Cortico-cerebellar connectivity underlying motor control in chronic post-stroke individuals.

The robust, reciprocal anatomical connections between the cerebellum and contralateral sensorimotor cerebral hemisphere underscores the strong physiological interdependence between these two regions in relation to human behavior. Previous studies have shown that damage to sensorimotor cortex can result in a lasting reduction of cerebellar metabolism, the magnitude of which has been linked to poor rehabilitative outcomes. A better understanding of movement-related cerebellar physiology as well as cortico-cerebellar coherence (CCC) in the chronic, post-stroke state may be key to developing novel neuromodulatory techniques that promote upper limb motor rehabilitation. As a part of the first in-human phase-I trial investigating the effects of deep brain stimulation of the cerebellar dentate nucleus (DN) on chronic, post-stroke motor rehabilitation, we collected invasive recordings from DN and scalp EEG in subjects (both sexes) with middle cerebral artery stroke during a visuo-motor tracking task. We investigated the excitability of ipsilesional cortex, DN and the their interaction as a function of motor impairment and performance. Our results indicate that 1) event-related oscillations in the ipsilesional cortex and DN were significantly correlated at movement onset in the low-ß band, with moderately and severely impaired subjects showing desynchronization and synchronization, respectively. 2) Significant CCC was observed during isometric 'hold' period in the low-ß band, which was critical for maintaining task accuracy. Our findings support a strong coupling between ipsilesional cortex and DN in the low-ß band during motor control across all impairment levels which encourages the exploitation of the cerebello-thalamo-cortical pathway as a neuromodulation target to promote rehabilitation.Significance Statement:Cerebral infarct due to stroke can lead to lasting reduction in cerebellar metabolism resulting in poor rehabilitative outcomes. Thorough investigation of the cerebellar electrophysiology as well as cortico-cerebellar connectivity in humans that could provide key insights to facilitate development of novel neuromodulatory technologies, has been lacking. As a part of the first in-human phase-I trial investigating deep brain stimulation of the cerebellar dentate nucleus (DN) for chronic, post-stroke motor rehabilitation, we collected invasive recordings from DN and scalp EEG while stroke patients performed a motor task. Our data indicate strong coupling between ipsilesional sensorimotor cortex and DN in the low-ß band across all impairment levels encouraging the exploration of electrical stimulation of the DN.

Deep brain stimulation of the ventral internal capsule/ventral striatum for obsessive-compulsive disorder: worldwide experience.

Psychiatric neurosurgery teams in the United States and Europe have studied deep brain stimulation (DBS) of the ventral anterior limb of the internal capsule and adjacent ventral striatum (VC/VS) for severe and highly treatment-resistant obsessive-compulsive disorder. Four groups have collaborated most closely, in small-scale studies, over the past 8 years. First to begin was Leuven/Antwerp, followed by Butler Hospital/Brown Medical School, the Cleveland Clinic and most recently the University of Florida. These centers used comparable patient selection criteria and surgical targeting. Targeting, but not selection, evolved during this period. Here, we present combined long-term results of those studies, which reveal clinically significant symptom reductions and functional improvement in about two-thirds of patients. DBS was well tolerated overall and adverse effects were overwhelmingly transient. Results generally improved for patients implanted more recently, suggesting a 'learning curve' both within and across centers. This is well known from the development of DBS for movement disorders. The main factor accounting for these gains appears to be the refinement of the implantation site. Initially, an anterior-posterior location based on anterior capsulotomy lesions was used. In an attempt to improve results, more posterior sites were investigated resulting in the current target, at the junction of the anterior capsule, anterior commissure and posterior ventral striatum. Clinical results suggest that neural networks relevant to therapeutic improvement might be modulated more effectively at a more posterior target. Taken together, these data show that the procedure can be successfully implemented by dedicated interdisciplinary teams, and support its therapeutic promise.

Retinoblastoma protein contains a C-terminal motif that targets it for phosphorylation by cyclin-cdk complexes.

