The ELG-2 Datalogger Wireless EEG system is also customizable to meet the demands of the researchers and their individual experimental needs. The standard ELG-2 Datalogger Wireless EEG set is designed to record from four channels but can be altered to record from as few as two, to as many as seven. The standard set has two screws for EEG, two silver wires for EMG, and one screw for reference and ground. If you want to record LFP activity, electrode configurations can be custom made to fit your experimental needs. Furthermore, the electrode set uses a universal 1.27 mm pitch pin and socket connector, making it easy for you to create your own electrode sets. The standard sampling frequency is 100 Hz but can be increased to 200 Hz.
In the Narikiyo, K. et al study, the authors opted to use two customized ELG-2 Datalogger Wireless EEG systems to simultaneously record from two mice. The headstage was designed to record from 5-channels with a 200 Hz sampling frequency. They created their own electrode configuration to record LFPs in the neocortex and monitor sleep/wake states with EEG and EMG recordings. Their setup included three perfluoroalkoxy-coated stainless steel wires for LFP recordings, one screw for EEG, one silver wire for EMG, and one screw for ground and reference.
To assess the role of the claustrum in the synchronous generation of widespread neocortical SW activity during sleeping and awake rest states, the authors generated a claustrum-specific Cre-expressing transgenic mouse line.
Male and female mice, one to eight months of age, were used for anatomical experiments and slice physiology to determine the neural network connectivity between the claustrum and the neocortex. Male mice, two to six months of age, were used for in vivo EEG and optogenetic experiments to assess the underlying temporal relationship between the claustrum and the neocortex with respect to SW activity.
The authors performed an in vivo loss-of-function experiment with the ELG-2 Datalogger Wireless EEG system in freely moving mice to examine the necessity of the claustrum for synchronized cortical SW generation. The Cre-positive claustral neurons were selectively ablated via AAV-mediated injection of the Cre-dependent diphtheria toxin A subunit (DTA). Control mice were injected with GFP.
The ELG-2 Datalogger Wireless EEG electrodes were surgically implanted into anesthetized mice, 2 weeks after injection. The LFP wire electrodes were implanted into the deep layers of the right prefrontal cortex (coordinates: AP: 2.5–2.8, ML: 0.5–1.5, DV: 1.0–1.5), anterior cingulate cortex (coordinates: AP: 1.0, ML: 0.5, DV: 1.3), and parietal cortex (AP: −2.0, ML: 1.5, DV: 0.4). The EEG electrode and EMG wire electrode were implanted into the left parietal cortex (AP: -2.0; ML: 2.0) and neck muscle, respectively. The electrical ground and reference electrode was implanted above the cerebellum.
Recordings were performed in the home cage under a 12-hour light/12-hour dark cycle, 6 to 12 weeks after AAV injection. Mice were acclimated to the weight and presence of the headstage with a dummy device overnight before experimentation. LFPs were recorded to detect SW activity in the deep layers of the cortex. The EEG and EMG electrodes were used to monitor the behavioral states of the mice.
The generation of a genetic neural circuit map of the claustrum’s input and output connectivity revealed widespread reciprocal connections between the Cre-expressing claustral glutamatergic neurons and cortical areas.
In vitro whole-cell patch clamp recordings during optogenetic stimulation demonstrated that photostimulation of claustral neurons evoked excitatory postsynaptic potentials in all types of neurons but predominantly drove spike responses in inhibitory interneurons.
In vivo EEG in head-fixed mice revealed that the claustral glutamatergic neurons were more active during SW periods as compared to non-SW, suggesting that the claustrum activity is more closely related to SW activity than it is to the sleep state. When combined with optogenetic stimulation, in vivo EEG revealed that claustrum-induced SW activity via photostimulation mirrors spontaneous SW activity and suggests that the claustrum can regulate SW generation in neocortical areas through the coordinated activation of inhibitory interneurons.
The recorded LFPs during the loss of function experiment with the ELG-2 Datalogger Wireless EEG system revealed that the claustral-neuron-ablated mice showed a dramatic attenuation of the SW activity during SW sleep and awake rest as compared to the control. The authors indicate that the results demonstrate the importance of the claustrum in the synchronous coordination of cortical SW activity.
Through the genetic visualization and manipulation of the Cre-expressing claustral glutamatergic neurons, the authors were able to identify the claustrum as a brain structure that can serve as the spatiotemporal mechanism that generates the synchronous neocortical SW activity during sleep and awake rest.
The use of the ELG-2 Datalogger Wireless EEG system allowed the authors to wirelessly record SW activity in the neocortex while monitoring the behavioral states of mice. This system promotes the natural behavior of animals while removing the artifacts commonly associated with traditional tethered EEG experiments. The ability to accurately and efficiently record in vivo telemetry data from freely moving animals without behavioral restrictions enables reproducible data acquisition across experiments and allows future research to build upon the established findings.
Narikiyo, K., Mizuguchi, R., Ajima, A., Shiozaki, M., Hamanaka, H., Johansen, J.P., Mori, K., Yoshihara, Y. The claustrum coordinates cortical slow-wave activity. Nature Neuroscience, 2020;23(6): 741-753. doi:10.1038/s41593-020-0625-7
Amuza Wireless Neuroscience
The traditional tethered systems do not only impose barriers in EEG experiments, they also hinder natural animal behavior and produce data artifacts during in-vivo optogenetic and fiber photometry experiments. The Amuza TeleOpto and TeleFipho systems are easy to use wireless systems, designed for reproducibility and animal comfort.