Temporal dynamics of spike trains in the raphe nuclei during urethane sub-states in rats

RUIZ JULIETA; DIEGO MATEOS; RODRIGUEZ A.; DEVERA A.; RIVAS M; JOAQUÍN GONZÁLEZ; PABLO TORTEROLO; CLAUDIA PASCOVICH

Bilbao

Conferencia; Conference on Dynamical Systems Applied to Biology and Natural Sciences (DSABNS 2022); 2022

BCAM

Neurons of the dorsal and median raphe nuclei (DRN and MnR, respectively) playa key role in the regulation of the sleep-wake cycle [1]; nevertheless, the dependenceof their neuronal dynamic on the state remains uncharacterized. The present study aimsto estimate the entropy rate using binary Lempel-Ziv complexity (LZC) [2] for spiketrains (LZC ST) and for interspike intervals (LZC ISI bin), as well as to determine thefiring rate (FR), coefficient of variation (CV) and Lempel-Ziv complexity for interspikeintervals discretized by ordinal patterns (LZC ISI OP), of raphe neurons in two differenturethane-induced brain sub-states in rats (n = 64): active or ?REM-like? and slow waveor ?SWS-like? (SW) [3]. The hypothesis was that the complexity at the neuronal levelwould be lower during SW state [4]. For statistical analysis, multilevel linear models werebuilt using rats as a random effect and the state as a fixed effect. The different variableswere tested comparing active and SW state groups. As Figure 1 shows, the LZC ST wassignificantly higher in the active state compared with the SW state (0.084 ± 1.2 × 10 −3vs 0.080 ± 1.7 × 10 −3 mean ± SD; n = 91/156; p < 0.05). The FR of the neurons wasalso significantly higher during the active state (14.30 ± 1.98 vs 9.68 ± 1.98; p < 0.01).However, LZC ISI OP, LZC ISI bin and CV, were not significantly different between bothgroups (0.69 ± 3.6 × 10 −3 vs 0.69 ± 4.3 × 10 −3 , p = 0.27; 1.049 ± 8.9 × 10−3 vs1.041 ± 11.1 × 10 −4 ; p = 0.48; 0.53 ± 0.06 vs 0.60 ± 0.05; p = 0.20, respectively). Weconclude that a lower complexity during SW state is only captured when using LZC ST.