281 research outputs found

    Sex and menstrual cycle influence human spatial navigation strategies and performance

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    Abstract 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‚ÄČ+‚ÄČML 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

    From cognitive maps to spatial schemas

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    A schema refers to a structured body of prior knowledge that captures common patterns across related experiences. Schemas have been studied separately in the realms of episodic memory and spatial navigation across different species and have been grounded in theories of memory consolidation, but there has been little attempt to integrate our understanding across domains, particularly in humans. We propose that experiences during navigation with many similarly structured environments give rise to the formation of spatial schemas (for example, the expected layout of modern cities) that share properties with but are distinct from cognitive maps (for example, the memory of a modern city) and event schemas (such as expected events in a modern city) at both cognitive and neural levels. We describe earlier theoretical frameworks and empirical findings relevant to spatial schemas, along with more targeted investigations of spatial schemas in human and non-human animals. Consideration of architecture and urban analytics, including the influence of scale and regionalization, on different properties of spatial schemas may provide a powerful approach to advance our understanding of spatial schemas

    The effects of imagery rescripting on memory outcomes in social anxiety disorder

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    The final publication is available at Elsevier via https://doi.org/10.1016/j.janxdis.2019.102152. © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Imagery rescripting (IR) is an effective intervention for social anxiety disorder (SAD) that targets negative autobiographical memories. IR has been theorized to work through various memory mechanisms, including modifying the content of negative memory representations, changing memory appraisals, and improving negative schema or core beliefs about self and others. However, no prior studies have investigated the unique effects of rescripting itself relative to other IR intervention components on these proposed mechanisms. In this preliminary study, 33 individuals with SAD were randomized to receive a single session of IR, imaginal exposure (IE), or supportive counselling (SC). Memory outcomes were assessed at 1- and 2-weeks post-intervention and at 3-months follow-up. Results demonstrated that the content of participants’ autobiographical memory representations changed in distinct ways across the three conditions. Whereas IR facilitated increases only in positive/neutral memory details, IE facilitated increases in both positive/neutral and negative memory details and SC facilitated no changes in memory details. Although memory appraisals did not differ across conditions, participants who received IR were more likely to update their negative memory-derived core beliefs. These unique effects of rescripting on memory representations and core beliefs enhance our understanding of the memory-based mechanisms of IR within the context of exposure-based learning for people with SAD.This work was supported by the Canadian Institutes of Health Research [grant numbers PJT-364337 to DM and MOP-49566 to MM]

    PROCESSING LEXICAL AMBIGUITY AND VISUAL WORD RECOGNITION IN A DEEP ORTHOGRAPHY*

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    This study examined the influence of phonemic and semantic ambiguity on lexical decision and naming performance in Hebrew. Most lexical ambiguity research has concentrated primarily on the way homographs (polysemous words) are disambiguated within a semantic context (for a recent review see Examination of lexical ambiguity in relation to lexical access and models of word recognition IS of special interest in Hebrew orthography because of its special way of conveying phonemic * Memory £4 Cognition, 1987, 15, 13-23. t Also

