Topographic and Structural Anatomy of the Suspensory Ligament of the Penis: Implications for Phalloplasty.

BACKGROUND: The suspensory ligamentous system of the penis supports the penis when erect and plays a key role during coitus. These ligaments, which are prone to injury during coitus, are clinically important in penile reconstruction procedures. OBJECTIVES: The current study investigated the macro- and microanatomy of the suspensory ligamentous system of the penis to determine the origin, course, insertion, dimensions, and tissue composition of these ligaments, knowledge of which is vital for successful penile reconstruction procedures. METHODS: The study utilized a total of 49 cadavers. Gross anatomy dissection, MRI, and histological staining were performed to elucidate the topography, dimensions, and tissue composition of the suspensory ligaments of the penis. RESULTS: Three ligaments were observed to form the suspensory ligamentous system of the penis. The most superficial is the fundiform ligament, which consists of superficial bundles and deep median bundles, with the former arising from the Scarpa's fascia and the latter arising from the linea alba of the anterior abdominal wall; both inserted into the superficial fascia of the penis. The suspensory ligament of the penis arose from the pubic symphysis and inserted into the deep fascia (Buck's fascia) of the penis. The arcuate ligament arose from the body of the pubis and pubic symphysis and inserted into the Buck's fascia. The ligaments were determined to consist of adipose tissue, collagen fibers, elastic fibers and reticular fibers, in varying proportions. CONCLUSIONS: The suspensory ligaments of the penis exhibit a fan-like structure on the penis that allows the forward movement of the penis as a result of engorgement of the erectile bodies while simultaneously offering support.

What is next in African neuroscience?

Working in Africa provides neuroscientists with opportunities that are not available in other continents. Populations in this region exhibit the greatest genetic diversity; they live in ecosystems with diverse flora and fauna; and they face unique stresses to brain health, including child brain health and development, due to high levels of traumatic brain injury and diseases endemic to the region. However, the neuroscience community in Africa has yet to reach its full potential. In this article we report the outcomes from a series of meetings at which the African neuroscience community came together to identify barriers and opportunities, and to discuss ways forward. This exercise resulted in the identification of six domains of distinction in African neuroscience: the diverse DNA of African populations; diverse flora, fauna and ecosystems for comparative research; child brain health and development; the impact of climate change on mental and neurological health; access to clinical populations with important conditions less prevalent in the global North; and resourcefulness in the reuse and adaption of existing technologies and resources to answer new questions. The article also outlines plans to advance the field of neuroscience in Africa in order to unlock the potential of African neuroscientists to address regional and global mental health and neurological problems.

A Need to Protect the Health and Rights of Anatomists Working in Dissection Laboratories.

Anatomy in the context of medical or health science often requires dissection. Anatomical dissection is the purposeful and procedural exploration of the human tissues and organs by physically cutting through defined body planes, regions, and organs to access, define and explore the structures in a manner that facilitates learning. Anatomical dissection is a basic requirement for anatomical and medical education. It is a requirement in certain other fields of health sciences as well. Unfortunately, in many instances, the prosector and dissector in the anatomy laboratories are not considered for the hazards to which they are exposed whether in their health plans or remuneration package. Dissectors, unlike conventional hospital laboratory workers are often considered routine workers or teaching assistants. This is the case, for example, in many African medical institutions. Administrators possibly presume that hazards are only associated with service laboratories in the hospital or teaching hospital departments. It would therefore serve the purpose of advocacy, education, and orientation to highlight the hazards that these individuals who serve as dissectors, prosectors and laboratory staff members are exposed to. This commentary highlights the nature and sources of risks that anatomists who dissect, prosect and work in anatomical laboratories are exposed to. It also highlights how the rights and health of anatomists who dissect can be protected with specific recommendations. Hence, the recommendations speak to policies and practices that are required to serve this purpose. After highlighting the major risks that anatomists who dissect might face, and the major causes of the risks, we wish to propose ways by which these could be addressed based on these key considerations: protect, prevent, and compensate. This is what we have also termed the PPC principle for protecting the health and professional rights of anatomists who dissect and work in anatomical laboratories.

Neurogenesis and Viral Infection.

