Cerebral Cortical Adaptations Associated
with Visuomotor Practice
SCOTT E. KERICK1, LARRY W. DOUGLASS2, and BRAD D. HATFIELD1
1Department of Kinesiology and 2Department of Animal Sciences, University of Maryland, College Park, MD
ABSTRACT
KERICK, S. E., L. W. DOUGLASS, and B. D. HATFIELD. Cerebral Cortical Adaptations Associated with Visuomotor Practice. Med.
Sci. Sports Exerc., Vol. 36, No. 1, pp. 118–129, 2004. Purpose: Electroencephalographic (EEG) recordings were examined at the
temporal (T3, T4) regions of the cerebral cortex in novice pistol shooters (N
11) over a training period of 12–14 wk to determine
changes in activation. Mean alpha power and its rate of change were hypothesized to increase in the left temporal region during aiming
from early to late season as participants improved their accuracy and reduced cognitive effort. Methods: Event-related alpha II power
(ERAP; 11–13 Hz) was examined over a 5-s period preceding the trigger pull during shooting (SH) and two control conditions (resting
baseline, BL; and postural simulation, PS) at early (time 1), middle (time 2), and late (time 3) practice. Results: Mean levels of ERAP
increased at T3 from the beginning to the end of the training period during both SH and PS, but not BL, whereas no such change in
mean level of ERAP was noted at T4 during any of the three conditions. The practice-related cortical adaptation during SH covaried
with an increase in shooting percentage over the season. A higher rate of increase in ERAP during the 5-s aiming period of SH relative
to that at PS and BL was also observed throughout training at both T3 and T4. Exploratory analysis of global power (sites F3, Fz, F4,
C3, Cz, C4, P3, Pz, and P4) revealed that ERAP increased during SH from time 1 to time 3 at all sites except Fz and Pz, whereas only
one site (C4) revealed an increase during BL. Conclusions: The reduction in cortical activity is likely due to sensorimotor integration
and less cognitive effort due to automaticity. Key Words: ELECTROENCEPHALOGRAPHY, MOTOR LEARNING, ATTENTION,
MEMORY
During the early stages of motor skill learning, per-formance of an unfamiliar task is uncoordinated andrequires considerable cognitive effort in making
decisions and executing movement (4,5,23,32). Novices
must test untried solutions in their response repertoire in the
attempt to discriminate between effective and ineffective
response strategies (i.e., multiple degrees of freedom). How-
ever, with sustained practice, procedural memory evolves
through a combination of implicit and explicit learning (2).
Plasticity of the nervous system allows for reorganization of
neural communication, and the development of an internal
model via electrochemical adaptations and synaptic trans-
mission among cortical and subcortical neurons. Such ad-
aptations facilitate perceptuomotor integration, neuromus-
cular coordination, and the quality and consistency of motor
skills. Consequently, lower-order skill components of the
task, within the hierarchy of skilled components, demand
less conscious regulation or executive control and perfor-
mance of the task becomes more autonomous (1,5,8,24,31).
For example, a novice target shooter must first learn the
rules and strategies of competition, as well as master the
fundamental shooting skills such as the postural stance, gun
hold, aim, and timing of the trigger pull. Awareness of
visual and kinesthetic feedback and the detection of errors
require conscious thought and attention to technical points
relevant to skill execution. However, with sustained prac-
tice, the individual becomes more familiar with the rules and
strategies and is able to execute the fundamental skills of the
task with greater automaticity, a state which functions to
reduce task complexity and cognitive effort (5,8,24).
Few studies have investigated neurocognitive adaptations
over extended periods of practice and instruction in real-
world sport environments. In one of the few published
longitudinal studies, Landers et al. (22) observed that novice
archery students exhibited increased electroencephalo-
graphic (EEG) alpha power (12 Hz) over the left, but no
changes over the right, temporal region in association with
performance improvement after 14 wk of practice. Consid-
ering the well-established inverse relation between alpha
power and cortical activation, this finding is consistent with
an explanation of decreased cognitive effort (i.e., working
memory) and development of an internal model as a result
of practice, whereas the maintenance of right temporal ac-
tivation would seem logical in light of the role of the right
hemisphere in visuospatial processing, a primary compo-
nent of the task. Research comparing expert and novice
participants in target sports provides further support of this
notion. Consistent findings have revealed that skilled per-
formers exhibit greater alpha power (8–13 Hz) in the left
temporal region during shot preparation (i.e., 5- to 8-s aim-
Address for correspondence: Bradley D. Hatfield, Department of Kinesi-
ology, University of Maryland, College Park, MD 20742-2611; E-mail:
bh5@umail.umd.edu.
Submitted for publication April 2002.
Accepted for publication August 2003.
0195-9131/04/3601-0118
MEDICINE & SCIENCE IN SPORTS & EXERCISE®
Copyright © 2004 by the American College of Sports Medicine
DOI: 10.1249/01.MSS.0000106176.31784.D4
118

ing period) relative to less skilled participants but manifest
no differences in the right temporal region (11,14,28).
