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 23 days ago

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


Viewed
2656 times

More from McGovern Institute for Brain Research

Emile Bruneau: Tweaking the Empathy Gap

Emile Bruneau: Tweaking the Empathy...

Added almost 2 years ago | 00:04:30 | 822 views

Optogenetics: A light switch for neurons

Optogenetics: A light switch for ne...

Added over 3 years ago | 00:04:51 | 9975 views

Meet Feng Zhang

Meet Feng Zhang

Added 3 years ago | 00:04:12 | 9655 views

Joel Z. Leibo, McGovern Institute Friends Fellow 2012-2013

Joel Z. Leibo, McGovern Institute F...

Added over 2 years ago | 00:02:59 | 4424 views

Understanding the brain basis of autism

Understanding the brain basis of au...

Added over 4 years ago | 00:04:35 | 8824 views

2011 Scolnick Prize Lecture: Bruce S. McEwen

2011 Scolnick Prize Lecture: Bruce ...

Added over 3 years ago | 01:05:00 | 3075 views