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Astronauts often face orientation challenges while on orbit, which can lead to operator errors in demanding spatial tasks. In this study, we investigated the impact of long-duration spaceflight on the neural processes supporting astronauts' spatial orientation skills. Using functional magnetic resonance imaging (fMRI), we collected data from 16 astronauts six months before and two weeks after their International Space Station (ISS) missions while performing a spatial orientation task that requires generating a mental representation of one's surroundings. During this task, astronauts exhibited a general reduction in neural activity evoked from spatial-processing brain regions after spaceflight. The neural activity evoked in the precuneus was most saliently reduced following spaceflight, along with less powerful effects observed in the angular gyrus and retrosplenial regions of the brain. Importantly, the reduction in precuneus activity we identified was not accounted for by changes in behavioral performance or changes in grey matter concentration. These findings overall show less engagement of explicitly spatial neurological processes at postflight, suggesting astronauts make use of complementary strategies to perform some spatial tasks as an adaptation to spaceflight. These preliminary findings highlight the need for developing countermeasures or procedures that minimize the detrimental effects of spaceflight on spatial cognition, especially in light of planned long-distance future missions. [ABSTRACT FROM AUTHOR]

Mental simulation is a hallmark feature of human cognition, allowing features from memories to be flexibly used during prospection. While past studies demonstrate the preservation of real-world features such as size and distance during mental simulation, their temporal dynamics remains unknown. Here, we compare mental simulations to navigation of routes in a large-scale spatial environment to test the hypothesis that such simulations are temporally compressed in an adaptive manner. Our results show that simulations occurred at 2.39× the speed it took to navigate a route, increasing in compression (3.57×) for slower movement speeds. Participant self-reports of vividness and spatial coherence of simulations also correlated strongly with simulation duration, providing an important link between subjective experiences of simulated events and how spatial representations are combined during prospection. These findings suggest that simulation of spatial events involve adaptive temporal mechanisms, mediated partly by the fidelity of memories used to generate the simulation. [ABSTRACT FROM AUTHOR]

Schizophrenia is associated with deficits in face perception and emotion recognition. Despite consistent behavioural results, the neural mechanisms underlying these cognitive abilities have been difficult to isolate, in part due to differences in neuroimaging methods used between studies for identifying regions in the face processing system. Given this problem, we aimed to validate a recently developed fMRI-based dynamic functional localizer task for use in studies of psychiatric populations and specifically schizophrenia. Previously, this functional localizer successfully identified each of the core face processing regions (i.e. fusiform face area, occipital face area, superior temporal sulcus), and regions within an extended system (e.g. amygdala) in healthy individuals. In this study, we tested the functional localizer success rate in 27 schizophrenia patients and in 24 community controls. Overall, the core face processing regions were localized equally between both the schizophrenia and control group. Additionally, the amygdala, a candidate brain region from the extended system, was identified in nearly half the participants from both groups. These results indicate the effectiveness of a dynamic functional localizer at identifying regions of interest associated with face perception and emotion recognition in schizophrenia. The use of dynamic functional localizers may help standardize the investigation of the facial and emotion processing system in this and other clinical populations. [ABSTRACT FROM AUTHOR]

Which facets of human spatial navigation do sex and menstrual cycle influence? To answer this question, a cross-sectional online study of reproductive age women and men was conducted in which participants were asked to demonstrate and self-report their spatial navigation skills and strategies. Participants self-reported their sex and current menstrual phase [early follicular (EF), late follicular/periovulatory (PO), and mid/late luteal (ML)], and completed a series of questionnaires and tasks measuring self-reported navigation strategy use, topographical memory, cognitive map formation, face recognition, and path integration. We found that sex influenced self-reported use of cognitive map- and scene-based strategies, face recognition, and path integration. Menstrual phase moderated the influence of sex: compared to men, women had better face recognition and worse path integration, but only during the PO phase; PO women were also better at path integration in the presence of a landmark compared to EF + ML women and men. These findings provide evidence that human spatial navigation varies with the menstrual cycle and suggest that sensitivity of the entorhinal cortex and longitudinal axis of the hippocampus to differential hormonal effects may account for this variation. [ABSTRACT FROM AUTHOR]

ABSTRACT Developmental topographical disorientation (DTD) is a newly discovered cognitive disorder in which individuals experience a lifelong history of getting lost in both novel and familiar surroundings. Recent studies have shown that such a selective orientation defect relies primarily on the inability of the individuals to form cognitive maps, i.e., mental representations of the surrounding that allow individuals to get anywhere from any location in the environment, although other orientation skills are additionally affected. To date, the neural correlates of this developmental condition are unknown. Here, we tested the hypothesis that DTD may be related to ineffective functional connectivity between the hippocampus (HC; known to be critical for cognitive maps) and other brain regions critical for spatial orientation. A group of individuals with DTD and a group of control subjects underwent a resting-state functional magnetic resonance imaging (rsfMRI) scan. In addition, we performed voxel-based morphometry to investigate potential structural differences between individuals with DTD and controls. The results of the rsfMRI study revealed a decreased functional connectivity between the right HC and the prefrontal cortex (PFC) in individuals with DTD. No structural differences were detected between groups. These findings provide evidence that ineffective functional connectivity between HC and PFC may affect the monitoring and processing of spatial information while moving within an environment, resulting in the lifelong selective inability of individuals with DTD to form cognitive maps that are critical for orienting in both familiar and unfamiliar surroundings. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

variety of lesions in different cerebral regions may affect the human ability to orient in the environment, resulting in 'topographical disorientation'. In a recent study, we documented the first case of Developmental Topographical Disorientation (DTD), in a person with a life-long inability to orient despite otherwise well-preserved cognitive functions, and in the absence of a cerebral injury/malformation or other neurological condition. This selective topographical disorientation was due to her inability to form a 'cognitive map', a mental representation of the environment, which in turn impaired her ability to orient in both familiar and unfamiliar surroundings. Here, we describe 120 new cases of DTD recruited via the internet and assessed with an online battery testing their cognitive and orientation skills. We found that people with DTD differ from matched (age, gender and education) healthy controls only in those skills confined to the orientation/navigation domain, among which the ability to form a cognitive map was the most significant factor that distinguished a person affected by DTD from control subjects. [ABSTRACT FROM AUTHOR]

