Resting state has been established as a classical paradigm of brain activity studies, 11 mostly based on large scale measurements such as fMRI or M/EEG. This term typically refers to a 12 behavioral state characterized by the absence of any task or stimuli. The corresponding neuronal 13 activity is often called idle or ongoing. Numerous modeling studies on spiking neural networks 14 claim to mimic such idle states, but compare their results to task-or stimulus-driven experiments, 15 which might lead to misleading conclusions. To provide a proper basis for comparing physiological 16 and simulated network dynamics, we characterize simultaneously recorded single neurons' spiking 17 activity in monkey motor cortex and show the differences from spontaneous and task-induced 18 movement conditions. The resting state shows a higher dimensionality, reduced firing rates and 19 less balance between population level excitation and inhibition than behavior-related states. 20 Additionally, our results stress the importance of distinguishing between rest with eyes open and 21 closed. 22 23
2007; Fox and Raichle, 2007; van den Heuvel and Hulshoff Pol, 2010)Defined on the whole-brain 32 level, they are shaped by anatomical connectivity and derived from functional connectivity (Honey 33 et al., 2009; Bastos and Schoffelen, 2016). 34 While the exact link between the fMRI signal and neuronal activity is a matter of ongoing research 35 (Logothetis and Wandell, 2004; Ekstrom, 2010), resting state studies have also been carried out on 36 the level of single brain areas. Here, the spontaneous activity is often referred to as ongoing, intrinsic, 37 baseline, or resting state activity, and can be studied by means of, for example, optical imaging 38 combined with single electrode recordings (Arieli et al., 1996; Tsodyks et al., 1999; Kenet et al., 39 2003). Such data, collected under anesthesia, were used to investigate the variability in evoked 40 1 of 34 Manuscript submitted to eLife cortical responses (Arieli et al., 1996), the switching of cortical states (Tsodyks et al., 1999), and the 41 link of these cortical states to the underlying functional architecture (Kenet et al., 2003). In our 42 study, we aim to characterize the resting state on yet another spatio-temporal scale, namely on the 43 scale of simultaneous single unit (SU) spiking activity recorded in macaque monkey (pre-)motor cortex. 44 Spiking activity in monkey motor cortex has been studied extensively during arm movements, 45 which gives rise to an increased average neuronal firing compared to wait (Nawrot et al., 2008; 46 Rickert et al., 2009; Riehle et al., 2018). On a single unit level, direction-specific neuronal sub-47 populations encode the movement direction by firing rate modulations (Georgopoulos et al., 1986; 48 Rickert et al., 2009). These and other studies also investigated the spike time irregularity and the 49 spike count variability in monkey motor cortex during various behavioral epochs: Movements have 50 been related ...