Fig. 1.

Sleep spindles and spike and waves discharges (SWDs) of absence epilepsy. A1 Sleep spindles recorded during natural sleep from four standard EEG derivations in a normal subject during stage 2 of NREM sleep. 2 SWDs of childhood absence epilepsy. Video-EEG recordings from four standard EEG derivations in a 7-year-old girl with frequent daily absence seizures show the typical features of regular and rhythmic 3-Hz SWDs. (Reproduced with permission from Ref. [22] © Society for Neuroscience; Ref [76] © Adis International Ltd). B Schematic diagram of the thalamocortical loop. TC thalamocortical neuron, NRT nucleus reticularis thalamic neuron, + excitatory synapse, − inhibitory synapse. Dotted lines in the cortical diagram symbolize the complexity of synaptic connections between the many different cortical cell types, some of which have been omitted for clarity