Neuroanatomical Relationship Research Articles

Secretoneurin-A inhibits aromatase B (cyp19a1b) expression in female goldfish (Carassius auratus) radial glial cells

In the teleost brain, radial glial cells (RGCs) are the main macroglia and are stem-like progenitors that express key steroidogenic enzymes, including the estrogen-synthesizing enzyme, aromatase B (cyp19a1b). As a result, RGCs are integral to neurogenesis and neurosteroidogenesis, however little is known about the regulatory factors and signaling mechanisms that control these functions. A potential new role of the secretogranin II-derived neuropeptide secretoneurin A (SNa) in the control of goldfish (Carassius auratus) RGC function is the subject of this study. Immunohistochemistry revealed a close neuroanatomical relationship between RGCs and soma of SNa-immunoreactive magnocellular and parvocellular neurons in the preoptic nucleus of female goldfish. Five hours following intracerebroventricular injection of 0.2ng/g SNa cyp19a1b mRNA levels were decreased by 86% (P<0.05) in the hypothalamus and by 88% (P<0.05) in the telencephalon. In vitro, 24 h incubation with 500nM SNa decreased cyp19a1b mRNA by 51% (P<0.05) in cultured RGCs. These data provide evidence that SNa can regulate aromatase expression in goldfish RGCs. By regulating neuroestrogen production in RGCs SNa may therefore be implicated in the control of major estrogen-dependent functions of the preoptic region such as reproductive behavior and osmoregulation.

Neuroanatomical Relationships between Orexin/Hypocretin-Containing Neurons/Nerve Fibers and Nicotine-Induced c-Fos-Activated Cells of the Reward-Addiction Neurocircuitry

Orexin/hypocretin-containing neurons in lateral hypothalamus (LH) are implicated in the neurobiology of nicotine addiction. However, the neuroanatomical relationships between orexin-neurons/nerve fibers and nicotine-activated cells within the reward-addiction neurocircuitry is not known. In the present study in mice, we first used c-Fos immunohistochemistry to identify CNS cells stimulated by an acute single injection of nicotine (NIC, 2 mg/kg, IP). Sequential double-labelling was then performed to identify the location of orexin-containing neurons and nerve fibers with respect to NIC-induced c-Fos activated cells and/or tyrosine hydroxylase (TH) immunoreactive (IR) cells of the mesocorticolimbic reward-addiction pathways. Orexin-IR nerve fibers and terminals were detected at multiple sites of the NIC reward-addiction circuitry in close apposition to, and intermingled with, NIC-induced c-Fos-IR cells of locus coeruleus (LC), ventral tegmental area (VTA), nucleus accumbens (Acb), LH and paraventricular thalamic nucleus (PVT). Double-labelling of orexin with TH showed frequent contact between orexin-IR nerve fibers and noradrenergic cells of LC. However, there was infrequent contact between the orexinergic fibers and the TH-expressing dopaminergic cells of VTA, dorsal raphe nucleus (DR), posterior hypothalamus (DA11), arcuate hypothalamic nucleus (DA12) and periventricular areas (DA14). The close anatomical contact between orexinergic nerve fibers and NIC-activated cells at multiple sites of the reward-addiction pathways suggests that orexinergic projections from LH are likely to be involved in modulating activity of the neurons that are directly impacted by acute administration of nicotine.

The Role of Odor-Evoked Memory in Psychological and Physiological Health

This article discusses the special features of odor-evoked memory and the current state-of-the-art in odor-evoked memory research to show how these unique experiences may be able to influence and benefit psychological and physiological health. A review of the literature leads to the conclusion that odors that evoke positive autobiographical memories have the potential to increase positive emotions, decrease negative mood states, disrupt cravings, and reduce physiological indices of stress, including systemic markers of inflammation. Olfactory perception factors and individual difference characteristics that would need to be considered in therapeutic applications of odor-evoked-memory are also discussed. This article illustrates how through the experimentally validated mechanisms of odor-associative learning and the privileged neuroanatomical relationship that exists between olfaction and the neural substrates of emotion, odors can be harnessed to induce emotional and physiological responses that can improve human health and wellbeing.

