McAlonan K, Brown V J, Bowman E M
School of Psychology, University of St. Andrews, St. Andrews KY16 9JU, United Kingdom.
J Neurosci. 2000 Dec 1;20(23):8897-901. doi: 10.1523/JNEUROSCI.20-23-08897.2000.
All senses, except olfaction, are routed through the thalamus to cerebral cortex. Thus, the thalamus is often referred to as the sensory gateway to cortex. Located between thalamus and cortex is a thin lamina of neurons called the thalamic reticular nucleus, which may function as an attentional gate. The phenomenon of blocking in classical conditioning provides an opportunity to test whether an attended stimulus activates the thalamic reticular nucleus more than an unattended stimulus: when a second stimulus is presented together with a previously conditioned stimulus, conditioned responding to the second stimulus is inhibited. Different groups of rats were given conditioning sessions with a single stimulus, a light or a tone, and then given conditioning sessions with compound (light and tone) stimuli. Blocking was confirmed using probe trials of single stimulus presentations. After a final test session of compound stimulus presentations, the brains were processed for the presence of Fos protein. Here we show that Fos-positive neurons were more numerous in the sector of the thalamic reticular nucleus associated with the attended conditioned stimulus than in the sector associated with the unattended stimulus. Thus, we provide evidence for an involvement of the thalamic reticular nucleus in selective attention.
除嗅觉外，所有感觉都通过丘脑传导至大脑皮层。因此，丘脑常被称为通向皮层的感觉门户。位于丘脑和皮层之间的是一层薄薄的神经元，称为丘脑网状核，它可能起到注意力闸门的作用。经典条件反射中的阻断现象提供了一个机会，来测试被关注的刺激是否比未被关注的刺激更能激活丘脑网状核：当第二个刺激与先前已形成条件反射的刺激同时呈现时，对第二个刺激的条件反应会受到抑制。给不同组的大鼠进行单一刺激（光或音）的条件反射训练，然后进行复合（光和音）刺激的条件反射训练。通过单一刺激呈现的探测试验来确认阻断现象。在复合刺激呈现的最后测试阶段后，对大脑进行处理以检测Fos蛋白的存在。我们在此表明，与被关注的条件刺激相关的丘脑网状核区域中，Fos阳性神经元比与未被关注的刺激相关的区域更多。因此，我们为丘脑网状核参与选择性注意提供了证据。
