semantic memory

Autism study reveals how a genetic variant rewires the brain

December, 2010

An imaging study has revealed how one of the many genes implicated in autism is associated with an atypical pattern of connectivity between the hemispheres and within and from the frontal lobe.

Many genes have been implicated in autism; one of them is the CNTNAP2 gene. This gene (which is also implicated in specific language disorder) is most active during brain development in the frontal lobe. An imaging study involving 32 children, half of whom had autism, has revealed that regardless of their diagnosis, the children carrying the risk variant showed communication problems within and with the frontal lobe. The frontal lobe was over-connected to itself and poorly connected to the rest of the brain, particularly the back of the brain.

There were also differences in connectivity between the left and right sides of the brain — in those with the non-risk gene, communication pathways in the frontal lobe linked more strongly to the left side of the brain (which is more strongly involved in language), but in those with the risk variant, the communications pathways connected more broadly to both sides of the brain.

The findings could lead to earlier detection of autism, and new interventions to strengthen connections between the frontal lobe and left side of the brain. But it should be emphasized that the autistic spectrum disorders probably encompass a number of different genetic patterns associated with different variants of ASD.

It should also be emphasized that this gene variant, although it increases the risk of various neurodevelopmental disorders (such as specific language impairment, which has also been associated with this gene), is found among a third of the population. So the pattern of connectivity, although not ‘normal’ (i.e., the majority position), is not abnormal. It would be interesting to explore whether other, more subtle, cognitive differences correlate with this genetic difference.

Reference: 

Scott-Van Zeeland., A.A. et al. 2010. Altered Functional Connectivity in Frontal Lobe Circuits Is Associated with Variation in the Autism Risk Gene CNTNAP2. Science Translational Medicine, 2 (56), DOI: 10.1126/scitranslmed.3001344 http://stm.sciencemag.org/content/2/56/56ra80.abstract

Source: 

tags: 

Topics: 

tags problems: 

tags memworks: 

Sleep reorganizes your memories

December, 2010

New studies show how sleep sculpts your memories, emphasizing what’s important and connecting it to other memories in your brain.

The role of sleep in consolidating memory is now well-established, but recent research suggests that sleep also reorganizes memories, picking out the emotional details and reconfiguring the memories to help you produce new and creative ideas. In an experiment in which participants were shown scenes of negative or neutral objects at either 9am or 9pm and tested 12 hours later, those tested on the same day tended to forget the negative scenes entirely, while those who had a night’s sleep tended to remember the negative objects but not their neutral backgrounds.

Follow-up experiments showed the same selective consolidation of emotional elements to a lesser degree after a 90-minute daytime nap, and to a greater degree after a 24-hour or even several-month delay (as long as sleep directly followed encoding).

These findings suggest that processes that occur during sleep increase the likelihood that our emotional responses to experiences will become central to our memories of them. Moreover, additional nights of sleep may continue to modify the memory.

In a different approach, another recent study has found that when volunteers were taught new words in the evening, then tested immediately, before spending the night in the sleep lab and being retested in the morning, they could remember more words in the morning than they did immediately after learning them, and they could recognize them faster. In comparison, a control group who were trained in the morning and re-tested in the evening showed no such improvement on the second test.

Deep sleep (slow-wave sleep) rather than rapid eye movement (REM) sleep or light sleep appeared to be the important phase for strengthening the new memories. Moreover, those who experienced more sleep spindles overnight were more successful in connecting the new words to the rest of the words in their mental lexicon, suggesting that the new words were communicated from the hippocampus to the neocortex during sleep. Sleep spindles are brief but intense bursts of brain activity that reflect information transfer between the hippocampus and the neocortex.

The findings confirm the role of sleep in reorganizing new memories, and demonstrate the importance of spindle activity in the process.

Taken together, these studies point to sleep being more important to memory than has been thought. The past decade has seen a wealth of studies establishing the role of sleep in consolidating procedural (skill) memory, but these findings demonstrate a deeper, wider, and more ongoing process. The findings also emphasize the malleability of memory, and the extent to which they are constructed (not copied) and reconstructed.

Reference: 

Source: 

tags lifestyle: 

tags memworks: 

Topics: 

Building language skills more critical for boys than girls

October, 2010

A study of language and self-regulation skills in toddlers suggests that having a good vocabulary helps boys in particular control their behavior and emotions.

A study involving 120 toddlers, tested at 14, 24, and 36 months, has assessed language skills (spoken vocabulary and talkativeness) and the development of self-regulation. Self-regulation is an important skill that predicts later academic and social success. Previous research has found that language skills (and vocabulary in particular) help children regulate their emotions and behavior. Boys have also been shown to lag behind girls in both language and self-regulation.

