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Neil Burgess - One of the best experts on this subject based on the ideXlab platform.
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Impaired allocentric Spatial Processing in posttraumatic stress disorder.
Neurobiology of learning and memory, 2015Co-Authors: Kirsten V. Smith, Neil Burgess, Chris R. Brewin, John A. KingAbstract:A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual Processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric Spatial Processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N=29) and without (N=30) a diagnosis of PTSD completed two tests of Spatial Processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects' locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric Spatial Processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-Spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse Spatial Processing in the PTSD group. Results show a selective impairment in allocentric Spatial Processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy.
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The hippocampus and memory: insights from Spatial Processing
Nature Reviews Neuroscience, 2008Co-Authors: Chris M. Bird, Neil BurgessAbstract:Bird and Burgess review the hippocampus's role in memory in light of a model of neuronal Processing in which hippocampal activity constrains neocortical information to be perceivable from a single location. This enables Spatially coherent mental imagery, explaining several recent findings and theoretical conflicts. Damage to the hippocampus in humans can cause profound impairments in long-term episodic memory, but the precise functional contribution of the hippocampus remains the subject of several competing theories. Electrophysiological studies in rodents have characterized the firing properties of 'place cells' in the hippocampus in great detail. Place cells appear to represent where an animal 'thinks' it is located in an environment, relative to environmental boundaries. Acting cooperatively, place cells encode specific environments, performing both pattern completion and pattern separation. A new model of hippocampal Processing that is driven by the properties of place cells (the BBB model) provides an alternative to existing psychological theories, at least in the Spatial domain. The BBB model proposes that the hippocampus is needed to impose a location from which to retrieve and construct a coherent mental image of an environment. This mental image supports the online maintenance and manipulation of representations of the locations of objects and features in an environment. The model suggests that episodic memory will always be hippocampus-dependent if it is associated with rich mental imagery of an environment. Other sophisticated long-term Spatial (and non-Spatial) representations can be acquired, stored and retrieved independent of the hippocampus. However, the hippocampus is often needed to mediate behaviours that allow such learning to take place (such as when learning a new route). The BBB model further suggests that the hippocampus is required for both short-term and long-term memory for some types of information, for imagining complex visual scenes (be they real or fictitious), and more for the recognition of scenes than faces. Recent experimental evidence from studies of the effects of damage to the hippocampus in humans supports all three of these proposals. Hippocampal Processing beyond the Spatial domain cannot be explained by the BBB model, but several theoretical positions have been advanced to address the broader role of the hippocampus in mnemonic Processing. The hippocampus appears to be crucial for long-term episodic memory, yet its precise role remains elusive. Electrophysiological studies in rodents offer a useful starting point for developing models of hippocampal Processing in the Spatial domain. Here we review one such model that points to an essential role for the hippocampus in the construction of mental images. We explain how this neural-level mechanistic account addresses some of the current controversies in the field, such as the role of the hippocampus in imagery and short-term memory, and discuss its broader implications for the neural bases of episodic memory.
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The hippocampus and memory: insights from Spatial Processing
Nature Reviews Neuroscience, 2008Co-Authors: Neil BurgessAbstract:The hippocampus appears to be crucial for long-term episodic memory, yet its precise role remains elusive. Electrophysiological studies in rodents offer a useful starting point for developing models of hippocampal Processing in the Spatial domain. Here we review one such model that points to an essential role for the hippocampus in the construction of mental images. We explain how this neural-level mechanistic account addresses some of the current controversies in the field, such as the role of the hippocampus in imagery and short-term memory, and discuss its broader implications for the neural bases of episodic memory.
Helen Glyde - One of the best experts on this subject based on the ideXlab platform.
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Remediation of Spatial Processing deficits in hearing-impaired children and adults.
Journal of the American Academy of Audiology, 2014Co-Authors: Helen Glyde, Sharon Cameron, Harvey Dillon, Louise HicksonAbstract:Background: The ability to use interaural cues to segregate target speech from competing signals allows people with normal hearing to understand speech at significantly poorer signal-to-noise ratio's. This ability, referred to as Spatial Processing ability or Spatial release from masking, has been shown to be deficient in people with a sensorineural hearing loss even after amplification is applied. Spatial Processing deficits in a population of children with auditory Processing deficits have been found to be remediable through the use of a deficit-specific auditory training program called the LiSN & Learn.
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The effects of hearing impairment and aging on Spatial Processing.
