Time and spatial information are always two inseparable entities because if anyone moves in space it also moves in time. However, spatial orientation is much more investigated than interval timing. Time perception is for survival of the individual also very important and it probably works together with spatial perception. Despite this, only a few researches have been focused on this topic and therefore we aimed on evolving a new task which would test use of both of these informations and interaction between them. This new version of AAPA task was tested on Carousel Maze where we usually test only spatial orientation and memory. However, we added also a timing part to our version of the task because we assume that in this task when we turn off the light the rats have to use more interval timing than spatial information. Next part of the task included application of drugs which should compromise timing strategies. We have demonstrated use of different strategies when animals are in darkness and light whereby parts in light depend on spatial orientation and parts in darkness depend more on timing strategies. The drugs didn't disrupt rat's abilities which can be caused by very complex design or by inappropriately chosen doses. Key words time perception, spatial navigation, cognitive function

Spatial navigation is a cognitive skill fundamental to successful interaction with our environment. Normal aging is associated with weaknesses in this skill, with severe deficits in the context of Alzheimer's disease. Identifying mechanisms underlying how the aged brain navigates is important to understanding these age-related weaknesses and potentially strengthening or preserving spatial navigation ability in the aging population. One understudied aspect of spatial navigation is self-motion perception. Important to self-motion perception is optic flow, which is the pattern of visual motion experienced while moving through our environment. Several brain regions are optic flow-sensitive (OF-sensitive), responding more strongly to optic flow than other types of visual motion. The goal of the experiments in this dissertation was to examine the role of visual motion perception and cortical motion area dynamics in spatial navigation in cognitively intact aged adults. Visual path integration tasks were used because they highlight the use of radial and translational optic flow to keep track of one’s position and orientation, respectively. In the first experiment, a positive relationship between radial optic flow sensitivity and visual path integration accuracy that was stronger in aged adults was found. In the second experiment, brain activity was measured using functional magnetic resonance imaging (fMRI) while participants performed visual path integration (VPI) and turn counting (TC) tasks. Stronger activity in the OF-sensitive regions LMT+ and RpVIP during VPI, not TC, was associated with greater VPI accuracy in aged adults. In the third experiment, the functional connectivity between OF-sensitive regions and the rest of the brain during the VPI and TC tasks was measured using fMRI. Stronger average functional connectivity between the OF-sensitive regions LMT+, RMT+, LpVIP, RpVIP, LpV6 and right supramarginal gyrus and posterior cingulate during VPI, not TC, was associated with greater VPI task accuracy in aged adults. The results demonstrate novel relationships between visual path integration accuracy and radial motion perception, the response of OF-sensitive cortical regions during visual navigation, and the interaction strength between OF-sensitive regions and parietal cortex during visual navigation in aged adults. This work expands our knowledge of mechanisms underlying spatial navigation processes in the aged human brain.

Spatial learning in rodents requires normal functioning of hippocampal and cortical structures. Recent data suggest that the cerebellum may also be esential. Neurological mutant mice with dysgenesis of the cerebellum provide useful models to examine the effects of abnormal cerebellar function. Mice with one such mutation, Purkinje cell degeneration (pcd), in which Purkinje cells degenerate between the third and fourth postnatal weeks, were evaluated for performance of spatial navigation learning and visual guidance learning in the Morris maze swim-escape task. Unaffected littermates and C57BL/6J mice served as controls. Separate groups of pcd and control mice were tested at 30, 50 and 110 days of age. At all ages, pcd mice had severe deficits in distal-cue (spatial) navigation, failing to decrease path lengths over training and failing to express appropriate spatial biases on probe trials. On the proximal-cue (visual guidance) task, whenever performance differences between groups did occur, they were limited to the initial trials. The ability of the pcd mice to perform the proximal-cue but not the distal-cue task indicates that the massive spatial navigation deficit was not due simply to motor dysfunction. Histological evaluations confirmed that the pcd mutation resulted in Purkinje cell loss without significant depletion of cells in the hippocampal formation. Teese data provide further evidence that the cerebellum is vital for the expression of behavior directed by spatial cognitive processes.

