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The Journal of Neuroscience, September 15, 1999, 19(18):8043-8048
A Blueprint for Movement: Functional and Anatomical
Representations in the Human Motor System
Michel
Rijntjes1,
Christian
Dettmers1,
Christian
Büchel2,
Stefan
Kiebel1,
Richard S. J.
Frackowiak2, and
Cornelius
Weiller1
1 Department of Neurology, Friedrich Schiller
University, 07740 Jena, Germany, and 2 Wellcome Department
of Cognitive Neurology, London WC1 NBG, United Kingdom
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ABSTRACT |
Despite a clear somatotopic organization of the motor cortex, a
movement can be learned with one extremity and performed with another.
This suggests that there exists a limb-independent coding for
movements. To dissociate brain regions coding for movement parameters
from those relevant to the chosen effector, subjects wrote their
signature with their dominant index finger and ipsilateral big toe, and
we determined those areas activated by both conditions using functional
magnetic resonance imaging. The results show that movement parameters
for this highly trained movement are stored in secondary sensorimotor
cortices of the extremity with which it is usually performed, i.e., the
dominant hand, including dorsal and ventral lateral premotor cortices.
These areas can be accessed by the foot and are therefore functionally
independent from the primary representation of the effector. Thus,
somatotopy in secondary structures in the human motor system seems to
be defined functionally, and not on the basis of anatomical representations.
Key words:
human; motor system; movement; premotor cortex; visuospatial; representation; fMRI
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INTRODUCTION |
Based on anatomical and functional
criteria, the cortex of the human brain is divided in primary,
secondary, and tertiary areas, with anatomical representation
predominantly in primary cortex and modality-independent, functional
representation in tertiary structures (Mesulam, 1987 ). The primary
sensorimotor cortex shows a clear somatotopic representation of body
parts (Penfield and Boldrey, 1938), albeit with some overlap
(Förster, 1936; Schieber and Hibbard, 1993; Sanes et al., 1995).
This area has the strongest anatomical connections with the limbs, and
measuring cerebral activity with functional imaging tools like positron emission tomography or functional magnetic resonance imaging during a
hand movement will show an activation of the primary hand region, irrespective of the task. Additional involvement of secondary and
tertiary cortices will depend on the complexity of the paradigm, and
activation in secondary motor cortices is generally interpreted as
higher-order but still modality-specific processing, e.g., planning,
preparation, imagining, selection, or internal generation of the
movement (Passingham, 1993). It is implicitly assumed that this
additional activation of secondary sensorimotor cortices is also
limb-specific, since it is always seen as reflecting inherent aspects
of the investigated movement, usually performed by the hand (Passingham
1989; Sakata and Taira, 1994; Jackson and Husain, 1996, Sanes and
Donoghue, 1997; Rizzolatti et al., 1998). However, when making a
movement, the parts of the brain involved in its execution depend on
two determinants: on the extremity that is used and on the kind of
movement that is being made. The observation that the same movement can
be executed by different effectors has been called "motor
equivalence" by Lashley (1930) and suggests that movement parameters
are coded independently from the limb representation itself. The
demonstration that movement parameters are stored independently from
the executing extremity and can be accessed by another may have
implications for the rehabilitation of patients with circumscribed
brain lesions, like stroke.
Signing one's name is a very characteristic hand movement. However,
when standing on the beach, you can write your signature with your toe
in the sand, retaining the personal characteristics (Rosenbaum, 1991;
Rothwell, 1995). Apparently the foot, although it has never learned
this movement, has immediate access to a motor program for the hand. By
dissociating brain structures where parameters for a motor program are
stored from those relevant to the chosen effector, it should be
possible to separate anatomical and functional representations in the
motor system. To this purpose, we chose signing as a movement that is
exclusively associated with one extremity, i.e., the dominant hand, and
had it perform with another.
