A different framework to classify preoptic and hypothalamic nuclei in reptiles.

The preoptic area and the hypothalamus are inextricably linked. Together, they represent an area of the forebrain that is essential for survival of the species. Observations in mammals have suggested a classification of these structures into four rostrocaudal areas and three mediolateral zones. Two species of crocodiles were investigated to determine if this scheme or a modification of it could be applied to these reptiles. The resulting classification identified three rostrocaudal areas based on their respective relationship to the ventricular system: preoptic, anterior, and tuberal and four mediolateral zones: ependyma, periventricular, medial, and lateral. This scheme avoided the cumbersome and complicated nomenclature that has traditionally been used for morphologic studies of these areas in other reptiles, including crocodiles. The present classification is simple, straightforward, and readily applicable to other reptiles.

High-resolution mapping and digital atlas of subcortical regions in the macaque monkey based on matched MAP-MRI and histology.

Subcortical nuclei and other deep brain structures are known to play an important role in the regulation of the central and peripheral nervous systems. It can be difficult to identify and delineate many of these nuclei and their finer subdivisions in conventional MRI due to their small size, buried location, and often subtle contrast compared to neighboring tissue. To address this problem, we applied a multi-modal approach in ex vivo non-human primate (NHP) brain that includes high-resolution mean apparent propagator (MAP)-MRI and five different histological stains imaged with high-resolution microscopy in the brain of the same subject. By registering these high-dimensional MRI data to high-resolution histology data, we can map the location, boundaries, subdivisions, and micro-architectural features of subcortical gray matter regions in the macaque monkey brain. At high spatial resolution, diffusion MRI in general, and MAP-MRI in particular, can distinguish a large number of deep brain structures, including the larger and smaller white matter fiber tracts as well as architectonic features within various nuclei. Correlation with histology from the same brain enables a thorough validation of the structures identified with MAP-MRI. Moreover, anatomical details that are evident in images of MAP-MRI parameters are not visible in conventional T1-weighted images. We also derived subcortical template "SC21" from segmented MRI slices in three-dimensions and registered this volume to a previously published anatomical template with cortical parcellation (Reveley et al., 2017; Saleem and Logothetis, 2012), thereby integrating the 3D segmentation of both cortical and subcortical regions into the same volume. This newly updated three-dimensional D99 digital brain atlas (V2.0) is intended for use as a reference standard for macaque neuroanatomical, functional, and connectional imaging studies, involving both cortical and subcortical targets. The SC21 and D99 digital templates are available as volumes and surfaces in standard NIFTI and GIFTI formats.

Morphological Analysis of the Hindbrain Glucose Sensor-Hypothalamic Neural Pathway Activated by Hindbrain Glucoprivation.

Lowered glucose availability, sensed by the hindbrain, has been suggested to enhance gluconeogenesis and food intake as well as suppress reproductive function. In fact, our previous histological and in vitro studies suggest that hindbrain ependymal cells function as a glucose sensor. The present study aimed to clarify the hindbrain glucose sensor-hypothalamic neural pathway activated in response to hindbrain glucoprivation to mediate counterregulatory physiological responses. Administration of 2-deoxy-D-glucose (2DG), an inhibitor of glucose utilization, into the fourth ventricle (4V) of male rats for 0.5 hour induced messenger RNA (mRNA) expression of c-fos, a marker for cellular activation, in ependymal cells in the 4V, but not in the lateral ventricle, the third ventricle or the central canal without a significant change in blood glucose and testosterone levels. Administration of 2DG into the 4V for 1 hour significantly increased blood glucose levels, food intake, and decreased blood testosterone levels. Simultaneously, the expression of c-Fos protein was detected in the 4V ependymal cells; dopamine ß-hydroxylase-immunoreactive cells in the C1, C2, and A6 regions; neuropeptide Y (NPY) mRNA-positive cells in the C2; corticotropin-releasing hormone (CRH) mRNA-positive cells in the hypothalamic paraventricular nucleus (PVN); and NPY mRNA-positive cells in the arcuate nucleus (ARC). Taken together, these results suggest that lowered glucose availability, sensed by 4V ependymal cells, activates hindbrain catecholaminergic and/or NPY neurons followed by CRH neurons in the PVN and NPY neurons in the ARC, thereby leading to counterregulatory responses, such as an enhancement of gluconeogenesis, increased food intake, and suppression of sex steroid secretion.