State Anxiety Subjective Imbalance and Handicap in Vestibular Schwannoma.

Evidence is emerging for a significant clinical and neuroanatomical relationship between balance and anxiety. Research has suggested a potentially priming effect with anxiety symptoms predicting a worsening of balance function in patients with underlying balance dysfunction. We propose to show that a vestibular stimulus is responsible for an increase in state anxiety, and there is a relationship between increased state anxiety and worsening balance function. (1) To quantify state anxiety following a vestibular stimulus in patients with a chronic vestibular deficit. (2) To determine if state anxiety during a vestibular stimulus would correlate with the severity of chronic balance symptoms and handicap. Two separate cohorts of vestibular schwannoma (VS) patients underwent vestibular tests (electronystagmography, cervical and ocular vestibular evoked myogenic potentials, and caloric responses) and questionnaire assessments [vertigo handicap questionnaire (VHQ), vertigo symptom scale (VSS), and state-trait anxiety inventory (STAIY)]. Fifteen post-resection VS patients, with complete unilateral vestibular deafferentation, were assessed at a minimum of 6 months after surgery in Experiment 1 (Aim 1). Forty-five patients with VS in situ formed the cohort for Experiment 2 (Aim 2). Experiment 1: VS subjects (N = 15) with a complete post-resection unilateral vestibular deafferentation completed a state anxiety questionnaire before caloric assessment and again afterward with the point of maximal vertigo as the reference (Aim 1). Experiment 2: state anxiety measured at the point of maximal vertigo following a caloric assessment was compared between two groups of patients with VS in situ presenting with balance symptoms (Group 1, N = 26) and without balance symptoms (Group 2, N = 11) (Aim 2). The presence of balance symptoms was defined as having a positive score on the VSS-VER. In Experiment 1, a significant difference (p < 0.01) was found when comparing STAIY at baseline and at the peak of the subjective vertiginous response in post-resection patients with a unilateral vestibular deafferentation. In Experiment 2, VS in situ patients with balance symptoms had significantly worse state anxiety at the peak vertiginous response than patients without balance symptoms (p < 0.001), as did patients with a balance-related handicap (p < 0.001). Anxiety symptoms during a vestibular stimulus may contribute to a priming effect that could explain worsening balance function.

An improved method for in vitro morphofunctional analysis of mouse dorsal root ganglia

Sensory neurons in dorsal root ganglia (DRGs) are the first-order neurons along the pathway conveying sensory information from the periphery to the central nervous system. The analysis of the morphological and physiological features of these neurons and their alterations in pathology is the necessary prerequisite to understand pain encoding mechanisms. Here, we describe an in vitro procedure for combined morphofunctional analysis of mouse DRGs. Freshly excised DRGs obtained from adult mice were incubated in collagenase to dissolve the ensheathing connective capsule. The degradation of the connective tissue facilitates both access to the neurons by classical recording glass pipettes and the penetration of primary antibodies for immunohistochemical procedures. The entire DRGs were then imaged using a confocal microscope obtaining a fine 3D representation of their cytoarchitecture without requiring tissue sectioning. Thus, our proposed whole-mount preparation represents a flexible in vitro approach for both functional and phenotypic analysis of DRG neurons by at the same time preserving their neuroanatomical relationships.

Bidirectional Modulation of Numerical Magnitude.

Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct current stimulation (tDCS). This allowed us to demonstrate the first systematic bidirectional modulation of numerical magnitude toward either higher or lower numbers, independently of either eye movements or spatial attention mediated biases. We incorporated both our findings and those from the most widely accepted theoretical framework for numerical cognition to present a novel unifying computational model that describes how numerical magnitude allocation is subject to dynamic interhemispheric competition. That is, numerical allocation is continually updated in a contextual manner based upon relative magnitude, with the right hemisphere responsible for smaller magnitudes and the left hemisphere for larger magnitudes.