Using functional magnetic resonance imaging, the first step was to
determine the anatomical representations of finger and toe, as defined
by a generic, zigzagging movement, which was performed either by the
index finger or the big toe by nine healthy, right-handed subjects. To
find areas containing the limb-independent, functional representation
of signing, we had the same subjects sign with their right index finger
and with the right big toe and identified the cerebral structures
common to both.
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MATERIALS AND METHODS |
The subjects (eight male, one female, mean age, 32 years) were
right-handed according to the Edinburgh Inventory (Oldfield, 1971).
They signed approximately once every 4 sec with their right dominant
index finger or right big toe. For the zigzagging conditions, subjects
were requested to perform a left-to-right zigzagging movement with the
same finger and toe. Both the singing and the zigzagging conditions
involved a small side-to-side movement of the hand and foot as well,
but the lower arm and lower leg were supported comfortably to prevent
innervation of proximal muscles. Signing is a more complex movement
than zigzagging, but to minimize the differences between the movements,
subjects exercised the zigzagging conditions before scanning to have
the same frequency as signing, filling out the same space as their
individual signatures, to ensure that the zigzagging conditions had
similar spatial and directional properties as signing. The number of
individual signatures and zigzagging movements were counted by an
observer looking into the scanner and differed maximally by two
movements at the end of the experiment. The space filled out by signing
and zigzagging remained constant and was approximately the same. Eyes
were closed during all conditions, including rest. Off-line
electrooculographic and electromyographic recordings (10 Hz-1 kHz
filter; 0.1 sec/division; sensitivity, 100 mV) during 2.5 min
showed that there were no task-associated eye movements and no
coinnervation of one extremity when moving another.
Neural activity was indexed by monitoring blood-oxygen
level-dependent signal changes with functional magnetic
resonance imaging. Data were acquired at the Wellcome Department of
Cognitive Neurology in London with a 2 T magnetic resonance imaging
(MRI) (Magnetom Vision, Siemens, Erlangen, Germany) whole-body
scanner equipped with a head volume coil. Contiguous multislice
T2*-weighted images [TE = 40 msec, 90 msec/image, 64 × 64 pixels (voxel size, 3 × 3 × 3 mm)] were obtained with
echoplanar imaging using an axial slice orientation. The volume covered
the whole brain (14.4 cm). The effective repetition time was 4.0 sec
per volume. In all conditions (four movement conditions and one rest
condition), six image volumes were acquired, lasting 24 sec each. Each
movement condition was alternated with one rest condition. The four
conditions containing a movement (six images each) were performed nine
times in a random order. Alternated with rest scans (six images each),
this resulted in 432 scans in total. At the end of each scan, the
subject was instructed acoustically about the condition in the next
one. Scans were realigned to each other and coregistered to an
individual three-dimensional T1-weighted scan (voxel size, 1 × 1 × 1 mm). Image transformation into the stereotactic anatomical
space was followed by smoothing with a 6 mm isotropic Gaussian kernel.
Data analysis was performed by modeling the different conditions as reference waveforms (i.e., box-car functions convolved with a hemodynamic response function) in the context of the general linear model as employed by SPM96 (Frackowiak et al., 1997). Significant increases were tested with t statistics, corrected for
multiple comparisons, and displayed as a statistical parametric map,
which was projected onto the averaged anatomical T1 image from the nine subjects. Threshold for significance was set at p < 0.001. Two kinds of group comparisons were performed. The first was
categorical, comparing zigzagging versus rest and signing versus rest.
The second was conjunctional, identifying structures that were common to signing with either digit as compared to zigzagging, i.e., finger
signing versus finger zigzagging and toe signing versus toe zigzagging
(Price and Friston, 1996). For the conjunctional analysis, voxels with
an interaction between conditions were rejected. The study was approved
by the local ethics committee. Informed consent of all subjects was
obtained before scanning.
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RESULTS |
Anatomical representation as defined by simple,
repetitive movements
The zigzagging conditions, as compared with rest, activated most
components of the sensorimotor system (Figs.
1, 2).