Stable association of certain proteins, such as E2F1 and p21, with cyclin-cdk2 complexes is dependent upon a conserved cyclin-cdk2 binding motif that contains the core sequence ZRXL, where Z and X are usually basic. In vitro phosphorylation of the retinoblastoma tumor suppressor protein, pRB, by cyclin A-cdk2 and cyclin E-cdk2 was inhibited by a short peptide spanning the cyclin-cdk2 binding motif present in E2F1. Examination of the pRB C terminus revealed that it contained sequence elements related to ZRXL. Site-directed mutagenesis of one of these sequences, beginning at residue 870, impaired the phosphorylation of pRB in vitro. A synthetic peptide spanning this sequence also inhibited the phosphorylation of pRB in vitro. pRB C-terminal truncation mutants lacking this sequence were hypophosphorylated in vitro and in vivo despite the presence of intact cyclin-cdk phosphoacceptor sites. Phosphorylation of such mutants was restored by fusion to the ZRXL-like motif derived from pRB or to the ZRXL motifs from E2F1 or p21. Phospho-site-specific antibodies revealed that certain phosphoacceptor sites strictly required a C-terminal ZRXL motif whereas at least one site did not. Furthermore, this residual phosphorylation was sufficient to inactivate pRB in vivo, implying that there are additional mechanisms for directing cyclin-cdk complexes to pRB. Thus, the C terminus of pRB contains a cyclin-cdk interaction motif of the type found in E2F1 and p21 that enables it to be recognized and phosphorylated by cyclin-cdk complexes.

Retention time for corticosteroid-sparing systemic immunosuppressive agents in patients with inflammatory eye disease.

BACKGROUND: Multiple immunosuppressive drugs have been used to manage inflammatory eye disease when control cannot be achieved by corticosteroid alone. However, although clinical studies support the effectiveness of most of these agents, comparative studies have not been undertaken. Retention time, a measure of the duration of treatment with any given drug, is a crude indicator of drug effectiveness and tolerability that facilitates such a comparison. The retention time was compared for corticosteroid-sparing immunosuppressive agents in patients attending our tertiary referral inflammatory eye disease clinic. METHODS: The clinical records of all patients attending an inflammatory eye disease clinic at the Casey Eye Institute over a 1-year period (2003) were reviewed. From these records, we collected the following clinical data: age; sex; ocular diagnosis; and use of steroid-sparing systemic immunosuppression, including drugs, duration of treatment and, if ceased, reasons for cessation. Cox regression analysis, adjusted for clustering, was used to compare other drugs against methotrexate. RESULTS: 107 of 302 (35%) patients seen at the inflammatory eye disease clinic in 2003 had a total of 193 current or past prescriptions for systemic steroid-sparing immunosuppressive agents. The treated group, most of whom had uveitis, included 32 men and 75 women, aged 5-86 years. Most commonly prescribed were methotrexate (66 uses, 34%), ciclosporin (37 uses, 19%), azathioprine (26 uses, 13%), mycophenolate mofetil (22 uses, 11%) and cyclophosphamide (15 uses, 8%). Patients were retained significantly less on ciclosporin (p = 0.004), azathioprine (p = 0.04), mycophenolate mofetil (p = 0.04) and cyclophosphamide (p<0.001) compared with methotrexate. Reasons for cessation included adverse events, lack of effectiveness, success or remission, cost and desire for fertility. CONCLUSIONS: In patients with inflammatory eye disease, methotrexate may offer a superior combination of effectiveness and tolerability over other commonly used corticosteroid-sparing immunosuppressive agents. In this study, there was a twofold risk of not being retained on azathioprine, mycophenolate mofetil and ciclosporin and a fourfold risk of not being retained on cyclophosphamide compared with methotrexate.

Physiological changes in the pallidum in a progressive model of Parkinson's disease: Are oscillations enough?

Neurophysiological changes in the basal ganglia thalamo-cortical circuit associated with the development of parkinsonian motor signs remain poorly understood. Theoretical models have ranged from those emphasizing changes in mean discharge rate to increased oscillatory activity within the beta range. The present study characterized neuronal activity within and across the internal and external segments of the globus pallidus as a function of motor severity using a staged, progressively severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinsonism in three rhesus monkeys. An increase in coherence between neuronal pairs across the external and internal globus pallidus was present in multiple frequency bands in the parkinsonian state; both the peak frequency of oscillatory coherence and the variability were reduced in the parkinsonian state. The incidence of 8-20Hz oscillatory activity in the internal globus pallidus increased with the progression of the disease when pooling the data across the three animals; however it did not correlate with motor severity when assessed individually and increased progressively in only one of three animals. No systematic relationship between mean discharge rates or the incidence or structure of bursting activity and motor severity was observed. These data suggest that exaggerated coupling across pallidal segments contribute to the development of the parkinsonian state by inducing an exaggerated level of synchrony and loss of focusing within the basal ganglia. These data further point to the lack of a defined relationship between rate changes, the mere presence of oscillatory activity in the beta range and bursting activity in the basal ganglia to the motor signs of Parkinson's disease.

Performance on the PD test battery by relatives of patients with progressive supranuclear palsy.

