Discussion
We investigated the occurrence of sleep spindles and ripples in the human anterior and mediodorsal thalamus and those associations with epilepsy characteristics and general intelligence. Sleep spindles were detected both in the ANT and MD. The occurrence of sleep spindles in the human ANT were confirmed in previous studies (Tsai et al. 2010). We demonstrated that spindles are also present in the human MD. The duration of slow and fast spindles was similar in the two thalamic nuclei, however the overall density of fast sleep spindles was lower in the MD compared to the ANT. In the majority of cases where thalamic-scalp sleep spindle co-occurrences were detected, ANT and MD sleep spindles slightly lagged behind cortical ones, which coheres with available reports (Tsai et al. 2010) and suggests the prevailing role of corticofugal fibers in the herein studied phenomena. In a recent study, Bastuji et al. (2020) recorded sleep spindles from different parts of the posterior thalamus. These results indicate that anterior, mediodorsal and posterior thalamic nuclei are involved in the proper functioning of the NREM sleep-related thalamo-cortical network generating mid-frequency oscillations in the burst-firing mode.