Recording Day and Night: Advice for New Investigators in the Sleep and Memory Field

Souza, Annie C.; Koike, Bruna Del Vechio; Pedrosa, Rafael; Tort, Adriano Bretanha Lopes; Queiroz, Cláudio Marcos Teixeira de; Ribeiro, Sidarta

doi:10.1016/b978-0-12-812028-6.00002-1

Cited by 3 publications

(4 citation statements)

References 94 publications

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“…Microdrives supporting 8 and 16 tetrodes were used (Souza et al, 2018). Two animals were implanted with 16-tetrode bilateral microdrives (rats 1 and 3) and the other four animals were implanted with 8-tetrode unilateral microdrives (rats 2, 4, 5, and 6).…”

Section: Methodsmentioning

confidence: 99%

Hippocampal delta oscillations entrain neuronal activity, modulate gamma amplitude and convey information about running speed on a treadmill

Furtunato

Pedrosa

Lobão-Soares

et al. 2022

Preprint

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Locomotion has long been associated with rhythmic oscillations in the rat hippocampus. Running speed and acceleration affect the spectral density at the theta (6-10 Hz) and gamma (30-150 Hz) bands and the rhythmic entrainment of neuronal activity. However, less is known about other oscillatory rhythms. Recent studies have shown that oscillatory activity in the delta (1-4 Hz) band also relates to locomotion in stationary conditions, such as running on a treadmill or in a running wheel. To further investigate the effects of stationary running on hippocampal oscillations, we recorded CA1 local field potentials and neuronal activity while rats ran at different speed protocols on a treadmill. We found a remarkable oscillatory activity at 2 Hz that was strongly modulated by running speed. Delta power and peak frequency were highest at the fastest running speed, both in constant and progressively increasing speed protocols. Delta and theta oscillations co-occurred and showed independent relationships in their instantaneous power and frequency. Moreover, the delta phase modulated the amplitude of low-gamma (20-50 Hz) oscillations and the spiking activity of putative pyramidal neurons in a speed-dependent manner. Finally, spectral components in the delta frequency range, but not theta, predicted running speed using a naive Bayes classifier. In summary, our study shows that locomotion-related delta oscillations convey information about stationary running speed and coordinate hippocampal rhythmic activity in a speed-dependent manner.

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Section: Methodsmentioning

confidence: 99%

Hippocampal delta oscillations entrain neuronal activity, modulate gamma amplitude and convey information about running speed on a treadmill

Furtunato

Pedrosa

Lobão-Soares

et al. 2022

Preprint

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“…Electrodes were designed and handmade as described elsewhere (França et al, 2020;Souza et al, 2018). The electrode arrays were designed to be implanted in the mPFC (16 channels) and the hippocampus (16 channels) according to Paxinos Atlas (Paxinos, 2013).…”

Section: Electrode Manufacturingmentioning

confidence: 99%

“…Experimental animals were subjected to surgery for electrode implantation as described in Souza et al, 2018. Briefly, anaesthesia was induced with inhaled isoflurane at 5% followed by intraperitoneal ketamine and xylazine at respective doses of 100 mg/kg and 8 mg/kg. When needed supplemental doses of ketamine and xylazine were applied to maintain anaesthesia.…”

Section: Surgery and Post-operative Animal Carementioning

confidence: 99%

5-MeO-DMT induces sleep-like LFP spectral signatures in the hippocampus and prefrontal cortex of awake rats

Souza

França

et al. 2023

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5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a potent classical psychedelic known to induce changes in locomotion, behaviour, and sleep in rodents. However, there is limited knowledge regarding its acute neurophysiological effects. Local field potentials (LFPs) are commonly used as a proxy for neural activity, but previous studies investigating psychedelics have been hindered by confounding effects of behavioural changes and anaesthesia, which alter these signals. To address this gap, we investigated acute LFP changes in the hippocampus (HP) and medial prefrontal cortex (mPFC) of freely behaving rats, following 5-MeO-DMT administration. 5-MeO-DMT led to an increase of delta power and a decrease of theta power in the HP LFPs, which could not be accounted for by changes in locomotion. Furthermore, we observed a dose-dependent reduction in slow (20-50 Hz) and mid (50-100Hz) gamma power, as well as in theta phase modulation, even after controlling for the effects of speed and theta power. State map analysis of the spectral profile of awake behaviour induced by 5-MeO-DMT revealed similarities to electrophysiological states observed during slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep. Our findings suggest that the psychoactive effects of classical psychedelics are associated with the integration of waking behaviours with sleep-like spectral patterns in LFPs.

