Regional structural abnormalities in thalamus in idiopathic cervical dystonia.

BACKGROUND: The thalamus has a central role in the pathophysiology of idiopathic cervical dystonia (iCD); however, the nature of alterations occurring within this structure remain largely elusive. Using a structural magnetic resonance imaging (MRI) approach, we examined whether abnormalities differ across thalamic subregions/nuclei in patients with iCD. METHODS: Structural MRI data were collected from 37 patients with iCD and 37 healthy controls (HCs). Automatic parcellation of 25 thalamic nuclei in each hemisphere was performed based on the FreeSurfer program. Differences in thalamic nuclei volumes between groups and their relationships with clinical information were analysed in patients with iCD. RESULTS: Compared to HCs, a significant reduction in thalamic nuclei volume primarily in central medial, centromedian, lateral geniculate, medial geniculate, medial ventral, paracentral, parafascicular, paratenial, and ventromedial nuclei was found in patients with iCD (P < 0.05, false discovery rate corrected). However, no statistically significant correlations were observed between altered thalamic nuclei volumes and clinical characteristics in iCD group. CONCLUSION: This study highlights the neurobiological mechanisms of iCD related to thalamic volume changes.

Topological alterations in white matter anatomical networks in cervical dystonia.

BACKGROUND: Accumulating neuroimaging evidence indicates that patients with cervical dystonia (CD) have changes in the cortico-subcortical white matter (WM) bundle. However, whether these patients' WM structural networks undergo reorganization remains largely unclear. We aimed to investigate topological changes in large-scale WM structural networks in patients with CD compared to healthy controls (HCs), and explore the network changes associated with clinical manifestations. METHODS: Diffusion tensor imaging (DTI) was conducted in 30 patients with CD and 30 HCs, and WM network construction was based on the BNA-246 atlas and deterministic tractography. Based on the graph theoretical analysis, global and local topological properties were calculated and compared between patients with CD and HCs. Then, the AAL-90 atlas was used for the reproducibility analyses. In addition, the relationship between abnormal topological properties and clinical characteristics was analyzed. RESULTS: Compared with HCs, patients with CD showed changes in network segregation and resilience, characterized by increased local efficiency and assortativity, respectively. In addition, a significant decrease of network strength was also found in patients with CD relative to HCs. Validation analyses using the AAL-90 atlas similarly showed increased assortativity and network strength in patients with CD. No significant correlations were found between altered network properties and clinical characteristics in patients with CD. CONCLUSION: Our findings show that reorganization of the large-scale WM structural network exists in patients with CD. However, this reorganization is attributed to dystonia-specific abnormalities or hyperkinetic movements that need further identification.

Proprioceptive Modulation of Pallidal Physiology in Cervical Dystonia.

BACKGROUND: There is a growing body of evidence suggesting that botulinum toxin can alter proprioceptive feedback and modulate the muscle-spindle output for the treatment of dystonia. However, the mechanism for this modulation remains unclear. METHODS: We conducted a study involving 17 patients with cervical dystonia (CD), seven of whom had prominent CD and 10 with generalized dystonia (GD) along with CD. We investigated the effects of neck vibration, a form of proprioceptive modulation, on spontaneous single-neuron responses and local field potentials (LFPs) recorded from the globus pallidum externus (GPe) and internus (GPi). RESULTS: Our findings demonstrated that neck vibration notably increased the regularity of neck-sensitive GPi neurons in focal CD patients. Additionally, in patients with GD and CD, the vibration enhanced the firing regularity of non-neck-sensitive neurons. These effects on single-unit activity were also mirrored in ensemble responses measured through LFPs. Notably, the LFP modulation was particularly pronounced in areas populated with burst neurons compared to pause or tonic cells. CONCLUSION: The results from our study emphasize the significance of burst neurons in the pathogenesis of dystonia and in the efficacy of proprioceptive modulation for its treatment. Moreover, we observed that the effects of vibration on focal CD were prominent in the α band LFP, indicating modulation of pallido-cerebellar connectivity. Moreover, the pallidal effects of vibration in GD with CD involved modulation of cerebro-pallidal θ band connectivity. Our analysis provides insight into how vibration-induced changes in pallidal activity are integrated into the downstream motor circuit. © 2023 International Parkinson and Movement Disorder Society.

