Mechanisms of gamma oscillations in cortical networks: from emergence to functional role in perception and cognition


Funding: project code PN-II-RU-TE-2014-4-0406/2015, contract 169/1.10.2015 from the State Budget of Romania: National Program II for Research, Development and Innovation, subprogram Human Resources, administered by the Ministry for Education, Research and Youth through the Executive Unit for Funding Research Development and Inovation (UEFISCDI).

Abstract

Fast oscillations (20-80 Hz) are a hallmark of brain activity, correlating with sensory and cognitive processing in normal brain function and being disrupted in brain disorders, such as schizophrenia and autism. Their functional role is poorly understood because the emergence mechanisms are not fully known. Mechanisms such as ING (InterNeuronal Gamma) and PING (Pyramidal-InterNeuronal Gamma) can explain only partly the properties of in vivo gamma oscillations. In a recent study we found that, in contrast to ING and PING, membrane resonance expressed in interneurons could greatly contribute to robust and stable gamma oscillations, via a new mechanism that we called RING (Resonance INduced Gamma). Here, we intend to investigate the presence of this mechanism in vivo, in the visual cortex of rodents. We will carry out multi-electrode recordings, paired with optogenetic stimulation, intracellular recording, and concomitant activation of cholinergic pathways to understand: i) how gamma oscillations emerge in local cortical circuits; ii) if resonance is expressed in interneurons and how this affects circuit-level gamma oscillations; iii) if neuromodulation controls oscillatory activity by modulating the membrane resonance of individual interneurons. Advancing knowledge on mechanisms of fast oscillations will lead to a dramatic progress in grasping their functional role in perception and cognition, and may provide leverage on debilitating brain disorders.


Research team

Dr. Eng. Raul C. Muresan, principal investigator.

[Personal homepage]    [Curriculum Vitae]
Dr. Eng. Vlad V. Moca, postdoc researcher.

[Curriculum Vitae]
Adriana Dăbâcan, PhD researcher.

[Curriculum Vitae]
Medorian Gheorghiu, PhD researcher.

[Curriculum Vitae]


Expected results

The project addresses the emergence mechanisms and properties of gamma oscillations in the cortical circuits of the visual system. We expect that the project will provide the basis for breakthroughs along several directions:

  • Evidencing previously unknown properties of visually-induced gamma oscillations.

  • Finding direct and indirect evidence for linking membrane resonance to circuit-level oscillations. In particular we hope to be able to distinguish between ING, PING and the RING mechanisms or even identify new, previously unknown mechanisms of gamma oscillations.

  • Understanding better the link between neuromodulatory pathways and expression of gamma oscillations, especially related to cholinergic modulation associated with arousal.

  • Development of novel tools to enable proper characterization of oscillatory phenomena in brain activity.



Scientific reports

  • Cumulative scientific report 2015-2016.
     [pdf]



Publications

Articles:

  • Dabacan A. and Muresan R.C. (2016), Robust analysis of non-stationary cortical responses: tracing variable frequency gamma oscillations and separating multiple component input modulations. Proceedings of MediTech 2016, in press.
     [pdf]

  • Dabacan A., Rusu C., Muresan R.C. (2016), Probing Frequency Response in Neural Networks Using Light. Novice Insights, in press.
     [pdf]

Abstracts, extended abstracts, posters and invited talks:

  • Dabacan A. and Muresan R.C. (2016), Effects of periodic stimulation on cortical circuits as a function of stimulated population properties. Society for Neuroscience Annual Meeting, 12-16 November, San Diego, USA. Accepted poster.