Brain Structure & Function最新文献

Acomys cahirinus is an increasingly utilized model in various biological disciplines, particularly for studying the regeneration and developmental plasticity of the central nervous system due to its remarkable ability for neural tissue repair and early neurodevelopmental milestones. Despite its growing prominence in neuroscience, the lack of comprehensive neuroanatomical data hinders precise experimental design, especially in injury and regeneration studies. To address this gap, we present a neuroanatomical and neurochemical atlas of the Acomys cahirinus spinal cord, integrating anatomical, cytoarchitectonic, neurochemical, and morphometric data. The atlas includes: (1) a scheme depicting the relative positions of the vertebrae and spinal segments for precise access during experimental interventions; (2) mapping of neuronal populations within the spinal laminae and nuclei expressing various neurochemical markers, including NeuN, calbindin 28 kDa, calretinin, choline acetyltransferase, nitric oxide synthase, and non-phosphorylated neurofilaments (SMI-32); and (3) transverse stereotaxic maps outlining white matter and gray matter along with their laminae and nuclei, providing a reference for spatial analysis of the spinal cord. Images from the spinal cord atlas are available in the Supplementary materials.

The superior temporal sulcus (STS) plays a central role in auditory and linguistic processing and undergoes rapid development during the last trimester of gestation. Yet, the extent to which its development is shaped by early sensory experience remains unclear. Premature birth offers a unique opportunity to address this question, as it exposes the brain to an extra-uterine auditory environment at a critical stage of network maturation. We analyzed resting-state fMRI data in 116 neonates (63 males), scanned at term-equivalent age but born at varying gestational age (24.3 to 41.7 weeks gestational age) using the developing Human Connectome Project (dHCP) database. Functional connectivity was computed in native space using regions of interest based on each infant's sulcal anatomy to assess the respective contributions of STS subregions. Our analyses reveal a functional division between the inferior and superior banks of the STS, with the inferior bank showing stronger connectivity to distant parietal and frontal areas along the dorsal language pathway. The left posterior STS emerged as a functional hub, displaying broad inter-area connectivity. Longer gestations correlated with increased local connectivity, notably in the right temporal region, despite equal age at scan. Additionally, female neonates exhibited stronger connectivity from the left posterior STS compared to males. These findings highlight the early emergence of adult-like auditory-linguistic networks and their sensitivity to the in-utero environment. Further research is needed to investigate the consequences of these early differences and to determine which postnatal interventions might help compensate, if necessary.

Traumatic brain injury (TBI) is one of the most common causes of disability worldwide and a risk factor for the development of post-traumatic epilepsy and mood disorders. Sexual differences in the tissue response to the injury may contribute to the varied pathophysiology of TBI, making it particularly challenging to develop a satisfactory therapy. The aim of this study was to investigate the sexual difference in astrogliosis, microgliosis, and neuronal loss after TBI. Penetrating cortical brain injury was performed in male and female rats that were sacrificed 2, 8, 16, or 30 days after injury. Glial scar development and neuronal loss were analysed, as well as the morphology of astrocytes and microglia in perilesional cerebral cortex. Increased astrogliosis was observed in females compared to males, including more complex and hypertrophied morphology of astrocytes 2 and 8 days after TBI, an earlier onset of contralateral astrocytic reaction, and a greater GFAP + (glial fibrillary acidic protein) area fraction in perilesional cortex in females 30 days post-injury. Sex differences in microglia morphology were also observed, such as more complex and ramified microglia in females 2 and 30 days after TBI. Moreover, an increased loss of parvalbumin- and neuropeptide Y-expressing neurons in perilesional and contralateral cortex was noticed in females compared to males, along with a higher number of cells expressing neuronal nitric oxide synthase. These results suggest a sexual differences in the cellular response to traumatic brain injury, which may contribute to the different outcomes and development of post-traumatic pathologies in males and females.