Somatotopic segregation of hand and foot representations were found in
the contralateral primary sensorimotor cortex, the adjacent superior parietal lobe (Brodmann area 5), supplementary motor area (SMA), the
anterior cingulate, thalamus, basal ganglia (putamen, caudate nucleus,
globus pallidus), cerebellar hemisphere, and vermis, following known
primate anatomy and previous imaging studies (Nitschke et al., 1996;
Fink et al., 1997; Lehericy et al., 1998). Our data also showed
somatotopy for finger and toe in the dorsal lateral premotor cortex
(PMd), in accordance with nonhuman primate studies (Kurata, 1989; He et
al., 1993; Godschalk et al., 1995). The ventral activation of the
precentral gyrus (Brodmann area 6) was located in the part of the
ventral premotor cortex (PMv) that has been denoted F4 in monkeys
(Matelli et al., 1985; Fink et al., 1997). Zigzagging with the finger
gave rise to two foci of activation in the intraparietal sulcus. There
is considerable individual variation in the course of this sulcus, but
analysis of the normalized T1-weighted anatomical images confirmed that
the peaks of activations were in the intraparietal sulcus in each
subject. The medial peak, commensurate with the activation in Brodmann
area 5, probably corresponds to the middle intraparietal area (MIP),
regarded as an intraparietal extension of area 5 (Caminiti et al.,
1996). The lateral peak was at the fundus of the intraparietal sulcus, where the ventral intraparietal area (VIP) is located in monkeys (Colby
et al., 1993). Zigzagging with the toe showed no activation in the
intraparietal sulcus or in the premotor cortex of the hand at the level
of the primary hand representation, even when the threshold was lowered
to p < 0.05. Zigzagging either with the finger or the
toe activated the secondary sensorimotor system, consisting of the
frontal operculum and secondary sensory cortex (SII).
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Figure 1.
Anatomical and functional representations: surface
views. Cortical activations of the different comparisons in the group
of nine normal subjects. Activations in sulci as well as on gyri are
projected on the surface of superior and lateral views of the brain.
Top, Toe zigzagging versus rest (left)
and toe signing versus rest (right).
Bottom, Finger zigzagging versus rest
(left) and finger signing versus rest
(right). Right, Areas commonly activated
in the conjunctional analysis of the two comparisons: finger signing
versus finger zigzagging and toe signing versus toe zigzagging. In the
zigzagging conditions, there is a clear somatotopic segregation for the
toe in the midline and for the finger on the convexity, with some
overlap in SMA and PMd (see Fig. 2, transverse slices).
Zigzagging both with the toe and finger activated part of the PMv on
the precentral gyrus, as well as the secondary sensorimotor system in
the frontal operculum and secondary sensory cortex. Signing with the
finger activated the same areas as zigzagging with the finger, with the
addition of the posterior parietal cortex and the occipitotemporal
junction. Signing with the toe activated the same areas as zigzagging
with the toe, plus the posterior parietal cortex and the
occipitotemporal junction, with the addition of the intraparietal
sulcus and the premotor cortices on the convexity, i.e., the secondary
sensorimotor areas of the finger. The conjunctional analysis of the
signing conditions versus the respective zigzagging conditions revealed
that the areas involved in signing, irrespective of the performing
extremity, are the secondary sensorimotor areas that are part of the
anatomical finger representation. These comprise PMv, PMd, and the
intraparietal sulcus. Additionally, signing both with the finger and
the toe activated the occipitotemporal junction and the posterior part
of the superior parietal cortex. Signing activated the respective
primary sensorimotor cortices of finger and toe, area 5, SII, and the
frontal operculum to the same extent as zigzagging. Therefore, these
areas are not involved in the extremity-independent representation of
this automated movement.
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Figure 2.
Anatomical and functional representations: axial
slices. Transverse slices with activations superimposed on the averaged
T1 images of the nine subjects. Neurological convention (left = left), numbers refer to millimeters relative to the intercommissural
line. Displayed are activations at the level of PMd of the hand (48-58
mm), SMA (52 mm), VIP and PMv (38 mm), thalamus and putamen (8 mm),
cerebellar vermis ( 10 mm), and the cerebellar hemisphere (20 mm).
