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Context: Toe direction is an important factor affecting knee biomechanics during various movements. However, it is still unknown whether toe direction will affect trunk and pelvic movements., Objective: To examine and clarify the effects of toe directions on biomechanics of trunk and pelvis as well as lower-extremities during single-leg drop landing (SLDL)., Design: Descriptive laboratory study., Setting: Research laboratory., Participants: A total of 27 male recreational-level athletes., Intervention(s): Subjects performed SLDL under 3 different toe directions, including 0° (toe neutral), 20° (toe-in [TI]), and -20° (toe-out). SLDL was captured using a motion analysis system. Nondominant leg (27 left) was chosen for the analysis., Main Outcome Measures: Peak values of kinematic and kinetic parameters during landing phase were assessed. In addition, those parameters at the timing of peak vertical ground reaction force were also assessed. The data were statistically compared among 3 different toe directions using 1-way repeated measures of analysis of variance or Friedman χ2 r test., Results: Peak knee abduction angle and moment in TI were significantly larger than in toe neutral and toe-out (P < .001). Moreover, peak greater anterior inclination, greater inclination, and rotation of trunk and pelvis toward the nonlanding side were seen in TI (P < .001). At the timing of peak vertical ground reaction force, trunk inclined to the landing side with larger knee abduction angle in TI (P < .001)., Conclusions: Several previous studies suggested that larger knee abduction angle and moment on landing side as well as trunk and pelvic inclinations during landing tasks were correlated with knee ligament injury. However, it is still unknown concerning the relationship between toe direction and trunk/pelvis movements during landing tasks. From the present study, TI during SLDL would strongly affect biomechanics of trunk and pelvis as well as knee joint, compared with toe neutral and toe-out.

The aim of the study was to assess the validity and reliability of using the Portapres ® to measure toe blood pressure during rest and exercise. Construct validity, concurrent validity, and interday reliability were assessed by measuring toe (Portapres ®) ) and brachial blood pressure in 16 nondisabled participants on consecutive days. Construct validity was assessed by pedaling on a cycle ergometer (6 revolutions per minute) and comparing the measured toe blood pressure to an estimated value based on orthostatic factors. Concurrent validity was assessed by comparing toe and brachial blood pressure during supine rest and following 10 min of cycling exercise. Interday reliability was assessed by recording toe and brachial blood pressure during supine rest on a second day. Construct validity analysis shows that the toe blood pressure signal was moderately correlated with the changes in heart-toe distance and that changes in toe blood pressure during slow cycling were similar to the estimated value. Resting toe and brachial mean arterial blood pressure showed concurrent validity with only a fixed bias explained by the change in orthostatic pressure and the toe-brachial index. Furthermore, cycling exercise was associated with an increase in brachial and a decrease in toe mean blood pressure. The interday reliability analysis showed no proportional or fixed bias for mean arterial blood pressure. Our study showed the feasibility of using the Portapres ® to measure toe blood pressure during movement and can be used to study the effect of movement-related forces during cycling on toe blood pressure., (© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Magnetoencephalographic (MEG) signals recorded from the primary sensorimotor (SM1) cortex are coherent with kinematics of both active and passive finger movements. The coherence mainly reflects movement-related proprioceptive afference to the cortex. Here we describe a novel MEG-compatible stimulator to generate computer-controlled passive finger and toe movements that can be used as stimuli in functional brain-imaging experiments. The movements are produced by pneumatic artificial muscle (PAM), elastic actuator that shortens with increasing air pressure. To test the applicability of the stimulator to functional brain-imaging, 4-min trains of passive repetitive 5-mm flexion-extension movements of the right and left index finger and the right hallux were produced at 3Hz while the subject's brain activity was measured with whole-scalp MEG and finger or toe kinematics with an accelerometer. In all ten subjects studied, statistically significant coherence (up to 0.78) occurred between the accelerometer and MEG signals at the movement frequency or its first harmonic. Sources of coherent activity were in the contralateral hand or foot SM1 cortices. Movement-evoked fields elicited with intermittent movements of the right index finger (once every 3.2-4.0s; mean±SD peak response latency 88±25ms) were co-located with the respective coherent sources. We further moved the right index finger at 3, 6, and 12Hz (movement ranges 5, 3, and 2mm, respectively), and analyzed the first 1, 2, and 4-min epochs of data. One minute of data was sufficient to locate the left hand area of the SM1 cortex at all movement frequencies. Sound-induced spurious coherence was reliably ruled out in a control experiment. Our novel movement stimulator thus provides a robust and reliable tool to track proprioceptive afference to the cortex and to locate the SM1 cortex., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to examine the effect of changing toe direction on knee kinetics and kinematics associated with anterior cruciate ligament injury during drop vertical jumps., Methods: Fourteen females performed drop vertical jumps under three toe conditions (natural, toe-in, and toe-out). The knee kinetics and kinematics during landing were evaluated using a motion analysis system. Results under three toe conditions were compared using a one-way repeated measures analysis of variance and a post hoc Bonferroni test., Results: Toe-in landing was associated with a significantly greater knee abduction angle, tibial internal rotation angle, and knee abduction moment than the natural and toe-out conditions. Toe-out landing was associated with significantly greater tibial internal rotational angular velocity., Conclusions: Changing toe direction significantly affects knee kinetics and kinematics during landing. It is important to avoid changing toe direction excessively inward or outward during landing to prevent the increases in knee abduction and tibial internal rotation which might increase the risk of ACL injury., Level of Evidence: Prognosis, Level IV.

