Combining light restriction and optogenetics to dissect the neural circuitry underlying behavior
- Rohit Prakash.
- Sept. 2012.
- Physical description
- online resource (iii, 184 pages) : illustrations (some color)
- Prakash, Rohit.
- Clandinin, Thomas R. (Thomas Robert), 1970- thesis advisor.
- Deisseroth, Karl thesis advisor (primary).
- Hestrin, Shaul. thesis advisor.
- Malenka, Robert C. thesis advisor.
- Stanford University. Neurosciences Program.
- Stanford University. Committee on Graduate Studies. degree grantor.
- Includes bibliographical references (p. 176-184). 184 refs.
- Aberrant states in the nervous system, both acute and chronic are the cause of mental health diseases that affect more than a quarter of Americans over the age of 18. The mechanisms underlying mental health diseases such as Parkinsons, schizophrenia, anxiety, and depression are poorly understood, and thus current treatment approaches are often ineffective or carry with them significant side effects. In order to improve our understanding of these diseases and others, new tools must be developed that take into account the complex dynamics and diversity of circuit elements that make up the neural substrates from which these behaviors arise from. Our lab has pioneered the use of light activated microbial opsins in mammalian neurons in order that we can manipulate neural circuits with cell- type specificity, millisecond temporal precision, and millimeter spatial resolution -- termed 'Optogenetics' . These genetically encoded elements include two broad classes, excitatory channels such as Channelrhodopsin - 2 (ChR2) and inhibitory pumps such as Halorhodopsin (NpHR). The use of these tools allow for bidirectional control ove r cell types and connections that make up the neural circuits that underlie behavior within normal and diseased mental health states using simple gene and light targeting approaches. But, the nervous system's structural complexity -- both in the geometrical arrangement of neurons and connections between neurons - requires more than these basic approaches to dissect its function. To address this extra layer of complexity, the spatial control of light excitation itself could be a versatile method in combination with optogenetic approaches to dissect neural circuitry. The studies herein look to build upon current optogenetic technology by utilizing light restriction in order to control and dissect neural circuits with high precision. There are two approaches used to accomplish this: (1) in vivo and ex vivo one photon light restriction that utilize simple light restrictive optical elements to more precisely stimulate and inhibit both genetically targeted cells or connections between close brain areas and (2) in vivo and ex vivo two photon techniques that allow for fast excitation, inhibition, and bi- stable modulation at the level of a single - cell, multiple single - cells, or in some cases, sub-cellularly . The tools developed here can be used in a variety of systems and allows for the dissection of neural circuitry using optogenetics to a new level of precision that was otherwise unapproachable via any technique available to researchers. As these tools are further developed, a bridge between the individual cellular contributions to neural circuit function and behavioral neuroscience will hopefully emerge.
- Publication date
- Submitted to the Department of Neurosciences and the Committee on Graduate Studies of Stanford University.
- Thesis (Ph.D.)--Stanford University, 2012.