Nicolas Mallet

Nicolas Mallet
Institute of Neurodegenerative diseases, University of Bordeaux · CNRS UMR 5293

PhD

About

38
Publications
6,425
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3,174
Citations
Education
September 2002 - December 2005
University of Bordeaux
Field of study
  • Neuroscience

Publications

Publications (38)
Article
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Graphical Abstract Highlights d STR and STN inputs are differentially integrated by Proto and Arky GPe neurons d Axon collaterals of Proto GPe neurons form a disynaptic circuit motif within the GPe d STR inputs can gate the synaptic integration of STN inputs by Arky GPe neurons d Disynaptic disinhibition of Arky GPe neurons supports global motor su...
Preprint
Basal ganglia (BG) inhibit movement through two independent pathways, the indirect- and the hyperdirect-pathways. The globus pallidus (GP) has always been viewed as a simple relay within these two pathways, but its importance has changed drastically with the discovery of two functionally-distinct cell types, namely the prototypic and the arkypallid...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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The dynamical properties of cortico-basal ganglia (CBG) circuits are dramatically altered following the loss of dopamine in Parkinson’s disease (PD). The neural circuit dysfunctions associated with PD include spike-rate alteration concomitant with excessive oscillatory spike-synchronization in the beta frequency range (12–30 Hz). Which neuronal cir...
Article
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Striatal cholinergic interneurons (CINs) are the main source of acetylcholine in the striatum and are believed to play an important role in basal ganglia physiology and pathophysiology. The role of CINs in striatal function is known mostly from extracellular recordings of tonically active striatal neurons in monkeys, which are believed to correspon...
Article
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The basal ganglia (BG) are a collection of interconnected subcortical nuclei that participate in a great variety of functions, ranging from motor programming and execution to procedural learning, cognition, and emotions. This network is also the region primarily affected by the degeneration of midbrain dopaminergic neurons localized in the substant...
Article
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Beta frequency oscillations (15 to 35 Hz) in cortical and basal ganglia circuits become abnormally synchronized in Parkinson’s disease (PD). How excessive beta oscillations emerge in these circuits is unclear. We addressed this issue by defining the firing properties of basal ganglia neurons around the emergence of cortical beta bursts (β bursts),...
Preprint
Full-text available
Prevalence and temporal dynamics of transient oscillations in the beta frequency band (15-35 Hz), referred to as beta bursts, are correlated with motor performance and tactile perception. Disturbance of these activities is a candidate mechanism for motor impairment in Parkinson's disease (PD), where the excessively long bursts correlate with sympto...
Preprint
Brief epochs of beta oscillations have been implicated in sensorimotor control in the basal ganglia of task-performing healthy animals. However, which neural processes underlie their generation and how they are affected by sensorimotor processing remains unclear. To determine the mechanisms underlying transient beta oscillations in the local field...
Article
Brief epochs of beta oscillations have been implicated in sensorimotor control in the basal ganglia of task-performing healthy animals. However, which neural processes underlie their generation and how they are affected by sensorimotor processing remains unclear. To determine the mechanisms underlying transient beta oscillations in the local field...
Article
The suppression of inappropriate actions is critical for flexible behavior. Cortical-basal ganglia networks provide key gating mechanisms for action suppression, yet the specific roles of neuronal subpopulations are poorly understood. Here, we examine Arkypallidal (“Arky”) and Prototypical (“Proto”) globus pallidus neurons during a Stop task, which...
Article
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Studies in dopamine-depleted rats indicate that the external globus pallidus (GPe) contains two main types of GABAergic projection cell; so-called “prototypic” and “arkypallidal” neurons. Here, we used correlative anatomical and electrophysiological approaches in rats to determine whether and how this dichotomous organization applies to the dopamin...
Article
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The development of methodology to identify specific cell populations and circuits within the basal ganglia is rapidly transforming our ability to understand the function of this complex circuit. This mini-symposium highlights recent advances in delineating the organization and function of neural circuits in the external segment of the globus pallid...
Article
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Background A systematic search of brain nuclei putatively involved in L-3,4-dihydroxyphenylalanine (L-Dopa)-induced dyskinesia (LID) in Parkinson’s disease (PD) shed light, notably, upon the lateral habenula (LHb), which displayed an overexpression of the ∆FosB, ARC and Zif-268 immediate-early genes only in rats experiencing abnormal involuntary mo...
Article
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In Parkinsonism, subthalamic nucleus (STN) neurons and two types of external globus pallidus (GP) neuron inappropriately synchronise their firing in time with slow (~1 Hz) or beta (13-30 Hz) oscillations in cortex. We recorded the activities of STN, Type-I GP (GP-TI) and Type-A GP (GP-TA) neurons in anaesthetised Parkinsonian rats during such oscil...
Article
