Mediodorsal thalamus and ventral pallidum contribute to subcortical regulation of the default mode network

Humans and other animals readily transition from externally to internally focused attention, and these transitions are accompanied by coactivation of a group of brain regions collectively known as the default mode network (DMN). While the DMN was considered a cortical network, recent evidence suggests subcortical structures are part of the DMN. Here we investigated the role of ventral pallidum (VP) and mediodorsal thalamus (MD) in DMN regulation in the tree shrew, a close relative of primates. We combine electrophysiology and deep learning-based motion tracking to perform unsupervised classification of behavioral states. We found gamma oscillations in VP and MD coordinated with gamma in the anterior cingulate (AC) cortex specifically during DMN states. Similar enhancements were found for high gamma, but only at subcortical sites. Cross-frequency coupling between gamma and delta oscillations were higher during DMN than other behaviors, underscoring the engagement of MD, VP, and AC circui..., Materials and methods
The local ethical committee on animal experimentation (canton of Fribourg), approved all experimental procedures.
Animals. Three adult tree shrews, T. belangeri, of either sex were housed under a 13/11 LD cycle in a 3 m3 cage with branches, some enrichment elements, and ad libitum access of food and water. The cage was connected to a nest box with a tube.
Surgical Procedures. Animals first received i.m injections of Alfaxan (40 mg/kg) to induce anaesthesia and Atropine (0.08 mg/kg) to prevent secretions. Animals were then intubated using a modified otoscope (Bebird, Alhambra, CA),  ventilated at 100 bpm (Small Animal Ventilator, Harvard Apparatus, Cambridge, MA), and placed in a stereotactic frame (David Kopf Instruments Tujunga, CA). Anaesthesia was maintained with isoflurane (1-3%) in pure oxygen, and end tidal CO2 was monitored (Physiosuite, Kent Scientific Torrington CT) and maintained at ~4%. Lidocaine (0.5 ml 1%) was injected near the incision site, a midline..., , **Variables**

**Fig1B**

Deep Lab Cut likelihood before and after relabeling of misclassified frames.

This data set contains 4 variables. Likelihood from two body parts(neck and nose) before and after relabelling misclassified frames, 12 video segments, 2400 frames each.

nk1: Neck position likelihood before relabelling misclassified frames.

nk2: Neck position likelihood after relabelling misclassified frames.

ns1: Nose position likelihood before relabelling misclassified frames.

ns2: Nose position likelihood after relabelling misclassified frames.

**Fig1C**

Scatter plot shows the likelihood before and after relabeling from 12 segments of a 4-hour session.

This data set contains 4 variables.

NK_bf: Average likelihood of neck position from each video segment before relabelling misclassified frames.

NK_af: Average likelihood of neck position from each video segment after relabelling misclassified frames.

NS_bf: Average likelihood of nose position from each video segment before ...