Tremor-Dominant Cervical Dystonia: a Cerebellar Syndrome.

The objective of this study is to examine the role of the cerebellum in the tremor-dominant subtype of cervical dystonia (CD). CD patients with head tremor at onset (Tr-CD) were age- and sex-matched to CD patients without head tremor at onset (nTr-CD). All patients were evaluated for cerebellar disability using the Scale for the Assessment and Rating of Ataxia (SARA), gait variability using ProtoKinetics Zeno Walkway, and cerebellar volume analysis extracted from brain magnetic resonance imaging (MRI) using a semiquantitative scale. Compared to nTr-CD (n = 10, median age, 70.5 years), Tr-CD patients (n = 10, 71.5 years) exhibited higher median SARA scores (9 vs 7.5, p = 0.03) and greater median gait variability index (131 vs 124, p = 0.03). SARA scores inversely correlated with cerebellar volume in all patients (- 0.4, p = 0.04). Tr-CD patients exhibited greater superior vermian atrophy than nTr-CD patients (p = 0.01). Head tremor at onset heralds a CD subtype with prominent axial cerebellar disability and atrophy of the superior vermis of the cerebellum.

Benign paroxysmal torticollis: phenotype, natural history, and quality of life.

BACKGROUND: Benign paroxysmal torticollis (BPT) is characterized by attacks of head tilt associated with vomiting, irritability, and/or ataxia in early childhood. BPT is associated with migraine but risk factors are unknown. Impact on quality of life is also unknown. METHODS: Parents/caregivers of children with ongoing or resolved BPT participated in telephone interviews (n = 73). Those with ongoing BPT completed the Infant Toddler Quality of Life questionnaire (ITQoL). RESULTS: Median age of children at the time of interview was 2.9 years (range 0.25-23). BPT was ongoing in 52% (n = 38). Nineteen percent (n = 14) developed migraine (median age 9.25 years, range 2.5-23) and 63% (n = 46) developed another episodic syndrome associated with migraine. Proportion of patients who developed migraine was higher among those with certain migrainous symptoms during BPT attacks vs. those without: phonophobia (58 vs. 21%, p = 0.02), photophobia and phonophobia (55 vs. 23%, p = 0.05), and photophobia, phonophobia, and motion sensitivity (60 vs. 22%, p = 0.02). ITQoL results showed significant impact of BPT on quality of life. CONCLUSIONS: Children with BPT may develop migraine or other episodic syndromes associated with migraine. Presence of migrainous features during BPT episodes may increase likelihood of developing migraine. Though characterized as "benign," BPT can significantly impact children and families. IMPACT: Benign paroxysmal torticollis (BPT) is a rare condition of early childhood characterized by episodes of head tilt associated with vomiting, irritability, ataxia, pallor, and/or malaise. This cohort study describes the phenotypic spectrum of BPT, variable treatment, natural history and association with migraine, and impact on development and quality of life. Children with BPT may go on to develop migraine or episodic syndromes that may be associated with migraine; presence of migrainous features during attacks may increase odds of developing migraine. BPT can have significant impact on quality of life, demonstrated by findings from the Infant Toddler Quality of Life questionnaire.

Abnormal regional homogeneity and its relationship with symptom severity in cervical dystonia: a rest state fMRI study.