It is well-known that physical exercise can affect cognition and the frontal lobe is an important structure involved in motor function and cognition. Furthermore, many functional neuroimaging studies have demonstrated that cortical activation patterns of hand and leg movements differ. However, no study has been undertaken to identify differences between the frontal activation patterns generated by hand and leg movements. In the present study, the frontal activation patterns associated with finger and toe movements, as visualized by functional MRI, were investigated and compared. Twelve healthy volunteers were recruited. Functional MRI was performed using a 1.5 T Philips Gyroscan Intera. Flexion-extension movements of fingers or toes were performed in one extremity. Regions of interest (ROIs) were set at the primary sensory-motor cortex (SM1: Brodmann area [BA] 1, 2, 3, 4), the premotor area (PMA: BA 6), and the prefrontal cortex (PFC: BA 8, 9, 10, 11, 46). In SM1, finger movements (10,809) induced more activation than toe movements (5349). On the other hand, in the PMA and PFC, toe movements (PMA: 4201, PFC: 921) induced more activation than finger movements (PMA: 2887, PFC: 912) respectively. In the analysis of relative voxel counts in the PMA and PFC versus the SM1, toe movements generated more activation in the PMA and PFC than finger movements. The PMA and PFC were more activated by toe than finger movements, although the SM1 was more activated by finger movements., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

The metatarsal phalangeal joint (MPJ) and its crossing toe flexor muscles (TFM) represent the link between the large energy generating leg extensor muscles and the ground. The purpose of this study was to examine the functional adaptability of TFM to increased mechanical stimuli and the effects on walking, running and jumping performance. Fifteen men performed a heavy resistance TFM strength training with 90% of the maximal voluntary isometric contraction (MVIC) for 7 weeks (560 contractions) for the left and right foot. Maximal MPJ and ankle plantar flexion moments during MVICs were measured in dynamometers before and after the intervention. Motion analyses (inverse dynamics) were performed during barefoot walking, running, and vertical and horizontal jumping. Athletic performance was determined by measuring jump height and distance. Left (0.21 to 0.38 Nm · kg(-1); P < 0.001) and right (0.24 to 0.40 Nm · kg(-1); P < 0.001) MPJ plantar flexion moments in the dynamometer, external MPJ dorsiflexion moments (0.69 to 0.75 Nm · kg(-1); P = 0.012) and jump distance (2.25 to 2.31 m; P = 0.006) in horizontal jumping increased significantly. TFM responded highly to increased loading within a few weeks. The increased force potential made a contribution to an athlete's performance enhancement.

Periodic Limb Movements during Sleep (PLMS) can cause significant disturbance to sleep, resulting in daytime sleepiness and reduced quality of life. In conventional clinical practice, PLMS are measured using overnight electromyogram (EMG) of the tibialis anterior muscle, although historically they have also been measured using piezo-electric gauges placed over the muscle. However, PLMS counts (PLM index) do not correlate well with clinical symptomology. In this study, we propose that because EMG and piezo derived signals measure muscle activation rather than actual movement, they may count events with no appreciable movement of the limb and therefore no contribution to sleep disturbance. The aim of this study is thus to determine the percentage of clinically scored limb movements which are not associated with movement of the great toe measured using accelerometry. 9 participants were studied simultaneously with an overnight diagnostic polysomnogram (including EMG and piezo instrumentation of the right leg) and high temporal resolution accelerometry of the right great toe. Limb movements were scored, and peak acceleration during each scored movement was quantified. Across the participant population, 54.9% (range: 26.7-76.3) and 39.0% (range: 4.8-69.6) of limb movements scored using piezo and EMG instrumentation respectively, were not associated with toe movement measured with accelerometry. If sleep disturbance is the consequence of the limb movements, these results may explain why conventional piezo or EMG derived PLMI is poorly correlated with clinical symptomology.

A concept emerging from recent studies on obstacle avoidance in quadrupeds is that working memory of the height of an obstacle established by visual information is enhanced by motor interactions with the obstacle. In this investigation, we found that this concept is valid in adult humans when viewing and walking up stairs. The main finding was that the memory of the height of stairs was enhanced when information about stair height was gained by walking up a short flight of stairs compared to when information about stair height was gained by vision alone. By measuring the maximum toe clearance when subjects step onto a stair, we observed that maximum toe clearance increased after diverting vision from the stair for a few seconds prior to stepping. Most of this increase occurred within a 2-s period between diverting vision from the stair and initiating the step. By contrast, this increase in maximum toe clearance after diverting vision from a stair was significantly reduced after subjects walked up two stairs prior to stepping onto a stair without vision. This reduction persisted for delays as long as 10 s between diverting vision from the stair and initiating the step. In four of twelve subjects, the maximum toe clearance after these long periods without vision of the stair was close to the value when steps were made with full vision of the stairs.

