Entropy of city street networks linked to future spatial navigation ability.

The cultural and geographical properties of the environment have been shown to deeply influence cognition and mental health1-6. Living near green spaces has been found to be strongly beneficial7-11, and urban residence has been associated with a higher risk of some psychiatric disorders12-14-although some studies suggest that dense socioeconomic networks found in larger cities provide a buffer against depression15. However, how the environment in which one grew up affects later cognitive abilities remains poorly understood. Here we used a cognitive task embedded in a video game16 to measure non-verbal spatial navigation ability in 397,162 people from 38 countries across the world. Overall, we found that people who grew up outside cities were better at navigation. More specifically, people were better at navigating in environments that were topologically similar to where they grew up. Growing up in cities with a low street network entropy (for example, Chicago) led to better results at video game levels with a regular layout, whereas growing up outside cities or in cities with a higher street network entropy (for example, Prague) led to better results at more entropic video game levels. This provides evidence of the effect of the environment on human cognition on a global scale, and highlights the importance of urban design in human cognition and brain function.

No link between handedness and spatial navigation: evidence from over 400 000 participants in 41 countries.

There is an active debate concerning the association of handedness and spatial ability. Past studies used small sample sizes. Determining the effect of handedness on spatial ability requires a large, cross-cultural sample of participants and a navigation task with real-world validity. Here, we overcome these challenges via the mobile app Sea Hero Quest. We analysed the navigation performance from 422 772 participants from 41 countries and found no reliable evidence for any difference in spatial ability between left- and right-handers across all countries. A small but growing gap in performance appears for participants over 64 years old, with left-handers outperforming right-handers. Further analysis, however, suggests that this gap is most likely due to selection bias. Overall, our study clarifies the factors associated with spatial ability and shows that left-handedness is not associated with either a benefit or a deficit in spatial ability.

Cultural determinants of the gap between self-estimated navigation ability and wayfinding performance: evidence from 46 countries.

Cognitive abilities can vary widely. Some people excel in certain skills, others struggle. However, not all those who describe themselves as gifted are. One possible influence on self-estimates is the surrounding culture. Some cultures may amplify self-assurance and others cultivate humility. Past research has shown that people in different countries can be grouped into a set of consistent cultural clusters with similar values and tendencies, such as attitudes to masculinity or individualism. Here we explored whether such cultural dimensions might relate to the extent to which populations in 46 countries overestimate or underestimate their cognitive abilities in the domain of spatial navigation. Using the Sea Hero Quest navigation test and a large sample (N = 383,187) we found cultural clusters of countries tend to be similar in how they self-rate ability relative to their actual performance. Across the world population sampled, higher self-ratings were associated with better performance. However, at the national level, higher self-ratings as a nation were not associated with better performance as a nation. Germanic and Near East countries were found to be most overconfident in their abilities and Nordic countries to be most under-confident in their abilities. Gender stereotypes may play a role in mediating this pattern, with larger national positive attitudes to male stereotyped roles (Hofstede's masculinity dimension) associated with a greater overconfidence in performance at the national level. We also replicate, with higher precision than prior studies, evidence that older men tend to overestimate their navigation skill more than other groups. These findings give insight into how culture and demographics may impact self-estimates of our abilities.

Entropy and a sub-group of geometric measures of paths predict the navigability of an environment.

Despite extensive research on navigation, it remains unclear which features of an environment predict how difficult it will be to navigate. We analysed 478,170 trajectories from 10,626 participants who navigated 45 virtual environments in the research app-based game Sea Hero Quest. Virtual environments were designed to vary in a range of properties such as their layout, number of goals, visibility (varying fog) and map condition. We calculated 58 spatial measures grouped into four families: task-specific metrics, space syntax configurational metrics, space syntax geometric metrics, and general geometric metrics. We used Lasso, a variable selection method, to select the most predictive measures of navigation difficulty. Geometric features such as entropy, area of navigable space, number of rings and closeness centrality of path networks were among the most significant factors determining the navigational difficulty. By contrast a range of other measures did not predict difficulty, including measures of intelligibility. Unsurprisingly, other task-specific features (e.g. number of destinations) and fog also predicted navigation difficulty. These findings have implications for the study of spatial behaviour in ecological settings, as well as predicting human movements in different settings, such as complex buildings and transport networks and may aid the design of more navigable environments.

Sleep targets highly connected global and local nodes to aid consolidation of learned graph networks.

Much of our long-term knowledge is organised in complex networks. Sleep is thought to be critical for abstracting knowledge and enhancing important item memory for long-term retention. Thus, sleep should aid the development of memory for networks and the abstraction of their structure for efficient storage. However, this remains unknown because past sleep studies have focused on discrete items. Here we explored the impact of sleep (night-sleep/day-wake within-subject paradigm with 25 male participants) on memory for graph-networks where some items were important due to dense local connections (degree centrality) or, independently, important due to greater global connections (closeness/betweenness centrality). A network of 27 planets (nodes) sparsely interconnected by 36 teleporters (edges) was learned via discrete associations without explicit indication of any network structure. Despite equivalent exposure to all connections in the network, we found that memory for the links between items with high local connectivity or high global connectivity were better retained after sleep. These results highlight that sleep has the capacity for strengthening both global and local structure from the world and abstracting over multiple experiences to efficiently form internal networks of knowledge.