BACKGROUND: Although several brain networks play important roles in cervical dystonia (CD) patients, regional homogeneity (ReHo) changes in CD patients have not been clarified. We investigated to explore ReHo in CD patients at rest and analyzed its correlations with symptom severity as measured by Tsui scale. METHODS: A total of 19 CD patients and 21 gender-, age-, and education-matched healthy controls underwent fMRI scans at rest state. Data were analyzed by ReHo method. RESULTS: Patients showed increased ReHo in the right cerebellum crus I and decreased ReHo in the right superior medial prefrontal cortex (MPFC). Moreover, the right precentral gyrus, right insula, and bilateral middle cingulate gyrus also showed increased ReHo values. A significantly positive correlation was observed between ReHo value in the right cerebellum crus I and symptom severity (p < 0.05). CONCLUSIONS: Our investigation suggested abnormal ReHo existed in brain regions of the "pain matrix" and salience network (the right insula and bilateral middle cingulate gyrus), the motor network (the right precentral gyrus), the cerebellum and MPFC and further highlighted the significance of these networks in the pathology of CD.

Comparison of Clinical Findings of Congenital Muscular Torticollis Between Patients With and Without Sternocleidomastoid Lesions as Determined by Ultrasonography.

AIM: To compare clinical findings for patients with congenital muscular torticollis (CMT) between those with and without a sternocleidomastoid (SCM) lesion. METHODS: Medical records of 182 patients with CMT were retrospectively reviewed and the patients were divided into SCM lesion and nonlesion groups by ultrasonographic results. Intrauterine position, age, duration of therapy, rotation/tilting side, and the passive range of motion and angle of the neck were compared. RESULTS: There were 74 SCM lesion and 108 nonlesion cases. The mean age at the first visit was 55.3 days in the SCM lesion group and 146.6 days in the nonlesion group. The mean therapy time in the nonlesion group was 66.5 days, significantly shorter than for the SCM lesion group (117.5 d). Tilting and rotation of the head in the same direction was observed only in the nonlesion group (n=9, 8.3%). Rotational limitation of the affected muscle side was 22.6 degree in the SCM lesion and 3.6 degree in the nonlesion group, and the tilting limitation was 19.2 degree in the SCM lesion and 10.4 degree in the nonlesion group. CONCLUSIONS: The nonlesion group had a better prognosis with shorter treatment duration. This group was more limited in head tilting than in head rotation, and the pattern of head rotation/tilting in the same direction was observed only in this group. These findings suggest that pathophysiological mechanisms and clinical characteristics may differ between CMT patients with and without SCM lesions. LEVEL OF EVIDENCE: Level II-prognostic studies, retrospective study.

Pedunculopontine Nucleus Cholinergic Deficiency in Cervical Dystonia.

BACKGROUND: The etiology of cervical dystonia is unknown. Cholinergic abnormalities have been identified in dystonia animal models and human imaging studies. Some animal models have cholinergic neuronal loss in the striatum and increased acetylcholinesterase activity in the pedunculopontine nucleus. OBJECTIVES: The objective of this study was to determine the presence of cholinergic abnormalities in the putamen and pedunculopontine nucleus in cervical dystonia human brain donors. METHODS: Formalin-fixed brain tissues were obtained from 8 cervical dystonia and 7 age-matched control brains (controls). Pedunculopontine nucleus was available in only 6 cervical dystonia and 5 controls. Neurodegeneration was evaluated pathologically in the putamen, pedunculopontine nucleus, and other regions. Cholinergic neurons were detected using choline acetyltransferase immunohistochemistry in the putamen and pedunculopontine nucleus. Putaminal cholinergic neurons were quantified. A total of 6 cervical dystonia patients and 6 age-matched healthy controls underwent diffusion tensor imaging to determine if there were white matter microstructural abnormalities around the pedunculopontine nucleus. RESULTS: Decreased or absent choline acetyltransferase staining was identified in all 6 pedunculopontine nucleus samples in cervical dystonia. In contrast, strong choline acetyltransferase staining was present in 4 of 5 pedunculopontine nucleus controls. There were no differences in pedunculopontine nucleus diffusion tensor imaging between cervical dystonia and healthy controls. There was no difference in numbers of putaminal cholinergic neurons between cervical dystonia and controls. CONCLUSIONS: Our findings suggest that pedunculopontine nucleus choline acetyltransferase deficiency represents a functional cholinergic deficit in cervical dystonia. Structural lesions and confounding neurodegenerative processes were excluded by absence of neuronal loss, gliosis, diffusion tensor imaging abnormalities, and beta-amyloid, tau, and alpha-synuclein pathologies. © 2018 International Parkinson and Movement Disorder Society.