Two groups of male and female rats were given the same dose of alcohol using an artificial rearing procedure on postnatal days 4-10. One group received the alcohol in a condensed manner each day which caused cyclic blood alcohol concentrations (BACs) with high peaks. A second group received the alcohol in a uniform manner over each day which resulted in moderate, stable BACs. Two control groups consisted of male and female rats artificially reared but not exposed to alcohol and rats reared normally by dams. All rats were raised to 90 days of age and then tested for spatial navigation ability in the Morris water maze, which involved locating a hidden underwater platform using distal extramaze cues. Neither the alcohol treatments nor the artificial rearing had any effects on performance of adult male rats relative to suckle controls in this task. In contrast, the condensed alcohol exposure but not the uniform alcohol exposure resulted in detrimental performance in the Morris water maze by adult female rats. When the ability to locate and escape onto a visible platform was examined, there were no differences between the female groups given condensed alcohol exposure or artificially reared on milk solution alone. Thus, exposure to high BACs during the brain growth spurt has a lasting and selective detrimental effect on spatial navigation learning in adult female but not adult male rats.

<p dir="ltr">Spatial navigation is a complex skill that relies on many aspects of cognition. The following</p><p dir="ltr">studies aimed to clarify the role of working memory in spatial navigation, and particularly, the</p><p dir="ltr">potentially differential contributions of verbal and visuospatial working memory. Study 1</p><p dir="ltr">leveraged individual differences to understand how working memory differs among types of</p><p dir="ltr">navigators and the predictiveness of verbal and visuospatial working memory. Participants</p><p dir="ltr">completed multiple measures of verbal and visuospatial working memory and spatial navigation.</p><p dir="ltr">Study 2 further evaluated the impact of a working memory load on spatial navigation performance.</p><p dir="ltr">Using a dual-task paradigm, the decrement (or not) of performance on spatial navigation can be</p><p dir="ltr">compared between control, verbal, and visuospatial conditions. Study 1 showed that individual</p><p dir="ltr">differences in visuospatial working memory are more predictive than verbal working memory.</p><p dir="ltr">However, Study 2 provides evidence for the necessary role for both verbal and visuospatial</p><p dir="ltr">working memory.</p>

Navigation proficiency - the ability to find and recall new and familiar locations - varies widely among individuals (e.g., Schinazi, Epstein, Nardi, Newcombe, & Shipley, 2013; Weisberg, Schinazi, Newcombe, Shipley, & Epstein, 2014). The cognitive processes that support effective navigation have been theoretically sketched out (e.g., Wolbers & Hegarty, 2010), but how do those processes contribute to aspects of and individual differences in navigation behavior? Using a virtual environment to assess navigation proficiency (Weisberg et al., 2014), we conducted two studies to investigate whether individual differences in navigating meaningfully relate to memory capacity (Study1) and navigation strategy (Study 2). Results from Study 1 suggest that working memory capacity may limit some participants' ability to build accurate cognitive maps. Using a virtual environment paradigm based on the rodent T-maze (Marchette, Bakker, & Shelton, 2011), Study 2 shows that good navigators do not prefer to use a place-based strategy over a response-based strategy, but there was an interaction between strategy selection and goals found. Good navigators who used a place-based strategy found more goals than good navigators who used a response-based strategy; the opposite was true for bad navigators. Emerging from this set of studies is a richer picture of how individual differences in cognitive traits (i.e., working memory capacity), and strategy choice relate to navigation proficiency. / Psychology