In this study, we report the case of a patient experiencing hallucinations of faces that could be reliably precipitated by looking at trees. Using functional Magnetic Resonance Imaging (fMRI), we found that face hallucinations were associated with increased and decreased neural activity in a number of cortical regions. Within the same fusiform face area, however, we found significant decreased and increased neural activity according to whether the patient was experiencing hallucinations or veridical perception of faces, respectively. These findings may indicate key differences in how hallucinatory and veridical perceptions lead to the same phenomenological experience of seeing faces. [ABSTRACT FROM AUTHOR]

Developmental topographical disorientation (DTD) refers to the lifelong inability to orient in extremely familiar surroundings despite the absence of any acquired brain damage or neurological disorder. Here, we describe the findings of this newly discovered condition, and highlight how this phenomenon provides novel insights into the mechanisms underlying human spatial navigation. [ABSTRACT FROM AUTHOR]

Functional localizers that contrast brain signal when viewing faces versus objects are commonly used in functional magnetic resonance imaging studies of face processing. However, current protocols do not reliably show all regions of the core system for face processing in all subjects when conservative statistical thresholds are used, which is problematic in the study of single subjects. Furthermore, arbitrary variations in the applied thresholds are associated with inconsistent estimates of the size of face-selective regions-of-interest (ROIs). We hypothesized that the use of more natural dynamic facial images in localizers might increase the likelihood of identifying face-selective ROIs in individual subjects, and we also investigated the use of a method to derive the statistically optimal ROI cluster size independent of thresholds. We found that dynamic facial stimuli were more effective than static stimuli, identifying 98% (versus 72% for static) of ROIs in the core face processing system and 69% (versus 39% for static) of ROIs in the extended face processing system. We then determined for each core face processing ROI, the cluster size associated with maximum statistical face-selectivity, which on average was approximately 50 mm3 for the fusiform face area, the occipital face area, and the posterior superior temporal sulcus. We suggest that the combination of (a) more robust face-related activity induced by a dynamic face localizer and (b) a cluster-size determination based on maximum face-selectivity increases both the sensitivity and the specificity of the characterization of face-related ROIs in individual subjects. Hum Brain Mapp 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Topographical orientation relies on the integrity of several cognitive functions and different strategies that individuals may adopt while navigating in the environment. Although previous studies have shown an age-related decline in navigational ability, these have not clarified the precise function or strategy that is affected. We hypothesized that aging may have an adverse effect on the ability to form and use a ‘cognitive map’, a mental representation of the environment. We had young and older participants solve a navigational task in a virtual environment designed to assess cognitive map use. Older participants required more time to form a cognitive map of the environment than young individuals and required more time and made more errors when subsequently using the cognitive map for orientation. These results suggest that decreased efficacy in both forming and using cognitive maps makes a significant contribution to the age-related decline in orientation skills. [Copyright &y& Elsevier]

Abstract: Topographical disorientation is the inability to orient within the environment, usually acquired from lesions to different cerebral regions participating in the attentional, perceptual or memory functions involved during navigation. We present the first case of a patient with topographical disorientation in the absence of any structural lesion and with intact sensory and intellectual function. Experimental tests in both real and virtual environments revealed a selective impairment in forming a mental representation of the environment, namely a cognitive map. Consistent with the patient''s behavioural findings, a functional magnetic resonance imaging (fMRI) study showed lack of activation in the hippocampal complex and the retrosplenial cortex while forming a cognitive map of the environment. Although the lack of neural activity results in a negative finding that generally has low interpretative value, in this specific case our findings may provide useful information. First, in a group of healthy control subjects performing the same task, activity within the hippocampal complex and retrosplenial cortex were detected in each individual participant. Second, we found that within the same regions (showing lack of neural activity while forming a cognitive map of the environment) increased neural activity was detected while the patient was performing a different navigation task. This case is the first evidence reported in the literature showing that topographical disorientation may occur as a developmental defect causing a lifelong disorder affecting daily activities. [Copyright &y& Elsevier]

Abstract: Several studies provide evidence that mental imagery is critical for human navigation. However, the contribution of different mental imagery abilities to the individuals’ skill of using specific orientation strategies remains unclear. In the present study we assessed a variety of mental imagery skills and investigated their contribution in relationship with the selective individuals’ ability of forming and using a mental representation of the environment, namely a cognitive map. Indeed, despite the use of alternative strategies that individuals may adopt while moving along the same well-known route, cognitive maps are critical for orientation since they allow individuals to reach any target location from any place in the environment. We found that the ability to form a cognitive map was related to the specific ability of performing mental rotations of simple geometrical shapes, and the ability to imaging ourselves moving on a map. Other imagery skills such as the ability to generate mental images from memory or the ability of mentally manipulate objects were not correlated with the individuals’ performance in forming the cognitive map. Moreover, we revealed gender differences in forming a cognitive map, as well as in performing some of the mental imagery tests. We discuss these findings in order to shed more light on the specific role of mental imagery in human topographical orientation. [Copyright &y& Elsevier]

