Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

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 nucleus (STN) and external globus pallidus (GPe). We compared neuronal activity recorded simultaneously from these nuclei in 6-hydroxydopamine-lesioned Parkinsonian rats with that in dopamine-intact control rats. After lesioning, both nuclei displayed pronounced augmentations of beta-frequency (∼20 Hz) oscillations and, critically, information transfer between STN and GPe neurons was increased. Furthermore, temporal profiles of the directed information transfer agreed with the neurochemistry of these nuclei, being "excitatory" from STN to GPe and "inhibitory" from GPe to STN. Separation of the GPe population in lesioned animals into "type-inactive" (GP-TI) and "type-active" (GP-TA) neurons, according to definitive firing preferences, revealed distinct temporal profiles of interaction with STN and each other. The profile of GP-TI neurons suggested their output is of greater causal significance than that of GP-TA neurons for the reduced activity that periodically punctuates the spiking of STN neurons during beta oscillations. Moreover, STN was identified as a key candidate driver for recruiting ensembles of GP-TI neurons but not GP-TA neurons. Short-latency interactions between GP-TI and GP-TA neurons suggested mutual inhibition, which could rhythmically dampen activity and promote anti-phase firing across the two subpopulations. Results thus indicate that information flow around the STN-GPe circuit is exaggerated in Parkinsonism and further define the temporal interactions underpinning this.

Original publication

DOI

10.1152/jn.00094.2011

Type

Journal article

Journal

J Neurophysiol

Publication Date

10/2011

Volume

106

Pages

2012 - 2023

Keywords

Action Potentials, Animals, Dopamine, Dopamine Antagonists, Dopaminergic Neurons, Globus Pallidus, Male, Models, Neurological, Nerve Net, Neural Pathways, Nonlinear Dynamics, Oxidopamine, Parkinsonian Disorders, Rats, Rats, Sprague-Dawley, Subthalamic Nucleus, Time Factors