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.

Hippocampal neurogenesis in the C57BL/6J mice at early adulthood following prenatal alcohol exposure.

We examined the effect of chronic prenatal alcohol exposure (PAE) on the process of adult neurogenesis in C57BL/6J mice at early adulthood (PND 56). Pregnant mice, and their in utero litters, were exposed to alcohol, through oral gavage, on gestational days 7-16, with recorded blood alcohol concentrations averaging 184 mg/dL (CA group). Two control groups, sucrose (CAc) and non-treated (NTc) control groups were also examined. The brains of pups at PND 56 from each experimental group were sectioned in a sagittal plane, and stained for Nissl substance with cresyl violet, and immunostained for Ki-67 which labels proliferative cells and doublecortin (DCX) for immature neurons. Morphologically, the neurogenic pattern was identical in all three groups studied. Populations of Ki-67 immunopositive cells in the dentate gyrus were not statistically significantly different between the experimental groups and there were no differences between the sexes. Thus, the PAE in this study does not appear to have a strong effect on the proliferative process in the adult hippocampus. In contrast, the numbers of immature neurons, labeled with DCX, was statistically significantly lower in the prenatal alcohol exposed mice compared with the two control groups. Alcohol significantly lowered the number of DCX hippocampal cells in the male mice, but not in the female mice. This indicates that the PAE appears to lower the rate of conversion of proliferative cells to immature neurons and this effect of alcohol is sexually dimorphic. This lowered number of immature neurons in the hippocampus appears to mirror hippocampal dysfunctions observed in FASD children.

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.

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.

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.

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.

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.

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.

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.

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.

Distribution and morphology of putative catecholaminergic and serotonergic neurons in the brain of the greater canerat, Thryonomys swinderianus.

The distribution, morphology and nuclear subdivisions of the putative catecholaminergic and serotonergic systems within the brain of the greater canerat (sometimes spelt cane rat) were identified following immunohistochemistry for tyrosine hydroxylase and serotonin. The aim of the present study was to investigate possible differences in the complement of nuclear subdivisions of these systems when comparing those of the greater canerat with reports of these systems in other rodents. The greater canerat was chosen for investigation as it is a large rodent (around 2.7kg body mass) and has an average brain mass of 13.75g, more than five times larger than that of the laboratory rat. The greater canerats used in the present study were caught from the wild, which is again another contrast to the laboratory rat. While these differences, especially that of size, may lead to the prediction of significant differences in the nuclear complement of these systems, we found that all nuclei identified in both systems in the laboratory rat and other rodents in several earlier studies had direct homologs in the brain of the greater canerat. Moreover, there were no additional nuclei in the brain of the greater canerat that are not found in the laboratory rat or other rodents. It is noted that the locus coeruleus of the laboratory rat differs in appearance to that reported for several other rodent species. The greater canerat is phylogenetically distant from the laboratory rat, but still a member of the order Rodentia. Thus, changes in the nuclear organization of these systems appears to demonstrate a form of constraint related to the phylogenetic level of the order.

Nuclear organization and morphology of serotonergic neurons in the brain of the Nile crocodile, Crocodylus niloticus.

The present study describes the location and nuclear organization of the serotonergic system in a representative of the order Crocodylia, the Nile crocodile (Crocodylus niloticus). We found evidence for serotonergic neurons in three regions of the brain, including the diencephalon, rostral and caudal brainstem, as previously reported in several other species of reptile. Within the diencephalon we found neurons in the periventricular organ of the hypothalamus, but not in the infundibular recess as noted in some other reptilian species. In addition we found serotonergic neurons in the pretectal nucleus, this being the first description of these neurons in any species. Within the rostral brainstem we found medial and lateral divisions of the superior raphe nucleus and a widely dispersed group of neurons in the tegmentum, the superior reticular nucleus. In the caudal brainstem we observed the inferior raphe nucleus and the inferior reticular nucleus. While much of the serotonergic system of the Nile crocodile is similar to that seen in other reptiles the entire suite of features appears to distinguish the crocodile studied from the members of the Squamate (lizards and snakes) and Testudine (turtles, tortoises and terrapins) reptiles previously studied. The observations are suggestive of order-specific patterns of nuclear organization of this system in the reptiles, reflecting potential evolutionary constraints in the mutability of the nuclear organization as seen for similar systems in mammals.

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.

Gross anatomy education for South African undergraduate physiotherapy students.

Eight faculties in South Africa offer undergraduate physiotherapy training with gross anatomy included as a basis for clinical practice. Little information exists about anatomy education for this student body. A 42-question peer-reviewed survey was distributed to physiotherapy gross anatomy course coordinators in all the eight faculties. Seven coordinators from six (75%) of the universities responded. Two respondents' data from the same university were pooled. Collected data show that staff qualifications and experience varied widely and high to average staff to student ratios exist between faculties. Direct anatomy teaching duration was 12.3 (SD ±5.2) weeks per semester. Total number of weeks in courses per faculty was 27.6 (SD ±5.7) varying widely between institutions. Calculable direct contact anatomy hours ranged between 100 and 308 with a mean of 207.6 (SD ±78.1). Direct contact hours in lectures averaged 3.9 (SD ±1.6) per week and the average direct contact hours in practical sessions were 3.5 (SD ±1.8) per week. Dissection, prosection, plastinated models, surface anatomy, and e-learning were available across faculties. Ancillary modalities such as vertical integration and inter-professional learning were in use. All faculties had multiple-choice questions, spot tests, and short examination questions. Half had viva-voce examinations and one had additional long questions assessment. Students evaluated teaching performance in five faculties. Four faculties were reviewing anatomy programs to consider implementing changes to anatomy curriculum or pedagogy. The findings highlighted disparity between programs and also identified the need for specific guidelines to develop a unified South African gross anatomy course for physiotherapy students.

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.

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.

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.

The Distribution of Ki-67 and Doublecortin-Immunopositive Cells in the Brains of Three Strepsirrhine Primates: Galago demidoff, Perodicticus potto, and Lemur catta.

This study investigated the pattern of adult neurogenesis throughout the brains of three prosimian primate species using immunohistochemical techniques for endogenous markers of this neural process. Two species, Galago demidoff and Perodicticus potto, were obtained from wild populations in the primary rainforest of central Africa, while one species, Lemur catta, was captive-bred. Two brains from each species, perfusion-fixed with 4% paraformaldehyde, were sectioned (50 µm section thickness) in sagittal and coronal planes. Using Ki-67 and doublecortin (DCX) antibodies, proliferating cells and immature neurons were identified in the two canonical neurogenic sites of mammals, the subventricular zone of the lateral ventricle (SVZ) giving rise to the rostral migratory stream (RMS), and the subgranular zone of the dentate gyrus of the hippocampus. In addition a temporal migratory stream (TMS), emerging from the temporal horn of the lateral ventricle to supply the piriform cortex and adjacent brain regions with new neurons, was also evident in the three prosimian species. While no Ki-67-immunoreactive cells were observed in the cerebellum, DCX-immunopositive cells were observed in the cerebellar cortex of all three species. These findings are discussed in a phylogenetic context.