Ear and hearing, 2013Co-Authors: Helen Glyde, Sharon Cameron, Harvey Dillon, Louise Hickson, Mark SeetoAbstract:Objectives Difficulty in understanding speech in background noise is frequently reported by hearing-impaired people despite well-fitted amplification. Understanding speech in the presence of background noise involves segregating the various auditory stimuli into distinct streams using cues such as pitch characteristics, Spatial location of speakers, and contextual information. One possible cause of listening difficulties in noise is reduced Spatial-Processing ability. Previous attempts to investigate Spatial Processing in hearing-impaired people have often been confounded by inadequate stimulus audibility. The present research aimed to investigate the effects of hearing impairment and aging on Spatial-Processing ability. The effect of cognitive ability on Spatial Processing was also explored. In addition, the relationship between Spatial-Processing ability and self-report measures of listening difficulty was examined to investigate how much effect Spatial-Processing ability has in real-world situations. Design Eighty participants aged between 7 and 89 years took part in the study. Participants' hearing thresholds ranged from within normal limits to a moderately severe sensorineural hearing loss. All participants had English as their first language and no reported learning disabilities. The study sample included both hearing aid users and non-hearing aid users. Spatial-Processing ability was assessed with a modified version of the Listening in Spatialized Noise-Sentences test (LiSN-S). The LiSN-S was modified to incorporate a prescribed gain amplifier that amplified the target and distracting stimulus according to the National Acoustic Laboratories-Revised Profound (NAL-RP) prescription. In addition, participants aged 18 years and above completed the Neurobehavioral Cognitive Status examination and the Speech, Spatial and Qualities questionnaire. Participants aged under 18 years completed the Listening Inventory for Education questionnaire. Results Spatial-Processing ability, as measured by the Spatial advantage measure of the LiSN-S, was negatively affected by hearing impairment. Aging was not significantly correlated with Spatial-Processing ability. No significant relationship was found between cognitive ability and Spatial Processing. Self-reported listening difficulty in children, as measured with the Listening Inventory for Education, and Spatial-Processing ability were not correlated. Self-reported listening difficulty in adults, as measured by the Speech, Spatial and Qualities questionnaire, was significantly correlated with Spatial-Processing ability. Conclusions All hearing-impaired people will have a Spatial Processing deficit of some degree. This should be given due consideration when counseling patients in regard to realistic expectations of how they will perform in background noise. Further research is required into potential remediation for Spatial-Processing deficits and the cause of these deficits.
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problems hearing in noise in older adults a review of Spatial Processing disorder
Trends in Amplification, 2011Co-Authors: Helen Glyde, Sharon Cameron, Louise Hickson, Harvey DillonAbstract:Difficulty understanding speech in background noise, even with amplification to restore audibility, is a common problem for hearing-impaired individuals and is especially frequent in older adults. Despite the debilitating nature of the problem the cause is not yet completely clear. This review considers the role of Spatial Processing ability in understanding speech in noise, highlights the potential impact of disordered Spatial Processing, and attempts to establish if aging leads to reduced Spatial Processing ability. Evidence supporting and opposing the hypothesis that Spatial Processing is disordered among the aging population is presented. With a few notable exceptions, Spatial Processing ability was shown to be reduced in an older population in comparison to young adults, leading to poorer speech understanding in noise. However, it is argued that to conclude aging negatively effects Spatial Processing ability may be oversimplified or even premature given potentially confounding factors such as cognitive ability and hearing impairment. Further research is required to determine the effect of aging and hearing impairment on Spatial Processing and to investigate possible remediation options for Spatial Processing disorder.
Michael E. Goldberg - One of the best experts on this subject based on the ideXlab platform.
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Spatial Processing in the monkey frontal eye field ii memory responses
Journal of Neurophysiology, 2001Co-Authors: Marc M. Umeno, Michael E. GoldbergAbstract:Monkeys and humans can easily make accurate saccades to stimuli that appear and disappear before an intervening saccade to a different location. We used the flashed-stimulus task to study the memor...
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Spatial Processing in the Monkey Frontal Eye Field. I. Predictive Visual Responses
Journal of neurophysiology, 1997Co-Authors: Marc M. Umeno, Michael E. GoldbergAbstract:Umeno, M. M. and Goldberg, M. E. Spatial Processing in the monkey frontal eye field. I. Predictive visual responses. J. Neurophysiol. 78: 1373–1383, 1997. Neurons in the lateral intraparietal area ...
Harvey Dillon - One of the best experts on this subject based on the ideXlab platform.
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Remediation of Spatial Processing deficits in hearing-impaired children and adults.
