New Techniques for Investigating Brain Rhythms: Optical Neural Control and Multielectrode Recording

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Boyden, E. S., Han, X., Talei Franzesi, G., Chan, S., Bernstein, J., Qian, X., Li, M. (2009) "New Techniques for Investigating Brain Rhythms: Optical Neural Control and Multielectrode Recording," In: Rhythms of the Neocortex: Where Do They Come From and What Are They Good For? (Kopell N., ed.) pp. 65-75. Washington, DC: Society for Neuroscience.

Progress in neuroscience commonly emerges from technological innovation. It can empower neuroscientists to answer old, much debated questions in a more conclusive fashion and often opens up the possibility of confronting entirely new questions about the brain. To understand how neural dynamics emerge from the action of coordinated ensembles of specific types of neurons in the brain, two core abilities are ever in need of innovation:

• The ability to perturb neural circuit elements in a temporally and spatially precise fashion throughout neural circuits in vivo; and
• The ability to record large ensembles of neurons in the brain of the awake behaving animal.

Rhythmic, synchronous neural activity within and between brain regions has been observed during, or associated with, many brain functions; these include timing-dependent plasticity, global stimulus feature processing, visuomotor integration, emotion, working memory, motor planning, and attention. These activities have been measured with multielectrode recording, electroencephalography (EEG), magnetoencephalography (MEG), and local field potential (LFP) analysis. Furthermore, abnormal patterns of neural synchrony have been associated with a variety of neurological and psychiatric disorders, such as Parkinson’s disease, epilepsy, autism, and schizophrenia. Computationally, synchrony has been implicated in processes such as grouping neurons into cell assemblies that can more effectively represent information to downstream neural networks, acting as a clock for gating or multiplexing information, coordinating information flow within small neural networks, selecting stimuli for attention, and performing pattern recognition.

However, defining the causal role such synchronous patterns play in mediating neural computation and behavior has remained difficult. In recent years, we and others have developed novel technologies that support this agenda and are now finding wide use in neuroscience. In this chapter, we will focus on exploring the implications for neural rhythm analysis of two sets of technologies:

• Genetically encoded molecular sensitizers that enable neurons to be activated or silenced with light in a temporally and spatially precise fashion; and
• Hardware for perturbation and recording of neurons in complex (e.g., three-dimensional) geometries throughout the brain.