The slice at 38 mm was pitched down by 6° to capture both VIP and
PMv. The three circles in the diagram represent three
comparisons: zigzagging with the finger versus rest, zigzagging with
the toe versus rest, and the conjunctional analysis of areas common to
signing with finger and toe versus zigzagging with either. The areas
where these comparisons overlap or not are coded in separate colors.
Red, Areas activated by finger zigzagging only,
excluding the overlap with the conjunctional analysis of signing with
the finger and the toe. Blue, Areas activated by toe
zigzagging only, excluding the conjunctional analysis of signing with
the finger and the toe. Dark purple, Overlap of
activations by zigzagging with the finger and the toe, excluding the
conjunctional analysis of signing with the finger and the toe.
Green, Areas involved in the conjunctional analysis of
signing with the finger and the toe, additional to the zigzagging
conditions. The ipsilateral and contralateral activations for signing
were slightly larger than for zigzagging in several areas, because
signing is a more complex movement than zigzagging (see Discussion).
Light purple, Areas activated by zigzagging with the
finger and the toe, which are also involved in signing with either.
Black, There were no areas found that are activated by
zigzagging with the toe and that are also involved in the conjunctional
analysis of signing with the finger and the toe. Yellow,
Areas that were found in the conjunctional analysis of signing with
finger and toe versus zigzagging with either and were also found in
zigzagging with the finger only, excluding areas activated by finger
and toe zigzagging. These areas comprised secondary cortices, thalamus,
and cerebellum as part of the anatomical finger representation,
excluding the primary sensorimotor cortex, area 5, basal ganglia,
frontal operculum, and secondary sensory cortex. Signing did not
activate exclusive toe areas. Thus, the limb-independent motor
representation of signing is confined to finger areas, excluding
exclusive toe areas, with additional activation of the posterior
parietal lobe and occipitotemporal junction.
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Functional representation as defined by a typical hand movement
performed by finger and toe
Signing with the finger, compared with rest, activated the same
areas as zigzagging with the finger, with the addition of the posterior
parietal cortex and the occipitotemporal junction (Figs. 1, 2). Singing
with the toe, compared with rest, activated the same areas as
zigzagging with the toe, also with the addition of the posterior
parietal cortex and the occipitotemporal junction. Signing with the toe
activated the intraparietal sulcus and the premotor cortices on the
convexity as well, i.e., secondary sensorimotor areas of the
finger. The cerebral structures that were involved in
signing independently of the executing extremity were defined by
activations that were common to the comparisons finger signing versus
finger zigzagging and toe signing versus toe zigzagging. This
conjunctional analysis showed that signing with either limb was
associated with an activation in areas that belonged to the anatomical
finger representation in secondary cortices, as determined by the previous zigzagging conditions. These included the anterior part
of the PMd, PMv, SMA, area MIP and VIP in the intraparietal sulcus, the
thalamus, and the cerebellar hemispheres (Figs. 1, 2).
During signing, no significant voxels were found in the areas that were
activated by zigzagging with the toe only. Activations additional to
the zigzagging conditions were observed in the posterior part of the
superior parietal cortex, probably corresponding to Brodmann area 7, and at the occipitotemporal junction, at the same location where the
visual motion center (V5/MT) has been described (Watson et al., 1993).
All subjects reported a strong visual image of their signature while signing.
Statistical comparison of the signing and the zigzagging conditions
revealed that there was no significant difference in activation of the
respective primary sensorimotor cortices, as well as in area 5, basal
ganglia, frontal operculum, and secondary sensory cortex. Therefore,
these areas were not found in the conjunctional analysis of
extremity-independent movement representations.
| |
DISCUSSION |
The execution of a typical hand movement, even when it is
performed by the toe, involves "hand areas" at all levels of the anatomical hand representation, including secondary sensorimotor cortex, the thalamus, and the cerebellum, but excluding the primary sensorimotor cortex and basal ganglia. How can this be explained? Experimental results in humans show that movement trajectories are
planned in an internal model of visually based kinematic coordinates (Soechting and Flanders, 1989; Wolpert et al., 1995). In nonhuman primates, a ventral and a dorsal parietofrontal network have been implicated in such visuomotor transformations of movement (Passingham, 1989; Kalaska et al., 1997; Rizzolatti et al., 1998), with PMv and PMd
as the prerolandic components of these respective systems.
