Ford Burles

Cognitive mapping in humans and its relationship to other orientation skills

Human orientation in novel and familiar environments is a complex skill that can involve numerous different strategies. To date, a comprehensive account of how these strategies interrelate at the behavioural level has not been documented, impeding the development of elaborate systems neuroscience models of spatial orientation. Here, we describe a virtual environment test battery designed to assess five of the core strategies used by humans to orient. Our results indicate that the ability to form a cognitive map is highly related to more basic orientation strategies, supporting previous proposals that encoding a cognitive map requires inputs from multiple domains of spatial processing. These findings provide a topology of numerous primary orientation strategies used by humans during orientation and will allow researchers to elaborate on neural models of spatial cognition that currently do not account for how different orientation strategies integrate over time based on environmental conditions.

The effects of sleep deprivation on emotional empathy

Previous studies have shown that sleep loss has a detrimental effect on the ability of the individuals to process emotional information. In this study, we tested the hypothesis that this negative effect extends to the ability of experiencing emotions while observing other individuals, i.e. emotional empathy. To test this hypothesis, we assessed emotional empathy in 37 healthy volunteers who were assigned randomly to one of three experimental groups: one group was tested before and after a night of total sleep deprivation (sleep deprivation group), a second group was tested before and after a usual night of sleep spent at home (sleep group) and the third group was tested twice during the same day (day group). Emotional empathy was assessed by using two parallel versions of a computerized test measuring direct (i.e. explicit evaluation of empathic concern) and indirect (i.e. the observers reported physiological arousal) emotional empathy. The results revealed that the post measurements of both direct and indirect emotional empathy of participants in the sleep deprivation group were significantly lower than those of the sleep and day groups; post measurement scores of participants in the day and sleep groups did not differ significantly for either direct or indirect emotional empathy. These data are consistent with previous studies showing the negative effect of sleep deprivation on the processing of emotional information, and extend these effects to emotional empathy. The findings reported in our study are relevant to healthy individuals with poor sleep habits, as well as clinical populations suffering from sleep disturbances.

Developmental topographical disorientation and decreased hippocampal functional connectivity

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.

Differential neural network configuration during human path integration

Path integration is a fundamental skill for navigation in both humans and animals. Despite recent advances in unraveling the neural basis of path integration in animal models, relatively little is known about how path integration operates at a neural level in humans. Previous attempts to characterize the neural mechanisms used by humans to visually path integrate have suggested a central role of the hippocampus in allowing accurate performance, broadly resembling results from animal data. However, in recent years both the central role of the hippocampus and the perspective that animals and humans share similar neural mechanisms for path integration has come into question. The present study uses a data driven analysis to investigate the neural systems engaged during visual path integration in humans, allowing for an unbiased estimate of neural activity across the entire brain. Our results suggest that humans employ common task control, attention and spatial working memory systems across a frontoparietal network during path integration. However, individuals differed in how these systems are configured into functional networks. High performing individuals were found to more broadly express spatial working memory systems in prefrontal cortex, while low performing individuals engaged an allocentric memory system based primarily in the medial occipito-temporal region. These findings suggest that visual path integration in humans over short distances can operate through a spatial working memory system engaging primarily the prefrontal cortex and that the differential configuration of memory systems recruited by task control networks may help explain individual biases in spatial learning strategies.

Getting lost: Topographic skills in acquired and developmental prosopagnosia

Previous studies report that acquired prosopagnosia is frequently associated with topographic disorientation. Whether this is associated with a specific anatomic subtype of prosopagnosia, how frequently it is seen with the developmental variant, and what specific topographic function is impaired to account for this problem are not known. We studied ten subjects with acquired prosopagnosia from either occipitotemporal or anterior temporal (AT) lesions and seven with developmental prosopagnosia. Subjects were given a battery of topographic tests, including house and scene recognition, the road map test, a test of cognitive map formation, and a standardized self-report questionnaire. House and/or scene recognition were frequently impaired after either occipitotemporal or AT lesions in acquired prosopagnosia. Subjects with occipitotemporal lesions were also impaired in cognitive map formation: an overlap analysis identified right fusiform and parahippocampal gyri as a likely correlate. Only one subject with acquired prosopagnosia had mild difficulty with directional orientation on the road map test. Only one subject with developmental prosopagnosia had difficulty with cognitive map formation, and none were impaired on the other tests. Scores for house and scene recognition correlated most strongly with the results of the questionnaire. We conclude that topographic disorientation in acquired prosopagnosia reflects impaired place recognition, with a contribution from poor cognitive map formation when there is occipitotemporal damage. Topographic impairments are less frequent in developmental prosopagnosia.

