Activation of thalamo-cortical circuits with posterior hypothalamic nucleus deep brain stimulation
Bibliographic record
Abstract
Abstract The posterior hypothalamic nucleus (PH) has extensive anatomical connections to motor, cognitive, visceral, and homeostatic areas of the brain and serves as a crucial subcortical modulator of behaviour. Previous studies have demonstrated that deep brain stimulation (DBS) of this area can lead to powerful activation of motor behaviour, overcoming two rodent models of parkinsonian akinesia by increasing neocortical excitability. However, it is unclear how the PH may mediate this increase in neocortical excitability. In the present study, we examined the role of the thalamus in the PH-DBS mediated increase in neocortical excitability. In urethane anaesthetized animals, we demonstrate that PH-DBS elicits increased spiking activity in the motor thalamus (VL) that receives direct afferents from the PH that precedes the increase in spiking activity in the corresponding motor cortex. In contrast, in the somatosensory thalamus (VPM) where PH afferents are sparse at best, PH-DBS did not elicit an increase in thalamic activity despite of a slight increase in the corresponding somatosensory cortical spiking. Current source density analyses suggest a thalamo-cortical mechanism for motor cortex activation whereas a cortico-cortical activation mechanism is involved in somatosensory cortical activation. Inactivation of the VL resulted in the abolition of motor cortex spiking despite of the persistence of desynchronized field potential activity. Collectively, these data suggest indirect orthodromic activation of PH output fibres to the thalamus mediates increased neocortical excitation, which may spread through cortico-cortical connections and lead to an increase in integrated, non-stereotypical motor behaviour.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".