Foot and toe clearance (TC) are used regularly to describe locomotor control for both clinical and basic research. However, accuracy of TC during obstacle crossing can be compromised by typical sample frequencies, which do not capture the frame when the foot is over the obstacle due to high limb velocities. The purpose of this study was to decrease the error of TC measures by increasing the spatial resolution of the toe trajectory with interpolation. Five young subjects stepped over an obstacle in the middle of an 8 m walkway. Position data were captured at 600 Hz as a gold standard signal (GS-600-Hz). The GS-600-Hz signal was downsampled to 60 Hz (DS-60-Hz). The DS-60-Hz was then interpolated by either upsampling or an algorithm. Error was calculated as the absolute difference in TC between GS-600-Hz and each of the remaining signals, for both the leading limb and the trailing limb. All interpolation methods reduced the TC error to a similar extent. Interpolation reduced the median error of trail TC from 5.4 to 1.1 mm; the maximum error was reduced from 23.4 to 4.2 mm (16.6-3.8%). The median lead TC error improved from 1.6 to 0.5 mm, and the maximum error improved from 9.1 to 1.8 mm (5.3-0.9%). Therefore, interpolating a 60 Hz signal is a valid technique to decrease the error of TC during obstacle crossing., (Published by Elsevier Ltd.)

The corticospinal tract (CST) is the most important motor tract in the human brain. The authors compared CST fibers of the fingers and toes using diffusion tensor imaging. Eleven normal healthy subjects were recruited for this study. Functional MRI stimulation was performed using finger grasp-release movements and toe flexion-extension movements (1 Hz). CST fibers of the fingers and toes were determined by selecting fibers passing through seed (the CST portion in the pons) and target regions of interest (the activation areas of the cerebral cortex during active finger and toe movements, respectively). No significant differences were observed between CST fibers of the fingers and toes in terms of fractional anisotropy, mean diffusivity, or tract volume (P> 0.05), and no differences were observed between the connectivities of CST fibers of the fingers and toes and the dorsal premotor cortex or the supplementary motor area (P>0.05). However, the connectivities between CST fibers of legs and the contralateral primary motor cortex were greater than those of CST fibers of the fingers (P< 0.05). It was found that somatotopic CST fibers of the fingers and toes did not differ in terms of diffusion tensor imaging characteristics, but that transcallosal fibers to the contralateral motor cortex were more frequent for CST fibers of the toes than for CST fibers of the fingers.

To investigate whether conscious judgments of movement onset are based solely on pre-movement signals (i.e., premotor or efference copy signals) or whether sensory feedback (i.e., reafferent) signals also play a role, participants judged the onset of finger and toe movements that were either active (i.e., self initiated) or passive (i.e., initiated by the experimenter). Conscious judgments were made by reporting the position of a rotating clock hand presented on a computer screen and were then compared to the actual measured time of movement onset. In line with previous studies, judgment errors were found to be anticipatory for both finger and toe movements. There was a significant difference between judgment errors for active and passive movements, with judgments of active movements being more anticipatory than judgments of passive movements. This is consistent with a pre-movement (from here on referred to as an "efferent") account of action awareness because premotor and efference copy signals are only present in active movements, whereas the main source of movement information in passive movements is sensory feedback which is subject to time delays of conduction (and hence predicts later judgment times for passive movements). However, judgments of active toe movement onset time were less anticipatory than judgments of active finger movement onset time. This pattern of results is not consistent with a pure efferent account of conscious awareness of action onset - as this account predicts more anticipatory judgments for toe movements compared to finger movements. Instead, the data support the idea that conscious judgments of movement onset are based on efferent (i.e., premotor, efference copy) and reafferent (i.e., feedback from the movement) components.

Functional reorganization of the human brain after an arm amputation has been documented in several investigations, but as far as we know, there has been no report on amputees with skilled foot movement ability. To further assess the power of functional reorganization of the brain after an amputation, we investigated two bilateral upper-extremities amputees who were professional sculptors and painters with their feet. Performance tests showed that they possessed high foot movement ability. Functional MRI data indicated that toe tapping of the amputees not only activated the classical foot primary motor cortex, but also activated the hand area. In the T1-weighted MRI, the central sulci of both amputees kept their characteristic shape. Our study suggests that there is a remarkable power of neural plasticity in the motor cortex, and the maturation of the cortex develops in response to daily practice. The possible mechanisms of the reorganization are tentatively discussed.

The authors sought to gain further knowledge about activation of target muscles during imagery engagement in a motor task. Six hemiparetic patients and 9 healthy participants performed 3 real rises on tiptoes and then, after pausing, 3 imagery rises on tiptoes. Metronome beats guided the rate of rises and descents. Electromyographic (EMG) activity from the medial gastrocnemius and the rectus femoris muscles were monitored bilaterally throughout the performance of both tasks. In 3 healthy participants and 3 individuals with hemiparesis, EMG activity was related to the imagery task in at least 1 of the target muscles. Conversely, in the other participants, motor imagery practice was not accompanied by task-related EMG activity in the monitored muscles. In all cases, the increment in activation level during motor imagery practice was very low in comparison with that of real performance. The findings were not unequivocal; therefore, EMG activity may sometimes, but not always, be recorded during motor imagery practice both in healthy individuals and in poststroke hemiparetic participants. Further research is needed to align motor imagery practice with the objectives of motor rehabilitation.

