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PubMed2001

Chronic motor cortex stimulation for phantom limb pain: a functional magnetic resonance imaging study: technical case report.

OBJECTIVE AND IMPORTANCE: Chronic motor cortex stimulation has provided satisfactory control of pain in patients with central or neuropathic trigeminal pain. We used this technique in a patient who experienced phantom limb pain. Functional magnetic resonance imaging (fMRI) was used to guide electrode placement and to assist in understanding the control mechanisms involved in phantom limb pain. CLINICAL PRESENTATION: A 45-year-old man whose right arm had been amputated 2 years previously experienced phantom limb pain and phantom limb phenomena, described as the apparent possibility of moving the amputated hand voluntarily. He was treated with chronic motor cortex stimulation. INTERVENTION: Data from fMRI were used pre- and postoperatively to detect shoulder and stump cortical activated areas and the "virtual" amputated hand cortical area. These sites of preoperative fMRI activation were integrated in an infrared-based frameless stereotactic device for surgical planning. Phantom limb virtual finger movement caused contralateral primary motor cortex activation. Satisfactory pain control was obtained; a 70% reduction in the phantom limb pain was achieved on a visual analog scale. Postoperatively and under chronic stimulation, inhibiting effects on the primary sensorimotor cortex as well as on the contralateral primary motor and sensitive cortices were detected by fMRI studies. CONCLUSION: Chronic motor cortex stimulation can be used to relieve phantom limb pain and phantom limb phenomena. Integrated by an infrared-based frameless stereotactic device, fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication. Pain control mechanisms and cortical reorganization phenomena can be studied by the use of fMRI.

Electric Stimulation Therapy↗
PubMed1996

Human cerebral activity with increasing inspiratory force: a study using positron emission tomography.

Human cerebral activity with increasing inspiratory force: a study using positron emission tomography. J. Appl. Physiol. 81(3): 1295-1305, 1996.--The major aim of this study was to use positron emission tomography (PET) to assess dose-dependent effects of inspiratory loads on relative regional cerebral blood flow as an indication of neuronal activation and recruitment. Six normal men underwent H2 15O-PET scanning during unloaded breathing and with external inspiratory loads (generating mouth pressures of -5, -10, and -15 cmH2O); positive-pressure ventilation against relaxed respiratory muscles acted as control. During unloaded breathing, the supplementary motor area was significantly activated. With the addition of the smallest load, activations also occurred in the right premotor area and bilaterally in the superolateral motor cortex (MI) in areas previously shown to be activated with deeper breathing. There was little further change in these areas with greater loads. Additional force-related activations occurred in the inferolateral sensorimotor cortex, parietal cortex, and midbrain/hypothalamus. The results suggest that volitionally induced increases in inspiratory muscle force are achieved via a complex integration of neuronal activations in cortical and subcortical regions associated with motor control.

Adult↗
PubMed1991

The early commitment of fetal neurons to the limbic cortex.

The limbic-system-associated membrane protein (LAMP) is expressed early in cerebral cortical development by migrating and postmigratory neurons in limbic regions such as the prefrontal and perirhinal cortices (Horton and Levitt, 1988), but not by nonlimbic neurons such as in the primary sensory and motor cortices. In the present study, we used LAMP expression to evaluate the timing and potential cell-lineage and environmental determinants of the commitment of cerebral cortical neurons to limbic and nonlimbic phenotypes. The cerebral wall, containing either presumptive perirhinal or sensorimotor cortex, was removed prior to [embryonic day (E) 12, 14] or just after (E17) the onset of LAMP expression, labeled with fast blue, and placed into cavities in either perirhinal or sensorimotor regions of postnatal day (P) 1 hosts. Host animals were allowed to survive until at least P10, and surviving transplanted cells were counted and evaluated for LAMP expression. Sensorimotor cortical neurons transplanted at E14 or E17, in either homotopic or heterotopic locations, did not express LAMP. In contrast, a high percentage of perirhinal cortical neurons transplanted at either E14 or E17, whether situated in sensorimotor or perirhinal regions of the host, expressed the limbic marker protein. Surprisingly, neurons from E12 donors exhibited patterns of LAMP expression that reflected their new location in the host rather than their embryonic origin. The data suggest that there is an early pliant period in which precursor and early differentiating cells remain uncommitted to a particular cortical regional phenotype. After this period, one aspect of the molecular phenotype (determined by LAMP expression) of neurons destined for sensorimotor and allo- and mesocortical regions has become immutable by environmental factors in the host.

