Mapping whole brain effects of infrared neural stimulation with positron emission tomography

Abstract

The combination of neuroimaging and targeted neuromodulation is a crucial tool to gain a deeper understanding of neural networks at a circuit level. Infrared neurostimulation (INS) is a promising optical modality that allows to evoke neuronal activity with high spatial resolution without need for the introduction of exogenous substances in the brain. Here, we report the use of whole-brain functional [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) imaging during INS in the dorsal striatum, performed using a multifunctional soft neural probe. We demonstrate the possibility to identify multi-circuit connection patterns in both cortical and subcortical brain regions within a single scan. By using a bolus plus infusion FDG-PET scanning protocol, we were able to observe the metabolic rate evolution in these regions during the experiments and correlate its variation with the onset of the INS stimulus. Due to the focality of INS and the large amount of viable molecular targets for PET, this novel approach to simultaneous imaging and stimulation is highly versatile. This pilot study can pave the way to further understand the brain connectivity on a global scale.

Infrared neural stimulation and electrophysiology in a soft fiber-based neural interface

“…Commercially available rods of fluorinated ethylene-propylene (FEP) copolymer and polysulfone (PSU) were used as starting materials for the preform, [17][18][19] which was heated and pulled at a speed of 2 meters/minute to obtain a final fiber diameter of ∼ 400 μm (Figure 1a). Prior to the fiber fabrication, the viscosity-temperature profiles and refractive indices of both materials had been measured using a rotational rheometer (TA, Discovery Hybrid HR2) and ellipsometer (J.…”

In vivomulti-site electrophysiology enabled by flexible optrodes towards bi-directional spinal cord interrogation

“…Multimodal soft and flexible neural probes have been demonstrated as a powerful tool for distinguishing the causal roles of neural regions in the brain by simultaneously stimulating selected regions and recording their neural response [1,2]. The ability to combine advanced functional materials in a fiber form has enabled the development of novel photonic devices [3][4][5] as well as neural interfaces integrating several functionalities such as stimulation, recording, drug delivery, sensing and imaging [6][7][8][9][10][11]. In particular, the combination of optical stimulation with optogenetics, which exploits light-sensitive ionic membrane channel proteins (opsins), and electrical recording with electrophysiology, which is used to probe and record the local electrical neural response, constitutes an important tool towards the investigation of brain activity [12].…”

Drug delivery and optical neuromodulation using a structured polymer optical fiber with ultra-high NA

“…To achieve an expanded illuminated area in optical neural stimulation, here, we proposed two kinds of UHNA POFs with a thermal drawing fabrication method. Since we used FEP (one of the softest thermoplastics 12,17,18 ) as the cladding material, the flexibility of the proposed probe can be 100-fold higher than that of commercial silica fibers. The integrated MCs can be used for accurate drug delivery.…”