The role of the dorsal hippocampus, entorhinal cortex, amygdala and fimbria fornix in spatial discrimination was investigated using temporary inactivation and lesioning methods. Spatial learning was tested in a conditioned cue preference (CCP) paradigm involving three phases of behavioral testing on an 8-arm radial maze. In the first phase (pre-exposure) rats were given unreinforced pre-exposure trials in which they were free to move on two adjacent arms of the maze on three consecutive days. Rats were then alternately confined to the ends of the arms for eight days (training), one arm that contained food (Paired-arm) and one that did not (Unpaired-arm). The rats were then given a choice between the two arms with no food present. Only when given unreinforced pre-exposure trials did rats spend more time in the Paired-arm than in the Unpaired-arm, a CCP. Rats with muscimol induced inactivation of the dorsal hippocampus during unreinforced pre-exposure acquired a CCP for the Paired-arm but were impaired with hippocampal inactivation during training or testing. Inactivation of the entorhinal cortex resulted in impairment in all phases of the paradigm. Inactivation of the dorsal hippocampus in the Unpaired but not Paired-arm only resulted in impairment. The effects of dorsal hippocampus inactivation in either the Paired or Unpaired arms were reversed in rats with combined amygdala lesions\dorsal hippocampus inactivation. Rats with fimbria fornix\entorhinal cortex disconnections during pre-exposure were also impaired. These results reveal that spatial learning may rely on the interactions between the hippocampus, entorhinal cortex, amygdala, and fimbria fornix and that the dogma that the hippocampus mediates all forms of spatial learning requires revision.

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No description available.

Bees and wasps perform learning flights when departing their nest for the first few times or a newly discovered food source. Several studies have described the occurances and structure of these flights in several species, but few have examined how the insects systematically vary the characteristics of their learning flights in various conditions in order to aid the acquisition of visual information. This is best done in a species where individuals and nests can be easily manipulated and tested repeatedly. The aim of this thesis was therefore to investigate learning flights in bumblebees, where we have a good understanding of the structure and variability of flights from previous work and can design controlled experiments. I explored the similarities and differences of learning flights of workers and male bumblebees, observing their departures from the nest or an artificial flower. A second objective was to examine how differences in the learning flights affect the bumblebees’ ability to return the learnt location. The experiments were conducted inside a large greenhouse, under natural light regimes, with two large tables placed far apart, one for simulating the ground from which bees emerged when departing their nest, and the other representing a feeding site with an artificial flower. Female bumblebees performed shorter learning flights when leaving a flower than when leaving their nest, although both locations displayed similar visual scenes. At both locations, the duration and trajectory length of learning flights decreased over successive visits, but the decrease was faster at the flower location than at the nest. Bumblebees fixated both their nest and the flower during their learning flights as well as the landmarks available around the two locations, which suggests that they learned the position of the goal relative to these landmarks. When the nest and the flower were hidden and only three cylinders were shown as landmarks in tests, bees searched as accurately for the nest as for the flower. However, they were more persistent when searching for the nest than for the flower, which was not predicted from the variation of learning flights at the nest and flower locations. Another situation in which bumblebees varied the characteristics of their learning flights, but without an impact on their performance when recalling the learnt information, was after visiting flowers filled with low and high sucrose rewards. The bees performed longer learning flights after drinking at a highly rewarded flower. When departing a poorly rewarded flower, bumblebees did not fixate the flower during their learning flights. Nevertheless, the bees were able to return to both the poorly rewarded flower and the highly rewarded flower equally fast. Given the above findings, it is not evident how different durations or trajectory lengths of bumblebee learning flights might be linked to variations in learning of goal locations. Finally, I show that bumblebees of either sex decide to perform learning flights at locations that are of importance to them. Whilst the female workers always performed learning flights when departing their natal nest, the males did not and simply flew away in a straight line. However, when leaving a flower, the males did perform learning flights with characteristics similar to those of the females’ learning flights. They were also able to return to the flower, showing similar approach trajectories as workers. The thesis discusses these findings in the light of ideas and hypotheses that are linked to differential investment in learning which were observed in the various conditions here. It is also discussed why bumblebees used fixations in different ways when learning about the visual environment surrounding goals that are important to them. Whilst many results are parsimonious with the requirements for learning and active flight control to aid the acquisition of visual information, motivation also seems to play a role in varying the occurances and features of learning flights, such as seen in the bees’ greater persistence to search for their nest than for a flower.