Motherhood entails brain and behavioral changes associated with increased motivation for pups, ensuring their correct development and survival. Dopamine systems play a crucial role in motivated behaviors, although the exact neurobiological mechanisms underlying maternal behavior remain unknown. The tail of the ventral tegmental area (tVTA) or rostromedial tegmental nucleus (RMTg) is a control center of dopamine systems involved in avoidance and prediction error, among other brain processes. In the present study, we explored its possible contribution in maternal motivation in rats. To do so, we analyzed maternal behavior, as well as the expression of cFos in several brain regions (tVTA/RMTg, anterior-posterior VTA, shell-core ACb, mPFC, LHb, MePD, MPO) of virgin and dam rats in response to pups (Virgin-P, Dam-P) or to pup-predicting cues (absence of pups) (Virgin-NP, Dam-NP). Overall, our results reveal that maternal behavior was only displayed by dams, whereas virgins did not display maternal sensitization in our experimental conditions. Regarding the brain activity, we show that pup-predicting cues induce higher cFos in the tVTA/RMTg of pup-deprived dams compared to non-pup deprived dams and to virgin females, suggesting a role of the tVTA/RMTg in maternal reward prediction error. By contrast, pup exposure or deprivation elicit slight differences on the recruitment of other dopamine and social-related brain regions in our females. Finally, the correlation analysis of activity of brain regions mainly highlights positive correlations in pup-exposed females and scarce correlations in pup-deprived females. Overall, our results reveal a main role of the tVTA/RMTg in maternal reward prediction error.

Spinal neurons project to the vermis and the intermediate part of the hemisphere of the anterior lobe. In the posterior lobe, neurons projecting to the intermediate part, the copular part (copula pyramidis) of the paramedian lobule, differ from those projecting to the vermis in the cat. The present study by the retrograde labeling reveals that the projection patterns in copula pyramidis in the rat are similar to those identified in the cat. The projections through uncrossed ascending axons originate from (1) neurons in the medial part of laminae V and VI of the C2-T1 segments, (2) neurons in lamina V of the C7-L3 segments, (3) the marginal neurons of Clarke's column, and (4) neurons of Clarke's column of the lower thoracic and the lumbar segments. The projections through crossed ascending axons originate from (5) the lateral group of the ventral spinocerebellar tract neurons in the T12-L3 segments, (6) Stilling's sacral nuclei, and (7) the central cervical nucleus. The present findings suggest that the spinal inputs from the specific neuronal groups define the functions of copula pyramidis.

The synuclein family comprises three presynaptic proteins-alpha-synuclein (α-Syn), beta-synuclein (β-Syn), and gamma-synuclein (γ-Syn)-which are crucial for synaptic transmission. Our previous studies have detailed the precise cellular and subcellular localization of α- and β-Syn in the adult mouse retina, revealing distinct expression patterns in excitatory and inhibitory synaptic elements. The balance between excitatory and inhibitory neurotransmitters in the inner plexiform layer (IPL) is critical for neural development in the mouse retina. Here, we employed light-microscopic immunocytochemistry to investigate the expression of α- and β-Syn in the developing mouse retina, examining from embryonic day 13.5 to postnatal day 21 (E13.5, E16.5, E19.5, P1, P7, P10, P14, and P21). We revealed distinct developmental expression patterns across these stages. We found that α-Syn was first detected at E13.5, whereas β-Syn expression appeared later at E16.5. After E16.5, β-Syn exhibited a broader expression profile compared to α-Syn. Consistent with findings in the adult retina, α-Syn was confined to inhibitory synapses, while β-Syn was present in both excitatory and inhibitory synapses during development. These unique expression patterns of α- and β-Syn in the developing retina suggest potential roles in modulating excitatory and inhibitory inputs during retinal maturation. Furthermore, this research may contribute to understanding the broader role of α- and β-Syn in neural development within the central nervous system.

The complex relationship between Chinese characters and their pronunciations presents challenges for alphabetic language speakers learning Chinese. While previous studies have demonstrated brain structural alterations, little is known about functional neuroplasticity after prolonged Chinese learning. Here, we examined its impact on the resting-state functional connectivity (RSFC) associated with orthographic and phonological processing. We acquired RS-fMRI data from 17 Indian students who had learned Chinese for 3.24 years (learned group, LG) and 21 university students (control group, CG). We then selected brain regions related to Chinese orthographic and phonological processing, applied seed-based connectivity analysis to generate RSFC maps, and examined the between-group differences. We found that, compared with those in the CG, stronger RSFC in the LG was associated with the fusiform gyrus, inferior frontal gyrus (IFG), precuneus, middle occipital gyrus, insula, and cerebellum related to Chinese orthographic processing. Increased RSFC between the IFG and putamen was also observed for phonological processing in the LG. Moreover, we found a positive correlation between stronger RSFC related to orthographic processing and higher accuracy in Chinese character recognition. These findings suggest that increased neural integration between relevant functional regions plays key roles in Chinese orthography and phonology processing for alphabetic language speakers.

