Whirligig beetles are gregarious aquatic insects living on the water surface. They are equipped with two separate pairs of compound eyes, an upper aerial pair and a lower aquatic pair, but little is known about how their brains are organized to serve such an unusual arrangement. In the first study of this dissertation, I describe the neural organization of their primary visual centers (the optic lobes) of the larval and adult whirligig beetle Dineutus sublineatus. I show that the divided compound eyes of adult beetles supply elaborate optic lobes in the brain that are also split into an upper and a lower half, each optic lobe comprising an upper and lower lamina, an upper and lower medulla, and a partly split bilobed lobula. The exception is the fourth neuropil, the lobula plate. Studies of their development show that the lobula plate Anlagen serving the upper and lower eyes develop at different rates and thus different developmental stages. The upper lobula plate develops precociously in the larva and is thought to process information that enables subaquatic ambush hunting. During metamorphosis the upper lobula plate degenerates and is lost as are the larval stemmatal eyes supplying it. The lower lobula plate develops later, during metamorphosis, and is present in the imago where it is supplied by the lower compound retina. By analogy with dipteran lobula plates it is proposed to support subaquatic locomotory balance. In the subsequent study, I describe the neural organization of the whirligig beetle’s mushroom bodies, a pair of prominent brain centers in the forebrain that are best known for their roles in higher olfactory processing and olfactory-based learning and memory. I found that unlike other insects examined so far, the calyces of the whirligig beetle’s mushroom bodies are exclusively supplied by visual neurons from optic lobe neuropils serving the pair of upper aerial compound eyes, thereby showing a complete modality switch from olfaction to vision in this brain center. These findings, along with multiple evidence from hymenopteran insects and cockroaches, suggest that insect mushroom bodies are not merely olfactory-related but may be involved in visual tasks, such as memory of place. In the last study, I describe experiments to demonstrate that a group of D. sublineatus is able to learn their location with respect to visual cues provided from above the water line, and simultaneously establish and maintain their relative positions with each other within the group. These results provide an explanation as to how a collective, such as several hundred whirligig beetles, can maintain cohesion and remember landmarks that "anchor" the collective at a particular location in a pond or stream. Using techniques in comparative neuroanatomy, this dissertation documents visual specializations of an insect brain that has evolved to suit a unique group-living lifestyle on the water surface. In addition, the spatial learning paradigm described in the third study provides an essential assay for future lesion studies to determine if mushroom bodies are indeed required for visually mediated spatial learning and memory.

No description available.

Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August 9, 2009). Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 1997. / Vita. Includes bibliographical references (leaves 161-169).

OBJECTIVES. It has been illustrated in numerous studies that children with Bipolar Disorder (BD) consistently show deficits in declarative memory. There are a number of regions within the brain that have been inferred to correspond to these deficits. Currently, there are a limited number of studies that have analyzed the direct relationship between neuropsychological tests and anatomical brain regions. The purpose of this study was to establish a relationship between structural neuroanatomical measurements and cognitive tasks measurements in Pediatric Bipolar Patients. METHODS. We administered the California Verbal Learning Test-II (CVLT-II) to 46 children and adolescents with BD and compared their scores 35 age-matched healthy controls. A MANCOVA between PBD and Healthy was performed and Long-Delay Free Recall (LDFR) and Long-Delay Cued Recall (LDQR) were significantly different. A multiple linear regression between LDFR and LDQC cognitive variables and anatomical volume and cortical thickness was performed in SPM and FreeSurfer libraries. RESULTS. There was overall significance in CVLT-II Trial 1 (p=0.042), Long Delay Free Recall (LDFR) (p=0.047), and Long Delay Cued Recall (LDQC) scores (0.038), amongst the diagnostic groups (BD-I, BD-II, BD-NOS, Other, Healthy). Within Bipolar subjects, LDFR scores were positive correlated to the gray matter volume of the cingulate gyrus, Brodmann's area 6, parrahippocampal gyrus and the thickness of the lateralorbitofrontal region. LDQC scores were positive correlated to the gray matter volume of the cingulate gyrus, Brodmann's area 7 and middle temporal gyrus. LDQC was also correlated to the volume of the superior frontal, pars triangularis, insula and the thickness of the rostral middle frontal region. CONCLUSION. These results reaffirm previous reports of the cognitive deficits present in children with bipolar disorder. This study also revealed a positive correlation between gray matter density of structures within the limbic system and performance on cognitive variables of the California Verbal Learning Test-II Children's version.