Animals↗
PubMedDate not supplied

Activity of adenylate cyclase and 5'-nucleotidase in the sensorimotor and limbic structures of the brain in rats after manipulatory training.

Adenylate cyclase (AC) and 5'-nucleotidase (NT) activities were measured in the limbic (amygdala, hippocampus) and sensorimotor (cortex, striatum) structures of the brain in three groups of rats: untrained rats and rats which were good and poor learners in training to perform movements involving pushing against an obstruction. After training, AC activity decreased in all structures studied. Activity decreased in the cortex and striatum to a greater extent in good learners, and in the amygdala in poor learners. NT activity decreased in all brain structures apart from the striatum, to a greater extent in rats which were less able to learn to produce movements involving prolonged pushing. The striatum was the only structure in which increases in NT activity occurred, from the lowest initial level in the control group. 1.0 +/- 0.04 microgram P(i)/mg protein/min, to 1.3 +/- 0.1 micrograms P(i)/mg protein/min in poor learners and to 2.0 +/- 0.1 micrograms P(i)/mg protein/min in good learners. Interhemisphere asymmetries in AC activity in the cortex and hippocampus were seen, along with an interhemisphere difference in NT activity in the amygdala. Thus, the activity of enzymes involved in adenine and cAMP biosynthesis changed in different ways in the limbic and sensorimotor structures of the brain, depending on the ability of rats to learn. The increase in NT activity after training of rats, which was limited to the striatum, may reflect a special role for the purinergic system in these structures in mediating sensation-regulated movements.

5'-Nucleotidase↗
PubMed2001

Functional imaging of the brain in sedated newborn infants using near infrared topography during passive knee movement.

Near infrared topography was used for functional imaging of the sensorimotor cortex of newborn infants during passive knee movement under sedated sleep. Contralateral knee movement caused a marked increase in oxyhemoglobin and total hemoglobin from the baseline values at almost all locations in the primary sensorimotor area of all neonates and a decrease in local deoxyhemoglobin in six of seven neonates. During ipsilateral knee movement, oxyhemoglobin and total hemoglobin showed slighter changes at a few locations, equal to 30% (mean) and 29% (mean) of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes were 11.9 s for oxyhemoglobin and 19.1 s for deoxyhemoglobin, demonstrating that oxyhemoglobin has a much faster response than does deoxyhemoglobin.

Brain Mapping↗
PubMed1996

Comparison of human cerebral activation pattern during cutaneous warmth, heat pain, and deep cold pain.