Hypothalamic Inflammation as a Potential Pathophysiologic Basis for the Heterogeneity of Clinical, Hormonal, and Metabolic Presentation in PCOS.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age. It is a heterogeneous condition characterized by reproductive, endocrine, metabolic, and psychiatric abnormalities. More than one pathogenic mechanism is involved in its development. On the other hand, the hypothalamus plays a crucial role in many important functions of the body, including weight balance, food intake, and reproduction. A high-fat diet with a large amount of long-chain saturated fatty acids can induce inflammation in the hypothalamus. Hypothalamic neurons can sense extracellular glucose concentrations and participate, with a feedback mechanism, in the regulation of whole-body glucose homeostasis. When consumed nutrients are rich in fat and sugar, and these regulatory mechanisms can trigger inflammatory pathways resulting in hypothalamic inflammation. The latter has been correlated with metabolic diseases, obesity, and depression. In this review, we explore whether the pattern and the expansion of hypothalamic inflammation, as a result of a high-fat and -sugar diet, may contribute to the heterogeneity of the clinical, hormonal, and metabolic presentation in PCOS via pathophysiologic mechanisms affecting specific areas of the hypothalamus. These mechanisms could be potential targets for the development of effective therapies for the treatment of PCOS.

Microsurgical anatomy of the amygdaloid body and its connections.

The amygdaloid body is a limbic nuclear complex characterized by connections with the thalamus, the brainstem and the neocortex. The recent advances in functional neurosurgery regarding the treatment of refractory epilepsy and several neuropsychiatric disorders renewed the interest in the study of its functional Neuroanatomy. In this scenario, we felt that a morphological study focused on the amygdaloid body and its connections could improve the understanding of the possible  implications in functional neurosurgery. With this purpose we performed a morfological study using nine formalin-fixed human hemispheres dissected under microscopic magnification by using the fiber dissection technique originally described by Klingler. In our results the  amygdaloid body presents two divergent projection systems named dorsal and ventral amygdalofugal pathways connecting the nuclear complex with the septum and the hypothalamus. Furthermore, the amygdaloid body is connected with the hippocampus through the amygdalo-hippocampal bundle, with the anterolateral temporal cortex through the amygdalo-temporalis fascicle, the anterior commissure and the temporo-pulvinar bundle of Arnold, with the insular cortex through the lateral olfactory stria, with the ambiens gyrus, the para-hippocampal gyrus and the basal forebrain through the cingulum, and with the frontal cortex through the uncinate fascicle. Finally, the amygdaloid body is connected with the brainstem through the medial forebrain bundle. Our description of the topographic anatomy of the amygdaloid body and its connections, hopefully represents a useful tool for clinicians and scientists, both in the scope of application and speculation.

Projections from the dorsomedial division of the bed nucleus of the stria terminalis to hypothalamic nuclei in the mouse.

As stressful environment is a potent modulator of feeding, we seek in the present work to decipher the neuroanatomical basis for an interplay between stress and feeding behaviors. For this, we combined anterograde and retrograde tracing with immunohistochemical approaches to investigate the patterns of projections between the dorsomedial division of the bed nucleus of the stria terminalis (BNST), well connected to the amygdala, and hypothalamic structures such as the paraventricular (PVH) and dorsomedial (DMH), the arcuate (ARH) nuclei and the lateral hypothalamic areas (LHA) known to control feeding and motivated behaviors. We particularly focused our study on afferences to proopiomelanocortin (POMC), agouti-related peptide (AgRP), melanin-concentrating-hormone (MCH) and orexin (ORX) neurons characteristics of the ARH and the LHA, respectively. We found light to intense innervation of all these hypothalamic nuclei. We particularly showed an innervation of POMC, AgRP, MCH and ORX neurons by the dorsomedial and dorsolateral divisions of the BNST. Therefore, these results lay the foundation for a better understanding of the neuroanatomical basis of the stress-related feeding behaviors.

