Effect of membrane property modulations by dopamine on synchronous/asynchronous activity in a network of globus pallidus externus
BMC Neuroscience
Poster presentation Effect of membrane property modulations by dopamine on synchronous/asynchronous activity in a network of globus pallidus externus
Katsunori Kitano 2
Tomohiro Fujita 1
Tomoki Fukai 0
0 Brain Science Institute, RIKEN , Wako, Saitama 351-0198 , Japan
1 Graduate School of Science and Engineering, Ritsumeikan University , Kusatsu, Shiga 525-8577 , Japan
2 Department of Human and Computer Intelligence, Ritsumeikan University , Kusatsu, Shiga 525-8577 , Japan
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from Seventeenth Annual Computational Neuroscience Meeting: CNS*2008
Portland, OR, USA. 19–24 July 2008
Introduction
Subthalamic nuclei (STN) and globus pallidus externus
(GPe) are important nuclei for basal ganglia functions
since spatio-temporal patterns of neural activity in the
nuclei have a close relationship with movement disorders
such as Parkinson disease. However, the mechanism of
transition between normal tonic activity and pathological
rhythmical burst activity with changing dopamine levels
has been still unclear. Rebound burst activity of STN
neurons, which is induced by strong hyperpolarization, may
play a key role for such an activity mode transition. On the
other hand, the GPe is a major source of hyperpolarizing
input to the STN. Therefore, an understanding of the
dynamical properties of a GPe network is gaining
importance.
Methods
We investigated how synchronous/asynchronous
properties of the GPe network were modulated by dopamine. To
this end, we first constructed a single compartment model
of a GPe neuron, and applied phase response analysis to
the model GPe neuron [1], changing conductances of a
persistent sodium channel and an L-type calcium channel,
both of which are modulated by dopamine in the striatal
spiny neurons [2].
Results
We examined two conditions; the condition of an
identical input strength, under which the firing rate of the GPe
neuron changed, and that of an identical firing rate, which
was realized by adjusted input currents. Under both
conditions, as both of the conductances increase (dopamine
level was thought to be depleted), stable phase differences
diminished, i.e., the synchronous activity came to be
stable (Fig. 1). The results showed that the dopaminergic
aSFntiagdbuglerLepuh1nadserdtihfferceonncdeistifoonr ovfaraino uidsecnotimcablinpaetriioonds of gNaP
Stable phase differences for various combinations of gNaP
and gL under the condition of an identical period. When both
gNaP and gL took large values, phase difference of 0, i.e., the
synchronous state, was stable.
effect on intrinsic membrane property was one of the
candidates to induce pathological burst activity in the STN.
Kuramoto Y : Chemical oscillations, waves, and turbulence NewYork: Springer-Verlag; 1984 .
Surmeier DJ , Ding J , Day M , Wang Z , Shen W : D1 and D2 dopamine-receptor modulation of striatal glutamatergic signaling in striatal medium spiny neurons . TRENDS in Neurosciences 2007 , 30 : 228 - 234 . (...truncated)