OBJECTIVE:Essential tremor (ET) is common and disabling in older adults. Many patients aged ≥ 80 years are ineligible for deep brain stimulation due to medical comorbidities. Data on noninvasive alternatives, such as MR-guided high-intensity focused ultrasound (MRgHIFU), remain limited in this population. The aim of this study was to evaluate the safety and efficacy of unilateral MRgHIFU thalamotomy targeting the ventral intermediate nucleus (VIM) for the treatment of ET in patients ≥ 80 years of age. METHODS:This retrospective multicenter cohort study included consecutive patients aged ≥ 80 years with medically refractory ET treated with unilateral MRgHIFU VIM thalamotomy between 2016 and 2023 at five academic neurosurgical centers. All patients met skull density ratio criteria and underwent standardized targeting. Clinical assessments were conducted at baseline, immediately posttreatment, and at the 3-month follow-up. The primary outcome was change in tremor severity assessed by using the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS). Secondary outcomes included the Clinical Rating Scale for Tremor (CRST) score, Dynamic Gait Index score, patient-reported tremor relief, and adverse events. RESULTS:One hundred twenty-nine patients (76 male, mean age 84 years) were included. At 3 months, the mean TETRAS score improved by 9.2 points (p < 0.001). CRST scores also showed significant improvement. The mean patient-reported tremor relief was 81%. Adverse events were mild and transient, with a 1.6% rate of nonsurgical adverse events. Subgroup analysis comparing patients 80-84 years versus those ≥ 85 years of age showed no significant differences in treatment response. Gait outcomes improved modestly but were not significant in the age ≥ 85 years group. CONCLUSIONS:Unilateral MRgHIFU thalamotomy is a safe and effective noninvasive treatment for ET in patients ≥ 80 years of age. It results in significant improvements in tremor and disability, with a low complication rate. These findings support its consideration for older patients who are ineligible for invasive procedures and highlight the importance of age-specific metrics in neuromodulation outcomes research.

Functional pituitary adenomas often require multimodal therapy when surgery and medical treatment do not achieve durable endocrine remission. Stereotactic radiosurgery (SRS) is commonly used for residual or recurrent hormone-secreting tumors, achieving high tumor control rates but variable rates of biochemical remission. To evaluate endocrine response, tumor control, and treatment-related toxicity after linear accelerator (LINAC)-based SRS for functional pituitary adenomas. We retrospectively reviewed 24 patients treated with single-fraction LINAC SRS between 1995 and 2012 for adrenocorticotropic hormone (ACTH)-secreting (n = 6), growth hormone (GH)-secreting (n = 10), or prolactin (PRL)-secreting (n = 8) pituitary adenomas. All patients had prior transsphenoidal resection; most had failed or intolerant medical therapy. Two patients underwent repeat SRS for persistent disease, yielding 26 total SRS sessions. Endocrine outcomes were categorized as complete biochemical remission off medication, biochemical control while still requiring suppressive medical therapy, partial biochemical improvement without normalization, or persistent hypersecretion. Radiographic tumor control and late complications were assessed on long-term follow-up. After initial SRS, complete biochemical remission off medication was achieved in 3 of 6 patients with ACTH-secreting adenomas (50

OBJECTIVES:This study aimed to describe clinical outcomes, dosing, and safety of intrathecal baclofen (ITB) therapy in patients with medically refractory stiff person syndrome (SPS). MATERIALS AND METHODS:We retrospectively reviewed six patients with predominantly anti-glutamic acid decarboxylase (GAD)-positive SPS who underwent ITB pump implantation after inadequate response or intolerance to oral antispasticity medications and immunomodulatory therapies. Clinical features, prior treatments, ITB dosing, complications, and functional outcomes were analyzed. RESULTS:All the patients had severe stiffness and stimulus-sensitive spasms refractory to benzodiazepines, oral baclofen, and immunotherapy. Indications for ITB included respiratory compromise (n = 2), recurrent hip dislocations (n = 2), severe functional impairment (n = 6), and medication intolerance (n = 3). Maintenance ITB doses ranged from 365 to 650 μg/d. All patients experienced substantial reductions in stiffness and spasm frequency, with improved mobility or respiratory function. In one patient, postoperative septic shock developed, requiring temporary device removal; no long-term device failures occurred. Clinical benefit was sustained for 2.5 to four years of follow-up. DISCUSSION:ITB therapy may provide durable symptomatic improvement in severe, medically refractory SPS and should be considered in appropriately selected patients.

