Articole stiintifice

Autismul si procesarea cuvintelor familiare

Reactiile creierului la cuvinte sunt un predictor al progreselor in
dezvoltarea copiilor cu autism

(articol tradus partial)

Conform unui nou studiu, pattern-ul de raspunsuri ale creierului la cuvinte (la copiii de 2 ani cu tulburare de spectru autist) este un predictor al abilitatilor lingvistice, cognitive si adaptative de la varstele de 4 si 6 ani.

Rezultatele acestei cercetari, publicate in data de 29 mai in PLOS ONE, sunt primele care arata ca un marker cerebral poate prezice abilitatile viitoare ale copiilor cu autism.

“Acest lucru este valabil la 4 ani dupa testarea initiala, indiferent de tipul de tratament de care au beneficiat copiii”, a spus Patricia Kuhl, co-director al Institutului pentru Invatare si Stiintele ale creierului, din cadrul Universitatii Washington.

Douazeci si patru de copii cu autism si 20 copii fara autism, au ascultat o multime de cuvinte familiare si non-familiare in timp ce purtau pe cap o casca cu senzori. Acei senzori au masurat raspunsurile creierului in momentul in care copiii auzeau cuvintele[…].

Apoi, cercetatorii au impartit copiii cu autism in doua grupuri, pe baza severitatii afectarii sociale si au studiat raspunsurile creierului. Copiii cu simptome mai putin severe au inregistrat raspunsuri cerebrale similare cu ale copiilor cu dezvoltare tipica; adica au reactionat puternic la cuvinte familiare (s-a activat aria limbajului localizata in regiunea temporo-parietala din partea stanga a creierului).

Acest fapt ne sugereaza urmatorul lucru: creierul copiilor cu simptome mai putin severe poate procesa cuvintele in maniera asemanatoare cu cel al copiilor fara autism.

Prin contrast, copiii cu afectare sociala severa au inregistrat raspunsuri cerebrale in emisfera dreapta, fenomen care nu a fost observat la copiii cu dezvoltare tipica.[…]

Cercetatorii au evaluat abilitatile cognitive, sociale, emotionale si de limbaj ale copiilor la 2, 4 si la 6 ani. Copiii cu autism care au participat la studiu au beneficiat de tratament intensiv si, per ansamblu, au obtinut scoruri mai bune la testele de comportament. Dar progresele pe toate ariile de dezvoltare au variat foarte mult: cu cat creierul copilului a reactionat mai puternic la cuvinte familiare la varsta de 2 ani, cu atat s-au vazut mai multe progrese la varsta de 6 ani. […]

“Invatarea sociala este una dintre trasaturile definitorii ale omului” spune Kuhl. “Daca creierul tau poate invata de la alti oameni intr-un context social, inseamna ca ai capacitatea de a invata aproape orice.”

Cercetatoarea spera ca aceasta descoperire va conduce la masuratori cerebrale  care sa poata fi folosite cu copiii de 12 luni (sau mai mici) pentru a-i identifica pe cei cu risc de a avea autism. […]

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Articole stiintifice

Pivotal response training si functionarea cerebrala la copiii cu autism

 Using functional magnetic resonance imaging (fMRI) for before-and-after analysis, a team of researchers including a UC Santa Barbara graduate student discovered positive changes in brain activity in children with autism who received a particular type of behavioral therapy.

Work completed at Yale University’s Child Study Center used fMRI as the tool for measuring the impact of Pivotal Response Treatment (PRT) — therapy pioneered at UCSB by Lynn Koegel, clinical director of the Koegel Autism Center — on both lower- and higher-functioning children with autism receiving PRT for the first time. fMRI allows researchers to see what areas of the brain are active while processing certain stimuli — in this case human motion. Comparing pre- and post-therapy data from the fMRI scans of their 5-year-old subjects, the researchers saw marked — and remarkable — changes in how the children were processing the stimuli. Findings from their study, “Neural Mechanisms of Improvements in Social Motivation After Pivotal Response Treatment,” are published in a recent issue of theJournal of Autism and Developmental Disorders.

“The cool thing that we found was that these kids showed increased activation in regions of the brain utilized by typically developing kids,” explained Avery C. Voos, first-year graduate student at the UCSB-based Koegel Autism Center, and one of the lead authors of the Yale study. “After four months of treatment, they’re starting to use brain regions that typically developing kids are using to process social stimuli.

“We can say that we have shifted the way these children are processing low-level social stimuli, and that’s what we want,” she added. “There’s a social deficit in autism, so any improvement toward social interaction really helps with development. That’s what makes this very exciting, and it speaks to the promise and success of PRT.”

A targeted technique meant to improve social engagement among children with autism spectrum disorders, PRT forgoes the focus on specific skills, like block-building, to concentrate instead on so-called “pivotal areas,” such as motivation, in hopes of inducing a cascading effect with similar impact across multiple areas.

