This study will use magnetic resonance imaging (MRI) to examine which areas of the brain are
involved in performing certain cognitive tasks. MRI uses a strong magnetic field and radio
waves to produce images of body tissues and organs that provide information about structure
and function of tissues.
Healthy normal volunteers between 21 and 40 years of age may be eligible for this study.
Candidates must be native English speakers and must be right-handed. They must have no
history of nervous system disease or psychiatric disorder. Candidates are screened with
questionnaires and a neurological examination.
Participants undergo functional MRI scanning. For this procedure, the subject lies on a
stretcher that moves into the scanner - a metal cylinder surrounded by a strong magnetic
field. During the scan, he or she is asked to make various decisions about whether words are
related or not. Two words are presented visually, separated by a variable time delay. The
subject reads both words, decides as quickly and accurately as possible whether the two
words are related or not, and indicates the answer by pressing a button. The test takes
about 2 hours. When it is completed, the subject completes a written questionnaire
concerning his or her experience in the scanner.
Objective. The purpose of the protocol is to extend the structured event complex (SEC) model
developed by the principal investigator. Grafman (Grafman, 1995) proposed that action
sequences are represented in form of SECs in the human prefrontal cortex (PFC). An SEC is a
goal-oriented set of events that is sequentially structured and represents thematic
knowledge, morals, abstractions, concepts, social rules, event features, event boundaries,
and grammars. There are both temporal and semantic associative relations between
subcomponents of SEC knowledge. We will investigate hypotheses regarding the role of
different regions within the PFC in processing associative relations. We will also
investigate how SECs differing in psychological dimensions such as temporal duration,
complexity, and familiarity are represented and activated in the PFC. We will further
examine the temporal and semantic organization of SEC subcomponents by investigating how the
goal and outcome structure of event knowledge is represented and activated in the PFC.
Further, we will investigate how the temporal location of events within SECs are represented
and activated in the PFC. We will also investigate how goals and outcomes specifying the
temporal order and duration of SEC subcomponents are processed within the PFC. Additional
objectives are to (1) investigate the neural representation of human emotions and
decision-making based on utility estimation; (2) investigate the relationships between
cognitive and neural substrates of moral emotions and judgment (Moll et al., 2002a; Moll et
al., 2002b) with those of the SEC model developed by the principal investigator (Grafman,
1995); and (3) probe a new construct of cognitive dimensions incorporating critical
explanatory variables in social cognition such as moral emotions and social event knowledge.
Study Population. In nineteen separate studies, healthy, normal adult volunteers will
participate in experiments dealing with different kinds of associative relations in SECs
using functional magnetic resonance imaging (fMRI).
Design. The experiments we are conducting will employ within-subject, rapid event-related
fMRI designs to determine whether different types of SEC associative and other types of
relations are stored in dissociable networks in the PFC. In nineteen experiments; we hope to
automatically activate lexical, event-based and temporally-based associative and other types
of relations in SECs.
Outcome Measures. The data collected will consist of accuracy and response time measures of
cognitive performance reflecting automatic priming of associative relations and fMRI
activation images corresponding to each kind of associative relation, and accuracy and
response time measures of cognitive performance reflecting how temporal duration,
complexity, and familiarity are represented and activated. Experiments 10 and 11 will also
record donation choices made by the subjects. The results gained from this protocol will
provide further evidence for modifying, supporting, or rejecting aspects of the SEC model,
and will provide further evidence for modifying, supporting, or rejecting aspects of a
framework of social cognition such as moral behavior and social event knowledge.
- INCLUSION CRITERIA:
In all the studies, subjects will consist of healthy, native English-speaking,
right-handed volunteers, as measured by the Edinburgh Handedness Inventory.
Subjects will range in age from 21 to 40 years old and they will be included regardless of
race or gender.
Non-native English speakers and non-right handers will be excluded as mentioned above, as
will non-neurologically normal volunteers.
Subjects younger than 21 and older than 40 will be excluded.
A pregnancy test will be employed with all women of childbearing age. The results must be
negative in order to proceed with the MRI.
Subjects with any of the following: aneurysm clip; implanted neural stimulator; implanted
cardiac pacemaker or auto-defibrillator; cochlear implant; ocular foreign body, e.g. metal
shavings; permanent eyeliner; insulin pump; or irremovable body piercing will be excluded
from the study due to the possible dangerous effects of the magnet upon metal objects in
Subjects taking central nervous system active medications will be excluded.