Neural stem cells (NSCs) are multipotent stem cells that reside in the fetal and adult mammalian brain, which can self-renew and differentiate into neurons and supporting cells. Intrinsic and extrinsic cues, from cells in the local niche and from distant sites, stringently orchestrates the self-renewal and differentiation competence of NSCs. Ample evidence supports the important role of NSCs in neuroplasticity, aging, disease, and repair of the nervous system. Indeed, activation of NSCs or their transplantation into injured areas of the central nervous system can lead to regeneration in animal models. Viral invasion of NSCs can negatively affect neurogenesis and synaptogenesis, with consequent cell death, impairment of cell cycle progression, early differentiation, which cause neural progenitors depletion in the cortical layer of the brain. Herein, we will review the current understanding of Zika virus (ZIKV) infection of the fetal brain and the NSCs, which are the preferential population targeted by ZIKV. Furthermore, the potential neurotropic properties of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may cause direct neurological damage, will be discussed.

Distribution of variations in anatomy of the circle of Willis: results of a cadaveric study of the Malawian population and review of literature.

INTRODUCTION: the circle of Willis is an anatomical structure of clinical importance particularly in the evaluation of neurovascular diseases. Individuals show considerable variations in the anatomical configuration of the circle of Willis. A cross-sectional study was conducted to determine the distribution of morphological variations of the circle of Willis in Malawians and compare with other ethnic groups. METHODS: brains were collected from twenty-four recently deceased black Malawians during autopsy at Queen Elizabeth Central Hospital, a referral teaching hospital in Blantyre, Malawi and fixed in 10% buffered formalin. Digital images of the interpeduncular region (exposing the circle of Willis) were taken with an 18.4 megapixels camera from the base of the brain. Whole-circle and segmental parameters of the circle of Willis were assessed using the Osiris computer programme and classified based on a 22-type classification scheme. RESULTS: the following morphological variations were observed: hypoplasia, aplasia, asymmetry and accessory vessels. Typical circle of Willis was seen in 26% of the cases. Only six of the original twenty-two types were observed. Consistent with most previous studies, types 1, 3, 4, 6, 8 and 9 were common while types 10-22 were rare. Three variants not previously described in the original scheme (unilateral PcoA aplasia, AcoA duplication, and PcoA aplasia with contralateral PcoA hypoplasia) were observed in this study. CONCLUSION: anatomical variations of the circle of Willis in Malawians seem to be distributed in similar frequencies and patterns as in other more-diverse populations. Circle of Willis variants with potential predilection for atherogenesis and aneurysm formation exist in the Malawian population. These should be considered in clinical practice.

Anatomical variation and distribution of the vagus nerve in the esophageal hiatus: a cross-sectional study of post-mortem cases in Uganda.

PURPOSE: Vagus nerve injuries during gastroesophageal surgery may cause significant symptoms due to loss of vagal anti-inflammatory and neuromodulator function. Many previous studies have shown high anatomical variability of the vagus nerve at the esophageal hiatus, but information on its variability in Uganda specifically and Africa in general is scanty. This study provides a reliable and detailed description of the anatomical variation and distribution of the vagus nerve in the esophageal hiatus region of post-mortem cases in Uganda. METHODS: This was an analytical cross-sectional survey of 67 unclaimed post-mortem cases. Data collection used a pretested data collection form. Data were entered into Epi-Info version 6.0 data base then exported into STATA software 13.0 for analysis. RESULTS: The pattern of the anterior vagal trunk structures at the esophageal hiatus was: single trunk [65.7%]; biplexus [20.9%]; triplexus [8.9%] and double-but-not-connected trunks [4.5%]. The pattern of the posterior trunk structures were: single trunk [85.1%]; biplexus 10.4% and triplexus [4.5%]. There was no statistically significant gender difference in the pattern of vagal fibres. There was no major differences in the pattern from comparable British studies. CONCLUSION: The study confirmed high variability in the distribution of the vagus nerve at the esophageal hiatus, unrelated to gender differences. Surgeons must consider and identify variants of vagal innervation when carrying out surgery at the gastroesophageal junction to avoid accidental vagal injuries. Published surgical techniques for preserving vagal function are valid in Uganda.

Coadministration of ARV (Atripla) and Topiramate disrupts quail cardiac neural crest cell migration.

