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Titolo:
Switching between the forest and the trees: Brain systems involved in local/global changed-level judgments
Autore:
Wilkinson, DT; Halligan, PW; Marshall, JC; Buchel, C; Dolan, RJ;
Indirizzi:
Univ Oxford, Dept Expt Psychol, Oxford OX1 3UD, England Univ Oxford Oxford England OX1 3UD Expt Psychol, Oxford OX1 3UD, England Rivermead Rehabil Ctr, Oxford OX1 4XD, England Rivermead Rehabil Ctr Oxford England OX1 4XD tr, Oxford OX1 4XD, England Cardiff Univ, Sch Psychol, Cardiff CF10 3YG, S Glam, Wales Cardiff Univ Cardiff S Glam Wales CF10 3YG ardiff CF10 3YG, S Glam, Wales Univ Oxford, Radcliffe Infirm, Dept Clin Neurol, Oxford OX2 6HE, England Univ Oxford Oxford England OX2 6HE Clin Neurol, Oxford OX2 6HE, England Inst Neurol, Wellcome Dept Cognit Neurol, London WC1N 3BG, England Inst Neurol London England WC1N 3BG nit Neurol, London WC1N 3BG, England Royal Free Hosp, Sch Med, London NW3 2DF, England Royal Free Hosp LondonEngland NW3 2DF Sch Med, London NW3 2DF, England
Titolo Testata:
NEUROIMAGE
fascicolo: 1, volume: 13, anno: 2001,
pagine: 56 - 67
SICI:
1053-8119(200101)13:1<56:SBTFAT>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
HIERARCHICAL STRUCTURE; SPATIAL-FREQUENCY; NEURAL MECHANISMS; GLOBAL FEATURES; ATTENTION; STIMULI; CONJUNCTION; MOVEMENT; FORMS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Wilkinson, DT Univ Oxford, Dept Expt Psychol, S Parks Rd, Oxford OX1 3UD, England Univ Oxford S Parks Rd Oxford England OX1 3UD 3UD, England
Citazione:
D.T. Wilkinson et al., "Switching between the forest and the trees: Brain systems involved in local/global changed-level judgments", NEUROIMAGE, 13(1), 2001, pp. 56-67

Abstract

Visual targets can be coded, in relative terms, at either the local or theglobal level of stimuli. Previous studies have indicated that targets are identified more slowly when they appear at a new hierarchical level, compared to when they reappear at the same level as in the previous trial. In thepresent study, we used measures of reaction time and event-related fMRI toinvestigate factors affecting this switch cost. In particular, we examinedthe effects of the number of repeated-level trials preceding a switch and whether the cue to switch was either externally or internally mediated. At the behavioral level we found that (1) the time taken to identify a target on a changed-level trial is longer following four repeated-level trials compared to two repeated-level trials, but that runs of six do not produce additional costs over four, and (2) targets can be identified faster followingexternally cued switches compared to internally mediated switches. Ne thenshow that these behavioral effects are associated with distinct patterns of neural activation. Switches performed after two repeated-level trials preferentially activated the precuneus, while those performed after bath four and six activated bilateral inferior parietal cortex and motor hand area. Relative to external switches, internal snitches activated the putamen, while both kinds of switch conjointly activated the large-scale network proposed to underlie internal/external switches in nonhierarchical tasks. Our datafurther clarify the mechanisms mediating hierarchical selection. (C) 2001 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/01/20 alle ore 13:05:51