Dean P, Simkins M, Hetherington L, Mitchell I J, Redgrave P
Department of Psychology, University of Sheffield, England.
Brain Res Bull. 1991 Jan;26(1):1-10. doi: 10.1016/0361-9230(91)90184-l.
The rodent superior colliculus mediates a wide range of physiological and behavioural responses to sudden stimuli, including desynchronisation of the cortical electroencephalogram (EEG). To investigate how this desynchronisation is produced, one of two powerful excitatory agents, sodium L-glutamate (200 nl, 10 nmol) or bicuculline methiodide (200 nl, 40 pmol), was injected into the dorsal midbrain of sleeping rats. Microinjections at sites widely distributed throughout all layers of the superior colliculus were able to desynchronise the cortical EEG. i) In the superficial layers, bicuculline was effective at more sites than glutamate, whereas the reverse was true for the deep layers. ii) At some sites EEG desynchronisation occurred together with the defensive or orienting movements that are obtained from collicular stimulation in awake animals. At other sites cortical arousal occurred without such movements. iii) Comparison with a previous study suggested that urethane selectively blocks cortical arousal to glutamate injections in the superficial and intermediate grey layers. This evidence suggests that multiple collicular output pathways can desynchronise the cortical EEG, perhaps reflecting multiple functions for EEG desynchronisation.
啮齿动物的上丘介导对突然刺激的多种生理和行为反应，包括皮质脑电图（EEG）的去同步化。为了研究这种去同步化是如何产生的，将两种强效兴奋性药物之一，L-谷氨酸钠（200 nl，10 nmol）或甲磺酸荷包牡丹碱（200 nl，40 pmol）注射到睡眠大鼠的中脑背侧。在上丘所有层广泛分布的部位进行微量注射能够使皮质脑电图去同步化。i）在浅层，荷包牡丹碱比谷氨酸在更多部位有效，而在深层则相反。ii）在一些部位，脑电图去同步化与清醒动物从丘刺激获得的防御或定向运动同时发生。在其他部位，皮质觉醒在没有这种运动的情况下发生。iii）与先前研究的比较表明，乌拉坦选择性地阻断了浅层和中间灰质层对谷氨酸注射的皮质觉醒。这一证据表明，多个丘输出通路可以使皮质脑电图去同步化，这可能反映了脑电图去同步化的多种功能。
