Neural Substrates of Learning

人类和动物每天学习的许多东西都是建立在两个事件之间的简单联系之上的。人类学会避免热炉子；门铃响表示有客人，猫学习接近开罐器的声音，以期待收到食物，这只是几个例子。这些事件通过视觉、听觉、躯体感觉、嗅觉和味觉5种主要的通道特异性通路进入神经系统。这些模式中的每一个都记录了非常不同的刺激，并且都有一个独特的神经输入系统。跨不同模式的学习是否需要与输入类型相同数量的神经回路？也许有位于中枢的神经回路取决于正在处理的全局信息的类型，而不是取决于单个感觉通道？如果要学习类似的运动反应，可能会使用相同的神经学习电路。简单联想的行为参数，即经典的条件反射，其中一个刺激预测另一个刺激的出现，已经被很好地计算出来了。通过损伤、解剖追踪和神经元记录研究，已经从输入到输出验证了两种特定类型的经典条件反射的神经基础，即眨眼和恐惧对声音刺激的条件反射。眨眼调节类似于肢体屈曲调节。当使用来自样本通道的线索时，对于类似类型的经典条件反射，神经元学习电路有多相似？当使用来自不同模式的提示时，这些不同的输入是否会聚在一个共同的电路上，用于特定运动反应的经典条件反射？拟议的研究目的有两个：首先，通过测量整个大脑的葡萄糖能量代谢，绘制神经底物图，对于简单的经典条件反射范式，肢体屈曲使用常用的纯音调刺激。结果将与已知的眨眼调节电路进行比较。其次，利用视觉和躯体感觉刺激的其他形式的线索，绘制这种经典条件反射的神经基础图。许多人很难仅仅通过一种或另一种感官形式的陈述来学习。这种类型的研究可能允许识别这些类型的缺陷被修改的特定大脑区域。

Many things that humans and animals learn everyday are predicated on a simple association between two events. Humans learn to avoid hot stoves; a doorbell ringing indicates visitors, and cats learning to approach to the sound of the can opener in the anticipation of receiving food are just a few examples. These events are brought into the neural system by 5 main modality specific pathways, visual, auditory, somatosensory, olfactory and gustatory. Each one of these modalities records very different stimuli and has a unique neural input system. Does learning across different modalities require the same number of neural circuits as types of input? Perhaps there are centrally located neural circuits depending on the type of global information being processed rather than on the individual sensory modality? If similar motor responses were to be learned the same neural learning circuit might be used. The behavioral parameters of simple associative, i.e., classical conditioning, where one stimulus predicts the occurrence of another stimulus, have been well worked out. The neural substrates underlying two specific types of classical conditioning, eyeblink and fear conditioning to tone stimuli, have been verified from input to output with the use of lesion, anatomical tracing and neuronal recording studies. Eyeblink conditioning is similar to limb flexion conditioning. How similar are the neuronal learning circuits for similar types of classical conditioning when using cues from the sample modality? When using cues from different modalities, do these different inputs converge on a common circuit for classical conditioning of a particular motor response? The aim of the proposed research is two-fold: First, map the neural substrates, through measurement of glucose energy metabolism across the whole brain, for a simple classical conditioning paradigm, limb flexion using the commonly used pure tone stimulus. The results will be compared to the known circuitry for eyeblink conditioning. Second, map the neural substrates of this classical conditioned reflex using cues from additional modalities using visual and somatosensory stimuli. Many humans have difficulty learning solely by presentations made in one sensory modality or another. This type of research may allow for the identification of the specific brain regions where these types of deficits are modified.