1. We wished to determine whether there are differences in the spatial pattern and intensity of synaptic activity within the conscious human forebrain when different forms and intensities of innocuous and noxious thermal stimuli are experienced. Accordingly, positron emission tomography (PET) with intravenous injection of H2(15)O was used to detect increases in regional cerebral blood flow (rCBF) in normal humans as they discriminated differences in the intensity of noxious and innocuous thermal stimulation applied to the nondominant (left) arm. After stereotactic registration, subtraction images were formed from each subject by subtracting counts of emissions obtained during lower-intensity stimulation from those obtained during stimulation at higher intensities. A statistical summation analysis (Z score) of individual voxels was performed. In addition, volumes of interest were chosen on the basis of a priori hypotheses and the results of previously published PET studies. In both types of analysis, statistical thresholds were established with corrections for multiple comparisons. 2. Twenty-seven subjects were divided into three groups of nine subjects each for the three phases of this investigation. For studies in which repetitive contact heat stimuli were used, each subject was instructed in magnitude estimation on the basis of a scale for which 0 indicated "no heat sensation," 7 "just barely painful," and 10 "just barely tolerable." For the study of pain elicited by immersion of the hand in cold water, subjects were instructed to use a scale in which 0 represented "no pain" and 10 represented just barely tolerable pain. 3. In the warm-discrimination study, two intensities of innocuous heat (36 and 43 degrees C) were applied with a thermode as repetitive 5-s contacts to the volar forearm for a total of approximately 100 s, 8 stimuli before and 12 during each scan. Each temperature was applied on alternate scans for a total of four scans per subject. Neither stimulus was rated painful. All subjects discriminated the 43 degrees C stimulus (average rating 5.90 +/- 1.43, mean +/- SD) from the 36 degrees C stimulus (1.96 +/- 1.08, mean +/- SD; t = 13.19, P < 0.0001). Significant increases in rCBF to the 43 degrees C stimuli were found in the contralateral ventral posterior thalamus, lenticular nucleus, medial prefrontal cortex (Brodmann's areas 10 and 32), and cerebellar vermis. 4. The procedure for discriminating between noxious and innocuous heat stimuli was identical to that used for warm discrimination except that the stimulation temperatures were 40 and 50 degrees C. All subjects rated the 50 degrees C stimuli as painful (average rating 8.9 +/- 0.9, mean +/- SD) and the 40 degrees C stimuli as warm, but not painful (2.1 +/- 1.0). Significant rCBF increases to 50 degrees C stimuli were found contralaterally in the thalamus, anterior cingulate cortex, premotor cortex, and secondary somatosensory (S2) and posterior insular cortices. Significant activity also appeared within the region of the contralateral anterior insula and lenticular nucleus. The ipsilateral premotor cortex and thalamus, and the medial dorsal midbrain and cerebellar vermis, also showed significant rCBF increases. Cerebral blood flow (CBF) increases just below the threshold for statistical significance were seen in the contralateral sensorimotor cortex [primary motor cortex (M1)/primary somatosensory cortex (S1)]. 5. For discrimination between tonic innocuous cold and tonic cold pain, the left hand was immersed to the wrist, throughout each of six scans, in water kept at an average temperature of either 20.5 +/- 1.15 degrees C (mean +/- SD) or 6.02 +/- 1.18 degrees C (mean +/- SD) on alternate scans. All subjects rated the intensity of the stimuli on a scale in which 0 indicated no pain and 10 represented barely tolerable pain. Subjects rated the 20 degrees C water immersion as painless (average rating 0.18 +/- 0.48, mean +/- SD), but gave ratings indicating i

Adolescent↗
PubMed1997

Supratentorial glioma manifesting as acute onset of pure motor hemiparesis--case report.

A 68-year-old male presented with an anaplastic astrocytoma deep in the sensorimotor cortex manifesting as acute pure motor hemiparesis suggestive of a vascular mechanism rather than tumor mass effect. Perfusion-weighted magnetic resonance (MR) imaging showed a significant decrease of blood flow in the sensorimotor area, where fluid-attenuated inversion recovery imaging demonstrated a prominently edematous area. Angiography also suggested ischemia with poor visualization of the precentral and central arteries. Diffusion-weighted MR imaging failed to identify the edema as cytotoxic or vasogenic due to technical problems. Brain tumors may manifest through impairment of peritumoral blood supply, which can be clarified by recent MR methods.

Aged↗
PubMed1995

[Adenylate cyclase and 5'-nucleotidase activities in the sensorimotor and limbic structures of the rat brain after training in a manipulative skill].

The activities of adenylate cyclase (AC) and 5'-nucleotidase (NT) were studied in the limbic (amygdala, hippocampus) and sensorimotor (cortex, striatum) brain structures of three rat groups: control (without training), not well and well learning to perform movements with pushing the operandum. It was found, that after training the activity of AC was decreased in all structures studied. Moreover, in the cortex and the striatum the decrease was more pronounced in the group of well learning rats, while in the amygdala--in not well learning ones. The activity of NT in all brain structures, excepting the striatum, was more significantly decreased in the rats with low ability to learn the movements with prolonged pushing. Only in the striatum the increase of NT activity (initially the lowest in the control animals--1.0 +/- 0.04 microgram P(i)/mg protein/min) up to 1.3 +/- 0.1 in not well and up to 2.0 +/- 0.1 in well learning animals was found. The interhemispheric [correction of intrahemispheric] asymmetry of AC activity in the cortex and of NT in the hippocampus was revealed. Thus, the changes of the activity of the enzymes, participating in the biogenesis of adenosine (NT) and c-AMP (AC) are different in the limbic and sensorimotor structures dependently on learning ability of rats. The increase of NT activity after learning only in the striatum could reflect a specific role of purinergic system of this brain structure in the regulation of sensory controlled movements.

