Localization of sensorimotor cortex: the influence of Sherrington and Cushing on the modern concept

According to Penfield, the work of Charles Sherrington's laboratory forced a change from the long-held concept of a broad, overlapping sensorimotor cortex to the concept of a narrow, discrete pre-Rolandic motor cortex separate from the post-Rolandic sensory strip. Harvey Cushing, one of the founders of modern neurosurgery, coined the term narrow motor strip. Cushing also appears to have been the first to color the precentral gyrus in a mosaic pattern and to use red coloring for the motor cortex and blue for the sensory cortex. Cushing's red and blue color coding is still used in textbooks, nearly 100 years later. In this article, we review the historical evolution of and the evidence for the concept of narrow and discrete motor and sensory strips anterior and posterior to the Rolandic cortex. A review of the historical development of the concept and recent physiological studies reaffirms the proposition that the motor and sensory areas are much broader and more complex than they were thought to be in the classic teaching that originated with Sherrington and Cushing.

Simple partial seizures: clinicofunctional correlation--a case report

A 12-year-old girl developed simple partial motor and sensory seizures due to a right perirolandic astrocytoma. Subdural EEG recording and functional stimulation disclosed close correlation between EEG-clinical manifestations of focal seizures and functional responses to cortical stimulation. This case supports the idea that responses in the perirolandic area to endogenous epileptogenic activity and to cortical stimulation reflect common underlying physiologic mechanisms.

Dopaminergic receptors linked to adenylate cyclase in human cerebromicrovascular endothelium

Cultured endothelium derived from three fractions of human cerebral microvessels was used to characterize dopamine (DA) receptors linked to adenylate cyclase activity. DA or D1 agonist, (+/-)-SKF-82958 hydrobromide, stimulated endothelial cyclic AMP formation in a dose-dependent manner. The selective D1 antagonist, (+/-)SCH-23390, inhibited in a dose-dependent manner the production of cyclic AMP induced by DA. The affinity for the D1 receptor appeared to be greater in endothelium derived from large and small microvessels than from capillaries. Cholera toxin ADP-ribosylation of Gs proteins abolished the DA stimulatory effect on endothelial adenylate cyclase, whereas pertussis toxin ADP-ribosylation enhanced the DA-inducible formation, indicating the presence of both D1 and D2 receptors. Agonists of alpha 1-adrenergic receptors (phenylephrine, 6-fluoronorepinephrine) or serotonin (5-HT), which stimulated the production of cyclic AMP, had no additive effect on DA-stimulated cyclic AMP formation. Incubation of these agents with DA produced the same or lower levels of cyclic AMP as compared to that formed by DA alone. The effect of alpha 1-adrenergic agonists or 5-HT on DA production of cyclic AMP was partially prevented by the D2 antagonist, S(-)-sulpiride, or ketanserin (5-HT2 greater than alpha 1 greater than H1 antagonists), respectively. These findings represent the first demonstration of D1- (stimulatory) and D2- (inhibitory) receptors linked to adenylate cyclase in microvascular endothelium derived from human brain. The data also indicate that dopaminergic receptors can interact with either alpha 1-adrenergic or or 5-HT receptors in endothelium on the adenylate cyclase level.(ABSTRACT TRUNCATED AT 250 WORDS)

Application of gadolinium-DTPA magnetic resonance imaging for detection of a filum terminale myxopapillary ependymoma allowing successful surgical resection

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Multifocal independent epileptiform discharges in children: ictal correlates and surgical therapy

We obtained continuous EEG/video recordings on four children who had the interictal EEG pattern of multifocal independent epileptiform discharges (MIED). The prominent feature of their evaluation was the evidence that their clinical seizures appeared to be of focal origin; 42/44 seizures were manifested by "fencing postures." Three patients subsequently underwent epilepsy surgery: one focal resection of superior frontal-parietal cortex and two hemidecorticectomies. Seizure control improved in all three patients, and one patient is now seizure-free. Our patients differ from those previously reported in that they had a predominance of tonic seizures and had no history of infantile spasms or Lennox-Gastaut syndrome. Some patients, such as ours, with MIED may have clinical seizures of more focal origin than might be expected from their interictal EEG and, therefore, may benefit from resective epilepsy surgery.