Although a large body of evidence indicates that sleep plays an important role in learning and memory processes, the actual existence of a sleep-dependent spatial memory consolidation has been not firmly established. Here, by using a computerized 3D virtual navigation tool, we were able to show that topographical orientation in humans largely benefits from sleep after learning, while 10 h of wakefulness during the daytime do not exert similar beneficial effects. In particular, navigation performance enhancement needs sleep in the first post-training night, and no further improvements were seen after a second night of sleep. On the other hand, sleep deprivation hinders any performance enhancement and exerts a proactive disruption of spatial memory consolidation, since recovery sleep do not revert its effects. Spatial memory performance does not benefit from the simple passage of time, and a period of wakefulness between learning and sleep does not seem to have the role of stabilizing memory traces. In conclusion, our results indicate that spatial performance improvement is observed only when learning is followed by a period of sleep, regardless of the retention interval length. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Individuals vary widely in their ability to orient within the environment. We used diffusion tensor imaging to investigate whether this ability, as measured by navigational performance in a virtual environment, correlates with the anatomic structural properties of the hippocampus, i.e., fractional anisotropy. We found that individuals with high fractional anisotropy in the right hippocampus are (a) faster in forming a cognitive map of the environment, and (b) more efficient in using this map for the purpose of orientation, than individuals with low fractional anisotropy. These results are consistent with the role of the hippocampus in navigation, and suggest that its microstructural properties may contribute to the intersubject variability observed in spatial orientation. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Differences in personality factors between individuals may manifest themselves with different patterns of neural activity while individuals process stimuli with emotional content. We attempted to verify this hypothesis by investigating emotional susceptibility (ES), a specific emotional trait of the human personality defined as the tendency to 'experience feelings of discomfort, helplessness, inadequacy and vulnerability' after exposure to stimuli with emotional valence. By administering a questionnaire evaluating the individuals' ES, we selected two groups of participants with high and low ES respectively. Then, we used functional magnetic resonance imaging to investigate differences between the groups in the neural activity involved while they were processing emotional stimuli in an explicit (focusing on the content of the stimuli) or an incidental (focusing on spatial features of the stimuli, irrespectively of their content) way. The results showed a selective difference in brain activity between groups only in the explicit processing of the emotional stimuli: bilateral activity of the anterior insula was present in subjects with high ES but not in subjects with low ES. This difference in neural activity within the anterior insula proved to be purely functional since no brain morphological differences were found between groups, as assessed by a voxel-based morphometry analysis. Although the role of the anterior insula in the processing of contexts perceived as emotionally salient is well established, the present study provides the first evidence of a modulation of the insular activity depending on the individuals' ES trait of personality. Hum Brain Mapp, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Sex differences are often reported in spatial abilities. However, some studies show conflicting results, which can be ascribed to the complexity of the variables involved in the visuo-spatial domain. Until a few years ago, it was widely accepted that men outperformed women on almost all spatial tasks. However, recently some studies [A. Postma, G. Jager, R.P.C. Kessels, H.P.F. Koppeschaar, J. van Honk, Sex differences for selective forms of spatial memory, Brain Cogn. 54 (2004) 24–34; D.H. McBurney, S.J.C. Gaulin, T. Devineni, C. Adams, Superior spatial memory of women: stronger evidence for the gathering hypothesis, Evol. Hum. Behav. 18 (1997) 165–174; Q. Rahman, G.D. Wilson, S. Abrahams, Sexual orientation related differences in spatial memory, J. Int. Neuropsychol. Soc. 9 (2003) 376–383] found sex differences for selective forms of spatial memory and described a female advantage in specific spatial abilities. In this paper, we studied sex differences by testing object locations and route memories with the Corsi Block-Tapping test (CBT), one of the non-verbal tasks most used in clinical settings, and its modified, large-scale version. Our results showed a performance advantage for males in both tests and a more homogeneous pattern of memory in females. [Copyright &y& Elsevier]

Navigation is a complex cognitive ability requiring the processing and integration of several different types of information extracted from the environment. While navigating, however, an unexpected event may suddenly occur, which individuals are required to detect promptly in order to apply an appropriate behavioural response. The alerting mechanism that is integral to the detection of unexpected events is referred to as the bottom-up attentional system. Using event-related functional magnetic resonance imaging, we investigated the neural basis of bottom-up detection of unexpected events while individuals moved within a virtual environment. We identified activation within a right fronto-temporo-parietal network in response to unexpected events while navigating in this virtual environment. Furthermore, when an unexpected event requires an adjusted behavioural response, a region of the right ventrolateral pre-frontal cortex (areas 45 and 47/12) is selectively activated. Our data replicate earlier findings on the neural mechanisms underlying visual attention and extend these findings to the more complex real-life ability of spatial navigation, thereby suggesting that these neural mechanisms subserve the bottom-up attentional systems that are crucial for effective locomotion in real surroundings. [ABSTRACT FROM AUTHOR]

Despite decades of research, the question of whether the rapid eye movements (REMs) of paradoxical sleep (PS) are equivalent to waking saccades and whether their direction is congruent with visual spatial events in the dream scene is still very controversial. We gained an insight into these questions through the study of a right brain damaged patient suffering attentional neglect for the left side of space and drop of the optokinetic nystagmus (OKN) with alternating rightward slow/leftward fast phases evoked by rightward optic flow. During PS the patient had frequent Nystagmoid REMs with alternating leftward slow/rightward fast phases and reported dreams with visual events evoking corresponding OKN such as a train running leftward. By contrast, just as in waking OKN, Nystagmoid REMs with alternating rightward slow/leftward fast phases were virtually absent. REMs followed by staring eye position or by consecutive REMs were also observed: these showed no asymmetry comparable to that of Nystagmoid ones. The selective disappearance of Nystagmoid REMs in one horizontal direction proves, for the first time, that in humans different types of REMs exists and that these are driven by different premotor mechanisms. Concomitant drop of OKN and Nystagmoid REMs toward the same horizontal direction demonstrates that phylogenetically ancient oculomotor mechanisms, such as the OKN, are shared by waking and PS. On this evidence and converging findings from animal, neuropsychological and brain imaging studies, a new evolutionary account of dream bizarreness is proposed. Classification and labelling of the different types of REMs are also provided. [ABSTRACT FROM AUTHOR]

The ability to orientate within familiar environments relies on the formation and use of a mental representation of the environment, namely a cognitive map. Neuropsychological and neuroimaging studies suggest that the retrosplenial and hippocampal brain regions are involved in topographical orientation. We combined functional magnetic resonance imaging with a virtual-reality paradigm to investigate the functional interaction of the hippocampus and retrosplenial cortex during the formation and utilization of cognitive maps by human subjects. We found that the anterior hippocampus is involved during the formation of the cognitive map, while the posterior hippocampus is involved when using it. In conjunction with the hippocampus, the retrosplenial cortex was active during both the formation and the use of the cognitive map. In accordance with earlier studies in non-human animals, these findings suggest that, while navigating within the environment, the retrosplenial cortex complements the hippocampal contribution to topographical orientation by updating the individual's location as the frame of reference changes. [ABSTRACT FROM AUTHOR]

