Spectral plasticity in monkey primary auditory cortex limits performance generalization in a temporal discrimination task.
Spectral plasticity in monkey primary auditory cortex limits performance generalization in a temporal discrimination task.
复制标题
猴子初级听觉皮层的频谱可塑性限制了时间辨别任务中的表现泛化。
DOI：
10.1152/jn.00278.2020
复制
发表时间：
2020
影响因子：
2.5
通讯作者：
Vollmer,Maike
中科院分区：
文献类型：
--
作者：
Beitel,RalphE;Schreiner,ChristophE;Vollmer,Maike
听觉经验和行为训练可以改变知觉表现。然而，时间知觉学习的时间和频谱神经处理的后果仍然不清楚。具体来说，神经可塑性的属性，在行为表现的任务概括的基础仍然不确定。为了评估行为和神经可塑性之间的关系，我们评估了麻醉的猫头鹰猴的初级听觉皮层（AI）中的神经元时间处理和频谱调谐，这些猫头鹰猴被训练来辨别包络频率的增加（例如，4-Hz标准与>5-Hz目标）的正弦幅度调制（SAM）1-kHz或2-kHz载波。行为和神经元的性能泛化进行了评价，载波范围从0.5 kHz至8 kHz。心理物理阈值显示高SAM的歧视敏锐度从一个倍频程低于运营商的培训载波频率以上的0.6倍频程。然而，SAM辨别学习的泛化对于高于训练的载波频率>0.6倍频程的载波频率逐渐下降。AI中的神经反应表明，SAM辨别训练导致1）时间调制偏好增加，特别是在接近训练频率的载波上，2）具有接近训练载波频率的特征频率的神经元的频谱调谐变窄，可能限制时间训练效果的频谱泛化，以及3）奖励与非奖励SAM频率的放电率对比增强，为训练的载波频率附近的行为时间辨别提供潜在的线索。我们的研究结果表明，在特定的频谱位置的时间训练锐化局部频率调谐，因此，限制训练效果到一个狭窄的频率范围，并限制概括的时间歧视学习在更广泛的频率范围。新&值得注意的是，猴子的能力，概括幅度调制歧视非训练载波被限制在一个倍频程以下和0.6倍频程以上的训练载波频率。不对称的泛化是通过锐化皮层频谱调谐和增强的发射率之间的对比奖励和非奖励SAM刺激在载波附近的训练频率。训练刺激的频谱内容指定的频谱和时间的可塑性，可以提供一个神经基板的时间歧视学习的泛化的限制。
Auditory experience and behavioral training can modify perceptual performance. However, the consequences of temporal perceptual learning for temporal and spectral neural processing remain unclear. Specifically, the attributes of neural plasticity that underlie task generalization in behavioral performance remain uncertain. To assess the relationship between behavioral and neural plasticity, we evaluated neuronal temporal processing and spectral tuning in primary auditory cortex (AI) of anesthetized owl monkeys trained to discriminate increases in the envelope frequency (e.g., 4-Hz standard vs. >5-Hz targets) of sinusoidally amplitude-modulated (SAM) 1-kHz or 2-kHz carriers. Behavioral and neuronal performance generalization was evaluated for carriers ranging from 0.5 kHz to 8 kHz. Psychophysical thresholds revealed high SAM discrimination acuity for carriers from one octave below to ∼0.6 octave above the trained carrier frequency. However, generalization of SAM discrimination learning progressively declined for carrier frequencies >0.6 octave above the trained carrier frequency. Neural responses in AI showed that SAM discrimination training resulted in1) increases in temporal modulation preference, especially at carriers close to the trained frequency,2) narrowing of spectral tuning for neurons with characteristic frequencies near the trained carrier frequency, potentially limiting spectral generalization of temporal training effects, and3) enhancement of firing-rate contrast for rewarded versus nonrewarded SAM frequencies, providing a potential cue for behavioral temporal discrimination near the trained carrier frequency. Our findings suggest that temporal training at a specific spectral location sharpens local frequency tuning, thus, confining the training effects to a narrow frequency range and limiting generalization of temporal discrimination learning across a wider frequency range.NEW & NOTEWORTHYMonkeys’ ability to generalize amplitude modulation discrimination to nontrained carriers was limited to one octave below and 0.6 octave above the trained carrier frequency. Asymmetric generalization was paralleled by sharpening in cortical spectral tuning and enhanced firing-rate contrast between rewarded and nonrewarded SAM stimuli at carriers near the trained frequency. The spectral content of the training stimulus specified spectral and temporal plasticity that may provide a neural substrate for limitations in generalization of temporal discrimination learning.