“For instance, if you’re orienting to people, socially it may appear more acceptable, but you’re also getting rich information from those people, which will affect the way you’re interacting with people more broadly,” Voos explained. “Say a child wants to draw, and asks for a red crayon while she has her back to me. I say, ‘I can’t understand what you’re asking if you’re not looking at me.’ Once she orients toward me, we provide a contingent response — in this case, giving her the red crayon — and ideally she begins to understand, ‘Hey, me looking at you and asking for what I want gets me what I want.’ Ultimately, the social interaction becomes the reward on its own, which is the ultimate goal.”

The Yale study involved two children, who each received the same amount of therapy — eight to ten hours each week, for four months — bookended by fMRIs looking at predetermined regions of the brain. Small by design, according to Voos, the project was meant to show that PRT does impact processing, and is not simply inspiring learned behavioral changes. It was also intended as impetus for further, more comprehensive study.

“The logical next step is to assess a larger group of children that are the same age as these two, to see whether these improvements were unique to these kids,” Voos said. “We also want to know if the changes we saw remain after treatment. Long-term, it would be amazing to do this with hundreds of kids, in different age groups, to see what differences there may be. I would postulate that the younger we start these kids in treatment, the more improvement we will see in the way that they process social stimuli.”

And therein lies the larger message of this study, according to Voos.

“Early intervention is wonderful,” she said. “It can make serious improvements not only in overt behavior, but potentially in the way children are processing the world around them and the way they’re processing your interaction with them on a daily basis. Even if they’re only minor changes, the fact that they have those shifts, and are potentially processing social stimuli in a more ‘typical’ manner for the rest of their lives, is pretty powerful to think about.”

“Traditional neuro-imagers will say you can’t do MRI with single subjects,” she acknowledged. “This is still giving us a lot of useful information. It might be a different way of using the technology, but we think it’s beneficial. And we don’t think these are random findings. They make sense to us, and it’s exciting.”

Articole stiintifice

Neurostiintele si atasamentul uman


Attachment is the ability to form human relationship bonds.  Individuals vary in their ability to develop social relationships.  The ability to form secure human relationships plays a key role in successful personal and occupational development.

Attachment theory evolved over 50 years ago.  This theory proposes all humans have an innate biological mechanism that supports social engagement.  This engagement is necessary during infancy to encourage nurturance and provision of a safe environment.

Bowlby is credited with describing attachment theory and he proposed three developmental styles of attachment.  These three attachment styles included:

  • Secure attachment: an ability to easily seek and obtain support from others.  This style promotes strong bonds with parents, siblings, friends and later in life allows for bonding with a mate.
  • Anxious attachment: a insecure attachment style where emotional support has often been inconsistent during childhood.  Individuals with anxious attachment develop hypersensitivity to interpersonal rejection and have anxiety in social environments.  They may develop a needy approach to relationships constantly seeking reassurance of the strength of social supports.
  • Avoidant attachment: an insecure attachment style that may have been characterized by early social adverse environments.  Individuals with insecure attachment style built a wall around their life denying a need or interest in human interactions.

Emerging research in social neuroscience is providing a better understanding of brain mechanisms related to human attachment.  Vrticka and Vuilleumier of the University of Geneva in Switzerland recently published an excellent review of the neuroscience of human attachment in the journal Frontiers in Human Neuroscience.

The authors of this review begin by noting research showing attachment has profound effects in the domains of emotion processing, selective attention and memory.  Insecure attachment individuals are hypersensitive to changes in the expression of emotions in others.   Anxious attachments individuals have enhanced attention to threatening cues.  Avoidant attachment individuals inhibit the memory processing of distressful information.

The authors note social approach behavior appears regulated in specific brain regions including the ventral tegmental area, pituitary, striatum and ventral medial orbitofrontal cortex.  Social aversion appears to be regulated through the amygdala, hypothalamus, insula, anterior cingulate and anterior temporal poles.

Social behavior appears to regulated through both affective evaluation (emotional mentalization) and cognitive control systems (cognitive mentalizations).  These systems interact with hormonal and neurotransmitter domains in influencing social interactions.

The neuroscience of human attachment includes emerging research showing the importance of mental state representation of others (theory of mind).  Mothers with high sensitivity to the cries of their own infants during the post partum period show increased gray matter and fMRI BOLD responses in the prefrontal cortex, superior temporal sulcus and fusiform gyrus.  These regions have been identified as key components engaged in being aware of the emotional states of others.

The authors conclude that the neuroscience of human attachment is beginning to outline key common and distinct elements in avoidant and anxious attachment styles.  Attachment styles appear to be influenced by both environmental history as well as neurobiological factors, some of which may have strong genetic contributions.

Future neuroscience of research will need to move experiments into the “real world” and not be limited to task in brain scanners.  Additionally, future research needs to target early intervention studies in children with attachment problems to find the most effective methods to improve social outcomes.

Readers with more interest in this review are directed to the DOI link below where the free full text manuscript can be found.

Vrtička, P., & Vuilleumier, P. (2012). Neuroscience of human social interactions and adult attachment style Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00212