West Orange,
New Jersey
07052
Purpose:
The goal of this proposal is to examine the influence of feedback timing on learning and
brain function in individuals with moderate-to-severe traumatic brain injury (TBI), with and
without depression.
Study summary:
The overall objective of the proposed project is to investigate brain mechanisms during
learning in individuals with traumatic brain injury (TBI) with and without clinical
depression. Such knowledge can help guide rehabilitation strategies and reduce the burden of
TBI. Feedback about the accuracy of one's actions can improve learning by informing an
individual whether his/her action is correct or not. Individuals with depression have been
shown to have learning deficits and altered brain activity during learning compared to
healthy individuals when feedback is presented immediately. Impaired learning through
immediate feedback has also been observed in Parkinson's disease (PD) patients. However, PD
patients are able to learn from feedback when it is presented after a delay, engaging
separate neural mechanisms. Individuals with TBI have also been shown to have learning
deficits that are likely exacerbated by depressive symptoms. However, there is no evidence
directly examining the neural mechanisms of learning in individuals with TBI with and without
depression. The proposed research explores this distinction.
The elucidation of the neural mechanisms associated with learning in individuals with TBI
with and without clinical depression will inform 1) scientific knowledge about the effect of
depression on the injured brain, 2) TBI interventions about the effectiveness of feedback and
its timing, and 3) interventions for other clinical populations that require rehabilitation
and have high occurrence of depression. These objectives lie at the heart of the mission of
the National Institute of Neurological Disorders and Stroke as they will broaden "fundamental
knowledge about the brain and nervous system" associated with learning in TBI and the
knowledge gained from fulfilling the above objectives will "reduce the burden" of learning
deficits after TBI.
To test these hypotheses, participants will be recruited based on structured clinical
interview performed by the team member trained in psychiatric interviewing. Qualified
participants will perform an experiment during which they will first study word pairs outside
of the functional magnetic resonance imaging scanner. Then, in the scanner, participants will
see word pairs again in a multiple-choice format and will have to choose a match for each
word. After participants make their choice, feedback will be presented either immediately or
after a delay of 25 minutes. The experiment will end with the Test phase, which takes place
outside of the scanner, where participants will be presented with the words in the
multiple-choice format again so the influence of each feedback type on learning can be
evaluated.
Investigators hypothesize that depressed individuals with and without TBI will learn better
from delayed compared to immediate feedback, because learning through delayed feedback relies
on a different neural mechanism, which is not affected by depression and TBI, compared to
learning through immediate feedback. Non-depressed individuals without TBI and clinically
depressed individuals without TBI will also be recruited to delineate the influences of
depression from the impact of TBI on the brain.
Criteria:
Inclusion Criteria:
- I am between the ages of 18 and 65.
- I have been diagnosed with a TBI.
- I am an individual without TBI.
- I am right-handed.
- I have normal vision or corrected to normal vision.
- I can read and speak English fluently.
- I do or do not have a current diagnosis of Depression.
- I am not currently pregnant.
Exclusion Criteria:
- I have had a neurological disease, other than TBI.
- I have a significant history of alcohol or drug abuse as determined by study staff.
- I have metal in my body (shrapnel, piercing that cannot be taken off, retainer on the
upper jaw).
- I have something in my body that restricts me from having an MRI such as: an aneurysm
clip; implanted neural stimulator; implanted cardiac pacemaker or auto-defibrillator;
cochlear implant (internal hearing aids); ocular foreign body (e.g. metal shavings in
my eye), insulin pump or any pre- existing eye conditions (such as blurry vision,
seeing double, and abnormal eye movements).
- I experience discomfort in closed spaces (claustrophobia).
- I have been diagnosed with a neurologic illness such as epilepsy, brain tumors, etc.
(e.g. schizophrenia and bipolar disorder).
- I have had corticosteroid treatment less than a month ago as determined by study staff
review of my medications.
- I have been informed by my doctor that is it unsafe for me to receive regular MRI as
part of my medical care.