The purpose of this study was to investigate and compare the movement-related brain potentials recorded from two groups of right-handed male study participants. One of the groups prepared for and conducted repetitive toe movements while the other prepared to carry out the same type of movement but finally did not execute it. The readiness potential, premotion positivity, motor potential and reafferent potential were recorded from 20 electroencephalogram electrodes. The most salient result was the greater readiness potential amplitude discovered in participants who ended up carrying out the movement, which indicates that the level of preparation in a repetitive task is greater when a final response is required. No group differences were found for the other potentials.

For many years, death implied immobility. Nevertheless, there are anecdotal reports of spontaneous or reflex movements (SRMs) in patients with Brain death (BD). The presence of some movements can preclude the diagnosis of BD, and consequently, the possibility of organ donation for transplantation. McNair and Meador [(1992), Mov Dord7: 345-347] described the presence of undulating toe flexion movements (UTF) in BD patients. UTF consists in a sequential brief plantar flexion of the toes. Our aim was to determine the frequency, characteristics and predisposing factors of UTF movements in a prospective multicenter cohort study of patients with BD. Patients with confirmed diagnosis of BD were assessed to evaluate the presence of UTF using a standardized protocol. All patients had a routine laboratory evaluation, CT scan of the head, and EEG. Demographic, clinical, hemodynamic and blood gas concentration factors were analyzed. amongst 107 BD patients who fulfilled the AAN requirements, 47 patients (44%) had abnormal movements. UTF was observed in 25 (23%) being the most common movement (53%). Early evaluation (OR 4.3, CI95% 1.5-11.9) was a predictor of UTF in a multivariate regression model. The somato-sensory evoked potential (SSEPs) as well as brainstem auditory evoked potentials (BAEPs) did not elicit a cortical response in studied patients with UTF. This spinal reflex is probably integrated in the L5 and S1 segments of the spinal cord. Abnormal movements are common in BD, being present in more than 40% of individuals. UTF was the most common spinal reflex. In our sample, early evaluation was a predictor of UTF. Health care professionals, especially those involved in organ procurement for transplantation, must be aware of this sign. The presence of this motor phenomenon does not preclude the diagnosis of BD.

The purpose of the present investigation was to explore whether and how the amplitude and/or duration parameters of anticipatory postural adjustments (APAs) affect the upward propulsive force (Delta FZamp) during rising on tiptoes from upright standing position. Seven subjects initiated the movement of rising on tiptoe from a strictly regulated initial body position at various velocities at the subjects' own spontaneous pace. In this experiment, electromyographic (EMG) activities of the muscles in the tibialis anterior (TA) and soleus, the goniogram in the ankle joint, and the anteroposterior and vertical ground reaction forces were simultaneously recorded. The average amplitude and the duration of the EMG activities and ground reaction force were measured, and the displacement of the center of body mass and the center of foot pressure (CP) were calculated and reported as the mean value plus its standard deviation. Delta FZamp correlated positively and significantly with the maximum backward CP shift, the average amplitude of the backward loading and the average EMG amplitude in the TA in the anticipation phase, whereas Delta FZamp did not correlate positively or significantly with the anticipatory duration of the backward CP shift of the backward loading and of the EMG activity in the TA. These results suggest that the amplitude parameters of the APAs associated with rising on tiptoes are dependent on the upward propulsive force, and that APAs may be directly involved not only with compensation of postural disturbance but also with increasing performance of the focal movement.

We investigate whether imagery of voluntary movements of different body parts activates somatotopical sections of the human motor cortices. We used functional magnetic resonance imaging to detect the cortical activity when 7 healthy subjects imagine performing repetitive (0.5-Hz) flexion/extension movements of the right fingers or right toes, or horizontal movements of the tongue. We also collected functional images when the subjects actually executed these movements and used these data to define somatotopical representations in the motor areas. In this study, we relate the functional activation maps to cytoarchitectural population maps of areas 4a, 4p, and 6 in the same standard anatomical space. The important novel findings are 1). that imagery of hand movements specifically activates the hand sections of the contralateral primary motor cortex (area 4a) and the contralateral dorsal premotor cortex (area 6) and a hand representation located in the caudal cingulate motor area and the most ventral part of the supplementary motor area; 2). that when imagining making foot movements, the foot zones of the posterior part of the contralateral supplementary motor area (area 6) and the contralateral primary motor cortex (area 4a) are active; and 3). that imagery of tongue movements activates the tongue region of the primary motor cortex and the premotor cortex bilaterally (areas 4a, 4p, and 6). These results demonstrate that imagery of action engages the somatotopically organized sections of the primary motor cortex in a systematic manner as well as activating some body-part-specific representations in the nonprimary motor areas. Thus the content of the mental motor image, in this case the body part, is reflected in the pattern of motor cortical activation.

The present study aimed at determining the three-dimensional organization of striatal activation during foot, hand, face and eye movements. Seven right-handed, healthy volunteers were studied at 1.5 T using blood oxygen level dependent (BOLD) contrast. The tasks consisted of self-paced flexion/extension of the right and left fingers and right toes, contraction of the lips and saccadic eye movements. For foot, hand and face movements, striatal activation was mainly found in the putamen with a somatotopical organization, the foot area being dorsal, the face area more ventral and medial, the hand area in between. Overlap between somatotopic territories was present, more prominent for hand-face than for foot-face or foot-hand areas. In the putamen, the activated areas of the ipsi- and contralateral hand areas were not identical, suggesting a partial segregation of the ipsi- and contralateral striatal sensorimotor projections. For saccadic eye movements, bilateral activation was observed at the junction between the body and the head of the caudate nucleus and in the right putamen. These data present evidence for a somatotopic organization of the human striatum which corresponds with the topography of corticostriatal projections described in the non-human primates.