Anatomical evidence for the efferent pathway from the hypothalamus to autonomic innervation in the anterior chamber structures of eyes.

The autonomic innervation in the anterior chamber (AC) structures might play an efferent role in neural intraocular pressure (IOP) regulation, the center of which is thought to be located in the hypothalamus. In this study, we identified the efferent pathway from the hypothalamus to the autonomic innervation in the AC structures. Retrograde trans-multisynaptic pseudorabies virus (PRV) expressing green or red fluorescent protein, PRV531 and PRV724, was injected into the right and left AC of five rats, respectively; PRV531 was injected into the right AC of another five rats, and a non-trans-synaptic tracer, FAST Dil, was injected into the right AC of five rats as a control. Fluorescence signals in autonomic ganglia,the spinal cord and the central nervous system (CNS) were observed. Seven days after FAST Dil right AC injection, FAST Dil-labeled neurons were observed in the ipsilateral autonomic ganglia, including the superior cervical ganglion, pterygopalatine ganglion, and ciliary ganglion, but not in the CNS. Four and a half days after PRV531 injection into the right AC, PRV531-labeled neurons could be observed in the ipsilateral autonomic ganglia and bilateral hypothalamus nuclei, especially in the suprachiasmatic nucleus, paraventricular nucleus, dorsomedial hypothalamus, perifornical hypothalamus and ventral mammillary nucleus. Fluorescence signals of PRV531 mainly located in the ipsilateral autonomic preganglionic nuclei (Edinger-Westphal nucleus, superior salivatory nucleus and intermediolateral nucleus), but not in sensory trigeminal nuclei. Four and a half days after PRV531 right AC injection and PRV724 left AC injection, PRV531-labeled, PRV724-labeled, and double-labeled neurons could be observed in the above mentioned bilateral hypothalamus nuclei; but few contralateral infection-involving neurons (including double-labeled neurons) could be detected in the autonomic preganglionic nuclei. Our results indicate that there exist a both crossed and uncrossed hypothalamo-pre-parasympathetic and -pre-sympathetic tracts in the efferent pathways between the bilateral hypothalamic nuclei and the autonomic innervation of the bilateral AC.

Automated diffusion-based parcellation of the hypothalamus reveals subunit-specific associations with obesity.

The hypothalamus is a small, yet highly versatile structure mainly involved in bodily functions such as control of food intake and endocrine activity. Functional anatomy of different hypothalamic areas is mainly investigated using structural MRI, validated by ex-vivo histological studies. Based on diffusion-weighted imaging (DWI), recent automated clustering methods provide robust tools for parcellation. Using data of 100 healthy adults provided by the Human Connectome Project Database, we applied DWI-based automated clustering to the hypothalamus and related microstructural properties in these hypothalamic compartments to obesity. Our results suggest that the hypothalamus can be reliably partitioned into four clusters in each hemisphere using diffusion-based parcellation. These correspond to an anterior-superior, anterior-inferior, intermediate, and posterior cluster. Obesity was predicted by mean diffusivity of the anterior-superior cluster, suggesting altered inhibition of food intake. The proposed method provides an automated hypothalamic parcellation technique based on DWI data to explore anatomy and function of hypothalamic subunits in vivo in humans.

Construction of a Mex3c Gene-Deficient Mouse Model to Study C-FOS Expression in Hypothalamic Nuclei and Observe Morphological Differences in Embryonic Neural Tube Development.

