Chip inspired by optogenetics uses light to create and modify memories
Drawing inspiration from optogenetics, which uses light to manipulate neurons so that they can be turned on or off, a team of researchers from the Functional Materials and Microsystems Research Group at RMIT University (Melbourne, Australia) has developed a chip that replicates the way the brain stores and loses information.
The new chip is based on an ultrathin material called black phosphorus that changes electrical resistance in response to different wavelengths of light, enabling it to mimic the way that neurons work to store and delete information in the brain.
Research team leader Sumeet Walia says the technology moves us closer towards artificial intelligence (AI) that can harness the brain's full sophisticated functionality. "Being able to store, delete, and process information is critical for computing, and the brain does this extremely efficiently," Walia explains. "We're able to simulate the brain's neural approach simply by shining different colors onto our chip. This technology takes us further on the path towards fast, efficient, and secure light-based computing. It also brings us an important step closer to the realization of a bionic brain—a brain-on-a-chip that can learn from its environment just like humans do."
Taimur Ahmed, lead author of the paper that describes the work, says that being able to replicate neural behavior on an artificial chip offered exciting avenues for research across sectors. "This technology creates tremendous opportunities for researchers to better understand the brain and how it's affected by disorders that disrupt neural connections, like Alzheimer's disease and dementia," Ahmed says.
Related: Optogenetics recovers memories lost to mice with Alzheimer's disease
Developed at RMIT's MicroNano Research Facility, the technology is compatible with existing electronics and has also been demonstrated on a flexible platform for integration into wearable electronics.
Neural connections happen in the brain through electrical impulses. When tiny energy spikes reach a certain threshold of voltage, the neurons bind together to then begin creating a memory.
The chip works by using light to generate a photocurrent. Switching between colors causes the current to reverse direction from positive to negative. This direction switch, or polarity shift, is equivalent to the binding and breaking of neural connections, a mechanism that enables neurons to connect (and induce learning) or inhibit (and induce forgetting). This is akin to optogenetics, where light-induced modification of neurons causes them to either turn on or off, enabling or inhibiting connections to the next neuron in the chain.
To develop the technology, the researchers used black phosphorus that can be inherently defective in nature. This is usually a problem for optoelectronics, but with precision engineering the researchers were able to harness the defects to create new functionality.
The researchers have also demonstrated that the chip can perform logic operations.
Full details of the work appear in the journal Advanced Functional Materials.
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