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Takashi Hashido, Shigeyoshi Saito
PURPOSE: Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T1, T2, and T2* mapping of the lower midbrain. METHODS: The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6.9 years). Neuromelanin-sensitive MRI was acquired using an optimized T1-weighted two-dimensional (2D)-turbo spin-echo sequence...
2016: PloS One
Kenneth S Henry, Kristina S Abrams, Johanna Forst, Matthew J Mender, Erikson G Neilans, Fabio Idrobo, Laurel H Carney
Vowels make a strong contribution to speech perception under natural conditions. Vowels are encoded in the auditory nerve primarily through neural synchrony to temporal fine structure and to envelope fluctuations rather than through average discharge rate. Neural synchrony is thought to contribute less to vowel coding in central auditory nuclei, consistent with more limited synchronization to fine structure and the emergence of average-rate coding of envelope fluctuations. However, this hypothesis is largely unexplored, especially in background noise...
October 20, 2016: Journal of the Association for Research in Otolaryngology: JARO
Julie M Hall, Kaylena A Ehgoetz Martens, Courtney C Walton, Claire O'Callaghan, Peter E Keller, Simon J G Lewis, Ahmed A Moustafa
Parkinson's disease (PD) is a heterogeneous neurological disorder with a variety of motor and non-motor symptoms. The underlying mechanisms of these symptoms are not fully understood. An increased interest in structural connectivity analyses using diffusion tensor imaging (DTI) in PD has led to an expansion of our understanding of the impact of abnormalities in diffusivity on phenotype. This review outlines the contribution of these abnormalities to symptoms of PD including bradykinesia, tremor and non-tremor phenotypes, freezing of gait, cognitive impairment, mood, sleep disturbances, visual hallucinations and olfactory dysfunction...
September 28, 2016: Parkinsonism & related Disorders
Thomas Viereckel, Sylvie Dumas, Casey J A Smith-Anttila, Bianca Vlcek, Zisis Bimpisidis, Malin C Lagerström, Åsa Konradsson-Geuken, Åsa Wallén-Mackenzie
The ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) of the midbrain are associated with Parkinson's disease (PD), schizophrenia, mood disorders and addiction. Based on the recently unraveled heterogeneity within the VTA and SNc, where glutamate, GABA and co-releasing neurons have been found to co-exist with the classical dopamine neurons, there is a compelling need for identification of gene expression patterns that represent this heterogeneity and that are of value for development of human therapies...
October 20, 2016: Scientific Reports
Elsa Vera, Nazario Bosco, Lorenz Studer
Modeling late-onset disorders such as Parkinson's disease (PD) using iPSC technology remains a challenge, as current differentiation protocols yield cells with the properties of fetal-stage cells. Here, we tested whether it is possible to accelerate aging in vitro to trigger late-onset disease phenotypes in an iPSC model of PD. In order to manipulate a factor that is involved in natural aging as well as in premature aging syndromes, we used telomere shortening as an age-inducing tool. We show that shortened telomeres result in age-associated as well as potentially disease-associated phenotypes in human pluripotent stem cell (hPSC)-derived midbrain dopamine (mDA) neurons...
October 18, 2016: Cell Reports
Hideyuki Matsumoto, Ju Tian, Naoshige Uchida, Mitsuko Watabe-Uchida
Dopamine is thought to regulate learning from appetitive and aversive events. Here we examined how optogenetically-identified dopamine neurons in the lateral ventral tegmental area of mice respond to aversive events in different conditions. In low reward contexts, most dopamine neurons were exclusively inhibited by aversive events, and expectation reduced dopamine neurons' responses to reward and punishment. When a single odor predicted both reward and punishment, dopamine neurons' responses to that odor reflected the integrated value of both outcomes...
October 19, 2016: ELife
Kyu-Man Han, Daseul Kim, Youngbo Sim, June Kang, Aram Kim, Eunsoo Won, Woo-Suk Tae, Byung-Joo Ham
BACKGROUND: Morphologic changes of the brainstem in major depressive disorder (MDD) have rarely been reported in neuroimaging studies, even though, monoaminergic neurotransmitters are synthesized in several brainstem regions. We aimed to investigate volume changes in each region of the brainstem and their association with antidepressant use or the remission status of MDD. METHODS: A total of 126 patients with MDD and 101 healthy controls underwent T1-weighted structural magnetic resonance imaging...
October 11, 2016: Journal of Affective Disorders
Linde Boekhoudt, Elisa S Voets, Jacques P Flores-Dourojeanni, Mieneke Cm Luijendijk, Louk Jmj Vanderschuren, Roger Ah Adan
Attentional impairments and exaggerated impulsivity are key features of psychiatric disorders, such as attention-deficit/hyperactivity disorder, schizophrenia, and addiction. These deficits in attentional performance and impulsive behaviours have been associated with aberrant dopamine (DA) signalling, but it remains unknown whether these deficits result from enhanced DA neuronal activity in the midbrain. Here, we took a novel approach by testing the impact of chemogenetically activating DA neurons in the ventral tegmental area (VTA) or substantia nigra pars compacta (SNc) on attention and impulsivity in the five-choice serial reaction time task (5-CSRTT) in rats...