Synchronous oscillations of large assemblies of cortical
neurons are an indication of increased interconnectivity and
coherent organization among brain regions (19,25,27). As
such, left temporal alpha synchronization may reflect inhi-
bition of explicit working memory and a reduction in task-
irrelevant brain processes. Attenuation of desynchronized
cortical activity is important as desynchronized activity
could potentially interfere with implicit procedural memory
processes involved in sensorimotor integration (2,18). In
light of the established role of the temporal regions in
working memory and visual perception, and the relevance of
such processes to the establishment of internal models to
guide psychomotor activity, there is justification for the
examination of the left and right temporal regions as done in
previous marksmanship studies (9–12,14,17,22,28). How-
ever, much of the research that has examined cerebral cor-
tical activity in relation to psychomotor skill has been cross-
sectional (11,14,28) or has involved assessment of cortical
change within single practice sessions. Additionally, the
assessment of cortical activation in these studies has typi-
cally been limited and confined to the temporal and occipital
regions. Therefore, further investigation is needed to exam-
ine cortical adaptations associated with practice over ex-
tended periods (i.e., weeks or months) and to examine a
more broadly distributed spatial topography to determine
the extent of practice-related change in cortical activity.
Accordingly, the present research examined regional (left
and right temporal) as well as global cortical adaptations of
first-year collegiate pistol shooters associated with practice
over a time period of 14 wk and employed EEG signal
processing techniques designed to enhance temporal reso-
lution and sensitivity to task-related neurocognitive activity.
A major advantage of EEG is that it provides a quantitative
measure of electrical potential fluctuations of cortical pyra-
midal neurons with relatively high temporal resolution in
contrast to other neuroimaging techniques. However, the
resolution of EEG spectral estimates derived in previous
research was limited to 500–2500 ms using fast-Fourier
transform (FFT), perhaps concealing information about the
dynamic changes in alpha power over the preparatory pe-
riod. Application of alternative signal processing techniques
such as event-related synchronization (ERS; 26) and tem-
poral spectral evolution (TSE; 7) allow for higher temporal
resolution of EEG spectral estimates. Therefore, a variation
of ERS and TSE, event-related alpha power (ERAP), was
implemented in the present study in order to increase the
temporal resolution of alpha power estimates (125 ms), as
was applied in a recent study of rifle marksmen (17). The
broad alpha band (7–13 Hz) forms the peak of the EEG
power spectrum, and its amplitude is attenuated in response
to psychological demand in a regionally specific manner.
However, greater specificity of cortical response to task-
related demands can be achieved by isolation of higher
alpha frequency components (alpha II; 11–13 Hz) from the
lower frequency components (alpha I; 8–10 Hz) as the latter
are more indicative of generalized arousal processes
(11,17,19,27,31). Specifically, ERAP in the alpha II fre-
quency band was extracted from response-locked EEG ep-
ochs because of its sensitivity to task-specific attentional
processes.
Mean ERAP was predicted to increase with practice over
time in the left temporal region as an index of increased
functional organization (i.e., decreased reliance on working
memory) during the sampled aiming period (5 s to 0 s).
Additionally, a higher rate of increase in ERAP (i.e., slope
of power estimates over the 5-s aiming period) was pre-
dicted for the left temporal region with practice as a dy-
namic index of increased attentional focus during shot prep-
aration. No such changes were predicted for the homologous
right region because the visuospatial demands of aiming
should remain relevant to task execution and, therefore,
stable (9). Additionally, no changes were hypothesized for
either of two control conditions (resting baseline, BL; and
postural simulation, PS). Finally, exploratory analysis of
ERAP mean power and slope was conducted over a spatially
distributed topography to determine the extent of cerebral
cortical changes associated with practice.
METHODS
Participants
Thirteen (two female) right-handed participants who were
ipsilateral eye dominant (age range 18–22 yr, mean

19.08, SD
1.50), with no shooting experience, were
recruited from a pistol club at a United States Naval Acad-
emy. All of the participants completed a consent form that
had been approved by the institutional review boards of both
the military academy and the university with which the
investigators were affiliated. Two individuals (one female)
ceased participation with the club before completing their
third test session. A sample size of 11 subjects was suffi-
cient to detect a difference of 0.8 of the standard deviation
of the differences in ERAP recorded at T3 from time 1 to
time 3 (an effect size of 54% of the control) with 70% power
when tested at the 0.05 level of significance. Therefore,
statistical analyses were applied to data from the 11 remain-
ing participants.
Measures
EEG preparation and acquisition. A stretchable
electrode cap (ElectroCap Inc., Eaton, OH) was fitted to the
participant’s head in accord with standards of the interna-
tional 10–20 system for recording EEG (15). The montage
consisted of 11 sites (F3, Fz, F4, C3, Cz, C4, T3, T4, P3, Pz,
and P4) referenced to the left mastoid online and re-refer-
enced to digitally linked-mastoids offline. Electro-ocular
activity (EOG) was measured with a bipolar electrode mon-
tage using two 10-mm diameter electrodes (Grass E5GH)
attached superior and inferior to the orbital fossae of the
right eye for vertical eye-movement (VEOG) and to the
external canthi for horizontal eye-movement (HEOG). All
EEG data were recorded and stored using Neuroscan soft-
ware (Ver. 4.1) installed on a Gateway 2000 133-MHz
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