OBJECTIVE: To determine whether there is a greater prevalence of asymptomatic first-degree relatives (FDR) of patients with progressive supranuclear palsy (PSP) performing abnormally on the PD test battery (PD Battery) compared to sex- and age-matched normal control (NC) individuals. The PD Battery incorporates tests of motor function, olfaction, and mood. It has high specificity and sensitivity in distinguishing mildly affected PD patients from NC individuals in previous studies. METHODS: This test battery and regression analysis-derived scoring equations were applied to asymptomatic FDR. RESULTS: Twenty-three FDR and 23 NC individuals were tested. Of the FDR, 39% scored in the abnormal range, whereas none of the NC individuals achieved abnormal scores. This difference was significant. Further analysis demonstrated that the two groups differed significantly on a measure of simple reaction time. CONCLUSIONS: The proportion of FDR who demonstrated abnormal performance on the PD Battery was greater than NC individuals. Thus, the PD Battery may detect the asymptomatic carrier state or risk for PSP or a subclinical effect of a shared environmental exposure.

Abnormal performance on the PD test battery by asymptomatic first-degree relatives.

OBJECTIVE: To determine whether a sensitive and specific battery of tests (PD Battery) could identify a subset of asymptomatic first-degree relatives (FDRs) of PD patients who were significantly more impaired than age-matched normal control (NC) subjects. The PD Battery incorporates tests of motor function, olfaction, and mood. In previous studies, it has shown high specificity and sensitivity in distinguishing mildly affected PD patients from NC subjects. METHODS: The PD Battery and regression analysis-derived scoring equations were applied to asymptomatic FDRs. RESULTS: Eighty FDRs and 100 NC subjects were tested. Of the FDRs, 22.5% scored in the abnormal range, and 9% of NC subjects had abnormal scores. This difference was statistically significant. Further analysis demonstrated that FDRs with abnormal scores on the PD Battery differed on all three components of the test battery from FDRs who had normal scores. Among the sons and daughters whose scores were abnormal, there was a much higher prevalence of the affected parent being the father. CONCLUSIONS: The proportion of FDRs who demonstrated abnormal performance on the PD Battery was greater than that of NC subjects. Thus, the PD Battery may detect the asymptomatic carrier state or risk for PD. Sons and daughters whose scores were in the abnormal range were more likely to have fathers with PD.

Chronic thalamic stimulation for the tremor of multiple sclerosis.

The authors studied chronic high-frequency stimulation of the ventral intermediate nucleus of the thalamus (Vim) for controlling upper extremity tremor in patients with MS using MRI, CT, and microelectrode recordings and stimulation to locate optimal target sites. Fifteen patients underwent surgery. All patients had reduced tremor but developed tolerance requiring repeated programming of the stimulator. Benefit at optimal stimulator settings was maintained. Two patients experienced complications: intracerebral hematoma and MS exacerbation. Chronic high-frequency stimulation of Vim provides tremor reduction if patients have access to frequent stimulator adjustments. This surgery is relatively safe.

"Neutral allografts"--lack of allogeneic stimulation by cultured human cells expressing MHC class I and class II antigens.

Cultured human dermal fibroblasts, smooth muscle cells, epidermal cells and endothelial cells were tested for immunogenicity in an in vitro allostimulation assay. Gamma interferon was used to induce MHC class II expression, since these cells constitutively express class I but not class II antigens. In contrast to human dermal fibroblasts, smooth muscle cells and epidermal cells, endothelial cells, were able to stimulate a significant proliferative response in normal allogeneic lymphocytes. Since ICAM-1 was also expressed on these cells, this inability to initiate allostimulation was probably not due to the absence of adhesion molecules. Addition of exogenous cytokines such as IL-1, IL-2, and TNF did not restore T cell proliferation in the test system. Therefore the inability of dermal fibroblasts, smooth muscle cells, and epidermal cells to initiate significant allostimulation was also not due to lack of cytokine production. It appears that certain cells lack as-yet-undefined costimulatory factors required for their effective recognition as foreign. These results support the notion that cultured human fibroblasts, smooth muscle cells, and epidermal cells could serve as building blocks of engineered "neutral allografts" for use across MHC barriers.

Deep brain stimulation in epilepsy.

Since the pioneering studies of Cooper et al. to influence epilepsy by cerebellar stimulation, numerous attempts have been made to reduce seizure frequency by stimulation of deep brain structures. Evidence from experimental animal studies suggests the existence of a nigral control of the epilepsy system. It is hypothesized that the dorsal midbrain anticonvulsant zone in the superior colliculi is under inhibitory control of efferents from the substantia nigra pars reticulata. Inhibition of the subthalamic nucleus (STN) could release the inhibitory effect of the substantia nigra pars reticulata on the dorsal midbrain anticonvulsant zone and thus activate the latter, raising the seizure threshold. Modulation of the seizure threshold by stimulation of deep brain structures-in particular, of the STN-is a promising future treatment option for patients with pharmacologically intractable epilepsy. Experimental studies supporting the existence of the nigral control of epilepsy system and preliminary results of STN stimulation in animals and humans are reviewed, and alternative mechanisms of seizure suppression by STN stimulation are discussed.