Neuroanatomical relationships between FMRFamide-immunoreactive components of the nervus terminalis and the topology of olfactory bulbs in teleost fish.

The nervus terminalis (NT) is the most anterior of the vertebrate cranial nerves. In teleost fish, the NT runs across all olfactory components and shows high morphological variability within this taxon. We compare the anatomical distribution, average number and size of the FMRFamide-immunoreactive (ir) NT cells of fourteen teleost species with different positions of olfactory bulbs (OBs) with respect to the ventral telencephalic area. Based on the topology of the OBs, three different neuroanatomical organizations of the telencephalon can be defined, viz., fish having sessile (Type I), pseudosessile (short stalked; Type II) or stalked (Type III) OBs. Type III topology of OBs appears to be a feature associated with more basal species, whereas Types I and II occur in derived and in basal species. The displacement of the OBs is positively correlated with the peripheral distribution of the FMRFamide-ir NT cells. The number of cells is negatively correlated with the size of the cells. A dependence analysis related to the type of OB topology revealed a positive relationship with the number of cells and with the size of the cells, with Type I and II topologies of OBs showing significantly fewer cells and larger cells than Type III. A dendrogram based on similarities obtained by taking into account all variables under study, i.e., the number and size of the FMRFamide-ir NT cells and the topology of OBs, does not agree with the phylogenetic relationships amongst species, suggesting that divergent or convergent evolutionary phenomena produced the olfactory components studied.

Direct suction decompression and fenestrated clip reconstruction of complex paraclinoid carotid artery aneurysm: operative video and nuances of skull base technique.

Direct microsurgical clipping of complex paraclinoid carotid artery aneuryms remains a formidable technical challenge due to the auneurysm's deep location at the skull base, with adjacent bony anatomy, large size, wide neck, and complex neuroanatomical relationships. In this operative video atlas manuscript, the author demonstrates a step-by-step technique for microsurgical clip reconstruction of a large complex ventral paraclinoid carotid artery aneurysm, using a trapping and direct suction decompression strategy followed by multiple fenestrated clip reconstruction of the internal carotid artery (ICA) via a modified orbitozygomatic approach. The nuances of skull base techniques are illustrated including extradural optic nerve decompression, extradural anterior clinoidectomy, incision of the falciform ligament to untether the optic nerve, and release of the distal durai ring to obtain proximal control. Reconstruction of the ICA and preservation of the anterior choroidal artery were achieved with multiple fenestrated clips. Aneurysm obliteration and patency of flow through the ICA was confirmed on video indocyanine green and catheter angiography. Although novel endovascular strategies continue to evolve, these microsurgical skull base techniques should remain in the surgical armamentarium for treating these complex cranial base vascular lesions. The video can be found here: http://youtu.be/IPS6lslk1ds.

Current Role of Fetal Magnetic Resonance Imaging in Neurologic Anomalies

Magnetic resonance imaging (MRI) is used increasingly to image the fetus when important questions remain unanswered after ultrasonography, which might occur particularly with abnormal amniotic fluid volumes, difficult fetal lie or position, and maternal obesity. Ultrasonography also has limitations due to sound attenuation by bone, such as within the cranium and spine, and therefore MRI has a real advantage in delineating potentially complex neuroanatomical relationships. This article outlines current MRI protocols for evaluation of the fetal neural axis, describes indications for the use of MRI in the fetal brain and spine, and provides examples to illustrate the uses of available fetal sequences.

Tract-tracing study of the extrabulbar olfactory projections in the brain of some teleosts.

The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract-tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer-labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities.

