A team of researchers from the Exploratory Research Center on Life and Living Systems (ExCELLS) and the National Institute for Physiological Sciences (NIPS) have developed a groundbreaking method for in vivo brain imaging. This new technique allows for the observation of neuronal structures and activities in awake mice on a large scale and for an extended period of time.

The method, known as the "nanosheet incorporated into light-curable resin" (NIRE) method, involves the use of fluoropolymer nanosheets covered with light-curable resin. By incorporating these materials, the researchers were able to create larger cranial windows, spanning from the parietal cortex to the cerebellum.

Lead author Taiga Takahashi, from the Tokyo University of Science and ExCELLS, highlights the superiority of the NIRE method over previous techniques. The use of biocompatible nanosheets and transparent light-curable resin allows for the creation of larger cranial windows that maintain their transparency for a long time, even in highly curved areas like the cerebellum.

The NIRE method utilizes light-curable resin to fix polyethylene-oxide-coated CYTOP (PEO-CYTOP) nanosheets onto the brain surface, creating a tight-fitting "window." This window enables researchers to observe multiple brain regions in living mice, providing high-resolution imaging with sub-micrometer accuracy.

Importantly, the NIRE method has the potential for long-term observation, lasting over six months, without significantly impacting transparency. This prolonged imaging capability opens up possibilities for studying neuroplasticity at various levels, from networks to individual cells, as well as during maturation, learning, and neurodegeneration.

Tomomi Nemoto, corresponding author from ExCELLS and NIPS, emphasizes that the NIRE method represents a significant advancement in the field of neuroimaging. Its ability to create large cranial windows with prolonged transparency and minimal motion artifacts allows for large-scale, long-term, and multi-scale in vivo brain imaging.

Researchers believe that this novel method will unlock new insights into neural processes associated with growth, development, learning, and neurological disorders. Areas of exploration include neural population coding, neural circuit remodeling, and higher-order brain functions that rely on coordinated activity across different regions.

In conclusion, the NIRE method revolutionizes brain imaging by providing a platform for studying neuroplastic changes over extended periods in awake mice engaged in various behaviors. This breakthrough opens doors to unraveling the complexities of the brain and enhancing our understanding of its function.

The study, titled "Large-scale cranial window for in vivo mouse brain imaging utilizing fluoropolymer nanosheet and light-curable resin," was published in Communications Biology in 2024.