Rostral Regions Research Articles

"Clock dial pattern", a radiologic clue to neuro-chikungunya diagnosis: a case series.

Chikungunya is a mosquito-borne disease caused by the chikungunya virus (CHIKV) and can lead to neurological complications in severe cases. This study examined neuroimaging patterns in chikungunya cases during two outbreaks in Brazil to identify specific patterns for diagnosis and treatment of neuro-chikungunya. Eight patients with confirmed chikungunya and neurological involvement were included. Clinical examinations and MRI scans were performed, and findings were analyzed by neuroradiologists. Data on age, sex, neurological symptoms, diagnostic tests, MRI findings, and clinical outcomes were recorded. Patients showed different neuroimaging patterns. Six patients exhibited a "clock dial pattern" with hyperintense dotted lesions in the spinal cord periphery. One patient had thickening and enhancement of anterior nerve roots. Brain MRI revealed multiple hyperintense lesions in the white matter, particularly in the medulla oblongata, in six patients. One patient had a normal brain MRI. The "clock dial pattern" observed in spinal cord MRI may be indicative of chikungunya-related nervous system lesions. Isolated involvement of spinal cord white matter in chikungunya can help differentiate it from other viral infections. Additionally, distinct brainstem involvement in chikungunya-associated encephalitis, particularly in the rostral region, sets it apart from other arboviral infections. Recognizing these neuroimaging patterns can contribute to early diagnosis and appropriate management of neuro-chikungunya.

Central Mechanisms of Thermoregulation and Fever in Mammals.

Thermoregulation is a fundamental homeostatic function in mammals mediated by the central nervous system. The framework of the central circuitry for thermoregulation lies in the hypothalamus and brainstem. The preoptic area (POA) of the hypothalamus integrates cutaneous and central thermosensory information into efferent control signals that regulate excitatory descending pathways through the dorsomedial hypothalamus (DMH) and rostral medullary raphe region (rMR). The cutaneous thermosensory feedforward signals are delivered to the POA by afferent pathways through the lateral parabrachial nucleus, while the central monitoring of body core temperature is primarily mediated by warm-sensitive neurons in the POA for negative feedback regulation. Prostaglandin E2, a pyrogenic mediator produced in response to infection, acts on the POA to trigger fever. Recent studies have revealed that this circuitry also functions for physiological responses to psychological stress and starvation. Master psychological stress signaling from the medial prefrontal cortex to the DMH has been discovered to drive a variety of physiological responses for stress coping, including hyperthermia. During starvation, hunger signaling from the hypothalamus was found to activate medullary reticular neurons, which then suppress thermogenic sympathetic outflows from the rMR for energy saving. This thermoregulatory circuit represents a fundamental mechanism of the central regulation for homeostasis.

Tissue properties and respiratory kinematics of the tongue base and soft palate in the obese OSA minipig.

Obesity is a common finding and a major pathogenetic factor in obstructive sleep apnea (OSA) in adults. To understand the mechanisms behind this, the present study investigated the tissue properties and respiratory kinematics of the tongue base and soft palate in the obese OSA minipig model. In 4 verified obese/OSA and 3 non-obese/non-OSA control minipigs, MRI fat-weighted images, ultrasound elastography (USE), and sleep video-fluoroscopy (SVF) were performed to quantify the fat composition, tissue stiffness, and respiratory kinematics of the tongue base and soft palate during sedated sleep. The results indicated that the fat composition gradually increased from the rostral to caudal tongue base, particularly in the posterior 1/3 of the tongue base, regardless of the presence of obesity and OSA. However, this trend was not seen in the soft palate and pharyngeal wall. The pharyngeal wall presented the highest fat composition as compared with the tongue base and soft palate. Overall, obese OSA minipigs showed stiffer tongue tissue than the controls, particularly in the rostral region of the tongue in obese Yucatan minipigs. The respiratory moving ranges of the soft palate were greater in both dorsal-ventral and rostral-caudal directions and during both respiratory and expiratory phases in OSA obese than control minipigs, and the largest moving ranges were seen in OSA obese Panepinto minipigs. The moving range of the tongue base was significantly smaller. These results suggest more fat infiltration in the caudal region of the tongue base regardless of the presence of obesity and/or OSA. The greater tissue stiffness of the tongue in obese OSA minipigs may result from altered neuromuscular drive.