Abstract: Considerable evidence support the role of sleep in learning and memory processes. In rodents, the relationships between sleep and memory consolidation have been extensively investigated by taking into account mainly spatial learning. On the contrary, in humans the relationship between sleep and spatial memory consolidation has so far been scarcely taken into account. Here, we investigated the importance of sleep in the consolidation of the spatial memory traces of a new route learned in a real-life unfamiliar environment. Fifty-one subjects followed a defined route in a neighbourhood they had never been to before. Then, they were tested in the laboratory in a sequence-recognition test requiring them to evaluate whether or not sequences of three views, taken along the route, represented a correct sequential order as seen while walking along the route. Participants were then assigned to one of three groups: the sleep group was retested after one night''s sleep, the sleep-deprived group was retested after a night of sleep deprivation, and the day-control group was retested the same day after 8h of wakefulness. At retest, performance speed increased in all groups, whereas the accuracy in the sequence-recognition task was improved only in the sleep group: neither sleep deprivation nor the simple passage of time gave way to any performance improvement. These preliminary findings shed more light on the role of sleep in spatial memory consolidation by extending to humans the considerable evidence found in animals. [Copyright &y& Elsevier]

Topographical disorientation is usually described in patients who have lost the ability to orient themselves as a consequence of acquired focal brain damage. Here, we describe the case of a 20-year-old woman with a congenital brain malformation who has never been able to orient herself within the environment. We addressed in detail her ability to orient and navigate within the environment by administering a number of tasks in both ecological and experimental surroundings. The results indicate a complete inability to use any kind of strategy useful for orientation. [ABSTRACT FROM AUTHOR]

Presents a study that investigated the changes in human brain activity while adopting different strategies for navigating in space. Methods used; Assessment of test subject responses to the navigation strategies; Discussion of spontaneous variability and shift in neural mechanisms in the brain during navigation.

Individuals affected by Developmental Topographical Disorientation (DTD) get lost on a daily basis, even in the most familiar of surroundings such as their neighbourhood, the building where they have worked for many years, and, in extreme cases, even in their own homes. Individuals with DTD report a lifelong selective inability to orient despite otherwise well-preserved general cognitive functions, and the absence of any acquired brain injury or neurological condition, with general intelligence reported to be within the normal range. To date, the mechanisms underlying such a selective developmental condition remain unknown. Here, we report the findings of a 10-year-long study investigating the behavioural and cognitive mechanisms of DTD in a large sample of 1211 cases. We describe the demographics, heritability pattern, self-reported and objective spatial abilities, and some personality traits of individuals with DTD as compared to a sample of 1624 healthy controls; importantly, we test the specific hypothesis that the presence of DTD is significantly related to the inability of the individuals to form a mental representation of the spatial surroundings (i.e., a cognitive map). We found that individuals with DTD reported relatively greater levels of neuroticism and negative affect, and rated themselves more poorly on self-report measures of memory and imagery skills related to objects, faces, and places. While performing interactive tasks, as a group, the individuals with DTD performed slightly worse on a scene-based perspective-taking task, and, notably struggled to solve tasks that demand the generation and use of a cognitive map. These novel findings help define the phenotype of DTD, and lay the foundation for future studies of the neurological and genetic mechanisms of this lifelong condition. [ABSTRACT FROM AUTHOR]

Developmental topographical disorientation (DTD) refers to the lifelong inability to orient by means of cognitive maps in familiar surroundings despite otherwise well‐preserved general cognitive functions, and the absence of any acquired brain injury or neurological condition. While reduced functional connectivity between the hippocampus and other brain regions has been reported in DTD individuals, no structural differences in gray matter tissue for the whole brain neither for the hippocampus were detected. Considering that the human hippocampus is the main structure associated with cognitive map‐based navigation, here, we investigated differences in morphological and morphometric hippocampal features between individuals affected by DTD (N = 20) and healthy controls (N = 238). Specifically, we focused on a developmental anomaly of the hippocampus that is characterized by the incomplete infolding of hippocampal subfields during fetal development, giving the hippocampus a more round or pyramidal shape, called incomplete hippocampal inversion (IHI). We rated IHI according to standard criteria and extracted hippocampal subfield volumes after FreeSurfer's automatic segmentation. We observed similar IHI prevalence in the group of individuals with DTD with respect to the control population. Neither differences in whole hippocampal nor major hippocampal subfield volumes have been observed between groups. However, when assessing the IHI independent criteria, we observed that the hippocampus in the DTD group is more medially positioned comparing to the control group. In addition, we observed bigger hippocampal fissure volume for the DTD comparing to the control group. Both of these findings were stronger for the right hippocampus comparing to the left. Our results provide new insights regarding the hippocampal morphology of individuals affected by DTD, highlighting the role of structural anomalies during early prenatal development in line with the developmental nature of the spatial disorientation deficit. [ABSTRACT FROM AUTHOR]

The ability to navigate and orient in spatial surroundings is critical for effective daily functioning. Such ability is perturbed in clinically diagnosed mood and anxiety disorders, with patients exhibiting poor navigational skills. Here, we investigated the effects of depression and anxiety traits (not the clinical manifestation of the disorders) on the healthy population and hypothesized that greater levels of depression and anxiety traits would manifest in poorer spatial orientation skills and, in particular, with a poor ability to form mental representations of the environment, i.e., cognitive maps. We asked 1237 participants to perform a battery of spatial orientation tasks and complete two questionnaires assessing their anxiety and depression traits. Contrary to our hypothesis, we did not find any correlation between participants' anxiety and depression traits and their ability to form cognitive maps. These findings may imply a significant difference between the clinical and non-clinical manifestations of anxiety and depression as affecting spatial orientation and navigational abilities. [ABSTRACT FROM AUTHOR]

