Frictional instabilities in clay illuminate the origin of slow earthquakes.

The shallowest regions of subduction megathrusts mainly deform aseismically, but they can sporadically host slow-slip events (SSEs) and tsunami earthquakes, thus representing a severe hazard. However, the mechanisms behind these remain enigmatic because the frictional properties of shallow subduction zones, usually rich in clay, do not allow earthquake slip according to standard friction theory. We present experimental data showing that clay-rich faults with bulk rate-strengthening behavior and null healing rate, typically associated with aseismic creep, can contemporaneously creep and nucleate SSE. Our experiments document slow ruptures occurring within thin shear zones, driven by structural and stress heterogeneities of the experimental faults. We propose that bulk rate-strengthening frictional behavior promotes long-term aseismic creep, whereas localized frictional shear allows slow rupture nucleation and quasi-dynamic propagation typical of rate-weakening behavior. Our results provide additional understanding of fault friction and illustrate the complex behavior of clay-rich faults, providing an alternative paradigm for interpretation of the spectrum of fault slip including SSEs and tsunami earthquakes.

Non-invasive neuromodulation can reduce aggressive behaviors in humans: A critical perspective.

Containing aggressive behavior is an ongoing challenge in modern society. Aggressiveness is a multi-level construct that can be driven by emotions (reactive aggression) or can be "cold-blooded" and goal-directed (proactive). Aggressive behavior could arise because of a misjudgment of others' intentions or can follow frontal brain lesions leading to a reduction of impulse control and emotion regulation. In the last few years, interventional and basic research studies adopting Non-Invasive Brain Stimulation (NIBS) have significantly risen. Those techniques have been used both in healthy people, to better understand the role of certain brain regions in psychological processes, and in aggressive subjects to improve their symptoms. From an overview of the literature, focusing on the paper that uses transcranial direct current stimulation (tDCS) to reduce aggressiveness, it emerges that tDCS can (i) enhance facial emotion expression recognition, (ii) improve impulses control, and (iii) affect approach/withdrawal motivation. The current work shows the strengths and weaknesses of tDCS intervention on aggressive individuals, suggesting that this instrument could be adopted on violent people, and paves the way for intervention in some applied settings such as prison.

The PRIAMO study: A multicenter assessment of nonmotor symptoms and their impact on quality of life in Parkinson's disease.

We performed a multicenter survey using a semistructured interview in 1,072 consecutive patients with Parkinson's disease (PD) enrolled during 12 months in 55 Italian centers to assess the prevalence of nonmotor symptoms (NMSs), their association with cognitive impairment, and the impact on patients' quality of life (QoL). We found that 98.6% of patients with PD reported the presence of NMSs. The most common were as follows: fatigue (58%), anxiety (56%), leg pain (38%), insomnia (37%), urgency and nocturia (35%), drooling of saliva and difficulties in maintaining concentration (31%). The mean number of NMS per patient was 7.8 (range, 0-32). NMS in the psychiatric domain were the most frequent (67%). Frequency of NMS increased along with the disease duration and severity. Patients with cognitive impairment reported more frequently apathy, attention/memory deficit, and psychiatric symptoms. Apathy was the symptom associated with worse PDQ-39 score but also presence of fatigue, attention/memory, and psychiatric symptoms had a negative impact on QoL. These findings further support a key role for NMS in the clinical frame of PD and the need to address them specifically in clinical trials using dedicated scales.