Aromatic ʟ-amino acid decarboxylase (AADC) deficiency is a rare pediatric neurotransmitter disorder that typically necessitates lifelong care, and that carries a risk of childhood mortality. Eladocagene exuparvovec gene therapy is designed to restore AADC production. Study GT-002 (NCT04903288) is a phase 2, multicenter, open-label trial assessing the pharmacodynamics, safety, and efficacy of eladocagene exuparvovec administered to the putamen bilaterally in pediatric patients with AADC deficiency using a magnetic resonance (MR)-compatible cannula. Patients received eladocagene exuparvovec at 1.8 × 1011 vector genomes via the SmartFlow MR-compatible cannula in a single operative session. Endpoints include the change from baseline in cerebrospinal fluid homovanillic acid levels, motor milestone achievement, and safety. Here we report results from 48 weeks of follow-up. Mean (SD) cerebrospinal fluid homovanillic acid levels increased from baseline (22.5 [32.3] nmol/L; n = 13) to week 48 (55.3 [45.6] nmol/L; change from baseline: 28.3 [13.7] nmol/L; p = 0.0003; n = 9), indicating de novo dopamine production. At baseline (n = 13), all patients showed severe motor developmental delay; at week 48 (n = 12), nine achieved full head control, four could sit unassisted, two could stand with support, and two could walk independently to a toy. Overall, 260 treatment-emergent adverse events were reported in 13 patients; 259 were deemed unrelated and one likely unrelated to the MR-compatible cannula. No treatment-emergent adverse events led to study withdrawal and no deaths occurred. This study provides further evidence of the favorable pharmacodynamic, efficacy, and safety profile of eladocagene exuparvovec in children with AADC deficiency; intraputaminal administration using an MR-compatible cannula was well tolerated. Study GT-002 (NCT04903288) provides further evidence of the favourable pharmacodynamic, efficacy and safety profile of eladocagene exuparvovec gene therapy in children with AADC deficiency over 48 weeks and demonstrates that intraputaminal administration using an MR-compatible cannula was well tolerated, allowing for real-time MRI confirmation of cannula placement and infusate coverage, and for accurate dosing to the putamen.

BACKGROUND:Nonmissile craniofacial penetrating injuries from elongated metallic objects are uncommon and carry significant risks related to concealed vascular injury, hemorrhage, dural violation, and infection. Early CT and selective vascular imaging guide safe management, and blind extraction outside the operating room (OR) should be avoided. OBSERVATIONS:A 17‑year‑old male presented after transfacial penetration by a "supergun" rod entering inferior to the right zygomatic arch and tracking beneath the temporal squama toward the middle cranial fossa. He arrived with a Glasgow Coma Scale score of 15, an intact airway, and no focal deficits. CT/CT angiograpy (CTA) showed intracranial extension without major vascular injury. In the OR, a right parietotemporal trauma flap incision enabled a targeted temporal craniotomy; the protruding rod was shortened intraoperatively to reduce lever forces and then extracted along the entry trajectory under direct vision with hemostasis. Postoperative CT imaging revealed a right parietotemporal epidural hematoma adjacent to the craniotomy, which was promptly evacuated. Recovery was otherwise uneventful under a 3‑week antibiotic course and 1‑month levetiracetam prophylaxis. Follow‑up CT imaging at approximately 3 weeks showed resolution and satisfactory healing. LESSONS:For elongated metallic skull penetrating injuries, CTA‑guided planning, avoidance of blind extraction, and controlled OR removal augmented by intraoperative shortening when needed are key to minimizing hemorrhage and neurological injury. https://thejns.org/doi/10.3171/CASE25670.