The retrosplenial complex is a region within the posterior cingulate cortex implicated in spatial navigation. Here, we investigated the functional specialization of this large and anatomically heterogeneous region using fMRI and resting-state functional connectivity combined with a spatial task with distinct phases of spatial 'updating' (i.e., integrating and maintaining object locations in memory during spatial displacement) and 'orienting' (i.e., recalling unseen locations from current position in space). Both spatial 'updating' and 'orienting' produced bilateral activity in the retrosplenial complex, among other areas. However, spatial 'updating' produced slightly greater activity in ventro-lateral portions, of the retrosplenial complex, whereas spatial 'orienting' produced greater activity in a more dorsal and medial portion of it (both regions localized along the parieto-occipital fissure). At rest, both ventro-lateral and dorso-medial subregions of the retrosplenial complex were functionally connected to the hippocampus and parahippocampus, regions both involved in spatial orientation and navigation. However, the ventro-lateral subregion of the retrosplenial complex displayed more positive functional connectivity with ventral occipital and temporal object recognition regions, whereas the dorso-medial subregion activity was more correlated to dorsal activity and frontal activity, as well as negatively correlated with more ventral parietal structures. These findings provide evidence for a dorso-medial to ventro-lateral functional specialization within the human retrosplenial complex that may shed more light on the complex neural mechanisms underlying spatial orientation and navigation in humans. [ABSTRACT FROM AUTHOR]

After completing a spaceflight, astronauts display a salient upward shift in the position of the brain within the skull, accompanied by a redistribution of cerebrospinal fluid. Magnetic resonance imaging studies have also reported local changes in brain volume following a spaceflight, which have been cautiously interpreted as a neuroplastic response to spaceflight. Here, we provide evidence that the grey matter volume changes seen in astronauts following spaceflight are contaminated by preprocessing errors exacerbated by the upwards shift of the brain within the skull. While it is expected that an astronaut's brain undergoes some neuroplastic adaptations during spaceflight, our findings suggest that the brain volume changes detected using standard processing pipelines for neuroimaging analyses could be contaminated by errors in identifying different tissue types (i.e., tissue segmentation). These errors may undermine the interpretation of such analyses as direct evidence of neuroplastic adaptation, and novel or alternate preprocessing or experimental paradigms are needed in order to resolve this important issue in space health research. [ABSTRACT FROM AUTHOR]

Navigating large-scale surroundings is a fundamental ability. In humans, it is commonly assumed that navigational performance is affected by individual differences, such as age, sex, and cognitive strategies adopted for orientation. We recently showed that the layout of the environment itself also influences how well people are able to find their way within it, yet it remains unclear whether differences in environmental complexity are associated with changes in brain activity during navigation. We used functional magnetic resonance imaging to investigate how the brain responds to a change in environmental complexity by asking participants to perform a navigation task in two large-scale virtual environments that differed solely in interconnection density, a measure of complexity defined as the average number of directional choices at decision points. The results showed that navigation in the simpler, less interconnected environment was faster and more accurate relative to the complex environment, and such performance was associated with increased activity in a number of brain areas (i.e. precuneus, retrosplenial cortex, and hippocampus) known to be involved in mental imagery, navigation, and memory. These findings provide novel evidence that environmental complexity not only affects navigational behaviour, but also modulates activity in brain regions that are important for successful orientation and navigation. [ABSTRACT FROM AUTHOR]

ABSTRACT The hypothesis that sleep is instrumental in the process of memory consolidation is currently largely accepted. Hippocampal formation is involved in the acquisition of declarative memories and particularly of spatial memories. Nevertheless, although largely investigated in rodents, the relations between spatial memory and hippocampal EEG activity have been scarcely studied in humans. Aimed to evaluate the effects of spatial learning on human hippocampal sleep EEG activity, we recorded hippocampal Stereo-EEG (SEEG) in a group of refractory epilepsy patients undergoing presurgical clinical evaluation, after a training on a spatial navigation task. We observed that hippocampal high-delta (2-4 Hz range) activity increases during the first NREM episode after learning compared to the baseline night. Moreover, the amount of hippocampal NREM high-delta power was correlated with task performance at retest. The effect involved only the hippocampal EEG frequencies inasmuch no differences were observed at the neocortical electrodes and in the traditional polysomnographic measures. The present findings support the crucial role of hippocampal slow EEG frequencies during sleep in the memory consolidation processes. More generally, together with previous results, they suggest that slow frequency rhythms are a fundamental characteristic of human hippocampal EEG during both sleep and wakefulness, and are related to the consolidation of different types of memories. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: The intraparietal sulcus (IPS) contains topographically organized regions, similar to retinotopic maps in visual cortex. These regions, referred to as IPS1–4, show similar functional responses to the mapping tasks used to define them, yet differing responses to tests of other posterior parietal cortex (PPC) functions such as short-term memory, eye movements and object viewing, suggesting that they may have distinct patterns of structural connectivity to other parts of the brain. The present study combined functional magnetic resonance imaging (fMRI) mapping with diffusion tensor imaging (DTI) to describe white matter connections of visuotopic regions along the IPS, in 25 neurotypical young-adult participants. We found that posterior IPS more likely connects to retinotopically defined visual regions, and superior temporal gyrus, relative to anterior IPS. Anterior IPS regions 3 and 4 had higher connection probabilities to prefrontal regions, relative to posterior IPS. All four IPS regions showed inter-hemispheric connections to analogous regions in the opposite hemisphere, as well as consistent connections to the thalamus and regions of the striatum. Multivariate pattern classification at the group level reliably distinguished IPS regions from one another on the basis of connectivity patterns, especially for the most distal pairs of regions; occipital and prefrontal regions provided the most discriminating information. These findings advance our understanding of the structure of visuotopic IPS, with implications for functional differences between regions, and possible homologies between humans and macaques. Visuospatial functions dependent on the parietal cortex are frequently impaired in individuals with developmental disorders and those afflicted by cerebrovascular disease; the findings described here can be used as a basis for comparing connectivity differences in these populations. [Copyright &y& Elsevier]

Abstract: Whether a single perceptual process or separate and possibly independent processes support facial identity and expression recognition is unclear. We used a morphed-face discrimination test to examine sensitivity to facial expression and identity information in patients with occipital or temporal lobe damage, and structural and functional MRI to correlate behavioral deficits with damage to the core regions of the face-processing network. We found selective impairments of identity perception in two patients with right inferotemporal lesions and two prosopagnosic patients with damage limited to the anterior temporal lobes. Of these four patients one exhibited damage to the right fusiform and occipital face areas, while the remaining three showed sparing of these regions. Thus impaired identity perception can occur with damage not only to the fusiform and occipital face areas, but also to other medial occipitotemporal structures that likely form part of a face recognition network. Impaired expression perception was seen in the fifth patient with damage affecting the face-related portion of the posterior superior temporal sulcus. This subject also had difficulty in discriminating identity when irrelevant variations in expression needed to be discounted. These neuropsychological and neuroimaging data provide evidence to complement models which address the separation of expression and identity perception within the face-processing network. [Copyright &y& Elsevier]

