The relationship between object-based spatial ability and virtual navigation performance.

Spatial navigation is a multi-faceted behaviour drawing on many different aspects of cognition. Visuospatial abilities, such as mental rotation and visuospatial working memory, in particular, may be key factors. A range of tests have been developed to assess visuospatial processing and memory, but how such tests relate to navigation ability remains unclear. This understanding is important to advance tests of navigation for disease monitoring in various disorders (e.g., Alzheimer's disease) where spatial impairment is an early symptom. Here, we report the use of an established mobile gaming app, Sea Hero Quest (SHQ), as a measure of navigation ability in a sample of young, predominantly female university students (N = 78; 20; female = 74.3%; mean age = 20.33 years). We used three separate tests of navigation embedded in SHQ: wayfinding, path integration and spatial memory in a radial arm maze. In the same participants, we also collected measures of mental rotation (Mental Rotation Test), visuospatial processing (Design Organization Test) and visuospatial working memory (Digital Corsi). We found few strong correlations across our measures. Being good at wayfinding in a virtual navigation test does not mean an individual will also be good at path integration, have a superior memory in a radial arm maze, or rate themself as having a strong sense of direction. However, we observed that participants who were good in the wayfinding task of SHQ tended to perform well on the three visuospatial tasks examined here, and to also use a landmark strategy in the radial maze task. These findings help clarify the associations between different abilities involved in spatial navigation.

Intrusive prospective imagery, posttraumatic intrusions and anxiety in schizophrenia.

Trauma exposure and intrusive thoughts are commonly reported in both schizophrenia and posttraumatic stress disorder (PTSD). Information processing accounts suggest that intrusions occur in the two conditions as a result of insufficient state and/or trait contextual processing in long-term memory. Most research has focused on intrusions about past events, while growing evidence suggests that intrusions about prospective imagined events warrants further investigation. Prospective intrusive imagery has yet to be examined in psychotic disorders but could provide crucial information regarding the aetiology and maintenance of psychotic symptoms. The current study examines the role of prospective intrusive imagery, posttraumatic intrusions and anxiety in schizophrenia. Fifty-seven participants (30 patients and 27 healthy controls) completed measures of trauma, PTSD, anxiety, general non-affective use of imagery, and intrusive prospective imagery. Patients reported significantly more intrusive prospective imagery relative to control participants but, importantly, not greater use of general non-affective imagery. Intrusive prospective imagery was associated with posttraumatic intrusions and anxiety in schizophrenia. The findings are consistent with information processing models of intrusions and psychosis, and provide novel insights for theoretical accounts, clinical formulation and therapeutic targets for psychotic symptoms in schizophrenia.

Chronologically organized structure in autobiographical memory search.

Each of us has a rich set of autobiographical memories that provides us with a coherent story of our lives. These memories are known to be highly structured both thematically and temporally. However, it is not known how we naturally tend to explore the mental timeline of our memories. Here we developed a novel cued retrieval paradigm in order to investigate the temporal element of memory search. We found that, when asked to search for memories in the days immediately surrounding a salient cued event, participants displayed a marked set of temporal biases in their search patterns. Specifically, participants first tended to jump back in time and retrieve memories from the day prior to the cued event. Following this they then transitioned forward in time, and retrieved memories from the day after the cued event. This pattern of results replicated in a second experiment with a much larger group of participants, and a different method of cueing the memories. We argue that this set of temporal biases is consistent with memory search conforming to a temporally ordered narrative structure.

Pre-morbid Conduct Disorder symptoms are associated with cannabis use among individuals with a first episode of psychosis.

BACKGROUND: Early cannabis use has consistently been associated with an increased risk for the later development of psychosis. Studies suggest that Conduct Disorder (CD) is more common amongst young people who later go on to develop psychosis. CD has been associated with greater and earlier cannabis use in general population samples. Based on this evidence, we hypothesised that among patients experiencing their first episode of psychosis, the presence of CD symptoms prior to age 15 would be associated with cannabis use. METHOD: 102 patients experiencing a first episode of psychosis were interviewed to assess CD symptoms prior to age 15 and use of cannabis and other substances. RESULTS: The number of CD symptoms was significantly associated with lifetime cannabis use (odds ratio=5.41 (1.76-16.57), p=0.03) and with first use of cannabis before age 14 (odds ratio=1.46 (1.12-1.92), p=0.006), after controlling for stimulant/hallucinogen use and level of education. CONCLUSIONS: Among patients experiencing a first episode of psychosis, CD symptoms were significantly associated with use of cannabis and with use by age 14. Among individuals vulnerable for psychosis, CD symptoms may independently increase the likelihood of cannabis use which in turn increases the risk of psychosis.