Automatic Detection of Highly Organized Theta Oscillations in the Murine EEG

Sex- and region-specific cortical and hippocampal whole genome transcriptome profiles from control and APP/PS1 Alzheimer's disease mice

A variety of Alzheimer's disease (AD) mouse models has been established and characterized within the last decades. To get an integrative view of the sophisticated etiopathogenesis of AD, whole genome transcriptome studies turned out to be indispensable. Here we carried out microarray data collection based on RNA extracted from the retrosplenial cortex and hippocampus of age-matched, eight months old male and female APP/PS1 AD mice and control animals to perform sex- and brain region specific analysis of transcriptome profiles. The results of our studies reveal novel, detailed insight into differentially expressed signature genes and related fold changes in the individual APP/PS1 subgroups. Gene ontology and Venn analysis unmasked that intersectional, upregulated genes were predominantly involved in, e.g., activation of microglial, astrocytic and neutrophilic cells, innate immune response/immune effector response, neuroinflammation, phagosome/proteasome activation, and synaptic transmission. The number of (intersectional) downregulated genes was substantially less in the different subgroups and related GO categories included, e.g., the synaptic vesicle docking/fusion machinery, synaptic transmission, rRNA processing, ubiquitination, proteasome degradation, histone modification and cellular senescence. Importantly, this is the first study to systematically unravel sex- and brain region-specific transcriptome fingerprints/signature genes in APP/PS1 mice. The latter will be of central relevance in future preclinical and clinical AD related studies, biomarker characterization and personalized medicinal approaches.

Breeding of Cav2.3 deficient mice reveals Mendelian inheritance in contrast to complex inheritance in Cav3.2 null mutant breeding

High voltage-activated Ca_v2.3 R-type Ca²⁺ channels and low voltage-activated Ca_v3.2 T-type Ca²⁺ channels were reported to be involved in numerous physiological and pathophysiological processes. Many of these findings are based on studies in Ca_v2.3 and Ca_v3.2 deficient mice. Recently, it has been proposed that inbreeding of Ca_v2.3 and Ca_v3.2 deficient mice exhibits significant deviation from Mendelian inheritance and might be an indication for potential prenatal lethality in these lines. In our study, we analyzed 926 offspring from Ca_v3.2 breedings and 1142 offspring from Ca_v2.3 breedings. Our results demonstrate that breeding of Ca_v2.3 deficient mice shows typical Mendelian inheritance and that there is no indication of prenatal lethality. In contrast, Ca_v3.2 breeding exhibits a complex inheritance pattern. It might be speculated that the differences in inheritance, particularly for Ca_v2.3 breeding, are related to other factors, such as genetic specificities of the mutant lines, compensatory mechanisms and altered sperm activity.

Spontaneous long-term and urethane induced hippocampal EEG power, activity and temperature data from mice lacking the Cav3.2 voltage-gated Ca2+ channel

This article provides raw relative electroencephalographic (EEG) power, temperature and activity data from controls and Ca_v3.2 deficient mice. Radiotransmitter implantation was carried out in male experimental mice under ketamine/xylazine narcosis. Following a recovery period, radiotelemetric EEG recordings from the hippocampal CA1 region were obtained under spontaneous 24 h long-term conditions and post urethane injection. Relative EEG power values (%) for 2 s epochs were analysed for the following frequency ranges: delta 1 (δ1, 0.5–4 Hz), delta 2 (δ2, 1–4 Hz), theta 1 (θ1, 4–8 Hz), theta 2 (θ2, 4–12 Hz), alpha (α, 8–12 Hz), sigma (σ, 12–16 Hz), beta 1 (β1, 12–30 Hz), beta 2 (β2, 16–24 Hz), beta 3 (β3, 16–30 Hz), gamma low (γlow, 30–50 Hz), gamma mid (γmid, 50–70 Hz), gamma high (γhigh, 70–100 Hz), gamma ripples (γripples, 80–200 Hz), and gamma fast ripples (γfastripples, 200–500 Hz). In addition, subcutaneous temperature and relative activity data were analysed for both the light and dark cycle of two long-term recordings. The same type of data was obtained post urethane injection. Detailed information is provided for the age and body weight of the experimental animals, the technical specifications of the radiofrequency transmitter, the stereotaxic coordinates for the intracerebral, deep and epidural, surface EEG electrodes, the electrode features, the filtering and sampling characteristics, the analysed EEG frequency bands and the data acquisition parameters. EEG power data, temperature and activity data are available at MENDELEY DATA (doi:10.17632/x53km5sby6.1, URL: http://dx.doi.org/10.17632/x53km5sby6.1). Raw EEG data are available at zenodo (https://zenodo.org/).

Enhanced hippocampal type II theta activity AND altered theta architecture in mice lacking the Cav3.2 T-type voltage-gated calcium channel

T-type Ca²⁺ channels are assumed to contribute to hippocampal theta oscillations. We used implantable video-EEG radiotelemetry and qPCR to unravel the role of Ca_v3.2 Ca²⁺ channels in hippocampal theta genesis. Frequency analysis of spontaneous long-term recordings in controls and Ca_v3.2^-/- mice revealed robust increase in relative power in the theta (4-8 Hz) and theta-alpha (4-12 Hz) ranges, which was most prominent during the inactive stages of the dark cycles. Urethane injection experiments also showed enhanced type II theta activity and altered theta architecture following Ca_v3.2 ablation. Next, gene candidates from hippocampal transcriptome analysis of control and Ca_v3.2^-/- mice were evaluated using qPCR. Dynein light chain Tctex-Type 1 (Dynlt1b) was significantly reduced in Ca_v3.2^-/- mice. Furthermore, a significant reduction of GABA A receptor δ subunits and GABA B1 receptor subunits was observed in the septohippocampal GABAergic system. Our results demonstrate that ablation of Ca_v3.2 significantly alters type II theta activity and theta architecture. Transcriptional changes in synaptic transporter proteins and GABA receptors might be functionally linked to the electrophysiological phenotype.