Although many cases of topographical disorientation are described in the literature, very few attempts have been made to rehabilitate this deficit, most likely because it is a multi-faceted syndrome in which different patients are affected by different topographical deficits. Therefore, it is not easy to develop a single rehabilitation programme to improve all types of topographical disorders. We describe the rehabilitation of a young woman with selective and pervasive topographical disorientation who never developed navigational skills due to a cerebral malformation bilaterally involving the retrorolandic regions. During treatment, the patient was trained to explore her surroundings carefully, to orient herself and then to move in the environment using a language-based strategy. At the end of the treatment, the patient was able to navigate in the environment by adopting several cognitive strategies useful for orientation. This result was maintained at the one-year follow-up, at which time the patient was also able to reach locations she had never been to alone. These results suggest that even patients who have never developed the ability to orient themselves in the environment can still achieve very good functional recovery if they are accurately assessed and submitted to a specific rehabilitation intervention. [ABSTRACT FROM AUTHOR]

Abstract: The recognition of facial identity and expression are distinct tasks, with current models hypothesizing anatomic segregation of processing within a face-processing network. Using fMRI adaptation and a region-of-interest approach, we assessed how the perception of identity and expression changes in morphed stimuli affected the signal within this network, by contrasting (a) changes that crossed categorical boundaries of identity or expression with those that did not, and (b) changes that subjects perceived as causing identity or expression to change, versus changes that they perceived as not affecting the category of identity or expression. The occipital face area (OFA) was sensitive to any structural change in a face, whether it was identity or expression, but its signal did not correlate with whether subjects perceived a change or not. Both the fusiform face area (FFA) and the posterior superior temporal sulcus (pSTS) showed release from adaptation when subjects perceived a change in either identity or expression, although in the pSTS this effect only occurred when subjects were explicitly attending to expression. The middle superior temporal sulcus (mSTS) showed release from adaptation for expression only, and the precuneus for identity only. The data support models where the OFA is involved in the early perception of facial structure. However, evidence for a functional overlap in the FFA and pSTS, with both identity and expression signals in both areas, argues against a complete independence of identity and expression processing in these regions of the core face-processing network. [Copyright &y& Elsevier]

Abstract: Topographical orientation relies on several cognitive strategies adopted by humans to move within the environment. In the present study, we investigate whether mental representation disorders affect specific cognitive mechanisms subserving human orientation. In order to differentiate distinct cognitive mechanisms involved in topographical orientation, we created a human version of the well-known “Morris Water Maze” and tested left and right brain damaged patients in a place-learning task. The test required the subjects to explore an experimental room in which no visual cues were present, find a target location, and then reach it in different conditions. The ability to memorise target locations in short- and long-term memory was also assessed. We found that all participants were able to reach the target location by using idiothetic cues (vestibular inputs, motor efferent copy, etc.). On the other hand, when starting position changed and re-orientation was necessary to reach the target location, in order to compute a new trajectory, only patients affected by representational neglect got lost. These results provide the first neuropsychological evidence of involvement of mental representation in a specific cognitive process allowing humans to reach a target place from any location in the environment. [Copyright &y& Elsevier]

Right brain damaged patients affected by left unilateral neglect (N+) typically fail to explore the contralesional space. For the first time, this study investigates the dynamic and spatial features of the horizontal vestibular–ocular response (VOR), the optokinetic response (OKR) and the VOR–OKR interaction in six N+ and in five right brain damaged patients without neglect (N−). No lateral asymmetry of the gain (i.e. eye velocity to head velocity ratio) of VOR slow phases was found in either group. In the VOR, N+ had higher frequency of slow-rightward/fast-leftward phases and higher contralesional shift of the beating field (i.e. orbital position of fast phases). In the VOR–OKR, there was an increase of gain in both lateral directions and in both groups even though in N−, there was a lower phase shift between eye and head velocity. In contrast to the VOR, in the VOR–OKR, N+ had higher frequency of slow-leftward/fast-rightward phases. The VOR–OKR interaction also introduced an ipsilesional shift of the beating field in both N+ and N−. In the OKR, N+ showed a drop in the velocity, amplitude and frequency of slow-rightward/fast-leftward phases. These findings potentially suggest that each hemisphere modulates VOR with contralaterally directed slow phases and OKR with ipsilaterally directed slow phases. This organisation could facilitate maintenance or fast recovery of combined VOR + OKR after unilateral brain damage. The same findings suggest that by inducing slow-leftward phases, vestibular and optokinetic stimulation improve left side neglect through the activation of different hemispheric pathways. No ipsilesional deviation of the subjective “straight ahead” was found in N+. These results show that chronic unilateral neglect can be dissociated both from deficits of ipsilesionally directed VOR and from ipsilesional deviation of the subjective midsagittal plane of the body. [Copyright &y& Elsevier]

Background: Older adults with bipolar disorder (BD) have increased dementia risk, but signs of dementia are difficult to detect in the context of pre-existing deficits inherent to BD.Objective: To identify the emergence of indicators of early dementia in BD.Methods: One hundred and fifty-nine non-demented adults with BD from the National Alzheimer's Coordinating Center (NACC) data repository underwent annual neuropsychological assessment up to 14 years (54.0 months average follow-up). Cognitive performance was examined longitudinally with linear mixed-effects models, and yearly differences between incident dementia cases and controls were examined in the six years prior to diagnosis.Results: Forty participants (25.2%) developed dementia over the follow-up period ('incident dementia cases'). Alzheimer's disease was the most common presumed etiology, though this was likely a result of sampling biases within NACC. Incident dementia cases showed declining trajectories in memory, language, and speeded attention two years prior to dementia onset.Conclusion: In a sample of BD patients enriched for Alzheimer's type dementia, prodromal dementia in BD can be detected up to two years before onset using the same cognitive tests used in psychiatrically-healthy older adults (i.e., measures of verbal recall and fluency). Cognition in the natural course of BD is generally stable, and impairment or marked decline on measures of verbal episodic memory or semantic retrieval may indicate an early neurodegenerative process. [ABSTRACT FROM AUTHOR]

