Researchers at Tsinghua University and collaborators placed a flexible, lantern‑shaped electrode inside the lateral ventricle and recorded stable deep‑brain signals for months, then used those signals to predict memory‑guided choices with up to 98% accuracy in rats, the team reports in National Science Review.
The device, called a lateral ventricular BCI (LV‑BCI), is delivered folded through a pathway similar to routine external ventricular drainage. Once inside the ventricle the electrode expands to conform to the ependymal lining and maintain gentle contact without penetrating brain tissue.
In head‑to‑head tests the LV‑BCI produced a maximum effective bandwidth comparable to subdural electrocorticography (ECoG). Unlike cortical implants, ventricular recordings kept a high signal‑to‑noise ratio through at least 112 days, and spectral signals remained clear for up to 168 days (six months) in the study.
Immunohistochemistry showed only a transient microglial response after implantation that returned to baseline within weeks. By contrast, the authors report persistent microglial activation around cortical electrodes. The team links the ventricular cerebrospinal fluid environment and the electrode’s flexibility to reduced chronic tissue irritation.
To test cognitive decoding, the researchers recorded microstate sequences before rats moved in a memory‑guided T‑maze. A classifier trained on ventricular signals predicted left versus right turns with accuracies as high as 98%, markedly outperforming signals from surface cortical electrodes. The paper notes the LV‑BCI’s proximity to structures such as the hippocampus as a likely source of the deeper decision‑related information.
The authors say future work will address human scaling, imaging compatibility, cerebrospinal fluid dynamics and long‑term safety. The study is open access; the paper is available at https://doi.org/10.1093/nsr/nwag081.
The results establish the lateral ventricle as a viable recording route in animals and point to a ventricular access strategy that may avoid the chronic scarring that limits many current implantable BCIs.
Photo credit: neurosciencenews.com
Tags: BCI, ventricular electrode, ECoG, hippocampus, neural decoding
Topics: Brain–computer interfaces, Neuroprosthetics & neural implants, Neuroscience & neuroplasticity