You can find out more about NPF's National Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration.

Francis Crick, one of the most famous scientists of our generation, described a double helix structure that is now known to characterize human DNA (this discovery was published in 1953 along with his colleague James Watson).  Later, in the 1970s, Crick discussed a wish-list for future discoveries, including the use of light to control human cells.  Light science and light therapy have since been considered both “crazy and far-fetched”; however, recent discoveries in the early 21st century have dramatically changed this point of view.  Thanks to some very clever scientists, a new field called optogenetics was born.

What is optogenetics?  The “opto-“ refers to placing light onto the brain to activate channels and/or enzymes that will ultimately change brain cell firing.  The technique is specific, and has the potential to add or delete firing patterns from the brain’s native cells.  Additionally, brain cell firing can be manipulated at precise millisecond intervals.  The fiber-optic light source can be mounted on the skull, or placed deep within the brain.  The genetics part of optogenetics utilizes simple virus carrier systems to deliver genes to the brain.  The most important of these genetic deliveries has been opsin.  Opsin is one of the structures potentially turned on by the light.  The most important known opsin used for this technology is Channelrhodopsin-2, and it was derived by scientists from algae-based systems. By shining light onto the inserted genetic alteration (opsin), scientists can probe the brain’s inner conversations (firing of cells).  The technique has allowed investigators to move past the classical genetic manipulation, which has much less specificity.

Last week Kravitz and colleagues (from the pioneering optogenetics group at Stanford) published an important paper in Nature.  They were able to demonstrate that optogenetics could either worsen or alternatively improve an animal model of Parkinsonism.  The investigators performed a simple experiment where they manipulated the well-established basal ganglia direct and indirect pathways, which are the best known suspects implicated in the genesis of Parkinson’s disease.  The authors reported “optogenetic control of direct- and indirect-pathway medium spiny projection neurons (MSNs), achieved through a viral expression of channelrhodopsin-2 in mice with regulatory elements for the dopamine D1 or D2 receptor. Excitation of the indirect-pathway MSNs elicited a parkinsonian state, distinguished by increased freezing, bradykinesia and decreased locomotor initiations. Activation of direct-pathway MSNs reduced freezing and increased locomotion (Kravitz, 2010).” A month prior to this Nature paper, Bass and colleagues from Wake Forest, described an optogenetic approach to controlling dopamine release (Bass, 2010).

Activating brain circuits by using both light and genetics has thus evolved from a science fiction dream into a true reality.  The technique will likely be refined over the next decade and it will have tremendous potential to unlock important clues underlying the disease processes ultimately responsible for Parkinson’s disease.  Optogenetics may also open up novel therapeutic possibilities.  We can thus conclude there is a bright future ahead for optogenetics, and there is much hope that this technology will help us shine a light on this common, and often disabling human neurodegenerative condition.

Selected References:
We refer the reader to both of these excellent references which describe optogenetics and also detail recent advances in the Parkinson’s disease research arena.

Kravitz AV, Freeze BS, Parker PR, Kay K, Thwin MT, Deisseroth K, Kreitzer AC.
Regulation of parkinsonian motor behaviours by optogenetic control of basal ganglia circuitry. Nature. 2010 Jul 29;466(7306):622-6.

Bass CE, Grinevich VP, Vance ZB, Sullivan RP, Bonin KD, Budygin EA. Optogenetic control of striatal dopamine release in rats.
J Neurochem. 2010 Jun 8.

Posted: 8/3/2010 6:12:27 AM by Cathy Whitlock


Browse current and archived What's Hot in PD? articles, the National Parkinson Foundation's monthly blog for people with Parkinson's written by our National Medical Director, Dr. Michael S. Okun. 

June 2014
Is light therapy a potential treatment modality in Parkinson’s disease?

May 2014
How does the most common genetic cause of Parkinson’s Disease (LRRK2) cause Parkinson’s disease and could it be used to help develop a better therapy?

April 2014
An Update on DAT Scanning for Parkinson’s Disease Diagnosis

March 2014
Could Northera (Droxidopa) Be an Alternative Treatment for Low Blood Pressure and Passing Out Symptoms?

February 2014
The Dream of a Pill Free Existence and the Continuous Dopaminergic Pump for the Treatment of Parkinson's Disease

January 2014
Should I take Inosine to Raise my Uric Acid Levels and Treat my Parkinson’s Disease?

December 2013
Could Fungus and Mold be an Important Contributor to Parkinson’s Disease?

November 2013
Pimavanserin and the Hope for a Better Drug for Hallucinations and Psychosis in Parkinson’s Disease

October 2013
Halting of the Creatine Study

September 2013
The Importance of Identifying and Treating Caregiver Strain

August 2013
Putting Parkinson’s Disease Information into the Palm of Your Hand: Parkinson’s Enters the Smartphon

July 2013
What Parkinson’s Disease Patients Need to Know about H. Pylori Gastrointestinal Infections

June 2013
A2A Receptor Antagonists and Parkinson’s Disease Treatment

May 2013
Another Setback for Trophic Factor Treatment in Parkinson's Disease

April 2013
IPX066 and What Patients Really Want in New Carbidopa/Levodopa (Sinemet) Formulations

March 2013
The Weather Forecast for Parkinson’s Disease Calls for Worldwide Economic Storm

February 2013
Defeating the Barriers to Implementing Exercise Regimens in Parkinson’s Disease Patients

January 2013
When should you start medication therapy for Parkinson’s disease?