The ventral system, including VIP and PMv, has anatomical connections
to the occipitotemporal junction (area V5/MT). This area, originally
described as a visual motion center (Watson et al., 1993), has
directional specificity (Tootell et al., 1995) and can be activated
during illusory movement (Parsons et al., 1995). Apparently, because
eyes were closed in all our tasks, V5/MT can be activated even without
visual sensory input. V5/MT projects to VIP in the intraparietal sulcus
(Colby et al., 1993), which is connected mainly with PMv (Matelli et
al., 1994). In both these areas, many neurons are bimodal, in the sense
that they respond to stimuli in both tactile and visual fields. These visual receptive fields extend from the tactile receptive fields into
adjacent space and move as a unit with it (Fogassi et al., 1996;
Graziano et al., 1997). This system, coding for target localization in
peripersonal space in body part-centered coordinates, was activated contralateral to the signing hand or foot.
The dorsal system includes MIP and PMd and is located in secondary
sensory areas embracing the primary hand representation (Wise et al.,
1997; Rizzolatti et al., 1998). Neuronal activity in these
interconnected areas correlates with both external and limb
coordinate spaces, subserving visuomotor transformations by reference
to an external, visuospatial reference frame (Boussaoud 1995; Johnson
et al., 1996; Shen and Alexander, 1997). Activation of this system in
the present study was bilateral, a finding consistent with studies on
explicit (Stephan et al., 1995) and implicit (Parsons et al., 1995)
motor imagery of the dominant hand.
In this dorsal system, area PMd has been suggested as the most probable
place where movement parameters from an allocentric, visuospatial
reference frame are transformed into limb-centered movement
descriptions (Kalaska and Crammond, 1992; Kalaska et al., 1997; Wise et
al., 1997). In our study, the analysis of limb-independent representations of movements revealed involvement of the anterior part
of the PMd only. A functional subdivision within the PMd of humans
(Deiber et al., 1991; Grafton et al., 1998) and nonhuman primates
(Johnson et al., 1996) has been suggested before, with activity in the
anterior part associated with target localization and selection or
preparation for movement and the posterior part with its execution. The
basis for this functional division is found in anatomical studies in
primates, where area 5 is interconnected predominantly with the primary
motor cortex and posterior PMd, whereas area MIP projects mainly to
anterior PMd (Strick and Kim, 1978; Ghosh and Gattera, 1995; Tanne et
al., 1995). This latter area has no direct projections to M1, and
indirectly only through posterior PMd (Barbas and Pandya, 1987). Our
study shows that movement parameters are coded in the system that
includes anterior PMd and MIP, which, like the ventral system, is part
of the anatomical hand representation, but functionally independent. In
these areas, a movement is coded for by a set of extrinsic kinematic
attributes. The posterior PMd, primary sensorimotor cortex, and
adjacent area 5 are hierarchically further "downstream", where
movement parameters code for the intrinsic kinematics of the executing
extremity. This explains why these areas, coding for the limb-specific
instructions, were not found in the analysis of limb-independent
movement representation.
The posterior part of the superior parietal cortex (Brodmann area 7),
which was activated by signing additionally to the zigzagging conditions, has been shown to play a role in the visual guidance of
movements, especially when retrieved from memory (Kawashima et al.,
1995), and lesions to this area cause disturbance of such functions
(Pause et al., 1989; Karnath, 1997). It is thought to code for a
multimodal, abstract representation of space (Andersen et al.,
1997).