INTRODUCTION: Congenital anomalies such as ventricular septal defects and truncus communis have been reported with the prenatal use of antiretroviral therapy. The mechanism of antiretroviral therapy teratogenicity is unclear and is therefore the focus of this study. Some human immunodeficiency virus patients on antiretrovirals are placed on antiepileptic drugs which are also teratogenic. The interactive effects arising from this therapeutic combination may affect their teratogenic propensity through their effects on neural crest cell migration. METHODS: Appropriately cultured neural crest cells from dissected neural tubes of 32-hr old quail embryos exposed to culture media containing peak plasma levels of Atripla, Topiramate and the combination of both were studied. Distance of migration of neural crest cells was measured using the migration assay and the cells were stained with rhodamine phalloidin to evaluate the cell actin. Also quail neural crest cells were brought into suspension and microinjected into chick hosts to determine the migration of the cells to the interventricular septum. RESULTS: Migration of cultured neural crest cells was extensive in the control cultures, but inhibited in the treated groups. The experimental cultures showed a disarray of actin cytoskeleton contrary to normal distribution of actin filaments in controls. Significantly, few quail neural crest cells migrated to the interventricular septum of chick host embryos compared to the control cultures. The coadministration of topiramate with antiretroviral therapy does not seem to affect the activity of the antiretroviral drug. CONCLUSION: These results indicate that Atripla and Topiramate cause ventricular septal defects by inhibiting the migration of cardiac neural crest cells.

Sleep Deprivation and Neurological Disorders.

Sleep plays an important role in maintaining neuronal circuitry, signalling and helps maintain overall health and wellbeing. Sleep deprivation (SD) disturbs the circadian physiology and exerts a negative impact on brain and behavioural functions. SD impairs the cellular clearance of misfolded neurotoxin proteins like α-synuclein, amyloid-ß, and tau which are involved in major neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. In addition, SD is also shown to affect the glymphatic system, a glial-dependent metabolic waste clearance pathway, causing accumulation of misfolded faulty proteins in synaptic compartments resulting in cognitive decline. Also, SD affects the immunological and redox system resulting in neuroinflammation and oxidative stress. Hence, it is important to understand the molecular and biochemical alterations that are the causative factors leading to these pathophysiological effects on the neuronal system. This review is an attempt in this direction. It provides up-to-date information on the alterations in the key processes, pathways, and proteins that are negatively affected by SD and become reasons for neurological disorders over a prolonged period of time, if left unattended.

Putative adult neurogenesis in palaeognathous birds: The common ostrich (Struthio camelus) and emu (Dromaius novaehollandiae).

In the current study, we examined adult neurogenesis throughout the brain of the common ostrich (Struthio camelus) and emu (Dromaius novaehollandiae) using immunohistochemistry for the endogenous markers PCNA which labels proliferating cells, and DCX, which stains immature and migrating neurons. The distribution of PCNA and DCX labelled cells was widespread throughout the brain of both species. The highest density of cells immunoreactive to both markers was observed in the olfactory bulbs and the telencephalon, especially the subventricular zone of the lateral ventricle. Proliferative hot spots, identified with strong PCNA and DCX immunolabelling, were identified in the dorsal and ventral poles of the rostral aspects of the lateral ventricles. The density of PCNA immunoreactive cells was less in the telencephalon of the emu compared to the common ostrich. Substantial numbers of PCNA immunoreactive cells were observed in the diencephalon and brainstem, but DCX immunoreactivity was weaker in these regions, preferentially staining axons and dendrites over cell bodies, except in the medial regions of the hypothalamus where distinct DCX immunoreactive cells and fibres were observed. PCNA and DCX immunoreactive cells were readily observed in moderate density in the cortical layers of the cerebellum of both species. The distribution of putative proliferating cells and immature neurons in the brain of the common ostrich and the emu is widespread, far more so than in mammals, and compares with the neognathous birds, and suggests that brain plasticity and neuronal turnover is an important aspect of cognitive brain functions in these birds.

Curricular and pedagogical aspects of gross anatomy education for undergraduate physiotherapy students: a scoping review.