BACKGROUND This study utilized CRISPR/Cas9 gene editing technology to construct a Mex3c gene-deficient mouse model, and studied C-FOS expression in hypothalamic nuclei. MATERIAL AND METHODS Thirty Mex3c-/+ mice, 30 mice in the normal group, and 30 Mex3c-/+ mice were randomly divided into control, leptin, and ghrelin groups according to different intraperitoneal injections. HE and Nissl staining were performed to observe the morphology of hypothalamic nerve cells. The C-FOS expression in hypothalamic nuclei of each group was analyzed by immunohistochemical techniques. HE staining was used to observe neural tube morphology, and LFB staining was used to observe nerve myelin sheath morphology. TEM was used to observe neuronal ultrastructure and immunohistochemical techniques were utilized to analyze nestin expression. RESULTS C-FOS expression was lower in the normal control group than in the leptin and ghrelin groups. The Mex3c control group and the leptin group had higher C-FOS expression than the ghrelin group. In neural tube studies, no significant differences were found in the neural tube pathological sections of E14.5-day embryos in each group. Nestin results demonstrated lower expression in the normal group and there was little difference between the HD and Mex3c groups. CONCLUSIONS Mex3c appears to participate in the regulation of energy metabolism by inducing C-FOS expression in the hypothalamus. The neural tubes of the offspring of Mex3c-/+ mice had defects during development.

Unexplained repeated pregnancy loss is associated with altered perceptual and brain responses to men's body-odor.

Mammalian olfaction and reproduction are tightly linked, a link less explored in humans. Here, we asked whether human unexplained repeated pregnancy loss (uRPL) is associated with altered olfaction, and particularly altered olfactory responses to body-odor. We found that whereas most women with uRPL could identify the body-odor of their spouse, most control women could not. Moreover, women with uRPL rated the perceptual attributes of men's body-odor differently from controls. These pronounced differences were accompanied by an only modest albeit significant advantage in ordinary, non-body-odor-related olfaction in uRPL. Next, using structural and functional brain imaging, we found that in comparison to controls, most women with uRPL had smaller olfactory bulbs, yet increased hypothalamic response in association with men's body-odor. These findings combine to suggest altered olfactory perceptual and brain responses in women experiencing uRPL, particularly in relation to men's body-odor. Whether this link has any causal aspects to it remains to be explored.

Automated segmentation of the hypothalamus and associated subunits in brain MRI.

Despite the crucial role of the hypothalamus in the regulation of the human body, neuroimaging studies of this structure and its nuclei are scarce. Such scarcity partially stems from the lack of automated segmentation tools, since manual delineation suffers from scalability and reproducibility issues. Due to the small size of the hypothalamus and the lack of image contrast in its vicinity, automated segmentation is difficult and has been long neglected by widespread neuroimaging packages like FreeSurfer or FSL. Nonetheless, recent advances in deep machine learning are enabling us to tackle difficult segmentation problems with high accuracy. In this paper we present a fully automated tool based on a deep convolutional neural network, for the segmentation of the whole hypothalamus and its subregions from T1-weighted MRI scans. We use aggressive data augmentation in order to make the model robust to T1-weighted MR scans from a wide array of different sources, without any need for preprocessing. We rigorously assess the performance of the presented tool through extensive analyses, including: inter- and intra-rater variability experiments between human observers; comparison of our tool with manual segmentation; comparison with an automated method based on multi-atlas segmentation; assessment of robustness by quality control analysis of a larger, heterogeneous dataset (ADNI); and indirect evaluation with a volumetric study performed on ADNI. The presented model outperforms multi-atlas segmentation scores as well as inter-rater accuracy level, and approaches intra-rater precision. Our method does not require any preprocessing and runs in less than a second on a GPU, and approximately 10 seconds on a CPU. The source code as well as the trained model are publicly available at https://github.com/BBillot/hypothalamus_seg, and will also be distributed with FreeSurfer.