    Research Article IN SEARCH OF THE SELF: A Positron Emission Tomography Study

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    Abstract-Previous work using positron emission tomography (PET) has shown that memory encoding processes are associated with preferential activation of left frontal regions of the brain, whereas retrieval processes are associated predominantly with right frontal activations. One possible reason for the asymmetry is that episodic retrieval necessarily involves reference to the self, and the self-concept may be represented (at least partially) in right frontal regions. Accordingly, the present study investigated the possibility that encoding of self-related material might also activate right frontal areas. Eight right-handed volunteers judged trait adjectives under four separate PET scan conditions: (a) relevance to self, (b) relevance to a well-known public figure, (c) social desirability, and (d) number of syllables. The results showed that self-related encoding yielded left frontal activations similar to those associated with other types of semantic encoding, but also specific activations in the right frontal lobe. It is concluded that the concept of self involves both general schematic structures and further specific components involved in episodic memory retrieval. It is well established that encoding and retrieval processes in episodic memory involve different regions in the frontal lobes of the cerebral cortex. Specifically, encoding processes differentially engage left prefrontal areas, whereas retrieval processes for the same materials predominantly involve right prefrontal areas. This observed difference was embodied in the hemispheric encoding/retrieval asymmetry model (HERA; Tulving, One question that can be asked is whether these asymmetrical cortical activations reflect the processes of memory encoding and retrieval as such, or whether they reflect the involvement of necessary constituents of encoding and retrieval, respectively. It is known, for example, that effective encoding processes typically involve deep, elaborate, semantic-processing operations What are the necessary constituents of memory retrieval? James (1890, Vol. I, p. 650) made the point that for a mental event to be experienced as a personal memory, the imagined event must, first, be referred to the past and, second, be associated with feelings of self; that is, it must be dated in the rememberer's own personal past. Recent work involving positron emission tomography (PET) has shown that the retrieval of episodic memories is associated with activation of the prefrontal cortex, predominantly on the right (for reviews, see One major purpose of the present study was to examine the possibility that the association of episodic memory retrieval with activation of the right prefrontal cortex is attributable (in part at least) to the representation of self in this area of the brain. This conjecture receives some support from studies of brain-damaged patients with disturbances of self-awareness; such disorders are often associated with lesions of the right frontal cortex A related purpose of the study was to gather evidence on the neural correlates of self-referential processing. It has been shown that words processed with reference to the self are very well remembered, usually even better than words processed in general semantic terms schematic cognitive structure, and that new information learned with reference to self is encoded in a rich and distinctive manner. Furthermore, the organized, interdependent nature of the self-schema facilitates the formation of organizational links among the events to be remembered Participants in the PET scanner made judgments about lists of personality trait adjectives. Four types of judgments were made (only one type during any one scan); in all cases, participants rated each word on a 4-point scale by pressing one of four response keys. The four types of judgments were (a) self ("How well does the adjective describe you?"), (b) other ("How well does the adjective describe Brian Mulroney?"-a former Canadian prime minister), (c) general ("How socially desirable is the trait described by the adjective?"), and (d) syllable ("How many syllables does the adjective contain?"). Processing words in terms of the number of syllables reflects a relatively shallow type of verbal processing with little involvement of meaning; activations from these scans formed the baseline for PET measurements. The other condition was included to see whether personal judgments not related to self would be associated with activations different from those associated with selfreferential and general semantic encoding. Behavioral studies have shown that subsequent memory for words judged with reference to another person depends on how well known the target person is to the participant. When the other in question is well known (e.g., parent, best friend), subsequent memory levels are almost as high as those associated with self judgments METHOD Participants Eight right-handed volunteers (4 men and 4 women) were recruited for participation in the present investigation. The volunteers were between the ages of 19 and 26 years (M = 22.8), and had a mean education of 15.5 years. All participants were screened for a history or current evidence of any serious medical, neurological, or psychological disorder; they were also screened for recreational drug abuse. Informed consent was obtained from all volunteers before they participated, and they received a $50 reimbursement for their participation. The study was approved by the local ethics committee of the University of Toronto. Task Design Relative regional cerebral blood flow (rCBF) was measured while participants performed one of four encoding tasks; each task was performed twice, for a total of eight relative rCBF measurements (i.e., scans). The four tasks were presented in an ABCDDCBA design (counterbalanced across participants) to minimize order effects. Each task involved making judgments about personality trait adjectives on a 4-point scale. Sixteen similar lists of 32 personality trait adjectives were constructed using the personality trait adjectives found in In one task, representing encoding of self-referential information (self task), participants were requested to judge how well they thought each trait adjective described them. To indicate their judgment, they were instructed to press one of the four keys on the keypad beneath their right fingers. More specifically, they were requested to press the key beneath their index, middle, ring, or little finger if they thought that the trait adjective almost never, rarely, sometimes, or almost always described them, respectively. In a second task, representing encoding of information about another person (other task), participants were requested to judge how well they thought each trait adjective described Brian Mulroney by responding in the same way as in the self task. In a third task, representing encoding of semantic information not specific to a person (general task), participants were requested to judge how socially desirable the trait described by each adjective was. They judged each trait as being almost never, rarely, sometimes, or almost always socially desirable by pressing designated keys. In a fourth task, representing the encoding of nonsemantic information (syllable task), participants were requested to judge the number of syllables in each trait adjective. They pressed one of four keys depending on whether the adjective had two, three, four, or five syllables. Each trial consisted of a 500-ms fixation point followed by an adjective with a maximum duration of 2,000 ms. If the participant made his or her judgment within the 2,000 ms, then the screen wen

