Trends in Neurosciences最新文献

Investigating the electrophysiological activity of the enteric nervous system in vivo has been an immense challenge for researchers. In a recent study, Boys, Güemes et al. developed a novel device for recording neuronal activity from the gut in live, freely moving rodents.

Flight maneuvers in the fruit fly Drosophila have long served as a model for studying principles underlying visual information processing. Advances in genetic targeting of individual types of neurons for manipulation and recording, as well as the publication of the complete connectome, have greatly expanded our knowledge of how behavior is controlled by the fly's nervous system. In this review, I summarize recent findings on how visual information relevant to flight is transformed into a behavioral output, ranging from fast stabilizing reflex-like responses to longer-lasting goal-directed behaviors. I argue that flexibility in the processing of visual information and a hierarchical recruitment of different behavioral modules enable the control of this complex behavior with a comparatively small number of neurons.

Neurons are specialized cells designed to process information and transmit it, often across long distances. In many neurons, the axonal volume far exceeds the somato-dendritic volume, creating a need for long-range transport and local polarization mechanisms. In addition, action potential firing and restoration of ionic gradients, as well as dynamic changes in synaptic plasticity, further increase the energetic demands of neurons. In this review, we highlight the roles mitochondria play in vertebrate neuronal biology and how mitochondrial functionality is tuned to support the unique demands of neurons. We cover the influence of mitochondrial positioning, ATP generation and Ca²⁺ buffering on neuronal function, and explore the role of mitochondria in neurotransmitter metabolism and local protein translation.

The diversification and expansion of distinct progenitor cell subtypes during embryogenesis are essential to form the sophisticated brain structures present in vertebrates. In particular, the emergence of highly proliferative basal progenitors contributed to the evolutionary enlargement of the mammalian neocortex. Basal progenitors are at the center of indirect neurogenesis and can be divided into two main subtypes: the classical TBR2-positive intermediate progenitor cells and the outer radial glial cells, which are especially abundant in gyrencephalic species. While the function of some transcriptomic regulators is conserved across the mammalian clade, recent studies have identified human-specific genes and enhancers that uniquely affect progenitor biology, possibly driving the increased neocortical complexity and disease-susceptibility of the human brain. Here, we review the evolution of basal progenitors, highlighting species-specific traits, molecular drivers of proliferation, and how imbalances in neurogenesis contribute to human brain disorders.

Dopamine suppresses GABA release from striatal terminals in the substantia nigra pars reticulata. Molinari et al. recently demonstrated that this suppression is frequency-dependent-instituting a high-pass filter on striatal 'direct pathway' transmission-and does not require dopamine receptors. Rather, dopamine upregulates serotonin, activating presynaptic 5HT_1B receptors to exert its effects.

Atypical phonological processing is at the core of developmental dyslexia and is linked to aberrant tracking and analysis of auditory information in the cortex. Despite the importance of these mechanisms for speech processing and linguistic development, oral language comprehension in dyslexia remains largely intact. Recent findings suggest that dyslexia-linked atypical cortical processing patterns reflect both underlying deficits and compensatory strategies. This review synthesizes recent evidence linking atypical cortical tracking of auditory information in dyslexia, language development, and neurocognitive mechanisms of adaptive and resilient speech comprehension. We propose hemispheric rebalancing of linguistic analysis as a key compensatory mechanism in dyslexia, supported by interhemispheric connectivity within the distributed bilateral language network and greater reliance on lexico-semantic features during speech processing.

Despite extensive research on hemispheric asymmetries, the mechanisms regulating lateralized brain functions are incompletely understood. Growing evidence suggests that lateralized neural circuits are side-specifically controlled, in part, by neuropeptides acting as neuromodulators, paracrine factors, and neurohormones. This review highlights evidence supporting this concept in the contexts of lateralized pain processing in the amygdala, control of auditory signaling, lateralized interoceptive signaling, and side-specific endocrine regulation. Our focus is primarily on rodent studies, with supporting data from humans and nonmammalian species, including turtles and nematodes. Left-right side-specific control may be rooted in a bipartite, lateralized organization of neuropeptide systems. Neuropeptides with asymmetric actions may act locally within specific brain regions or be coordinated across the neuraxis. These findings converge on a model in which neuropeptides enable lateralized control through interconnected mechanisms spanning gene expression, neural circuits, and behavioral outcomes.

A recent comparative transcriptomics study by Liu et al. highlights that conserved neuronal identity and synaptic gene expression in the superior colliculus of mice, tree shrews, and humans coexist with species-specific differences in primary cilia. These findings indicate that conserved circuit architecture is accompanied with specializations in signaling compartments that modulate circuit function.

Myelin formation involves massive lipid production, which requires extensive choline uptake and metabolism. Highlighting two recent studies conducted by Liu et al. and Chen et al., we discuss the identification of Slc44a1 as the primary oligodendrocyte choline transporter. These findings establish choline import as an evolutionarily conserved checkpoint for oligodendrocyte differentiation and central nervous system myelination.

The human brain's long-range axonal connections are the scaffolding for communication across functionally distinct areas. Yet knowledge of the human brain's wiring diagram remains limited, largely due to longstanding technological challenges. Recent innovations in microscopy may now enable mapping human brain connectivity at the mesoscale (groups of neurons and their axons). In this review we describe the challenges of generating the wiring diagrams of the human brain, avenues forward, and reasons why such an effort is so important. We argue for building a human mesoscale connectome via a multimodal, multi-species, axon-centric approach, focusing on where axons begin and end to reconstruct connectivity across spatial resolutions. Finally, we consider the utility of a potential exemplar connectome for both clinical applications and research.