Remarkable advances have recently been made in the development of Brain-Machine Interface (BMI) technologies for restoring or enhancing motor function. However, the application of these technologies ...may be limited to patients in static conditions, as these developments have been largely based on studies of animals (e.g., non-human primates) in constrained movement conditions. The ultimate goal of BMI technology is to enable individuals to move their bodies naturally or control external devices without physical constraints. Here, we demonstrate accurate decoding of muscle activity from electrocorticogram (ECoG) signals in unrestrained, freely behaving monkeys. We recorded ECoG signals from the sensorimotor cortex as well as electromyogram signals from multiple muscles in the upper arm while monkeys performed two types of movements with no physical restraints, as follows: forced forelimb movement (lever-pull task) and natural whole-body movement (free movement within the cage). As in previous reports using restrained monkeys, we confirmed that muscle activity during forced forelimb movement was accurately predicted from simultaneously recorded ECoG data. More importantly, we demonstrated that accurate prediction of muscle activity from ECoG data was possible in monkeys performing natural whole-body movement. We found that high-gamma activity in the primary motor cortex primarily contributed to the prediction of muscle activity during natural whole-body movement as well as forced forelimb movement. In contrast, the contribution of high-gamma activity in the premotor and primary somatosensory cortices was significantly larger during natural whole-body movement. Thus, activity in a larger area of the sensorimotor cortex was needed to predict muscle activity during natural whole-body movement. Furthermore, decoding models obtained from forced forelimb movement could not be generalized to natural whole-body movement, which suggests that decoders should be built individually and according to different behavior types. These results contribute to the future application of BMI systems in unrestrained individuals.
To precisely understand how higher cognitive functions are implemented in the prefrontal network of the brain, optogenetic and pharmacogenetic methods to manipulate the signal transmission of a ...specific neural pathway are required. The application of these methods, however, has been mostly restricted to animals other than the primate, which is the best animal model to investigate higher cognitive functions. In this study, we used a double viral vector infection method in the prefrontal network of the macaque brain. This enabled us to express specific constructs into specific neurons that constitute a target pathway without use of germline genetic manipulation. The double-infection technique utilizes two different virus vectors in two monosynaptically connected areas. One is a vector which can locally infect cell bodies of projection neurons (local vector) and the other can retrogradely infect from axon terminals of the same projection neurons (retrograde vector). The retrograde vector incorporates the sequence which encodes Cre recombinase and the local vector incorporates the "Cre-On" FLEX double-floxed sequence in which a reporter protein (mCherry) was encoded. mCherry thus came to be expressed only in doubly infected projection neurons with these vectors. We applied this method to two macaque monkeys and targeted two different pathways in the prefrontal network: The pathway from the lateral prefrontal cortex to the caudate nucleus and the pathway from the lateral prefrontal cortex to the frontal eye field. As a result, mCherry-positive cells were observed in the lateral prefrontal cortex in all of the four injected hemispheres, indicating that the double virus vector transfection is workable in the prefrontal network of the macaque brain.
A quantitative evaluation of motility is crucial for studies employing experimental animals. Here, we describe the development of an in-cage motility monitoring method for new world monkeys using ...off-the-shelf components, and demonstrate its capability for long-term operation (e.g., a year). Based on this novel system, we characterized the motility of the common marmoset over different time scales (seconds, hours, days, and weeks). Monitoring of seven young animals belonging to two different age groups (sub-adult and young-adult) over a 231-day period revealed: (1) strictly diurnal activity (97.3% of movement during daytime), (2) short-cycle (∼20 s) transition in activity, and (3) bimodal diurnal activity including a "siesta" break. Additionally, while the mean duration of short-cycle activity, net daily activity, and diurnal activity changed over the course of development, 24-h periodicity remained constant. Finally, the method allowed for detection of progressive motility deterioration in a transgenic marmoset. Motility measurement offers a convenient way to characterize developmental and pathological changes in animals, as well as an economical and labor-free means for long-term evaluation in a wide range of basic and translational studies.
The purpose of this study is to examine the abdominal X-ray image contrast with additional Cu filtration using Scheffé’s paired comparison method. We obtained abdominal phantom images with different ...Cu filter thickness after dynamic processing. We measured the image contrast of abdominal phantom images and evaluated them using Scheffé’s paired comparison method. The observers were 7 radiological technologists (2 to 33 years of experience, average 15.6 years). Approximately, there was a maximum of 16 % decreasement in the image contrast when we added 0.3 mm Cu filtration. There was no significant difference in Scheffé’s paired comparison method (95 % confidence interval) . From these results, abdominal X-ray with up to 0.3 mm Cu filtration does not decrease visually significant image contrast. Abdominal X-ray with up to 0.3 mm Cu filtration does not decrease visually image contrast.