Stereotactic brain biopsy in the diagnosis of malignant lymphoma

Fifteen patients with cerebral involvement by malignant non-Hodgkin's lymphoma were identified, among more than 200 patients who underwent stereotactic biopsy at The Johns Hopkins Hospital. All but one of these cases were diagnosed accurately by the stereotactic biopsy procedure. In 12 of 14 patients, the material was adequate to classify the lymphoma according to the Working Formulation. Because all but one of the lesions were intermediate or high-grade neoplasms, a diagnosis of lymphoma was often possible by conventional light microscopic examination alone. Monotypic light chain expression was demonstrated by immunohistochemical techniques in six patients, and positivity for B-cell markers was observed in an additional case. In one instance, two stereotactic biopsy specimens were interpreted as being suggestive of lymphoma, but necrosis and inflammation prevented a definitive diagnosis. Nine patients had no known risk factors for cerebral lymphoma, and the diagnosis often was unsuspected clinically.

A cellist with arm pain: thermal asymmetry in scalenus anticus syndrome

We report on a cellist with pain and coldness of the upper extremity. Abnormal thermographic studies were instrumental in uncovering intermittent compression of the subclavian artery, and this prompted us to study the effects of cello playing on skin temperature asymmetry. Temperature asymmetry was defined as the temperature difference (delta-T) from one hand to the other. In 57 controls, mean delta-T at rest was .309 +/- .254C. Exercising the upper extremities by prolonged elbow flexion or by movements mimicking cello playing in controls did not significantly affect delta-T. In our patient, delta-T was ten times control (3.6C). Angiography showed extrinsic compression of the subclavian artery occurring only after cello playing; sympathetic ganglion block relieved the pain. Our patient's abnormal skin temperature may have reflected sympathetic vasomotor hyperactivity. Intermittent neurovascular compression and sympathetic hyperactivity appear to be factors in scalenus anticus syndrome.

Characterization of the basal temporal language area in patients with left temporal lobe epilepsy

We evaluated 5 consecutive patients with subdural grid electrodes (including placement over the left basal temporal region) for focal resections for control of intractable epilepsy. All 5 had language dysfunction when we performed cortical stimulation over the basal temporal region (the inferior temporal gyrus, the parahippocampal gyrus) using a systematic battery of language tests. The area in which language interference could be produced began from at least 11 to 35 mm posterior to the temporal tip and ended at least 39 to 74 mm posterior to the temporal tip. The most consistently impaired language tasks were spontaneous speech and passage reading, but there was impairment of all language functions tested in some patients. Language deficits after dominant temporal lobectomy may result from resection of this area.

Parameters for direct cortical electrical stimulation in the human: histopathologic confirmation

Safe parameters for electrical cortical stimulation in humans are difficult to estimate from the animal experimental literature. We therefore examined the light microscopic histology at a total of 11 sites of direct subdural electrical stimulation, taken as part of anterior temporal lobectomies in 3 patients. Stimulations had been done through 3.175 mm diameter electrodes, with 0.3 msec square wave pulses of alternating polarity at 50 pulses/sec. In 2 patients, one site each had been used as a common reference for stimulation, receiving over 251 stimulation trials, most of 2-5 sec duration, at currents of 12.5-15.0 mA, 1 day prior to resection. The maximum charge per phase was 4.0-4.4 microC; the maximum charge density was 52-57 microC per geometric cm2 per pulse at the electrode surfaces. Comparison of hematoxylin and eosin, periodic acid-Schiff, and cresyl violet-stained material from the electrode sites with that from other regions did not show any histologic abnormalities attributable to the electrical stimulation. The relatively brief and intermittent periods utilized for human stimulation testing do not appear to cause structural damage at the light microscopic level at charge densities that exceed the threshold for damage established in animal studies with more continuous, chronic stimulation schedules.

[PET assessment of myocardial viability with glucose loading and fasting FDG images]

Positron emission tomography (PET) offers the potential capability of evaluating tissue viability. We have studied the changes of myocardial F-18 deoxyglucose (FDG) uptake with glucose loading. In a fasting state (for at least 5 hours) and in a glucose loading state (50 g glucose orally one hour before the study) FDG (74-148 MBq) PET studies were performed for 50-60 minutes in 3 cases. 2 were subjects with anterior myocardial infarction (MI) including one with a ventricular aneurysm (case 1), one with a recent MI (case 2). One was a subject of aortic valvular disease without coronary lesions (case 3). Arterial input function (Ca(t)) and myocardial activity (Cm(t)) were derived from the regions of interest (ROI) on the left atrium and from multiple ROI's circumferentially about the myocardium. Net extraction, FU (Fractional Uptake) = Cm(T)/integral of T0 Ca(t)dt, were calculated. Normal segment (N) showed an increase in FU with glucose loading, but the ischemic segment showed no increase (case 1) or a lower increase (case 2) relative to N. This study shows that the increase in FU with glucose loading suggests the persistence of viable myocardium. In conclusion, myocardial viability may be evaluated by comparing FDG images in a glucose loading state with those in a fasting state.

