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Rappresentazioni spaziali, orientamento e navigazione: studi funzionali e comportamentali ed una proposta neuro-funzionale
Full text linkDoes aging affect the formation of new topographical memories? Evidence from an extensive spatial training
No full textA decline in navigational abilities is a consistent feature of aging. Although many studies focused on recall of navigational informa- tion, the impact of time and type of learning on recall has received little attention. We submitted older adults and young participants to an extensive training of an ecological environment, from both route and survey perspectives. Then, we tested participants’ learn- ing using from both route and survey perspectives. Although older adults benefit from the extensive training, they did not reach the same performance of the young participants. Despite this main effect of age, the effect of the type of learning was the same in the two groups. Congruence between type of learning and recall led to better performance in both groups. We discuss these findings in the light of cognitive models of human navigation and aging. Useful suggestions about how these findings may inform a specific cognitive intervention in older adults are also provided
Cognitive maps in imagery neglect
No full textPatients with imagery neglect (RI+) show peculiar difficulties in orienting themselves in the environment. Navigational impairments could be due to a deficit in creating or using a mental representation of the environment (Guariglia, Piccardi, Iaria, Nico, & Pizzamiglio, 2005) or, according to the BBB model (Burgess, Becker, King, & O'Keefe, 2001), to a specific deficit in a mechanism that transforms an allocentric representation into an egocentric one and vice versa. Previous studies, however, do not allow discerning between a deficit in forming or in using a cognitive map, taking no notice of the fact that these are two different abilities underlain by different neuroanatomical areas, which could be independently impaired. Furthermore, the BBB model has never been verified in a population of brain-damaged patients. Therefore, we administered two tasks that separately assess the ability to create and use a cognitive map of the environment to 28 right brain-damaged patients (4 patients with imagery neglect and 4 patients with perceptual neglect) and 11 healthy participants. RI+ patients showed no specific deficit in creating or using a cognitive map, but failed to transform an egocentric representation of the environment into an allocentric one and vice versa, as predicted by the BBB model. (C) 2012 Elsevier Ltd. All rights reserved.Patients with imagery neglect (RI+) show peculiar difficulties in orienting themselves in the environ- ment. Navigational impairments could be due to a deficit in creating or using a mental representation of the environment (Guariglia, Piccardi, Iaria, Nico, & Pizzamiglio, 2005) or, according to the BBB model (Burgess, Becker, King, & O’Keefe, 2001), to a specific deficit in a mechanism that transforms an allocentric representation into an egocentric one and vice versa.
Previous studies, however, do not allow discerning between a deficit in forming or in using a cognitive map, taking no notice of the fact that these are two different abilities underlain by different neuroanatom- ical areas, which could be independently impaired. Furthermore, the BBB model has never been verified in a population of brain-damaged patients.
