Somatotopy in the basal ganglia: experimental and clinical evidence for segregated sensorimotor channels

Romanelli, Pantaleo; Esposito, Vincenzo; Schaal, David W.; Heit, Gary

doi:10.1016/j.brainresrev.2004.09.008

Cited by 137 publications

(108 citation statements)

References 118 publications

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“…There is ample evidence to suggest that loss of segregation between modules occurs in PD. Physiologically, loss of segregation may originate from the compensatory mechanisms that occur in an attempt to counteract the DA deficiency, such as a larger area of DA diffusion from the surviving neurons, enlarged receptive fields in the striatum, GPi, GPe, STN and thalamus, and increased corticostriatal transmission (Strafella et al 2005;Romanelli et al 2005; Fig. 9 GPi activity (a, b), STN activity (c, d), and angular velocity (e, f), resulting from simulation of the parkinsonian model (DA=0.7) including DBS mechanism 2 (excitation of afferent axons), and 3 (partial synaptic failure), respectively.…”

Section: Discussionmentioning

confidence: 99%

“…The normal mode of DA communication is synaptic transmission. Romanelli et al (2005) have proposed that a loss of functional segregation between BG motor modules may occur in PD patients. In the present study loss of segregation was modelled as originating in the striatum, due to the fact that DA loss mainly affects the striatum and it is known that communication exists between different functional striatal areas via lateral inhibition.…”

Section: Parkinsonian Modelmentioning

confidence: 99%

“…The preservation of body maps throughout the various nuclei of the BG suggests that the BG-thalamocortical circuit is characterised by individual parallel modules, related to specific body parts, spatially segregated in a somatotopic fashion (Romanelli et al 2005;Strafella et al 2005). Furthermore, single cell studies have shown that neurons in the BG are direction-specific (Nambu et al 2002) and fire in relation to movement about a particular joint in a particular limb (Teulings et al 1997).…”

Section: Introductionmentioning

confidence: 99%

“…In neurodegenerative diseases, a certain degree of distortion of the body maps occurs, which is thought to lead to a loss of functional segregation between neurons in neighbouring modules. It has been proposed that a loss of segregation may result in increased difficulty in inhibiting unwanted movements and facilitating desired movements (Romanelli et al 2005;Strafella et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Increased bradykinesia in Parkinson’s disease with increased movement complexity: elbow flexion–extension movements

2008

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The present research investigates factors contributing to bradykinesia in the control of simple and complex voluntary limb movement in Parkinson's disease (PD) patients. The functional scheme of the basal ganglia (BG)-thalamocortical circuit was described by a mathematical model based on the mean firing rates of BG nuclei. PD was simulated as a reduction in dopamine levels, and a loss of functional segregation between two competing motor modules. In order to compare model simulations with performed movements, flexion and extension at the elbow joint is taken as a test case. Results indicated that loss of segregation contributed to bradykinesia due to interference between competing modules and a reduced ability to suppress unwanted movements. Additionally, excessive neurotransmitter depletion is predicted as a possible mechanism for the increased difficulty in performing complex movements. The simulation results showed that the model is in qualitative agreement with the results from movement experiments on PD patients and healthy subjects. Furthermore, based on changes in the firing rate of BG nuclei, the model demonstrated that the effective mechanism of Deep Brain Stimulation (DBS) in STN may result from stimulation induced inhibition of STN, partial synaptic failure of efferent projections, or excitation of inhibitory afferent axons even though the underlying methods of action may be quite different for the different mechanisms.

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Section: Discussionmentioning

confidence: 99%

Section: Parkinsonian Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increased bradykinesia in Parkinson’s disease with increased movement complexity: elbow flexion–extension movements

2008

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“…The BG also involve a third indirect circuit, the indirect pathway, incorporating the external globus pallidus not considered in the model presented here. The pathways of BG-cortical loops tend to form partially segregated channels as their different portions (striatum, GPi/SNr, and STN), and the thalamic regions to which they project, generally preserve the topological organisation of the cortex to which they are connected (Haber, 2003;Romanelli et al, 2005). The organisation into channels of the direct pathway (suitably modulated by the indirect and hyperdirect pathways), has led to wide agreement that the BG are well suited to select secondary perceptual representations, actions, and other more complex cognitive contents when animals face selection problems in these domains Redgrave et al, 1999;Joel et al, 2002).…”

Section: The Biology Underpinning the Modelmentioning

confidence: 99%

Intrinsically motivated action–outcome learning and goal-based action recall: A system-level bio-constrained computational model

et al. 2013

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Reinforcement (trial-and-error) learning in animals is driven by a multitude of processes. Most animals have evolved several sophisticated systems of 'extrinsic motivations' (EMs) that guide them to acquire behaviours allowing them to maintain their bodies, defend against threat, and reproduce. Animals have also evolved various systems of 'intrinsic motivations' (IMs) that allow them to acquire actions in the absence of extrinsic rewards. These actions are used later to pursue such rewards when they become available. Intrinsic motivation has been studied in Psychology for many decades and its biological substrate is now being elucidated by neuroscientists. In the last two decades, investigators in computational modelling, robotics and machine learning have proposed various mechanisms that capture certain aspects of IMs. However, we still lack models of IMs that attempt to integrate all key aspects of intrinsically motivated learning and behaviour while taking into account the relevant neurobiological constraints. This paper proposes a bio-constrained system-level model that contributes a major step towards this integration. The model focusses on three processes related to IMs and on the neural mechanisms underlying them: (a) the acquisition of action-outcome associations (internal models of the agent-environment interaction) driven by phasic dopamine signals caused by sudden, unexpected changes in the environment; (b) the transient focussing of visual gaze and actions on salient portions of the environment; (c) the subsequent recall of actions to pursue extrinsic rewards based on goal-directed reactivation of the representations of their outcomes. The tests of the model, including a series of selective lesions, show how the focussing processes lead to a faster learning of action-outcome associations, and how these associations can be recruited for accomplishing goal-directed behaviours. The model, together with the background knowl-1 edge reviewed in the paper, represents a framework that can be used to guide the design and interpretation of empirical experiments on IMs, and to computationally validate and further develop theories on them.

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Functional Organization of the Basal Ganglia: Dopaminergic and Non‐Dopaminergic Features

Juri

Rodríguez‐Oroz

Obeso

2011

Parkinson's Disease

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Somatotopy in the basal ganglia: experimental and clinical evidence for segregated sensorimotor channels

Cited by 137 publications

References 118 publications

Increased bradykinesia in Parkinson’s disease with increased movement complexity: elbow flexion–extension movements

Increased bradykinesia in Parkinson’s disease with increased movement complexity: elbow flexion–extension movements

Intrinsically motivated action–outcome learning and goal-based action recall: A system-level bio-constrained computational model

Functional Organization of the Basal Ganglia: Dopaminergic and Non‐Dopaminergic Features

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