Browsing by Subject "basal ganglia"

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    Effects of electrical and optogenetic deep brain stimulation on synchronized oscillatory activity in Parkinsonian basal ganglia
    (Office of the Vice Chancellor for Research, 2016-04-08) Ratnadurai-Giridharan, Shivakeshavan; Cheung, Chung C.; Rubchinsky, Leonid L.
    Objective. Deep brain stimulation (DBS) of basal ganglia targets with high-frequency regular electrical pulses is used to treat Parkinsonian motor symptoms. In spite of positive treatment effects, it has a series of limitations. In contrast, optogenetic stimulation, a new but fast growing area, is not yet at a point of clinical testing. Nevertheless, it emerges as an alternative experimental stimulation technique to affect pathological network dynamics, which may be responsible for motor symptoms. This paper compares the effects of electrical and optogenetic stimulation of the basal ganglia on the pathological parkinsonian rhythmic neural activity. Approach. We utilized a conductance-based model of the subthalamo-pallidal circuitry, which reproduces experimentally-observed patterns of neural activity in Parkinson’s disease, and consider the network response to electrical stimulation, excitatory optogenetic stimulation, and inhibitory optogenetic stimulation. Main Results. We found that different simulation types exhibit different interactions with pathological rhythmic activity in the network. We study these interactions for different network and stimulation parameter values. We show that, in the considered model, optogenetic stimulation may be more efficient in suppressing beta oscillations than electrical stimulation. Significance. These results indicate that optogenetic control may be more efficacious than electrical control of a network’s dynamics because of the different ways of how stimulations interact with network dynamics.
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    Modeling the Origin of Parkinsonian Tremor
    (Office of the Vice Chancellor for Research, 2011-04-08) Dovzhenok, Andrei; Rubchinsky, Leonid
    Even though much is known about the biophysics, anatomy and physiology of basal ganglia networks, the cellular and network basis of parkinsonian tremor remains an open question. Multiple experimental data suggest that the physiological origin of parkinsonian tremor is different from the physiological origin of other parkinsonian motor symptoms. However, the exact origin of the tremor genesis in Parkinson’s disease remains unknown. A large body of experimental evidence supports the hypothesis, that the tremor arises due to pathological interaction of potentially oscillatory cells within the loop formed by basal ganglia and thalamocortical circuits. We suggest a model of this circuitry, which helps to clarify this potential mechanism of tremor genesis.