Therefore, we administered two tasks that separately assess the ability to create and use a cognitive map of the environment to 28 right brain-damaged patients (4 pat
Navigating toward a novel environment from a route or survey perspective. neural correlates and context dependent connectivity
No full textWhen we move toward a novel environment we may learn it in different ways, i.e., by walking around or studying a map. Both types of learning seem to be very effective in daily life navigation and correspond to two different types of mental representation of space: route and survey representation. In the present study, we investigated the neural basis of route and survey perspectives during learning and retrieval of novel environments. The study was carried out over 5 days, during which participants learned two paths from a different perspective (i.e., route learning and survey learning). Then participants had to retrieve these paths using a survey or route perspective during fMRI scans, on the first and fifth day. We found that the left inferior temporal lobe and right angular gyrus (AG) were activated more during recall of paths learned in a survey perspective than in a route perspective. We also found a session by perspective interaction effect on neural activity in brain areas classically involved in navigation such as the parahippocampal place area (PPA) and the retrosplenial cortex (RSC). A set of frontal, parietal and temporal areas showed different patterns of activity according to the type of retrieval perspective. We tested the context-dependent connectivity of right PPA, RSC and AG, finding that these areas showed different patterns of connectivity in relation to the learning and recalling perspective. Our results shed more light on the segregation of neural circuits involved in the acquisition of a novel environment and navigational strategies
Direct and indirect parieto-medial temporal pathways for spatial navigation in humans. evidence from resting-state functional connectivity
No full textAnatomical and functional findings in primates suggest the existence of a dedicated parieto-medial temporal pathway for spatial navigation, consisting of both direct and indirect projections from the caudal inferior parietal lobe (cIPL) to the hippocampus and the parahippocampal cortex, with indirect projections relaying through the posterior cingulate and retrosplenial cortex. This neural network is largely unexplored in humans. This study aimed at testing the existence of a parieto-medial temporal pathway for spatial navigation in humans. We explored the cortical connectivity patterns of the parahippocampal place area (PPA), the retrosplenial cortex (RSC), and the hippocampus (HC) using resting-state functional connectivity MRI. Our results demonstrate the existence of connections between the medial temporal lobe structures, i.e., PPA and HC, and the angular gyrus (AG), the human homologue of cIPL, as well as between RSC and AG. These connectivity patterns seem to reflect the direct and the indirect projections found in primates from cIPL to the medial temporal lobe. Such a result deserves feasible considerations to better understand the brain networks underpinning human spatial navigation
Segregation of neural circuits involved in spatial learning in reaching and navigational space
No full textRecent behavioral and neuropsychological studies suggest that visuo-spatial memory for reaching and navigational space is dissociated. In the present fMRI study, we investigated the hypothesis that learning spatial sequences in reaching and navigational space is processed by partially segregated neural systems. To this aim, we adapted the Corsi block tapping test (CBT) and the walking Corsi test (WalCT); the latter is a modification of the CBT in which subjects observe and reproduce spatial sequences by walking in a room instead of tapping wooden blocks on a table. Subjects were scanned while learning supra-span sequences of spatial locations through observation of video clips in which an actor tapped the blocks within reaching space (CBT) or walked on tiles placed on a carpet (WalCT). A large cerebral network spanning from visual occipital to parietal to frontal areas was activated dining learning of both the CBT and the WalCT sequences. Within this network right lingual gyrus, calcarine sulcus and dorsolateral prefrontal cortex were specifically associated with learning in navigational space, whereas left inferior temporal gyrus, lingual and fusiform gyrus and middle occipital gyrus were associated with learning sequences in reaching space. These results support the idea of a partial segregation between neural circuits for reaching and navigational space not only in the domain of perception and action planning but also in spatial learning and long-term memory. (C) 2013 Elsevier Ltd. All rights reserved.Recent behavioral and neuropsychological studies suggest that visuo-spatial memory for reaching and navigational space is dissociated. In the present fMRI study, we investigated the hypothesis that learning spatial sequences in reaching and navigational space is processed by partially segregated neural systems. To this aim, we adapted the Corsi Block Tapping Test (CBT) and the Walking Corsi Test (WalCT); the latter is a modification of the CBT in which subjects observe and reproduce spatial sequences by walking in a room instead of tapping wooden blocks on a table. Subjects were scanned while learning supra-span sequences of spatial locations through observation of video clips in which an actor tapped the blocks within reaching space (CBT) or walked on tiles placed on a carpet (WalCT). A large cerebral network spanning from visual occipital to parietal to frontal areas was activated during learning of both the CBT and the WalCT sequences. Within this network right lingual gyrus, calca