Cervical Spine Dysmorphism in Congenital Muscular Torticollis.

BACKGROUND: Congenital muscular torticollis is a common childhood musculoskeletal anomaly that might result in permanent craniofacial deformity, facial asymmetry, and changes in the cervical vertebrae, if not treated during early childhood. Although there have been many studies on cervical vertebral changes, their onset in children has not been previously studied. METHODS: Fifteen patients (aged <8 years) with a confirmed diagnosed of torticollis were included. Three-dimensional computed tomography scans were obtained, and segmentation of the cervical vertebrae was done. Division of the atlas and axis across the midsagittal plane was done to compare the anatomical changes. The volumes of each halves of the atlas and axis were measured. RESULTS: An apparent change was observed in the axis of the vertebral column when compared with that of the skull. There were progressive anatomical changes affecting the upper cervical vertebrae, which started to develop around the age of 8 months and became more evident in older children. The axis vertebra was the first to be affected. Rotational and bending deformities were the most likely changes to occur. Pearson correlation analysis showed a statistically significant trend in the volume and height changes for both halves of the atlas and axis (P < 0.001 and P < 0.001). CONCLUSIONS: Children with untreated congenital muscular torticollis show progressive anatomical changes of the cervical vertebrae which started at the age of 8 months. The severity of the deformity increased with the advance of age as well as with the severity of sternocleidomastoid tightness, which might result in permanent deformities.

Anatomy and cervical dystonia : "Dysfunction follows form".

At first glance, cervical dystonia might be an illustration of the well-known proposition "function follows form". Nevertheless, cervical dystonia is a highly non-physiological condition, which cannot be reproduced by healthy subjects and does not respond to the usual physiological rules. "Dysfunction follows form" might be the most accurate aphorism to define cervical dystonia. Taking into account this situation and recent insights, the anatomic approach needs to be adapted to allow a better understanding of semiology and to improve botulinum toxin therapy. In this review dealing with a new approach to cervical dystonia, we develop some practical anatomical concepts concerning the head and neck complex. Knowledge of cervical spine and muscular dysfunctions in cervical dystonia is an essential stage in treating cervical dystonia patients with botulinum toxin.

Dynamic cortical gray matter volume changes after botulinum toxin in cervical dystonia.

Previous electrophysiological and functional imaging studies in focal dystonia have reported on cerebral reorganization after botulinum toxin (BoNT) injections. With the exception of microstructural changes, alterations in gray matter volume after BoNT have not been explored. In this study, we sought to determine whether BoNT influences gray matter volume in a group of cervical dystonia (CD) patients. We analyzed whole brain gray matter volume in a sample of CD patients with VBM analysis. In patients, scans were repeated immediately before and some weeks after BoNT injections; controls were only scanned once. We analyzed 1) BoNT-related gray matter volume changes within patients; 2) gray matter volume differences between patients and controls; and 3) correlations between gray matter volume and disease duration and disease severity. The pre- and post-BoNT treatment analysis revealed an increase of gray matter volume within the right precentral sulcus, at the lateral border of the premotor cortex. In comparison to healthy controls, CD patients had reduced gray matter volume in area 45 functionally corresponding to the left ventral premotor cortex. No gray matter volume increase was found for CD patients in comparison to controls. Gray matter volume of the left supramarginal gyrus and left premotor cortex correlated positively with disease duration, and that of the right inferior parietal lobule correlated negatively with disease severity. We have identified structural, yet dynamic gray matter volume changes in CD. There were specific gray matter volume changes related to BoNT injections, illustrating indirect central consequences of modified peripheral sensory input. As differences were exclusively seen in higher order motor areas relevant to motor planning and spatial cognition, these observations support the hypothesis that deficits in these cognitive processes are crucial in the pathophysiology of CD.