Cognitive outcome following mild traumatic brain injury (mTBI) vary widely, with many individuals experiencing long-term impairments associated with frontoparietal network dysfunction. Mild TBI patients have demonstrated functional reorganization, suggesting an expansion of activation to cerebellar regions during specific executive functions. In this study, we investigated cerebellar involvement in fluid intelligence processing using a novel fMRI paradigm based on Raven's Progressive Matrices in 51 acute mTBI patients and 61 healthy controls. Despite comparable task accuracy, mTBI patients exhibited significantly increased activation in anterior cerebellar regions, including Vermis III and Cerebellum IV-V. Seed-based functional connectivity analysis further revealed altered cerebellar-frontoparietal interactions in mTBI patients compared to healthy controls. In mTBI patients, connectivity was enhanced with the left lateral prefrontal cortex and lower with the right posterior parietal cortex, which also showed a change from positive to negative connectivity. These findings suggest that the cerebellum is adaptively recruited to maintain cognitive performance, in line with the cerebellar reserve theory. This study provides initial evidence of cerebellar activation during fluid intelligence processing in mTBI, highlighting a potential role for the cerebellum in adaptively interacting with cortical networks to support cognitive function following brain injury.

The amygdala and hippocampus are central to emotional processing, yet the transient neural dynamics coordinating these regions remain unclear. We simultaneously recorded single-neuron activity and local field potentials from both regions in epilepsy patients during an emotional image-rating task. Neurons in both regions responded to images with firing rate changes that predicted subjective ratings of extreme pleasantness or unpleasantness. To examine the underlying oscillatory mechanisms, we analyzed beta bursts (13-30 Hz)-transient, high-power events-since conventional spectral analyses revealed no valence-specific patterns. Beta bursts were associated with increased gamma amplitude and enhanced phase coherence in both structures, with beta-gamma phase-amplitude coupling capturing emotion-related dynamics. Critically, amygdala beta bursts strongly suppressed hippocampal firing through interneuron activation during negative valence processing, whereas hippocampal bursts showed no reciprocal influence. These findings suggest that beta bursts provide a temporal code for emotion and represent a candidate mechanism for targeted neuromodulation in mood disorders.

Nitrous oxide is a common gaseous anesthetic used in a wide range of medical procedures due to its desirable combination of anesthetic and analgesic properties. Deep brain stimulation surgery, a well-established treatment for movement disorders like Parkinson's disease, often requires precise microelectrode recordings of the awake brain's electrical signals for optimal results. However, the influence of anesthetics on these brain signals remains a critical consideration. This study investigated how nitrous oxide general anesthesia supplemented by ketamine affects the electrophysiology of the subthalamic nucleus compared to awake and low-dose ketamine sedation during deep brain stimulation procedures targeting the subthalamic nucleus of Parkinson's disease patients. Spectral analysis of subthalamic nucleus electrophysiological characteristics and statistical analysis of its electrophysiological dimensions were performed on retrospective data from three medical centers. Our findings revealed that nitrous-ketamine general anesthesia allows electrophysiological subthalamic nucleus identification, despite a slight decrease in overall activity level. Nevertheless, nitrous-ketamine showed significantly lower beta frequency power inside the nucleus compared to the ketamine and awake groups. At the group level, and in many trajectories, delineation of subthalamic nucleus subdomains can be achieved by detection of changes in the delta frequency oscillations. Notably, no differences in electrophysiological nucleus dimensions were found between the three groups. These findings suggest that it is possible to recognize the entrance and exit of the subthalamic nucleus with high confidence under nitrous oxide-ketamine anesthesia. However, the motor subregion of the nucleus is more difficult to delineate under nitrous anesthesia than ketamine sedation or awake, which may affect outcome.

