What's that sound? Auditory area CLM encodes stimulus surprise, not intensity or intensity changes
What's that sound? Auditory area CLM encodes stimulus surprise, not intensity or intensity changes
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DOI：
10.1152/jn.01270.2007
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发表时间：
2008-06-01
影响因子：
2.5
通讯作者：
Theunissen, Frederic E.
中科院分区：
文献类型：
--
作者：
Gill, Patrick;Woolley, Sarah M. N.;Theunissen, Frederic E.
编码自然刺激的高级感觉神经元不能很好地用时变刺激强度的线性模型来描述。在这里，我们表明，放电率的神经元在一个次要的感觉前脑区可以更好地模拟线性函数的刺激是多么令人惊讶。我们仿照听觉神经元尾侧mesopallium（CLM）的成年雄性斑胸草雀乌拉坦麻醉与线性滤波器卷积不与刺激强度，但刺激惊喜。惊喜被量化为对数的概率的刺激给定的本地最近的刺激历史和期望的基础上同种歌曲。使用我们的惊喜的方法，神经反应同种歌曲的预测提高了67%，相对于那些使用刺激强度。类似的预测改进不能通过假设CLM执行导数检测来复制。惊讶的解释力从中脑到初级前脑再到CLM都在增加。当呈现的刺激是随机合成的涟漪噪声时，CLM神经元（但不是较低听觉区域的神经元）被最好地描述为好像它们期待同种歌曲，发现鸟鸣和噪声之间的不一致令人惊讶。总之，CLM神经元中的尖峰指示刺激惊喜多于它们指示刺激强度特征。刺激惊喜的概念可能是有用的建模神经反应在其他高阶感官领域的功能还知之甚少。
High-level sensory neurons encoding natural stimuli are not well described by linear models operating on the time-varying stimulus intensity. Here we show that firing rates of neurons in a secondary sensory forebrain area can be better modeled by linear functions of how surprising the stimulus is. We modeled auditory neurons in the caudal lateral mesopallium (CLM) of adult male zebra finches under urethane anesthesia with linear filters convolved not with stimulus intensity, but with stimulus surprise. Surprise was quantified as the logarithm of the probability of the stimulus given the local recent stimulus history and expectations based on conspecific song. Using our surprise method, the predictions of neural responses to conspecific song improved by 67% relative to those obtained using stimulus intensity. Similar prediction improvements cannot be replicated by assuming CLM performs derivative detection. The explanatory power of surprise increased from the midbrain through the primary forebrain and to CLM. When the stimulus presented was a random synthetic ripple noise, CLM neurons (but not neurons in lower auditory areas) were best described as if they were expecting conspecific song, finding the inconsistencies between birdsong and noise surprising. In summary, spikes in CLM neurons indicate stimulus surprise more than they indicate stimulus intensity features. The concept of stimulus surprise may be useful for modeling neural responses in other higher-order sensory areas whose functions have been poorly understood.