Our data suggest that the functional representation of a highly trained
movement of the dominant hand is coded in neural assemblies that are
part of the anatomical representation of the limb with which it is
usually performed. Both the egocentric coordinate system (based on PMv)
and the allocentric reference frame (based on PMd) of the dominant hand
are engaged by the movement of signing, even when it is performed by
the toe. Movement parameters for an overlearned movement are therefore
stored independently from the executing extremity. The determinant for
somatotopy in sensorimotor structures other than primary cortex and
basal ganglia is not the limb with which a movement is actually
performed, but the limb with which it is habitually associated. These
areas constitute the intersection of anatomical and functional
representation in the human brain.
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FOOTNOTES |
Received Feb. 19, 1999; revised June 18, 1999; accepted June 30, 1999.
This work was supported in part by the Bundeministerium für
Bildung und Forschung (Bonn, Germany). C.B. and R.S.J.F. are supported
by the Wellcome Trust.
Correspondence should be addressed to Michel Rijntjes, Department of
Neurology, Friedrich Schiller University, Philosophenweg 3, 07740 Jena, Germany.
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REFERENCES |
-
Andersen RA,
Snyder LH,
Bradley DC,
Xing J
(1997)
Multimodal representation of space in the posterior parietal cortex and its use in planning movements.
Annu Rev Neurosci
20:303-330[ISI][Medline].
-
Barbas H,
Pandya DN
(1987)
Architecture and frontal cortical connections of the premotor cortex (area 6) in the rhesus monkey.
J Comp Neurol
256:211-228[ISI][Medline].
-
Boussaoud D
(1995)
Primate premotor cortex: modulation of preparatory neuronal activity by gaze angle.
J Neurophysiol
73:886-890[Abstract/Free Full Text].
-
Caminiti R,
Ferraina S,
Johnson PB
(1996)
The sources of visual information to the primate frontal lobe: a novel role for the superior parietal lobe.
Cereb Cortex
6:319-328[Abstract/Free Full Text].
-
Colby CL,
Duhamel JR,
Goldberg ME
(1993)
Ventral intraparietal area of the macaque: anatomic location and visual response properties.
J Neurophysiol
69:902-914[Abstract/Free Full Text].
-
Deiber MP,
Passingham RE,
Colbatch JG,
Friston KJ,
Nixon PD,
Frackowiak RSJ
(1991)
Cortical areas and the selection of movement: a study with positron emission tomography.
Exp Brain Res
84:393-402[ISI][Medline].
-
Fink GR,
Frackowiak RSJ,
Pietrzyk U,
Passingham R
(1997)
Multiple non-primary motor areas in the human cortex.
J Neurophysiol
67:1264-2174[Abstract/Free Full Text].
-
Fogassi L,
Gallese L,
Fadiga L,
Luppino G,
Matelli M,
Rizzolatti G
(1996)
Coding of peripersonal space in inferior premotor cortex (area F4).
J Neurophysiol
76:141-157[Abstract/Free Full Text].
-
Förster O
(1936)
The motor system in man in the light of Hughlings Jackson's doctrines.
Brain
59:135-159[Free Full Text].
-
Frackowiak RSJ,
Friston K,
Frith CD
(1997)
In: Human brain function. San Diego, CA: Academic.
-
Ghosh S,
Gattera R
(1995)
A comparison of the ipsilateral cortical projections to the dorsal and ventral subdivisions of the macaque premotor cortex.
Somatosens Mot Res
12:359-378[ISI][Medline].
-
Godschalk M,
Mitz AR,
van Duin B,
van den Burg H
(1995)
Somatotopy of monkey premotor cortex examined with microstimulation.
Neurosci Res
23:269-279[ISI][Medline].
-
Grafton ST,
Fagg AH,
Arbib MA
(1998)
Dorsal premotor cortex and conditional movement selection: a PET functional mapping study.
J Neurophysiol
79:1092-1097[Abstract/Free Full Text].
-
Graziano MS,
Hu XT,
Gross CG
(1997)
Visuospatial properties of ventral premotor cortex.
