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Activation of the claustrum in connection with putamen and globus pallidus activity studied by fMRI
ABSTRACTS
Activation of the Claustrum in Connection with Putamen and Globus Pallidus Activity Studied by fMRI V.H. Scholz*t, B.G. Jenkins*, J.R. Keltner*, Y.I. Chen*, K.K. Kwong* and B.R. Rosen* *Mas~sachusetts General Hospital NMR Center, Dept. of Radiology, Charlestown, MA 02129 TIInstitut fiir R6ntgendiagnostik, Charitd, Humboldt- Universitdt zu Berlin, Germany Introduction .- The claustrum is a thin structure of gray matter located between the insula and putamen. It is separated
from the putamen by the external capsule and from the insula by the extreme capsule. It is regarded as belonging to the corpus striatum (1). The claustrum receives major projections from primary visual cortex, the auditory cortex and somatosensory cortical fields and contains retinotopic and somatotopic representations (1,2). The claustrum is connected to the motor cortex ipsilaterally and contralaterally, the basal ganglia, thalamus and projects to the midbrain (3). Particularly, the presence of reciprocal connections between the visual pathway on the one hand and motor system on the other hand suggests that the claustrum has a potential role to play in the development of the photosensitive motor response. We observed fMRI-activity by implementing different motor tasks to study the basal ganglia. In particular claustrum activation was observed in the eyemovement and writing tasks. _Methods - T a s k s : 1.Signing the name continuously while looking at the paper and watching the signing. 2.Self-
paced saccadic eye movements. 3.Cued finger tapping. 4.Switching of hand and foot movements. 5.Supination/Pronation of the forearm. All tasks except saccadic eye movements were studied separately on the right, left and on both sides. Baseline was no movement in all studies. The activation periods alternated between 30 secs off and on. Subjects: Between ten to 25 studies for each task were performed in volunteers. I m a g i n g : Gradient Echo EPI images (GE 1.5T Signa MR unit with an echo-planar retrofit by Advanced NMR (Woburn, MA)) were collected in an oblique/coronal orientation covering the basal ganglia and the motor cortex. A standard quadrature head coil was used. Imaging parameters were: TR/TE= 2400/45 ms, ~=75~ ~ 8-10 7mm slices with no gap, FOV=40x20cm, matrix size=128x64. 180 to 200 images were collected over a 6-7 min period consisting of 6 to 8 epochs of 30 seconds of activation alternating with 30 seconds of baseline. High resolution Tl-weighted images were acquired for anatomical location. Analysis: All data sets were motion corrected [4]. Statistical maps were generated using KS-statistics. We performed automated segmentation analysis of the statistical maps (p <0.05 adjusted for the number of pixels and clustering of at least four to be considered real) to determine activation in the claustrum by projecting the statistical map on the Tl-weighted image. R e s u l t s - As shown in Table 1 writing and eyemovements showed claustrum activation as well as putamen and
globus pallidus activation. This is in contrast to finger tapping, supination/pronation and switching which did not activate the claustrum but would activate the globus pallidus, putamen, motor cortex, thalamus. In addition auditory cortex was activated when tasks were cued. writing
n~o. of studies claustrum put./globus pallidus nucl.caudatus
19 3 13 8I
eyemovements finger tapping switiching sup./pronatior 8 26 20 16
4
0
0
1
7
18
18
10
2
11
4
0
T a b . l : Location of activation of the different tasks.
F i g . 1: Fig.la shows activity in the claustrum of both hemispheres during a writing task in contrast to. Fig.lb which shows activation in the putamen and globus pallidus of the left hemisphere during a switching task.
D i s c u s s i o n - While the function of the claustrum has troubled investigators for decades, our results show that it is possible to see fMRI-activity in the claustrum, globus pallidus and putamen during motor tasks that involve the visual system like writing and eyemovements. As there are not nearly the density of large vessels in the basal ganglia or claustrum as there are in motor cortex the functional signal may be directly related to neuronal activity. While the entire function of the claustrum is not clear fMRI seems to be a good potential tool to study complex neural circuits. R e f e r e n c e s : l . Carey, R.G. and Neal, T.L. Brain Res., 386: 155-168, (1986). 2. Clarey, J.C. and Irvine, D.R. Exp.Brain Res., 61: 432-437, (1986). 3. Crescimanno, G. and Salerno, M.T., et.all., Brain Res. Bull., 22: 839-843, (1989). 4. Jiang et al. (1994) SMRM, 1:351.
