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A cortical microcircuit model to study structure-activity - - PowerPoint PPT Presentation

A cortical microcircuit model to study structure-activity relationships Rodrigo Felipe de Oliveira Pena Prof. Dr. Antnio C. Roque University of So Paulo - USP Ribeiro Preto Rodrigo F. O. Pena - rodrigo.pena@usp.br


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A cortical microcircuit model to study structure-activity relationships

Rodrigo Felipe de Oliveira Pena

  • Prof. Dr. Antônio C. Roque

Laboratory of Neural Systems (SisNe) - sisne.org_ Rodrigo F. O. Pena - rodrigo.pena@usp.br

University of São Paulo - USP Ribeirão Preto

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Cortical connectivity

Vertical view 6 layers (I - VI)

Specific electrophysiological patterns

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Neuronal variability

(a) RS (b) IB (c) CH (d) FS (e) LTS

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Morphology: pyramidal, basket, chandelier, etc

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  • Slow (< 1 Hz) and high amplitude

network oscillations;

  • Neurons with low firing rates
  • Non-Gaussian firing rate distribution

Hromádka et al., PLoS Biology 6:e16, 2008

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Cortical signatures during self-sustained activity (SSA)

Subject is awake but not submitted to sensory of behavioural tasks

SSA

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Maimon and Assad, Neuron 62:426-440, 2009 Haider et al., Nature 493:97-102, 2013

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  • Irregularity
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What has been done recently?

Classification of neuronal spiking patterns Improved knowledge of cortical structure Different hypotheses to explain cortical dynamics

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Motivation Despite growing data sets Relation between

Cortical activity Electrophysiological classes Cortical structure

is poorly understood

It is important to have a model that reproduces all of the structured- activity of the cortex

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Methods

Neurons

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Synapses

Izhikevich model

Izhikevich, E. M. (2003).

Pre Post

Spike EPSP

Exc: gmax = gex Inh: gmax = gin

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Methods

Model

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Integrated connectivity map (Potjans and Diesmann, 2014) Full-scale 1mm² microcircuit connectivity with 80.000 neurons

Only connections with probabilities >0.04 are shown

L2/3 L4 L5 L6 Excitatory Neurons Inhibitory Neurons Excitatory Synapses Inhibitory Synapses

Thalamic input - rate 15Hz

4000 Neurons 768043 Synapses

Background input - rate 8Hz

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Probability

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4000 Neurons - 80% excitatory and 20% inhibitory Divide them proportionally into layers Connect following wiring rule

Spatial location

Cell’s spatial location is determined by it’s layer Assume maximum delay is set to 10ms

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Methods

Building the model

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Methods

Stimuli

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Scenario A Scenario B

in vivo cortico-cortical connections background input v=8Hz (poisson fixed rate) thalamic connections thalamic input v=15Hz (poisson fixed rate) (L4 and L6) deafferentation turn off thalamic input

  • nly background input v=8Hz

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Methods

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Measurements

1. Spike trains, membrane voltages 2. Individual and Mean population frequencies 3. ISI (interspike interval) - Time interval between spikes. 4. CV (coefficient of variation of a neuron’s ISIs) - Ratio of standard deviation to the

  • mean. 


(Gabbiani and Koch, 1998; Dayan and Abbott, 2001; Laing and Lord, 2009)

5. Synchrony - Normalized to be between 0 and 1.

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(Golomb et. al., 2001)

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Results

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Scenario A

Experiment: Parameter search

  • We look for (cortical signatures):

Collective low spiking frequency (< 1 Hz) Irregularity in the individual neuronal spikes Asynchronous activity Large sub-threshold fluctuations Tsimulation = 1000 ms 30 different seeds

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Simulation Parameters

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Results

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Scenario A

Experiment: Parameter search

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Results

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Scenario A

Experiment: Parameter search

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Results

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(gex = 4,gin = 15)

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Results

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Scenario A X Scenario B

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(gex = 4,gin = 15)

Similar to ‘UP' and ‘DOWN' states (two preferable subthreshold states during anesthesia)

Steriade et al., (1993); Sanchez-Vives et al., (2000)

Thalamic input is turned off at 500 ms

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Summary and Conclusions

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Model of local cortical network shows realistic behavior Agreement with experimental recordings The model is being used to study structure-activity relationships NeuroMat members may use the model as a toy model

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References

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Acknowledgements

FAPESP/CEPID/Neuromat (grant 2013/07699-0). FAPESP 2013/25667-8. Using resources of the LCCA-Laboratory of Advanced Scientific Computation of the University of São Paulo.

Binzegger, T., Douglas, R. J., & Martin, K. A. (2004). Brette et al., (2007). Brunel N., (2000). (Dayan and Abbott, 2001) Douglas and Martin, (2004). Gabbiani and Koch, 1998; (Golomb et. al., 2001) Izhikevich, E. M. (2003). Laboratory of Neural Systems (SisNe) - sisne.org_

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Izhikevich, E. M., & Edelman, G. M. (2008). Laing and Lord, 2009 Mountcastle, V. B. (1997). Potjans, T. C., & Diesmann, M. (2014). Sanchez-Vives et al., (2000) Steriade et al., (1993); Wester and Contreras (2012).

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Rodrigo F. O. Pena - rodrigo.pena@usp.br

Thank you very much!

Laboratory of Neural Systems (SisNe) - sisne.org_ Rodrigo F. O. Pena - rodrigo.pena@usp.br