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Salient cues can prompt the rapid interruption of planned actions. It has been proposed that fast, reactive behavioral inhibition involves specific basal ganglia pathways, and we tested this by comparing activity in multiple rat basal ganglia structures during performance of a stop-signal task. Subthalamic nucleus (STN) neurons exhibited low-latenc...
Article
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The striatum is comprised of medium-sized spiny projection neurons (MSNs) and several types of interneuron, and receives massive glutamatergic input from the cerebral cortex. Understanding of striatal function requires definition of the electrophysiological properties of neurochemically identified interneurons sampled in the same context of ongoing...
Article
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Different striatal projection neurons are the origin of a dual organization essential for basal ganglia function. We have defined an analogous division of labor in the external globus pallidus (GPe) of Parkinsonian rats, showing that the distinct temporal activities of two populations of GPe neuron in vivo are underpinned by distinct molecular prof...
Article
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The firing activity of dorsal raphe neurons is related to arousal state. However, it is unclear how this firing activity is precisely related to cortical activity, in particular oscillations occurring during sleep rhythms. Here we conducted single-cell extracellular recordings and juxtacellular labelling while monitoring electrocorticogram (ECoG) a...
Data
Additional model comparison, sensitivity analyses and robustness estimates. This explores a possible model space using Bayesian model comparison and presents additional sensitivity and robustness analyses that support our main conclusions. (DOC)
Article
Abnormal oscillatory synchrony is increasingly acknowledged as a pathophysiological hallmark of Parkinson's disease, but what promotes such activity remains unclear. We used novel, nonlinear time series analyses and information theory to capture the effects of dopamine depletion on directed information flow within and between the subthalamic nucleu...
Article
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Cortico-basal ganglia-thalamocortical circuits are severely disrupted by the dopamine depletion of Parkinson's disease (PD), leading to pathologically exaggerated beta oscillations. Abnormal rhythms, found in several circuit nodes are correlated with movement impairments but their neural basis remains unclear. Here, we used dynamic causal modelling...
Chapter
The striatum is the main input structure of the basal ganglia (BG) [1]. Because it receives massive excitatory inputs from the cortex and mainly projects to deeper BG nuclei, the treatment and transmission of cortical inputs by striatal neurons represent a crucial step in the cortex–BG–thalamus feedback loops. Moreover, the striatum is the brain ar...
Article
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Dopamine depletion in cortical-basal ganglia circuits in Parkinson's disease (PD) grossly disturbs movement and cognition. Classic models relate Parkinsonian dysfunction to changes in firing rates of basal ganglia neurons. However, disturbances in other dynamics of neural activity are also common. Taking both inappropriate firing rates and other dy...
Article
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Inappropriately synchronized beta (beta) oscillations (15-30 Hz) in the subthalamic nucleus (STN) accompany movement difficulties in idiopathic Parkinson's disease (PD). The cellular and network substrates underlying these exaggerated beta oscillations are unknown but activity in the external globus pallidus (GP), which forms a candidate pacemaker...
Article
Striatonigral and striatopallidal neurons form distinct populations of striatal projection neurons. Their discharge activity is imbalanced after dopaminergic degeneration in Parkinson's disease. Striatal projection neurons receive massive cortical excitatory inputs from bilateral intratelencephalic (IT) neurons projecting to both the ipsilateral an...
Article
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In the subthalamic nucleus (STN) of Parkinson's disease (PD) patients, a pronounced synchronization of oscillatory activity at beta frequencies (15-30 Hz) accompanies movement difficulties. Abnormal beta oscillations and motor symptoms are concomitantly and acutely suppressed by dopaminergic therapies, suggesting that these inappropriate rhythms mi...
Article
Prefrontal cortical (PFC) pyramidal neurons (PN) and fast spiking interneurons (FSI) receive dopaminergic (DA) and non-DA inputs from the ventral tegmental area (VTA). Although the responses of PN to VTA stimulation and DA administration have been extensively studied, little is known about the response of FSI to mesocortical activation. We explored...
Article
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The striatum receives massive cortical excitatory inputs and is densely innervated by dopamine. Striatal projection neurons form either the direct or indirect pathways. Models of Parkinson's disease propose that dopaminergic degeneration imbalances both pathways, although direct electrophysiological evidence is lacking. Here, striatal neurons were...
Article
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Discharge activities and local field potentials were recorded in the orofacial motor cortex and in the corresponding rostrolateral striatum of urethane-anesthetized rats. Striatal projection neurons were identified by antidromic activation and fast-spiking GABAergic interneurons (FSIs) by their unique characteristics: briefer spike and burst respon...
Article
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The rapid delivery of drugs of abuse to the brain is thought to promote addiction, but why this occurs is unknown. In the present study, we characterized the influence of rate of intravenous cocaine infusion (5-100 sec) on three effects thought to contribute to its addiction liability: its ability to block dopamine (DA) uptake, to activate immediat...