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Category: neuroscience

The frequency-dependent effects of primary hand motor cortex stimulation on volitional finger movement

[Brain stimulation] Taquet et al.: “The effect of motor cortex stimulation on finger flexion is frequency dependent.”

We conducted a prospective study in human patients undergoing awake craniotomies to examine whether the effects of cortical stimulation in hand primary motor cortex (M1) can be frequency dependent and inhibitory.

In 11 participants undergoing clinically indicated awake craniotomies, we delivered bursts of 1–333 Hz stimulation during a finger-flexion task. Synchronized electrocorticography (ECoG), finger joint kinematics, electromyography (EMG), and video were recorded.

Inability to flex the index finger during subthreshold stimulation was noted in 3 participants at frequencies 250 Hz when the electrodes were in locations that induced extension of the forefinger at higher amplitudes. Other than these trials, all stimulation events either induced muscle contractions or had no measurable effect.

A hidden DNA region helps drive frailty, exposing brain and immune links that reshape aging risk

Researchers at McMaster University have identified, for the first time, a novel region of DNA and two associated genes connected to frailty, offering neurological and immune-related insights that might help explain why some older adults are more likely to be frail than others.

The McMaster team’s findings, published in the journal npj Aging, fill an important gap by revealing genetic factors that contribute to the development of frailty. The discovery provides a biological connection to the condition and points toward new avenues for early detection and targeted intervention.

Cellular and molecular landscapes of human tendons across the lifespan revealed by spatial and single-cell transcriptomics

Kurjan et al. map human tendon architecture from embryo to adult using spatial and single-cell transcriptomics. They show embryonic progenitors generate fibrillar, connective, and chondrogenic tendon lineages. Fibroblasts reprogram with age, whereas immune, vascular, and neural cells remain stable. Ruptured adult tendons partially reactivate fetal programs without full regeneration.

Microfluidic chip reveals how living glioblastoma slices resist chemotherapy

Combining microchip engineering techniques with cutting-edge gene profiling, scientists at Columbia University have developed a new way to study drug responses in living slices of human brain tumor cells. The system, using a type of chip called a microfluidic device, has already revealed new details about how these aggressive tumors resist chemotherapy drugs and could help researchers develop more effective treatments.

The work grew from earlier efforts to study glioblastoma tumors removed from patients during surgery. “These samples that we’re getting from our colleagues who resect these tumors clinically, they’re alive, and we can actually do experiments directly on those surgical samples,” says Peter Sims, Ph.D., associate professor of systems biology at Columbia and senior author on the new study, which appears in the journal Lab on a Chip.

Benefits and Harms of Dementia Screening for Family Members of Older Adults: A Randomized Clinical Trial

Alzheimer disease and related dementias screening of adults ≥65 years in primary care had no significant benefits or harms on family member quality of life or psychological well-being.

Question How does screening adults aged 65 years and older for dementia in primary care affect their family members’ health-related quality of life, stress, and perceived readiness to provide care?

Findings In this randomized clinical trial that included 1808 patient-family member dyads, there was no significant difference in benefit of screening to family members, measured by physical and mental component summary scores, and no difference in harm, measured by depression and anxiety between the screen and no screen groups over time.

Meaning These findings suggest that screening older adults for dementia in primary care did not improve or worsen their family members’ quality of life or psychological well-being.

Laser bursts flip nanoscale magnetic vortices at blistering speeds, opening a path to brain-like spintronics

Spintronics are devices that operate leveraging the spin, an intrinsic form of angular momentum, of electrons. The ability to switch magnetic states is central to the functioning of these devices, as it ultimately allows them to represent binary digits (i.e., “0” and “1”) when processing or storing information.

Some of these devices rely on magnetic vortices, nanoscale whirlpool-like patterns of magnetization that influence the alignment of spins. These vortices possess a property known as helicity, which is essentially the direction in which they rotate.

Reliably switching the helicity of magnetic vortices could open new possibilities for both neuromorphic computing systems, devices that mimic the brain’s neural organization, and multi-state memories. So far, however, this has proved challenging, mainly because it requires a synchronized wave-like rotation of spins without disrupting the geometric structure of vortices.

De novo fast motion computation in the primate visual cortex

He et al. suggest that MT and MST neurons can generate velocity selectivity anew by integrating sequential visuotopic activations from the V1 rather than by simple inheritance, as the V1 is no longer direction selective at high speeds. This de novo velocity computation provides a parsimonious explanation for fast motion processing in the primate brain.

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