Search results for "Ganglia"
showing 10 items of 195 documents
Meta-analysis of real-time fMRI neurofeedback studies using individual participant data: How is brain regulation mediated?
2015
An increasing number of studies using real-time fMRI neurofeedback have demonstrated that successful regulation of neural activity is possible in various brain regions. Since these studies focused on the regulated region(s), little is known about the target-independent mechanisms associated with neurofeedback-guided control of brain activation, i.e. the regulating network. While the specificity of the activation during self-regulation is an important factor, no study has effectively determined the network involved in self-regulation in general. In an effort to detect regions that are responsible for the act of brain regulation, we performed a post-hoc analysis of data involving different ta…
Understanding the Significance of the Hypothalamic Nature of the Subthalamic Nucleus
2021
AbstractThe subthalamic nucleus (STN) is an essential component of the basal ganglia and has long been considered to be a part of the ventral thalamus. However, recent neurodevelopmental data indicated that this nucleus is of hypothalamic origin which is now commonly acknowledged. In this work, we aimed to verify whether the inclusion of the STN in the hypothalamus could influence the way we understand and conduct research on the organization of the whole ventral and posterior diencephalon. Developmental and neurochemical data indicate that the STN is part of a larger glutamatergic posterior hypothalamic region that includes the premammillary and mammillary nuclei. The main anatomic charact…
Selective Activation of Serotonin2C Receptors Stimulates GABA-ergic Function in the Rat Substantia Nigra Pars Reticulata: A Combined in Vivo Electrop…
2007
In vivo electrophysiology and microdialysis were used to investigate the physiological role of 5-HT2C receptors in the control of substantia nigra pars reticulata (SNr) function. Extracellular single-unit recordings were performed from putative GABA-containing neurons in the SNr of anesthetized rats, and local GABA release was studied by in vivo microdialysis in the SNr of awake freely-moving rats. Systemic administration of the selective 5-HT2C receptor agonist (S)-2-(chloro-5-fluoro-indol-1-yl)-1-methylethylamine 1:1 C4H4O4 (RO 60-0175) caused a dose-dependent excitation of about 30% of the SNr neurons recorded. However, the remaining neurons were either inhibited or unaffected by systemi…
Electrophysiological and Neurochemical Characterization of 7-Nitroindazole and Molsidomine Acute and Sub-Chronic Administration Effects in the Dopami…
2009
Nitric oxide (NO) plays an important role in the integration of information processed by the basal ganglia nuclei. Accordingly, considerable evidence has emerged indicating a role for NO in pathophysiological conditions such as Parkinson’s disease (PD) and other neurodegenerative disorders. Despite these recent advances, the nitrergic modulation of the dopamine (DA) nigrostriatal system is still unclear. In order to fill this gap, in this study we used in vivo electrophysiology and ex vivo neurochemical analysis to further investigate the effect of NO signaling in rat substantia nigra pars compacta (SNc) and the striatum. Acute and subchronic (4 days) pharmacological manipulation of the NO …
Effects of electrical stimulation of the superior cervical ganglia on the number of ?synaptic? ribbons and the activity of melatonin-forming enzymes …
1989
Melatonin metabolism in the mammalian pineal gland is under the clear influence of sympathetic fibers originating in the superior cervical ganglia (SCG). Previous studies suggested that pineal "synaptic" ribbons (SR) as well are regulated by the gland's sympathetic innervation. To gain more insight into the mechanisms involved, we examined the effects of sympathetic stimulation on SR number and on the activity of melatonin forming enzymes, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). The SCG in adult male rats were stimulated electrically during daytime for either 15 or 120 min. Immediately following stimulation, the glands were removed and processed fo…
Pre- and intraoperative methods of controlling cerebral circulation in giant aneurysm surgery.
1995
The surgical treatment of giant aneurysms usually requires temporary clipping of the aneurysmatic vessel. In planning the surgical approach and in applying temporary clips, the surgeon must consider collateral circulations. The functional integrity of the collateral vessels frequently decides the patient's outcome. In 8 patients with internal carotid artery giant aneurysm, measurements of blood flow velocities in the ipsilateral middle cerebral artery were performed preoperatively with transcranial Doppler ultrasound (TCD) during manual occlusion of the carotid artery at the neck. Three different perfusion patterns were established, and each collateral capacity was rated as insufficient, te…
Extraction of prefronto-amygdalar pathways by combining probability maps
2008
Many recent studies reported altered functional connectivity within the frontolimbic circuitry in a wide range of neuropsychiatric disorders. However, functional connectivity must rely on structural connections. In this study we applied a novel probabilistic fiber tracking method to assess the structural connectivity between the amygdala and different prefrontal brain regions in vivo. Twenty healthy subjects were investigated with diffusion tensor imaging. Probabilistic fiber tracking was started from the amygdala and different prefrontal brain regions. Resulting probability maps were combined using an extended multiplication of probabilistic maps to identify the most probable anatomical pa…
Radiological anatomy assessment of the fissura pterygomaxillaris for a surgical approach to ganglion pterygopalatinum
2017
The ganglion pterygopalatinum has become a therapeutic target to treat various pain syndromes in recent years. It is located in the fossa pterygopalatina, and the fissura pterygomaxillaris is the main access to surgically approach this structure. Recently, the neuromodulation of the ganglion pterygopalatinum by microstimulator implantation has become the first therapeutic line in refractory cluster headache treatment. This invasive technique is performed transorally through the fissura pterygomaxillaris, and is limited by the size of the implantation device, which requires an opening of at least 2 mm. Therefore, extensive knowledge about the anatomy of the fissura pterygomaxillaris prior to…
Ventral striatal prediction error signaling is associated with dopamine synthesis capacity and fluid intelligence.
2012
Fluid intelligence represents the capacity for flexible problem solving and rapid behavioral adaptation. Rewards drive flexible behavioral adaptation, in part via a teaching signal expressed as reward prediction errors in the ventral striatum, which has been associated with phasic dopamine release in animal studies. We examined a sample of 28 healthy male adults using multimodal imaging and biological parametric mapping with 1) functional magnetic resonance imaging during a reversal learning task and 2) in a subsample of 17 subjects also with positron emission tomography using 6-[18F]fluoro-L-DOPA to assess dopamine synthesis capacity. Fluid intelligence was measured using a battery of nine…
'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET inves…
2006
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron‐emission‐tomography (PET) studies, net blood‐brain clearance of [(18)F]‐fluoro‐l‐DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood‐brain clearance of FDOPA (K [Formula: see text]) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes‐of‐interest. The Wisconsin‐Card‐Sorting‐Test (WCST), Stroop‐T…