Open AccessCommon and dissociated mechanisms for estimating large and small dot arrays: Value‐specific fMRI adaptation
Author(s) -
Demeyere Nele,
Rotshtein Pia,
Humphreys Glyn W.
Publication year - 2014
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.22453
Subject(s) - numerosity adaptation effect , intraparietal sulcus , neuroscience , psychology , prefrontal cortex , posterior parietal cortex , parietal lobe , functional magnetic resonance imaging , sulcus , stimulus (psychology) , visual cortex , cognitive psychology , cognition
An fMRI pair‐adaptation paradigm was used to identify the brain regions linked to the apprehension of small and large numbers of items. Participants classified stimuli on the basis of their numerosities (fewer or more than five dots). We manipulated the type of repetition within pairs of dot arrays. Overall processing of pairs with small as opposed to large quantities was associated with a decreased BOLD response in the midline structures and inferior parietal cortex. The opposite pattern was observed in middle cingulate cortex. Pairs in which the same numerosity category was repeated, were associated with a decreased signal in the left prefrontal and the left inferior parietal cortices, compared with when numerosities changed. Repetitions of exact numerosities irrespective of sample size were associated with decreased responses in bi‐lateral prefrontal, sensory‐motor regions, posterior occipital and left intraparietal sulcus (IPS). More importantly, we found value‐specific adaptation specific to repeated small quantity in the left lateral occipito‐temporal cortex, irrespective of whether the exact same stimulus pattern repeated. Our results indicate that a large network of regions (including the IPS) support visual quantity processing independent of the number of items present; however assimilation of small quantities is associated with additional support from regions within the left occipito‐temporal cortex. We propose that processing of small quantities is aided by a subitizing‐specific network. This network may account for the increased processing efficiency often reported for numerosities in the subitizing range. Hum Brain Mapp 35:3988–4001, 2014 . © 2014 Wiley Periodicals, Inc .