October 17, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Jonathan C Niclis, Carlos W Gantner, Walaa F Alsanie, Stuart J McDougall, Chris R Bye, Andrew G Elefanty, Edouard G Stanley, John M Haynes, Colin W Pouton, Lachlan H Thompson, Clare L Parish
: : Recent studies have shown evidence for the functional integration of human pluripotent stem cell (hPSC)-derived ventral midbrain dopamine (vmDA) neurons in animal models of Parkinson's disease. Although these cells present a sustainable alternative to fetal mesencephalic grafts, a number of hurdles require attention prior to clinical translation. These include the persistent use of xenogeneic reagents and challenges associated with scalability and storage of differentiated cells. In this study, we describe the first fully defined feeder- and xenogeneic-free protocol for the generation of vmDA neurons from hPSCs and utilize two novel reporter knock-in lines (LMX1A-eGFP and PITX3-eGFP) for in-depth in vitro and in vivo tracking...
October 14, 2016: Stem Cells Translational Medicine
Shubir Dutt, Richard J Binney, Hilary W Heuer, Phi Luong, Suneth Attygalle, Priyanka Bhatt, Gabe A Marx, Jonathan Elofson, Maria C Tartaglia, Irene Litvan, Scott M McGinnis, Bradford C Dickerson, John Kornak, Dana Waltzman, Lisa Voltarelli, Norbert Schuff, Gil D Rabinovici, Joel H Kramer, Clifford R Jack, Bruce L Miller, Howard J Rosen, Adam L Boxer
OBJECTIVE: To examine the utility and reliability of volumetric MRI in measuring disease progression in the 4 repeat tauopathies, progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS), to support clinical development of new tau-directed therapeutic agents. METHODS: Six- and 12-month changes in regional MRI volumes and PSP Rating Scale scores were examined in 55 patients with PSP and 33 patients with CBS (78% amyloid PET negative) compared to 30 normal controls from a multicenter natural history study...
October 14, 2016: Neurology
Bumpei Samata, Daisuke Doi, Kaneyasu Nishimura, Tetsuhiro Kikuchi, Akira Watanabe, Yoshimasa Sakamoto, Jungo Kakuta, Yuichi Ono, Jun Takahashi
Human induced pluripotent stem cells (iPSCs) can provide a promising source of midbrain dopaminergic (mDA) neurons for cell replacement therapy for Parkinson's disease (PD). However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. To eliminate these unwanted cells, cell sorting using antibodies for specific markers such as CORIN or ALCAM has been developed, but neither marker is specific for ventral midbrain. Here we employ a double selection strategy for cells expressing both CORIN and LMX1A::GFP, and report a cell surface marker to enrich mDA progenitors, LRTM1...
October 14, 2016: Nature Communications
Christine K Wagner, Princy Quadros-Mennella
Steroid hormones activate nuclear receptors which, as transcription factors, can regulate critical aspects of neural development. Many regions of the rat forebrain, midbrain and hindbrain express progestin receptors (PR) during perinatal life, suggesting that progesterone may play an important role in the development of the brain. An immunohistochemical approach using two antibodies with differential recognition of ligand-bound PR was used to examine whether fetuses are exposed to maternal progesterone during pregnancy and whether progesterone from maternal circulation can bind to PR within the fetal brain...
October 14, 2016: Developmental Neurobiology
Maike Vollmer, Ralph Eugene Beitel, Christoph E Schreiner, Patricia A Leake
In profoundly deaf cats, behavioral training with intracochlear electric stimulation (ICES) can improve temporal processing in the primary auditory cortex (AI). To investigate whether similar effects are manifest in the auditory midbrain, ICES was initiated in neonatally deafened cats either during development after short durations of deafness (8 wk of age) or in adulthood after long durations of deafness (≥3.5 yr). All of these animals received behaviorally-meaningless, 'passive' ICES. Some animals also received behavioral training with ICES...
October 12, 2016: Journal of Neurophysiology
Mihee Song, Yong Sang Jo, Yeon-Kyung Lee, June-Seek Choi
The lateral habenula (LHb) is an epithalamic brain structure that provides strong projections to midbrain monoaminergic systems that are involved in motivation, emotion, and reinforcement learning. LHb neurons are known to convey information about aversive outcomes and negative prediction errors, suggesting a role in learning from aversive events. To test this idea, we examined the effects of electrolytic lesions of the LHb on signaled two-way active avoidance learning in which rats were trained to avoid an unconditioned stimulus (US) by taking a proactive shuttling response to an auditory conditioned stimulus (CS)...