OBJECTIVE: The objective of this review was to collate and map gross anatomy curricular and pedagogical approaches for physiotherapy students. INTRODUCTION: Knowledge of anatomy is essential for physiotherapy clinical diagnosis, treatment effectiveness and safe practice. The information on this topic is sparse, and what does exist is diverse. This scoping review describes anatomy educational approaches for physiotherapy students and provides needed insight into this topic. INCLUSION CRITERIA: No limits were applied on the date of the database search or age of participants. Languages were limited to English, French, German and Spanish. Studies had to include information on gross anatomy curricula or pedagogy for physiotherapy students, or information from qualified physiotherapists or those teaching gross anatomy to physiotherapy students. METHODS: Included studies were mainly sourced from EBSCOhost (CINAHL, ERIC and MEDLINE), PubMed and Scopus databases. Perusal of reference lists facilitated further retrievals. Studies published from inception up to 21 July 2019 were included. Studies were identified and screened, and the process was reported in a PRISMA flow diagram. JBI methodology for scoping reviews was followed. Selected studies were charted according to a template created and published in a JBI scoping review protocol. RESULTS: Fifty-four studies satisfied the inclusion criteria. Various studies gave calculable length of intervention in weeks (n=14, 26%), hours (n = 7, 13%) or both (n = 21, 39%). The majority of studies (n = 50, 93%) were cross-sectional studies; three were randomized controlled trials (6%). Mean sample sizes varied from 55.3 ±â€Š30.4 (professional behaviors, ethical and humanistic aspects) to 323.2 ±â€Š219.7 participants (multi-modal and blended learning). Overall, 29 studies (54%) included physiotherapy students or personnel in physiotherapy anatomy programs exclusively in the sample. Other disciplines with physiotherapy students included medical students (n = 12, 22%), and occupational therapy students (n = 10, 19%). The interprofessional education category (n = 8) determined that interdisciplinary teamwork led to increased anatomical learning and awareness of future clinical roles. Computer-assisted learning (n = 9) was effective as a stand-alone or adjunct pedagogy, useful for self-study and helped anatomical knowledge retention. Team-based learning (n = 2), peer teaching (n = 6) and clinical input incorporating case-based learning and horizontal and vertical integration (n = 4) resulted in anatomical knowledge retention and were associated with mastery of anatomical understanding, an increase in examination confidence and higher examination grades. Contradictory learning outcomes resulted from the use of online videos in blended and multi-model learning studies (n = 7). Increased student participation in asynchronous online discussion forums benefitted academic learning outcomes. The category of curriculum, pedagogy and materials (n = 15) identified and compared different survey results pertaining to the curricular aspect of the objectives of this review. One study investigated the flipped classroom concept. The use of anatomy content to encourage professional, ethical and humanistic aspects (n = 3) of physiotherapy students' behavior resulted in positive outcomes. CONCLUSIONS: This scoping review revealed a multi-faceted topic with many types of interventions and outcomes recorded. It identified variations in pedagogies, curricular content and learning approaches integral to the subject and their impact on gross anatomy education for this population. Beneficial behavioral, anatomical learning, knowledge retention and academic outcomes were identified.

Opinions of South African physiotherapists on gross anatomy education for physiotherapy students.

BACKGROUND: Physiotherapists know the depth of gross anatomical knowledge required for safe and effective clinical practice. They can offer insightful opinions on inclusions for and teaching of an anatomy curriculum for physiotherapy students. OBJECTIVES: The aim of this study was to gather opinions of physiotherapists as to what they perceive as necessary anatomy curricular content for undergraduate physiotherapy students and identify pedagogy that should be used. METHOD: A qualitative methodology using a grounded theory approach incorporating semi-structured interviews was utilised in this study. Theoretical sampling was used to identify representative South African physiotherapists. An inductive process, using continuous manual analysis of data by two independent coders, was undertaken. Data were collapsed until themes were identified. Triangulation and other strategies for trustworthiness of data were instituted. RESULTS: Theoretical saturation was reached after five focus groups (n = 32). Demographical information indicated physiotherapists of all age groups and both genders working in diversified clinical areas. Seven themes were identified and incorporated information from 'structure', 'content' and 'pedagogy' for anatomy programmes to the psychological impact of course aspects on a student's psyche. Vertical integration of anatomy into later preclinical years, incorporation of physiotherapists to teach anatomy, a 'physiotherapist personality' and 'anatomy know how' for clinical practice were included. CONCLUSION: Opinions of physiotherapists are important in identifying curricular and teaching considerations that can be incorporated into an anatomy programme designed for physiotherapy students. CLINICAL IMPLICATIONS: Targeted anatomy education for physiotherapy students can aid learning and retention of anatomical knowledge necessary for effective and safe clinical practice.

Cardiotoxicity in African clawed frog (Xenopus laevis) sub-chronically exposed to environmentally relevant atrazine concentrations: Implications for species survival.