Statistical learning, the fundamental cognitive ability of humans to extract regularities across experiences over time, engages the medial temporal lobe in the healthy brain. This leads to the hypothesis that statistical learning may be impaired in epilepsy patients, and that this impairment could contribute to their varied memory deficits. In turn, epilepsy patients provide a platform to advance basic understanding of statistical learning by helping to evaluate the necessity of medial temporal lobe circuitry through disease and causal perturbations. We implemented behavioral testing, volumetric analysis of the medial temporal lobe substructures, and direct electrical brain stimulation to examine statistical learning across a cohort of 61 epilepsy patients and 28 healthy controls. Behavioral performance in a statistical learning task was negatively associated with seizure frequency, irrespective of where seizures originated in the brain. The volume of hippocampal subfields CA1 and CA2/3 correlated with statistical learning performance, suggesting a more specific role of the hippocampus. Indeed, transient direct electrical stimulation of the hippocampus disrupted statistical learning. Furthermore, the relationship between statistical learning and seizure frequency was selective: behavioral performance in an episodic memory task was impacted by structural lesions in the medial temporal lobe and by antiseizure medications, but not by seizure frequency. Overall, these results suggest that statistical learning may be hippocampally dependent and that this task could serve as a clinically useful behavioral assay of seizure frequency distinct from existing neuropsychological tests. Simple and short statistical learning tasks may thus provide patient-centered endpoints for evaluating the efficacy of novel treatments in epilepsy.

BACKGROUND:There remains high variability in clinical outcomes when the same magnetic resonance image-guided focused ultrasound (MRgFUS) thalamotomy target is used for both essential tremor (ET) and tremor-dominant Parkinson's disease (TDPD). OBJECTIVE:Our goal is to refine the MRgFUS thalamotomy target for TDPD versus ET. METHODS:We retrospectively performed voxel-wise efficacy and structural connectivity mapping using 3-12-month post-procedure hand tremor scores for a multicenter cohort of 32 TDPD patients and a previously published cohort of 79 ET patients, and 24-hour T1-weighted post-MRgFUS brain images. We validated our findings using Unified Parkinson's Disease Rating Scale part III scores for an independent cohort of nine TDPD patients. RESULTS:The post-MRgFUS clinical improvements were 45.9% ± 35.9%, 55.5% ± 36%, and 46.1% ± 18.6% for ET, multicenter TDPD and validation TDPD cohorts, respectively. The TDPD and ET efficacy maps differed significantly (ppermute < 0.05), with peak TDPD improvement (87%) at x = -13.5; y = -15.0; z = 1.5, ~3.5 mm anterior and 3 mm dorsal to the ET target. Discriminative connectivity projections were to the motor and premotor regions in TDPD, and to the motor and somatosensory regions in ET. The disorder-specific voxel-wise efficacy map could be used to estimate outcome in TDPD patients with high accuracy (R = 0.8; R2 = 0.64; P < 0.0001). The model was validated using the independent cohort of nine TDPD patients (R = 0.73; R2 = 0.53; P = 0.025-voxel analysis). CONCLUSION:We demonstrated that the most effective MRgFUS thalamotomy target in TDPD is in the ventral intermediate nucleus/ventralis oralis posterior border region. This finding offers new insights into the thalamic regions instrumental in tremor control, with pivotal implications for improving treatment outcomes. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Occipital lobe epilepsy is a debilitating condition, and surgical resection has been effective, though challenges arise because of the cortex's function.(1-7)Approximately 57% of patients with normal vision experience new visual field deficitspostoperatively.8A combined approach of resection and responsive neurostimulation (RNS) could aid in decreasing thevisual field area severed and the disability tied to it while obtaining seizure freedom.(9,10)We aimed to present a case of medically refractory occipital lobe epilepsy with involvement of the primary visual cortex treated with a combined approach. The patient consented to the procedure and to the publication of his image. Any identifiable individuals consented to publication of his/her image. A 21-year-old right-handed male experienced refractory epilepsy since age 1 year. His first seizure was a severe refractorystatus epilepticus which resulted in cardiac arrest. His usual seizure semiology exhibited focal impaired awareness tobilateral tonic-clonic seizures occurring monthly. Noninvasive tests did not provide precise localization, but the intracranial electroence phalogram confirmed seizure onset in the right cuneus with rapid spread to the lingual gyrus and the superiorparietal lobe. We performed a corticectomy(11)of the seizure onset zone and used RNS to address spreading areas in the parietal and occipital lobe. A complete lobectomy was avoided to prevent postoperative homonymous hemianopsia in a previously intact patient. The patient was discharged on postoperative day 3 with a nondisabling left inferior quad-rantanopia. No clinical seizures were detected after RNS was turned on, rendering so far 8.5 months of seizure freedom. The combined surgical approach appears promising for medically refractory epilepsy involving functional areas