Sex hormone binding globulin and total testosterone levels are associated with in vivo tau burden differentially between the sexes: findings from the Framingham Study

AbstractBackgroundIn men and women, sex steroid hormones are associated with increased risk of Alzheimer’s disease (AD) dementia. In older men, lower levels of testosterone are associated with higher rates of AD dementia. The relationship between estradiol levels on AD dementia risk in post‐menopausal women, however, is less clear, with studies reporting protective, deleterious and no effects. Finally, higher levels of sex hormone binding globulin (SHBG), a glycoprotein that regulates, and actively influences sex hormones, has been consistently linked with increased risk for AD dementia. Studies have yet to examine mid‐life hormonal levels in association with later‐life in vivo AD biomarkers in cognitively healthy adults.Method175 women and 159 men from the Framingham Study 3rd Generation cohort underwent blood (hormones) collection in 2002‐2005, and 18F‐Flortaucipir (FTP)‐PET and 11C‐PiB‐PET scans in 2016‐2020 (Table1). We examined FTP‐PET signal (referenced to cerebellar grey) in six a priori regions that previously demonstrated sex differences (entorhinal, inferior temporal, rostral middle frontal, inf/sup parietal and lateral occipital). Linear regressions examined sex‐stratified analyses of free/total testosterone, estradiol, and SHBG in each region, adjusting for age, age2, PET camera and plasma‐PET date‐difference (mean = 15(±2)yrs). Separate models examined interactions with a neocortical PiB‐PET composite and APOEε4.ResultIn men, elevated SHBG was associated with lower FTP‐PET in entorhinal (p = 0.007), inferior temporal (p = 0.04) and rostral middle frontal regions (p = 0.02; Table2). Higher total testosterone was marginally associated with lower FTP‐PET signal in the latter region (p = 0.06), but other relationships were apparent. In women, higher total testosterone associated with lower FTP‐PET signal in inferior temporal (p = 0.05) and parietal regions (p = 0.04). Women APOEε4 carriers with higher estradiol showed higher levels of entorhinal FTP‐PET signal (p = 0.03;Table3).ConclusionHigher levels of SHBG are associated with lower risk of AD‐related comorbidities, such as osteoporosis, diabetes, and visceral weight gain. A strong link between higher SHBG levels and higher HDL‐cholesterol may suggest a potential protective cardiovascular pathway for men against higher tau burden later in life. A lack of protective effect of pre‐menopausal estradiol in female APOEε4 carriers supports the notion that the role of estrogen in AD risk is centered around timing of decline.

Transcriptional profiling of Kiss1 neurons from arcuate and rostral periventricular hypothalamic regions in female mice.

The transcriptional profiles of Kiss1 neurons from the arcuate and the rostral periventricular region of the third ventricle of the hypothalamus have been directly compared in diestrous female mice. Differentially expressed genes provide molecular signatures for these two populations of Kiss1 neurons and insights into their physiology. The neuropeptide kisspeptin is produced by Kiss1 neurons and is required for normal mammalian fertility. The two main populations of Kiss1 neurons are located in the arcuate (ARC) and the rostral periventricular area of the third ventricle (RP3V) of the hypothalamus. To define the molecular signature of these Kiss1 populations, transcriptomics profiling was performed using purified Kiss1 neurons from diestrous stage female mice. From a data set of 7026 genes, 332 differentially expressed transcripts were identified between the Kiss1ARC and Kiss1RP3V neurons. These data have uncovered novel transcripts and expanded the receptor expression, co-transmitter and transcription factor profiles of Kiss1 neurons. Validation by quantitative RT-PCR confirmed differential expression of Cartpt, Ddc, Gal, Gda, Npy2r, Penk, Rasp18, Rxfp3, Slc18a2, and Th in Kiss1RP3V neurons and Gpr83, Hctr2, Nhlh2, Nmn, Npr3, Nr4a2, Nr5a2, Olfm2, Tac2 and Tacr3 in Kiss1ARC neurons. Enriched pathways common to both Kiss1 populations included the NF-kB, mTor, endocannabinoid, GPCR, Wnt and oestrogen signalling while some pathways (e.g. cytomegalovirus infection, dopaminergic and serotonergic biosynthesis) were specific to Kiss1RP3V neurons. Our gene expression data set augments the existing data sets describing the transcriptional profiles of Kiss1 neuronal populations.

Sexual dimorphism in skull size and shape of Laticauda colubrina (Serpentes: Elapidae).

