Topic: external globus pallidus

An increase in beta-band frequency (13-30 Hz) activity has been observed in different nuclei of the basal ganglia (BG) of patients with Parkinson's disease (PD). However, recent studies have shown that beta oscillations are not only specific to pathological conditions. They have been shown to occur during sensorimotor tasks in healthy subjects. In this study, we used both a rate model and a spiking neural network to investigate the mechanisms responsible for the generations of beta oscillations. Results show that using a rate model with realistic time constants, the classical candidate - a rec

The basal ganglia are a network of subcortical nuclei that play a central role in regulating motor and cognitive functions. A critical hub in these structures is the external globus pallidus (GPe) as it links all nuclei in this network. This nucleus was long considered a homogenous relay in the motor-suppressing indirect pathway. However, the GPe is anatomically and functionally diverse. How the GPe subpopulations contribute differentially to cognitive and motor function is currently unknown. Here, we find (1) that the GPe encodes motor and value signals in distinct subpopulations, (2) that th

The external Globus Pallidus (GPe) is a central hub in the basal ganglia. This structure is composed mainly of GABAergic neurons, which are divided into two distinct subtypes called: prototypic (70%) and arkypallidal (ARKY: 20%) neurons differentiated by their molecular and electrophysiological signatures. ARKY neurons project exclusively to the striatum and send a stop signal that interrupt ongoing action, suggesting their key role in movement control. However, little is known about the contribution of ARKY neurons to the pathophysiology of Parkinson’s Disease (PD). Moreover, it has been rece

Basal ganglia (BG) circuits are crucial for motor initiation and suppression. Dopamine loss in these circuits triggers Parkinson's disease (PD) and debilitating motor impairments such as akinesia and bradykinesia. Levodopa treatments alleviates PD symptoms, but often leads to abnormal involuntary movements known as levodopa-induced dyskinesias (LIDs). Understanding the neuronal mechanism of LIDs is essential for developing novel therapeutic strategies. Recent studies suggest that LIDs result from abnormal striatal activity, yet how this activity affects downstream BG circuits to generate LIDs

The striatum constitutes the main input structure of the basal ganglia and is mainly composed of GABAergic medium spiny neurons (MSNs) giving rise to the direct and indirect pathways. An additional compartmentalization of the striatum, consisting in the striosomes and the matrix was described decades ago. The respective network organization and functions of these compartments are much less understood along with the differences in their MSNs intrinsic properties. Our aim is to assess the intrinsic properties of the striosomal and matrix neurons and to characterize their functional connectivity.

The classical model of basal ganglia (BG) network emphasizes a functional organization centered around the striatum and subthalamic nucleus as the main receiving areas of excitatory cortical inputs. However, recent anatomical studies revealed direct input projections from the cortex to the external globus pallidus (GPe) in many species including humans, suggesting that GPe also provides an entry for cortical information to the BG. When and how top-down cortical control of GPe takes place to support motor and cognitive functions remain an open question. Using an optogenetic approach, we first e

Parkinson’s disease (PD) is characterized by the loss of dopamine in the basal ganglia (BG), particularly in the striatum, leading to aberrant activity patterns in BG neuronal circuits. The external globus pallidus (GPe) is a central nucleus in the BG and plays a pivotal role in the function of the indirect pathway. two populations of GPe cells were described, the prototypic and arkypallidal neurons, which are distinct developmentally, anatomically and electrophysiologically. Additionally, they have been shown to be involved in sensory processing, mediated by different input pathways. How dopa

Decision-making is a higher-order brain function that consists in choosing between behaviors/options. Basal ganglia (BG) dysfunction is known to be involved in decision-making deficits observed in patients suffering from BG-related disorders including neurological (e.g., Parkinson's disease) and psychiatric (e.g., obsessive compulsive disorders) disorders. However, the neural mechanisms and computations of decision-making in BG network are elusive and do not satisfactorily reflect the complex and known BG anatomy and physiology. Moreover, there are different types of value-related information