The human primary sensorimotor cortex was investigated for somatotopic organization during motor imagery (IM) which was compared to motor execution (EM). Block designed BOLD (blood oxygen level dependent)-functional magnetic resonance imaging at 1.5 Tesla was applied in 14 right handed volunteers during imagined and executed tongue, finger and toe movements. BOLD-clusters were assessed for anatomically correct sensorimotor localization. Euklidian coordinates, relative signal change and correlation to the applied reference function were determined. Statistical means were calculated. IM recruited somatotopically organized primary sensorimotor representations of the precentral gyrus that reflected the homunculus and overlapped in part with EM representations. Mean BOLD-signals ranged from 1.93 to 3.18% for EM, and from 0.73 to 1.47% for IM. The results support the hypothesis that the primary sensorimotor cortex is active during IM and that IM and EM share common functional circuits.

Classification of movement-related potentials recorded from the scalp to their corresponding limb is a crucial task in brain-computer interfaces based on such potentials. Many features can be extracted from raw electroencephalographic signals to be used for classification, but the utilization of irrelevant or superfluous features is detrimental to the performance of classification algorithms. It is, therefore, necessary to select a small number of relevant features for the classification task. This paper demonstrates the use of two feature selection methods to choose a small number (10-20) of relevant features from a bank containing upward of 1000 features. One method is based on information theory and the other on the use of genetic algorithms. We show that the former is poorly suited for the aforementioned classification task and discuss the probable reasons for this. However, using a genetic algorithm on data recorded from five subjects we demonstrate that it is possible to differentiate between the movements of two limbs with a classification accuracy of 87% using as little as 10 features without subject training. With the addition of a simple coding scheme, this method can be applied to multiple limb classification and a 63% classification accuracy rate can be reached when attempting to distinguish between three limbs.

We measured the gliding resistance of canine and human tendons of intrasynovial origin and tendons of extrasynovial origin with and without paratenon, and investigated the structure of paratenon using scanning electron microscopy. In the canine study, seven intrasynovial flexor digitorum profundus (FDP) tendons, seven extrasynovial fibularis (peroneus) longus (FL) tendons with paratenon, and seven FL tendons without paratenon were used. In the human study, seven intrasynovial FDP tendons and seven extrasynovial palmaris longus (PL) tendons cut in half (one half with paratenon, the other half without paratenon) were used. The gliding resistance of each tendon was measured at 1, 5, 10, 20, 50, and100 flexion/extension cycles. The canine and human FDP tendons maintained a gliding resistance significantly lower than that of the other tendons at all observation points (P < 0.05). In the canine, the gliding resistance of the FL tendon with paratenon was significantly lower than that of the FL tendon without paratenon up to 50 flexion/extension cycles (P < 0.05), but the two were not significantly different at 100 cycles. In the human, the gliding resistance of PL tendons with paratenon was significantly lower than that of the PL tendons without paratenon at all measuring points (P < 0.05). Preservation of paratenon thus appears to decrease the gliding resistance of extrasynovial tendons after repetitive motion in vitro., (Copyright 2002 Wiley-Liss, Inc.)

Somatotopic organization of the human medial wall of the cerebral hemispheres was studied using functional MRI conducted at high field strength (3 T) with fine spatial resolution ( approximately 2 mm). Healthy subjects performed paced, repetitive movements of the fingers and toes. Within the supplementary motor area (SMA), two regions were identified: finger movements activated a region rostral and superior to that for toe movements. Two activation foci were also identified in the cingulate motor area: toe movements activated a region rostral and ventral to that activated by finger movements. All foci were located between the anterior and posterior commissures. Our results confirm previous human and non-human primate studies regarding the rostral-caudal organization of the SMA and CMA. The dorsal-ventral organization of the CMA, however, appears to be divergent from results derived from cortical stimulation studies conducted in non-human primates.

Two functional brain-mapping techniques, functional magnetic resonance imaging (fMRI) and cortical stimulation by chronically implanted subdural electrodes, were used in combination for presurgical evaluation of three patients with intractable, partial motor seizures. Brain mapping was focused on characterizing motor-related areas in the medial frontal cortex, where all patients had organic lesions. Behavioral tasks for fMRI involved simple finger and foot movements in all patients and mental calculations in one of them. These tasks allowed us to discriminate several medial frontal motor areas: the presupplementary motor areas (pre-SMA), the somatotopically organized SMA proper, and the foot representation of the primary motor cortex. All patients subsequently underwent cortical stimulation through subdural electrodes placed onto the medial hemispheric wall. In each patient, the cortical stimulation map was mostly consistent with that patient's brain map by fMRI. By integrating different lines of information, the combined fMRI and cortical stimulation map will contribute not only to safe and effective surgery but also to further understanding of human functional neuroanatomy.

