Massachusetts Institute of Technology
Sign in | Create Account

Philip Sharp Lecture in Neural Circuits: Dr. Okihide Hikosaka

"Choosing good objects – a basal ganglia mechanism"

Speaker:  Okihide Hikosaka
Affiliation: Laboratory of Sensorimotor Research, National Eye Institute, NIH
Date: Thursday, March 1

Abstract:
Many objects around us have values which have been acquired through our life-long history. This suggests that the values of individual objects are stored in the brain as long-term memories. Our recent experiments suggest that such object-value memories are represented in part of the basal ganglia including the tail of the caudate nucleus (CDt) and the substantia nigra pars reticulata (SNr). We had monkeys look at many visual objects repeatedly in association with different but consistent reward values: half of the objects associated with a large reward (good objects) and the other half associated with a small reward (bad objects). Initially there was little effect of the object-reward association learning. However, after learning sessions across several days, CDt and SNr neurons started showing differential responses to the good and bad objects. In the end, SNr neurons reliably classified surprisingly many visual objects (nearly 300 in each monkey, so far tested) into good and bad objects. This neuronal bias remained intact even after >100 days of no training, even though the monkey continued to learn many other objects. The object value signals in the CDt and SNr are likely used for controlling saccadic eye movements, because many of the SNr neurons projected to the superior colliculus and electrical stimulation in the CDt induced saccades. Our results suggest that choosing good objects among many depends on the basal ganglia-mediated long-term memories. This basal ganglia mechanism may play an underlying role in visuomotor and cognitive skills.

Comments (0)

It looks like no one has posted a comment yet. You can be the first!

You need to log in, in order to post comments. If you don’t have an account yet, sign up now!

McGovern Institute for Brain Research

McGovern Institute for Brain Research

Category: Research | Updated 8 months ago

Created
March 05, 2012 17:49
Category
License
All Rights Reserved (What is this?)
Additional Files


Viewed
2473 times

More from McGovern Institute for Brain Research

Understanding the brain basis of autism

Understanding the brain basis of au...

Added 4 years ago | 00:04:35 | 8673 views

A View of the Brain

A View of the Brain

Added over 4 years ago | 00:00:19 | 6064 views

Alan Alda: The Art of Science Communication

Alan Alda: The Art of Science Commu...

Added 4 years ago | 00:00:00 | 24293 views

McGovern 2013 Fall Symposium - Jisong Guan

McGovern 2013 Fall Symposium - Jiso...

Added 12 months ago | 00:32:20 | 254 views

McGovern 2013 Fall Symposium - Lihong Wang

McGovern 2013 Fall Symposium - Liho...

Added 12 months ago | 00:35:17 | 297 views

"Understanding Brain Disorders: Alzheimer's Disease"

"Understanding Brain Disorders: Alz...

Added 3 years ago | 00:54:10 | 6847 views