PT  - JOURNAL ARTICLE
AU  - Barak, Omri
AU  - Tsodyks, Misha
AU  - Romo, Ranulfo
TI  - Neuronal Population Coding of Parametric Working Memory
AID  - 10.1523/JNEUROSCI.1875-10.2010
DP  - 2010 Jul 14
TA  - The Journal of Neuroscience
PG  - 9424--9430
VI  - 30
IP  - 28
4099  - http://www.jneurosci.org/content/30/28/9424.short
4100  - http://www.jneurosci.org/content/30/28/9424.full
SO  - J. Neurosci.2010 Jul 14; 30
AB  - Comparing two sequentially presented stimuli is a widely used experimental paradigm for studying working memory. The delay activity of many single neurons in the prefrontal cortex (PFC) of monkeys was found to be stimulus-specific, however, population dynamics of stimulus representation has not been elucidated. We analyzed the population state of a large number of PFC neurons during a somatosensory discrimination task. Using the tuning curves of the neurons, we derived a compact characterization of the population state. Stimulus representation by the population was found to degrade after stimulus termination, and emerge in a different form toward the end of the delay. Specifically, the tuning properties of neurons were found to change during the task. We suggest a mechanism whereby information about the stimulus is contained in activity-dependent synaptic facilitation of recurrent connections.