The Latest Articles on Brain Imaging Technologies

Our staff editors continue to share exciting, interesting, and thought-provoking reading material in the recommended articles series.

This week, we would like to share several latest articles on Brain Imaging Technologies.

Title: Brain connectomics: time for a molecular imaging perspective?
Authors: Arianna Sala, Aldana Lizarraga, Silvia Paola Caminiti, Vince D. Calhoun, Simon B. Eickhoff, Christian Habeck, Sharna D. Jamadar, Daniela Perani, Joana B. Pereira, Mattia Veronese, Igor Yakushev
Type: Review
Abstract:
In the past two decades brain connectomics has evolved into a major concept in neuroscience. However, the current perspective on brain connectivity and how it underpins brain function relies mainly on the hemodynamic signal of functional magnetic resonance imaging (MRI). Molecular imaging provides unique information inaccessible to MRI-based and electrophysiological techniques. Thus, positron emission tomography (PET) has been successfully applied to measure neural activity, neurotransmission, and proteinopathies in normal and pathological cognition. Here, we position molecular imaging within the brain connectivity framework from the perspective of timeliness, validity, reproducibility, and resolution. We encourage the neuroscientific community to take an integrative approach whereby MRI-based, electrophysiological techniques, and molecular imaging contribute to our understanding of the brain connectome.
Access this article: https://doi.org/10.1016/j.tics.2022.11.015

Title: Study on brain function of the frontal lobe in patients with functional gastroduodenal disease by near-infrared functional imaging
Authors: Yanhong Hou, Lin Zhang, Xiaofei Chen, Yujing Wang, Tong Jiang, Qinjiazi Qi, Chuanxiao Zhang, Chao Shi
Type: Research Article
Abstract:
Objective
functional gastroduodenal disease is the main type of functional gastrointestinal disease in the clinical department of Gastroenterology and psychosomatic medicine at present, which accounts for a large proportion of outpatients in gastroenterology. The main manifestations are epigastric pain, dyspepsia, belching, chronic nausea, and vomiting. The purpose of this study is to explore the changes in brain function in patients with functional gastroduodenal diseases through experiments to reveal the possible central etiology and development process.

Methods
the functional changes of the prefrontal lobe in patients with functional gastroduodenal diseases and normal controls were detected and analyzed by near-infrared brain imaging. At the same time, SCL-90 was used to evaluate the mental health status of patients with functional gastroduodenal diseases and normal controls. The changes in the autonomic nerve system in patients and normal controls were detected and compared by heart rate variability trend chart.

Results
the activity of left prefrontal lobe areas s8-d8, s10-d4, s10-d10 and s10-d15 in patients with functional gastroduodenal disease was significantly lower than normal controls (p < 0.05). The SCL-90 scale showed that there were significant differences between patients with functional gastroduodenal disease and normal controls, especially in depression, compulsion, anxiety, somatization, interpersonal sensitivity and hostility (p < 0.05). There was no significant difference in lf/hf values detected by the HRV trend chart (p > 0.05).

Conclusion
the function of the left frontal lobe is decreased in patients with functional gastroduodenal disease. The autonomic nervous system may be related to the connection system between the brain center and internal organs.
Access this article: https://doi.org/10.1016/j.biopha.2022.114182

Title: Multiple CEST contrast imaging of nose-to-brain drug delivery using iohexol liposomes at 3T MRI
Authors: Lok Hin Law, Jianpan Huang, Peng Xiao, Yang Liu, Zilin Chen, Joseph H.C. Lai, Xiongqi Han, Gerald W.Y. Cheng, Kai-Hei Tse, Kannie W.Y. Chan
Type: Research Article
Abstract:
Image guided nose-to-brain drug delivery provides a non-invasive way to monitor drug delivered to the brain, and the intranasal administration could increase effective dose via bypassing Blood Brain Barrier (BBB). Here, we investigated the imaging of liposome-based drug delivery to the brain via intranasal administration, in which the liposome could penetrate mucus and could be detected by chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) at 3T field strength. Liposomes were loaded with a computed tomography (CT) contrast agent, iohexol (Ioh-Lipo), which has specific amide protons exchanging at 4.3 ppm of Z-spectrum (or CEST spectrum). Ioh-Lipo generated CEST contrasts of 35.4% at 4.3 ppm, 1.8% at −3.4 ppm and 20.6% at 1.2 ppm in vitro. After intranasal administration, these specific CEST contrasts were observed in both olfactory bulb (OB) and frontal lobe (FL) in the case of 10% polyethylene glycol (PEG) Ioh-Lipo. We observed obvious increases in CEST contrast in OB half an hour after the injection of 10% PEG Ioh-Lipo, with a percentage increase of 62.0% at 4.3 ppm, 10.9% at −3.4 ppm and 25.7% at 1.2 ppm. Interestingly, the CEST map at 4.3 ppm was distinctive from that at −3.4 pm and 1.2 ppm. The highest contrast of 4.3 ppm was at the external plexiform layer (EPL) and the region between left and right OB (LROB), while the CEST contrast at −3.4 ppm had no significant difference among all investigated regions with slightly higher signal in olfactory limbus (OL, between OB and FL) and FL, as validated with histology. While no substantial increase of CEST contrast at 4.3 ppm, −3.4 ppm or 1.2 ppm was observed in OB and FL when 1% PEG Ioh-Lipo was administered. We demonstrated for the first time the feasibility of non-invasively detecting the nose-to-brain delivery of liposomes using CEST MRI. This multiple-contrast approach is necessary to image the specific distribution of iohexol and liposome simultaneously and independently, especially when designing drug carriers for nose-to-brain drug delivery.
Access this article: https://doi.org/10.1016/j.jconrel.2023.01.011

