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 …
A 2026 systematic review found that microglia-related immune signals do not line up cleanly with psychiatric diagnosis labels: major depression showed frontolimbic TSPO-PET increases, while schizophrenia showed elevated kynurenic acid in cerebrospinal fluid.1 The strongest interpretation is that immune-brain markers may sort subgroups better than DSM categories do. Research Highlights Depression had the clearest TSPO-PET …
A 2026 juvenile rat study found that inactivating the ventral pallidum or stimulating nucleus accumbens GABA terminals in the ventral pallidum reduced social play behavior in both sexes, pointing to a specific reward-circuit pathway required for normal play expression.1 Research Highlights VP inactivation reduced play: bilateral muscimol infusion into the ventral pallidum reduced juvenile social …
A 2026 Nature study found that parasite-sensing tuft cells can release acetylcholine, activate crypt enterochromaffin cells through muscarinic receptors, trigger serotonin release, stimulate vagal afferent neurons, and suppress food intake during established infection.1 The finding is a precise gut-defense circuit, not a generic claim that the gut-brain axis explains every mood or appetite problem. Research …
A 2026 biomarker study found kynurenine-pathway activation in inflammatory major depressive disorder (MDD), but not across all depression cases. Compared with non-inflammatory MDD and healthy controls, the inflammatory subgroup had higher pathway metabolites, and omega-3 treatment reduced several of them over 8 weeks.1 Research Highlights Inflammatory depression showed kynurenine activation: people with MDD and high-sensitivity …
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 …
A 2026 PET-fMRI study of 20 healthy adults found that GABAA receptor binding tracked speech-production brain activity across frontal, temporal, parietal, putaminal, supplementary motor, and cerebellar regions, with peak GABA-BOLD correlations reaching Rs = 0.9.1 Human speech control looks less like a pure motor-output problem and more like a task-specific balance between inhibition, dopamine, and …