The toxic effects of different atrazine concentrations on tadpoles and adult male African clawed frogs (Xenopus laevis) were assessed in a controlled laboratory environment following 90 days' exposure. The aim was to elucidate the danger of atrazine exposure on the cardiac tissue relative to its critical function of rhythmic contractility, fundamental for optimal blood circulation and homeostasis. Tadpoles and adult frogs were exposed to 0 µg/L (control), 0.01 µg L-1, 200 µg L-1 and 500 µg L-1 concentrations of atrazine for 90 days. Mortality was concenration-dependent and significantly increased in juvenile group (77%, 43%, 23% and 0 respectively for 500 µg L-1, 200 µg L-1, 0.01 µg L-1, and control group). While the mean juvenile heart area decreased concentration-dependently, adult frog mean heart area significantly increased in the 200 µg L-1 group only and mean heart weight change was variable across all exposure levels. Light microscopy of hematoxylin and eosin (H&E) and Mallory-Heidenhain rapid one-step staining techniques on cardiac tissue sections of the juvenile and adult frogs revealed shrinkage of cardiac muscle cells into thin wavy myocytes. Additionally, disorganized branching of muscle fibres with reduced striations were observed in 0.01 µg L-1 and 200 µg L-1 but hypertrophied myocytes, thickened intensely staining myofibrils in the 500 µg L-1 group in juvenile and adult frogs. Significant increase in the mean percentage area of connective tissue in all the treated groups (p < 0.036) were also recorded. Immunohistochemistry analysis showed decreased eNOS localization in cardiac tissue in 200 µg L-1 and 500 µg L-1 of both juvenile and adult group, suggestive of decreased cardiac contractility due to atrazine exposure. The results indicate that environmentally relevant atrazine concentrations cause significant mortality in tadpoles while concentrations ≥200 µg L-1 adversely affect cardiac muscle morphology and may induce functional perturbations in cardiac tissue contractility and consequent dysfunction which generally may have an adverse impact on their survival and longevity.

Quantitative analysis of age and life-history stage related changes in DCX expression in the male Japanese quail (Cortunix japonica) telencephalon.

Most avian neurogenesis studies focused on the song control system and little attention has been given to non-song birds such as the Japanese quail. However, the only few neurogenesis studies in quails mainly focused on the sex steroid sensitive areas of the brain such as the medial preoptic and lateral septal nuclei. Despite the important role the quail telencephalon plays in filial imprinting and passive avoidance learning, neurogenesis in this structure has been completely overlooked. The aim of this study was therefore to quantitatively determine how DCX expression in the Japanese quail telencephalon changes with post hatching age (3-12 weeks) and life history stage. In this study, DCX was used as a proxy for neuronal incorporation. Bipolar and multipolar DCX immunoreactive cells were observed in the entire telencephalon except for the entopallium and arcopallium. In addition, DCX expression in all the eight telencephalic areas quantified was strongly negatively correlated with post-hatching age. Furthermore, numbers of bipolar and multipolar DCX immunoreactive cells were higher in the juvenile compared to subadult and adult quails. In conclusion, neuronal incorporation in the quail telencephalon is widespread but it declines with post hatching age. In addition, the most dramatic decline in neuronal incorporation in the telencephalic areas quantified takes place just after the birds have attained sexual maturity.

Age-related changes in Ki-67 and DCX expression in the BALB/ c mouse (Mus Musculus) brain.

Several studies have identified age as one of the strongest regulators of neurogenesis in the mammalian brain. However, previous age-related studies focused mainly on changes in neurogenesis during different stages of adulthood and did not describe changes in neurogenesis through the different life history stages of the animal. The aim of this study was therefore to determine time course changes in neurogenesis in the male BALB/c mouse brain at postnatal ages 1 week to 12 weeks, spanning juvenile, sub adult and adult life history stages. To achieve this, Ki-67 and DCX immunohistochemistry was used to assess changes in cell proliferation and neuronal incorporation respectively. Ki-67 expression was mainly observed in the olfactory bulb, rostral migratory stream, sub ventricular zone of lateral ventricle and the sub granular zone of the dentate gyrus. In addition, fewer Ki-67 positive cells were also observed in the neocortex, cerebellum and tectum. DCX was expressed in similar regions as Ki-67 except for the cerebellum and tectum. Expression of both Ki-67 and DCX sharply decreased with advancing age or life history stages in the sub ventricular zone, rostral migratory stream and sub granular zone of the BALB/c mouse brain. Neurogenesis therefore persists throughout all life history stages in the BALB/c mouse brain although it decreases with age.