Reported sleep duration reveals segmentation of the adult life-course into three phases.

Classically the human life-course is characterized by youth, middle age and old age. A wide range of biological, health and cognitive functions vary across this life-course. Here, using reported sleep duration from 730,187 participants across 63 countries, we find three distinct phases in the adult human life-course: early adulthood (19-33yrs), mid-adulthood (34-53yrs), and late adulthood (54+yrs). They appear stable across culture, gender, education and other demographics. During the third phase, where self-reported sleep duration increases with age, cognitive performance, as measured by spatial navigation, was found to have an inverted u-shape relationship with reported sleep duration: optimal performance peaks at 7 hours reported sleep. World-wide self-reported sleep duration patterns are geographically clustered, and are associated with economy, culture, and latitude.

Augmenting ENT surgery outside the medical school curriculum: the role of a 1-day otolaryngology course.

BACKGROUND: ENT is highly under-represented in the saturated UK medical school curriculum, comprising less than 1 per cent of the curriculum. A 1-day course was implemented in order to raise awareness of ENT among medical students, educate them in the specialty and teach a basic skill. METHODS: The skills day comprised lectures by consultants followed by a consultant-led workshop teaching tracheostomy. Pre- and post-course questionnaires assessed perceptions of ENT, confidence performing tracheostomy and interest in ENT as a career. RESULTS: Perceptions of ENT as a specialty were improved by up to 80 per cent (p < 0.01). There was improved understanding of and confidence in performing tracheostomies. Interest in a career in ENT was increased by 77 per cent (p < 0.01). CONCLUSION: A 1-day course run by a student body can be a powerful adjunct to the medical school curriculum, in terms of educating undergraduates in ENT and inspiring the pursuit of ENT as a career.

The neuroscience of remote spatial memory: a tale of two cities.

Most of our everyday activities take place in familiar environments learned in the past which we need to constantly navigate. Despite our obvious reliance on these remote spatial memories, until quite recently relatively little was known about how they are instantiated in the human brain. Here we will consider developments in the neuropsychological and neuroimaging domains where innovative methodologies and novel analysis techniques are providing new opportunities for exploring the brain dynamics underpinning the retrieval and use of remotely learned spatial information. These advances allow three key questions to be considered anew: What brain areas in humans support the retrieval and use of remotely learned spatial information? Where in the brain are spatial memories stored? Do findings relating to remote spatial memory inform theoretical debates about memory consolidation? In particular, the hippocampus, parahippocampus, retrosplenial and parietal cortices are scrutinized, revealing new insights into their specific contributions to representing spaces and places from the past.

Human Navigation: Occipital Place Area Detects Potential Paths in a Scene.

Navigation - determining how to get from where you are to somewhere else - has obvious importance for the survival of motile animals. A new neuroimaging study has revealed that, in the human brain, the occipital place area detects the number of possible paths in a vista.

Advanced paternal age effects in neurodevelopmental disorders-review of potential underlying mechanisms.

Multiple epidemiological studies suggest a relationship between advanced paternal age (APA) at conception and adverse neurodevelopmental outcomes in offspring, particularly with regard to increased risk for autism and schizophrenia. Conclusive evidence about how age-related changes in paternal gametes, or age-independent behavioral traits affect neural development is still lacking. Recent evidence suggests that the origins of APA effects are likely to be multidimensional, involving both inherited predisposition and de novo events. Here we provide a review of the epidemiological and molecular findings to date. Focusing on the latter, we present the evidence for genetic and epigenetic mechanisms underpinning the association between late fatherhood and disorder in offspring. We also discuss the limitations of the APA literature. We propose that different hypotheses relating to the origins of the APA effects are not mutually exclusive. Instead, multiple mechanisms likely contribute, reflecting the etiological complexity of neurodevelopmental disorders.

Path integration following temporal lobectomy in humans.

Path integration, a component of spatial navigation, is the process used to determine position information on the basis of information about distance and direction travelled derived from self-motion cues. Following on from studies in the animal literature that seem to support the role of the hippocampal formation in path integration, this facility was investigated in humans with focal brain lesions. Thirty-three neurosurgical patients (17 left temporal lobectomy, LTL; 16 right temporal lobectomy, RTL) and 16 controls were tested on a number of blindfolded tasks designed to investigate path integration and on a number of additional control tasks (assessing mental rotation and left-right orientation). In a test of the ability to compute a homing vector, the subjects had to return to the start after being led along a route consisting of two distances and one turn. Patients with RTL only were impaired at estimating the turn required to return to the start. On a second task, route reproduction was tested by requiring the subjects to reproduce a route consisting of two distances and one turn; the RTL group only were also impaired at reproducing the turn, but this impairment did not correlate with the homing vector deficit. There were no group differences on tasks where subjects were required to reproduce a single distance or a single turn. The results indicate that path integration is impaired in RTL patients only and suggest that the right temporal lobe plays a role in idiothetic spatial memory.