$411
Activation of the Claustrum in Connection with Putamen and Globus Pallidus Activity Studied by fMRI V.H. Scholz*t, B.G. Jenkins*, J.R. Keltner*, Y.I. Chen*, K.K. Kwong* and B.R. Rosen* *Mas~sachusetts General Hospital NMR Center, Dept. of Radiology, Charlestown, MA 02129 TIInstitut fiir R6ntgendiagnostik, Charitd, Humboldt- Universitdt zu Berlin, Germany Introduction .- The claustrum is a thin structure of gray matter located between the insula and putamen. It is separated
from the putamen by the external capsule and from the insula by the extreme capsule. It is regarded as belonging to the corpus striatum (1). The claustrum receives major projections from primary visual cortex, the auditory cortex and somatosensory cortical fields and contains retinotopic and somatotopic representations (1,2). The claustrum is connected to the motor cortex ipsilaterally and contralaterally, the basal ganglia, thalamus and projects to the midbrain (3). Particularly, the presence of reciprocal connections between the visual pathway on the one hand and motor system on the other hand suggests that the claustrum has a potential role to play in the development of the photosensitive motor response. We observed fMRI-activity by implementing different motor tasks to study the basal ganglia. In particular claustrum activation was observed in the eyemovement and writing tasks. _Methods - T a s k s : 1.Signing the name continuously while looking at the paper and watching the signing. 2.Self-
paced saccadic eye movements. 3.Cued finger tapping. 4.Switching of hand and foot movements. 5.Supination/Pronation of the forearm. All tasks except saccadic eye movements were studied separately on the right, left and on both sides. Baseline was no movement in all studies. The activation periods alternated between 30 secs off and on. Subjects: Between ten to 25 studies for each task were performed in volunteers. I m a g i n g : Gradient Echo EPI images (GE 1.5T Signa MR unit with an echo-planar retrofit by Advanced NMR (Woburn, MA)) were collected in an oblique/coronal orientation covering the basal ganglia and the motor cortex. A standard quadrature head coil was used. Imaging parameters were: TR/TE= 2400/45 ms, ~=75~ ~ 8-10 7mm slices with no gap, FOV=40x20cm, matrix size=128x64. 180 to 200 images were collected over a 6-7 min period consisting of 6 to 8 epochs of 30 seconds of activation alternating with 30 seconds of baseline. High resolution Tl-weighted images were acquired for anatomical location. Analysis: All data sets were motion corrected [4]. Statistical maps were generated using KS-statistics. We performed automated segmentation analysis of the statistical maps (p <0.05 adjusted for the number of pixels and clustering of at least four to be considered real) to determine activation in the claustrum by projecting the statistical map on the Tl-weighted image. R e s u l t s - As shown in Table 1 writing and eyemovements showed claustrum activation as well as putamen and
globus pallidus activation. This is in contrast to finger tapping, supination/pronation and switching which did not activate the claustrum but would activate the globus pallidus, putamen, motor cortex, thalamus. In addition auditory cortex was activated when tasks were cued. writing
n~o. of studies claustrum put./globus pallidus nucl.caudatus
19 3 13 8I
eyemovements finger tapping switiching sup./pronatior 8 26 20 16
4
0
0
1
7
18
18
10
2
11
4
0
T a b . l : Location of activation of the different tasks.
F i g . 1: Fig.la shows activity in the claustrum of both hemispheres during a writing task in contrast to. Fig.lb which shows activation in the putamen and globus pallidus of the left hemisphere during a switching task.
D i s c u s s i o n - While the function of the claustrum has troubled investigators for decades, our results show that it is possible to see fMRI-activity in the claustrum, globus pallidus and putamen during motor tasks that involve the visual system like writing and eyemovements. As there are not nearly the density of large vessels in the basal ganglia or claustrum as there are in motor cortex the functional signal may be directly related to neuronal activity. While the entire function of the claustrum is not clear fMRI seems to be a good potential tool to study complex neural circuits. R e f e r e n c e s : l . Carey, R.G. and Neal, T.L. Brain Res., 386: 155-168, (1986). 2. Clarey, J.C. and Irvine, D.R. Exp.Brain Res., 61: 432-437, (1986). 3. Crescimanno, G. and Salerno, M.T., et.all., Brain Res. Bull., 22: 839-843, (1989). 4. Jiang et al. (1994) SMRM, 1:351.
$411