BACKGROUND AND OBJECTIVES:As advancements in cancer treatments have allowed patients with a high burden of disease to live longer, the number of patients who present with debilitating refractory pain has increased. Anterolateral cordotomy has long been used for the treatment of intractable unilateral cancer pain using either an imaging-guided percutaneous approach or an open surgical approach. In this report, we describe a novel minimally invasive modification to the open surgical approach. It combines the benefits of both approaches by providing direct visualization for lesioning without the collateral tissue damage of an open approach. METHODS:This retrospective study evaluated medical records, operative reports, and imaging studies of patients who underwent a minimally invasive cordotomy at a single institute between 2018 and 2022. The surgical technique involved a microscope-assisted C2 hemilaminectomy using microtubular retractors followed by dural opening and anterolateral cordotomy under direct visualization and with intraoperative neurophysiological monitoring. RESULTS:Eleven patients were included in the study. None were converted to an open approach, and no wound-related postoperative complications were observed. A clinically significant decrease in pain was observed after the procedure, and 10 of the 11 patients (91%) were ambulatory by the time of analysis. CONCLUSION:Compared with image-guided percutaneous cordotomy, anterolateral cervical cordotomy with microtubular retractors potentially improves the safety of the procedure through direct visualization while being less invasive than a conventional open approach. Our preliminary experience with this technique demonstrates the feasibility of the approach, as it was both safe and effective.

OBJECTIVE:MRI-guided low-intensity focused ultrasound (FUS) has been shown to reversibly open the blood-brain barrier (BBB), with the potential to deliver therapeutic agents noninvasively to target brain regions in patients with Alzheimer's disease (AD) and other neurodegenerative conditions. Previously, the authors reported the short-term safety and feasibility of FUS BBB opening of the hippocampus and entorhinal cortex (EC) in patients with AD. Given the need to treat larger brain regions beyond the hippocampus and EC, brain volumes and locations treated with FUS have now expanded. To evaluate any potential adverse consequences of BBB opening on disease progression, the authors report safety, imaging, and clinical outcomes among participants with mild AD at 6-12 months after FUS treatment targeted to the hippocampus, frontal lobe, and parietal lobe.METHODS:In this open-label trial, participants with mild AD underwent MRI-guided FUS sonication to open the BBB in β-amyloid positive regions of the hippocampus, EC, frontal lobe, and parietal lobe. Participants underwent 3 separate FUS treatment sessions performed 2 weeks apart. Outcome assessments included safety, imaging, neurological, cognitive, and florbetaben β-amyloid PET.RESULTS:Ten participants (range 55-76 years old) completed 30 separate FUS treatments at 2 participating institutions, with 6-12 months of follow-up. All participants had immediate BBB opening after FUS and BBB closure within 24-48 hours. All FUS treatments were well tolerated, with no serious adverse events related to the procedure. All 10 participants had a minimum of 6 months of follow-up, and 7 participants had a follow-up out to 1 year. Changes in the Alzheimer's Disease Assessment Scale-cognitive and Mini-Mental State Examination scores were comparable to those in controls from the Alzheimer's Disease Neuroimaging Initiative. PET scans demonstrated an average β-amyloid plaque of 14% in the Centiloid scale in the FUS-treated regions.CONCLUSIONS:This study is the largest cohort of participants with mild AD who received FUS treatment, and has the longest follow-up to date. Safety was demonstrated in conjunction with reversible and repeated BBB opening in multiple cortical and deep brain locations, with a concomitant reduction of β-amyloid. There was no apparent cognitive worsening beyond expectations up to 1 year after FUS treatment, suggesting that the BBB opening treatment in multiple brain regions did not adversely influence AD progression. Further studies are needed to determine the clinical significance of these findings. FUS offers a unique opportunity to decrease amyloid plaque burden as well as the potential to deliver targeted therapeutics to multiple brain regions in patients with neurodegenerative disorders.