5'-Nucleotidase↗
PubMed1985

[Enzyme activity and content of glycerophosphate shuttle metabolites in the cortex and medulla oblongata during hyperbaric oxygenation therapy of acute hemorrhage].

The experiments on cats have demonstrated that hyperbaric oxygenation (303.9 kPa, 60 min) in acute blood loss (24.0 +/- 0.8 ml/kg) has an essential effect on glycerophosphate shuttle mechanism: it stimulates mitochondrial glycerol-3-phosphate dehydrogenase in the sensorimotor cortex and medulla oblongata, providing glycerol-3-phosphate dehydrogenation, activates cytoplasm hydrogen delivery to mitochondrial respiratory chain, prevents glycerol-3-phosphate and NADH level increase and cytoplasm glycerol-3-phosphate dehydrogenase inhibition, limiting lactate production.

Animals↗
PubMed1992

Patterns of projections from area 2 of the sensory cortex to area 3a and to the motor cortex in cats.

Peripheral information reaches the motor cortex partly through corticocortical pathways that arise from two functional subdivisions, area 2 and area 3a, of the sensory cortex. These sensory areas are synaptically linked with one another. The patterns of connectivity and the different submodality input that each area receives suggest that they send different efferent signals to the motor cortex. The projections from area 2 to area 3a and to the motor cortex were studied with retrogradely transported fluorescent tracers. The pattern and distribution of neuronal labeling in area 2 was determined following injections of different tracers into the forelimb regions of area 3a and the motor cortex. The results showed that the projections from area 2 to the two target regions were topographically and somatotopically related. Multiple clusters of motor cortex projection neurons were found in area 2, and these clusters overlapped extensively with clusters of area 3a projection neurons. Although cells labeled with one of the dyes were often in close proximity to cells labeled with the other dye, no double-labeled cells were found. Two different laminar patterns were seen for the two populations of neurons. The projection to area 3a originated from cells located in layers II-III and layers V-VI. The projection to the motor cortex originated from cells spread throughout layers II-IV, but predominantly in layer III. Differences in laminar arrangement of the two populations of cells suggest a directional flow of information processing in the sensorimotor cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Limbic seizures originating in the olfactory bulb: an electro-behavioral and glucose metabolism study.

We studied seizures which were induced by a microinjection of kainic acid (KA) into the unilateral olfactory bulb (OB) in the rats. The first epileptiform discharge appeared in the OB, was then propagated to the amygdala and the hippocampus unilaterally, and finally propagated to the unilateral sensori-motor cortex. Consistent graded behavioral changes, almost identical to those of the amygdaloid and hippocampal seizures, occurred during the development of the seizures, and three stages were classified: stage 1 was staring, stage 2 consisted of masticatory movement and stage 3 demonstrated rearing and rearing and falling. Local cerebral glucose utilization (LCGU) measured with the [14C]2-deoxyglucose method revealed a graded propagation of seizure activities at each stage in the unilateral structures. At stage 1, the increased activities propagated from the OB localized in the anterior olfactory nucleus; at stage 2, the endopiriform nucleus, the nucleus accumbens, the entorhinal cortex, the ventral globus pallidus and the globus pallidus were all activated; at stage 3, the thalamic nuclei (mediodorsal, ventrolateral, ventromedial and centromedian nuclei), the substantia nigra pars reticulata, the entopeduncular nucleus and the sensorimotor cortex were also activated. The globus pallidus, which receives afferent fibers from the nucleus accumbens, was the first structure that was activated metabolically among the extralimbic structures. No metabolic activation occurred in the amygdala and the hippocampus in spite of the early propagation of epileptiform discharges to these structures on EEG. These results suggest that OB seizures involve the limbic structures, while the amygdala and the hippocampus have a little contribution to OB seizures. In addition, the nucleus accumbens plays an important role as a functional interface between the limbic and the motor system in OB seizures.