Stress is often an important consideration for animal welfare. A number of factors can contribute to stress in domestic animals, most notably thoseused in food production. We investigated the effects and heritability of stress in domestic chickens (Gallus gallus). Using a spatial learning paradigm, we tested an early social isolation-stressed group and their offspring against unstressed controls, to determine if this cognitive function was negatively affected by stress. In the parental generation, we found that across sessions control birds improved in performance, indicating a learning trend. Stressed birds showed no difference across sessions, indicating a lack of learning. No effects of the parental treatment were found in the offspring of stress and control birds. Social isolation stress was found to affect spatial memory learning, however, we did not find evidence that the parental stress influenced the spatial abilities of the next generation despite changes in other behaviours.

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.

The cockroach, with its large brain and physiological resilience, holds many advantages for the development of behavioral paradigms. The work presented here provides a foundation for, and describes the results of, the implementation of studies of neural correlates of learning and memory on restrained animals.Using the antennal projection response (APR) as an indicator of learning and retention, several learning paradigms have been developed. A visual-olfactory associative and a gustatory-olfactory aversive conditioning paradigm demonstrated a plastic behavior that could be driven in an intact and immobilized cockroach. Conditioning the APR to a visual cue paired with an olfactory cue characterized the role of unilateral and bilateral olfactory input in learning and memory. While unilateral olfactory input is sufficient to learn a visual-olfactory association, bilateral olfactory input is necessary for long-term retention of the association. This comparison identified a critical time period in which memory is consolidated. This time period was subsequently used to analyze gene expression during memory consolidation.The split-brain cockroach preparation was developed to investigate what parts of the brain are necessary and sufficient for learning and retention of a visual-olfactory association; this preparation was also used to examine learning-induced changes in test tissue versus control tissue provided by the same animal. Evidence suggests that half of a brain is sufficient for a visual-olfactory association to be established and sufficient for retention of that association between 12 and 24 hours. However, the entire brain is necessary for long-term memory to be established. Using the split-brain cockroach simultaneously as the control and the test subject, learning-induced alterations in the microglomerular synaptic complexes of the calyces were identified in the trained half, but not in the naïve half.Using the APR, spatial learning and memory was examined. Multiple representations of space were revealed in the brain of the cockroach. Cockroaches represent space in terms of an olfactory gradient map, as well as the visuospatial relationship between objects. When both representations of space can be utilized by the cockroach to localize a cue, the positional visual cue is the one that determines the behavioral response.