AIDS and civil disobedience.

KIE: Members of groups such as ACT UP (AIDS Coalition to Unleash Power) risk arrest and criminal charges to protest laws and policies they view as unjust to persons with AIDS. Spiers, a founding member of ACT UP, discusses the rationale behind the tactics of civil disobedience employed by AIDS activists. He argues that civil disobedience is justified by American political and legal traditions, and by the federal government's lack of response to the needs of its citizens. Spiers warns that while AIDS protests have been nonviolent and characterized by conscientious planning and execution, violence cannot be ruled out as a "political act born of desperation."^ieng

Communication. Clarity begins at home.

The NHS's failure to use plain English is a long-standing and widely acknowledged problem. Most people get their information from tabloid newspapers, where sentences have 30 words or fewer. Patients should be involved in the preparation of patient information leaflets. The government's emphasis on involving the public in the NHS, and holding board meetings in public, will be meaningless unless briefing papers can be understood.

Joint working. Dancing with wolves?

A formalised and closer strategic partnership between a health authority and the healthcare industry has brought benefits to both sides. Joint working with seven companies has been used to develop an osteoporosis framework for the district, resulting in distribution of a comprehensive resource pack. Lessons have been learned on the way, and the project is being evaluated.

Anterior prefrontal involvement in episodic retrieval reflects contextual interference.

Different patterns of prefrontal activation are commonly found in studies of episodic and source memory (typically anterior and lateral) compared to those found in studies of autobiographical memory (typically ventromedial). We investigated a proposal that the former pattern reflects contextual interference when retrieving events that occurred in similar contexts. We used virtual reality to simulate contextually varied life-like events, in which subjects received distinct objects from a number of people in a number of locations. We compared fMRI data from two experiments in which the number of events per context varied. The first experiment (Burgess, N., Maguire, E.A., Spiers, H.J., and O'Keefe, J. 2001. A temporoparietal and prefrontal network for retrieving the spatial context of lifelike events. Neuroimage 14, 439-453) involved 16 objects received from one of two people in one of two locations. The second experiment involved 20 objects, each received from a different person in a different location. The first experiment showed extensive bilateral activation of anterior and lateral prefrontal cortex, as well as a medial temporal and parietal network characteristic of both autobiographical and episodic memory. In the second study, the prefrontal activations were largely absent, while the medial parietal and temporal activations remained, and a ventromedial prefrontal area was additionally activated. Direct comparisons revealed large areas of significantly reduced activation in BA10, with lesser reductions in lateral prefrontal regions. We suggest that involvement of these prefrontal regains in episodic and source memory reflects the use of paradigms involving many events and few sources rather than any fundamental processing requirement of contextual retrieval in the absence of interference.

Hippocampal amnesia.

This article reviews 147 cases of amnesia following damage including the hippocampus or fornix as reported in 179 publications. The aetiology, mnestic abilities and reference(s) are tabulated for each case. Consistent findings across cases include the association of bilateral hippocampal damage with a deficit in anterograde episodic memory combined with spared procedural and working memory. The limited nature of retrograde amnesia following lesions to the fornix is also noted. Less consistent and thus more controversial findings, include effects of lesion size or laterality, deficits in semantic memory or familiarity-based recognition and the extent of retrograde amnesia. The evidence concerning these issues is reviewed across cases.

Bilateral hippocampal pathology impairs topographical and episodic memory but not visual pattern matching.

A virtual reality environment was used to test memory performance for simulated "real-world" spatial and episodic information in a 22-year-old male, Jon, who has selective bilateral hippocampal pathology caused by perinatal anoxia. He was allowed to explore a large-scale virtual reality town and was then tested on his memory for spatial layout and for episodes experienced. Topographical memory was tested by assessing his ability to navigate, recognize previously visited locations, and draw maps of the town. Episodic memory was assessed by testing the retrieval of simulated events which consisted of collecting objects from characters while following a route through the virtual town. Memory for the identity of objects, as well as for where they were collected, from whom, and in what order, was also tested. While the first task tapped simple recognition memory, the latter three tested memory for context. Jon was impaired on all topographical tasks and on his recall of the context-dependent questions. However, his recognition of objects from the virtual town, and of "topographical" scenes (as evaluated by standard neuropsychological tests), was not impaired. These findings are consistent with the view that the hippocampus is involved in navigation, recall of long term allocentric spatial information and context-dependent episodic memory, but not visual pattern matching.