Cognitive and motor deficits associated with language and speech are seen in humans harboring FOXP2 mutations. The neural bases for FOXP2 mutation-related deficits are thought to reside in structural abnormalities distributed across systems important for language and motor learning including the cerebral cortex, basal ganglia, and cerebellum. In these brain regions, our prior research showed that FoxP2 mRNA expression patterns are strikingly similar between developing humans and songbirds. Within the songbird brain, this pattern persists throughout life and includes the striatal subregion, Area X, that is dedicated to song development and maintenance. The persistent mRNA expression suggests a role for FoxP2 that extends beyond the formation of vocal learning circuits to their ongoing use. Because FoxP2 is a transcription factor, a role in shaping circuits likely depends on FoxP2 protein levels which might not always parallel mRNA levels. Indeed our current study shows that FoxP2 protein, like its mRNA, is acutely downregulated in mature Area X when adult males sing with some differences. Total corticosterone levels associated with the different behavioral contexts did not vary, indicating that differences in FoxP2 levels are not likely attributable to stress. Our data, together with recent reports on FoxP2's target genes, suggest that lowered FoxP2 levels may allow for expression of genes important for circuit modification and thus vocal variability.

Astrocytes play important roles in neurological disorders such as stroke, injury, and neurodegeneration. Most knowledge on astrocyte biology is based on studies of mouse models and the similarities and differences between human and mouse astrocytes are insufficiently characterized, presenting a barrier in translational research. Based on analyses of acutely purified astrocytes, serum-free cultures of primary astrocytes, and xenografted chimeric mice, we find extensive conservation in astrocytic gene expression between human and mouse samples. However, the genes involved in defense response and metabolism show species-specific differences. Human astrocytes exhibit greater susceptibility to oxidative stress than mouse astrocytes, due to differences in mitochondrial physiology and detoxification pathways. In addition, we find that mouse but not human astrocytes activate a molecular program for neural repair under hypoxia, whereas human but not mouse astrocytes activate the antigen presentation pathway under inflammatory conditions. Here, we show species-dependent properties of astrocytes, which can be informative for improving translation from mouse models to humans.

SUMMARY Fruit flies respond to panoramic retinal patterns of visual expansion with robust steering maneuvers directed away from the focus of expansion to avoid collisions and maintain an upwind flight posture. Panoramic rotation elicits comparatively weak syndirectional steering maneuvers, which also maintain visual stability. Full-field optic flow patterns like expansion and rotation are elicited by distinct flight maneuvers such as body translation during straight flight or body rotation during hovering, respectively. Recent analyses suggest that under some experimental conditions the rotation optomotor response reflects the linear sum of different expansion response components. Are expansion and rotation-mediated visual stabilization responses part of a single optomotor response subserved by a neural circuit that is differentially stimulated by the two flow fields, or rather do the two behavioral responses reflect two distinct control systems? Guided by the principle that the properties of neural circuits are revealed in the behaviors they mediate, we systematically varied the spatial, temporal and contrast properties of expansion and rotation stimuli, and quantified the time course and amplitude of optomotor responses during tethered flight. Our results support the conclusion that expansion and rotation optomotor responses are indeed two separate reflexes, which draw from the same system of elementary motion detectors, but are likely mediated by separate pre-motor circuits having different spatial integration properties, low-pass characteristics and contrast sensitivity.

Summary Glioblastoma (GBM) metabolism has traditionally been characterized by a primary dependence on aerobic glycolysis, prompting the use of the ketogenic diet (KD) as a potential therapy. In this study we evaluated the effectiveness of the KD in GBM and assessed the role of fatty acid oxidation (FAO) in promoting GBM propagation. In vitro assays revealed FA utilization throughout the GBM metabolome and growth inhibition in nearly every cell line in a broad spectrum of patient-derived glioma cells treated with FAO inhibitors. In vivo assessments revealed that knockdown of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme for FAO, reduced the rate of tumor growth and increased survival. However, the unrestricted ketogenic diet did not reduce tumor growth and for some models significantly reduced survival. Altogether, these data highlight important roles for FA and ketone body metabolism that could serve to improve targeted therapies in GBM.

Pituitary adenylate cyclase activating polypeptide (PACAP, gene name Adcyap1) regulates a wide variety of neurological and physiological functions, including metabolism, cognition, and plays roles in of multiple forms of stress. Due to its preferential expression in nerve fibers, it has often been difficult to trace and identify the endogenous sources of the peptide in specific populations of neurons. Here, we introduce a transgenic mouse line that harbors in its genome a bacterial artificial chromosome containing an enhanced green fluorescent protein (EGFP) expression cassette inserted upstream of the PACAP ATG translation initiation codon. Analysis of expression in brain sections of these mice using a GFP antibody reveals EGFP expression in distinct neuronal perikarya and dendritic arbors in several major brain regions previously reported to express PACAP using a variety of approaches, including radioimmunoassay, in situ hybridization, and immunohistochemistry with and without colchicine. EGFP expression in neuronal perikarya was modulated in a manner similar to PACAP gene expression in motor neurons after peripheral axotomy in the ipsilateral facial motor nucleus in the brainstem, providing an example whereby the transgene undergoes proper regulation in vivo. These mice and the high-resolution map obtained are expected to be useful tools to understand anatomical patterns of PACAP expression and its plasticity in the mouse.

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Language is a complex communicative behavior unique to humans, and its genetic basis is poorly understood. Genes associated with human speech and language disorders provide some insights, originating with the FOXP2 transcription factor, a mutation in which is the source of an inherited form of developmental verbal dyspraxia. Subsequently, targets of FOXP2 regulation have been associated with speech and language disorders, along with other genes. Here, we review these recent findings that implicate genetic factors in human speech. Due to the exclusivity of language to humans, no single animal model is sufficient to study the complete behavioral effects of these genes. Fortunately, some animals possess subcomponents of language. One such subcomponent is vocal learning, which though rare in the animal kingdom, is shared with songbirds. We therefore discuss how songbird studies have contributed to the current understanding of genetic factors that impact human speech, and support the continued use of this animal model for such studies in the future.