Rats learn to navigate to a specific location faster in a familiar environment (Keith and Mcvety 1988). It has been proposed that place learning does not require specific reward signals, but rather, that it occurs automatically. One of the strongest pieces of evidence for the automatic nature of place learning comes from the observation that place and head direction cells reference their receptive fields to prominent landmarks in an environment without needing a reward signal (O’Keefe and Conway 1978; Taube et al. 1990b). It has also been proposed that an allocentric representation of an environment would be bound to the landmarks with the greatest relative stability to guide its orientation (O’Keefe and Nadel 1978). The first two parts of this thesis explore whether place and head direction cells automatically use the most coherent landmarks for orientation. Head direction cells have been shown to orient their preferred firing directs coherently when being exposed to conflicting landmarks in an environment (Yoganarasimha et al. 2006). A model of head direction cells was thus used to explore the necessary mechanisms required to implement an allocentric system that selects landmarks based on their relative stability. We found that the simple addition of Hebbian projections combined with units representing the orientation of landmarks to the head direction cell system is sufficient for the system to exhibit such a capacity. We then recorded both entorhinal head direction cells and CA1 place cells and at the same time subjected the rats to repeated experiences of landmark conflicts. During the conflicts a subset of landmarks always maintained a fixed relative relationship with each other. We found that the visual landmarks retained their ability to control the place and head direction cells even after repeated experience of conflict and that the simultaneously recorded place cells exhibited coherent representations between conflicts. However, the ’stable landmarks’ did not show significantly greater control over the place and head direction cells when comparing to the unstable landmarks. This argues against the hypothesis that the relative stability between landmarks is encoded automatically. We did observe a trend that, with more conflict experience, the ’stable landmarks’ appeared to exert greater control over the cells. The last part of the thesis explores whether goal sensitive cells (Ainge et al. 2007a) discovered from CA1 of hippocampus are developed due to familiarity with the environment or from the demands for rats to perform a win-stay behaviour. We used the same win-stay task as in Ainge et al. and found that there were few or no goal sensitive cells on the first day of training. Subsequent development of goal sensitive activity correlated significantly with the rat’s performance during the learning phase of the task. The correlation provides support to the hypothesis that the development of goal sensitive cells is associated to the learning of the win-stay task though it does not rule out the possibility that these goal sensitive cells are developed due to the accumulated experience on the maze. In summary, this thesis explores what kind of spatial information is encoded by place and head direction cells and finds that relative stability between landmarks without a reward signal is not automatically encoded. On the other hand, when additional information is required to solve a task, CA1 place cells adapt their spatial code to provide the necessary information to guide successful navigation.

