Sebastian M. Frank and Eric A. Reavis contributed equally to this work.
Neural mechanisms of feature conjunction learning: Enduring changes in occipital cortex after a week of training
Version of Record online: 18 FEB 2013
Copyright © 2013 Wiley Periodicals, Inc.
Human Brain Mapping
Volume 35, Issue 4, pages 1201–1211, April 2014
How to Cite
Frank, S. M., Reavis, E. A., Tse, P. U. and Greenlee, M. W. (2014), Neural mechanisms of feature conjunction learning: Enduring changes in occipital cortex after a week of training. Hum. Brain Mapp., 35: 1201–1211. doi: 10.1002/hbm.22245
- Issue online: 20 MAR 2014
- Version of Record online: 18 FEB 2013
- Manuscript Accepted: 26 NOV 2012
- Manuscript Revised: 25 OCT 2012
- Manuscript Received: 3 MAY 2012
- German Ministry of Education and Research (BMBF). Grant Number: 01GW0761—Brain plasticity and perceptual learning
- Alexander von Humboldt Foundation, EAR by the National Science Foundation Graduate Research Fellowship Program
- perceptual learning;
- visual cortex;
- visual search;
- neural plasticity
Most visual activities, whether reading, driving, or playing video games, require rapid detection and identification of learned patterns defined by arbitrary conjunctions of visual features. Initially, such detection is slow and inefficient, but it can become fast and efficient with training. To determine how the brain learns to process conjunctions of visual features efficiently, we trained participants over eight consecutive days to search for a target defined by an arbitrary conjunction of color and location among distractors with a different conjunction of the same features. During each training session, we measured brain activity with functional magnetic resonance imaging (fMRI). The speed of visual search for feature conjunctions improved dramatically within just a few days. These behavioral improvements were correlated with increased neural responses to the stimuli in visual cortex. This suggests that changes in neural processing in visual cortex contribute to the speeding up of visual feature conjunction search. We find evidence that this effect is driven by an increase in the signal-to-noise ratio (SNR) of the BOLD signal for search targets over distractors. In a control condition where target and distractor identities were exchanged after training, learned search efficiency was abolished, suggesting that the primary improvement was perceptual learning for the search stimuli, not task-learning. Moreover, when participants were retested on the original task after nine months without further training, the acquired changes in behavior and brain activity were still present, showing that this can be an enduring form of learning and neural reorganization. Hum Brain Mapp 35:1201–1211, 2014. © 2013 Wiley Periodicals, Inc.