Researchers at the Center for Nanomedicine within the Institute for Basic Science (IBS) and Yonsei University in South Korea have unveiled a groundbreaking technology that can manipulate specific regions of the brain using magnetic fields, potentially unlocking the secrets of high-level brain functions such as cognition, emotion, and motivation. The team has developed the world’s first Nano-MIND (Magnetogenetic Interface for NeuroDynamics) technology, which allows for wireless, remote, and precise modulation of specific deep brain neural circuits using magnetism.

The human brain contains over 100 billion neurons interconnected in a complex network. Controlling the neural circuits is crucial for understanding higher brain functions like cognition, emotion, and social behavior, as well as identifying the causes of various brain disorders. Novel technology to control brain functions also has implications for advancing brain-computer interfaces (BCIs), such as those being developed by Neuralink, which aim to enable control of external devices through thought alone.

While magnetic fields have long been used in medical imaging due to their safety and ability to penetrate biological tissue, precisely controlling brain circuits with magnetic fields has been a significant challenge for scientists.

Researchers at the IBS have successfully developed a cutting-edge magnetogenetics technology called Nano-MIND, which enables wireless and remote control of specific brain regions to modulate complex brain functions such as emotions, social behaviors, and motivation in animals. This advanced technology leverages magnetic fields and magnetized nanoparticles to selectively activate targeted brain circuits. The key innovation lies in the selective expression of nano-magnetoreceptors in specific neuronal types and brain circuits and activating them with rotating magnetic fields at precise moments, allowing for spatiotemporal control of neural activity.

First, the Nano-MIND technology demonstrated its capability by selectively activating inhibitory GABA receptors in the medial preoptic area (MPOA), which is responsible for maternal behaviors. Activation of these neurons in non-maternal female mice significantly increased nurturing behaviors, such as bringing pups to their nest, similar to maternal mice.

Additionally, the technology was used to regulate feeding behaviors by targeting motivation circuits in the lateral hypothalamus. Activation of inhibitory neurons within these areas resulted in a 100% increase in appetite and feeding behaviors in mice. Conversely, activating excitatory neurons led to a more than 50% reduction in appetite and feeding behaviors.

These results show that nano-MIND technology can selectively activate desired brain circuits to bidirectionally modulate higher brain functions, paving the way for advancements in neuroscience and potential therapeutic applications.

Director CHEON Jinwoo of the Center for Nanomedicine stated, "This is the world's first technology to freely control specific brain regions using magnetic fields. We expect it to be widely used in research to understand brain functions, sophisticated artificial neural networks, two-way BCI technologies, and new treatments for neurological disorders."

This study was published in Nature Nanotechnology on July 3, 2023.

Figure 1. Overview of nano-MIND technology - regulation of higher-order brain functions through selective control of specific neurons and brain circuits
Using nano-MIND technology, higher-order brain functions such as emotions, sociability, and survival instincts in animals can be freely regulated through selective control of specific neurons and brain circuits. This enables the discovery of roles and operating principles of various brain circuits, which is essential for brain science research and can be utilized for AI technology advancement through the construction of better artificial neural networks.

Figure 2. Activation of specific neurons and brain circuits through nano-MIND technology
Using nano-MIND technology, higher-order brain functions such as emotions, sociability, and survival instincts in animals can be freely regulated through selective control of specific neurons and brain circuits. This enables the discovery of roles and operating principles of various brain circuits, which is essential for brain science research and can be utilized for AI technology advancement through the construction of better artificial neural networks.
Top) 1. Selective expression of nano-magnetoreceptors only in desired target neurons in a mouse model with applied Cre-loxP genetic engineering technology. 2. When rotational magnetic field stimulation is applied, the nano-magnetoreceptors of the target neurons are activated. 3. The brain circuit involving the target neurons is selectively activated and controlled.
Bottom) Expression of nano-magnetoreceptors in the lateral hypothalamus and activation of target neurons. Nano-magnetoreceptors (green) are selectively expressed only in target neurons (red) and their activity increases in response to magnetic field signals.

Figure 3. Experiment on regulating brain circuits responsible for sociability and emotions using nano-MIND
1. Nano-magnetoreceptors generated only in inhibitory neurons of the medial preoptic area (MPOA) selectively activate the inhibitory brain circuit of the MPOA in response to magnetic field signals. This enables the regulation of brain circuits responsible for maternal love and parental behavior.
2. When magnetic stimulation is applied, female mice injected with nano-magnetoreceptors show increased maternal behavior and rescue pup mice to their own nest, despite not being mother mice. In contrast, control female mice show no interest in the pup mice.
3. Only in female mice with applied nano-MIND technology, the brain circuit responsible for maternal love is activated by magnetic stimulation, resulting in the rescue of all pup mice and a more than 4-fold increase in care time compared to regular mice.

Figure 4. Bidirectional regulation of motivation control brain circuits using nano-MIND
1. When magnetic stimulation is applied through nano-magnetoreceptors selectively expressed in excitatory or inhibitory neurons of the lateral hypothalamus (LH), bidirectional regulation of brain circuits responsible for motivation and appetite becomes possible.
2. When inhibitory neurons in the LH are selectively activated by nano-MIND, the mouse's appetite and feeding behavior increase twofold. Conversely, when excitatory neurons in the LH are selectively activated by nano-MIND, the mouse's appetite and feeding behavior decrease by more than half.