memory
neurophilosophy | November 3, 2008Learning and memory are widely thought to involve long-term potentiation (LTP), a form of synaptic plasticity in which a neuron's response to the chemical signals it receives is enhanced. This leads to a strengthening of the neuronal circuit, so that the memory encoded in the circuit can persist for long periods of time.
One of the mechanisms by which this synaptic strengthening occurs is an increase in the density of receptors in the membrane of the neuron receiving the signals. This process, which involves trafficking of receptors within cells, is implicated not only in learning and…
neurophilosophy | October 24, 2008Erasing memories has long been a popular plot device for Hollywood scriptwriters. In the 2004 film Eternal Sunshine of the Spotless Mind, for example, Jim Carrey and Kate Winslet play a separated couple who undergo a radical treatment in order to abolish every trace of the relationship from their brains.
The ability to erase memories is no longer confined to the realms of science fiction. In the current issue of Neuron, researchers from the Medical College of Georgia, in collaboration with others from the Shanghai Institute of Brain Functional Genomics, report that they have rapidly erased…
edyong | October 14, 2008
I have only ever seen one car crash and I remember it with crystal clarity. I was driving home along a motorway and a car heading the opposite way simply veered into the central reservation. Its hood crumpled like so much paper, its back end lifted clear off the tarmac and it spun 180 degrees before crashing back down in a cloud of dust. All of this happened within the space of a second, so the details may be different to what I remember. But the emotions I felt at the time are still vivid - the shock of the sight, the fear for the passengers, the confusion over what had happened.
Many…
neurophilosophy | September 26, 2008Around 15 years ago, researchers discovered that the adult rodent brain contains discrete populations of stem cells which continue to divide and produce new neurons throughout life. This discovery was an important one, as it overturned a persistent dogma in neuroscience which held that the adult mammalian brain cannot regenerate.
Since then, neural stem cells have been the subject of intensive investigation, in large part because of their potential uses in treating neurological conditions such as Parkinson's Disease, stroke and epilepsy. Even so, the function of newly-generated neurons has…
edyong | September 9, 2008There's a growing tendency for advertisers to hype up modern movies with hyperkinetic trailers that end with a blitz of imagery from the film. Seconds after the clip ends, the onslaught of explosions, punches and screeching tyres are probably crystal clear but minutes later, and your recollection of the images starts to fade. By the time you leave the cinema, you can probably only remember a few sparse details, if that.
These experiences jibe with psychological research, which suggests that the photographic clarity that accompanies initial memories tends to fade as they are transferred into…
neurophilosophy | September 5, 2008
In this clip from The Simpsons, Homer explains why he wouldn't benefit from an adult education course: "How is education supposed to make me feel smarter? Every time I learn something new, it pushes some old stuff out of my brain."
As you watched the clip, multiple brain regions were engaged and acted in parallel to generate a coherent conscious experience. For example, the visual cortical in the occipital lobes process the stream of information entering the eyes; the auditory regions in the temporal lobes process the sound entering the ears; and cells in the hippocampus encode…
dmunger | September 3, 2008You may have heard of the idea that people can only remember seven things at a time -- a seven-digit phone number, a license-plate, etc. While the size of working memory actually varies from person to person (it usually ranges from 6 to 8 items), and while people can use strategies like "chunking" to remember more, this observation is basically true.
Except when it's not true. In the 1970s, researchers found that there are actually at least two different and distinct areas of working memory, each with its own separate capacity. One is called the "phonological loop" and is used for recall of…
dmunger | August 29, 2008I've always been a fan of literary studies -- I was an English major in college and I continue to blog about literature on my personal blog. But when I first learned about the concept of alliteration (I must have been in middle school), I was unimpressed. Obviously making a poem rhyme requires some serious skill, since not just one sound but a series of sounds must be repeated at the same point in the poem's meter. Alliteration, by contrast, only requires the repetition of a single consonant sound at the beginning of a few words. Clearly, creating clever combinations of consonant sounds wasn'…
dmunger | August 25, 2008Take a look at this short video -- it's a list of animals. Try to remember as many animals as you can.
If you're like me, you're pretty confident that you will remember the entire list, even after ten minutes or so. In my case, that's not so much because the list names animals that most of us are familiar with. After all, there are plenty of other animals not on my list. How would I remember the precise animals that were included from the thousands of possibilities?
Well, I would remember them -- or think I would -- because they are all names of football teams that play in the NFL. Since I'm…
dmunger | August 18, 2008One of the first things I did after my 90-mile hike with Nora in the North Cascades was play some music on the car stereo. We'd been in the wilderness for seven days, and other than birdsong, we hadn't heard so much as a note for the entire time.
Matching our intuitions about music, researchers have found that music is an important influence on our memories. We associate songs with emotions, people, and places we've experienced in the past. This isn't to say that music is the only influence on memory: the photos I took, the sights I saw, and the words I wrote about my hike will also help to…
dmunger | July 24, 2008Several recent large-scale studies have confirmed a curious finding: Asians are much more likely to have "perfect pitch" than non-Asians. Perfect pitch, more properly called "Absolute pitch," is an extremely rare phenomenon, but it's several times more likely to occur in Asians than in others.
