Differing viewpoint effects in the ventral and dorsal visual streams revealed using fMRI
Bibliographic record
Abstract
Neuroimaging studies using object stimuli have typically focused on activation produced in the ventral occipital and temporal cortices, which are part of the ventral stream of visual processing. Many of these studies, however, also report activation in a region of the posterior parietal cortex, a part of the dorsal stream, that is activated by object stimuli. We investigated the contribution of this parietal region to object viewing, by using a priming paradigm in combination with high-field fMRI. Subjects were repeatedly presented with images of common and novel objects. Some of the repeated images were identical to the initial presentation and some of the images were of the same objects, but rotated in depth. We found that area LO, part of the ventral stream, showed viewpoint invariance, responding the same way to identical and rotated images of objects presented earlier. This result corresponded to behavioural data that showed equivalent performance with identical and rotated images. Area cIPS, part of the dorsal stream, showed priming only with identical images, and appeared to treat rotated images as new objects. This difference in the pattern of priming-related activation in the two areas may reflect the respective roles of the ventral and dorsal streams in object recognition and object-directed action. This difference may also reflect the use of object-based versus observer-based frames of reference in the ventral and dorsal streams.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".