Sexual dimorphism in size and shape is widespread among squamate reptiles. Sex differences in snake skull size and shape are often accompanied by intersexual feeding niche separation. However, allometric trajectories underlying these differences remain largely unstudied in several lineages. The sea krait Laticauda colubrina (Serpentes: Elapidae) exhibits very clear sexual dimorphism in body size, with previous studies having reported females to be larger and to have a relatively longer and wider head. The two sexes also differ in feeding habits: males tend to prey in shallow water on muraenid eels, whereas females prey in deeper water on congerid eels. I investigated sexual dimorphism in skull shape and size as well as the pattern of skull growth, to determine whether males and females follow the same ontogenetic trajectories. I studied skull characteristics and body length in 61 male and female sea kraits. The sexes differ in skull shape. Males and females follow distinct allometric trajectories. Structures associated with feeding performance are female-biased, whereas rostral and orbital regions are male-biased. The two sexes differ in allometric trajectories of feeding-related structures (female biased) that correspond to dietary divergence between the sexes. Sea kraits exhibit clear sexual dimorphism in the skull form that may be explained by intersexual differences in the feeding habits as well as reproductive roles. The overall skull growth pattern resembles the typical pattern observed in other tetrapods.

Some morphological structures and histological features of the gills of Binni (Mesopotamichthys sharpeyi)

This study aimed to describe some morphological and histological aspects of the binni fish's gills. Fifteen adult male binni were pulled alive from the Al-Forat River at about (24 - 28) months, immediately after death. The gills of binni were situated on each side of the head beneath a gill cover; the operculum and the gills were made of finger-like long filaments joined to the cartilaginous gill bar. From each filament, numerous fragile lamellae that resemble leaves protrude. These lamellae comprised tiny capillaries covered in plain squamous epithelial cells. The epithelium acts as a barrier between the fish's blood and the surrounding water. The first, second, third, and fourth pairs of gill arches make up the gills supported by the bone skeleton. Each arch carries a row of gill filaments on its convex side and two rows of gill rakers on its concave side. On the rostral concave border, the filaments in the two extremes of the gill were short, but the length of all the filaments was the same. The first-gill arch's lateral rakers were longer than the medial rakers, while the fourth gill arch's medial rakers were longer than the lateral rakers. The rakers, bony comb-like projections, filled the rostral region of the gill arches at the rostral concave interior side. There was interdigitation between the gill rakers of the neighboring gill arches. Each gill arch included the lateral gill rakers pointing dorsolaterally and medial gill rakers pointing dorsomedially. Filaments originate from the gill arches and are maintained by the cartilage on the caudal convex border of the primary lamellae, from which the secondary lamellae emerge. The simple squamous epithelium lined the secondary lamellae. Keywords: Binni, Gill, Morphology, Histology

New information on the mandibular anatomy of Agudotherium gassenae, a Late Triassic non-mammaliaform probainognathian from Brazil.

Agudotherium gassenae is a poorly known non-mammaliaform probainognathian cynodont from the Late Triassic of southern Brazil. It is known only by mandibular remains, and its affinities within Probainognathia are unclear. Furthermore, its phylogenetic affinities were never investigated through computational analyses. In this study, we described new lower jaw remains excavated from the type locality and performed the first phylogenetic investigation of this taxon. The new specimen provides further anatomical information. The rostral region of the lower jaw was poorly preserved in the type series, leading to the interpretation that A. gassenae had three lower incisors. The new specimen demonstrates the presence of four incisors. The phylogenetic analysis positioned A. gassenae as the sister group of Prozostrodontia. This hypothesis differs from that previously presented in the former description of the taxon, in which it was considered a non-mammaliaform prozostrodont by means of character-state comparisons.

Human Spinal Oligodendrogenic Neural Progenitor Cells Enhance Pathophysiological Outcomes and Functional Recovery in a Clinically Relevant Cervical Spinal Cord Injury Rat Model.