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“…Hippocampal stereotaxic coordinates were determined based on Paxinos (2013): AP: -2.8; ML: +1.5; DV: -3.3. Surgical procedures were conducted as described in [31].…”

Section: Electrode Implantationmentioning

confidence: 99%

Experience-dependent phosphoproteomic changes in hippocampus and neocortex correlate with the abundance of spindle oscillations during the transition between SWS and REM sleep

Souza

Golbert

Cassoli

et al. 2022

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The role of sleep on memory consolidation is thought to involve experience-dependent changes in spindle oscillations and protein phosphorylation, but how these phenomena are related remains poorly understood. To gain insight into this relationship, we used electrophysiological recordings and quantitative phosphoproteomic analysis to assess spindle oscillations and phosphoprotein levels in the hippocampus (HP) and primary somatosensory cortex (S1) of adult male rats recorded across the sleep cycle. Animals were surgically implanted with multielectrode probes and after recovery were exposed or unexposed to novel objects (+ and – groups, respectively). HP and S1 samples were obtained after periods rich in either slow-wave sleep (SWS) or rapid-eye-movement sleep. Bottom-up shotgun mass spectrometry in a two-dimensional liquid chromatography-tandem mass spectrometry setup (MSE mode with label-free quantification) showed that the proteomes differed in the numbers of phosphoproteins identified by phosphoryl modification STY tags, with a total of 337 validated phosphoproteins identified in S1 and 198 in the HP. A comparison of the phosphoproteomic profiles of the treatments and regions (SWS+ versus SWS-, REM+ versus REM-, REM+ versus SWS+ and REM- versus SWS-), using clustering analysis of the significantly identified phosphoproteins, found that 51 phosphoproteins from S1 were sufficient to separate the four experimental conditions, while 37 phosphoproteins from the HP could only partially separate the groups. Fold change analysis identified 90 significantly modulated phosphoproteins related to synaptic function, actin-microtubule regulation, DNA-RNA binding, proteases-phosphatases-kinases and other regulatory functions, including CaMKII and MAPK. In both the HP and S1, nearly one third of the clustering-relevant phosphoproteins had levels significantly correlated with the abundance of spindle oscillations pooled across the transition from SWS to REM. In S1, phosphorylated Reelin was upregulated during REM compared to SWS, in proportion to the number of spindle oscillations during the transition from SWS to REM. In the HP, a voltage-gated calcium channel subunit (Cacna2d1) was down-regulated during SWS+ compared to REM+, in proportion to spindle counts. Since spindles facilitate calcium entry through the opening of voltage-dependent calcium channels, Cacna2d1 down-regulation may lead to a hippocampus-specific, REM-dependent downregulation of synaptic plasticity after exposure to novel objects. The results point to major experience-dependent differences between HP and S1 in phosphoproteomic regulation across the sleep cycle, with potential implications for memory corticalization.

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Recording Day and Night: Advice for New Investigators in the Sleep and Memory Field

Cited by 3 publications

References 94 publications

Hippocampal delta oscillations entrain neuronal activity, modulate gamma amplitude and convey information about running speed on a treadmill

Hippocampal delta oscillations entrain neuronal activity, modulate gamma amplitude and convey information about running speed on a treadmill

5-MeO-DMT induces sleep-like LFP spectral signatures in the hippocampus and prefrontal cortex of awake rats

Experience-dependent phosphoproteomic changes in hippocampus and neocortex correlate with the abundance of spindle oscillations during the transition between SWS and REM sleep

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