The ventromedial prefrontal cortex regulates both emotional and physiological processes. The infralimbic cortex (IL), a prefrontal subregion in rodents, integrates behavioral, neuroendocrine, and autonomic responses to stress. However, the organization of cortical inputs to brainstem nuclei that regulate homeostatic responses are not well defined. We hypothesized that IL projections differentially target pre-ganglionic parasympathetic neurons and adrenergic/noradrenergic nuclei. To quantify IL projections to autonomic brainstem nuclei in male rats, we utilized viral-mediated gene transfer to express yellow fluorescent protein (YFP) in IL glutamatergic neurons. YFP-positive projections to cholinergic and adrenergic/noradrenergic nuclei were then imaged and quantified. Our results indicate that IL glutamate neurons innervated the cholinergic dorsal motor nucleus of the vagus, with low projection density in the nucleus ambiguus. Furthermore, numerous DBH-positive cell groups received IL inputs. The greatest density was to the C2 and A2 regions of the nucleus of the solitary tract with intermediate levels of input to A6 locus coeruleus and throughout the C1 and A1 regions of the ventrolateral medulla. Minimal input was present in the pontine A5. Additionally, IL projections targeted the local GABAergic neurons that regulate activity within preautonomic nuclei. Collectively, our results indicate that IL pyramidal neurons project to vagal preganglionic parasympathetic neurons, presympathetic neurons of the ventrolateral medulla, as well as diffuse homeostatic modulators the nucleus of the solitary tract and locus coeruleus. Ultimately, these findings provide a roadmap for determining circuit-level mechanisms for neural control of homeostasis and autonomic balance.

Functional connectivity (FC) is a key tool for understanding the complex interactions within the human brain, highlighting connections between various regions. This study delves into the multifaceted influences shaping functional magnetic resonance imaging FC patterns during movie watching, focusing on the effects of sex, age, and movie clip. Leveraging the Human Connectome Project dataset, we systematically examine FC patterns elicited during movie watching. Notably, sex-specific variations in FC are observed, with females exhibiting heightened FC within visual, limbic, and default mode networks, while males display predominant intra-network connectivity within somatomotor and attention networks. Age-related variations further manifest, revealing FC increases with age in early adulthood (21-35 years old) within some specific networks. Moreover, our investigation unveils the profound influence of movie clips on FC patterns, with significant interactions observed between clips, sex, and age. Feature selection using the Average Cross-Session Correlation method highlights FC as distinct fingerprints of clips, and the Support Vector Machine classifier shows high accuracy (Accuracy > 0.9) when using these features. Our findings underscore the importance of considering individual demographic factors and external stimuli in understanding neural connectivity dynamics during movie-watching, with implications for both basic neuroscience research and clinical neuroimaging applications.

Acquired experiences are crucial for brain structure and function development, with a strong covariance between them. However, how experience deprivation reorganizes the covariance between structural connectivity (SC) and functional connectivity (FC), and how newly acquired experience influences this plastic reorganization remain unclear. To address these, we recruited 21 congenitally blind (CB) participants and 21 normally sighted (NS) controls. Using multi-modal MRI and graph-theoretical analyses, we examined the topological properties, and then investigated the SC-FC coupling reorganization and its relationship with braille reading ability. Compared to the NS group, the CB group showed significant topological reorganization in structural networks and disrupted intra-hemispheric SC-FC coupling. Importantly, braille reading proficiency and earlier braille onset mitigated SC-FC decoupling, suggesting that braille reading partially rescued disrupted network. Our findings highlight dynamic network plasticity in compensating for visual loss, and underscore the importance of early braille acquisition in maintaining brain networks stability in congenital blindness.