Microsurgical treatment of sagittal sinus, falx meningioma experience (report of 30 cases)

Objective To investigate the effects of surgical method on the falx paraneoplastic parasagittal meningiomas.Methods 30 cases of surgical treatment in sagittal sinus and falx meningioma patients with imaging data,surgical approach,microsurgical resection of the tumor method and efficacy were analyzed.Results 30 patients resected by Simpson standard,Ⅰ grade resection 23 cases,Ⅱ grade resection in 7 cases,no operative mortality.1-5 years of follow-up,2 patients relapsed,all secondary surgical cure.Conclusion To be familiar with microscopic neuroanatomical relationship,using microsurgical resection of the superior sagittal sinus,falx meningioma,tumor removal rate can be increased to reduce the important functional areas of damage,reduce complications and improve quality of life of patients. Key words: Meningioma; Sagittal sinus; Cerebral falx; Micrurgy

Cloning of corticotropin-releasing hormone (CRH) precursor cDNA and immunohistochemical detection of CRH peptide in the brain of the Japanese eel, paying special attention to gonadotropin-releasing hormone

The stress-related corticotropin-releasing hormone (CRH) was first identified by isolation of its cDNA from the brain of the Japanese eel Anguilla japonica. CRH cDNA encodes a signal peptide, a cryptic peptide and CRH (41 amino acids). The sequence homology to mammalian CRH is high. Next, the distribution of CRH-immunoreactive (ir) cell bodies and fibers in the brain and pituitary were examined by immunohistochemistry. CRH-ir cell bodies were detected in several brain regions, e.g., nucleus preopticus pars magnocellularis, nucleus preopticus pars gigantocellularis and formatio reticularis superius. In the brain, CRH-ir fibers were distributed not only in the hypothalamus but also in various regions. Some CRH-ir fibers projected to adrenocorticotropic hormone (ACTH) cells in the rostral pars distalis of the pituitary and also the α-melanocyte-stimulating hormone (α-MSH) cells in the pars intermedia of the pituitary. Finally, the neuroanatomical relationship between the CRH neurons and gonadotropin-releasing hormone (GnRH) neurons was examined by dual-label immunohistochemistry. CRH-ir fibers were found to be in close contact with GnRH-ir cell bodies in the hypothalamus and in the midbrain tegmentum and GnRH-ir fibers were in close contact with CRH-ir cell bodies in the nucleus preopticus pars magnocellularis. These results suggest that CRH has some physiological functions other than the stimulation of ACTH and α-MSH secretion and that reciprocal connections may exist between the CRH neurons and GnRH neurons in the brain of the Japanese eel.

Relationship between olfactory function and social cognition in euthymic bipolar patients

There is a close functional and neuroanatomical relationship between olfactory ability and emotional processing. The present study seeks to explore the association between olfactory ability and social cognition, especially facial emotion perception, in euthymic bipolar patients. Thirty-nine euthymic outpatients meeting DSM-IV-TR criteria for bipolar disorder and 40 healthy volunteers matched on socio-demographic criteria were recruited. Both groups were assessed at one time point with the University of Pennsylvania Smell Identification Test (UPSIT), the Emotion Recognition Test, and The Faux Pas Recognition Test, as well as measures of general cognition and functioning. The bipolar patients showed a significant impairment in olfactory identification (UPSIT) and social cognition measures compared to healthy controls. Analyses revealed significant relationships between olfactory identification and facial emotion recognition, theory of mind, general cognition, and a trend-level relationship with functioning. Controlling for age and cigarettes smoked, relationships remained significant between olfactory function and facial emotion recognition. There is a deficit of olfactory identification in euthymic patients with bipolar disorder that is correlated with a deficit in both verbal and non-verbal measures of social cognition.

