Leukoaraiosis and Lacunes – A Very Brief Overview

As people age, it is common for their brain white matter to change. These changes often appear as bright white spots on T2-weighted MR scans. These areas or spots of hyperintensity (i.e., white matter hyperintensities {WMH}) are also called leukoaraiosis (LA). Researchers are still investigating the exact nature and pathology of these abnormalities but our understanding of them is increasing. They most often seem to start around the lateral ventricles and spread from there, although it is possible to have punctate WMH throughout the brain white matter (i.e., WMH that are not connected to other regions). WMH on brain MRIs represent rarefaction of the white matter, including swelling, demyelination, and damage, although the exact nature and combination of the white matter changes is not known. These WMH can interfere with normal cognitive functioning, including processing speed, attention, inhibition, as well as global executive functioning (although these claims are still being investigated).

Other damage to white matter includes lacunes, which are little holes in the brain, much like the holes in Swiss cheese. They are caused by mini infarcts, or strokes, or other processes. Most of the time they are due to “silent strokes”, or strokes that are small enough that the person does not have any noticeable stroke symptoms. These lacunes can have similar impact on cognition as WMH. Both WMH and lacunes are related to vascular risk factors, such as hyper- or hypo-tension, diabetes, etc.

Optical Illusions That Make You Fatter and Your Wallet Lighter

“Eat from small plates, drink from taller glasses.” Optical illusions lead us to eat and drink more, as illustrated by the examples in this article. There’s an old saying in cuisine…”the first bite is with the eye.”

Interesting article. I’m not sure if there is empirical data to support it but it does show that our perception of our food can affect how much we eat. Our actions are affected by so many different things, many of which we might not be aware.

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Word Superiority Effect and Parallel Processing

WordsOne experiment about cognitive brain functioning is the word superiority effect findings of Dr. Reicher in 1969. In this experiment either a word or a non-word (string of letters) is flashed on a screen. The subject is asked if the stimulus contained one of two letters, say a “C” or an “E”. When the stimulus did not resemble a word (e.g., XXCX) subjects were correct in identifying the target letter about 80% of the time. When the string of letters was similar to a word but not one (e.g., FELV) the subjects also correctly identified the target letter 80% of the time. However, the interesting finding was that when the stimulus was a word (e.g., TEND), subjects were correct in identification 90% of the time. So the word superiority effect is that subjects are most accurate in identifying a target letter when it is contained in a word as opposed to a string of letters.

This lends support to the theory that there are things that we can process in parallel and that that parallel processing (or parallel activation of word and letter) can be beneficial at times (such as helping subjects correctly identify individual letters more often when the letter is contained within a word rather than in a random string of letters). In other words, the whole word is recognized before all the letters individually are recognized. This then speeds up or aids processing because there are now a couple routes, per se, to that letter; there is the visual stimulus (seeing the letter) and the linguistic information (knowing that the letter is in the word) that both are activated and help people recognize letters better.

Image by uncommonmuse.