We describe a clinical sign for identification of the superficial peroneal nerve. Flexion of the fourth toe accentuates the subcutaneous course of the cutaneous branches of the superficial peroneal nerve. Thirty feet from 15 volunteers were examined for presence of this sign. Twenty-six of 30 feet had a positive sign that was confirmed by infiltrating the observed nerve with 1% lignocaine and correlating the consequent area of hypoaesthesia with the known distribution of the superficial peroneal nerve.

We investigated steady-state movement-related cortical potentials elicited by fast repetitive movements (1/sec) with 50-channel EEG. The experimental design comprised a comparison (a) between unilateral movements of the digits and the toes and (b) between metronome-paced and self-paced initiation of the movements. A distinct biphasic pattern of electrical activity following movement onset was observed, namely a frontal negative peak at a latency of 90 ms (post-MP100) anda frontal positive peak at a latency of 310ms (post-MP300). Pacing exerted its effects mainly on the amplitude and on the latency of the post-MP300. Source analysis revealed that both peaks could be modelled by a single source. The source locations were highly reproducible across the metronome-paced and self-paced conditions, and, they followed the expected somatotopic organisation.

Objectives: A method by which potentials related to voluntary movement can be recorded noninvasively from the human spinal cord is presented., Methods: A novel signal processing technique performed on signals recorded by surface electrodes placed over the spinal column was used to filter time-locked back muscle noise, so that the only remaining signals were the spinal movement-related potentials from the brain to the limbs and vice versa., Results: The signals obtained from 7 subjects using this technique are shown and temporally compared with movement-related cortical potentials (MRCP) and muscle electromyogram. It is demonstrated that the spinal signal starts approximately 600 ms before the actual movement, and that some features of this signal correspond to changes in cortical potentials., Conclusions: These findings imply that the spinal cord is not a simple command-carrying medium from the brain to the limbs, and implies that some computational activities take place at the spinal cord level.

To evaluate changes in the human cerebral cortex after lower limb amputation, we studied repetitive toe movements using functional magnetic resonance imaging. The subject did not experience any phantom pain but had a vivid sensation of the phantom limb's presence and was able to imagine the movement of her phantom toes and ankle. Actual movement of her normal limb activated the contralateral supplementary motor area (SMA), the primary motor cortex (M1), and the primary somatosensory cortex (S1). Movement of her phantom limb activated the contralateral SMA and the M1. Imaginary movement of her normal toes without actual movement activated the contralateral SMA. The slice level that was activated by the movement of the phantom limb was shifted 8 mm caudally, suggesting that cortical reorganization had occurred after the lower limb amputation.

1. To be detected, movements of the interphalangeal joint of the big toe must be greater than at other joints. This poor acuity may arise because the anatomy of the foot and ankle results in poor coupling between the toe and the muscles that operate it. To vary this coupling, the effect of ankle position on proprioceptive acuity at the toe was measured. 2. We measured proprioceptive acuity at the toe with the ankle in different positions and found that ankle plantarflexion did improve acuity. This implies that, with the ankle at mid-range or dorsiflexed, toe movement is inadequately transferred to muscle fascicles. 3. To determine actual changes in fascicle length of the toe extensor, movements of extensor hallucis longus near the toe and at the muscle-tendon junction were measured during surgical exposure in one subject. Ankle position greatly affected movement transfer from toe to muscle-tendon junction: no tendon movement was transferred with the ankle dorsiflexed, but all movement was transferred with the ankle plantarflexed. 4. When the relationship between joint rotation and muscle fascicle length measured in vivo was used to express the smallest detectable movements of the toe as proportional changes in muscle fascicle length, these detectable changes were similar to those at all other limb joints. This suggests that change in muscle fascicle length is of major interest to the nervous system.

The present study aimed at determining the distribution and somatotopical organization of striatal activation during performance of simple motor tasks. Ten right-handed healthy volunteers were studied by using a 3-T whole-body magnetic resonance unit and echo planar imaging. The tasks consisted of self-paced flexion/extension of the right fingers or toes. Motor activation was found mainly in the putamen posterior to the anterior commissure (10 of 10 subjects) and the globus pallidus (6 subjects), whereas the caudate nucleus was activated in only 3 subjects, and in a smaller area. Thus, performance of a simple motor task activated the sensorimotor territory of the basal ganglia. Within the putamen, there was a somatotopical organization of the foot and hand areas similar to that observed in nonhuman primates. These data suggest that functional magnetic resonance imaging can be used to study normal function of the basal ganglia and should therefore also allow investigation of patients with movement disorders.

We investigated age-related changes in the distribution of body weight on soles of feet in 878 healthy subjects ranging from 5 to 80 years of age. By modifying Morton's Staticometer, we constructed an instrument for measuring body-weight distribution over three areas of soles of the feet, the big toe (inner forefoot), the other four toes combined (outer forefoot) and the heels for both feet, thus a total of six areas. The weights in the six areas were recorded at the completion of nine selected actions and postures. We observed that for inhaling and exhaling standing postures, generally younger subjects had a ratio close to 1:2:3 for weights recorded for the inner toe:outer toes:heels as observed by Morton, but elderly subjects had a smaller value than 3 for the heel. The body-weight distribution tended to shift from heels to outer toes across age groups, which was more distinctly observed in women than in men.