One feature of the brain is that different parts of it respond to different stimuli. This means not all brain regions or neurons within those regions are active at a given moment. This feature of the brain gives it the ability to encode and store a wide range of stimuli that are then used to make predictions about a changing external environment. Activation of non-overlapping neural populations is fundamental to the ability to encode a wide range of stimuli to represent a changing environment. To examine the limits of this idea we used genetic tools to label active cell populations following a neutral stimulus presentation or a learned negative association with the same stimulus. The study examined the degree of similarity between these active populations by comparing key features of the active neurons including gene expression and monosynaptic inputs. Another feature of the brain is its ability to store information. In a neural population recently activated by a salient stimulus, molecular processes occur that result in the formation and maintenance of a memory. Collectively these processes are referred to as plasticity, and act on short and long time scales to strengthen the connections between active neurons and weaken the connections between inactive ones. Plasticity processes are not only necessary for the formation and storage of memories but also for wiring up the nervous system during development. A molecule called ZIP has been shown to erase memories months after formation and specifically affects plasticity on longer time scales. However, the effects of ZIP on the developing brain are not well understood and difficult to study using ZIP’s typical delivery method of injection into the brain. To facilitate a developmental study of ZIP’s effects, we made a genetic tool that can specify where and when ZIP is delivered to the brain. Results of the study indicated that males were particularly vulnerable to ZIP during early development while females were unaffected. Together these results provide insight into the limits of information coding potential at the anatomical level and reveal a fundamental difference in plasticity processes in males and females. / 10000-01-01

Orientador: Luiz Carlos Vulcano / Resumo: O estudo teve como objetivo a determinação das alterações encefálicasrelacionadas ao avanço da idade em gatos domésticos hígidos por meio da ressonânciamagnética. As hipóteses do presente estudo são de que os felinos apresentam dilataçãodo sistema ventricular, atrofia do parênquima encefálico e alterações focais naintensidade do sinal encefálico conforme o avanço da idade. Imagens encefálicas emcortes multiplanares na sequência T1, T2, FLAIR, GRE T2 e T1 pós-contraste foramobtidas de 12 animais adultos (1 a 6 anos), 11 maduros (7 a 11 anos) e 10 geriátricos (12anos ou mais), em um equipamento de ressonância magnética de baixo campo. A alturae a porcentagem do volume do ventrículo lateral direito em relação ao volumeintracraniano, assim como a largura e a porcentagem do volume do terceiro ventrículoem relação ao volume intracraniano, foram significativamente maiores nos animaisgeriátricos em comparação aos adultos. Os indivíduos geriátricos também demonstraramespessura da adesão intertalâmica e porcentagem do volume do parênquima cerebral emrelação ao intracraniano significativamente menores que os encontrados nos adultos. Osresultados do presente estudo confirmaram as hipóteses relacionadas à dilataçãoventricular, especificamente do ventrículo lateral direito e terceiro ventrículo, e à atrofiado parênquima cerebral, assim como da adesão intertalâmica, com o aumento da idadeem gatos. No entanto, os resultados não ratificaram a hipótese referen... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study aimed to determine age related changes in the brain of healthy domesticcats by MRI. The hypotheses of this study are that cats show dilatation of cerebralventricular system, brain atrophy and focal changes in the intensity of the brain signal asadvancing age. Multiplanar images on T1-weighted, T2-weighted, FLAIR, GRE T2 andpost-contrast T1-weighted sequences were obtained from 12 adult (1-6 years), 11 mature(7-11 years) and 10 geriatric cats (12 years or more) in an low-field MRI equipment. Theheight and the percentage of the right lateral ventricle volume in relation to theintracranial volume, as well as the width and the percentage of the third ventricle volumein relation to the intracranial volume, were significantly higher in geriatric compared tothe adult animals. The geriatric cats also demonstrated thickness of the interthalamicadhesion and percentage of cerebral parenchymal volume in relation to intracranialvolume significantly lower than those found in the adult group. The results of this studyconfirm the hypotheses related to ventricular dilatation, specifically of the right lateralventricle and third ventricle, and cerebral atrophy, as well as the interthalamic adhesion,with increasing age in cats. However, the results have not ratified the hypothesis relatedto the cerebellar atrophy and focal changes in the intensity of the brain signal in cats asadvancing age. / Doutor