Calcium carbonate apatite deposition in the cervical spine with associated vertebral destruction. Case report.

This 52-year-old woman developed crystal deposition disease involving the cervical vertebrae. She presented with symptomatic spinal cord compression secondary to extensive calcified lesions in the posterior elements of the cervical spine. Surgical decompression with posterior fusion was performed. Histological examination showed hardened deposits of calcium carbonate involving the soft tissue, and dissolution of the vertebral bone trabeculae. There was no inflammatory response to these deposits. One year postoperatively the patient developed severe pulmonary disease associated with the collagen-vascular disorder, scleroderma (calcinosis, Raynaud's phenomenon, esophageal hypomotility, sclerodactyly, and telangiectasia [CREST] syndrome). Calcium carbonate deposition disease represents an unusual clinical entity that is possibly associated with scleroderma or other collagen-vascular diseases, and it is distinct from ligamentum flavum calcification, calcium pyrophosphate deposition disease, and hydroxyapatite deposition disease.

Mechanisms of deep brain stimulation and future technical developments.

Possible mechanisms underlying the therapeutic effect of deep brain stimulation (DBS) are reviewed, particularly the notion that DBS is inhibitory. Computer simulations are described that model the effect of different frequencies and regularity of neuronal activity (target neuron), either spontaneous or stimulated, on information transfer between two other neurons. Most simulations resulted in a loss of information. These were the least with high frequency and regular activity or stimulation of the target neuron with regularity having the least deleterious effect on information transfer. The simulations suggest that irregular activity in neurons converging with other neurons can result in a loss of information transfer. This may explain why increased irregularity in globus pallidus activity associated with Parkinson's disease, dystonia and hemiballismus may result in symptoms. Further, the therapeutic effect of DBS may be due to driving neurons at higher and perhaps more importantly, regular frequencies. There were simulations in which information transfer was augmented suggesting the presence of stochastic resonance. This most often occurred with low frequency activity in the target neuron. It is hypothesized that low frequency activity, either spontaneous or stimulated, could account for involuntary movements, including tremor. Future directions and challenges to DBS are also discussed.

Counter immunoelectrophoresis in the diagnosis and serological surveillance of swine vesicular disease.

A comparison of the counter immunoelectrophoresis (CIEP) test for swine vesicular disease with serum neutralisation and double immunodiffusion is reported here. Two groups of sera were used in the comparison: one group (908 sera) was tested blind by CIEP and the other group (778 sera) comprised field samples from infected and suspect premises submitted routinely for swine vesicular disease confirmation. The CIEP test proved simple to perform and gave results within two hours. It was very economic in the use of reagents and its sensitivity, though less than that of the serum neutralisation test, compared favourably with the sensitivity of the double immunodiffusion test. No false positive results were detected out of the 1686 sera tested.

Male and female Fmr1 knockout mice on C57 albino background exhibit spatial learning and memory impairments.

Impaired spatial learning is a prominent deficit in fragile X syndrome (FXS). Previous studies using the Fmr1 knockout (KO) mouse model of FXS have not consistently reported a deficit in spatial learning. Fmr1 KO mice bred onto an albino C57BL/6J-Tyr(c-Brd) background showed significant deficits in several primary measures of performance during place navigation and probe trials in the Morris water maze. Fmr1 KO mice were also impaired during a serial reversal version of the water maze task. We examined fear conditioning as an additional cognitive screen. Knockout mice exhibited contextual memory deficits when trained with unsignaled shocks; however, deficits were not found in a separate group of KO mice trained with signaled shocks. No potentially confounding genotypic differences in locomotor activity were observed. A decreased anxiety-like profile was apparent in the open field, as others have noted, and also in the platform test. Also as previously reported, startle reactivity to loud auditory stimuli was decreased, prepulse inhibition and social interaction increased in KO mice. Female Fmr1 KO mice were tested along with male KO mice in all assays, except for social interaction. The female and male KO exhibited very similar impairments indicating that sex does not generally drive the behavioral symptoms of the disorder. Our results suggest that procedural factors, such as the use of albino mice, may help to reliably detect spatial learning and memory impairments in both sexes of Fmr1 KO mice, making it more useful for understanding FXS and a platform for evaluating potential therapeutics.