Thursday, 15 October 2015
Inhibitory Neurons: More Than Just a Brake
Neuroscientists have known that the brain contains glial cells just as long as they have known that it contains neurons, but only in the past two or three decades have scientists discovered the actual importance of glial cells for communication within the brain. Similarly, neuroscientists have long known that between the large excitatory neurons of the cerebral cortex, there are a multitude of small inhibitory neurons. Once thought to act as simple “brakes” on brain activity, these inhibitory neurons have gradually been found to display far more complex variations in their nature, form, connectivity and function than was originally believed. (more…)
Tuesday, 22 September 2015
Seeing without knowing it : the strange phenomenon of blindsight
This week I’d like to share some information about the fascinating phenomenon of blindsight, along with links to other articles on this subject. People can become blind as the result of damage to the retina, but in rarer cases blindness can occur when both sides of the visual cortex are damaged. The latter situation can lead to the strange phenomenon known as blindsight or unconscious vision, in which people believe that they can’t see anything, but can nevertheless correctly identify the positions of objects in space. If you ask these people where a certain object or point of light is, they will say they don’t know, but if you insist and ask them to take a chance, guess, and point in the direction where they think the object or light might be, most of the time, they’ll point in the right direction. (more…)
Tuesday, 1 September 2015
Memory Loss in Alzheimer’s Reduced for the First Time
On November 4, 1906, German neurologist Alois Alzheimer first described the “particular malady of the cerebral cortex” of his patient Auguste D. Over a century later, this “particular malady” that now bears his name still resists every medication developed so far to treat it: none has yet succeeded in halting the progress of Alzheimer’s disease, or even in slowing it down. At best, some medications reduce some of the disease’s symptoms. In the past decade alone, an estimated $1 billion has been swallowed up by clinical trials of new Alzheimer’s medications, with almost nothing to show for them.
But after decades of disappointment, the tide may be turning at last. A preliminary study published in September 2014 by Dr. Dale Bredesen, in the journal Aging, suggests that the memory losses associated with Alzheimer’s can be reversed through an elaborate 36-point treatment program including dietary changes, exercise, intellectual stimulation and other activities that had already been recognized as Alzheimer’s prevention factors separately. But in this case, it is the unusual step of combining them that seems to have curative value. (more…)
Monday, 10 August 2015
What’s running our show?
Deric Bownds, director of the Biology of Mind program at the University of Wisconsin-Madison, recently gave a lecture at this institution’s seminar series on chaos and complexity. The lecture was entitled “Upstairs/Downstairs in our brains – What’s running our show?” (You can find the full text by following the link at the bottom of this post.) Its subject was the increasingly common distinction, in the literature on the brain, between bottom-up and top-down control. This literature also employs other metaphors for opposing processes in the brain, such as the famous System 1 (fast and unconscious) versus System 2 (slower and conscious), the “upstairs/downstairs” metaphor in the title of Bownd’s lecture, and the distinction between the attention network (the parts in blue in the illustration here) and the default mode network (the parts in orange). (more…)
Saturday, 18 July 2015
Microscopic Synapses and Giant Microscopes
More and more courses are being offered for free online by prestigious universities. Many of these courses deal with various aspects of the cognitive sciences. One such course is “The Fundamentals of Neuroscience”, from Harvard University (see first link below). This course includes various multimedia features, including an excellent 30-minute documentary video entitled “Connectomics: Big Microscopes & Tiny Synapses” (second link below). This video presents the research being done by Professor Jeff Lichtman and his colleagues in his laboratory, who are using images of real human brains to try to map the connections between their neurons—the synapses. (more…)