Title: The role of the orbitofrontal cortex in exercise addiction and exercise motivation: A brain imaging study based on multimodal magnetic resonance imaging
Authors: Feifei Zhang, Hongsheng Xie, Song Wang, Fei Li, Qiyong Gong, Zhiyun Jia
Type: Research Article
Abstract:
Background
Excessive exercise may also lead to exercise addiction (EXA), which is harmful to people's physical and mental health. Behavioral and neuroimaging studies have demonstrated that addictive disorders are essentially motivational problems. However, little is known about the neuropsychological mechanism of EXA and the effects of motivation on EXA.

Methods
We investigated 130 regularly exercised participants with EXA symptoms to explore the neurobiological basis of EXA and its association with motivation. The correlation between EXA and gray matter volume (GMV) was evaluated by whole-brain regression analysis based on voxel-based morphometry. Then, regional brain function was extracted and the relationship between brain structure-function-EXA was analyzed. Finally, mediation analysis was performed to further detect the relationship between the brain, motivation, and EXA.

Results
Whole-brain correlation analyses showed that the GMV of the right orbitofrontal cortex (OFC) was negatively correlated with EXA. The function of the right OFC played an indirect role in EXA and affected EXA via the GMV of the OFC. Importantly, the GMV of the right OFC played a mediating role in the relationship between ability motivation and EXA. These results remain significant even when adjusting for sex, age, body mass index, family socioeconomic status, general intelligence, total intracranial volume, and head motion.

Limitation
The results should be interpreted carefully because only the people with EXA symptoms were included.

Conclusion
This study provided evidence for the underlying neuropsychological mechanism of the important role of the right OFC in EXA and revealed that there may be a decrease in executive control function in EXA.
Access this article: https://doi.org/10.1016/j.jad.2023.01.030

Title: Brain Response Induced by Peroneal Electrical Transcutaneous Neuromodulation Invented for Overactive Bladder Treatment, as Detected by Functional Magnetic Resonance Imaging
Authors: Jan Krhut，Jaroslav Tintěra，Michal Rejchrt，Barbora Skugarevska, Michal Grepl, Roman Zachoval, Peter Zvara, Bertil F.M. Blok
Type: Research Article
Abstract:
Objectives
In this study, we aimed to investigate whether peroneal electrical Transcutaneous Neuromodulation invented for overactive bladder (OAB) treatment elicits activation in brain regions involved in neural regulation of the lower urinary tract.

Materials and Methods
Among 22 enrolled healthy female volunteers, 13 were eligible for the final analysis. Functional magnetic resonance imaging (fMRI) (Siemens VIDA 3T; Erlangen, Germany) was used to compare the brain region activation elicited by peroneal electrical Transcutaneous Neuromodulation with the activation elicited by sham stimulation. Each subject underwent brain fMRI recording during eight 30-second periods of rest, alternating with 30-second periods of passive feet movement using the sham device, mimicking the motor response to peroneal nerve stimulation. Subsequently, fMRI recording was performed during the analogic “off-on” stimulation paradigm using peroneal electrical transcutaneous neuromodulation. Magnetic resonance imaging data acquired during both paradigms were compared using individual and group statistics.

Results
During both peroneal electrical Transcutaneous Neuromodulation and sham feet movements, we observed activation of the primary motor cortex and supplementary motor area, corresponding to the cortical projection of lower limb movement. During peroneal electrical Transcutaneous Neuromodulation, we observed significant activations in the brain stem, cerebellum, cingulate gyrus, putamen, operculum, and anterior insula, which were not observed during the sham feet movement.

Conclusions
Our study provides evidence that peroneal electrical Transcutaneous Neuromodulation elicits activation of brain structures that have been previously implicated in the perception of bladder fullness and that play a role in the ability to cope with urinary urgency. Our data suggest that neuromodulation at the level of supraspinal control of the lower urinary tract may contribute to the treatment effect of peroneal electrical Transcutaneous Neuromodulation in patients with OAB.
Access this article: https://doi.org/10.1016/j.neurom.2022.11.016