Programación fetal / Fetal programming

El término Origen Temprano de las Enfermedades del Adulto explica la aparición temprana de las condiciones anormales cardiovasculares y metabólicas en la vida adulta, mayor riesgo de morbilidad y muerte asociados a factores ambientales, especialmente nutricionales, que actúan en las primeras etapas de la vida. Estas respuestas programadas dependen de la naturaleza del estímulo o noxa, del tiempo de exposición y del momento de ocurrencia de la noxa, pudiendo un solo genotipo original varios fenotipos y estarían condicionadas por criterios críticos en los cuales se desarrollarían cambios a largo plazo pudiendo ser reversibles o no. La Programación Fetal explica que respuestas adaptativas embrionarias y fetales en un ambiente subóptimo genera consecuencias adversas permanentes. La desnutrición, así como la sobrenutrición fetal aumenta el riesgo de desarrollar alteraciones en el peso y composición corporal fetal, y posteriormente obesidad, síndrome metabólico, incremento en la adiposidad, alteración en el metabolismo de la glucosa y / o insulina, alteración del metabolismo lipídico, alteraciones hepáticas y de las cifras tensionales. La impronta genómica es esencial para el desarrollo y defectos en la misma puede originar alteraciones de la identidad parental transmisibles a las siguientes generaciones. Esta programación fetal puede ser explicada por la epigenética, definida como la serie de alteraciones hereditarias de la expresión genética a través de modificaciones del ADN y las histonas centrales sin cambios en la secuencia de ADN. Estas modificaciones epigenéticas alteran la estructura y condensación de la cromatina, afectando la expresión del genotipo y fenotipo. Este artículo desarrolla los aspectos involucrados en la Programación Fetal y los posibles mecanismos sobre la misma(AU)

The term Early Origin of Adult Diseases explains the early onset of abnormal cardiovascular and metabolic conditions in adult life, increased risk of morbidity and death associated with environmental factors, especially nutritional factors, that act in the early stages of life. These programmed responses depend on the nature of the stimulus or noxa, the time of exposure and the moment of occurrence of the noxa, with a single original genotype being able to have several phenotypes and would be conditioned by critical criteria in which long-term changes could develop, reversibles or not. Fetal Programming explains that embryonic and fetal adaptive responses in a suboptimal environment generate permanent adverse consequences. Fetal malnutrition as overnutrition increases the risk of developing alterations in fetal body weight and composition, and subsequently obesity, metabolic syndrome, increased adiposity, impaired glucose and / or insulin metabolism, impaired lipid metabolism, liver disorders and altered blood pressure. The genomic imprint is essential for development and defects in it can cause alterations of the parental identity and are transmitted to the following generations. This fetal programming can be explained by epigenetics, defined as the series of inherited alterations of genetic expression through modifications of DNA and central histones without changes in the DNA sequence. These epigenetic modifications alter the structure and condensation of chromatin, affecting the expression of the genotype and phenotype. This article develops the aspects involved in Fetal Programming and the possible mechanisms on it(AU)

Neural origins of basal diencephalon in teleost fishes: Radial versus tangential migration.

Teleost fish possess large lateral diencephalic regions such as the torus lateralis, the preglomerular area, and the diffuse nucleus of the hypothalamic inferior lobe. While their developmental origins traditionally were suggested to lie in diencephalic midline ventricular proliferative zones, more remote midbrain origins were reported recently. This review focuses on the preglomerular region and summarizes the data supporting three existing hypotheses on its developmental origins. The conclusion is that lateral torus, diffuse nucleus of hypothalamic inferior lobe, and preglomerular region are part of the diencephalon, but have a multiregional origin provided by both radially and tangentially migrating cells forming these regions in question.

The influence of microsatellite polymorphisms in sex steroid receptor genes ESR1, ESR2 and AR on sex differences in brain structure.

The androgen receptor (AR), oestrogen receptor alpha (ESR1) and oestrogen receptor beta (ESR2) play essential roles in mediating the effect of sex hormones on sex differences in the brain. Using Voxel-based morphometry (VBM) and gene sizing in two independent samples (discovery n â€‹= â€‹173, replication â€‹= â€‹61), we determine the common and unique influences on brain sex differences in grey (GM) and white matter (WM) volume between repeat lengths (n) of microsatellite polymorphisms AR(CAG)n, ESR1(TA)n and ESR2(CA)n. In the hypothalamus, temporal lobes, anterior cingulate cortex, posterior insula and prefrontal cortex, we find increased GM volume with increasing AR(CAG)n across sexes, decreasing ESR1(TA)n across sexes and decreasing ESR2(CA)n in females. Uniquely, AR(CAG)n was positively associated with dorsolateral prefrontal and orbitofrontal GM volume and the anterior corona radiata, left superior fronto-occipital fasciculus, thalamus and internal capsule WM volume. ESR1(TA)n was negatively associated with the left superior corona radiata, left cingulum and left inferior longitudinal fasciculus WM volume uniquely. ESR2(CA)n was negatively associated with right fusiform and posterior cingulate cortex uniquely. We thus describe the neuroanatomical correlates of three microsatellite polymorphisms of steroid hormone receptors and their relationship to sex differences.

