Search results for "POSITRON-EMISSION-TOMOGRAPHY"
showing 5 items of 5 documents
Direction-dependent activation of the insular cortex during vertical and horizontal hand movements
2016
International audience; The planning of any motor action requires a complex multisensory processing by the brain. Gravity - immutable on Earth - has been shown to be a key input to these mechanisms. Seminal fMRI studies performed during visual perception of falling objects and self-motion demonstrated that humans represent the action of gravity in parts of the cortical vestibular system; in particular, the insular cortex and the cerebellum. However, little is known as to whether a specific neural network is engaged when processing non-visual signals relevant to gravity. We asked participants to perform vertical and horizontal hand movements without visual control, while lying in a 3T-MRI sc…
Frontoparietal cortex and cerebellum contribution to the update of actual and mental motor performance during the day
2016
AbstractActual and imagined movement speed increases from early morning until mid-afternoon. Here, we investigated the neural correlates of these daily changes. Fifteen subjects performed actual and imagined right finger opposition movement sequences at 8 am and 2 pm. Both actual and imagined movements were significantly faster at 2 pm than 8 am. In the morning, actual movements significantly activated the left primary somatosensory and motor areas, and bilaterally the cerebellum; in the afternoon activations were similar but reduced. Contrast analysis revealed greater activity in the cerebellum, the left primary sensorimotor cortex and parietal lobe in the morning than in the afternoon. Im…
Synthesis and Characterization of a Novel Series of Agonist Compounds as Potential Radiopharmaceuticals for Imaging Dopamine D-2/3 Receptors in Their…
2014
Imaging of dopamine D2/3 receptors (D2/3R) can shed light on the nature of several neuropsychiatric disorders in which dysregulation of D2/3R signaling is involved. Agonist D2/3 tracers for PET/SPECT imaging are considered to be superior to antagonists because they are more sensitive to dopamine concentrations and may selectively label the high-affinity receptor state. Carbon-11-labeled D2/3R agonists have been developed, but these short-lived tracers can be used only in centers with a cyclotron. Here, we report the development of a series of novel D2R agonist compounds based on the 2-aminomethylchromane (AMC) scaffold that provides ample opportunities for the introduction of longer-lived […
Synthesis and evaluation in rats of the dopamine D2/3 receptor agonist 18F-AMC20 as a potential radioligand for PET
2015
Dopamine D2/3 receptor (D2/3R) agonist PET tracers are better suited for the imaging of synaptic dopaminergic neurotransmission than D2/3R antagonists and may also offer the opportunity to study in vivo the high-affinity state of D2/3R (D2/3RHigh). With the aim to develop 18F-labeled D2/3R agonists suitable for widespread clinical application, we report here on the synthesis and in vitro and in vivo evaluation of a D2/3R agonist ligand from the aminomethyl chromane (AMC) class-(R)-2-[(4- 18Fluorobenzylamino)methyl]chroman-7-ol (18F-AMC20). Methods: In vitro affinities of AMC20 toward dopaminergic receptor subtypes were measured in membrane homogenates prepared from HEK293 cells expressing h…
Interference of left and right cerebellar rTMS with procedural learning.
2004
Abstract Increasing evidence suggests cerebellar involvement in procedural learning. To further analyze its role and to assess whether it has a lateralized influence, in the present study we used a repetitive transcranial magnetic stimulation interference approach in a group of normal subjects performing a serial reaction time task. We studied 36 normal volunteers: 13 subjects underwent repetitive transcranial magnetic stimulation on the left cerebellum and performed the task with the right (6 subjects) or left (7 subjects) hand; 10 subjects underwent repetitive transcranial magnetic stimulation on the right cerebellum and performed the task with the hand ipsilateral (5 subjects) or contral…