Cognitive development in young adulthood: neuropsychology & functional neuroimaging

The brain continues to develop into the early 20s (Giedd, 2004; Giedd et al.,
1999). Maturation of the cortex is characterized by a linear increase in white
matter volume and an inverted U-shaped pattern of changes in grey matter volume
(Giedd, et al., 1999). These trajectories are thought to result from
myelination, improving processing speed, and synaptic pruning, which increases
neural efficiency. Peak volume occurs earlier in females while total volume is
larger for males (Giedd, 2004). The frontal cortex, important for cognitive
control and social cognition, matures relatively late (Gogtay et al., 2004).
Recently, studies have compared the neural basis of cognitive control in
children, adolescents and adults. Differences in brain activation have been
found on several tasks, measuring processes such as working memory (Kwon,
Reiss, & Menon, 2002), inhibition (Rubia et al., 2006) and error processing
(Velanova, Wheeler, & Luna, 2008). A general reported pattern is an increase in
activation for task-relevant regions and attenuation of other areas with
development (Durston et al., 2006).
In the domain of social cognition, developmental changes have been observed in
fMRI experiments investigating emotion regulation (Monk et al., 2003), thinking
about intentions (Blakemore, den Ouden, Choudhury, & Frith, 2007) and
self-reflection (Pfeifer et al., 2009). These studies have shown involvement of
distinct brain regions, indicative of altered processing of social stimuli
during adolescence.
In contrast to the considerable amount of research on these specific life
periods, little is known about maturation in young adults. Between the ages of
18 and 25, several demographic and identity changes occur, including possible
entrance into higher education. This is therefore sometimes referred to as a
separate developmental period, named emerging adulthood (Arnett, 2000).
Consistent with changes in the environment and the protracted development of
the frontal cortex, continuing improvement of higher order functions can be
expected in young adults.
In addition, there are large individual differences in timing and efficiency of
maturational processes during childhood and adolescence, which plausibly extend
into young adulthood. A crucial determinant of individual differences is sex.
Brain development during adolescence starts at an earlier age in girls compared
to boys (De Bellis et al., 2001). Males and females engage different brain
areas when performing cognitive (Bell, Willson, Wilman, Dave, & Silverstone,
2006), emotional (Koch et al., 2007) and social (Krach et al., 2009) tasks,
which may also interact with age (Christakou et al., 2009).
Individual differences in development and concurrent neuropsychological
functioning might have consequences for education. Processes such as inhibition
and self-reflection are important for learning. Poor academic performance could
be the result of a not yet fully mature brain. Therefore, performance on
cognitive tasks and neural activation are possibly correlated with success in
university.
The aim of the current study is to investigate development in male and female
Medical students aged 18/19 years and 23/24 years. Differences between age
groups and sex on neuropsychological and neuroimaging tasks will be assessed.
In addition, grades and number of ECTS will be collected to relate cognitive
development to academic performance.

The primary objective of the current study is to investigate cognitive
development in young adults by comparing 18/19 year old and 23/24 year old male
and female students on a variety of neuropsychological and neuroimaging tasks.
The secondary objective of the current study is to explore the correlation
between neuropsychological functioning and brain activation patterns with
academic performance.

The current study employs a cross-sectional design with four groups: 20 males
aged 18/19, 20 females aged 18/19, 20 males aged 23/24 and 20 females aged
23/24. First year and last year students from the Medical Department at VU
University will be recruited. Grades and number of ECTS will be collected at
the end of the academic year, for which students are asked written permission.
The study consists of two sessions. The first session of two hours is the
behavioral part during which questionnaires, IQ tests and a neuropsychological
testbattery are administered. In addition, the experimental task for the second
session wil be practiced. In the second session of 1 hour a cognitive,
emotional and social task are performed in the fMRI scanner.

There are minimal risks associated with participation in this study. Slight
discomfort might be experienced by the participants during the fMRI session
because of the noisy environment and the requirement to move as little as
possible. Scanning time is limited to an hour to minimize burden for the
participants.