Cognitive and Auditory Neuroscience Laboratory (Lab 1), Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute for Biomedical Research of Salamanca (IBSAL), Spain.
Cognitive and Auditory Neuroscience Laboratory (Lab 1), Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute for Biomedical Research of Salamanca (IBSAL), Spain; Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Spain.
Hear Res. 2021 Jan;399:107997. doi: 10.1016/j.heares.2020.107997. Epub 2020 May 21.
Auditory deviance detection is a function of the auditory system that allows reduction of the processing demand for repetitive stimuli while stressing unpredictable ones, which are potentially more informative. Deviance detection has been extensively studied in humans using the oddball paradigm, which evokes an event-related potential known as mismatch negativity (MMN). The same stimulation paradigms are used in animal studies that aim to elucidate the neuronal mechanisms underlying deviance detection. In order to understand the circuitry responsible for deviance detection in the auditory cortex (AC), it is necessary to determine the properties of excitatory and inhibitory neurons separately. Measuring the spike widths of neurons recorded extracellularly from the anaesthetized rat AC, we classified them as fast spiking or regular spiking units. These two neuron types are generally considered as putative inhibitory or excitatory, respectively. In response to an oddball paradigm, we found that both types of units showed similar amounts of deviance detection overall. When considering each AC field separately, we found that only in A1 fast spiking neurons showed higher deviance detection levels than regular spiking neurons, while in the rest of the fields there was no such distinction. Interpreting these responses in the context of the predictive coding framework, we found that the responses of both types of units reflect mainly prediction error signaling (i.e., genuine deviance detection) rather than repetition suppression.
听觉偏离检测是听觉系统的一种功能，它可以减少对重复刺激的处理需求，同时强调那些可能更具信息量的不可预测刺激。偏离检测在人类中已经通过oddball 范式进行了广泛研究，该范式引发了一种称为失匹配负波（MMN）的事件相关电位。同样的刺激范式也用于旨在阐明偏离检测背后的神经元机制的动物研究中。为了了解听觉皮层（AC）中负责偏离检测的电路，有必要分别确定兴奋性和抑制性神经元的特性。通过测量从麻醉大鼠 AC 记录的细胞外神经元的尖峰宽度，我们将它们分类为快速尖峰或规则尖峰单位。这两种神经元类型通常分别被认为是假定的抑制性或兴奋性神经元。对于 oddball 范式，我们发现这两种类型的神经元在整体上都表现出相似的偏离检测量。当分别考虑每个 AC 区域时，我们发现只有在 A1 中，快速尖峰神经元显示出比规则尖峰神经元更高的偏离检测水平，而在其余区域则没有这种区别。在预测编码框架的背景下解释这些反应，我们发现这两种类型的神经元的反应主要反映了预测误差信号（即真正的偏离检测），而不是重复抑制。
