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Focused ultrasound subtly primes human brain to respond, EEG study finds

A research team at Carnegie Mellon University has developed a new noninvasive brain stimulation technique, by showing how focused ultrasound affects the human brain. Using brainwave recordings from human participants, the team found that focused ultrasound can subtly influence brain activity without directly causing neurons to fire. The work clarifies conflicting results in the field and introduces a new approach to noninvasive brain stimulation. The study is published in Nature Communications.

Focused ultrasound has been studied for years, but its effects in humans are not well understood. One challenge is that the technology makes a quiet beeping sound that can trigger hearing pathways in the brain, making it hard to know whether changes are caused by the sound or by the ultrasound itself. Previous studies using MRI scans may also produce misleading signals.

To address these limitations, researchers conducted a resting-state study in 27 human participants using concurrent whole-brain EEG recordings. They compared low-intensity transcranial focused ultrasound (tFUS) alone, a mild electrical brain stimulation called tDCS, and a new approach that combines the two, deemed transcranial electro-acoustic stimulation (tEAS). When used alone, neither ultrasound nor electrical stimulation caused clear, targeted brain responses. However, when combined, they produced strong, specific activity in the targeted area.

Patients with symmetric Parkinson’s disease do poorly with subthalamic stimulation

Patients with symmetric PD can be identified with a simple and straightforward method, a ratio right by left hemibody score equalling 1. This requires no additional time, effort or specialised neuroimaging or laboratory resources.


Background Motor asymmetry is a hallmark of Parkinson’s disease (PD), but ~20% of patients present with symmetric motor signs, which are associated with faster disease progression and poorer dopaminergic response. The impact of motor symmetry on activities of daily living (ADL) outcomes following subthalamic deep brain stimulation (STN-DBS) remains unclear. We hypothesised that patients with symmetric PD experience less ADL improvement post-STN-DBS than asymmetric PD patients.

Methods This was a prospective, quasi-experimental, non-randomised, controlled, international multicentre study with a 6-month follow-up. The primary outcome was the Scales for Outcomes in Parkinson’s Disease-Motor ADL scale. Secondary outcomes included Unified Parkinson’s Disease Rating Scale motor examination and Parkinson’s Disease Questionnaire-8 (PDQ-8). We defined symmetric PD as a right-to-left hemibody motor score equalling 1. We analysed within-group longitudinal changes, between-group outcome differences, effect size and correlations between PDQ-8 and motor changes. We confirmed results in a propensity-score matched subcohort with well-balanced demographic and clinical parameters.

Results We included 200 patients with asymmetric and 54 with symmetric PD. In symmetric PD, ADL remained stable, which was not associated with the observed PDQ-8 improvement. In contrast, in asymmetric PD, ADL improved with a moderate effect size, which correlated moderately with PDQ-8 improvement. In symmetric PD, the absolute risk of experiencing no clinically relevant postoperative ADL improvement was 23.8% higher.

Spontaneous metacognitive experiences and involuntary memories in the laboratory

A recent study published in Consciousness and Cognition provides evidence that everyday mental quirks like déjà vu or tip of the tongue states are natural byproducts of a resting mind. The findings suggest that when a person’s attention is not fully occupied, a wide variety of spontaneous thoughts and reflective feelings naturally emerge into awareness.

The scientists conducted the research to understand if a broad spectrum of unprompted mental experiences could be systematically captured in a laboratory setting. Past research has mostly focused on involuntary memories, which are recollections of personal events that pop into the mind without warning. The team wanted to know if the same boring, repetitive conditions that produce these memories might also generate other spontaneous phenomena.

They specifically focused on metacognition. Metacognition is a term used to describe the brain’s ability to think about and monitor its own processes. While people sometimes use metacognition deliberately, such as trying to gauge how well they learned a topic for a test, it can also happen without effort.

Spontaneous metacognition includes sudden feelings like déjà vu, which is the sensation that a new situation is highly familiar. It also includes the sudden realization that a well known word looks strangely incorrect, a phenomenon known as jamais vu.

“This study was motivated by the observation that many mental experiences—such as déjà vu, tip-of-the-tongue states, or sudden memories—seem to appear spontaneously in everyday life, yet they are usually studied separately in different areas of psychology,” explained study author Krystian Barzykowski, the head of the Applied Memory Research Laboratory at Jagiellonian University and Marie Skłodowska-Curie Postdoctoral Fellow at the Grenoble Alpes University.

Abstract: Consciousness and Cognition.

Everyday mental quirks like déjà vu might be natural byproducts of a resting mind

A recent study published in Consciousness and Cognition provides evidence that everyday mental quirks like déjà vu or tip of the tongue states are natural byproducts of a resting mind. The findings suggest that when a person’s attention is not fully occupied, a wide variety of spontaneous thoughts and reflective feelings naturally emerge into awareness.

The scientists conducted the research to understand if a broad spectrum of unprompted mental experiences could be systematically captured in a laboratory setting. Past research has mostly focused on involuntary memories, which are recollections of personal events that pop into the mind without warning. The team wanted to know if the same boring, repetitive conditions that produce these memories might also generate other spontaneous phenomena.

They specifically focused on metacognition. Metacognition is a term used to describe the brain’s ability to think about and monitor its own processes. While people sometimes use metacognition deliberately, such as trying to gauge how well they learned a topic for a test, it can also happen without effort.

Do we really control our own decisions?

For decades, neuroscientists have explored a fascinating phenomenon in the human brain known as the split-brain experiment. When the connection between the two hemispheres of the brain — the Corpus Callosum — is surgically cut, something extraordinary happens.

Each hemisphere begins processing information independently.

In groundbreaking research conducted by neuroscientist Michael Gazzaniga, scientists discovered that the speaking side of the brain often creates explanations for actions it did not initiate. This phenomenon is known as the Left-Brain Interpreter.

Instead of admitting uncertainty, the brain rapidly constructs logical stories to explain behavior. These experiments revealed how the human mind continuously builds a coherent narrative about our identity, decisions, and sense of self.

The split-brain studies remain one of the most important discoveries in modern neuroscience, raising profound questions about consciousness, decision-making, and the nature of the human mind.

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Mapping human brain cell type origin and diseases through single-cell transcriptomics

Wang P, Zhao D, Lachman HM, Zheng D. Enriched expression of genes associated with autism spectrum disorders in human inhibitory neurons. Transl Psychiatry. 2018;8:13. https://doi.org/10.1038/S41398-017-0058-6

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Tinnitus Is Somehow Connected to a Crucial Bodily Function

Those who have never endured the relentless ringing of tinnitus can only dream of the torment. In fact, a bad dream may be the closest some get to experiencing anything like it.

The subjective sound, which can also be a hissing, buzzing, or clicking, is heard by no one else, and it may be present constantly, or may come and go.

Neuroscientists at the University of Oxford now suspect that sleep and tinnitus are closely intertwined in the brain.

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