Animals↗
PubMed2004

Feedforward and feedback processes in motor control.

In this study, we utilized functional magnetic resonance imaging (fMRI) to examine which brain regions contribute to feedback and feedforward motor control processes. Several studies have investigated the contributions of cortical and subcortical brain regions to motor performance by independently varying factors such as movement rate, force, and speed, and observing the neural responses. Such studies have contributed greatly to our understanding of neural coding of movement variables. Under natural movement conditions, however, these factors interact in a complex manner to produce differing performance levels. In the current investigation, we induced performance changes in a less constrained way, by having subjects move a joystick to hit targets of differing sizes on an LCD screen. These parametric changes in target size resulted in the well-known speed-accuracy tradeoff effect, allowing us to examine the brain regions responsive to global shifts in motor performance levels. That is, movements made to larger targets relied more on feedforward control whereas movements made to smaller targets relied more on feedback control. Using functional MRI, we identified two sets of brain regions in which activation was modulated with task difficulty. Areas exhibiting activation that was positively correlated with increasing target size included primary motor cortex, premotor cortex, and the basal ganglia, regions that are typically classified as playing a role in force control and movement planning. Brain regions whose activation was negatively correlated with increasing target size included the ipsilateral sensorimotor cortex, multiple cerebellar regions, and the thalamus. These areas contributed to motor performance under higher levels of task difficulty. The results elucidate cortical and subcortical brain regions that are responsive to global shifts in motor performance, reflecting changes along the continuum of feedforward and feedback motor control.

Adult↗
PubMed1988

Vascular response to carbon dioxide in areas with and without diaschisis in patients with small, deep hemispheric infarction.

The reactivity of cerebral blood vessels to changes in PaCO2 in areas of the cerebral cortex with or without diaschisis was investigated in 13 patients in a subacute or chronic stage after a small capsular infarct. A focal area of hypoperfusion (area of diaschisis) was detected in the ipsilateral sensorimotor cortex in each patient. Hyperventilation caused a significant reduction of regional cerebral blood flow in the area without diaschisis and only a tendency for regional cerebral blood flow to decrease in the area with diaschisis; CO2 inhalation induced a slight increase in regional cerebral blood flow in the area without diaschisis and a significant increase in regional cerebral blood flow in the area with diaschisis. Regional cerebral blood flow reactivity to hypocapnia was significantly less in the area with diaschisis than in the area without, whereas the hypercapnic response was more marked in the area with diaschisis than in the area without. Our results suggest that in the area with diaschisis, the arterioles may be abnormally vasoconstricted at rest such that they cannot constrict further in response to hypocapnia but can dilate more during hypercapnia than in the area without diaschisis. This excessive resting vasoconstriction may result from decreased tissue elaboration of CO2 due to local decrease of metabolic function.

Adult↗
PubMed2001

Predictability modulates human brain response to reward.

Certain classes of stimuli, such as food and drugs, are highly effective in activating reward regions. We show in humans that activity in these regions can be modulated by the predictability of the sequenced delivery of two mildly pleasurable stimuli, orally delivered fruit juice and water. Using functional magnetic resonance imaging, the activity for rewarding stimuli in both the nucleus accumbens and medial orbitofrontal cortex was greatest when the stimuli were unpredictable. Moreover, the subjects' stated preference for either juice or water was not directly correlated with activity in reward regions but instead was correlated with activity in sensorimotor cortex. For pleasurable stimuli, these findings suggest that predictability modulates the response of human reward regions, and subjective preference can be dissociated from this response.

Adolescent↗
PubMed1999

Clinical applications of functional MRI at 1.0 T: motor and language studies in healthy subjects and patients.