Traumatic spinal cord injury (SCI) results in the loss of neurons, oligodendrocytes, and astrocytes. Present interventions for SCI include decompressive surgery, anti-inflammatory therapies, and rehabilitation programs. Nonetheless, these approaches do not offer regenerative solutions to replace the lost cells, fiber tracts, and circuits. Neural stem/progenitor cell (NPC) transplantation is a promising strategy that aims to encourage regeneration. However, NPC differentiation remains inconsistent, thus, contributing to suboptimal functional recovery. As such, we have previously engineered oligodendrogenically biased NPCs (oNPCs) and demonstrated their efficacy in a thoracic model of SCI. Since the majority of patients with SCI experience cervical injuries, our objective in the current study was to generate human induced pluripotent stem cell-derived oNPCs (hiPSC-oNPCs) and to characterize these cells in vitro and in vivo, utilizing a clinically relevant rodent model of cervical SCI. Following transplantation, the oNPCs engrafted, migrated to the rostral and caudal regions of the lesion, and demonstrated preferential differentiation toward oligodendrocytes. Histopathological evaluations revealed that oNPC transplantation facilitated tissue preservation while diminishing astrogliosis. Moreover, oNPC transplantation fostered remyelination of the spared tissue. Functional analyses indicated improved forelimb grip strength, gait, and locomotor function in the oNPC-transplanted rats. Importantly, oNPC transplantation did not exacerbate neuropathic pain or induce tumor formation. In conclusion, these findings underscore the therapeutic potential of oNPCs in promoting functional recovery and histopathological improvements in cervical SCI. This evidence warrants further investigation to optimize and advance this promising cell-based therapeutic approach.

Visual attention to features and space in mice using reverse correlation

Visual attention allows the brain to evoke behaviors based on the most important visual features. Mouse models offer immense potential to gain a circuit-level understanding of this phenomenon, yet how mice distribute attention across features and locations is not well understood. Here, we describe a new approach to address this limitation by training mice to detect weak vertical bars in a background of dynamic noise while spatial cues manipulate their attention. By adapting a reverse-correlation method from human studies, we linked behavioral decisions to stimulus features and locations. We show that mice deployed attention to a small rostral region of the visual field. Within this region, mice attended to multiple features (orientation, spatial frequency, contrast) that indicated the presence of weak vertical bars. This attentional tuning grew with training, multiplicatively scaled behavioral sensitivity, approached that of an ideal observer, and resembled the effects of attention in humans. Taken together, we demonstrate that mice can simultaneously attend to multiple features and locations of a visual stimulus.

Delivery of mutant huntingtin-lowering antisense oligonucleotides to the brain by intranasally administered apolipoprotein A-I nanodisks

Lowering mutant huntingtin (mHTT) in the central nervous system (CNS) using antisense oligonucleotides (ASOs) is a promising approach currently being evaluated in clinical trials for Huntington disease (HD). However, the therapeutic potential of ASOs in HD patients is limited by their inability to cross the blood-brain barrier (BBB). In non-human primates, intrathecal infusion of ASOs results in limited brain distribution, with higher ASO concentrations in superficial regions and lower concentrations in deeper regions, such as the basal ganglia.To address the need for improved delivery of ASOs to the brain, we are evaluating the therapeutic potential of apolipoprotein A-I nanodisks (apoA-I NDs) as novel delivery vehicles for mHTT-lowering ASOs to the CNS after intranasal administration. Here, we have demonstrated the ability of apoA-I nanodisks to bypass the BBB after intranasal delivery in the BACHD model of HD. Following intranasal administration of apoA-I NDs, apoA-I protein levels were elevated along the rostral-caudal brain axis, with highest levels in the most rostral brain regions including the olfactory bulb and frontal cortex. Double-label immunohistochemistry indicates that both the apoA-I and ASO deposit in neurons. Most importantly, a single intranasal dose of apoA-I ASO-NDs significantly reduces mHTT levels in the brain regions most affected in HD, namely the cortex and striatum.This approach represents a novel non-invasive means for improving delivery and brain distribution of oligonucleotide therapies and enhancing likelihood of efficacy. Improved ASO delivery to the brain has widespread application for treatment of many other CNS disorders.

Neuroprotective effects of interleukin 10 in spinal cord injury.

Spinal cord injury (SCI) starts with a mechanical and/or bio-chemical insult, followed by a secondary phase, leading progressively to severe collapse of the nerve tissue. Compared to the peripheral nervous system, injured spinal cord is characterized by weak axonal regeneration, which leaves most patients impaired or paralyzed throughout lifetime. Therefore, confining, alleviating, or reducing the expansion of secondary injuries and promoting functional connections between rostral and caudal regions of lesion are the main goals of SCI therapy. Interleukin 10 (IL-10), as a pivotal anti-inflammatory and immunomodulatory cytokine, exerts a wide spectrum of positive effects in the treatment of SCI. The mechanisms underlying therapeutic effects mainly include anti-oxidative stress, limiting excessive inflammation, anti-apoptosis, antinociceptive effects, etc. Furthermore, IL-10 displays synergistic effects when combined with cell transplantation or neurotrophic factor, enhancing treatment outcomes. This review lists pleiotropic mechanisms underlying IL-10-mediated neuroprotection after SCI, which may offer fresh perspectives for clinical translation.