Torticollis in children: an alert symptom not to be turned away.

PURPOSE: The aim of this study is to investigate the spectrum of underlying disease in children with torticollis. METHODS: We investigated the spectrum of underlying disease and to evaluate the clinical features of the children presented with torticollis in the last 2 years. RESULTS: Of the 20 children (13 girls and 7 boys with the mean age of 8 years, ranging 2 months-12 years), eight of them have craniospinal pathologies (cerebellar tumors in three, exophytic brain stem glioma, eosinophilic granuloma of C2 vertebra, neuroenteric cyst of the spinal cord, Chiari type 3 malformation, arachnoid cysts causing brainstem compression, and cerebellar empyema), followed by osseous origin in five (congenital vertebral anomalies including hemivertebrae, blocked vertebra, and segmentation anomalies), two muscular torticollis (soft tissue inflammation due to subclavian artery catheterization, myositis ossificans with sternocleidomastoid muscle atrophy), and ocular (congenital cataract and microphthalmia), Sandifer syndrome, paroxysmal torticollis, retropharyngeal abscess each in one patients were detected. Ten patients underwent surgery; two patients received medical therapy for reflux and benign paroxysmal torticollis; and one patient with torticollis due to muscle spasm and soft tissue inflammation was treated with physiotherapy. CONCLUSIONS: Various underlying disorders from relatively benign to life-threatening conditions may present with torticollis. The first step should be always a careful and complete physical examination, which must include all systems. Imaging must be performed for ruling out underlying life-threatening diseases in children with torticollis, particularly, if acquired neurological symptoms exist. Besides craniospinal tumors, ophthalmological problems and central nervous system infections should also be kept in mind. Moreover, early diagnosis of these disorders will reduce mortality and morbidity. Therefore, alertness of clinicians in pediatric and pediatric neurosurgery practice must be increased about this alert symptom.

[Pediatric intervertebral disc calcification: A rare cause of acquired torticollis. Case report]. / Discopatía calcificante de la infancia: una infrecuente causa de tortícolis adquirida. Caso clínico.

INTRODUCTION: Pain and cervical muscle spasm are common reasons why parents bring children to the pediatric emergency department. The first steps are the gathering of medical history of the patient and a physical examination. If musculoskeletal damage is suspected, cervical spine x-rays should be obtained. An intervertebral disc calcification finding, in the absence of other radiological lesions should suggest pediatric intervertebral disc calcification. OBJECTIVE: To present a case of intervertebral disc calcification, a rare condition that must be considered in the differential diagnosis of torticollis and neck pain in childhood. CASE REPORT: A seven-year-old male patient without morbid history and no history of trauma or rough sport practice. He consulted the emergency room for pain and cervical contracture for the last six days. C reactive protein and red cell sedimentatio rates were slightly elevated. Imaging studies showed calcification of the C5-C6 intrvertebral disc and anterior disc protrusion. The patient was hospitalized for evaluation and pain management, with good clinical response and continue afterwards with non-steroidal anti-inflammatory drugs and a soft collar. At the 6-month-follow up, the patient had resolved symptoms and calcifications. CONCLUSIONS: Pediatric intervertebral disc calcification is a rare cause of acquired torticollis, with a benign and self-limited outcome. Conservative management, as well as clinical and imaging follow-up is recommended.

Sensory tricks and brain excitability in cervical dystonia: a transcranial magnetic stimulation study.

