Transient changes in the firing of midbrain dopamine neurons have been closely tied to the unidimensional value-based prediction error contained in temporal difference reinforcement learning models. However, whereas an abundance of work has now shown how well dopamine responses conform to the predictions of this hypothesis, far fewer studies have challenged its implicit assumption that dopamine is not involved in learning value-neutral features of reward. Here, we review studies in rats and humans that put this assumption to the test, and which suggest that dopamine transients provide a much richer signal that incorporates information that goes beyond integrated value.

The major pathological feature of Parkinson 's disease (PD), the second most common neurodegenerative disease and most common movement disorder, is the predominant degeneration of dopaminergic neurons in the substantia nigra, a part of the midbrain. Despite decades of research, the molecular mechanisms of the origin of the disease remain unknown. While the disease was initially viewed as a purely neuronal disorder, results from single-cell transcriptomics have suggested that oligodendrocytes may play an important role in the early stages of Parkinson's. Although these findings are of high relevance, particularly to the search for effective disease-modifying therapies, the actual functional role of oligodendrocytes in Parkinson's disease remains highly speculative and requires a concerted scientific effort to be better understood. This Unsolved Mystery discusses the limited understanding of oligodendrocytes in PD, highlighting unresolved questions regarding functional changes in oligodendroglia, the role of myelin in nigral dopaminergic neurons, the impact of the toxic environment, and the aggregation of alpha-synuclein within oligodendrocytes.

Understanding how corticostriatal circuits mediate behavioral selection and initiation in a naturalistic setting is critical to understanding behavior choice and execution in unconstrained situations. The central striatum (CS) is well poised to play an important role in these spontaneous processes. Using fiber photometry and optogenetics, we identify a role for CS in grooming initiation. However, CS-evoked movements resemble short grooming fragments, suggesting additional input is required to appropriately sustain behavior once initiated. Consistent with this idea, the anterior lateral motor area (ALM) demonstrates a slow ramp in activity that peaks at grooming termination, supporting a potential role for ALM in encoding grooming bout length. Furthermore, optogenetic stimulation of ALM-CS terminals generates sustained grooming responses. Finally, dual-region photometry indicates that CS activation precedes ALM during grooming. Taken together, these data support a model in which CS is involved in grooming initiation, while ALM may encode grooming bout length.

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Recent advances in the field of Voltage Imaging, with a special focus on new constructs and novel implementations.

Work related to place tuning, spatial navigation, orientation and direction. Mainly includes articles on connectivity in the hippocampus, retrosplenial cortex, and related areas.

Cerebellar transcranial direct-current stimulation (Cb-tDCS) is a promising tool for non-invasive modulation of cerebellar activity and has been proposed for the treatment of cerebellum-related disorders. However, how external currents applied to the cerebellum affect local and distant circuits remains unclear. In this study, we examined the immediate and aftereffects of Cb-tDCS on sensory inputs recorded in the cerebellar Crus I/II and primary somatosensory cortex (S1) in response to whisker stimulation. We also assessed changes in the excitation/inhibition balance using vGLUT1 and GAD 65-67 immunoreactivity. Anodal and cathodal Cb-tDCS respectively induced an immediate increase and decrease in the trigeminal component in Crus I/II but no aftereffects were observed 20 minutes post-stimulation. In S1, Cb-tDCS resulted in polarity-dependent modulation of the N1 component during stimulation, which was opposite to the changes induced in Crus I/II and a sustained increase after anodal Cb-tDCS, accompanied by reduced GAD 65-67 immunoreactivity. While power spectrum analysis revealed no changes in Crus I/II, cathodal Cb-tDCS significantly modulated gamma (30-45 Hz) and high-frequency oscillations (255-300 Hz) in S1. These findings indicate that Cb-tDCS can modulate sensory inputs during stimulation and exert delayed effects in distant cortical areas, emphasizing the need to consider both online and remote network modulation in clinical applications.

Heterozygous deletion of multiple contiguous genes associated with 22q11.2 Deletion Syndrome (22q11DS), a developmental disorder with significant risk for autistic spectrum disorder (ASD) and schizophrenia (Scz), selectively compromises neurogenic capacities of a temporally distinct cohort of cerebral cortical basal progenitors (bPs), prefiguring diminished frequency, divergent times of origin, positions, and identities of a subset of Layer 2/3 projection neuron (PN) progeny in the LgDel 22q11DS mouse model. LgDel bPs express 24/28 contiguous murine 22q11 gene orthologues at diminished levels; in parallel, cell cycle kinetics, modes of division, gene expression levels, and DNA methylation states are aberrant in LgDel bPs but not their apical progenitor precursors. Accordingly, targeted disruption of bP proliferative and transcriptional states selectively alters Layer 2/3 PN identities and frequencies, prefiguring atypical association cortico-cortical connections and behavioral deficits associated with ASD and Scz pathology in a mouse model of 22q11DS.