Andersen E
Brain Res. 1986 Jun 4;375(1):30-6. doi: 10.1016/0006-8993(86)90955-8.
The response of medial thalamic neurons to noxious peripheral stimulation were studied with intracellular recording methods in the cat. Electrical stimulation of the contralateral forepaw produced an EPSP-IPSP sequence followed by rebound excitation in these medial thalamic neurons. Action potentials appeared with the initial EPSP or with the rebound excitation. The mean latency to onset was 15 ms for the EPSP and 33 ms for IPSP. In contrast, electrical stimulation of the PAG or of the pericruciate cerebral cortex produced large IPSPs in the medial thalamic neurons. When PAG or cortex stimulation were paired with noxious stimulation, both the PAG and cortex responses predominated over the noxious response. This shows that the PAG and the cerebral cortex have the capabilities of influencing the responses of the medial thalamus to noxious stimulation. The medial thalamus is part of the relay system which sends information about noxious stimulation to the cerebral cortex where the noxious information reaches conscious awareness, so influencing the message at the level of the medial thalamus would probably alter the conscious perception of pain. The data suggest the existence of an ascending pain modulation system from the midbrain to the thalamus and also suggests a mechanism of cortical control over pain perception.
采用细胞内记录方法，在猫身上研究了丘脑内侧神经元对伤害性外周刺激的反应。对猫的对侧前爪进行电刺激，在这些丘脑内侧神经元中产生了兴奋性突触后电位-抑制性突触后电位序列，随后是反弹兴奋。动作电位出现在最初的兴奋性突触后电位或反弹兴奋时。兴奋性突触后电位开始的平均潜伏期为15毫秒，抑制性突触后电位为33毫秒。相比之下，刺激中脑导水管周围灰质（PAG）或中央旁大脑皮层，在丘脑内侧神经元中产生了大的抑制性突触后电位。当PAG或皮层刺激与伤害性刺激配对时，PAG和皮层的反应均超过伤害性反应。这表明PAG和大脑皮层有能力影响丘脑内侧对伤害性刺激的反应。丘脑内侧是中继系统的一部分，该系统将有关伤害性刺激的信息发送到大脑皮层，在那里伤害性信息达到意识层面，因此在丘脑内侧水平影响该信息可能会改变对疼痛的意识感知。这些数据表明存在从中脑到丘脑的上行疼痛调制系统，也提示了皮层对疼痛感知的控制机制。
