A 2026 rat study found that foot-shock stress transiently reduced food-cue approach during the first 2 conditioned-stimulus trials (t = 2.807; P < 0.05), and inhibiting the nucleus of the solitary tract weakened that stress effect.1 The useful finding is selective: stress used an NTS-linked route to dampen cue-evoked VTA dopamine, while outcome-specific satiety reduced ...
A 2025 iScience study found that nighttime caffeine increased motor impulsivity in Drosophila, with dose-dependent loss-of-inhibition events across n = 30-32 flies per behavioral condition and stronger effects in female flies than male flies.1 The result does not prove that an evening coffee makes humans reckless, but it sharpens a neglected point: caffeine’s alertness benefit …
A 2026 Nature Neuroscience study from the Igarashi lab proposes a circuit-level answer for why the lateral entorhinal cortex (LEC) is the first cortical region to falter in Alzheimer’s: dopamine inputs from the VTA and substantia nigra to the LEC go functionally silent at the earliest disease stage in an APP knock-in mouse — before …
Restless legs syndrome (RLS) and opioid-withdrawal restlessness both produce night-worsening urges to move. A 2026 npj Parkinson’s Disease mouse study tied that overlap to hypersensitive striatal D1-mu-opioid receptor signaling in basal-ganglia motor circuits.1 Research Highlights 2 clinically similar states converged: restless legs syndrome and opioid-withdrawal restlessness both point toward a striatal D1-mu-opioid circuit that regulates …
A 2026 iScience study recorded 27 substantia nigra neurons during deep-brain-stimulation surgery in 11 Parkinson’s disease patients and found that prior reward shaped both putative dopamine-neuron firing and the next reaction time: responses were faster after a +$10 outcome than after neutral or negative outcomes (0.916 s vs. 1.017 s, p = 0.0175).1 Research Highlights …
A 2026 Parkinson’s disease study used gene-expression data and genome-scale metabolic modeling to predict patient-level metabolite patterns, then separated 104 patients into 3 metabolic subgroups that were partly reproduced in an independent 81-patient validation dataset. Research Highlights Patient-level modeling found heterogeneity: Abdik et al. predicted secretion tendencies for 802 analyzable metabolites across 104 postmortem substantia …
Chronic stress is a candidate mechanism for both depression and addiction risk. A 2026 mouse study found that 28 days of unpredictable chronic mild stress increased striatal dopamine D1 receptor binding by 22–48% across nearly every region examined, plus more selective D2 receptor increases — pointing to a stress-driven shift in reward signaling that may …