The present study hoped to explain inconsistencies in previous research findings by accounting for general cognitive development and possible gender differences. It found that vocabulary was more important than talkativeness, and 24-month vocabulary predicted the development of self-regulation even when general cognitive development was accounted for. However, girls seemed ‘naturally’ better able to control themselves and focus, but the ability in boys was much more associated with language skills. Boys with a strong vocabulary showed a dramatic increase in self-regulation, becoming comparable to girls with a strong vocabulary.

These gender differences suggest that language skills may be more important for boys, and that more emphasis should be placed on encouraging young boys to use words to solve problems, rather than accepting that ‘boys will be boys’.

Reference: 

Source: 

tags memworks: 

Topics: 

tags strategies: 

tags study: 

tags development: 

New advice on how much cognitive abilities decline with age

October, 2010

A new study suggests that inconsistencies in rate of age-related cognitive decline may be partly due to practice effects, but though decline does occur it is slower than some have estimated.

Reports on cognitive decline with age have, over the years, come out with two general findings: older adults do significantly worse than younger adults; older adults are just as good as younger adults. Part of the problem is that there are two different approaches to studying this, each with their own specific bias. You can keep testing the same group of people as they get older — the problem with this is that they get more and more practiced, which mitigates the effects of age. Or you can test different groups of people, comparing older with younger — but cohort differences (e.g., educational background) may disadvantage the older generations. There is also argument about when it starts. Some studies suggest we start declining in our 20s, others in our 60s.

One of my favorite cognitive aging researchers has now tried to find the true story using data from the Virginia Cognitive Aging Project involving nearly 3800 adults aged 18 to 97 tested on reasoning, spatial visualization, episodic memory, perceptual speed and vocabulary, with 1616 tested at least twice. This gave a nice pool for both cross-sectional and longitudinal comparison (retesting ranged from 1 to 8 years and averaged 2.5 years).

From this data, Salthouse has estimated the size of practice effects and found them to be as large as or larger than the annual cross-sectional differences, although they varied depending on the task and the participant’s age. In general the practice effect was greater for younger adults, possibly because younger people learn better.

Once the practice-related "bonus points" were removed, age trends were flattened, with much less positive changes occurring at younger ages, and slightly less negative changes occurring at older ages. This suggests that change in cognitive ability over an adult lifetime (ignoring the effects of experience) is smaller than we thought.

Reference: 

Source: 

tags development: 

Topics: 

tags memworks: 

tags problems: 

tags: 

Music aids Alzheimer's patients in remembering new information

August, 2010

A small study has found that music can help patients with Alzheimer's disease recognize verbal information.

The study involved 13 patients and 14 controls, who listened to either spoken lyrics or lyrics sung with full musical accompaniment while reading the printed lyrics on a screen. The 40 lyrics were four-line excerpts of children’s songs, all characterized by having simple, unrepeated lyrics, repetitive melodies, and a perfect end-rhyme scheme for the four lines. The participants were then given these 40 lyrics mixed in with 40 other similar lyrics, and asked whether they had heard it earlier. Alzheimer’s patients were markedly more likely to recognize those they had heard sung (40% compared to 28% of the spoken). Interestingly, the controls showed no difference, although of course their performance was considerably better (77% and 74%).

It may be that setting new information, such as simple instructions, to music might help Alzheimer’s patients remember it.

On a side note, a recent study found that classical music (four short pieces by different composers) affected the heart rates of people in a vegetative state in the same way as they did those of healthy listeners, suggesting that music affects emotion at very deep level. (see http://www.newscientist.com/article/dn19123-classical-music-moves-the-he...)

Reference: 

Source: 

tags memworks: 

Topics: 

tags strategies: 

tags problems: 

Nouns and verbs are learned in different parts of the brain

February, 2010

An imaging study reveals that different brain regions are involved in learning nouns and verbs.

An imaging study reveals that different brain regions are involved in learning nouns and verbs. Nouns activate the left fusiform gyrus, while learning verbs activates instead the left inferior frontal gyrus and part of the left posterior medial temporal gyrus. The latter two regions are associated with grammatical and semantic information, respectively, while the former is associated with visual and object processing. The finding is consistent with several findings that distinguish nouns and verbs: children learn nouns before verbs; adults process nouns faster; brain damage can differentially affect nouns and verbs.

