Erschienen in:13th Goettingen Meeting of the German Neuroscience Society, NWG2019, Goettingen, Germany, 2019-03-20 - 2019-03-23
Sprache:
Englisch
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Beschreibung:
The resting state activity is typically studied in large scale measurements such as fMRI or M/EEG with the aim to understand spontaneous brain activity as opposed to task- or stimulus-evoked. To get an insight in network activity on the level of multiple single units, we recorded the spiking activity and LFP from macaque (pre-)motor cortex during rest (i.e. without any task), using a chronically implanted 4x4 mm2 100 electrode Utah Array (Blackrock Microsystems). Based on video recordings of the monkeys, we defined epochs of resting (RS), sleepiness (RSS), spontaneous body movements (M) and contra-lateral arm movements (AM). Each recording session lasted 15-20 min and yielded approximately 140 simultaneously recorded single units, which we separated into putative inhibitory (INH) and excitatory (EXC) neurons according to their wave shape (Dehghani et al. 2016). We characterized the recorded data by their firing rates, the regularity of the firing activity (CV (global measure), LV (local measure)), the pairwise fine temporal correlations (~2 ms), rate covariances (~200 ms), and the power spectra of the LFP.We find that INH units fire faster and more regularly compared to EXC in all states, although the distributions of the LV are relatively similar. The CV, that does not account for non-stationarities, yields highest values during RSS and AM , indicating highly varying firing rates. Focusing on the characteristics of individual neurons, we find that the change of firing rates with respect to behavioral state is most prominent in inhibitory units. The firing rates of excitatory units are much less correlated to behavior. The distributions of the fine temporal correlations and the rate covariances are broader and reach higher absolute values during AM, M and RSS compared to RS. INH-INH correlations are higher than for EXC-EXC, independently of the behavioral states. Power spectra show different dominant frequencies with respect to behavioral state and monkey with increased power in alpha-beta range (7-30 Hz) during ...