The outbreak of COVID‐19 led to a reduction in the number of organ transplant interventions in most Countries. In April 2020, at the Tor Vergata University in Rome, Italy, two patients on the waiting list for kidney transplantation (KT) declined a deceased donor's kidney offer. Therefore, between April 20 and 25, 2020, we conducted a telephone survey among our 247 KT waitlist patients. Our aim was to explore: (a) the COVID‐19 diffusion among them and (b) their current willingness to be transplanted in case of a kidney offer from a deceased donor. Two hundred and forty‐three patients participated in a phone interview. One patient had died from COVID‐19. Eighty‐five (35%) KT candidates would decline any kidney offer, in most cases until the end of the COVID‐19 pandemic. Upon a multivariate analysis, female gender (OR = 2.25, 95% CI = 1.26‐4.03, P =.006), high cardiovascular risk (OR = 2.33, 95% CI = 1.06‐5.08, P =.034), a waiting list time <3 years (OR = 0.375, 95% CI = 0.15‐0.95, P =.04), and the need to be transferred to another hospital for HD (OR = 2.56, 95% CI = 1.10‐5.9, P =.03) were associated with such refusal. The COVID‐19 pandemic led to a fear of transplantation in a third of the KT candidates. Proactive educational webinars could be a useful tool to remove, or at least lessen, any doubts on the part of KT candidates and to avoid losing the opportunity to quit dialysis. [ABSTRACT FROM AUTHOR]

The concerns generated by coronavirus disease 2019 (COVID-19) pandemic are having profound impact on solid organ transplantation (SOT). Non-pharmaceutical interventions (NPI) are currently the only measures available to contain COVID-19 in the general population and in more vulnerable recipients of any organ transplant. In this cross-sectional case control study from a patient survey undertaken in 2 transplant centers (TxC) in the Kingdom of Saudi Arabia and Italy, we aimed to appraise awareness of the NPI implemented by respective these governments. We have also evaluated the impact of COVID-19 on our kidney transplant (KT) recipients and a control group of kidney living donors (KLD). In our series, there were zero cases of COVID-19 among 111 KT recipients and 70 KLD of the control group. Demography, transplant type, immunosuppression regimes, and, importantly, the different COVID-19 prevalence in the 2 regions of the TxC did not appear to influence incidence of COVID-19 in our KT recipients. The absence of COVID-19 cases in our series was unexpected. Our findings suggest that awareness of NPI is associated with a successful containment of COVID-19 in vulnerable, immunosuppressed KT recipients. [ABSTRACT FROM AUTHOR]

It is well known that our body works as a fundamental reference when we perform visuo-perceptual judgements in spatial surroundings, and that body illusions can modify our perception of size and distance of objects in space. To date, however, few studies have evaluated whether or not a body illusion could have a significant impact on the way individuals perceive to move within the environment. Here, we used a full-body illusion paradigm to verify the hypothesis that an altered representation of the legs of the individuals influences their time-to-walk estimation while imaging to reach objects in a virtual environment. To do so, we asked a group of young healthy volunteers to perform a task in which they were required to imagine walking towards a previously seen target location in a virtual environment, soon after receiving the body illusion; we required participants to use a response button to time their imagined walk from start to end. We found that participants imagined walking faster following the illusion elicited by the vision of longer legs presented from an anatomical perspective, as compared to when experiencing standard legs in the same position.This difference in imagined walking distance decreased when the object to reach was displayed farther, suggesting a fading effect. Furthermore, taking into consideration the baseline error in walking time estimation in VR, we noticed a specific influence of the long anatomical legs in reducing the perceived time needed to reach an object and a general increase in the percentage of error when the same legs are presented in a non-anatomical orientation. These findings provide evidence that body illusions could influence the way individuals perceive their locomotion in the spatial surrounding. [ABSTRACT FROM AUTHOR]

In this pilot study, we investigated the impact of a sport-related concussion (SRC) on the ability to form cognitive maps, mental representations of the environment that are critical for spatial orientation and navigation. We recruited 18 adolescent hockey players suffering from a SRC, and 19 age, sex and handedness-matched hockey players with no history of concussion. We asked participants to perform the Spatial Configuration Task (SCT), a computerized tool used to quantitatively measure the ability of the individuals to form cognitive maps. We found that athletes with a concussion performed significantly worse than controls on the SCT (F(1,34) = 5.82, p =.021, d ˆ = −0.72), confirming a negative effect of a SRC on the ability to form cognitive maps. We found no significant difference between groups in average response time, and no significant correlation between participants' performance at the SCT and reported symptoms of concussion as rated on the Sport Concussion Assessment Tool (SCAT5). Consistent with the integrity of extended neural networks required for effective spatial orientation and navigation, the findings of our pilot study provide preliminary evidence suggesting that a SRC may affect the ability to familiarize with a spatial surrounding and orient within it. [ABSTRACT FROM AUTHOR]

Although much is known about adults' ability to orient by means of cognitive maps (mental representations of the environment), it is less clear when this important ability emerges in development. In the present study, 97 seven- to 10-year-olds and 26 adults played a video game designed to investigate the ability to orient using cognitive maps. The game required participants to reach target locations as quickly as possible, necessitating the identification and use of novel shortcuts. Seven- and 8-year-olds were less effective than older children and adults in using shortcuts. These findings provide clear evidence of a distinct developmental change around 9 years of age when children begin to proficiently orient and navigate using cognitive maps. [ABSTRACT FROM AUTHOR]