[Estimation of the reticuloendothelial function by positron emission computed tomography (PET) study in chronic liver disease]

We have developed a new liver scanning agent (Ga-68 human serum albumin microspheres) in a convenient kit for use in positron emission computed tomography (PET). In this study, this scanning agent was evaluated for clinical usefulness as a function test for the reticuloendothelial system. A dose of 5 micrograms/kg (1-2 mCi) of Ga-68 microspheres was injected intravenously to 25 patients, 11 with chronic hepatitis and 14 with liver cirrhosis, and 5 normal volunteers for PET imaging of the liver and spleen using HEADTONE-III (SET 120W). The volumes of the liver and the spleen and the uptakes of Ga-68 microspheres were calculated as an index of the reticuloendothelial system function. In liver cirrhosis the liver volume estimated by PET was decreased and the spleen volume was increased. Both the liver uptake rate and differential absorption ratio (DAR) of the radioactivity were decreased corresponding with the degree of chronic liver disease. The spleen uptake rate was increased with progression of chronic liver diseases, but there was no difference in DAR between normal volunteers and patients with chronic liver disease. it was concluded that PET using Ga-68 microspheres is useful in the evaluation of the function of the reticuloendothelial system.

The role of arachidonic acid and oxygen radicals on cerebromicrovascular endothelial permeability

Arachidonic acid release from tissue membranes and/or formation of free radical species have been considered to affect blood-brain barrier permeability and formation of brain oedema. To determine whether exogenous arachidonic acid or H2O2 may alter blood-brain barrier permeability, we examined their effect on cultured endothelium derived from cerebral microvessels of human and animals. Release of 51Cr from labeled endothelium exposed to these substance was used as a main marker for the assessment of endothelial injury. The results of these studies indicate that endothelial cells (EC) are susceptible to exogenous arachidonic acid or H2O2 insult irrespective of their origin. However human endothelial cells are less affected than animal EC by H2O2-generated systems. The findings suggest that a disturbance of the existing balance between the endogenous antioxidant properties of EC and exogenous oxidant leads to EC injury.

Resection of the epileptogenic area in critical cortex with the aid of a subdural electrode grid

Electrode grids were implanted subdurally in 28 patients with epilepsy. In 16 of the 28 patients, an epileptogenic area was located in the speech-dominant left temporal lobe. Recordings made with the grid revealed that the epileptogenic areas in the patients varied widely in extent: the area was confined within the first 10 mm of the temporal lobe in some patients or it was scattered throughout the entire anterior to posterior 80-mm extend in others. Resection of the epileptogenic area was adjusted accordingly in each case. In 6 of 16 patients who were left-hemisphere-dominant for language, up to 55-80 mm from the tip of the temporal lobe was removed, a measure that exceeds the conventional limit of 50 mm from the tip of the dominant hemisphere. In the remaining 12 of the 28 patients, epileptogenic areas were located in a combination of several lobes. In 7 of these 12 patients, the epileptogenic area encompassed the rolandic area; it was removed without deficit in 4 patients and with expected deficit in 3. Of the latter 3 patients, 1 patient underwent hemispherectomy, and a large portion of the epileptogenic rolandic cortex in the frontal and parietal lobes was removed from the other 2. There were 2 cases of grid-related infection, which cleared with antibiotic treatment; there were no lasting complications of grid implantation in any patient. There was no mortality. Electroencephalographic recording and functional mapping using subdural electrode grids allow a tailored, maximal resection of epileptogenic tissue with minimal injury to critical cortex.

Compression syndromes due to hypertrophic nerve roots in hereditary motor sensory neuropathy type I

Three patients with hereditary motor sensory neuropathy type I developed neurologic deficits attributable to hypertrophic nerve roots. Compression of the cervical spinal cord by enlarged nerve roots occurred in our index patient. Multilevel decompressive laminectomies relieved the myelopathy. An unrelated patient who had syncope precipitated by neck rotation had hypertrophied nerve roots that eroded into the transverse foramina in juxtaposition to the vertebral arteries. In a 3rd patient, compression of hypertrophied nerve roots within the thecal sac and neural foramina was associated with spinal claudication and radiculopathy, respectively.

Intraoperative CT-guided serial microbiopsy of brain lesions and concomitant use of CT air and angiographic studies

The value of step-by-step confirmation of the location of the brain biopsy probe is demonstrated, using serial CT scanning to confirm the exact source of the sample tissue. Concomitant use of CT angiography and a CT air study makes possible the biopsy of small areas and of areas near major cerebral vessels, as well as of lesions near critical areas like the optic chiasma, basal ganglia, midbrain, and other complex lesions. The pathologist on-line examination of the CT-confirmed serial samples enables the surgeon to obtain the most informative tissue for the ultimate histopathological diagnosis. Our experience with the technique is illustrated by examples of its application in some complex cases.