    Cognitive mapping style relates to posterior-anterior hippocampal volume ratio

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    As London taxi drivers acquire ‚Äėthe knowledge‚Äô and develop a detailed cognitive map of London, their posterior hippocampi (pHPC) gradually increase in volume, reflecting an increasing pHPC/aHPC volume ratio. In the mnemonic domain, greater pHPC/aHPC volume ratios in young adults have been found to relate to better recollection ability, indicating that the balance between pHPC and aHPC volumes might be reflective of cross-domain individual differences. Here, we examined participants‚Äô self-reported use of cognitive map-based navigational strategies in relation to their pHPC/aHPC hippocampal volume ratio. We find that greater reported cognitive map use was related to significantly greater posterior, relative to anterior, hippocampal volume in two separate samples of young adults. Further, greater reported cognitive map usage correlated with better performance on a self-initiated navigation task. Together, these data help to advance our understanding of differences between aHPC and pHPC and the greater role of pHPC in spatial mapping

    From Knowing to Remembering: the Semantic-Episodic distinction

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    The distinction between episodic and semantic memory was proposed in 1972 by Endel Tulving and is still of central importance in Cognitive Neuroscience today. Data obtained in the last 30 years or so, however, support the idea that the frontiers between perception and knowledge and between episodic and semantic memory are not as clear cut as previously thought, prompting a rethinking of the episodic-semantic distinction. Here, we review recent research on episodic and semantic memory, highlighting similarities between the two systems. Taken together, current behavioral, neuropsychological and neuroimaging data are compatible with the idea that episodic and semantic memory are inextricably intertwined, yet retain a measure of distinctiveness, despite the fact that their neural correlates demonstrate considerable overlap

    Differential activation of the medial temporal lobe during item and associative memory across time

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    Studies have shown that the hippocampus plays a crucial role in associative memory. One central issue is whether the involvement of the hippocampus in associative memory remains stable or declines with the passage of time. In the majority of studies, memory performance declines with delay, confounding attempts at interpreting differences in hippocampal activation over time. To address this issue, we tried to equate behavioral performance as much as possible across time for memory of items and associations separately. After encoding words and word pairs, participants were tested for item and associative memories at four time intervals: 20-min, 1-day, 1-week, and 1-month. The results revealed that MTL activation differed over time for associative and item memories. For associative memory, the activation of the anterior hippocampus decreased from 20-min to 1-day then remained stable, whereas in the posterior hippocampus, the activation was comparable for different time intervals when old pairs were correctly retrieved. The hippocampal activation also remained stable when recombined pairs were correctly rejected. As this condition controls for familiarity of the individual items, correct performance depends only on associative memory. For item memory, hippocampal activation declined progressively from 20-min to 1-week and remained stable afterwards. By contrast, the activation in the perirhinal/entorhinal cortex increased over time irrespective of item and associative memories. Drawing on Tulving's distinction between recollection and familiarity, we interpret this pattern of results in accordance with Trace Transformation Theory, which states that as memories are transformed with time and experience, the neural structures mediating item and associative memories will vary according to the underlying representations to which the memories have been transformed
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