The somatosensory evoked magnetic fields (SEFs) and evoked potentials (SEPs) following passive toe movement were studied in 10 normal subjects. Five main components were identified in SEFs recorded around the vertex around the foot area of the primary sensory cortex (SI). The first and second components, 1M and 2M, were identified at approximately 35 and 46 ms. Equivalent current dipoles (ECDs) of both 1M and 2M were estimated around SI in the hemisphere contralateral to the movement toe, and were probably generated in area 3a or area 2, which mainly receive inputs ascending through muscle and joint afferents. The large inter-individual difference of 1M and 2M in terms of ECD orientation was probably due to a large anatomical variance of the foot area of SI. The third and fourth components, 3M and 4M, were identified at approximately 62 ms and 87 ms, respectively. They appeared to be a single large long-duration component with two peaks. Since the 3M and 4M components were significantly larger than the 1M and 2M components in amplitude and their ECD location was significantly superior to that of 1M and 2M, we suspected that they were generated in different sites from those of 1M and 2M, probably area 3b or area 4. Four components, 1E, 2E, 3E and 4E, were identified in SEPs, which appeared to correspond to 1M, 2M, 3M and 4M, respectively. The variation observed in the scalp distribution of the primary component, 1E, could be accounted for by the variation of the orientation of ECD of the 1M component. There was a large difference in the waveform of the long-latency component (longer than 100 ms) between SEFs and SEPs. The 5E of SEPs was a large amplitude component, but the 5M of SEFs was small or absent. We speculate that this long-latency component was generated by multiple generators.

Objective: Determine the generator sources for actual and imagined (simulated) movements of fingers and toes., Design: Observational., Setting: Electroencephalography laboratory., Subjects: Ten asymptomatic adult volunteers., Main Outcome Measure: Comparison of cortical electrical fields and their dipole sources in actual and imagined movements., Results: Cortical electrical fields tend to be contralateral with actual movements and midline with imagined movements. Dipole sources of actual movements include a contralateral contribution from the frontal (primary motor) area. Sources of imagined movements are midline or ipsilateral., Conclusions: (1) The motor networks underlying the generation of actual and imagined movements are different. (2) Imagined movements lack a primary motor area source, but involve medial and ipsilateral structures. (3) The effectiveness of imagined movements in rehabilitation may stem from activation of premotor or supplementary motor areas.

Movements of right and left index fingers, right toe and tongue were studied by EEG measurement in the alpha and gamma (30-40 Hz) bands. The EEG was recorded with a 56-electrode array over pre- and postcentral areas. For each movement the average power decrease, as a measurement of the event-related desynchronization or power increase in narrow frequency bands, was calculated. Single-trial data from 8 electrodes, 3 frequency bands and 4 time points within a 1 sec window were subject to a classification task. It was found that, based on single EEG trials, the data from the 4 movements could be differentiated with an accuracy of 70% when alpha and gamma band activity were used but only with 58% in the case of the alpha band activity alone. This shows that the gamma band activity or 40 Hz EEG is strongly related to planning of a specific movement and therefore, improves the accuracy of classification significantly.

40-Hz oscillations were measured during finger, toe and tongue movement using an electrode array of 56 electrodes over the pre and post central areas. Each movement was made 150 times in intervals of 12 s. The average power increase in narrow frequency bands between 8 and 40 Hz was then calculated and the topographical distribution studied. 40-Hz oscillations were only found contralateral over the hand area for finger movements, close to the vertex for toe movements and bilateral symmetrical for tongue movements. The maxima of the 40-Hz oscillations occurred before movement onset.

In order to understand the function of toes during free walking, movements of the toes of 30 normal adults were measured with the electrogoniometers. The angular changes of the interphalangeal (IP) joint of the 1st toe and the distal interphalangeal (DIP) joints of the 2nd to 4th toes, the ground reaction force, foot switch signal and the pressure changes in the forefoot were recorded simultaneously. The relationships between these measurements were then investigated. During the foot-flat phase, the IP joint of the 1st toe stayed at a flexed position, while the DIP joints of the 2nd to 4th toes remained at a slightly extended or neutral position but there was scarcely any pressure on the toe tips (0-0.3 kg/cm3). After the heel-off, the pressure on the 1st toe tip gained with increasing flexion of the IP joint of the 1st toe. The mean of the maximum angles was 13 +/- 5 (mean +/- SD) degrees. After the heel-off, the DIP joints of the 2nd and 3rd toes remained in the extended position in 16 cases (6.6 +/- 3.1 and 6.3 +/- 3.4 degrees) and appeared to stay at a flexed position in 14 cases (10.0 +/- 7.8 and 8.0 +/- 5.3 degrees). The DIP joint of the 4th toe remained in the extended position in all cases (9.2 +/- 8.5 degrees). The pressure of the toe tips increased. The magnitude of the pressure of the extended toe tips was higher than that in the flexed toe tips. The pressure of the toe tips of the 1st to 4th toes reached the maximum much earlier than that of the toe-off. From these observations, we conclude that the function of the toes during free walking seems to stabilize the foot by extending a contact area with floor mainly after the heel-off.

