Linked Life Data

19146357

Source:http://linkedlifedata.com/resource/pubmed/id/19146357

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2009-1-16
pubmed:abstractText
Human psychophysical observations, computational models, and the selectivity of neurons in primary visual cortex all suggest that an early step in visual processing is the detection of features such as lines and edges. However, previous fMRI experiments investigating the responses of early visual areas to phase coherence have led to apparently discordant results. We studied the human brain BOLD responses to structured periodic band-pass images of matched amplitude spectrum but of different phase spectra, arranged to create three distinct types of stimuli: pure edges; pure lines (matched global and local energy to the edges, but different phase); and random noise (random phase spectrum, hence no salient features, and a different spatial distribution of local energy from the lines and edges stimuli). Alternation of lines against edges did not activate primary visual cortex, but did activate two higher order visual areas. Alternation of these lines or edges against the random stimulus produced a strong activity in many visual areas, including primary visual cortex. Interestingly, the BOLD activity was higher for the edges and lines than for the random stimuli for a wide range of stimulus contrasts, indicating the presence of non-linear gain modulation in the cell response. These results show that phase congruency is coded at the level of primary visual cortex. We show that a stage of response gain modulation can explain our present and previous fMRI discordant results.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1534-7362
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15.1-15
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
BOLD response to spatial phase congruency in human brain.
pubmed:affiliation
Scuola Normale Superiore, Istituto di Neuroscienze CNR, Pisa, Italy. perna@cict.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't