Studies have found that only 1 in 1,500 to 10,000 individuals possess absolute pitch. Part of the ability's rarity is due to the fact that it's really a combination of two abilities: pitch-memory -- the ability to remember what a pitch sounds like, and pitch-labeling -- the ability to name a pitch (A, B…
edyong | July 15, 2008Which of these strings of letters is easier to remember: QKJITJGPI or BBCITVCNN?
Chances are, you chose the latter string, where the nine letters are the combined names of three television networks. This neatly illustrates a fundamental property of human memory - that we remember long strings of information more easily if we can break them down into bite-sized chunks. In this case, a nine-letter string can be divided into three lots of three letters. You probably use similar strategies for remembering telephone numbers, credit card details, or post codes.
Now, Lisa Feigenson and Justin…
neurophilosophy | June 13, 2008WE BELIEVE THAT memory provides us with a faithful record of past events. But in fact, it is well established that memory is reconstructive, and not reproductive, in nature. In retrieval, a memory is pieced together from fragments, but during the reconstruction errors creep in due to our own biases and expectations.
Generally, these errors are small, so despite not being completely accurate, our memories are usually reliable. Occasionally, there are too many errors, and the memory becomes unreliable. In extreme cases, memories can be completely false.
False memory, or confabulation, is…
dmunger | June 12, 2008Boundary extension -- misremembering the boundaries of a scene as wider than they really are -- has been observed in adults as old as 84 and children as young as 6. But for kids much younger than 6, the phenomenon becomes quite difficult to study. How do you ask a 6-month-old whether the picture they're looking at has the same borders as one they saw a few minutes ago? You can't ask them to draw the picture for you -- they can barely sit up, let alone hold a pencil.
Yet the development of boundary extension is an important aspect of the study of vision. Do babies experience the phenomenon…
neurophilosophy | June 6, 2008
Photo by Einat Adar
Our feathered friends provide us with some beautiful examples of the link between brain and behaviour. In some bird species, groups of cells involved in seasonal behaviours die after they have performed their function, but are regenerated by neurogenesis as and when they are needed.
Male songbirds, for example, serenade females; the brain nuclei which produce the vocalizations die when the mating season ends, and regenerate as the next one approaches. Similarly, the Clarke's nutcracker stores tens of thousands of pine seeds in many different caches spread across a…
dmunger | June 5, 2008This article was originally posted on March 27, 2007
When we see a familiar face, or even a photo of a favorite car or pet, we're often flooded with memories from our past. Sometimes just seeing a person or object that's similar to the ones in our memory will trigger recollections we never knew we had. Maybe you've had a memory triggered by a scent or the texture of an object. Sometimes emotions such as happiness or anger will spur vivid memories, too.
A new study adds an unexpected method to the list of ways to spur memories about our past: body position. That's right: just holding your body…
dmunger | June 3, 2008Take a look at the short movie I've linked below (Click on the picture to play. QuickTime required). The movie shows a virtual gripping device (two red balls) lifting rectangular objects and placing them on a conveyor belt. Do you notice anything unusual happening as the objects are being moved?
This is a recording of the image seen by a volunteer using a virtual-reality headset and two force-feedback devices to simulate moving objects by picking them up with a thumb and index finger. The force-feedback devices offer resistance so that the volunteer feels as if he is lifting real objects…
dmunger | June 2, 2008The link below will take you to a short movie (QuickTime Required). You'll see a series of seven easy addition problems, which will flash by at the rate of one every two seconds. Your job is to solve the problems as quickly as possible (ideally, you should say the answers out loud).
Click to watch movie
Apart from the possibility that you might have a better memory for some math facts than others, were any of the problems easier for you?
If you're like most people, you probably responded faster when a problem was repeated, as was the case with 3 + 5. And since the order of operations doesn't…
dmunger | May 27, 2008Inspired by this post, we've decided to devote a week to the analysis of studies from the history of psychology.
Today's post discusses a small fraction of the work done by Hermann Ebbinghaus, a pioneer in the study of memory. Ebbinghaus spent two excruciating year-long periods (1879-80 and 1883-84) painstakingly studying the limits of human memory, using just one experimental participant -- himself.
Ebbinghaus recognized early on that memories were inextricably bound up in their content. It's a very different thing to memorize a poem and an essay, even if the two are the identical length.…
dmunger | May 12, 2008We're pretty good at remembering objects in a complex scene. We can even remember those objects when we move to a different location. However, the research so far has found that memory for the original view is a little better than memory when we've moved to a different location. Much of that research, however, has focused on relatively complex movements: Viewers are asked to remember an array of objects viewed from one side of a room, then are transported to a different part of the room and asked to decide whether the objects are arranged in the same pattern (actually, they're sitting at a…