Northwestern 2004

1
Center for Integrative Cognitive Neuroscience

• Established with Provost AVCF funds in 2000
• Jeffrey Schall, Ph.D., Director
• 52 Faculty from 14 Departments in
• College of Arts and Sciences
• Peabody College of Education
• School of Engineering
• School of Medicine
• Support for research, graduate training and
  undergraduate education in integrative and
  cognitive neuroscience
• Extensive coordination with KC, VUIIS and VVRC
• http//cicn.vanderbilt.edu/

2
Vanderbilt Vision Research Center

• Established in 1989
• Jeffrey Schall, Ph.D., Director
• 42 Faculty from 13 Departments in
• College of Arts and Sciences
• Peabody College of Education
• School of Engineering
• School of Medicine
• Support for research, postdoctoral and graduate
  training in eye and vision science
• Home for NEI Core grant and NEI Training grant.
• http//vision-research.vanderbilt.edu/

3
CICN and VVRC facilitate research on brain
systems, behavior and cognition.

• For example, attention deficit and hyperactivity
  disorder (ADHD)
• Inattention
• Hyperactivity
• Impulsivity
• Diagnosis and treatment requires effective
  behavior testing.
• The stop signal task probes peoples ability to
  control thought and action

4
Green light, red light task.
GO
5
Performance in the stop signal task can be
explained by a mathematical model of a race
between the process that makes you GO and the
process that makes you STOP. This model permits
determination of how long it takes to stop, the
stop signal reaction time.
Kids with ADHD have longer than normal stop
signal reaction time.
6
Movements are initiated when certain neurons
discharge a certain amount. The variability in
time to start moving arises from variability in
the time taken by neurons to reach the trigger
threshold.
How the brain produces movements
Activation
0.0
0.1
0.2
Time from stimulus (sec)
7
In the stop signal task, movements are withheld
if and only if the movement neurons are prevented
from reaching the threshold.
Go
Activation
0.0
0.1
0.2
0.3
0.4
Time from stimulus (sec)
8
Neurons in medial frontal lobe signal errors and
success
Activation
0.0
-0.2
0.2
0.4
Time from movement (sec)
9
Error signals from single neurons correspond to
scalp potentials
10

• A plausible link between genes, brain circuits
  and behavior
• Error monitoring signals are based on the
  activation of dopamine neurons that comprise the
  brains reward system
• Abnormal dopamine transporter (DAT) linked to
  ADHD
• Hypothesis that abnormal DAT causes impulsivity
• Test by coordinated screening of the DAT gene
  and performance on the stop signal task in ADHD
  subjects

Error-related negativity