This study has several parts. One part will examine the influence of factors such as
personality and past experience on reactions to unpleasant stimuli. Others will examine the
effect of personality and emotional and attentional states on learning and memory.
When confronted with fearful or unpleasant events, people can develop fear of specific cues
that were associated with these events as well as to the environmental context in which the
events occurred via a process called classical conditioning. Classical conditioning has been
used to model anxiety disorders, but the relationship between stress and anxiety and
conditioned responses remains unclear. This study will examine the relationship between cued
conditioning and context conditioning . This study will also explore the acquisition and
retention of different types of motor, emotional, and cognitive associative processes during
various tasks that range from mildly arousing to stressful.
Objective: Fear and anxiety are adaptive responses to different types of threats. Fear is a
short-duration response evoked by explicit threat cues. Fear can best be studied using
Pavlovian fear conditioning. Studies 1 and 2 examine learning processes underlying fear
conditioning as well as the influence of cognitive and affective processes on these learning
processes. Anxiety is a more sustained state of apprehension evoked by unpredictable threat.
Study 2 examines the interactions between anxiety induced experimentally and cognitive
processes. Specifically, we seek to 1) characterize the effect of anxiety on key cognitive
processes including working memory, attention control, conflict, and learning and memory. 2)
examine the extent to which performance of cognitive tasks distract from anxiety, and 3) how
physical exertion influences anxiety and its effects on cognition. Study 3 examines the
effects of memory
retrieval on extinction.
Study population: This more-than-minimal-risk protocol will test medically and
psychiatrically healthy volunteers aged 18-50. Pregnant or nursing women will be excluded.
Method: Fear and anxiety will be measured using the startle reflex to brief and loud sounds.
Fear conditioning will be assessed using shock as unconditioned stimulus. Cognitive
performance will be examined during periods of unpredictable shock anticipation or prior to
giving a speech.
Outcome measures: The study will include cognitive performance and measure of aversive
states, primarily the startle reflex.
- INCLUSION CRITERIA:
- Males and females
- Age 18-50
- Any current ongoing medical illness
- Current Axis I disorders
- Past significant psychiatric disorders (e.g., psychotic disorders) according to DSM-IV
- Current alcohol or substance abuse according to DSM-IV criteria
- History of alcohol or substance dependence based on DSM-IV criteria within 6 months
prior to screening
- Current psychotropic medication use
- Current or past organic central nervous system disorders, including but not limited to
seizure disorder or neurological symptoms of the wrist and arms (e.g., carpal tunnel
syndrome). The latter exclusion is for shock studies only.
- Negative urine toxicology screen
- For exercise substudy:
- History of exercise intolerance
- History of heart disease
- History of pulmonary disease, other than controlled, non-exercise-induced asthma
- History of uncontrolled diabetes
- Resting heart rate > 90 BPM
- Resting systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg
- Peripheral condition making completion of the exercise protocol impossible, such
as severe osteoarthritis or chronic pain
- Clinically significant abnormal EKG as determined by MD or DNP
- For active avoidance substudy:
- Diagnosis of color blindness