December 2012
Neurologist Care Reduces Hospitalizations in Parkinson's Disease

November 2012
A Victory in Court for Parkinson's Disease Patients who Require Ongoing Rehabilitative Therapies

October 2012
Given the recent FDA announcement about Mirapex (pramipexole), should I be worried about dopamine agonists?

September 2012
What about the new Parkinson’s Disease Vaccine? What should I know?

August 2012
Caffeine as a Potential Treatment for Parkinson’s Disease

July 2012
Time to Consider GPi DBS for Parkinson’s Disease: A Shift in the Practice of Patient Selection for DBS

June 2012
A New Treatment for Parkinson’s Disease-Related Constipation

May 2012
Too Many Pills: Improving Delivery Systems for Parkinson’s Disease Drugs

April 2012
Measuring Quality and Assessing Depression in Parkinson's Disease

March 2012
Watch out for Unexpected Obstacles if You Use a Cueing Strategy to Break Freezing of Gait in Parkinson’s Disease

February 2012
Pill Color, Generic Medications and Insurance Issues: Important Medication-Related Tips for the Parkinson’s Disease Patient

January 2012
Are Blood Tests for Parkinson’s Disease on the Horizon?

December 2011
Placing Stem Cells in Animal Models of Parkinson’s Disease: Another Important Step

November 2011
Important News for the Parkinson’s Disease Community: More Evidence that Sinemet and Madopar are Not Toxic and do Not Accelerate Disease Progression

October 2011
The Case for All Parkinson’s Disease Patients to be Co-managed by a Primary Care-Neurologist Team

September 2011
Scientists say Research on Brain Proteins Involved in Parkinson’s Disease is “Shaping” Up

August 2011
Who Actually Takes Care of Most of the Parkinson’s Patients Worldwide: The Need for Education and the Parkinson’s Toolkit

July 2011
If you are Dizzy or Passing Out, it could be Your Parkinson’s Disease or Parkinson’s Disease Medications

June 2011
How Will Group Visits for Parkinson’s Disease Fit into the Future of Parkinson’s Disease Care?

May 2011
Why Patients Should be Wary of Chelation Therapy for Parkinson’s Disease

April 2011
Opening the Door to Gene Therapy in Parkinson’s Disease: The Need for Refinement of the Technology and Approach

March 2011
Does it Matter if I Can’t Get Brand Sinemet?

February 2011
Should I get a DaTscan or PET scan to confirm my diagnosis of Parkinson’s disease?

January 2011
A Critical Reappraisal of the Worst Drugs in Parkinson’s Disease

December 2010
Environmental Risks for PD: Manganese, Welding, Mining, and Parkinsonism

November 2010
Calling for the FDA to Revise the Eight Sinemet a Day Rule

October 2010
Dry Cleaning Solvents and Potential Environmental Risks for Developing Parkinson’s Disease

September 2010
Maintaining the Balance: Why Parkinson’s Disease Patients Need to Understand Drug Recalls, Withdrawals, and Safety Alerts

August 2010
Shining a Light on Parkinson’s Disease: Optogenetics Has a Bright Future in Research

July 2010
Poor Medication Management of Parkinson's Disease During Hospital Admissions: Patients and Families Can Improve Their Hospital-Based Management

June 2010
Why Are Patches and Continuous Release Technology a Big Deal to Parkinson's?

May 2010
Is the PD SURG Trial Another Surge Forward for DBS Therapy?

April 2010
Cycling in PD in Those Who Can’t Walk: Is it Possible?

March 2010
New iPS Stem Cells for PD: What Does it Mean?

February 2010
Time for Comprehensive Care Networks for PD

January 2010
Is Parkinson's Disease a Prion Disease?

December 2009
Parkinson's Disease Linked to Gaucher's Disease

November 2009
Brain Cells Keep Time Stamps: Implications for Parkinson's Disease Therapies

October 2009
Is it Safe to Have an MRI with a DBS in Place?

September 2009
Take Care of Your Bones as They Are Affected in Parkinson's Disease (Even in Men)

August 2009
Is it Time to Start Paying Attention to Pain Symptoms in Parkinson's Disease Patients?

July 2009
Glutathione Fails to Demonstrate Significant Improvement in PD Symptoms

June 2009
Keeping an Eye on Trials Important to the Parkinson's Disease Patient

May 2009
Increased Risk of Melanoma in Parkinson's Disease

April 2009
Finally a DBS Expert Consensus Statement Aimed at Their True Customers: The Patients

March 2009
Pesticides and Environmental Exposure in Parkinson's disease: Should We Stay Away From the Stink Truck?

February 2009
Is Exercise Effective Treatment and Protection Against PD?

January 2009
Why are Transplant Trials Struggling to Succeed in the Treatment of PD?

December 2008
Are Monoamine Oxidase Inhibitors Disease Modifying or Neuroprotective in PD?

November 2008
Update on Gene Therapy for Parkinson's Disease

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Each month, we will feature a new column by NPF's National Medical Director, Dr. Michael Okun, on the latest developments in Parkinson's disease research. Read the latest "What's Hot in PD?" below.

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