Stereoscopic processing of absolute and relative disparity in human visual cortex

被引:139
作者
Neri, P
Bridge, H
Heeger, DJ
机构
[1] Stanford Univ, Dept Psychol, Stanford, CA 94305 USA
[2] Univ Oxford, Physiol Lab, Oxford OX1 3PT, England
关键词
D O I
10.1152/jn.01042.2003
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Stereoscopic vision relies mainly on relative depth differences between objects rather than on their absolute distance in depth from where the eyes fixate. However, relative disparities are computed from absolute disparities, and it is not known where these two stages are represented in the human brain. Using functional MRI ( fMRI), we assessed absolute and relative disparity selectivity with stereoscopic stimuli consisting of pairs of transparent planes in depth in which the absolute and relative disparity signals could be independently manipulated ( at a local spatial scale). In experiment 1, relative disparity was kept constant, while absolute disparity was varied in one-half the blocks of trials ("mixed" blocks) and kept constant in the remaining one-half ("same" blocks), alternating between blocks. Because neuronal responses undergo adaptation and reduce their firing rate following repeated presentation of an effective stimulus, the fMRI signal reflecting activity of units selective for absolute disparity is expected to be smaller during "same" blocks as compared with "mixed" ones. Experiment 2 similarly manipulated relative disparity rather than absolute disparity. The results from both experiments were consistent with adaptation with differential effects across visual areas such that 1) dorsal areas (V3A, MT+/V5, V7) showed more adaptation to absolute than to relative disparity; 2) ventral areas (hV4, V8/V4alpha) showed an equal adaptation to both; and 3) early visual areas (V1, V2, V3) showed a small effect in both experiments. These results indicate that processing in dorsal areas may rely mostly on information about absolute disparities, while ventral areas split neural resources between the two types of stereoscopic information so as to maintain an important representation of relative disparity.
引用
收藏
页码:1880 / 1891
页数:12
相关论文
共 97 条
[1]   Stereoscopic vision: What's the first step? [J].
Backus, BT .
CURRENT BIOLOGY, 2000, 10 (19) :R701-R703
[2]   Human cortical activity correlates with stereoscopic depth perception [J].
Backus, BT ;
Fleet, DJ ;
Parker, AJ ;
Heeger, DJ .
JOURNAL OF NEUROPHYSIOLOGY, 2001, 86 (04) :2054-2068
[3]   DEPTH-INCREMENT DETECTION FUNCTION FOR INDIVIDUAL SPATIAL CHANNELS [J].
BADCOCK, DR ;
SCHOR, CM .
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, 1985, 2 (07) :1211-1216
[4]   NEURAL MECHANISM OF BINOCULAR DEPTH DISCRIMINATION [J].
BARLOW, HB ;
BLAKEMOR.C ;
PETTIGRE.JD .
JOURNAL OF PHYSIOLOGY-LONDON, 1967, 193 (02) :327-&
[5]   RANGE AND SCOPE OF BINOCULAR DEPTH DISCRIMINATION IN MAN [J].
BLAKEMORE, C .
JOURNAL OF PHYSIOLOGY-LONDON, 1970, 211 (03) :599-+
[6]   SOME RECENT FINDINGS ON THE DEVELOPMENT OF HUMAN BINOCULARITY - A REVIEW [J].
BRADDICK, OJ ;
ATKINSON, J .
BEHAVIOURAL BRAIN RESEARCH, 1983, 10 (01) :141-150
[7]   A physiological correlate of the 'spotlight' of visual attention [J].
Brefczynski, JA ;
DeYoe, EA .
NATURE NEUROSCIENCE, 1999, 2 (04) :370-374
[8]  
BURKHALTER A, 1986, J NEUROSCI, V6, P2327
[9]   DISPARITY-TUNED CHANNELS OF THE HUMAN VISUAL-SYSTEM [J].
CORMACK, LK ;
STEVENSON, SB ;
SCHOR, CM .
VISUAL NEUROSCIENCE, 1993, 10 (04) :585-596
[10]   Stereopsis: Where depth is seen [J].
Cumming, B .
CURRENT BIOLOGY, 2002, 12 (03) :R93-R95