New optical neuron chip technology reveals unexpected dopamine dynamics

DGIST Department of Brain Sciences Professor (President Lee Kunwoo) Lee Kwang and his team discovered a new correlation between neural signaling in the brain and dopamine signaling in the striatum. The human brain requires fast neural signal processing in a short period of less than a second. Dopamine is known to have the strongest effect on the brain’s neural signals, but the research team’s new “optical neural chip-based multi-signal brain monitoring technology” shows that changes in dopamine signals within the normal range do not affect processing of the brain’s neural signal.

Dopamine is a chemical neuromodulator that plays an essential role in learning, movement, motivation and decision making. It has been linked to a number of diseases, including Parkinson’s disease, addiction and depression. To analyze the relevance of dopamine signaling to brain neural signal processing and related diseases, DGIST Prof. Lee Kwang and his team developed an “optical neural chip-based multi-brain signal monitoring technology” with Prof. Masmanidis’ team at UCLA. The technology can simultaneously record the brain’s electrical and chemical neural signals and confirmed that dopamine signaling in the artificially manipulated striatum causes action potentials^[1] changes in neurons. The findings were validated through machine learning.

The team used optogenetics to simultaneously observe dopamine and neural activity in the “ventral striatum” while controlling the activity of dopamine neurons. First, when dopamine was not released during neural signal processing in the brain, no abnormalities in neuronal activity were found, and when dopamine was released within the normal physiological range (e.g., during food intake), only small or inconsistent changes in the activity of the neurons was observed. However, when dopamine was artificially released at more than five times the normal physiological range, a significant effect on neural signal processing in the brain was observed. This suggests that other factors may be more important than dopamine signaling in the brain for some neural signaling processes, contrary to current theories.

This study demonstrates for the first time that dopamine signals from food rewards play a secondary role in the rapid modulation of neural activity in the striatum. This suggests that on a secondary time scale, neural activity in the striatum may be influenced by other extrinsic neural inputs rather than dopamine. We will conduct follow-up studies to elucidate the complex physiology of dopamine over time, including its long-term contribution.”

Lee Kuang, Professor, DGIST

The findings were published online at Nature Neuroscience on July.