All five classes of vertebrates use the geomagnetic field for spatial orientation. The geomagnetic field can be used to derive both 'map' and 'compass' information. There is evidence for two different mechanisms used to sense the magnetic field, the radical pair mechanism (RPM) and the magnetite based mechanism (MBM). C57BL/6 laboratory mice can rely on directional information from the magnetic field to position their nests and to solve a water maze task. The primary objective of this research was to characterize the magnetic compass of C57BL/6 laboratory mice in the plus water maze task. These experiments explored sources of variation in magnetic responses and investigated the underlying magnetic compass orientation mechanism in C57BL/6 mice. The results provide evidence that the mouse magnetic compass is sensitive to low-level radiofrequency fields, consistent with the use of the RPM for magnetic orientation. Surprisingly, the results also suggest that C57BL/6 mice have a polarity sensitive compass, consistent with the use of a MBM for magnetic orientation. These experiments confirm that mice have a specialized magnetic compass sense. Furthermore, despite the controlled environment in which these laboratory experiments were conducted, a variety of factors can increase the variability in the response. Future experiments are needed to further characterize the mouse magnetic compass, as there is a possibility of a hybrid magnetic response where both magnetoreception mechanisms could be used for spatial orientation. / Master of Science

Lors d'une tâche cognitive telle que la navigation spatiale dans un environnement connu, l'individu peut utiliser des stratégies différentes pour atteindre un but. Il peut baser sa navigation sur une représentation mentale de l'espace (globale) ou utiliser une stratégie mettant en jeu des informations égocentriques ou associatives (indices physiques internes ou externes associatifs). Deux grands systèmes cérébraux sont impliqués dans l’apprentissage spatial : la formation hippocampique et les ganglions de la base. Ces deux systèmes utilisent des modalités différentes : l'hippocampe est plus spécifiquement lié à l'apprentissage par rapport à un référentiel externe (apprentissage allocentrique) alors que les ganglions de la base sont plutôt liés à l'apprentissage par rapport à un référentiel interne (apprentissage égocentrique). L’apprentissage parallèle entre les deux systèmes partage à la fois des aspects compétitifs et coopératifs. L’hippocampe étant peu atteint dans les stades précoces de la maladie de Parkinson, ceci fournit l'opportunité de développer des méthodes de rééducation basées sur le renforcement de l'apprentissage allocentrique. Dans cette optique, il faut tout d'abord bien comprendre le fonctionnement de ces mécanismes d'apprentissage dans le cerveau sain. Nous proposons ici un test qui vise à analyser les processus d'apprentissage des deux systèmes, pendant une tâche de navigation dans un labyrinthe. Nous voulons développer une variante de cette tâche qui permet de différencier le rôle respectif de l'hippocampe et des ganglions de la base dans ces processus d'apprentissage. L’objectif de cette étude est d'étudier les différentes modalités d'apprentissage spatial (allocentrique et egocentrique) afin de définir leurs cinétiques d'apprentissage et les interactions entre ces deux systèmes. Ces connaissances seront utilisées par la suite afin de pallier au déficit spécifique d'apprentissage égocentrique dans la maladie de parkinson. Ce projet a pour but de mettre au point une tâche de navigation spatiale permettant de mieux connaitre les modalités des différentes stratégies utilisées lors de la navigation spatiale chez le primate dans un premier temps. Ces données pourront éventuellement servir à l'ajustement d'un protocole pour des sujets humains sains ou souffrant de déficits cognitifs pouvant être compensés par l'adaptation stratégique. / In spatial navigation task, we can use several strategies to reach a goal. We can build a mental representation (global) of the environment, use egocentric (body-based) information or use available cues (internal or external). Two structures known to have roles in spatial information are the hippocampus and the striatum. It is now generally held that allocentric (external reference frame) learning is related to the hippocampus. On the other hand, the striatum is believed to be involved in egocentric representation. There is a parallel processing between those two system which sharing both competitive and cooperative interactions. The hippocampus is less damaged in the early stages of Parkinson disease, this aspect allows the possibility to develop rehabilitation protocols based on the use of allocentered learning when the egocentered one is biased. We have first to better understand how these two systems functionally operate in the normal brain. Here we present a task which permits the study of the spatial learning processes in a maze. Our global aim is to differentiate the respective functions of the hippocampus and basal ganglia in the spatial learning modalities (allocentered or egocentered) and define their kinetics and interactions. The resultant knowledge will may serve to develop cognitive rehabilitation tasks for people with cognitive disorders can be compensated by strategic adaptation.