1 Department of Neurology, University of
Tokyo School of Medicine, Tokyo 113-8655;
2 Department of Physiology, Juntendo
University School of Medicine, Tokyo 113-0033; and
3 Brain Science ...Research Center, Tamagawa
University Research Institute, Tokyo 194-8610, Japan
Kobayashi, Shunsuke,
Johan Lauwereyns,
Masashi Koizumi,
Masamichi Sakagami, and
Okihide Hikosaka.
Influence of Reward Expectation on Visuospatial Processing in
Macaque Lateral Prefrontal Cortex. J. Neurophysiol. 87: 1488-1498, 2002. The lateral prefrontal cortex (LPFC)
has been implicated in visuospatial processing, especially when it is
required to hold spatial information during a delay period. It has also
been reported that the LPFC receives information about expected reward
outcome. However, the interaction between visuospatial processing and
reward processing is still unclear because the two types of processing could not be dissociated in conventional delayed response tasks. To
examine this, we used a memory-guided saccade task with an asymmetric
reward schedule and recorded 228 LPFC neurons. The position of the
target cue indicated the spatial location for the following saccade and
the color of the target cue indicated the reward outcome for a correct
saccade. Activity of LPFC was classified into three main types: S-type
activity carried only spatial signals, R-type activity carried only
reward signals, and SR-type activity carried both. Therefore only
SR-type cells were potentially involved in both visuospatial processing
and reward processing. SR-type activity was enhanced (SR+) or depressed (SR ) by the reward expectation. The spatial discriminability as
expressed by the transmitted information was improved by reward expectation in SR+ type. In contrast, when reward information was coded
by an increase of activity in the reward-absent condition (SR type),
it did not improve the spatial representation. This activity appeared
to be involved in gaze fixation. These results extend previous findings
suggesting that the LPFC exerts dual influences based on predicted
reward outcome: improvement of memory-guided saccades (when reward is
expected) and suppression of inappropriate behavior (when reward is not expected).
We devised a split-bolus injection and imaging protocol for pulmonary artery and vein separation computed tomography (CT) angiography based on time enhancement curve characterization. Furthermore, we ...aimed to evaluate the contrast enhancement effect and success rate of blood vessel separation between the pulmonary artery and vein of this proposed protocol.
In this study, 102 patients (45 patients with the standard protocol and 57 patients with the proposed protocol) who underwent pulmonary arteriovenous computed tomography angiography were included. The CT values of various vessels, CT value difference between the pulmonary trunk and left atrium, and coefficient of variation in pulmonary arteries and veins were obtained from images of the standard and proposed protocols.
The CT values in the proposed protocol for the pulmonary trunk were significantly higher than those in the standard protocol (487.3 415.5-546.9 HU vs. 293.0 259.0-350.0 HU, P < 0.01). The CT value difference between the pulmonary trunk and left atrium in the proposed protocol was significantly higher than that in the conventional protocol (211.3 158.0-265.7 HU vs. 32 -30.0-55.0 HU, P < 0.01). The coefficient of variation in the proposed protocol was 0.08 (0.06-0.10) and 0.09 (0.08-0.11) in pulmonary arteries and 0.08 (0.06-0.09) and 0.09 (0.07-0.12) in pulmonary veins, respectively.
The proposed protocol achieved separation between the pulmonary artery and vein in many patients, making it useful for the preoperative assessment of individual thoracic anatomy.
Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer RF-(DOBAA) ₙ -RF reacted with tetraethoxysilane (TEOS) and silica nanoparticles in the presence of low-molecular weight biocides ...such as hibitane, hinokitiol, and hinokioil under alkaline conditions to afford RF-(DOBAA) ₙ -RF/silica nanocomposites-encapsulated these biocides in excellent to moderate isolated yields. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer RF-(DMAA) ₙ -RF and acrylic acid oligomer RF-(ACA) ₙ -RF/silica nanocomposites-encapsulated hibitane were obtained under similar conditions. Dynamic light scattering measurements showed that the size of these fluorinated nanocomposites-encapsulated biocides thus obtained is nanometer size-controlled. Additionally, these fluorinated nanocomposites were shown to have a good dispersibility and stability in methanol and water. Of particular interest, these fluorinated nanocomposites-encapsulated biocides were found to have a good antibacterial activity against Staphylococcus aureus, and these nanocomposites were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate).