A close neuroanatomical relationship between the enkephalinergic (methionine-enkephalin) and tachykininergic (substance P) systems in the alpaca diencephalon.

INTRODUCTION: In the alpaca diencephalon, the distribution of immunoreactive cell bodies and fibers containing methionine-enkephalin (MET) or substance P (SP) has been studied. MATERIAL AND METHODS: The immunohistochemical study was performed by standard method on the diencephalon of four male alpacas that lived at sea level. RESULTS: Nerve fibers containing MET or SP were widely distributed in the thalamus and hypothalamus. METand SP-immunoreactive fibers showed a similar distribution in the whole diencephalon. Immunoreactive cell bodies containing MET or SP were only observed in the hypothalamus. The distribution of MET-immunoreactive cell bodies was more widespread than that observed for cell bodies containing SP. CONCLUSIONS: A close neuroanatomical relationship between the tachykininergic (SP) and enkephalinergic (MET) systems was observed in the whole diencephalon suggestive of the existence of multiple physiological interactions between both systems.

Short-term captivity drives hypothalamic plasticity and asymmetry in wild-caught northern red bellied dace (Chrosomus eos).

Teleost fish are neuroplastic and are known to alter their brain morphology and behaviour in response to environmental change such as an increase in predation pressure. The hypothalamus plays a key role in regulating behavioural responses to predation risk. In this study, wild-caught northern red bellied dace (Chrosomus eos) developed smaller and less symmetric hypothalami when held in captivity for 14 days; both measures correlated with boldness in a latency to emerge test. This study's results highlight the potential impact of short-term holding conditions on brains and behaviour.

The interrelationship of body mass index with gray matter volume and resting-state functional connectivity of the hypothalamus.

BACKGROUND: The hypothalamus plays an important role in regulating body weight through its interactions with multiple brain circuits involved in distinct aspects of feeding behavior. Yet, how hypothalamic gray matter volume (GMV) and connectivity may be related to individual differences in body weight remains unclear. We tested the hypothesis that the hypothalamus shows enhanced resting-state functional connectivity (rsFC) with regions of the reward, motivation, and motor circuits in positive correlation with body mass index (BMI) and the opposite with those associated with inhibitory control. We further examined the interdependent relationships between hypothalamic GMV, connectivity, and body weight. METHODS: Using seed-based rsFC and voxel-based morphometry analyses, we examined the relationship between the rsFC and GMV of the hypothalamus and BMI in 105 healthy humans. Additionally, we employed mediation analyses to characterize the inter-relationships between hypothalamic connectivity, GMV, and BMI. RESULTS: A whole-brain multiple regression showed that BMI was positively correlated with hypothalamic rsFC with the insula, thalamus, globus pallidus, and cerebellum, and negatively correlated with hypothalamic rsFC with the superior parietal lobule. Thus, higher BMI was associated with enhanced hypothalamic connectivity with regions involved in motivated feeding and reduced connectivity with those in support of cognitive control of food intake. A second whole-brain multiple regression revealed a positive correlation between hypothalamic GMV and the hypothalamus-posterior insula connectivity. Finally, the relationship between hypothalamic GMV and BMI was significantly and bidirectionally mediated by the hypothalamus-posterior insula connectivity. CONCLUSIONS: The current findings suggest that the hypothalamus differentially interacts with the motivation, motor, and control circuits to regulate BMI. We further found evidence for the interdependence of hypothalamic structure, function, and body weight, which provides potential insights into the brain mechanisms of obesity.

Fiber dissection and 3-tesla diffusion tensor tractography of the superior cerebellar peduncle in the human brain: emphasize on the cerebello-hypthalamic fibers.

