Search results for "Putamen"

Opiate-induced dopamine release is modulated by severity of alcohol dependence: an [(18)F]fallypride positron emission tomography study.

2011

Background Preclinical data implicate the reinforcing effects of alcohol to be mediated by interaction between the opioid and dopamine systems of the brain. Specifically, alcohol-induced release of β-endorphins stimulates μ-opioid receptors (MORs), which is believed to cause dopamine release in the brain reward system. Individual differences in opioid or dopamine neurotransmission have been suggested to be responsible for enhanced liability to abuse alcohol. In the present study, a single dose of the MOR agonist remifentanil was administered in detoxified alcohol-dependent patients and healthy control subjects to mimic the β-endorphin-releasing properties of ethanol and to assess the effect…

The Relationship between Gray Matter Quantitative MRI and Disability in Secondary Progressive Multiple Sclerosis

2016

Purpose: In secondary progressive Multiple Sclerosis (SPMS), global neurodegeneration as a driver of disability gains importance in comparison to focal inflammatory processes. However, clinical MRI does not visualize changes of tissue composition outside MS lesions. This quantitative MRI (qMRI) study investigated cortical and deep gray matter (GM) proton density (PD) values and T1 relaxation times to explore their potential to assess neuronal damage and its relationship to clinical disability in SPMS. Materials and Methods: 11 SPMS patients underwent quantitative T1 and PD mapping. Parameter values across the cerebral cortex and deep GM structures were compared with 11 healthy controls, and…

Tonically Active Neurons in the Monkey Striatum are Sensitive to Sensory Events in a Manner that Reflects their Predictability in Time

2002

It is now well established that tonically active neurons (TANs) in the monkey striatum respond to motivationally relevant sensory events, such as conditioned stimuli to which the animal had to react correctly to obtain reward. Recent findings obtained in our laboratory suggested that stimulus prediction may influence the responsiveness of the TANs. In the present study we specifically investigated the effects of temporal aspects of prediction on the responses of single TANs recorded both in the caudate nucleus and putamen of two macaque monkeys. Three different behavioral situations were employed: (1) an instrumental task, in which a visual stimulus triggering a rewarded movement was preced…

2015

Objective Dopamine is an endogenous neuromodulator in cortical circuits and the basal ganglia. In animal models of temporal lobe epilepsy (TLE), seizure threshold is modulated to some extent by dopamine, with D1-receptors having a pro- and D2-receptors an anticonvulsant effect. We aimed to extend our previously reported results on decreased D2/D3 receptor binding in the lateral epileptogenic temporal lobe and to correlate them with demographic and seizure variables to gain a more comprehensive understanding of the underlying involvement of the dopaminergic system in the epileptogenesis of TLE. Methods To quantify D2/D3 receptor binding, we studied 21 patients with TLE and hippocampal sclero…

[18F]PR04.MZ PET/CT Imaging for Evaluation of Nigrostriatal Neuron Integrity in Patients With Parkinson Disease.

2020

Introduction Degeneration of dopaminergic, nigrostriatal neurons is the hallmark of Parkinson disease (PD), and PET quantification of dopamine transporters is a widely accepted method for differential diagnosis between idiopathic PD and essential tremor. [18F]PR04.MZ is a new PET tracer with excellent imaging properties allowing for precise quantification of striatal and extrastriatal dopamine transporter. Here we describe our initial experience with [18F]PR04.MZ PET/CT in a larger cohort of healthy controls and PD patients as a proof-of-concept study for this tracer. Methods Eighteen healthy subjects, 19 early PD patients (Hoehn-Yahr I–II), and 13 moderate-advanced PD patients (Hoehn-Yahr …

Alterations in striatal neuropeptide mRNA produced by repeated administration of L-DOPA, ropinirole or bromocriptine correlate with dyskinesia induct…

2002

Chronic administration of L-DOPA to MPTP-treated common marmosets induces marked dyskinesia while repeated administration of equivalent antiparkisonian doses of ropinirole and bromocriptine produces only mild involuntary movements. The occurrence of dyskinesia has been associated with an altered balance between the direct and indirect striatal output pathways. Using in situ hybridisation histochemistry, we now compare the effects of these drug treatments on striatal preproenkephalin-A (PPE-A) and adenosine A(2a) receptor mRNA expression as markers of the indirect pathway and striatal preprotachykinin (PPT) mRNA and preproenkephalin-B (PPE-B, prodynorphin) mRNA expression as markers of the d…

Genetic linkage of autosomal dominant progressive supranuclear palsy to 1q31.1

2005

Progressive supranuclear palsy (PSP) is a disorder of unknown pathogenesis. Familial clusters of PSP have been reported related to mutations of protein tau. We report the linkage of a large Spanish family with typical autosomal dominant PSP to a new locus in chromosome 1. Four members of this family had typical PSP, confirmed by neuropathology in one case. At least five ancestors had similar disease. Other members of the family have incomplete phenotypes. The power of the linkage analysis was increased by detecting presymptomatic individuals with 18F-fluoro-dopa and 18F-deoxyglucose positron emission tomography. We screened the human genome with 340 polymorphic markers and we enriched the a…

Bilingualism at the core of the brain. Structural differences between bilinguals and monolinguals revealed by subcortical shape analysis.

2015

Naturally acquiring a language shapes the human brain through a long-lasting learning and practice process. This is supported by previous studies showing that managing more than one language from early childhood has an impact on brain structure and function. However, to what extent bilingual individuals present neuroanatomical peculiarities at the subcortical level with respect to monolinguals is yet not well understood, despite the key role of subcortical gray matter for a number of language functions, including monitoring of speech production and language control — two processes especially solicited by bilinguals. Here we addressed this issue by performing a subcortical surface-based anal…

Increased neuropeptide Y mRNA expression in striatum in Parkinson's disease.

2003

High levels of neuropeptide Y (NPY) are found in basal ganglia where it is co-localised with somatostatin (SOM) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH/d) in a population of striatal GABA containing interneurones. Although alterations occur in the levels of various neuropeptides in basal ganglia in Parkinson’s disease (PD), it is not known whether NPY is affected. Using in situ hybridisation immunohistochemistry, we have examined the distribution of NPY mRNA in the caudate nucleus, putamen and nucleus accumbens of normal individuals and patients with PD. NPY mRNA was weakly expressed in the caudate nucleus, putamen and nucleus accumbens in normal individuals with a…

Synthesis and pharmacology of 6-substituted benztropines: discovery of novel dopamine uptake inhibitors possessing low binding affinity to the dopami…

2005

A series of 6alpha- and 6beta-substituted benztropines were synthesized. A marked enantioselectivity was observed for the 6beta-methoxylated benztropines, the (1R)-isomers being more potent than the corresponding (1S) compounds. The racemic 6alpha-methoxy-3-(4',4' '-difluorodiphenylmethoxy)tropane (5 g) was the most potent compound. It has been found that modifications at the 6-position of benztropine might reduce the DAT binding affinity, maintaining otherwise a significant dopamine uptake inhibitory activity. A reinvestigation of the absolute configuration of 6beta-methoxytropinone proved the 6R configuration for the (+)-enantiomer.