Finding the right path is a key aspect for successful navigation through the environment, with technologies such as the Global Positioning System (GPS) having improved this. However, human navigators can still be met with incorrect information either from devices or peers. The literature on how individuals then successfully navigate is limited. The current study attempts to fill in some of the gaps, assessing both individual and group differences. The navigation performance of twenty-five young adults was tested using a Virtual Environment (VE) built with Unreal Engine 4. Participants’ self-assessment of spatial ability, trait anxiety, and wayfinding preferences was further assessed through a series of pre- and post-test measures. Using quantitative data analysis, no significant differences in wayfinding strategies when given incorrect information were found and furthermore there was no interaction between trait anxiety and navigational performance. However, participants in general experienced increased difficulty when the incorrect information given was with regards to landmarks. Furthermore, males had decreased accuracy compared to females but only when given incorrect turn information. Even with this lower performance in terms of accuracy, males still rated themselves higher with regards to spatial ability. These results are particularly interesting for human navigation research and might be used to improve GPS-devices or other technology used for navigation (e.g. taking into account gender differences). Further research is needed due to some limitations present in the current study including a limited sample size. / Att hitta rätt väg är grunden för att lyckas hitta rätt väg genom sin omgivning och modern teknologi som GPSen (Global positioning system) har förbättrat detta. Dock så kan en mänsklig navigatör fortfarande presenteras med felaktig information, vare sig det är från teknologiska enheter eller andra individer. Den litteratur som är tillgänglig angående hur folk anpassar sig till detta och ändå försöker finna rätt väg är  begränsad. Denna studie är till för att fylla denna kunskapslucka, både på individuell och på gruppnivå. 25 unga vuxnas navigationsförmågor undersöktes med hjälp av en virtuell miljö skapad i Unreal Engine 4. Deltagarna självutvärderade också sina spatiala förmågor, ångestbenägenhet samt preferenser när det kommer till att utforska och hitta rätt väg. Något som i sin tur komplementerades både före och efter själva experimentet. Kvantitativ dataanalys uppvisade inga märkbara skillnader i navigeringsstrategier när felaktig information hade getts och ingen koppling kunde etableras mellan ångestbenägenhet och prestation. Det fanns dock en trend i upplevda svårigheter när felaktig information angående milstolpar angavs. Män presterade sämre med lägre precision än kvinnor vid missvisande information om svängtillfälle. Men trots detta hade männen en tendens att betygsätta sin spatiala förmåga högre än kvinnor. Dessa resultat är av specifikt intresse för forskning inom navigation och kan användas till att förbättra GPS-enheter samt annan teknologi som utnyttjas för liknande syften (t.ex. för att ta hänsyn till könsskillnaderna). Men mer forskning krävs på grund av vissa begränsningar i undersökningen, inklusive en begränsad provstorlek.

Episodic memory is processed by the extended hippocampal system, and pathology or injury to individual components of this system can result in deficits in spatial learning and memory (Aggleton & Brown, 1999). Extensive research regarding spatial memory has been carried out on the anterior thalamic nuclei, a component of the extended hippocampal system, but the contribution of the laterodorsal thalamic nuclei, an adjacent structure with similar neural connections, is less clear. The purpose of the present study was to compare the effects of selective anterior thalamic nuclei lesions (AT) with selective laterodorsal thalamic nuclei lesions (LD) in a novel land-based spatial reference memory task. This assessed the use of proximal and distal visual cues on the propensity to use allocentric or egocentric navigation strategies to locate a specific place in space, as well as the temporal evolution of these navigation strategies. AT lesion impairments were observed in the acquisition trials in both proximal and distal cue conditions. LD lesion rats were unimpaired in the acquisition trials in both visual cue conditions. Across the probe trials, lesion effects were not observed when tested for general navigation, egocentric or allocentric strategies, and there was no clear improvement in performance over the four weeks of probe trials. However, performance was consistently poorer for all groups when proximal cues facilitated navigation compared to distal cues. Performance differences related to cue proximity may reflect the influence of motion parallax, the perceived displacement rate of visual cues. The absence of lesion effects across probes were thought to be due to the preferential use of cued navigation, which was reliant on a single salient beacon, and the lack of integration between cued and place navigation, which was reliant on the formation of a spatial representation.