This study assessed the feasibility of using three-dimensional (3D) models of intrapelvic vascular patterns constructed using computed tomography (CT) and magnetic resonance imaging (MRI) fusion data ...for preoperative planning in patients with locally recurrent rectal cancer.
Eleven patients scheduled for pelvic exenteration were included. The 3D fusion data of the intrapelvic vessels constructed using CT and MRI with true fast imaging with steady-state precession sequence (True FISP) were evaluated preoperatively. Contrast ratios (CR) between the piriformis muscle and the intrapelvic vessels were calculated to identify a valid modality for 3D modeling and creating CT/MRI fusion-reconstructed volume-rendered images.
The CR values of the internal and external iliac arteries were significantly higher on CT images than MR images (CT vs. MRI; 0.63 vs. 0.45, p < 0.01). However, the CR value of the internal iliac vein was significantly higher on MR than CT images (CT vs. MRI; 0.23 vs. 0.55, p < 0.01).
MRI with True FISP yielded high signal-to-noise ratios and aided in delineating the internal iliac vein around the piriformis muscle. More precise 3D models can be constructed using this technique in the future to aid in the resection of locally recurrent rectal cancer.
Display omitted
•MRI with True FISP is superior to what internal iliac vein delineation.•MRI with True FISP yielded high contrast ratios between internal iliac vein and piriformis muscle.•CT/MRI fusion is suitable for preoperative planning for locally recurrent rectal cancer.
1 Department of Physiology, Juntendo
University, Tokyo 113-0033; 2 Brain Science
Research Center, Tamagawa University, Tokyo 194-8610;
3 Department of Physiology, Nihon University,
Tokyo ...173-8610; and 4 Department of
Neurology, University of Tokyo, Tokyo 113-8655, Japan
Lauwereyns, Johan,
Masamichi Sakagami,
Ken-Ichiro Tsutsui,
Shunsuke Kobayashi,
Masashi Koizumi, and
Okihide Hikosaka.
Responses to Task-Irrelevant Visual Features by Primate
Prefrontal Neurons. J. Neurophysiol. 86: 2001-2010, 2001. The primate brain is
equipped with prefrontal circuits for interpreting visual information,
but how these circuits deal with competing stimulus-response (S-R)
associations remains unknown. Here we show different types of responses
to task-irrelevant visual features in three functionally dissociated
groups of primate prefrontal neurons. Two Japanese macaques
participated in a go/no-go task in which they had to discriminate
either the color or the motion direction of a visual target to make a
correct manual response. Prior to the experiment, the monkeys had been
trained extensively so that they acquired fixed associations between
visual features and required responses (e.g., "green = go";
"downward motion = no-go"). In this design, the monkey was
confronted with a visual target from which it had to extract relevant
information (e.g., color in the color-discrimination condition) while
ignoring irrelevant information (e.g., motion direction in the
color-discrimination condition). We recorded from 436 task-related
prefrontal neurons while the monkey performed the multidimensional
go/no-go task: 139 (32%) neurons showed go/no-go discrimination based
on color as well as motion direction ("integration cells"); 192 neurons (44%) showed go/no-go discrimination only based on color
("color-feature cells"); and 105 neurons (24%) showed go/no-go
discrimination only based on motion direction ("motion-feature
cells"). Overall, however, 162 neurons (37%) were influenced by
irrelevant information: 53 neurons (38%) among integration cells, 71 neurons (37%) among color-feature cells, and 38 neurons (36%) among
motion-feature cells. Across all types of neurons, the response to an
irrelevant feature was positively correlated with the response to the
same feature when it was relevant, indicating that the influence from irrelevant information is a residual from S-R associations that are
relevant in a different context. Temporal and anatomical differences among integration, color-feature and motion-feature cells suggested a
sequential mode of information processing in prefrontal cortex, with
integration cells situated toward the output of the decision-making process. In these cells, the response to irrelevant information appears
as a congruency effect, with better go/no-go discrimination when both
the relevant and irrelevant feature are associated with the same
response than when they are associated with different responses. This
congruency effect could be the result of the combined input from color-
and motion-feature cells. Thus these data suggest that irrelevant
features lead to partial activation of neurons even toward the output
of the decision-making process in primate prefrontal cortex.
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