Plexon

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Founded in 1983 by Harvey Wiggins, Plexon has grown from a one-person company to a team of engineers, biophysicists, and neuroscientists with expertise in research, product development, and advanced neurotechnology research systems. Plexon’s customers include over 400 domestic and international academic research labs, research hospitals, pharmaceutical companies, and military labs. In recognition of the organization’s accomplishments, Plexon was named to the North America Fast 500 and the Texas Crescent Technology Fast 50 by Deloitte & Touche USA LLP in both 2004 and 2005.

perspectivePlexon is a leading provider of “neurotechnology”: innovative data-acquisition systems for recording and analyzing signals recorded from the brain or peripheral nervous system and stimulation systems for applying information back into the brain and nervous system. Plexon’s tools are used for fundamental research into the functioning of the nervous system as well as more applied areas such as brain-machine interfaces and neuroprosthetics.

The Challenge

Traditional brain electro-physiology, recording signals coming from the brain, is fairly straightforward and is done by placing electrodes in the brain to monitor electrical impulses traveling down the nerves. Conversely, putting information into the brain or nervous system is much harder. Current can be injected into the brain, but it is difficult to control where the current goes and often large groups of neurons are affected.

A “hot” trend in neuroscience is the emerging field of optogenetics. This advanced technique gives researchers unprecedented control and allows them to specifically activate or inhibit subgroups of neurons within the brain. Optogenetics involves genetically modifying nerve cells to make them light sensitive. By shining the right wavelength of light on these light sensitive cells, researchers can effectively turn them on or off.

“Just like with electrical stimulation, light stimulation tends to illuminate large areas of brain tissue. Fortunately, the molecular biology component of optogenetics is highly specific and allows the researchers to make only very specific subgroups of cells respond to the light.”

Initially, optogenetic research was done using lasers as the light source. But the lasers used were expensive, had unstable output levels, and had relatively short lifetimes.

Top View of the Internal Stack.

Top View of the Internal Stack.

The Solution

Plexon wanted to expand the accessibility of optogenetic tools to more brain and nervous system researchers and replace lasers with a less expensive and more stable research instrument. They determined that using LEDs instead of lasers to generate light could provide much lower cost, longer lasting, and more stable solutions. Plexon needed to design a high power computer controlled current source for driving the LEDs.

Plexon developed the Optogenetic Controller, leveraging two custom boards created by the Plexon team, with an Opal Kelly XEM6001 module with USB interface in the middle. The product is essentially “a fancy LED driver.” It includes four channels of programmable current drivers that can deliver in excess of 1.1 A each for driving high-powered LEDs. The high-powered LEDs in turn generate the light to do the optogenetic research.

Side View of the Internal PCB Stackup.

Side View of the Internal PCB Stackup.

The Results

“We knew, based on our previous experience with the XEM3001, that leveraging the XEM6001 and FrontPanel software from Opal Kelly would improve our time to market for this tool,” said Craig Patten, Director, Hardware & Devices at Plexon. “With the XEM6001, we were able to get a more powerful FPGA and at the same time we were able to essentially reuse a board that we had designed for use with the XEM3001.”

“Another desirable feature of the XEM6001 was its flash memory. We wanted our device to be capable of working in a stand-alone setting, disconnected from a PC. With the flash memory, after initial set up on the computer, the Optogenetic Controller could be disconnected and used by researchers wherever they like.”

“We saved significant time by using the XEM6001 as compared to rolling our own solution. Using the XEM6001 was an attractive way to get up and running quickly. We also leveraged the work we’d done in the past with the XEM3001 and, because of the added functionality in the XEM6001, we were able to do even more. Using Opal Kelly saved us months in our development efforts.”