Changes to the somatosensory barrel cortex in C57BL/6J mice at early adulthood (56 days post-natal) following prenatal alcohol exposure.

Children with Fetal Alcohol Spectrum Disorder (FASD) have impaired sensory processing skills as a result of neurodevelopmental anomalies. The somatosensory barrel field of rodent brain is a readily accessible model for studying the effects of alcohol exposure. Within the barrel field, the posterior medial barrel subfield (PMBSF) receives sensory inputs from the large vibrissae on the contralateral face. This study reports on the consequence of prenatal exposure to alcohol on the somatosensory cortices of mice later in life. Two control groups, a sucrose and a non-treated control, were also examined. At postnatal day (PND) 56 the cerebral hemisphere of mice from each group were processed for cytochrome oxidase reactivity. In contrast to previous studies, there were no significant differences in the mean areas of: (I) the PMBSF enclosure, (II) the PMBSF barrels, (III) the individual PMBSF barrels and (IV) the septal portion of the PMBSF in the alcohol group compared to the controls. However barrel sizes in rows D and E in the alcohol group were significantly reduced, indicating an alcohol-induced damage on the barrel development and which may reduce the amount of the cortex devoted to processing somatosensory input- a common defect seen in children with FASD.

The brain of the tree pangolin (Manis tricuspis). IV. The hippocampal formation.

Employing a range of standard and immunohistochemical stains we provide a description of the hippocampal formation in the brain of the tree pangolin. For the most part, the architecture, chemical neuroanatomy, and topological relationships of the component parts of the hippocampal formation of the tree pangolin were consistent with that observed in other mammalian species. Within the hippocampus proper fields CA1, 3, and 4 could be identified with certainty, while CA2 was tentatively identified as a small transitional zone between the CA1 and CA3 fields. Within the dentate gyrus evidence for adult hippocampal neurogenesis at a rate comparable to other mammals was observed. The subicular complex and entorhinal cortex also exhibited divisions typically observed in other mammalian species. In contrast to many other mammals, an architecturally and neurochemically distinct CA4 field was observed, supporting Lorente de Nó's proposed CA4 field, at least in some mammalian species. In addition, up to seven laminae were evident in the dentate gyrus. Calretinin immunostaining revealed the three sublamina of the molecular layer, while immunostaining for vesicular glutamate transporter 2 and neurofilament H indicate that the granule cell layer was composed of two sublamina. The similarities and differences observed in the tree pangolin indicate that the hippocampal formation is an anatomically and neurochemically conserved neural unit in mammalian evolution, but minor changes may relate to specific life history features and habits of species.

The brain of the tree pangolin (Manis tricuspis). II. The olfactory system.

This study employed a range of neuroanatomical stains to determine the organization of the main and accessory olfactory systems within the brain of the tree pangolin. The tree pangolin has a typically mammalian olfactory system, but minor variations were observed. The main olfactory system is comprised of the layered main olfactory bulb (MOB), the anterior olfactory nucleus (AON), the rostral olfactory cortex (including the taenia tecta, anterior hippocampal continuation and induseum griseum), the olfactory tubercle (Tu), the lateral olfactory tract (lot) and the olfactory limb of the anterior commissure, the nucleus of the lateral olfactory tract (NLOT), the piriform cortex (PIR) and a typically mammalian rostral migratory stream (RMS). The accessory olfactory system included the layered accessory olfactory bulb (AOB) and the nucleus of the accessory olfactory tract (NAOT). Volumetric analysis of the relative size of the MOB and PIR indicate that the tree pangolin has an olfactory system that occupies a proportion of the brain typical for the majority of mammals. Within the MOB, the glomeruli of the tree pangolin, at 200 µm diameter, are larger than observed in most other mammalian species, and the MOB lacks a distinct internal plexiform layer. In addition, the laminate appearance of the NLOT was not observed in the tree pangolin. The accessory olfactory system appears to lack the posterior compartment of the accessory olfactory bulb. These observations are contextualized in relation to olfactory-mediated behaviors in pangolins.

Brain of the tree pangolin (Manis tricuspis). III. The unusual locus coeruleus complex.