J Neurophysiol
77:2268-2292[Abstract/Free Full Text].
-
He S,
Dum R,
Strick P
(1993)
Topographic organization of corticospinal projections from the frontal lobe: motor areas on the lateral surface of the hemisphere.
J Neurosci
13:952-980[Abstract].
-
Jackson S,
Husain M
(1996)
Visuomotor functions of the lateral premotor cortex.
Curr Opin Neurobiol
6:788-795[ISI][Medline].
-
Johnson PB,
Ferraina S,
Bianchi L,
Caminiti R
(1996)
Cortical networks for visual reaching: physiological and anatomical organization of frontal and parietal lobe arm regions.
Cereb Cortex
6:102-119[Abstract/Free Full Text].
-
Kalaska JF,
Crammond DJ
(1992)
Cerebral cortical mechanisms of reaching movements.
Science
255:1517-1523[Abstract/Free Full Text].
-
Kalaska JF,
Scott SH,
Cisek P,
Sergio LE
(1997)
Cortical control of reaching movements.
Curr Opin Neurobiol
7:849-859[ISI][Medline].
-
Karnath HO
(1997)
Spatial orientation and the representation of space with parietal lobe lesions.
Philos Trans R Soc Lond B Biol Sci
352:1411-1419[ISI][Medline].
-
Kawashima R,
Roland PE,
O'Sullivan BT
(1995)
Functional anatomy of reaching and visuomotor learning: a positron emission tomography study.
Cereb Cortex
5:111-122[Abstract/Free Full Text].
-
Kurata K
(1989)
Distribution of neurons with set- and movement-related activity before hand and foot movements in the premotor cortex of rhesus monkeys.
Exp Brain Res
77:245-256[ISI][Medline].
-
Lashley K
(1930)
Basic neural mechanisms in behavior.
Psychol Rev
37:1-24.
-
Lehericy S,
van de Moortele PF,
Lobel E,
Paradis AL,
Vidailhet M,
Frouin V,
Neveu P,
Agid Y,
Marsault C,
Le Bihan D
(1998)
Somatotopical organization of striatal activation during finger and toe movement: a 3-T functional magnetic resonance imaging study.
Ann Neurol
44:398-404[ISI][Medline].
-
Matelli M,
Luppino G,
Rizzolatti G
(1985)
Pattern of cytochrome oxidase activity in frontal agranular cortex of the macaque monkey.
Behav Brain Res
18:125-136[ISI][Medline].
-
Matelli M,
Luppino A,
Murata A,
Sakata H
(1994)
Independent anatomical circuits for reaching and grasping linking inferior parietal lobule and inferior area 6 in the monkey.
Soc Neurosci Abstr
20:404.
-
Mesulam M-M
(1987)
Patterns in behavioral neuroanatomy: association areas, the limbic system, and hemispheric specialization.
In: Principles of behavioral neurology (Mesulam M-M,
ed), pp 1-70. Philadelphia: F.A. Davis.
-
Nitschke MF,
Keinschmidt A,
Wessel K,
Frahm J
(1996)
Somatotopic motor representation in the human anterior cerebellum. A high-resolution functional MRI study.
Brain
119:1023-1029[Abstract/Free Full Text].
-
Oldfield R
(1971)
The assessment and analysis of handedness: the Edinburgh inventory.
Neuropsychologia
9:97-113[ISI][Medline].
-
Parsons LM,
Fox PT,
Downs JH,
Glass T,
Hirsch TB,
Martin CC,
Jerabek PA,
Lancaster JL
(1995)
Use of implicit motor imagery for visual shape discrimination as revealed by PET.
Nature
375:54-58[Medline].
-
Passingham RE
(1989)
Premotor cortex and the retrieval of movement.
Brain Behav Evol
33:189-192[ISI][Medline].
-
Passingham RE
(1993)
In: The frontal lobes and voluntary action. Oxford: Oxford UP.