ADHD and Sensory Processing Disorders: Placing the Diagnostic Issues in Context

Attention-deficit hyperactivity disorder (ADHD) and sensory processing disorders are behaviorally defined conditions that often co-occur, while both diagnoses have been controversial in part due to the constraints of categorical behavioral diagnosis. However, neuroanatomic studies using neuropsychological tests as “probes” have clearly demonstrated that the various symptoms of ADHD are the result of abnormalities in large-scale brain networks. Sensory processing disorders have not yet been grounded within a neuroanatomical substrate. This article reviews sensory processing disorder as a categorically based diagnosis. It discusses certain possible neuroanatomical relationships between the symptoms of ADHD and sensory processing disorders, and suggests that the symptoms of sensory processing disorders be studied within the dimensional framework of research domain criteria.

Microglia activation along the corticospinal tract following traumatic brain injury in the rat: A neuroanatomical study

Traumatic injury to the brain often manifests itself symptomatically and structurally long after the traumatic event. The cellular basis of this complex response is not completely understood. However, we hypothesized that microglia might contribute to the brain-wide process. To test this hypothesis, we employed optical and electron microscopy to study the microglia in rat brains up to 2months after digitally controlled cortical impact (CCI) to produce traumatic brain injury (TBI). We also used antibodies against ED-1 and Iba-1, respectively, as markers for activated and resting microglia. ED-1 positive microglial cells are observed accompanying the entire corticospinal tract (CST) on the injured side, but not the control, contralateral side of the brain at 2months. In this case, ED-1 and Iba-1 were observed to co-localize uniquely on the injured side of the brain. At earlier times following CCI, ultrastructural studies reveal that microglial cells have very irregular shapes and have many processes that intermingle with degenerating nerve axons of the CST in the hindbrain pyramids. These cells appear to be engulfing degenerating myelinated axons. The debris within the cells is converted to lipofuscin, the antigen for the ED-1 antibody, and remains in the cell cytoplasm throughout the life of the cell. We conclude, as hypothesized, that microglia are critical cellular components. Based on observed close association with myelin degeneration, interdigitating activated microglia may be contributing to damage control. Finally, based on the close neuroanatomical relationship between the lesioned corticospinal tract and the wide distribution of activated microglia, primary signals from CST neurons per se, may be directing microglial responses along the entire damaged rat neuroaxis. The role of persistent activation of microglia has not been determined.

Retention and fracture of a hydrophilic radial artery sheath due to severe spasm

Worldwide, there is increasing interest in transradial intervention, as it appears safer, more cost-effective and is the preferred access route for patients over transfemoral intervention. The favorable neuroanatomical relationships of the radial artery mean that access-site complications are extremely rare. However, radial access-site complications do occur and we report a case of radial artery spasm preventing radial sheath removal, refractory to repeated administration of radial artery vasodilators, intra-arterial papaverine and conscious sedation. Sheath removal was ultimately only possible using an open surgical approach. Radial operators need to be aware of the management of this rare but significant clinical complication.

Connections of the terminal nerve and the olfactory system in two galeomorph sharks: An experimental study using a carbocyanine dye

In elasmobranchs the terminal nerve courses separately from the olfactory nerve. This characteristic makes elasmobranchs excellent models to study the anatomy and function of these two systems. Here we study the neural connections of the terminal nerve and olfactory system in two sharks by experimental tracing methods using carbocyanine dyes. The main projections from the terminal nerve system (consisting of three ganglia in Scyliorhinus canicula) course ipsilaterally to the medial septal nucleus and bilaterally to the ventromedial telencephalic pallial region. Minor terminal nerve projections were also traced ipsilaterally to diencephalic and mesencephalic levels. With regard to the olfactory connections, our results show that in sharks, unlike ray-finned fishes, the primary olfactory projections are mainly restricted to the olfactory bulb. We also performed tracer application to the olfactory bulb in order to analyze the possible central neuroanatomical relationship between the projections of the terminal nerve and the olfactory bulb. In these experiments labeled neurons and fibers were observed from telencephalic to caudal mesencephalic regions. However, we observe almost no overlap between the two systems at central levels. The afferent and the putatively efferent connections of the dogfish olfactory bulb are compared with those previously reported in other elasmobranchs. The significance of the extratelencephalic secondary olfactory projections is also discussed in a comparative context.