Background. Empathy has been conceptualized as comprising a cognitive and an emotional component, the latter being further divided into direct and indirect aspects, which refer, respectively, to the explicit evaluation of the observer's feelings while attending someone in an emotional situation and to the physiological response of the observer. Empathy has been previously investigated in several neurological disorders. Objective. This study is aimed at investigating empathy in patients with spinal cord injury (SCI). We hypothesize that, due to deafferentation following their injury, SCI patients will display difficulty in the processing of emotional stimuli and blunted empathic responses as compared to healthy controls. Materials and Methods. 20 patients with spinal cord injury (SCI) (12 males and 8 females, mean age=50.9, standard deviation SD=16.1 years; mean education=10.9, SD=4.1 years) were included in the study and compared to 20 matched healthy subjects. Participants were investigated using the State-Trait Anxiety Inventory (Form Y) (STAI-Y), the Beck Depression Scale, and the Toronto Alexithymia Scale. Moreover, participants were further evaluated by means of the Interpersonal Reactivity Index (IRI), which explores both cognitive and emotional aspects of empathy, and through an experimental protocol based on the use of a modified version of the computerized Multifaceted Empathy Test (MET) to evaluate emotional (direct and indirect) empathy and the ability to judge the valence of complex emotional scenes. Results. As compared to healthy controls, SCI patients reported higher scores on the Perspective-Taking subscale of the IRI, while, on the modified MET, they were less accurate in identifying the valence of neutral scenes, notwithstanding their spared direct and indirect emotional empathy ability. Furthermore, we found a significant negative correlation between the time interval since injury and the direct emotional empathy scores on the positive images, as well as a negative correlation with the indirect emotional empathy scores on both positive and neutral images, indicating a blunting of the empathic responses as time elapses. Conclusion. Results suggest that SCI patients, when analyzing the meaning of emotional stimuli, tend to rely on a cognitive empathy strategy rather than on emotion simulation. [ABSTRACT FROM AUTHOR]

Abstract: The human ability to vicariously share someone else's emotions (i.e., emotional empathy) relies on an extended neural network including regions in the anterior cingulate and insular cortex. Here, we tested the hypothesis that good sleep quality is associated with increased activation in the brain areas underlying emotional empathy. To this aim, we assessed subjective sleep quality in a large sample of healthy young volunteers, and asked participants to complete a computerized emotional empathy task. Then, we asked 16 participants to complete the same task while undergoing functional Magnetic Resonance Imaging (fMRI). After confirming the behavioral relationship between quality of sleep and emotional empathy in the large sample, we conducted a Region of Interest (ROI) analysis on selected ROIs involved in emotional empathy, and measured Blood Oxygen Level Dependent (BOLD) signal change in participants who performed the emotional empathy task in the MRI scanner; additionally, we assessed how the BOLD signal in different brain areas temporally correlated with performance throughout the task (i.e., task‐based functional connectivity). We found increased BOLD signal change in a selective region within the left insula for individuals with better subjective sleep quality. These findings provide the very first evidence that individuals’ sleep quality relates to emotional empathic responses through increased neural activation of a specific area within the insular cortex. [ABSTRACT FROM AUTHOR]

The ability to experience emotional empathy is critical for vicariously sharing the emotional state of others. This important empathic skill is significantly affected by sleep deprivation and poor sleep quality. Here, we provide the very first evidence that experienced paramedics have a significantly reduced emotional empathy as compared to non-paramedic individuals and paramedic trainees, and that such effect is caused by their poor quality of sleep. Future research building on our findings could potentially lead to an improvement of work conditions, shifts schedules, and resiliency training for paramedics, which would ultimately benefit all users of emergency medical services. [ABSTRACT FROM AUTHOR]

As a focal injury in an otherwise healthy child, perinatal stroke provides a clinical model of developmental brain plasticity. In this study, we report evidence that children with perinatal periventricular venous infarcts perform as well as control children on a video game that tests navigation abilities. In addition, children with a history of perinatal arterial strokes overcame initial deficits in navigation performance after additional practice. These findings lend support to the hypothesis that a complex cognitive skill dependent on a distributed neural network with prolonged maturation, such as navigation, may demonstrate resilience after early brain injury. [ABSTRACT FROM PUBLISHER]

Incidence of malignant tumors in kidney transplant recipients is higher than nontransplanted population due to many factors, such as immunosuppression therapy and complex donor-recipient interaction. Genitourinary malignancies have been reported as the second most common malignancy in kidney transplant recipients. In this regard, prostate cancer is the most common neoplasm. Herein, we describe a rare case of prostate cancer recurrence after 15 years in a patient who underwent kidney transplant after radical prostatectomy. [ABSTRACT FROM AUTHOR]

A variety of brain lesions may affect the ability to orient, resulting in what is termed “acquired topographical disorientation”. In some individuals, however, topographical disorientation is present from childhood, with no apparent brain abnormalities and otherwise intact general cognitive abilities, a condition referred to as “developmental topographical disorientation” (DTD). Individuals affected by DTD often report relatives experiencing the same lifelong orientation difficulties. Here, we sought to assess the familial aggregation of DTD by investigating its occurrence in the families of DTD probands, and in the families of control probands who did not experience topographical disorientation. We found that DTD appears to cluster in the DTD families, with tested relatives displaying the trait, whereas in the control families we did not detect any individuals with DTD. These findings provide the very first evidence for the familial clustering of DTD and motivate further work investigating the genetic factors producing this clustering. [ABSTRACT FROM AUTHOR]

The article presents a study related to the investigation of the neural correlates of emotional empathy dysfunction to shed light on the neural circuitry responsible for the social and emotional dysfunction in Post-Traumatic Stress Disorder (PTSD). It mentions about a group of healthy controls to solve a Multifaceted Empathy Test. It states increased activity in limbic regions during PTSD.

Video games are a popular form of entertainment, but computerized tasks, often resembling video games or built off of video game platforms, are increasingly being used in research. Previous studies have indicated a correlation between video game use and performance on many virtual tasks, including tasks of navigation and orientation. By more completely characterizing previous video game experience and controlling for increased dexterity with game controls, this study endeavored to clarify the nature of such improvements in performance. The findings confirmed that individuals with a longer history of video game play have better performance on a virtual navigation task; however, this effect was greatest in players of video games with a navigational component, and it was not due solely to better use of game controls. Furthermore, participants who play navigational video games more often reported using more efficient navigational strategies, such as using cognitive maps or adopting procedural approaches through learned routes. The findings reported in this study provide evidence that better navigation and topographical orientation skills in individuals playing video games are likely due to the consistent practice of those skills while playing for the purpose of entertainment. [ABSTRACT FROM AUTHOR]