Normal subjects have been tested for interhemispheric transfer (IT) of visuo-motor information using a simple reaction time (RT) paradigm and lateralized stimuli and responses (the so-called Poffenberger paradigm). In this paradigm IT time is assumed to correspond to the RT difference between crossed and uncrossed stimulus-response combinations (CUD). In Experiment 1, two types of movements were used: a unilateral flexion of the thumb and a unilateral plantar flexion of the big toe. A reliable CUD (7.4 msec) was found only with manual responses. Changing stimulus retinal eccentricity (10 degrees vs. 70 degrees) or attentional demands (blocked vs. random stimulus presentation) did not result in any reliable effect on the CUD. In Experiment 2 the number of RTs for each subject was considerably increased and several visual field sites (from areas close to the vertical meridian to the monocular crescent) were tested. Notwithstanding these modifications, this experiment confirmed the lack of CUD found for foot responses in Exp. 1. Taken together, these results are in keeping with a less lateralized hemispheric control of distal foot movements in comparison to hand movements.

The effect of local heat treatment of the sciatic nerve was assessed using the toe-spreading test, which mainly assesses the motor function of the sciatic nerve. A 5 mm long segment of the nerve was heated at temperatures from 42.0 to 45.0 degrees C in vivo using a brass thermode. Hyperthermia led to a decrease in spreading of the toes. Recovery from functional loss took place in all cases, and this recovery was completed in 4 weeks. A 50 per cent functional loss in 50 per cent of the treated animals was observed after 58, 32 and 12 min of heating at 43.0, 44.0 and 45.0 degrees C respectively.

Voluntary movements are preceded by a slow electrical potential of the brain (Bereitschafts-potential, BP) or readiness potential. The BP is accompanied by a magnetic field shift of similar time characteristics (Bereitschaftsmagnetfeld, BM). The BM preceding volitional right foot or toe movements was recorded from anterior, posterior, and lateral positions of the scalp using a SQUID (Superconducting Quantum Interference Device) third-order gradiometer. Controls were implemented to reduce head movements, which were simultaneously recorded with a mechanograph. The results showed that movements of the lower extremities are also preceded by a BM. However, contrary to finger movements, BMs with field lines directed into the head were found predominantly for foot movements and exclusively for toe movements. The BM preceding foot movements was maximum over a position 2 cm left of the vertex, i.e., contralateral to the movement. Two centimeters right of the vertex it was smaller, thus exhibiting a normal contralateral preponderance and not sharing the paradoxical side preponderance of the electrical BP preceding foot or toe movements. The BM preceding toe movements was only apparent at the vertex and was smaller than the one preceding foot movement. This may suggest a source that is located still deeper in the brain than with foot movements.

The cerebral potentials associated with voluntary, self-paced rapid flexions of (1) right fingers, (2) left fingers, (3) right toes, and (4) left toes were compared in the same experiment using 32 right- and left-handed subjects. The Bereitschaftspotential (BP) or readiness potential was, in the first half of the foreperiod, bilaterally symmetrical for both finger and toe movements of either side. In the later foreperiod there were differences: Finger movements showed two maxima, an early one at Cz and a late one, which was lateralized toward the contralateral precentral region. With toe movements, the maximum BP amplitude was always at Cz and not lateralized and was twice as large as with finger movements. The data are compatible with the view that two principal sources of different spatial and temporal characteristics are active in the foreperiod of a voluntary movement. The early generator is probably the supplementary motor area (SMA) on the mesial surface of the hemispheres; the later is the primary motor cortex (MI) which is lateralized for finger but not for toe movements. In lateral leads, rather remote from the mesial source, the BP for toe movements showed a small but significant ipsilateral preponderance, which is obviously due to the fact that dipole sources located on the mesial surface of the hemispheres point to the opposite direction as compared to those on the convexity.(ABSTRACT TRUNCATED AT 250 WORDS)

In this study, the brain potentials related to voluntary, self-paced plantarflexions of the left toes, flexion of the right knee and isometric extensions of the left hip were examined in 3 groups of 10 subjects each. In the first half of the foreperiod, the Bereitschaftspotential (BP) or readiness potential for all movements was symmetrically distributed over both hemispheres. For toe and knee movements, an ipsilateral preponderance of the BP developed in the later foreperiod, which was statistically significant for toe movements. For hip movements, BP topography was symmetrical during the entire foreperiod including its second half. Since finger, hand or shoulder movements of previous experiments show a strong contralateral preponderance of the BP, the results are discussed as further support of the hypothesis that the lateralisation of the BP is due to the orientation of the precentral electrical field vector generated by an active source in the MI motor cortex. Thus, part of the somatotopic representation of the human precentral gyrus can be mapped by this non-invasive means: upper limb movements are located on the convexity; toe, foot and knee movements are generated on the mesial cortex between the hemispheres; and hip movements seem to be located at the mantle edge.

The cerebral potentials associated with self-paced rapid dorsiflexion and plantarflexion of the left toes were compared in the same experiment using 10 subjects 5 of whom were female and 5 of whom were male. The EEG was recorded from C3, C1, Cz, C2 and C4 including computed bipolar recordings C4/C3 and C2/C1. For both kinds of movements, the Bereitschaftspotential (BP) or readiness potential was bilaterally symmetrical in the first half of the foreperiod. In the later foreperiod, an ipsilateral preponderance of negativity (IPN) developed. The direction of toe movement had no effect on the IPN. The etiology of the paradoxical BP side preponderance prior to toe movements is discussed which can probably be referred to the unique dipole orientation of a generator situated on the mesial cortical surface in the depth of the interhemispherical fissure.