Optimizing Patient Positioning and Understanding Radiofrequency Energy in Gynecologic Surgery

Safety in the operating room environment should be a priority for every surgeon. Two areas where safety can often be overlooked and taken for granted are patient positioning and electrosurgical use. Understanding neuroanatomical relationships can help the surgeon optimally position patients and minimize the incidence of postoperative neuropathy while maintaining functional and unobstructed access to the patient and surgical field. Given the widespread use of radiofrequency devices in daily surgical practice, a working knowledge of the principles of electrosurgery is vital to the gynecologic surgeon. Although electrothermal injuries are rare, they can be devastating when unrecognized and poorly understood. Advances in the safety and efficacy of these instruments will continue to aid in decreasing the risks associated with electrosurgery.

Application of neuroanatomical ontologies for neuroimaging data annotation.

The annotation of functional neuroimaging results for data sharing and re-use is particularly challenging, due to the diversity of terminologies of neuroanatomical structures and cortical parcellation schemes. To address this challenge, we extended the Foundational Model of Anatomy Ontology (FMA) to include cytoarchitectural, Brodmann area labels, and a morphological cortical labeling scheme (e.g., the part of Brodmann area 6 in the left precentral gyrus). This representation was also used to augment the neuroanatomical axis of RadLex, the ontology for clinical imaging. The resulting neuroanatomical ontology contains explicit relationships indicating which brain regions are “part of” which other regions, across cytoarchitectural and morphological labeling schemas. We annotated a large functional neuroimaging dataset with terms from the ontology and applied a reasoning engine to analyze this dataset in conjunction with the ontology, and achieved successful inferences from the most specific level (e.g., how many subjects showed activation in a subpart of the middle frontal gyrus) to more general (how many activations were found in areas connected via a known white matter tract?). In summary, we have produced a neuroanatomical ontology that harmonizes several different terminologies of neuroanatomical structures and cortical parcellation schemes. This neuroanatomical ontology is publicly available as a view of FMA at the Bioportal website1. The ontological encoding of anatomic knowledge can be exploited by computer reasoning engines to make inferences about neuroanatomical relationships described in imaging datasets using different terminologies. This approach could ultimately enable knowledge discovery from large, distributed fMRI studies or medical record mining.

Neuroanatomic relationships between the GABAergic and serotonergic systems in the developing human medulla

γ-Amino butyric (GABA) critically influences serotonergic (5-HT) neurons in the raphé and extra-raphé of the medulla oblongata. In this study we hypothesize that there are marked changes in the developmental profile of markers of the human medullary GABAergic system relative to the 5-HT system in early life. We used single- and double-label immunocytochemistry and tissue receptor autoradiography in 15 human medullae from fetal and infant cases ranging from 15 gestational weeks to 10 postnatal months, and compared our findings with an extensive 5-HT-related database in our laboratory. In the raphé obscurus, we identified two subsets of GABAergic neurons using glutamic acid decarboxylase (GAD65/67) immunostaining: one comprised of small, round neurons; the other, medium, spindle-shaped neurons. In three term medullae cases, positive immunofluorescent neurons for both tryptophan hydroxylase and GAD65/67 were counted within the raphé obscurus. This revealed that approximately 6% of the total neurons counted in this nucleus expressed both GAD65/67 and TPOH suggesting co-production of GABA by a subset of 5-HT neurons. The distribution of GABA A binding was ubiquitous across medullary nuclei, with highest binding in the raphé obscurus. GABA A receptor subtypes α1 and α3 were expressed by 5-HT neurons, indicating the site of interaction of GABA with 5-HT neurons. These receptor subtypes and KCC2, a major chloride transporter, were differentially expressed across early development, from midgestation (20 weeks) and thereafter. The developmental profile of GABAergic markers changed dramatically relative to the 5-HT markers. These data provide baseline information for medullary studies of human pediatric disorders, such as sudden infant death syndrome.