Experimental studies in various species using tract-tracing techniques showed clear evidence of the presence of cerebello-hypothalamic projections. However, these connections were not clearly described in humans. In the present study we aimed to describe the direct cerebello-hypothalamic connections within the superior cerebellar peduncle (SCP) using fiber dissection techniques on cadaveric brains and diffusion tensor tractography (DTI) in healthy adults. Fiber dissection was performed in a stepwise manner from lateral to medial on 6 cerebral hemispheres. The gray matter was decorticate and fiber tracts were revealed. The SCP was exposed and the fibers were traced distally using wooden spatulas. The MRI examinations were performed in seven cases using 3-tesla 3T unit. The direct cerebello-hyothalamic pathways were exposed using high-spatial-resolution DTI. The present study using both fiber dissection and DTI in adult human showed direct cerebello-hypothalamic fibers within the SCP. The SCP fibers course anterolateral to the cerebral aqueduct reaching the level of the red nucleus of the midbrain. The majority of the fibers crosses over and reached the contralateral diencephalic structures and some of these fibers terminated at the contralateral anterior hypothalamic area. Some of the uncrossed SCP fibers reached the ipsilateral diencephalic structures and terminated at the ipsilateral posterior hypothalamic area. We further reported the close relationship of the SCP with the MCP, lateral lemniscus, red nucleus and substantia nigra. In the DTI evaluations of the SCP we exposed unilateral left cerebello-hypothalamic fibers in five cases and bilateral cerebello-hypothalamic fibers in two cases. The present study demonstrates the direct cerebello-hypothalamic connections within the SCP for the first time using fiber dissection and DTI technique in the human brain. The detailed knowledge of the cerebello-hypothalamic fibers can outline the unexplained deficit that may occur during regional surgery.

Distinctive expression pattern of Peg10 in the mouse brain

Peg10 (paternally expressed 10) is a retrotransposon-derived gene that is highly conserved across mammalian species. Peg10 is involved in cell proliferation and differentiation, and is essential for placenta formation in mice. Although a number of studies have examined Peg10 expression in the placenta, its cellular localization in the brain is still unclear. The function of Peg10 in the brain is also unknown. Here, we examined Peg10 distribution in the mouse brain. In situ hybridization revealed intense expression of the gene in the core region of the accumbens nucleus, lateral division of the bed nucleus of the stria terminalis, medial preoptic nucleus, paraventricular nucleus, arcuate nucleus, dorsomedial hypothalamic nucleus, premammillary nucleus, central amygdaloid nucleus and lateral parabrachial nucleus. Moderate to intense expression of Peg10 was also observed in monoaminergic nuclei such as the substantia nigra, dorsal raphe nucleus and locus coeruleus. These results suggest that Peg10 may play a role in motivational processes, emotional regulation, and autonomic functions in the brain. The findings also suggest that Peg10 may have contributed to the evolution of mammals, not only by participating in placenta formation, but also by regulating parental behavior and hormonal secretions necessary for maternal responsiveness

No disponible

Stereotactic system for accurately targeting deep brain structures in awake head-fixed mice.

Deep brain nuclei, such as the amygdala, nucleus basalis, and locus coeruleus, play a crucial role in cognition and behavior. Nonetheless, acutely recording electrical activity from these structures in head-fixed awake rodents has been very challenging due to the fact that head-fixed preparations are not designed for stereotactic accuracy. We overcome this issue by designing the DeepTarget, a system for stereotactic head fixation and recording, which allows for accurately directing recording electrodes or other probes into any desired location in the brain. We then validated it by performing intracellular recordings from optogenetically tagged amygdalar neurons followed by histological reconstruction, which revealed that it is accurate and precise to within ~100 µm. Moreover, in another group of mice we were able to target both the mammillothalamic tract and subthalamic nucleus. This approach can be adapted to any type of extracellular electrode, fiber optic, or other probe in cases where high accuracy is needed in awake, head-fixed rodents.NEW & NOTEWORTHY Accurate targeting of recording electrodes in awake head-restrained rodents is currently beyond our reach. We developed a device for stereotactic implantation of a custom head bar and a recording system that together allow the accurate and precise targeting of any brain structure, including deep and small nuclei. We demonstrated this by performing histology and intracellular recordings in the amygdala of awake mice. The system enables the targeting of any probe to any location in the awake brain.