Surgical targeting of the ventral intermediate nucleus of the thalamus (VIM) has been historically done using indirect strategies. Here we depict the cerebello-thalamo-cortical tract (CTCT) through 3 T proton density (PD) in a cohort of patients who underwent high-intensity focus ultrasound (HIFUS) thalamotomy. Forty-seven patients treated in our institution with MR-guided HIFUS VIM thalamotomy were included in this study. PD weighted 3 T MRI used for presurgical planning was compared with postoperative MRI obtained 1 month after surgery. Images were processed with ISTX software (Brain lab, Munich, Germany). The coordinates of the VIM lesion concerning the inter-commissural line (ICL) were annotated. Deterministic tractographies using three ROIs were used to verify the different tracts. The triangle seen in the 3 T PD sequence at the level of the mesencephalic-diencephalic junction was systematically recognized. The posterior angle of this triangle at the junction of the CTCT and the ZI was denominated as “point P.” The area of this triangle corresponds to the posterior subthalamic area (PSA) harboring the Raprl fibers. The CTCT was visible from 1 to 2.5 mm below the ICL. The average center of the final HIFUS lesion (point F) was 11 mm from the medial thalamic border of the thalamus (14.9 mm from the midline), 6.4 mm anterior to PC, and 0.6 mm above the ICL. The FUS point was consistently 1–2 mm directly above point P. The anterior border of the external angle of this triangle (point P) can be used as an intraparenchymal point for targeting the ventral border of the VIM. Three ROIs placed in a single slice around this triangle are a fast way to originate tractography of the CTCT, lemniscus medialis, and pyramidal tract.

Ultrasound in combination with the introduction of microbubbles into the vasculature effectively opens the blood brain barrier (BBB) to allow the passage of therapeutic agents. Increased permeability of the BBB is typically demonstrated with small-molecule agents (e.g., 1-nm gadolinium salts). Permeability to small-molecule agents, however, cannot reliably predict the transfer of remarkably larger molecules (e.g., monoclonal antibodies) required by numerous therapies. To overcome this issue, we developed a magnetic resonance imaging analysis based on the ΔR 2 * physical parameter that can be measured intraoperatively for efficient real-time treatment management. We demonstrate successful correlations between ΔR 2 * values and parenchymal concentrations of 3 differently sized (18 nm–44 nm) populations of liposomes in a rat model. Reaching an appropriate ΔR 2 * value during treatment can reflect the effective delivery of large therapeutic agents. This prediction power enables the achievement of desirable parenchymal drug concentrations, which is paramount to obtaining effective therapeutic outcomes.