October 9, 2016: Behavioural Brain Research
Nivedita Bhattacharjee, Anupom Borah
Homocysteine (Hcy) when injected intranigrally in rat caused parkinsonian behavioural phenotypes and loss of nigral dopaminergic neurons but the underlying mechanisms of neurotoxicity remains elusive. In the present study, we focused on oxidative stress as one of the mechanisms of neurotoxicity in Hcy-induced hemiparkinsonian rat model. Unilateral intranigral infusion of Hcy (1.0 μmol in 2 μl) caused inhibition of mitochondrial complex-I activity, decrease in the level of striatal dopamine, loss of midbrain dopaminergic neurons, and motor abnormalities...
October 9, 2016: Neurochemistry International
Hongxiang Sun, Xiuquan He, Cejia Liu, Lingyu Li, Ruoyu Zhou, Tianyun Jin, Su Yue, Da Feng, Jie Gong, Jiawei Sun, Jianbo Ji, Lan Xiang
Oleracein E (OE), a tetrahydroisoquinoline possessing potent anti-oxidant activity, was first isolated from a traditional Chinese medicine, Portulaca oleraea L., and is hypothesized to be a neuroprotectant. In the present study, we evaluated the effects of racemic OE on rotenone-induced toxicity in Parkinson's disease (PD) cell and animal models. Pre-treatment with OE (10 μM, 2 h) decreased LDH release and the apoptosis rate in rotenone (5 μM, 24 h)-treated SH-SY5Y human neuroblastoma cells. Further mechanistic study indicated that OE reduced reactive oxygen species (ROS) levels, inhibited ERK1/2 phosphorylation, reduced rotenone-induced up-regulation of the proapoptotic protein Bax, and prevented cytochrome C release and caspase-3 activation...
October 12, 2016: ACS Chemical Neuroscience
Jingjing He, Zheng Xiang, Xiaoqing Zhu, Zongyong Ai, Jingsong Shen, Tianzhuang Huang, Liegang Liu, Weizhi Ji, Tianqing Li
Parkinson's disease (PD) is one common neurodegenerative disease caused by a significant loss of midbrain dopaminergic neurons. Previous reports showed that 7, 8- dihydroxyflavone (7, 8-DHF) as a potent TrkB agonist can mimic BDNF and play neuroprotective roles for mouse dopaminergic neurons. Nonetheless, the safety and neuroprotective effects are unclear in monkey models of PD. Here, we find that 7, 8-DHF could be absorbed and metabolized into 7-hydroxy-8-methoxyflavone through oral administration in monkeys...
October 12, 2016: Scientific Reports
Satoshi Ota, Kiyohito Taimatsu, Kanoko Yanagi, Tomohiro Namiki, Rie Ohga, Shin-Ichi Higashijima, Atsuo Kawahara
The CRISPR/Cas9 complex, which is composed of a guide RNA (gRNA) and the Cas9 nuclease, is useful for carrying out genome modifications in various organisms. Recently, the CRISPR/Cas9-mediated locus-specific integration of a reporter, which contains the Mbait sequence targeted using Mbait-gRNA, the hsp70 promoter and the eGFP gene, has allowed the visualization of the target gene expression. However, it has not been ascertained whether the reporter integrations at both targeted alleles cause loss-of-function phenotypes in zebrafish...
October 11, 2016: Scientific Reports
Balachandar Radhakrishnan, A Alwin Prem Anand
MicroRNAs (miRNAs) are a class of small regulatory RNAs involved in gene regulation. The regulation is effected by either translational inhibition or transcriptional silencing. In vertebrates, the importance of miRNA in development was discovered from mice and zebrafish dicer knockouts. The miRNA-9 (miR-9) is one of the most highly expressed miRNAs in the early and adult vertebrate brain. It has diverse functions within the developing vertebrate brain. In this article, the role of miR-9 in the developing forebrain (telencephalon and diencephalon), midbrain, hindbrain, and spinal cord of vertebrate species is highlighted...
2016: Journal of Experimental Neuroscience
Oliver D Howes, Robert McCutcheon, Michael J Owen, Robin M Murray
The dopamine hypothesis is the longest standing pathoetiologic theory of schizophrenia. Because it was initially based on indirect evidence and findings in patients with established schizophrenia, it was unclear what role dopamine played in the onset of the disorder. However, recent studies in people at risk of schizophrenia have found elevated striatal dopamine synthesis capacity and increased dopamine release to stress. Furthermore, striatal dopamine changes have been linked to altered cortical function during cognitive tasks, in line with preclinical evidence that a circuit involving cortical projections to the striatum and midbrain may underlie the striatal dopamine changes...
August 6, 2016: Biological Psychiatry
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