Reference: 

Source: 

tags memworks: 

tags strategies: 

Topics: 

Foreign language better understood in your own accent

February, 2010

While most foreign language courses try hard to provide native speakers, a new study shows that adults find it easier when the teacher speaks it in the same accent as the student.

While most foreign language courses try hard to provide native speakers, a new study shows that adults find it easier when the teacher speaks it in the same accent as the student. 60 participants aged 18-26, of whom 20 were native Hebrew speakers, 20 new adult immigrants to Israel from the Former Soviet Union, and 20 were Israeli Arabic speakers who began learning Hebrew at age 7-8, has found that while accent made no difference to native Hebrew speakers, both the Russian and Arabic speakers needed less phonological information to recognize Hebrew words when they were pronounced in the accent of their native language.

Reference: 

[167] Leikin M, Ibrahim R, Eviatar Z, Sapir S. Listening with an Accent: Speech Perception in a Second Language by Late Bilinguals. Journal of Psycholinguistic Research [Internet]. 2009 ;38(5):447 - 457. Available from: http://dx.doi.org/10.1007/s10936-009-9099-1

Source: 

tags memworks: 

tags strategies: 

Topics: 

Language helps people solve spatial problems

July, 2010

Signers reveal that more complex language helps you find a hidden object, providing more support for the theory that language shapes how we think and perceive.

Because Nicaraguan Sign Language is only about 35 years old, and still evolving rapidly, the language used by the younger generation is more complex than that used by the older generation. This enables researchers to compare the effects of language ability on other abilities. A recent study found that younger signers (in their 20s) performed better than older signers (in their 30s) on two spatial cognition tasks that involved finding a hidden object. The findings provide more support for the theory that language shapes how we think and perceive.

Reference: 

[1629] Pyers JE, Shusterman A, Senghas A, Spelke ES, Emmorey K. Evidence from an emerging sign language reveals that language supports spatial cognition. Proceedings of the National Academy of Sciences [Internet]. 2010 ;107(27):12116 - 12120. Available from: http://www.pnas.org/content/107/27/12116.abstract

Source: 

tags memworks: 

tags strategies: 

Topics: 

Words influence infants' cognition from first months of life

March, 2010

Like human faces, infants are predisposed to pay attention to words. Now a new study shows that they learn concepts from them from a very early age.

Like human faces, infants are predisposed to pay attention to words. Now a new study shows that they learn concepts from them from a very early age. In the study, in which 46 three-month-old infants were shown a series of pictures of fish that were paired either with words (e.g., "Look at the toma!") or beeps (carefully matched to the words for tone and duration), those who heard the words subsequently showed signs of having formed the category “fish”, while those who heard the tones did not. Categorization was assumed when infants shown a picture of a new fish and a dinosaur side-by-side, looked longer at one picture than the other.

Reference: 

Source: 

tags development: 

tags memworks: 

Topics: 

Sign language study shows multiple brain regions wired for language

April, 2010

Perhaps we should start thinking of language less as some specialized process and more as a particular approach to thought. A study involving native signers of American Sign Language adds to the increasing body of evidence that we process words in the same way as we do the concepts represented by the words; speaking (or reading) is, neutrally speaking, the same as doing.

Perhaps we should start thinking of language less as some specialized process and more as one approach to thought. A study involving native signers of American Sign Language (which has the helpful characteristic that subject-object relationships can be expressed in either of the two ways languages usually use: word order or inflection) has revealed that there are distinct regions of the brain that are used to process the two types of sentences: those in which word order determined the relationships between the sentence elements, and those in which inflection was providing the information. These brain regions are the ones designed to accomplish tasks that relate to the type of sentence they are trying to interpret. Word order sentences activated areas involved in working memory and lexical access, including the dorsolateral prefrontal cortex, the inferior frontal gyrus, the inferior parietal lobe, and the middle temporal gyrus. Inflectional sentences activated areas involved in building and analyzing combinatorial structure, including bilateral inferior frontal and anterior temporal regions as well as the basal ganglia and medial temporal/limbic areas. In other words, as an increasing body of evidence tells us, we process words in the same way as we do the concepts represented by the words; speaking (or reading) is, neutrally speaking, the same as doing.

Reference: 

[453] Newman AJ, Supalla T, Hauser P, Newport EL, Bavelier D. Dissociating neural subsystems for grammar by contrasting word order and inflection. Proceedings of the National Academy of Sciences [Internet]. 2010 ;107(16):7539 - 7544. Available from: http://www.pnas.org/content/107/16/7539.abstract

Source: 

tags: 

tags memworks: 

Topics: 

Pages

Subscribe to RSS - semantic memory