Placebo responses to medical device therapy for pain

Placebo response to a functionless machine was tested in 58 patients with chronic pain. Thirteen discontinued treatment before the planned trials were complete: 5 did so because sham therapy worsened their pain. Forty-five patients completed three trials of treatment with a magnetic device, one trial of which was a sham. Thirteen percent of patients undergoing sham therapy experienced relief of pain, improved range of motion, and decrease in muscle spasm. Eleven percent of the sham trials resulted in significant increase in pain. The placebo/nocebo response to sham therapy with a device is similar to that previously reported for prolonged drug treatment, but is lower than the placebo rate for short-term medication trials.

Microphysiological recordings at CT gantry site during stereotactic thalamotomy

Neural unit recording was performed during CT-guided stereotactic thalamotomy in 2 patients referred for severe cerebellar ataxia and dysmetric movements. Periodic CT scanning was performed during the recording in order to verify probe location and trajectory. Our experience with electrophysiological recordings at the CT gantry site demonstrates the feasibility of acquiring satisfactory neural unit recordings in spite of the high-voltage environment.

Electrophysiological recordings during spinal surgery

Experience with electrophysiological monitoring during surgery of the spinal vertebrae and spinal cord is reviewed. The cerebral somatosensory evoked potential (CSEP) is used to monitor spinal cord conductivity during mechanical manipulation of the vertebrae, most commonly during correction of the curvature of the spine. Abnormal CSEPs were recorded in 11 out of approximately 700 cases of scoliosis surgery. During percutaneous cordotomy, intracord evoked and spontaneous potentials are recorded in order to identify the cord structure. Experiment models are also discussed.

Quantification of thermal asymmetry. Part 1: Normal values and reproducibility

The use of thermography in evaluating nerve injury is based on the presence of temperature asymmetries between the involved area of innervation and the corresponding area on the opposite side of the body. However, interpretation of the thermographic image has been troubled by subjectivity. This paper describes a computer-calculated method of collecting data that eliminates subjective biases. Comprehensive normative data are presented on the degree of thermal asymmetry in the human body. The degree of thermal asymmetry between opposite sides of the body (delta T) is very small. For example, the value of delta T for the forehead (mean +/- standard deviation) was 0.18 degree +/- 0.18 degree C, for the leg it was 0.27 degree +/- 0.2 degree C, and for the foot it was 0.38 degree +/- 0.31 degree C. These values were reproducible in both short- and long-term follow-up measurements over a period of 5 years. The delta T's reported here were obtained from 40 matched regions of the body surface of 90 asymptomatic normal individuals. These values can be used as a standard in assessment of sympathetic nerve function, and the degree of asymmetry is a quantifiable indicator of dysfunction.

Quantification of thermal asymmetry. Part 2: Application in low-back pain and sciatica

Temperature differences between the lower extremities were measured using a computerized thermometric scanning system in order to compare the degree of thermal asymmetry in 144 patients with low-back pain. The patients displayed highly significant thermal asymmetries, with the involved limb being cooler (p less than 0.001). When asymmetries exceeded 1 standard deviation from the mean temperature of homologous regions measured in 90 normal control subjects, the positive predictive value of thermometry in detecting root impingement was 94.7% and the specificity was 87.5%. These values indicate that calculation of temperature asymmetry is particularly effective in evaluating reported pain in psychosocially affected patient populations in whom the chance of positive myelography or impaired root function is low. In this group of patients, thermometric study provides physicians with important information for proper decision making. The test can be performed to avoid more invasive and probably less revealing diagnostic or exploratory surgical procedures.

Spinal cord monitoring during posterior spinal instrumentation and fusion

Two hundred seventy-five consecutive patients who were treated by posterior spinal instrumentation and fusion with iliac crest bone graft were intraoperatively monitored using cortical somatosensory-evoked potentials without a planned wake-up test. The monitoring was performed using a TECA TE-4 system that included an electromyograph, a nerve stimulator, and a digital averager. Intraoperatively, six patients (2%) demonstrated significant changes in evoked potentials, consisting of either marked increase in latency or a loss of wave form during instrumentation of the spine. The instrumentation was removed immediately and the evoked potentials returned to base-line tracing within 15-30 minutes in all six cases. Five patients who had instruments refitted to maintain a lesser amount of correction had no subsequent change in the evoked potentials. One patient had spinal fusion without instrumentation. Postoperatively, all patients are neurologically normal.