Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: neuroscience – Page 183

Echolocation research sheds light on how whales and dolphins use sound

Toothed whales use sound to find their way around, detect objects, and catch fish. They can investigate their environment by making clicking sounds, and then decoding the “echoic return signal” created when the clicking sounds bounce off objects and return to their ears. This “biosonar,” called echolocation, is rare in the animal kingdom.

Now, a new study by researchers at the Woods Hole Oceanographic Institution, New College of Florida, UC Berkeley, and Oxford University, and published in PLOS One, brings us closer to understanding how dolphin brains have evolved to support .

The research team applied new techniques for mapping networks in the excised brains of dead, stranded cetaceans to examine and compare the auditory pathways in echolocating dolphins and a non-echolocating baleen whale called a sei whale. A partnership with the International Fund for Animal Welfare (IFAW) and others is critical to advancing this work.

All about those faceoffs: Study shows how seasoned hockey fan brains react to key moments in games

What’s happening inside the brain of a passionate hockey fan during a big game? A new study from the University of Waterloo gives a closer look at how the brain functions when watching sports, with data showing how different a die-hard fan’s experience is from that of a casual viewer.

The study, “Understanding the sport viewership experience using functional near-infrared spectroscopy,” is published in Scientific Reports.

The researchers found that during offensive faceoff opportunities, fans deeply invested in hockey showed more activity in a part of the brain called the dorsal medial prefrontal cortex. This area is connected to emotional involvement and evaluative thinking—the mental processing we use to judge and interpret what’s happening around us.

Investigating the Presence of Neurodegeneration Independent of Relapses in MOGAD Compared to Relapsing-Remitting Multiple Sclerosis

This study investigated neurodegeneration in MOGAD, independent of relapses, by comparing clinical, cognitive, and advanced MRI markers in MOGAD, relapsing-remitting MS, and healthy control.

Progression independent of relapse activity (PIRA) is a novel clinical concept in multiple sclerosis (MS) that describes an insidious, persistent disability accrual not related to attacks,1 occurring not only in progressive MS phenotypes but also in the early disease and relapsing-remitting phases (RRMS).1,2 PIRA seems to reflect the presence of chronic smoldering inflammation and subsequent neurodegenerative pathobiological processes in MS.2,3 Cognitive decline independent of relapse activity (cognitive PIRA) can be a sensitive measure of neurodegeneration in MS, even independent of clinical worsening,4,5 and in other neurodegenerative conditions.6,7 Longitudinal structural MRI (sMRI) brain volume loss, measured using MRI scans at different intervals, is a marker of progressive neuroaxonal loss and atrophy and has been used to assess treatment efficacy in MS.8–11 White matter atrophy involves myelin and axonal loss, often caused by Wallerian degeneration. Gray matter atrophy is widespread, affecting areas such as the neocortex, thalamus, hippocampus, and cerebellum, and is mainly due to neuroaxonal loss and neuronal shrinkage rather than demyelination.12–14

Diffusion-weighted imaging (dMRI) is an advanced MRI approach allowing the evaluation of the microstructural brain tissue damage. Neurite orientation dispersion and density imaging (NODDI) is a water-diffusion model, which can interpret changes within one of the three compartments: intra-axonal (neurite density index—NDI), extraneurite (ODI), and free water (isotropic volume fraction—ISOVF).15 The histopathologic validation studies on the NODDI model have shown significant correlations between the ODI and circular variance, a marker of neurite orientation variability, as well as between ODI and myelin staining fraction in MS samples.16 Negative correlations were observed between the NDI and circular variance in healthy controls (HCs) and positive correlations between NDI and markers of myelin, axon, and microglia content.

Alzheimer’s disease pathogenesis: standing at the crossroad of lipid metabolism and immune response

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by macroscopic features such as cortical atrophy, narrowing of the gyri, widening of the sulci, and enlargement of the ventricles. At the cellular level, the pathological characteristics include the extracellular aggregation of β-amyloid (Aβ) forming senile plaques, and the intracellular accumulation of hyperphosphorylated tau proteins forming neurofibrillary tangles. AD leads to the progressive decline of cognitive, behavioral, and social abilities, with no effective treatment available currently. The pathophysiology of AD is complex, involving mechanisms such as immune dysregulation and lipid metabolism alterations. Immune cells, such as microglia, can identify and clear pathological aggregates like Aβ early in the disease.

Aphantasia might be linked to alterations in brain connectivity

Thanks to 7T fMRI, researchers from Paris Brain Institute and NeuroSpin, the CEA’s neuroimaging center, are exploring the neural substrate of visual imagery at very high resolution for the first time. Their results, published in Cortex, pave the way for a better understanding of this fascinating cognitive ability, which some of us entirely lack.

Visual imagery—the ability to mentally summon the image of a landscape, a person, or an object that is not directly observable—varies greatly in intensity from one individual to another. Some people can recall a detailed city map and walk through each street as if watching a movie. Thinking of a loved one, others may barely make out their silhouette and hair color.

Interestingly, about 4% of the population seems completely unable to visualize a scene on demand: this is known as aphantasia, a cognitive peculiarity known for over a century but only recently studied by scientists.

/* */