Orientador: Elenice Aparecida de Moraes Ferrari / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T19:42:43Z (GMT). No. of bitstreams: 1 Canova_Fernando_D.pdf: 2567655 bytes, checksum: 90b1604e178613eecc7fb38539152db1 (MD5) Previous issue date: 2014 / Resumo: A memória espacial tem importante valor para a sobrevivência do organismo. Está relacionada com sua habilidade em utilizar informações que possibilitam a formação de mapas espaciais de acordo com a relevância das relações entre as pistas ambientais. A memória espacial envolve alterações plásticas no hipocampo de roedores e de aves, dentre essas a indução da transcrição de genes de expressão imediata, tais como o zenk, que regula a expressão de inúmeros outros genes e proteínas. O gene zenk atua na regulação da expressão da proteína Sinapsina. A expressão de sinapsinas também parece estar relacionada com mecanismos sinápticos mediados por receptores GABAB. O presente trabalho teve como objetivo avaliar, em pombos, a aprendizagem, a consolidação e a persistência da memória espacial em situação de escolha alimentar. A plasticidade neural foi investigada pela análise da imunorreatividade para as proteínas Zenk e Sinapsina I no hipocampo. Foram realizados dois experimentos com pombos (Columba livia): No Experimento I foi avaliada a aprendizagem e memória espacial em animais submetidos ao treino de escolha alimentar em 2 ou 7 sessões de treino. Cada sessão teve 6 tentativas experimentais, numa arena circular com 4 comedouros onde apenas um tinha alimento. A resposta de escolha foi definida como orientar-se, aproximar-se e bicar um comedouro. Foi aplicado também o teste de estratégia espacial, que consistiu em 1 sessão, com 3 tentativas experimentais onde na terceira tentativa foram retirados os comedouros e os animais foram colocados na arena circular para análise do tempo de permanência no quadrante onde antes existia o comedouro com alimento. No Experimento II foram avaliados os efeitos do antagonista do receptor GABAB, faclofeno administrado (i.p) imediatamente após as sessões de treino. O teste de persistência da memória espacial foi realizado 7 dias após o treino. A análise imunoistoquímica foi utilizada para avaliação da expressão das proteínas Zenk e Sinapsina I no hipocampo. O número de escolhas corretas aumentou em função do treino, variando entre 50 e 88% na primeira e sétima sessões respectivamente (ANOVA, p < 0,001). O número de núcleos Zenk - positivos e células Sinapsina I - positivas aumentou no hipocampo de pombos treinados durante 7 sessões (ANOVA, p < 0,001). O tratamento com o inibidor do receptor GABAB teve um efeito facilitador nas sessões de treino em comparação com os grupos controles (ANOVA, p < 0,001). Os dados indicam que a experiência em escolha espacial desencadeia a ativação de mecanismos sinápticos que resultam na expressão de Zenk e Sinapsina I no hipocampo de pombos, os quais estão envolvidos na consolidação da memória espacial de escolha alimentar. Os efeitos do tratamento com faclofeno sugerem que o receptor GABAB participa destes mecanismos. Em conjunto os presentes dados demonstraram que o pombo é um modelo experimental importante para a análise de mecanismos de plasticidade neural no hipocampo que são conservados entre espécies de mamíferos e aves / Abstract: The spatial memory has important value for the organism's survival, because it is related with ability to acquire and use space information, enabling the formation of cognitive and spatial maps. The experience with the environment triggers behavioral, cellular and molecular changes in central nervous system that an essential to the formation and consolidation of spatial memory. Therefore, acquisition, consolidation and stability of spatial memory involve plastic changes in the hippocampus of rodents and birds, among these the induction of the expression of early gene transcription such as zenk gene which regulates the expression of numerous other genes and the proteins they control. The gene zenk acts in the formation of new memories and has a role in the regulation of the synapsin protein expression. The expression of synapsins also seems to be related with synaptic mechanisms mediated by the GABAB receptor. This study aimed to evaluate, in pigeons, consolidation and persistence of spatial memory in a situation of food location. The underlying neural plasticity was investigated through the analysis of immunoreactivity for Zenk and Synapsin I proteins in neurons of the hippocampus. Adult, male pigeons (Columba livia) were used in two experiments. Experiment I investigated learning and spatial memory during short (2 sessions) or long duration training (7 sessions). Sessions had 6 experimental trials and were conducted in a arena with 4 feeders. In each trial the bird was released at a different point of the arena, and the time between the release of the bird and the first feeder pecking response (latency of the choice response) was recorded. Testing for spatial strategy was conducted in the arena without any feeder and the time spent in each quadrant was analyzed. Experiment II analyzed the effects of the post-training administration of phaclofen on the consolidation and persistence of spatial memory. Testing of memory persistency occurred 7 days after the 7th training session. Immunohistochemistry of hippocampal tissue was used for the analysis of expression of Zenk and Synapsin I proteins. Number of correct choice increased across training, with values varying between 50 and 88% in the first and 7th session respectively (Anova, p < 0.001). Treatment with GABABantagonist had a facilitatory effect on choice performance which was indicated by lower latency values and higher accuracy values (Anova < 0.001). The values of Zenk positive and Synapsin I positive cells counting were higher in the hippocampus of pigeons that were trained during 7 days and in pigeons treated with phaclofen as compared to their respective controls (Anova p < 0.001). These data indicated that experience with spatial learning of food choice induced expression of Zenk and Synapsin I proteins in the hippocampus of pigeons during the consolidation of spatial memory. Post-training administration of phaclofen suggested a role of GABAB receptor in these experience-dependent synaptic mechanisms. The present results point to the pigeon as interesting animal model for the analysis of neuroplastic mechanisms involved with spatial memory, which are conservative across mammalian and birds species / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

Florida’s Voluntary Pre-Kindergarten program (VPK) aims to ensure that all 4-year-olds are prepared to excel in K-12 mathematics. Early numeracy/spatial skills are predictive of success in K–12 mathematics. No research has examined whether VPK classrooms are equipped with the materials necessary to teach numeracy/spatial skill. The Pre-Kindergarten Numeracy and Spatial Environment Survey was created to examine the frequency of access to and use of numeracy/spatial materials in VPK classrooms. The 69-item survey was completed by the lead educator from a sample of 62 pre-kindergarten classrooms in Miami-Dade County. Regression analysis results suggest the location of the pre-kindergarten center, the sex distribution of the children in the classrooms or the number of years of experience that the educator has as a lead teacher along with the extra training courses undertaken by the teachers does not affect the access to or the use of, numeracy and spatial materials in the classrooms.