Journal of the American Academy of Audiology, 2014Co-Authors: Helen Glyde, Sharon Cameron, Harvey Dillon, Louise HicksonAbstract:Background: The ability to use interaural cues to segregate target speech from competing signals allows people with normal hearing to understand speech at significantly poorer signal-to-noise ratio's. This ability, referred to as Spatial Processing ability or Spatial release from masking, has been shown to be deficient in people with a sensorineural hearing loss even after amplification is applied. Spatial Processing deficits in a population of children with auditory Processing deficits have been found to be remediable through the use of a deficit-specific auditory training program called the LiSN & Learn.
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The effects of hearing impairment and aging on Spatial Processing.
Ear and hearing, 2013Co-Authors: Helen Glyde, Sharon Cameron, Harvey Dillon, Louise Hickson, Mark SeetoAbstract:Objectives Difficulty in understanding speech in background noise is frequently reported by hearing-impaired people despite well-fitted amplification. Understanding speech in the presence of background noise involves segregating the various auditory stimuli into distinct streams using cues such as pitch characteristics, Spatial location of speakers, and contextual information. One possible cause of listening difficulties in noise is reduced Spatial-Processing ability. Previous attempts to investigate Spatial Processing in hearing-impaired people have often been confounded by inadequate stimulus audibility. The present research aimed to investigate the effects of hearing impairment and aging on Spatial-Processing ability. The effect of cognitive ability on Spatial Processing was also explored. In addition, the relationship between Spatial-Processing ability and self-report measures of listening difficulty was examined to investigate how much effect Spatial-Processing ability has in real-world situations. Design Eighty participants aged between 7 and 89 years took part in the study. Participants' hearing thresholds ranged from within normal limits to a moderately severe sensorineural hearing loss. All participants had English as their first language and no reported learning disabilities. The study sample included both hearing aid users and non-hearing aid users. Spatial-Processing ability was assessed with a modified version of the Listening in Spatialized Noise-Sentences test (LiSN-S). The LiSN-S was modified to incorporate a prescribed gain amplifier that amplified the target and distracting stimulus according to the National Acoustic Laboratories-Revised Profound (NAL-RP) prescription. In addition, participants aged 18 years and above completed the Neurobehavioral Cognitive Status examination and the Speech, Spatial and Qualities questionnaire. Participants aged under 18 years completed the Listening Inventory for Education questionnaire. Results Spatial-Processing ability, as measured by the Spatial advantage measure of the LiSN-S, was negatively affected by hearing impairment. Aging was not significantly correlated with Spatial-Processing ability. No significant relationship was found between cognitive ability and Spatial Processing. Self-reported listening difficulty in children, as measured with the Listening Inventory for Education, and Spatial-Processing ability were not correlated. Self-reported listening difficulty in adults, as measured by the Speech, Spatial and Qualities questionnaire, was significantly correlated with Spatial-Processing ability. Conclusions All hearing-impaired people will have a Spatial Processing deficit of some degree. This should be given due consideration when counseling patients in regard to realistic expectations of how they will perform in background noise. Further research is required into potential remediation for Spatial-Processing deficits and the cause of these deficits.
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problems hearing in noise in older adults a review of Spatial Processing disorder
Trends in Amplification, 2011Co-Authors: Helen Glyde, Sharon Cameron, Louise Hickson, Harvey DillonAbstract:Difficulty understanding speech in background noise, even with amplification to restore audibility, is a common problem for hearing-impaired individuals and is especially frequent in older adults. Despite the debilitating nature of the problem the cause is not yet completely clear. This review considers the role of Spatial Processing ability in understanding speech in noise, highlights the potential impact of disordered Spatial Processing, and attempts to establish if aging leads to reduced Spatial Processing ability. Evidence supporting and opposing the hypothesis that Spatial Processing is disordered among the aging population is presented. With a few notable exceptions, Spatial Processing ability was shown to be reduced in an older population in comparison to young adults, leading to poorer speech understanding in noise. However, it is argued that to conclude aging negatively effects Spatial Processing ability may be oversimplified or even premature given potentially confounding factors such as cognitive ability and hearing impairment. Further research is required to determine the effect of aging and hearing impairment on Spatial Processing and to investigate possible remediation options for Spatial Processing disorder.
Franco Lepore - One of the best experts on this subject based on the ideXlab platform.
