Learned Representation of Implied Serial Order in Posterior Parietal Cortex.

摘要: Monkeys can learn the implied ranking of pairs images drawn from an ordered set, despite never seeing all simultaneously and without explicit spatial or temporal cues. We recorded activity posterior parietal cortex (including lateral intraparietal area LIP) neurons while monkeys learned 7-item transitive inference (TI) lists with 2 items presented on each trial. Behavior neuronal were significantly influenced by ordinal relationship stimulus pairs, specifically symbolic distance (the difference in rank) joint rank sum ranks). Symbolic strongly predicted decision accuracy learning rate. An effect performance was found nested within effect. Across population neurons, there significant modulation firing correlated relative ranks two stimuli Neurons exhibited selectivity for during learning, but not before after. The observed behavior is poorly explained associative reward mechanisms, appears more consistent a mental workspace model which serial order mapped framework. neural data suggest that supports representing information about given