Here, we used a range of immunohistochemical stains, focussing on tyrosine hydroxylase and dopamine-ß-hydroxylase, to show that within the pons of tree pangolins clusters of noradrenergic neurons are present. No noradrenergic neurons were observed in the pontine periventricular gray matter (A6 and A4 groups missing), with all noradrenergic neurons being found within the pontine tegmentum (A7 and A5 groups). The tree pangolin is unique in lacking the locus coeruleus (A6) cell group observed in all vertebrates previously studied; however, noradrenergic axons and terminal networks were found throughout the cerebral cortex. We propose this is achieved through a unique structural reorganization of this system. First, the number of noradrenergic neurons in the compact portion of the subcoeruleus (A7sc) of the tree pangolin is increased, providing a total number of noradrenergic neurons in the pontine tegmentum (A7diffuse, A7sc, A5) that is equivalent to the entire locus coeruleus complex in related species of similar brain mass. Second, the most medially located noradrenergic neurons of the A7sc have dendrites that extend into the ventrolateral periventricular gray matter, in the location where the A6 neurons should have been located, forming a "pseudo A6" region. Third, the topological relationships of this "pseudo A6" region to other neurochemical systems that interact with the A6 neurons, such as the orexinergic, cholinergic, and serotonergic systems, appear to be maintained. Thus, a unique structural plasticity of this region appears to maintain the standard functions of the locus coeruleus complex in this unusual mammalian species.

Changes in neurogenesis with post­hatching age in the male Japanese quail (Cortunix japonica) brain.

Most avian neurogenesis studies have previously focused on the song control system and little attention has been given to non­song birds. The objective of this study was to assess changes in neurogenesis associated with post­hatching age (3­12 weeks) in the Japanese quail brain using proliferating cell nuclear antigen (PCNA) and doublecortin (DCX) immunohistochemistry. PCNA­immunoreactive (ir) cells were observed mainly in the olfactory bulb ventricular zone, telencephalic ventricular zones and cerebellum. Fewer PCNA­ir cells were also observed in the hypothalamus, thalamus and bed nucleus of the stria terminalis. In telencephalic ventricular zones, PCNA­ir cells were concentrated ventrally and dorsally adjacent to the mesopallium and medial striatum, respectively. DCX­ir cells were observed in the olfactory bulb, telencephalon and cerebellum. Furthermore, DCX­ir cells were scattered throughout the pallium except in the entopallium and arcopallium, septal nuclei and striatum. Fewer DCX­ir cells were also observed in the hippocampus and bed nucleus of stria terminalis. The density of PCNA­ir cells and DCX­ir cells in all brain areas declined with post­hatching age. In conclusion, cell proliferation appears to be restricted to the ventricular zones whereas neuronal recruitment is more widespread in the olfactory bulb, telencephalon and cerebellum. Postnatal neuronal incorporation appears to be absent in the diencephalon and mesencephalon.

Putative Adult Neurogenesis in Old World Parrots: The Congo African Grey Parrot (Psittacus erithacus) and Timneh Grey Parrot (Psittacus timneh).

In the current study, we examined for the first time, the potential for adult neurogenesis throughout the brain of the Congo African grey parrot (Psittacus erithacus) and Timneh grey parrot (Psittacus timneh) using immunohistochemistry for the endogenous markers proliferating cell nuclear antigen (PCNA), which labels proliferating cells, and doublecortin (DCX), which stains immature and migrating neurons. A similar distribution of PCNA and DCX immunoreactivity was found throughout the brain of the Congo African grey and Timneh grey parrots, but minor differences were also observed. In both species of parrots, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, subventricular zone of the lateral wall of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and the rhombencephalon. The olfactory bulb and telencephalic subdivisions exhibited a higher density of both PCNA and DCX immunoreactive cells than any other brain region. DCX immunoreactive staining was stronger in the telencephalon than in the subtelencephalic structures. There was evidence of proliferative hot spots in the dorsal and ventral poles of the lateral ventricle in the Congo African grey parrots at rostral levels, whereas only the dorsal accumulation of proliferating cells was observed in the Timneh grey parrot. In most pallial regions the density of PCNA and DCX stained cells increased from rostral to caudal levels with the densest staining in the nidopallium caudolaterale (NCL). The widespread distribution of PCNA and DCX in the brains of both parrot species suggest the importance of adult neurogenesis and neuronal plasticity during learning and adaptation to external environmental variations.