Multi-item memory in the primate prefrontal cortex

The ability to retain multiple items in short-term memory is fundamental for cognition, yet almost nothing is known about its neural basis. To explore the mechanisms underlying this ability, we trained two monkeys to remember a sequence of two images across a short delay. We then recorded the activity of neurons from the lateral prefrontal cortex during task performance. We found that the majority of neurons showed delay activity that depended on the identity of both images (a minority reflected just one image), and that activity related to a given combination of images was only partially predictable from each neuron's activity to individual images. A model to predict the resultant neural activity was tested. We also examined the effect of task demands on the neural representation of multiple images. Our first experiment showed that each of the two images in memory was represented with a certain strength, and that this strength was dependent on how long the image had been in memory; image strength decayed as time progressed.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Brain and Cognitive Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Warden, Melissa R. (Melissa Rhoads)

Advisor dc:contributor.advisor

• Earl K. Miller.

• Brain and Cognitive Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/35910

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35910