Modeling Brain Tumors <em>In Vivo</em> Using Electroporation-Based Delivery of Plasmid DNA Representing Patient Mutation Signatures

Tumor models are critical for the preclinical testing of brain tumors in terms of exploring new, more efficacious treatments. With significant interest in immunotherapy, it is even more critical to have a consistent, clinically pertinent, immunocompetent mouse model to examine the tumor and immune cell populations in the brain and their response to treatment. While most preclinical models utilize orthotopic transplantation of established tumor cell lines, the modeling system presented here allows for a "personalized" representation of patient-specific tumor mutations in a gradual, yet effective development from DNA constructs inserted into dividing neural precursor cells (NPCs) in vivo. DNA constructs feature the mosaic analysis with the dual-recombinase-mediated cassette exchange (MADR) method, allowing for single-copy, somatic mutagenesis of driver mutations. Using newborn mouse pups between birth and 3 days old, NPCs are targeted by taking advantage of these dividing cells lining the lateral ventricles. Microinjection of DNA plasmids (e.g., MADR-derived, transposons, CRISPR-directed sgRNA) into the ventricles is followed by electroporation using paddles that surround the rostral region of the head. Upon electrical stimulation, the DNA is taken up into the dividing cells, with the potential of integrating into the genome. The use of this method has successfully been demonstrated in developing both pediatric and adult brain tumors, including the most common malignant brain tumor, glioblastoma. This article discusses and demonstrates the different steps of developing a brain tumor model using this technique, including the procedure of anesthetizing young mouse pups, to microinjection of the plasmid mix, followed by electroporation. With this autochthonous, immunocompetent mouse model, researchers will have the ability to expand preclinical modeling approaches, in efforts to improve and examine efficacious cancer treatment.

Determination of steady-state transcriptome modifications associated with repeated homotypic stress in the rat rostral posterior hypothalamic region.

Chronic stress is epidemiologically correlated with physical and psychiatric disorders. Whereas many animal models of chronic stress induce symptoms of psychopathology, repeated homotypic stressors to moderate intensity stimuli typically reduce stress-related responses with fewer, if any, pathological symptoms. Recent results indicate that the rostral posterior hypothalamic (rPH) region is a significant component of the brain circuitry underlying response reductions (habituation) associated with repeated homotypic stress. To test whether posterior hypothalamic transcriptional regulation associates with the neuroendocrine modifications induced by repeated homotypic stress, RNA-seq was performed in the rPH dissected from adult male rats that experienced either no stress, 1, 3, or 7 stressful loud noise exposures. Plasma samples displayed reliable increases of corticosterone in all stressed groups, with the smallest increase in the group exposed to 7 loud noises, indicating significant habituation compared to the other stressed groups. While few or no differentially expressed genes were detected 24-h after one or three loud noise exposures, relatively large numbers of transcripts were differentially expressed between the group exposed to 7 loud noises when compared to the control or 3-stress groups, respectively, which correlated with the corticosterone response habituation observed. Gene ontology analyses indicated multiple significant functional terms related to neuron differentiation, neural membrane potential, pre- and post-synaptic elements, chemical synaptic transmission, vesicles, axon guidance and projection, glutamatergic and GABAergic neurotransmission. Some of the differentially expressed genes (Myt1l, Zmat4, Dlx6, Csrnp3) encode transcription factors that were independently predicted by transcription factor enrichment analysis to target other differentially regulated genes in this study. A similar experiment employing in situ hybridization histochemical analysis in additional animals validated the direction of change of the 5 transcripts investigated (Camk4, Gabrb2, Gad1, Grin2a and Slc32a) with a high level of temporal and regional specificity for the rPH. In aggregate, the results suggest that distinct patterns of gene regulation are obtained in response to a repeated homotypic stress regimen; they also point to a significant reorganization of the rPH region that may critically contribute to the phenotypic modifications associated with repeated homotypic stress habituation.