In this article we describe clinical applications of functional MRI (fMRI) at 1.0 T. All experiments were performed on a commercially available 1.0-T system (Magnetom Impact Expert, Siemens AG, Erlangen, Germany) using a blood oxygen level-dependent (BOLD)-sensitive multi-slice EPI technique (TE 66 ms, 4 mm slice thickness, 210 mm field of view, 64 x 64 acquisition matrix). Different paradigms for localization of the motor cortex and for language lateralization were tested in healthy subjects and patients. Methodological considerations concerning the development of the paradigms are also described. In all healthy subjects, motor activation elicited BOLD signal changes in the sensorimotor cortex, permitting identification of primary motor and sensory cortical areas. Furthermore, focal activation of different cortical areas by a language task was possible in 6 of 10 subjects. Nineteen motor studies were performed in 18 patients with supratentorial lesions, in most cases prior to neurosurgical procedures. In 14 studies, fMRI results demonstrated the localization of the motor hand areas relative to the lesion. The results proved valuable for preoperative planning and contributed to therapeutical decisions. We conclude that functional MRI for clinically relevant applications, such as localization of motor and language function, is feasible even at a field strength of 1.0 T without dedicated equipment.

Adult↗
PubMed2006

Motor imagery and EEG-based control of spelling devices and neuroprostheses.

A brain-computer interface (BCI) transforms signals originating from the human brain into commands that can control devices or applications. With this, a BCI provides a new non-muscular communication channel, which can be used to assist patients who have highly compromised motor functions. The Graz-BCI uses motor imagery and associated oscillatory EEG signals from the sensorimotor cortex for device control. As a result of research in the past 15 years, the classification of ERD/ERS patterns in single EEG trials during motor execution and motor imagery forms the basis of this sensorimotor-rhythm controlled BCI. The major frequency bands of cortical oscillations considered here are the 8-13 and 15-30 Hz bands. This chapter describes the basic methods used in Graz-BCI research and outlines possible clinical applications.

Communication Devices for People with Disabilities↗
PubMed2004

Bimanual coordination: neuromagnetic and behavioral data.

It has been suggested that bimanual coordination is associated with stronger activation of the left motor cortex in right-handers. The aim of the present study was to investigate whether left motor cortex dominance constitutes a fundamental feature of bimanual coordination. We investigated neuromagnetic responses while subjects performed a bimanual tapping task using a 122-channel whole-head neuromagnetometer. Three neuromagnetic sources localized in the primary sensorimotor cortex of each hemisphere were found. Sources represent neuromagnetic correlates of the motor command and of somatosensory feedback. Since we found no differences of amplitudes or latencies of corresponding sources of both hemispheres, our data suggest that dominance of the left motor cortex is not a fundamental characteristic for bimanual coordination.

Adult↗
PubMed1997

Transplantation of fetal neocortex ameliorates sensorimotor and locomotor deficits following neonatal ischemic-hypoxic brain injury in rats.

Ischemic brain injury in neonates can result in the degeneration of cortical and subcortical areas of brain and is associated with neurologic deficits. One approach to restoring function in conditions of ischemic brain injury is the use of neural transplants to repair damaged connections. This approach has been shown to reestablish neural circuitry and to ameliorate associated motor deficits in models of neonatal sensorimotor cortex damage. In this study, we utilized the Rice et al. rodent model of neonatal ischemic-hypoxic (IH) brain injury to assess whether transplantation of fetal neocortical tissue can promote functional recovery in tests of sensorimotor and locomotor ability throughout development and as adults. We show that animals that received neocortical grafts 3 days following the IH injury performed significantly better as adults on two measures of motor ability, the Rota-Rod treadmill and apomorphine-induced rotations, than did control animals that received sham transplants after the IH injury. Transplants were identifiable in 72% of the animals 10-12 weeks after implantation. Histochemical studies revealed that while the transplanted tissue did not establish normal cortical cytoarchitecture, cells and fibers within the grafts stained for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), choline acetyl transferase (ChAT), cholecystokinin (CCK), and glial fibrillary acidic protein (GFAP). These results suggest that transplantation of fetal neocortical tissue following IH injury in the neonatal period is associated with amelioration of motor deficits and that the grafted tissue demonstrated a neurochemical phenotype that resembled normal neocortex. This approach warrants continued investigation in light of potential therapeutic uses.

Animals↗