O objetivo deste estudo é descrever a organização anatômica da glândula pineal do macaco Cebus apella, analisando seus aspectos macroscópicos e microscópicos, vistos sob a óptica da microscopia de luz, microscopia eletrônica de transmissão e microanálise por difração de RX. Para desenvolver este trabalho utilizamos 12 exemplares de macaco Cebus apella, cedidos pelo IBAMA ? MG. Para a análise macroscópica utilizamos 12 animais, os quais foram empregados para estudos relacionados à topografia e sintopia do corpo pineal. Desse grupo, 07 espécimes foram utilizados para a microscopia de luz, 01 espécime para microscopia eletrônica de transmissão e 01 espécime para microscopia eletrônica de varredura, preparados conforme técnicas histológicas de rotina. A glândula pineal do macaco Cebus apella apresentou-se como um pequeno órgão de forma e dimensões variáveis, medindo de 2,5 mm a 4,0 mm de comprimento e de 2,0 mm a 3,5 mm de largura. Está localizada caudalmente ao esplênio do corpo caloso, em correspondência ao recesso pineal, podendo ser classificada como subcalosa e do tipo A, segundo Vollrath (1981). É revestida externamente por uma cápsula de tecido conjuntivo, rica em fibras colágenas, derivada da pia-máter. No parênquima glandular verificam-se três tipos de células: pinealócitos, células da glia e mastócitos. De acordo com as características morfológicas dos núcleos, identificamos pinealócitos do tipo I e pinealócitos do tipo II. Concreções arredondadas e em forma de mórula são vistas no parênquima glandular, nas quais a microanálise por difração de RX demonstrou dois componentes principais: o fósforo e o alumínio / The objective of this study is to describe the anatomical organization of the pineal gland of the Cebus apella monkey, analyzing its macrocospic and microscopical aspects, seen under the optics of the light microscopy, electronic microscopy of transmission and microanalysis by emission of X-Ray. In the development of this study 12 units of Cebus apella monkey, supplied by IBAMA ? MG, were used. For the macrocospic analysis we used 12 animals, which had been used for topography and related to pineal body related studies. From this group, seven specimens were used on the light microscopy, one specimen on electronic microscopy of transmission and one specimen on electronic microscopy of scanning. All the specimens were prepared according to histological techniques of routine. The pineal gland of the Cebus apella monkey presented itself as a small organ of variable forms and lengths, measuring 2,5mm to 4,0mm in length and 2,0mm to 3,5mm in width. It is caudally located to the esplenium of the calosus body, in relation to the pineal recess, being classified as subcalosus and type A according to Vollrath (1981). It is externally covered by a conjunctive tissue capsule, rich in collagen fibers, derived from the piamater. In the glandular parenchyma three types of cells are verified: pinealocytes, cells of the glia and mast cells. According to the morphologic characteristics of the cores, we identify pinealocytes of type I and pinealocytes of type II. Corpora arenaceae round and in morula shape are seen in the glandular parenchyma in which the microanalysis by emission of X-Ray showed two main components: the phosphorus and the aluminum