Beta‐amyloid regions related to amyloid positivity using a feature selection method

AbstractBackgroundCerebral beta‐amyloid (Aβ) is a hallmark of AD. Few studies have revealed which of the regional Aβ markers are associated with abnormal levels of Aβ status. The aim of the current study was to identify multivariate regional Aβ markers predicting Aβ positivity (Aβ+).MethodSeven hundred and sixty‐five participants from the ADNI‐2 cohort at baseline visit were included in the study. We used regional Aβ uptake as predictors in a predictive model. Flobetapir PET images were classified as Aβ‐positive if the standard uptake value ratio was over 1.1. The least absolute shrinkage and selection operator (LASSO) model with 1,000 bootstrap was implemented to identify regional Aβ traits to predict cortical amyloid burden from participants.ResultOut of 116 predictors, 27 markers in cortical thickness significantly predicted Aβ+ among participants at baseline. After bootstrapping, 2 phenotypes had 95% confidence intervals that did not overlap zero: left precuneus (β = 0.684) and right rostral middle frontal region (β = 0.605).ConclusionThese results demonstrated that several brain regions are related to abnormal levels of cerebral Aβ. These markers suggest robust sign that may capture AD pathology. To this end, this research was supported by the MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center) support program (IITP‐2022‐2017‐0‐01630) supervised by the IITP (Institute for Information & communications Technology Promotion).

Links between psychopathological symptoms and cortical thickness in men with severe alcohol use disorder: A Magnetic Resonance Imaging study.

Anxiety and depression are psychopathological states frequently co-occurring with severe alcohol use disorder (SAUD). These symptoms generally disappear with abstinence but may persist in some patients, increasing the relapse risk. The cerebral cortex thickness of 94 male patients with SAUD was correlated with symptoms of depression and anxiety, both measured at the end (2-3 weeks) of the detoxification treatment. Cortical measures were obtained using surface-based morphometry implemented with Freesurfer. Depressive symptoms were associated with reduced cortical thickness in the superior temporal gyrus of the right hemisphere. Anxiety level was correlated with lower cortical thickness in the rostral middle frontal region, inferior temporal region, and supramarginal, postcentral, superior temporal, and transverse temporal regions of the left hemisphere, as well as with a large cluster in the middle temporal region of the right hemisphere. At the end of the detoxification stage, the intensity of depressive and anxiety symptoms is inversely associated with the cortical thickness of regions involved in emotions-related processes, and the persistence of the symptoms could be explained by these brain deficits.

Altered maturation in brainstem neural conduction in very premature babies with fetal growth restriction.

Using maximum length sequence brainstem auditory evoked response (MLS BAER) to study brainstem neural conduction and maturation in fetal growth restriction (FGR) babies born very prematurely and assess the effect of FGR on brainstem neural maturation. MLS BAER was recorded and analyzed at a mean 40 week postmenstrual age in babies born at 27-32 week gestation without other major perinatal conditions or problems. The data were compared between babies with FGR (n = 30) and age-matched babies without FGR (n = 34) to define any differences. A notable difference in MLS BAER was found in interpeak intervals between the babies with FGR and those without FGR. The FGR babies manifested significantly shortened I-III interval, moderately prolonged III-V interval, and significantly decreased III-V/I-III interval ratio. The slope of the I-III interval-rate function in FGR babies was moderately decreased, relative to that in the babies without FGR. FGR babies born very prematurely are associated with accelerated or precocial neural maturation at caudal brainstem regions, but moderately delayed maturation at rostral brainstem regions. The altered brainstem neural maturation is different from previously reported mildly delayed maturation in FGR babies born less prematurely, and may have important implication for neurodevelopmental outcome. This first MLS BAER study in FGR found that brainstem neural maturation in very premature FGR babies differed from age-matched non-FGR babies. Neural maturation in very premature FGR babies is accelerated or precocial at caudal brainstem regions but moderately delayed at rostral brainstem regions. The altered maturation is different from previously reported mild delay in brainstem neural maturation in FGR babies born less prematurely. FGR exerts a major and differential effect on brainstem neural maturation in babies born very prematurely. This alteration in very premature FGR babies may have important implication for their neurodevelopment.

Scanning electron microscopic characterizations of the tongue of the Nubian goat (Capra aegagrus hircus): A specialized focus on its papillary system adaptation to Egyptian environmental conditions.

