Lesions in the pedunculopontine nucleus (PPN) cause akinesia. The PPN degenerates in Parkinson's disease. Stimulation of the PPN region induces stepping movements in rats and cats. These findings suggest that the PPN may play an important role in akines ia and that stimulating it may alleviate akinesia.Therefore, we have stereotactically implanted a macroelectrode in the left PPN region in a normal macaque to investigate the effects of deep brain stimulation at different frequencies. Motor activity was recorded with an infra-red counter and behaviour videotaped. At frequencies above 45 Hz there was significantly more severe akinesia than at lower frequencies (paired t -test, n=15, P<0.005). At 100 Hz, there was gross impairment of postural control. At low frequencies (5-30 Hz), stimulation induced a 5-Hz tremor in the right arm. We conclude that stimulating the PPN region at high frequency causes akinesia, whereas low frequencies induce some positive motor effects.
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http://dx.doi.org/10.1054/jocn.2001.0943 | DOI Listing |
Geroscience
January 2025
Department of Neurology, Ewha Womans University Mokdong Hospital, Ewha Womans University College of Medicine, Seoul, Republic of Korea.
Background: Superagers, older adults with exceptional cognitive abilities, show preserved brain structure compared to typical older adults. We investigated whether superagers have biologically younger brains based on their structural integrity.
Methods: A cohort of 153 older adults (aged 61-93) was recruited, with 63 classified as superagers based on superior episodic memory and 90 as typical older adults, of whom 64 were followed up after two years.
Acta Neurochir (Wien)
January 2025
Department of Neurosurgery and Department of Neuroscience, Fujian Key Laboratory of Brain Tumors Diagnosis and Precision Treatment, Xiamen Key Laboratory of Brain Center, the First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
Purpose: To investigate the technique for dorsal median sulcus (DMS) mapping and assess its application value in preserving dorsal columnn (DC) function during intramedullary space occupying surgery based on a single-center experience.
Methods: A retrospective analysis was conducted on 41 cases of intramedullary spinal cord tumor admitted to the Department of Neurosurgery at the First Affiliated Hospital of Xiamen University from March 2017 to August 2023. All included cases underwent intraoperative electrophysiological monitoring, and were divided into a study group (n = 18) and a control group (n = 23), based on whether DMS mapping technique was utilized.
Stereotact Funct Neurosurg
January 2025
Introduction: In 2015, directional leads have been released in Europe for deep brain stimulation (DBS) and have been particularly used for subthalamic nucleus (STN) DBS for Parkinson's disease (PD). In this study we aimed to compare an omnidirectional and directional leads cohort of PD patients when it comes to clinical effectiveness and to assess the correlation with volume of tissue activated - target overlap (VTA-target).
Methods: A total of 60 consecutive patients were retrospectively included.
Nat Methods
January 2025
Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Teravoxel-scale, cellular-resolution images of cleared rodent brains acquired with light-sheet fluorescence microscopy have transformed the way we study the brain. Realizing the potential of this technology requires computational pipelines that generalize across experimental protocols and map neuronal activity at the laminar and subpopulation-specific levels, beyond atlas-defined regions. Here, we present artficial intelligence-based cartography of ensembles (ACE), an end-to-end pipeline that employs three-dimensional deep learning segmentation models and advanced cluster-wise statistical algorithms, to enable unbiased mapping of local neuronal activity and connectivity.
View Article and Find Full Text PDFParkinsonism Relat Disord
January 2025
University of Colorado Anschutz Medical Campus, Department of Neurosurgery, USA.
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