FRAs) in primary auditory cortex for different SNRs, tone levels, and noise levels. We show that response strength and selectivity for frequency and sound level depend on interactions between SNRs and tone levels. At low SNRs, jointly increasing the tone and noise levels reduced firing rates and narrowed FRA bandwidths; at higher SNRs, however, increasing the tone and noise levels increased firing rates and expanded bandwidths, as is usually seen for FRAs obtained without background noise. These changes in frequency and intensity tuning decreased tone level and tone frequency discriminability at low SNRs. By contrast, neither response onset latencies nor noise-driven steady-state firing rates meaningfully interacted with SNRs or overall sound levels. Speech detection performance in humans was also shown to depend on the interaction between overall sound level and SNR. Together, these results indicate that signal processing difficulties imposed by high noise levels are quite general and suggest that the neurophysiological changes we see for simple sounds generalize to more complex stimuli. [ABSTRACT FROM AUTHOR]