The current investigation was focused on describing the gross and scanning electron features of the Nubian goat (Capra aegagrus hircus) tongue, with new insights into its papillary adaptation to the Egyptian environment. The elongated tongue had a rostral free and the caudal fixed. The ventral apical surface is classified into the smaller rostral papillary region on the tip and the larger non-papillary region by the U-line of filiform papillae. Functionally, there are two papillary types: mechanical (filiform, conical and lentiform in addition to the longitudinal row of large conical papilla on the lateral of the body) and gustatory (fungiform and circumvallate). Filiform papillae were densely distributed on the dorsal surface of the apex and body, and on the lateral apical border and lateral surface of the body and root, in addition to the ventral surface of the tip. This filiform papillary system gives a raspy appearance to the dorsal surface. The conical and lentiform papillae were limited to the torus linguae. Circumvallate papillae are surrounded by an annular groove and slightly vallum. The lingual root was devoid of any papillae. Lingual papillary subtypes are filiform papillae (elongated and triangular), conical papillae (elongated and oval) and fungiform papillae (round and ovoid). The investigated Nubian goat may have developed a specialized papillary system due to regional differences in the distribution, structure and subtypes of the system, allowing it to adapt to the dried grasses and leaves of trees and bushes that are available in Upper Egypt's dry, hot climate.

Exceptional features of the embryonic ontogeny of a direct‐developing Robber frog

AbstractIn frogs, the loss of the free‐living tadpole stage implies deep transformations in morphology and development, and the result is a combination of traits exclusive to direct development with the reduction or absence of typically larval features. Two traits stand out in terraranans, a mostly Neotropical clade with ca. 1200 species known or suspected to have direct development: (1) the development of forelimbs, which unlike in tadpoles and in several unrelated direct‐developing lineages, in this clade is described to occur completely exposed during ontogeny, and (2) the reduction of gills and their physiological replacement by highly vascularized tails for gas exchange. In this contribution, we report unusual aspects of the embryonic ontogeny in the Confused Robber frog Oreobates berdemenos, which complicate the interpretation of morphological diversity in Terrarana and in direct‐developing frogs in general. First, forelimbs develop initially entirely concealed by a larval operculum. Second, tail fins develop dorsal and ventral to the tail muscular core but their arrangement changes to lateral during ontogeny. Third, the expansion of the tail fins appears to be a plastic character whose variation likely responds to individual conditions of humidity and/or oxygenation of each egg within the clutch. Finally, we report cells with the morphology of hatching gland cells in the rostral region of embryos at stages about to hatch. If not vestigial, these cells could assist the egg tooth, which is characteristic of terraranans, with chemical softening of the egg capsules during hatching.

Lesions to Caudomedial Nidopallium Impair Individual Vocal Recognition in the Zebra Finch.

Many social animals can recognize other individuals by their vocalizations. This requires a memory system capable of mapping incoming acoustic signals to one of many known individuals. Using the zebra finch, a social songbird that uses songs and distance calls to communicate individual identity (Elie and Theunissen, 2018), we tested the role of two cortical-like brain regions in a vocal recognition task. We found that the rostral region of the Cadomedial Nidopallium (NCM), a secondary auditory region of the avian pallium, was necessary for maintaining auditory memories for conspecific vocalizations in both male and female birds, whereas HVC (used as a proper name), a premotor areas that gates auditory input into the vocal motor and song learning pathways in male birds (Roberts and Mooney, 2013), was not. Both NCM and HVC have previously been implicated for processing the tutor song in the context of song learning (Sakata and Yazaki-Sugiyama, 2020). Our results suggest that NCM might not only store songs as templates for future vocal imitation but also songs and calls for perceptual discrimination of vocalizers in both male and female birds. NCM could therefore operate as a site for auditory memories for vocalizations used in various facets of communication. We also observed that new auditory memories could be acquired without intact HVC or NCM but that for these new memories NCM lesions caused deficits in either memory capacity or auditory discrimination. These results suggest that the high-capacity memory functions of the avian pallial auditory system depend on NCM.SIGNIFICANCE STATEMENT Many aspects of vocal communication require the formation of auditory memories. Voice recognition, for example, requires a memory for vocalizers to identify acoustical features. In both birds and primates, the locus and neural correlates of these high-level memories remain poorly described. Previous work suggests that this memory formation is mediated by high-level sensory areas, not traditional memory areas such as the hippocampus. Using lesion experiments, we show that one secondary auditory brain region in songbirds that had previously been implicated in storing song memories for vocal imitation is also implicated in storing vocal memories for individual recognition. The role of the neural circuits in this region in interpreting the meaning of communication calls should be investigated in the future.