Where Am I? A new case of developmental topographical disorientation
No full textRecently, developmental topographical disorientation (DTD) was described (Bianchini etal., 2010, J Clin Exp Neuropsychol, 20, 807-27; Iaria & Barton, 2010, Exp Brain Res, 206, 189-96; Iaria, Bogod, Fox, & Barton, 2009, Neuropsychologia, 47, 30-40) as a navigational deficit in the absence of neurological or psychiatric disorders. Here, we reported the case of a healthy subject who presented this disorder. Dr. WAI was a 29-year-old right-handed man with normal development and no clinical history of neurological or psychiatric diseases who was affected by a very pervasive topographical orientation and navigational disorder. A neuroradiological exam confirmed the absence of structural and anatomical alterations of the brain. Dr. WAI was submitted to an extensive neuropsychological examination and to a battery of tests specifically developed to assess developmental topographical disorder. Using this battery, we analysed Dr. WAI's acquisition of navigational information and re-orientation processes. He showed severe DTD accompanied by deficits of different cognitive processes directly or indirectly involved in navigational skills. Dr. WAI showed a deficit in developing cognitive maps, already found in previous cases, plus difficulties in evaluating distances and computing metric environmental features. He represents a further confirmation of the existence of DTD suggesting dissociations within the disorder related to the level of development of the ability to build cognitive maps and the association of different imagery deficits. Dr. WAI can help in shedding some light on the mechanisms underlying lack of development of navigational skills
Neural Underpinnings of the Decline of Topographical Memory in Mild Cognitive Impairment
No full textSpatial navigation is one of the cognitive functions known to decline in both normal and pathological aging. In the present study, we aimed to assess the neural correlates of the decline of topographical memory in patients with amnestic mild cognitive impairment (aMCI). Patients with aMCI and age-matched controls were engaged in an intensive learning paradigm, lasting for 5 days, during which they had to encode 1 path from an egocentric perspective and 1 path from an allocentric perspective. After the learning period, they were asked to retrieve each of these paths using an allocentric or egocentric frame of reference while undergoing a functional magnetic resonance imaging scan. We found that patients with aMCI showed a specific deficit in storing new topographical memories from an allocentric perspective and retrieving stored information to perform the egocentric task. Imaging data suggest that this general decline is correlated with hypoactivation of the brain areas generally involved in spatial navigation
Action and non-action oriented body representations. insight from behavioural and grey matter modifications in individuals with lower limb amputation
Full text linkFollowing current model of body representations, we aimed to systematically investigate the association between brain modifications, in terms of grey matter loss, and body representation deficits, in terms of alterations of the body schema (BS) and of non-action oriented body representations (NA), in individuals with lower limb amputation (LLA)
Map-following skills in left and right brain-damaged patients with and without hemineglect
No full textMap-following tasks require a "semantic interpretation" of the map, which could be affected by left brain damage, and "superimposition of the map upon the space," which could be compromised by right lesions and particularly by the presence of hemineglect. Participants followed a pathway depicted on a map of a real environment. The pathway included four left and four right turns. A legend explained the meaning of each symbol that appeared on the map. Our results showed no deficits in left brain-damaged patients, but poor performance in right brain-damaged patients affected by hemineglect. This deficit can be ascribed to their impaired egocentric frame of reference, but we cannot exclude a prevalent role of the right hemisphere in their use of the allocentric information on the map despite the presence of hemineglect. Indeed, three right brain-damaged patients without hemineglect showed a specific deficit in performing the task. We discuss the results in light of the possible impairment of the parietomedial temporal pathway, which supports spatial navigation and could be responsible for the patients' deficit.Map-following tasks require a "semantic interpretation" of the map, which could be affected by left brain damage, and "superimposition of the map upon the space," which could be compromised by right lesions and particularly by the presence of hemineglect. Participants followed a pathway depicted on a map of a real environment. The pathway included four left and four right turns. A legend explained the meaning of each symbol that appeared on the map. Our results showed no deficits in left brain-damaged patients, but poor performance in right brain-damaged patients affected by hemineglect. This deficit can be ascribed to their impaired egocentric frame of reference, but we cannot exclude a prevalent role of the right hemisphere in their use of the allocentric information on the map despite the presence of hemineglect. Indeed, three right brain-damaged patients without hemineglect showed a specific deficit in performing the task. We discuss the results in light of the possible impairmen
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