O conhecimento de diversos aspectos da Neuroanatomia de primatas não humanos - que atualmente é falho, pela falta de trabalhos a respeito - é importante não apenas pela importância intrínseca desse conhecimento como até pelo fato de contribuir para um melhor entendimento da própria evolução do grupo, o que representa um fator relevante para a sua preservação e proteção. O objetivo deste trabalho é efetuar estudos morfológicos da hipófise do macaco Cebus apella a fim de conhecer melhor esta estrutura, e oferecer subsídios para análises comparativas mais amplas. Utilizamos 11 animais sendo 7 deles constantes do acervo de pesquisa da Universidade Federal de Uberlândia e, os outros 4 exemplares, doados pelo IBAMA-MG. A preparação das peças anatômicas foi levada a efeito mediante cuidadosa dissecção dos espécimes, cujos encéfalos foram retirados das caixas cranianas, preservando-se ao máximo todas as suas estruturas. As hipófises, depois de registrada sua macroscopia, foram submetidas aos métodos histológicos de rotina para observações em microscopia de luz e eletrônica de transmissão. Dos resultados obtidos podemos citar que a hipófise, neste animal, é uma glândula intracraniana alojada na sela turcica, fixada à base do cérebro pelo infundíbulo, sendo este muito curto. Ela exibe forma odontóide, exibindo-se aparentemente, como uma massa única, pois macroscopicamente apenas é possível, a identificação de uma divisão discreta em um lobo anterior e outro posterior, além do infundíbulo. As análises histológicas mostram esta glândula dividida em três lobos: anterior (adenohipófise), intermédio e posterior (neurohipófise). À microscopia eletrônica de transmissão foi possível identificar e classificar 4 tipos celulares em relação á adenohipófise: células do tipo I, II, III e IV. O aspecto do núcleo dessas células, exibindo freqüentemente, invaginações profundas de sua membrana, confere à hipófise do macaco Cebus apella, características peculiares, o que nos instiga a realizar novas pesquisas sobre o assunto / The knowledge of many aspects of Neuroanatomy of non-human primates - which is currently poor due to the lack of studies on the subject - is very important not only for the intrinsic significance of the knowledge itself but also because it contributes for a better understanding of the evolution of the group, which represents a relevant factor for its preservation and protection. The objective of this study is to perform morphological researches on the hypophysis of the Cebus apella monkey in order to understand this structure better and to provide basis for wider comparative analyses. Eleven animals were used on this study. Seven of them were properties of the research collection of the Federal University of Uberlândia and the other four were donated by the IBAMA-MG. The preparation of the anatomical parts was carefully done through dissection of the specimens, whose encephalus were removed from their skulls preserving all their structures. The hypophysis, after having their macroscopy registered, were submitted to histological methods of routine for observation in light microscopy and electronic microscopy of transmission. We could conclude from the obtained results that the hypophysis, on this particular animal, is a intracranial gland lodged in the sela turcica fixed to the base of the brain by the infundibulum which is very short. It has in dens shape and it presents itself as a single mass, because, macroscopically, it is only possible the identification of a discrete division in an anterior lobe and another posterior one besides the infundibulum. The histological analyses show this gland divided in three lobes: anterior (adenohypophysis), intermediary and posterior (neurohypophysis). Through the electronic microscopy of transmission it was possible to identify and classify four cellular types related to the adenohypophysis: types I, II, III and IV. The aspect of the cores of these cells, frequently showing deep invaginations of their membranes, confers to hypophysis of the Cebus apella monkey, peculiar characteristics, which instigates us to carry on performing new studies on the subject

Knowledge of human brain evolution primarily relies on the interpretation of palaeoneurological evidence. In the absence of any direct evidence of the fossil neural condition, an endocast (i.e., replica of the internal table of the bony brain case) would constitute a proxy for reconstructing a timeline and mode of cerebral changes in human evolution. The identification of cerebral imprints, and more particularly, of cortical sulci, is indeed critical for assessing the topographic extension and structural organisation of cortical areas. As demonstrated by historical debates in palaeoneurology, however, the description of these crucial landmarks in fossil endocasts is challenging. The recent introduction of high-resolution imaging techniques in (palaeo)neurology offers new opportunities for tracking detailed endocranial neural characteristics. In such context, this study aimed to provide an atlas documenting the variation in the extant human, common chimpanzee and bonobo endocranial sulcal patterns for subsequent use as a comparative platform for the study of the fossil record. The total brain sample population for this study consisted of 60 formalin-fixed human brains from the Department of Anatomy, University of Pretoria, South Africa. Additionally, 58 extant human dry crania from the Pretoria Bone Collection (University of Pretoria, South Africa) which were detailed previously by X-ray microtomography (micro-CT) at the MIXRAD facility, located at the South African Nuclear Corporation (Necsa), Pelindaba, and 22 common chimpanzee and bonobo crania from the Royal Museum for Central Africa (Tervuren, Belgium) that had also been detailed previously using micro-CT at the Centre for X-ray Tomography of the Ghent University (UGCT) were processed and evaluated for inclusion in the study population. Sulci on formalin-fixed brains were documented to create a database of sulcal patterns representing a South African brain sample population. The endocasts were analysed using various software programs and appropriate algorithms, during the post-acquisition process. Finally, a probability map was constructed to document the variation of sulcal imprints on extant human endocasts, based on the identified sulci. This semi-automatic method provides an innovative, non-invasive, observer-independent method to investigate human endocranial structural organisation and a promising perspective for discussing long-standing questions in palaeoneurology. / Dissertation (MSc)--University of Pretoria, 2019. / Anatomy / MSc / Unrestricted