Cognitive control is the ability to guide attention,
thought, and action in accord with goals or intentions.
One of the fundamental mysteries of neuroscience is how
this capacity for coordinated, purposeful behavior arises
from the distributed activity of many billions of neurons
in the brain. Several decades of cognitive and neuroscientific
research have focused on the mechanisms by which control
influences processing (e.g., attentional effects in sensory
processing, goal-directed sequencing of motor output,
etc.), and the brain structures upon which these functions
depend, such as the prefrontal cortex, anterior cingulate
cortex, basal ganglia, and brainstem neuromodulatory systems.
However, we still have a poor understanding of how these
systems give rise to cognitive control. Our work seeks
to develop formally explicit hypotheses about the functioning
of these systems, and to test these hypotheses in empirical
studies. An important motivation for this work is the
development of a theoretically sound foundation for research
on the relationship between disturbances of brain function
and their manifestation as disorders of thought and behavior
in psychiatric illness.
Neural network models are developed as a way of articulating
precise hypotheses about the function of particular brain
systems, and their role in cognitive control. This work
seeks to bridge the traditionally disparate levels of
analysis of neurophysiology, systems neuroscience, and
cognitive psychology. Projects focus on the function of
systems considered to be critical for cognitive control,
including (a) the role of prefrontal cortex in biasing
attention and response selection in posterior structures;
(b) the role of brainstem dopamine systems in regulating
learning and updating of representations in prefrontal
cortex; (c) the role of the anterior cingulate cortex
in monitoring performance, and its influence on adaptations
in control; and (d) the influence of locus coeruleus and
norepinephrine on attentional state. In many cases, modeling
work has led to novel predictions about neurophysiolgical
mechanisms underlying systems-level function, such as:
(a) gain control as a mechanism for dopaminergic neuromodulation;
(b) the role of dopamine in coordinating reinforcement
learning and the gating of information into prefrontal
cortex; (c) the influence of electrotonic coupling on
population dynamics within the locus coeruleus; and (d)
the effects of changes in locus coeruleus physiological
state on attentional mode. In other cases, this work has
led to novel hypotheses about system level function, such
as the response of anterior cingulate cortex to conflict
in processing and its influence on adaptive changes in
cognitive control. This work has also predicted, and led
to the discovery of, new anatomic relationships, such
as projections from the anterior cingulate cortex to locus
coeruleus.
