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The role of intra-striatal synaptic interactions for shaping cortico-striatal network dynamics


Jovana Belić (Royal Institute of Technology (KTH), Stockholm and Bernstein Center Freiburg), Andreas Klaus (Karolinska Institutet (KI), Stockholm and National Institute of Mental Health (NIH), Bethesda, USA), Dietmar Plenz (National Institute of Mental Health (NIH), Bethesda, USA), Jeanette Hellgren Kotaleski (Royal Institute of Technology (KTH), Stockholm and Karolinska Institutet (KI), Stockholm )

The basal ganglia consist of several interconnected subcortical nuclei that are supposedly involved in many motor and cognitive functions. The striatum, the input stage of the basal ganglia, is a major recipient of massive glutamatergic inputs from the cerebral cortex and thalamus. Medium spiny neurons (MSNs) dominate in the striatum (up to 95% in rodents). They are inhibitory (GABAergic) and have membrane properties that give them a high threshold for activation [1]. MSNs interact with each other through weak recurrent inhibitory synapses and with low connection probability [2]. Fast-spiking GABAergic interneurons (FSNs) can delay or prevent the emission of an action potential in MSNs [3]. FSNs receive convergent inputs from a wider range of distinct cortical regions compared to nearby MSNs, and despite the fact that they are relatively sparse elements (1-2%) it seems that they have very prominent role in shaping the output of the striatum [4].

Neuronal avalanches are a type of spontaneous activity first observed in vitro by recording local field potentials in cortical neural networks using slices of rat cortex as well as cultured networks [5]. Propagation of spontaneous activity is balanced and shows a branching parameter close to 1. In addition, the number of electrodes driven over threshold during activity is distributed approximately like a power law with an exponent of -3/2 for event sizes suggesting a critical dynamics [5]. Neural avalanches have been shown to provide: optimal information transmission [5, 6], maximal information capacity [6] and maximal dynamic range [7].

We are studying simultaneously striatal and cortical activity in vitro. Preliminary results show that neuronal avalanches in cortex induce activity clusters in striatum whose size distribution can be approximated by a steeper power law than observed in cortex. Based on this we have developed network models in order to determine the impact of different striatal neurons on the more negative exponent. In particular, we are investigating whether FS or MS neurons have any roles in shaping the striatal dynamics.


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2. Tunstall MJ, Oorschot DE, Kean A, Wickens JR: Inhibitory Interactions Between Spiny Projection Neurons in the Rat Striatum. Journal of Neurophysiology 2002, 88: 1263–1269.
3. Tepper J, Koos T, Wilson C. GABAergic microcircuits in the neostriatum. Trends in Neuroscience 2004. 27:662–669.
4. Berke J: Functional properties of striatal fast-spiking interneurons. Frontiers in Systems Neuroscience 2011, 5:1-7.
5. Beggs J, Plenz D: Neural avalanches in neocortical circuits. The Journal of Neuroscience 2003, 23:11167-11177.
6. Shew W, Yang H, Yu S, Roy R, Plenz D: Information capacity and transmission are maximized in
balanced cortical networks with neuronal avalanches. The Journal of Neuroscience 2011, 31:55-63.
7. Shew W, Yang H, Petermann T, Roy R, Plenz D: Neural avalanches imply maximum dynamic range in cortical networks at criticality. The Journal of Neuroscience 2009, 29:15595-15600.
Preferred presentation format: Poster
Topic: Computational neuroscience