Their study titled “Network Connectivity Changes Following Long-Term Cocaine Use and Abstinence,” was highlighted by the editor of Journal of Neuroscience in “This Week in The Journal.” The findings show that continued cocaine use affects how crucial neural networks communicate with one another in the brain, including the default mode network (DMN), the salience network (SN), and the lateral cortical network (LCN).

“The disrupted communication between the DMN and SN can make it harder to focus, control impulses, or feel motivated without the drug,” said Li-Ming Hsu, PhD, assistant professor of radiology and lead author on the study. “Essentially, these changes can impact how well they respond to everyday situations, making recovery and resisting cravings more challenging.”

Hsu led this project during his postdoctoral tenure at the Center for Animal MRI in the Biomedical Research Imaging Center and the Department of Neurology. The work provides new insights into the brain processes that underlie cocaine addiction and creates opportunities for the development of therapeutic approaches and the identification of an imaging marker for cocaine use disorders.

The brain operates like an orchestra, where each instrumentalist has a special role crucial for creating a coherent piece of music. Specific parts of the brain need to work together to complete a task. The DMN is active during daydreams and reflections, the SN is crucial for attentiveness, and the CEN, much like a musical conductor, plays a role in our decision-making and problem-solving.

The research was motivated by observations from human functional brain imaging studies suggesting chronic cocaine use alters connectivity within and between the major brain networks. Researchers needed a longitudinal animal model to understand the relationship between brain connectivity and the development of cocaine dependence, as well as changes during abstinence.

Researchers employed a rat model to mimic human addiction patterns, allowing the models to self-dose by nose poke. Paired with advanced neuroimaging techniques, the behavioral approach enables a deeper understanding of the brain’s adaptation to prolonged drug use and highlights how addictive substances can alter the functioning of critical brain networks.

Hsu’s research team used functional MRI scans to explore the changes in brain network dynamics on models that self-administrated cocaine. Over a period of 10 days followed by abstinence, researchers observed significant alterations in network communication, particularly between the DMN and SN.

These changes were more pronounced with increased cocaine intake over the 10 days of self-administration, suggesting a potential target for reducing cocaine cravings and aiding those in recovery. The changes in these networks’ communication could also serve as useful imaging biomarkers for cocaine addiction.

The study also offered novel insights into the anterior insular cortex (AI) and retrosplenial cortex (RSC). The former is responsible for emotional and social processing; whereas, the latter controls episodic memory, navigation, and imagining future events. Researchers noted that there was a difference in coactivity between these two regions before and after cocaine intake. This circuit could be a potential target for modulating associated behavioral changes in cocaine use disorders.

“Prior studies have demonstrated functional connectivity changes with cocaine exposure; however, the detailed longitudinal analysis of specific brain network changes, especially between the anterior insular cortex (AI) and retrosplenial cortex (RSC), before and after cocaine self-administration, and following extended abstinence, provides new insights,” said Hsu.

Scientists from Tohoku University have investigated whether the early atmospheric conditions on Mars had the potential to foster the formation of biomolecules — organic compounds essential for biological processes. Their findings, published in Scientific Reports, offer intriguing insights into the plausibility of Mars harboring life in its distant past.

Today, Mars presents a harsh environment characterized by dryness and extreme cold, but geological evidence hints at a more hospitable past. About 3.8-3.6 billion years ago, the planet probably had a temperate climate, sustained by the warming properties of gases like hydrogen. In such an environment, Mars may have had liquid water, a key ingredient for life as we know it.

The researchers investigated whether formaldehyde could have formed in the early Martian environment. Formaldehyde is a simple organic compound that plays a crucial role as a precursor for the formation of vital biomolecules through purely chemical or physical processes. These biomolecules, like amino acids and sugars, serve as the fundamental building blocks for proteins and RNA, essential components of life.

Using an advanced computer model, the team simulated the potential atmospheric composition of early Mars to explore the potential for formaldehyde production. The model was built with the assumption that the atmosphere was rich in carbon dioxide, hydrogen, and carbon monoxide. Their simulations suggest that the ancient Martian atmosphere could have provided a continuous supply of formaldehyde which would have potentially led to the creation of various organic compounds. This raises the intriguing possibility that the organic materials detected on the Martian surface could have originated from atmospheric sources, particularly during the planet’s two earliest geological periods.

“Our research provides crucial insights into the chemical processes that may have occurred on ancient Mars, offering valuable clues to the possibility of past life on the planet,” says Shungo Koyama, lead author of the study. By revealing that there were conditions favorable for the formation of bio molecules, the research broadens our understanding of the planet’s ancient capacity to sustain life.

Next, the team plans to analyze geological data gathered by NASA’s Martian rovers, with the aim of increasing their understanding of organic materials present early in the planet’s history. By comparing the expected carbon isotopes of ancient formaldehyde with data from Martian samples, they hope to get a better picture of the processes that shaped the planet’s organic chemistry

Traditional industrial production of H₂O₂ via the anthraquinone process using hydrogen and oxygen, is highly energy-intensive. This approach employs toxic solvents and expensive noble-metal catalysts, and generates substantial waste from side reactions. In contrast, photocatalytic production of H₂O₂ from oxygen and water offers an energy-efficient, mild and clean route. Most importantly, it addresses the common drawbacks of existing photocatalytic systems, such as low activity, heavy use of additional alcohol sacrificial donors, and the necessity for pure oxygen gas input.

A research team led by Professor JIANG Donglin from the NUS Department of Chemistry has developed a new type of photocatalyst for the efficient artificial photosynthesis of H₂O₂ from water and air. The researchers constructed hexavalent covalent organic frameworks (COFs) in which the skeleton is designed to be donor-acceptor π columns for high-rate photo-induced charge generation and catalytic active sites. In parallel, the pore is engineered with hydraulically sensitivetrigonal microporous channels for immediate delivery of reactants water and oxygen. As a result, these hexavalent COFs produce H₂O₂ spontaneously and efficiently from water and atmospheric air when exposed to visible light in both batch and flow reactors. Under laboratory conditions, the COFs demonstrate a quantum efficiency of 17.5 per cent under visible light at 420 nm in batch reactors. This system can be developed to construct self-cleaning surfaces and for disinfection treatments.

The research findings were published in the journal Nature Catalysis on 13 February 2024.

Prof Jiang said, “In this work, we successfully addressed a key and common issue in photocatalysts, electrocatalysts and heterogeneous catalysts, which is the efficient supply of charges and mass to catalytic sites. Our focus on precise structural design at the atomic level to explore both the skeletons and pores of COFs has led to the creation of an artificial photosynthesis system for H₂O₂ production, achieving unprecedented photocatalytic efficiency.”