-
Pause M,
Kunesch E,
Binkofski F,
Freund HJ
(1989)
Sensorimotor disturbances in patients with lesions of the parietal cortex.
Brain
112:1599-1625[Abstract/Free Full Text].
-
Penfield W,
Boldrey E
(1938)
Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation.
Brain
15:389-443.
-
Price CJ,
Friston KJ
(1996)
Cognitive conjunction: a new approach to brain activation experiments.
NeuroImage
5:261-270.
-
Rizzolatti G,
Luppino G,
Matelli M
(1998)
The organization of the cortical motor system: new concepts.
Electroencephalogr Clin Neurophysiol
106:283-296[ISI][Medline].
-
Rosenbaum DA
(1991)
In: Human motor control. San Diego, CA: Academic.
-
Rothwell J
(1995)
In: Control of human voluntary movement. London: Chapman & Hall.
-
Sakata H,
Taira M
(1994)
Parietal control of hand action.
Curr Opin Neurobiol
4:847-856[Medline].
-
Sanes J,
Donoghue J
(1997)
Static and dynamic organization of motor cortex.
In: Brain plasticity (Freund HJ,
ed), pp 277-296. Philadelphia: Lippincott-Raven.
-
Sanes J,
Donoghue J,
Thangaraj V,
Edelman R,
Warach S
(1995)
Shared neural substrates controlling hand movements in human motor cortex.
Science
268:1775-1777[Abstract/Free Full Text].
-
Schieber M,
Hibbard L
(1993)
How somatotopic is the motor cortex hand area?
Science
261:489-492[Abstract/Free Full Text].
-
Shen L,
Alexander GE
(1997)
Preferential representation of instructed target location versus limb trajectory on dorsal premotor cortex.
J Neurophysiol
77:1195-1212[Abstract/Free Full Text].
-
Soechting JF,
Flanders M
(1989)
Sensorimotor representations for pointing to targets in three-dimensional space.
J Neurophysiol
62:582-594[Abstract/Free Full Text].
-
Stephan KM,
Fink GR,
Passingham RE,
Silbersweig D,
Ceballos-Baumann AO,
Frith CD,
Frackowiak RSJ
(1995)
Functional anatomy of the mental representation of upper extremity movements in healthy subjects.
J Neurophysiol
73:373-386[Abstract/Free Full Text].
-
Strick PL,
Kim CC
(1978)
Input to primate motor cortex from posterior parietal cortex (area 5). 1. Demonstration by retrograde transport.
Brain Res
157:325-330[ISI][Medline].
-
Tanne J,
Boussaoud D,
Boyer-Zeller N,
Rouiller E
(1995)
Parietal inputs to physiologically defined regions of dorsal premotor cortex in the macaque monkey.
Eur J Neurosci
8:195-201.
-
Tootell RBH,
Reppas JB,
Dale AM,
Look RB,
Sereno MI,
Malach R,
Brady TJ,
Rosen BR
(1995)
Visual motion aftereffect in human cortical area MT revealed by functional magnetic resonance imaging.
Nature
375:139-141[Medline].
-
Watson JDG,
Myers R,
Frackowiak RSJ,
Hajnal JV,
Woods RP,
Mazziotta JC,
Shipp S,
Zeki S
(1993)
Area V5 of the human brain: evidence from a combined study using positron emission tomography and magnetic resonance imaging.
Cereb Cortex
3:79-94[Abstract/Free Full Text].
-
Wise SP,
Boussaoud D,
Johnson PB,
Caminiti R
(1997)
Premotor and parietal cortex: corticocortical connectivity and combinatorial computations.
Annu Rev Neurosci
20:25-42[ISI][Medline].
-
Wolpert DM,
Ghahramani Z,
Jordan MI
(1995)
Are arm trajectories planned in kinematic or dynamic coordinates? An adaptation study.
Exp Brain Res
103:460-470[ISI][Medline].
Copyright © 1999 Society for Neuroscience 0270-6474/99/19188043-06$05.00/0
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TOP
ABSTRACT
INTRODUCTION