Floor Plan Connectivity Influences Wayfinding Performance in Virtual Environments

The structure of the physical environment can have a significant influence on individuals’ ability to orient within it. We asked participants to perform a cued wayfinding task in two virtual environments to test the hypothesis that spatial orientation skills are indeed affected by the physical complexity of the environment. The two virtual environments used for testing differed solely in one objective measure of plan complexity, that is, the average number of connections at each decision point or terminal corridor. Our results showed that participants committed more errors and took longer to reach their destinations in the more interconnected environment. Performance was more efficient on trials in which participants were able to use previously learned routes relative to trials in which participants were forced to plan novel routes. These findings provide strong evidence that people’s ability to navigate in unfamiliar surroundings is affected by the layout complexity of the environment.

Developmental Topographical Disorientation

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.

Neuroticism and self-evaluation measures are related to the ability to form cognitive maps critical for spatial orientation.

Trait neuroticism is suggested to be related to measures of volume and function of the hippocampus, a brain structure located in the medial temporal lobe that is critical for human navigation and orientation. In this study, we assessed whether measures of trait neuroticism and self-concept are correlated with the human ability to orient by means of cognitive maps (i.e. mental representations of an environment that include landmarks and their spatial relationships). After controlling for gender differences, which are well-known in spatial orientation abilities, we found that measures of neuroticism (i.e. negative affect, emotional stability) and self-concept (i.e. self-esteem) were correlated with individual differences in the rate at which cognitive maps were formed; the same measures were generally unrelated to the ability to make use of cognitive maps, as well as the ability to orient using visual path integration. The relationships (and lack thereof) between personality traits and the spatial orientation skills, as reported in the present study, are consistent with specific neural correlates underlying these factors, and may have important implications for treatment of disorders related to them.

Environmental layout complexity affects neural activity during navigation in humans

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.

The Relationship Between Quality of Sleep and Emotional Empathy

Sleep loss is known to severely disturb individuals’ mood and emotion processing. Here, we tested the hypothesis that quality of sleep is predictive of individuals’ performance on a task evaluating emotional empathy. We tested 34 healthy undergraduate students [19 males, mean (SD) age = 21.82 (3.26) years; mean (SD) education = 14.98 (1.91) years] recruited through the University of Calgary research participation system. We collected objective (actigraphy) and subjective (questionnaires and self-reports) sleep measures to characterize individuals’ sleep quality, and asked participants to solve a computerized emotional empathy task. We first performed a dimensionality reduction analysis on the sleep-related measures, which resulted in six principal components, and then ran a stepwise multiple regression analysis to investigate the sleep measures that best predicted participants’ scores on the emotional empathy task. We found that subjective sleep quality, together with sleep phase, best predicted participants’ empathic sensitivity to negative images while they explicitly evaluated the emotions of others (i.e., direct component of emotional empathy). Also, subjective sleep quality resulted to be the best predictor of participants’ arousal state in response to negative images, which is an implicit manifestation of their empathic experience (i.e., indirect component of emotional empathy). In both cases, lower subjective sleep quality was associated with lower empathic sensitivity to negative stimuli. Finally, sleep duration best predicted average empathic responses to stimuli of all valences, with shorter sleep durations associated with lower average empathic responses. Our findings provide evidence of a significant relationship between individuals’ quality of sleep and their ability to share the emotions experienced by others. These findings may have important implications for individuals employed in professions requiring social interaction and empathic experience coupled with schedules that interfere with nighttime sleep.