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Relevance of Spectral Cues for Auditory Spatial Processing in the Occipital Cortex of the Blind
Frontiers in psychology, 2011Co-Authors: Patrice Voss, Franco Lepore, Frédéric Gougoux, Robert J. ZatorreAbstract:We have previously shown that some blind individuals can localize sounds more accurately than their sighted counterparts when one ear is obstructed, and that this ability is strongly associated with occipital cortex activity. Given that spectral cues are important for monaurally localizing sounds when one ear is obstructed, and that blind individuals are more sensitive to small spectral differences, we hypothesized that enhanced use of spectral cues via occipital cortex mechanisms could explain the better performance of blind individuals in monaural localization. Using positron-emission tomography (PET), we scanned blind and sighted persons as they discriminated between sounds originating from a single Spatial position, but with different spectral profiles that simulated different Spatial positions based on head-related transfer functions. We show here that a sub-group of early blind individuals showing superior monaural sound localization abilities performed significantly better than any other group on this spectral discrimination task. For all groups, performance was best for stimuli simulating peripheral positions, consistent with the notion that spectral cues are more helpful for discriminating peripheral sources. PET results showed that all blind groups showed cerebral blood flow increases in the occipital cortex; but this was also the case in the sighted group. A voxel-wise covariation analysis showed that more occipital recruitment was associated with better performance across all blind subjects but not the sighted. An inter-regional covariation analysis showed that the occipital activity in the blind covaried with that of several frontal and parietal regions known for their role in auditory Spatial Processing. Overall, these results support the notion that the superior ability of a sub-group of early-blind individuals to localize sounds is mediated by their superior ability to use spectral cues, and that this ability is subserved by cortical Processing in the occipital cortex.
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functional specialization for auditory Spatial Processing in the occipital cortex of congenitally blind humans
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Olivier Collignon, Patrice Voss, Maryse Lassonde, Gilles Vandewalle, Genevieve Albouy, Genevieve Charbonneau, Franco LeporeAbstract:The study of the congenitally blind (CB) represents a unique opportunity to explore experience-dependant plasticity in a sensory region deprived of its natural inputs since birth. Although several studies have shown occipital regions of CB to be involved in nonvisual Processing, whether the functional organization of the visual cortex observed in sighted individuals (SI) is maintained in the rewired occipital regions of the blind has only been recently investigated. In the present functional MRI study, we compared the brain activity of CB and SI Processing either the Spatial or the pitch properties of sounds carrying information in both domains (i.e., the same sounds were used in both tasks), using an adaptive procedure specifically designed to adjust for performance level. In addition to showing a substantial recruitment of the occipital cortex for sound Processing in CB, we also demonstrate that auditory–Spatial Processing mainly recruits the right cuneus and the right middle occipital gyrus, two regions of the dorsal occipital stream known to be involved in visuoSpatial/motion Processing in SI. Moreover, functional connectivity analyses revealed that these reorganized occipital regions are part of an extensive brain network including regions known to underlie audiovisual Spatial abilities (i.e., intraparietal sulcus, superior frontal gyrus). We conclude that some regions of the right dorsal occipital stream do not require visual experience to develop a specialization for the Processing of Spatial information and to be functionally integrated in a preexisting brain network dedicated to this ability.
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Cross-modal plasticity for the Spatial Processing of sounds in visually deprived subjects
Experimental Brain Research, 2008Co-Authors: Olivier Collignon, Patrice Voss, Maryse Lassonde, Franco LeporeAbstract:Until only a few decades ago, researchers still considered sensory cortices to be fixed or “hardwired,” with specific cortical regions solely dedicated to the Processing of selective sensory inputs. But recent evidences have shown that the brain can rewire itself, showing an impressive range of cross-modal plasticity. Visual deprivation is one of the rare human models that allow us to explore the role of experience-dependent plasticity of a sensory cortex deprived of its natural inputs. The objective of this paper is to describe recent results regarding the Spatial Processing of sounds in blind subjects. These studies suggest that blind individuals may demonstrate exceptional abilities in auditory Spatial Processing and that such enhanced performances may be intrinsically linked to the recruitment of occipital areas deprived of their normal visual inputs. Such results highlight the brain’s remarkable ability to rewire its components to compensate for the challenging neurological condition that is visual deprivation. Moreover, we shall discuss that such cross-modal recruitment may, to some extent, follow organizational principles similar to the functional topography of the region observed in the sighted. Even if such recruitment is especially present in individuals having lost their sight in early infancy, occipital regions also show impressive plastic properties when vision is lost at a later age. This observation will be related to recent results demonstrating that occipital regions play a more important role than previously expected in the Spatial Processing of sounds, even in sighted subjects. Putative physiological mechanisms underlying such cross-modal recruitment will then be discussed. All these results have important implications for understanding the role of visual experience in shaping the development of occipital regions and may guide the implementation of rehabilitative methods such as sensory substitution or neural implants.