BACKGROUND: A definitive diagnosis of brain lesions not amenable to surgery is mainly made by stereotactic needle biopsy. The diagnostic yield and safety of the frameless versus frame-based image-guided stereotactic techniques is unclear. Our objective was to evaluate the safety and accuracy of frameless versus frame-based stereotactic brain biopsy techniques. METHODS: A total of 278 patients (153 men; mean age: 65.5 years) with intra-axial brain lesions underwent frame-based (n = 148) or frameless image-guided stereotactic brain biopsy (n = 130) using a minimally invasive twist drill technique during 2010-2016 at Sheba Medical Center. Demographic, imaging, and clinical data were retrospectively analyzed. RESULTS: The diagnostic yield (>90%) did not differ significantly between groups. Overall morbidity (6.8% vs. 8.5%), incidence of permanent neurologic deficits (2.1% vs. 1.6%), mortality rate (0.7% vs. 0.8%), and postoperative computed tomography-detected asymptomatic (14.2% vs. 16.1%) and symptomatic (2.0% vs. 1.6%) bleeding also did not differ significantly between the frame-based and frameless cohorts, respectively. The diagnostic yield and complication rates related to the biopsy technique were not significantly associated with sex, age, entry angle to the skull and skull thickness, lesion location or depth, or radiologic characteristics. Diagnostic yield was significantly associated with the mean lesion volume. Smaller lesions were less diagnostic than larger lesions in both techniques (P = 0.043 frame-based and P = 0.048 frameless). CONCLUSIONS: The frameless biopsy technique is as efficient as the frame-based brain biopsy technique with a low complication rate. Lesion volume was the only predictive factor of diagnostic yield. The minimally invasive twist drill technique is safe and efficient.

Recent reports indicate that Parkinson's disease (PD) involves specific functional abnormalities in residual neurons - decreased vesicular sequestration of cytoplasmic catecholamines via the vesicular monoamine transporter (VMAT) and decreased aldehyde dehydrogenase (ALDH) activity. This double hit builds up the autotoxic metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), the focus of the catecholaldehyde hypothesis for the pathogenesis of PD. An animal model is needed that reproduces this abnormal catecholamine neurochemical pattern. Adult rats received subcutaneous vehicle or the mitochondrial complex 1 inhibitor rotenone (2 mg/kg/day via a minipump) for 10 days. Locomotor activity was recorded, and striatal tissue sampled for catechol contents and catechol ratios that indicate the above abnormalities. Compared to vehicle, rotenone reduced locomotor activity (P=0.002), decreased tissue dopamine concentrations (P=0.00001), reduced indices of vesicular sequestration (3,4-dihydroxyphenylacetic acid (DOPAC)/dopamine) and ALDH activity (DOPAC/DOPAL) (P=0.0025, P=0.036), and increased DOPAL levels (P=0.04). The rat rotenone model involves functional abnormalities in catecholaminergic neurons that replicate the pattern found in PD putamen. These include a vesicular storage defect, decreased ALDH activity and DOPAL build-up. The rat rotenone model provides a suitable in vivo platform for studying the catecholaldehyde hypothesis.

Background. To determine the utility of an intraoperative magnetic resonance imaging (iMRI) system, the Polestar N30, for enhancing the resection control of non-enhancing intra-axial brain lesions. Materials and methods. Seventy-three patients (60 males [83.3%], mean age 37 years) with intra-axial brain lesions underwent resection at Sheba Medical Centre using the Polestar between February 2012 and the end of August 2018. Demographic and imaging data were retrospectively analysed. Thirty-five patients had a non-enhancing lesion (48%). Results. Complete resection was planned for 60/73 cases after preoperative imaging. Complete resection was achieved in 59/60 (98.3%) cases. After iMRI, additional resection was performed in 24/73 (32.8%) cases, and complete resection was performed in 17/60 (28.8%) cases in which a complete resection was intended. In 6/13 (46%) patients for whom incomplete resection was intended, further resection was performed. The extent of resection was extended mainly for non-enhancing lesions: 16/35 (46%) as opposed to only 8/38 (21%) for enhancing lesions. Further resection was not significantly associated with sex, age, intended resection, recurrence, or affected side. Univariate analysis revealed non-eloquent area, intended complete resection, and enhancing lesions to be predictive factors for complete resection, and non-enhancing lesions and scan time to be predictive factors for an extended resection. Non-enhancement was the only independent factor for extended resection. Conclusions. The Polestar N30 is useful for evaluating residual non-enhancing intra-axial brain lesions and achieving maximal resection.