BACKGROUND: Sensory tricks such as touching the face with fingertips often improve cervical dystonia [CD]. This study is to determine whether sensory tricks modulate motor cortex excitability, assessed by paired-pulse transcranial magnetic stimulation [p-pTMS]. METHODS: Eight patients with rotational CD underwent p-pTMS, at rest and when the sensory trick was applied. To test intracortical inhibition [ICI] and facilitation [ICF], the amplitude ratio between conditioned and unconditioned cortical motor evoked potentials was measured at several interstimulus intervals (ISI 1, 3, 15, and 20 ms) and compared with controls mimicking patients' sensory tricks. RESULTS: At rest, a significant ICF enhancement was found at ISIs 15 through 20 in patients compared with controls, whereas no significant ICI changes were observed. Sensory tricks significantly reduced the abnormal ICF in patients and did not induce any change in controls. CONCLUSIONS: In our CD patients, sensory tricks seem to improve dystonia through an inhibitory effect on motor cortex excitability.

Efficacy of microcurrent therapy in infants with congenital muscular torticollis involving the entire sternocleidomastoid muscle: a randomized placebo-controlled trial.

OBJECTIVE: To compare the effects of a combination of therapeutic exercise and ultrasound with or without additional microcurrent therapy in infants with congenital muscular torticollis involving the entire sternocleidomastoid muscle. DESIGN: Prospective, randomized, placebo-controlled trial. SETTING: An outpatient rehabilitation clinic in a tertiary university hospital. SUBJECTS: Infants (n = 20) with congenital muscular torticollis involving the entire sternocleidomastoid muscle. INTERVENTIONS: Group 1 comprised 10 infants who received therapeutic exercise with ultrasound alone and Group 2 comprised 10 infants who received the same treatment with microcurrent therapy. MAIN MEASURES: Passive cervical rotational range of motion was measured at before treatment and one, two, three, and six months after initial treatment. Thickness, cross-sectional area, and red pixel intensity on colour histograms, which were all assessed before treatment and at three months after initial treatment. Additionally, the duration of treatment was measured. RESULTS: The mean passive cervical rotational range of motion measured at three months posttreatment was significantly greater in Group 2 (101.1°) than that in Group 1 (86.4°), and the thickness, cross-sectional area, and red pixel intensity of the affected sternocleidomastoid muscle were all less in Group 2 (7.8 mm, 100.3 mm(2), and 126.1, respectively) than those in Group 1 (9.6 mm, 121.5 mm2, and 140.5, respectively). The mean duration of treatment was significantly shorter in Group 2 (2.6 months) than in Group 1 (6.3 months). CONCLUSIONS: Microcurrent therapy may increase the efficacy of therapeutic exercise with ultrasound for the treatment of congenital muscular torticollis involving the entire sternocleidomastoid muscle.

Different etiologies of acquired torticollis in childhood.

INTRODUCTION: Torticollis can be congenital or may be acquired in childhood. Acquired torticollis occurs because of another problem and usually presents in previously normal children. The causes of acquired torticollis include ligamentous, muscular, osseous, ocular, psychiatric, and neurologic disorders. OBJECTIVE: We performed this study to evaluate the underlying causes of torticollis in childhood. MATERIAL AND METHODS: Ten children presented with complaints of torticollis between April 2007 and April 2012 were enrolled in this study. The additional findings of physical examination included neck pain, twisted neck, walking disorder, imbalance, and vomiting The identified etiologies of the enrolled children was acute disseminated encephalomyelitis in a 2.5-year-old boy, posterior fossa tumor in a 10-month-old boy, spontaneous spinal epidural hematoma in a 5-year-old hemophiliac boy, cervical osteoblastoma in a 3-year-old boy, arachnoid cyst located at posterior fossa in a 16-month-old boy, aneurysm of the anterior communicating artery in a 6-year-old girl, pontine glioma in a 10-year-old girl, and a psychogenic torticollis in a 7-year-old boy were presented. CONCLUSION: There is a wide differential diagnosis for a patient with torticollis, not just neurological in etiology which should be considered in any patient with acquired torticollis. Moreover, early diagnosis of etiological disease will reduce mortality and morbidity. Therefore, clinicians managing children with torticollis must be vigilant about underlying neurological complications.

The nerve of McKenzie: anatomic study with application to intradural rhizotomy for spasmodic torticollis.

