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Conscious processing during retrieval can occur in early and late visual regions
Preston P Thakral1, Scott D Slotnick, Daniel L Schacter
1Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX 75235, United States. preston6667@gmail.com
Neuropsychologia
|November 27, 2012
Summary
Conscious memory retrieval can involve early visual brain regions (BA17/18), challenging previous theories. This functional magnetic resonance imaging (fMRI) study demonstrates conscious processing in these areas during specific memory tasks.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Neuroimaging
Background:
- Prior research suggested a division in visual processing during memory retrieval, with early regions (BA17/18) linked to nonconscious and later regions (BA19/37) to conscious processing.
- This functional-anatomic dissociation was primarily based on limited experimental paradigms.
Purpose of the Study:
- To investigate whether conscious processing during memory retrieval can occur in early visual regions (BA17/18).
- To test this hypothesis using memorial paradigms specifically designed to engage these early visual areas.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed in two experiments.
- Participants encoded abstract shapes and later performed retrieval tasks involving classification of old/new items and spatial/item memory, under specific or non-specific retrieval orientations.
Main Results:
- Experiment 1: The contrast of spatial memory hits versus misses (with accurate item memory) revealed activity in BA17/18.
- Experiment 2: The contrast of old item hits versus misses during a specific retrieval orientation also showed activity in BA17/18.
Conclusions:
- The findings support the hypothesis that conscious processing during memory retrieval is not restricted to later visual regions.
- Conscious processing can indeed engage early visual cortical areas (BA17/18) under specific memorial retrieval conditions.
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