INTRODUCTION: Medically recalcitrant spasmodic torticollis may necessitate surgical intervention. One procedure used for this pathologic entity is intradural rhizotomy. However, some patients are symptomatic, perhaps due to an overlooked or underappreciated nerve of McKenzie. The authors' goal was to further elucidate the anatomy of this nerve of the craniocervical junction. MATERIALS AND METHODS: Fifteen adult cadavers (30 sides) underwent microsurgical dissection and observations of the nerve of McKenzie. Morphometrics were performed and anatomic relationships were documented under surgical magnification. RESULTS: The nerve of McKenzie was found on 70% of sides and was always a single branch. Average length was 5.2 mm for left sides and 6 mm for right sides. Average diameter was 0.9 mm (0.5-1.2 mm). In two specimens, the nerve was found bilaterally. It pierced the first denticulate ligament on 11 sides (52.4%) and travelled through its two prongs on three sides (14.3%) to connect to the anteriorly placed C1 ventral root. On five sides, it was in intimate contact with the adventitia of the vertebral artery. It was more common on right sides and in males, and this was statistically significant. CONCLUSIONS: The authors identified the nerve of McKenzie in most specimens. This nerve, if overlooked during surgical treatment of spasmodic torticollis, may result in continued symptoms. The nerve of McKenzie was often concealed within the denticulate ligament or adventitia of the vertebral artery. The authors hope the data presented here will aid neurosurgeons and decrease complications in patients who undergo neurotomy for spasmodic torticollis.

Superior colliculus mediates cervical dystonia evoked by inhibition of the substantia nigra pars reticulata.

Cervical dystonia (CD; spasmodic torticollis) can be evoked by inhibition of substantia nigra pars reticulata (SNpr) in the nonhuman primate (Burbaud et al., 1998; Dybdal et al., 2012). Suppression of GABAergic neurons that project from SNpr results in the disinhibition of the targets to which these neurons project. It therefore should be possible to prevent CD by inhibition of the appropriate nigral target region(s). Here we tested the hypothesis that the deep and intermediate layers of the superior colliculus (DLSC), a key target of nigral projections, are required for the emergence of CD. To test this hypothesis, we pretreated the DLSC of four macaques with the GABA(A) agonist muscimol to determine whether this treatment would prevent CD evoked by muscimol infusions in SNpr. Our data supported this hypothesis: inhibition of DLSC attenuated CD evoked by muscimol in SNpr in all four animals. In two of the four subjects, quadrupedal rotations were evoked by muscimol application into SNpr sites that were distinct from those that induced dystonia. We found that inhibition of DLSC did not significantly alter quadrupedal rotations, suggesting that this response is dissociable from the SNpr-evoked CD. Our results are the first to demonstrate a role of DLSC in mediating the expression of CD. Furthermore, these data reveal a functional relationship between SNpr and DLSC in regulating posture and movement in the nonhuman primate, raising the possibility that the nigrotectal pathway has potential as a target for therapeutic interventions for CD.

Structural brain abnormalities in cervical dystonia.

BACKGROUND: Idiopathic cervical dystonia is characterized by involuntary spasms, tremors or jerks. It is not restricted to a disturbance in the basal ganglia system because non-conventional voxel-based MRI morphometry (VBM) and diffusion tensor imaging (DTI) have detected numerous regional changes in the brains of patients.In this study scans of 24 patients with cervical dystonia and 24 age-and sex-matched controls were analysed using VBM, DTI and magnetization transfer imaging (MTI) using a voxel-based approach and a region-of-interest analysis. Results were correlated with UDRS, TWSTRS and disease duration. RESULTS: We found structural alterations in the basal ganglia; thalamus; motor cortex; premotor cortex; frontal, temporal and parietal cortices; visual system; cerebellum and brainstem of the patients with dystonia. CONCLUSIONS: Cervical dystonia is a multisystem disease involving several networks such as the motor, sensory and visual systems.