Specific changes in brain structure after different forms of child abuse

Scientists have found a correlation between specific forms of maltreatment and thinning of the cortex in precisely those regions of the brain that are involved in the perception or processing of the type of abuse. Credit: Fotolia 

Different forms of childhood abuse increase the risk for mental illness as well as sexual dysfunction in adulthood, but little has been known about how that happens.

An international team of researchers, including the Miller School's Charles B. Nemeroff, M.D., Ph.D., Leonard M. Miller Professor and Chair of Psychiatry and Behavioural Sciences, has discovered a neural basis for this association.

The study, published in the June 1 issue of the American Journal of Psychiatry, shows that sexually abused and emotionally mistreated children exhibit specific and differential changes in the architecture of their brain that reflect the nature of the mistreatment.

Researchers have known that victims of childhood abuse often suffer from psychiatric disorders later in life, including sexual dysfunction following sexual abuse.

The underlying mechanisms mediating this association have been poorly understood.

Charles B. Nemeroff

Charles B. Nemeroff and a group of scientific colleagues hypothesized that cortical changes during segments of mistreatment played a role.

To study these potential changes, the researchers used magnetic resonance imaging (MRI) to examine the brains of 51 adult women who were exposed to various forms of childhood abuse.

The results showed a correlation between specific forms of maltreatment and thinning of the cortex in precisely the regions of the brain that are involved in the perception or processing of the type of abuse.

Specifically, the somatosensory cortex in the area in which the female genitals are represented was significantly thinner in women who were victims of sexual abuse in their childhood.

Similarly, victims of emotional mistreatment were found to have a reduction of the thickness of the cerebral cortex in specific areas associated with self-awareness, self-evaluation and emotional regulation.

"This is one of the first studies documenting long-term alterations in specific brain areas as a consequence of child abuse and neglect," said Nemeroff, who is also Director of the Center on Aging.

"The finding that specific types of early life trauma have discrete, long lasting effects on the brain that underlie symptoms in adults is an important step in developing novel therapies to intervene to reduce the often lifelong psychiatric/psychological burden of such trauma."

Christine Heim

"Our data point to a precise association between experience-dependent neural plasticity and later health problems," said Christine Heim.

Jens C. Pruessner agreed that the "large effect and the regional specificity in the brain that corresponds to the type of abuse is remarkable."

The scientists speculate that a regional thinning of the cortex may serve as a protective mechanism, immediately shielding the child from the experience of the abuse by gating or blocking the sensory experience.

However, that thinning of the cortical sections may lay the groundwork for the development of behavioural problems in adulthood.

The results of this study extend the literature on neural plasticity and show that cortical representation fields can be smaller when certain sensory experiences are damaging or developmentally inappropriate.

Journal Reference:
Christine M. Heim, Helen S. Mayberg, Tanja Mletzko, Charles B. Nemeroff, Jens C. Pruessner. Decreased Cortical Representation of Genital Somatosensory Field After Childhood Sexual Abuse. Am J Psychiatry, June 1, 2013

Multiple sclerosis starts in brain’s outer layers

Researchers at the Mayo Clinic and Cleveland Clinic have reversed the traditional understanding of how multiple sclerosis (MS) begins and travels in the brain.

The common view is that the disease starts in the centre of the brain, in the white matter mostly found there, and then moves toward the outer layers, such as the cortex.

But this study, which is unique because it focused on the brain tissues of patients in the very early stages of MS, shows the opposite: that it moves from the outside in.

It begins in the “subarachnoid space,” which surrounds the brain, cushions it and is filled with cerebrospinal fluid. From there it moves into the white matter. This animation shows how the two hypotheses differ.

The findings are also significant because they support the hypothesis that inflammation, not neurodegeneration, is a main driver of the disease.

The authors conclude that it is “overwhelmingly likely” that MS is fundamentally an inflammatory disease, and not a neurodegenerative disease similar to Alzheimer’s.

Researchers are not entirely sure exactly causes MS, but the prevailing theory is that it is an autoimmune disease in which the body’s own immune system attacks and destroys its own myelin, a fatty substance essential to the nervous system. It protects the crucial nerve fibres enable different sections of the brain to communicate.

When myelin is damaged (as in MS), messages between the brain and the body are delayed or blocked, leading to MS symptoms such as blindness, numbness, paralysis, and thinking and memory difficulties.

“Our study shows the cortex is involved early in MS and may even be the initial target of disease,” co-lead author of the study and Mayo Clinic neurologist Dr. Claudia F. Lucchinetti stated.

“Inflammation in the cortex must be considered when investigating the causes and progression of MS”, she says. She and her co-author, Dr. Richard Ransohoff of the Cleveland Clinic, published the results of their study in the New England Journal of Medicine.

Hearing the Teacher's Voice Clearly above the Noise

Children are genetically predisposed to tune on the voice of their mothers, fathers and key people in their lives. become The majority of school-aged children can quickly focus in on the voice of a teacher, even amid the cacophony of the classroom.

This is all thanks to a smart brain that automatically focuses on relevant, predictable and repeating auditory information, according to new scientific research.

Unfotunately, for children who suffer from developmental dyslexia, the teacher's voice may get lost in the background noise of banging lockers, whispering children, playground screams and scraping chairs.

Developmental Dyslexia
Developmental dyslexia is described as a neurological disorder affecting reading and spelling skills and this is detected in 5 to 10 percent of school aged children. Recent scientific studies suggest that children with this condition have difficulties separating important and relevant auditory information from competing background noise.

Research not only confirms those findings but also presents biological evidence that children who report problems hearing speech mixed in with other noise, also suffer from a measurable neural impairment that adversely affects their ability to make use of regularities in the sound environment.

Pattern Recognition
The ability to detect patterns in speech and to sharpen or fine-tune into these repeating elements, is crucial to hearing speech in the presence of other noise because it allows for superior 'selection' or 'tagging' of voice pitch. This is a vital component when picking out a particular voice within background noise.

Tuning in
The brain has a remarkable ability to tune into select or relevant aspects in the soundscape and this is carried out by an adaptive auditory system that continuously changes its activity based on the demands of context. In short the ear is scanning the sounds it hears for familiar and frequencies and repeated tones. This can be a voice talking or a baby crying but it also works for music.

Recent research
In recent research, good and poor readers were asked to watch a video while the speech sound "da" was presented to them through an earphone in two different sessions, during which the brain's response to these sounds was continuously measured.

In the first session, "da" was repeated over and over and over again (in what the researchers call a repetitive context). In the second, "da" was presented randomly amid other speech sounds (in what the researchers call a variable context). In an additional session, the researchers performed behavioural tests in which the children were asked to repeat sentences that were presented to them amid increasing degrees of noise.

"Even though the children's attention was focused on a movie, the auditory system of the good readers 'tuned in' to the repeatedly presented speech sound context and sharpened the sound's encoding.

Repetition encoding
In contrast, poor readers did not show an improvement in encoding with repetition," said Chandrasekaran, lead author of the study. "We also found that children who had an adaptive auditory system performed better on the behavioural tests that required them to perceive speech in noisy backgrounds."

Helping Poor Readers
The study suggests that in addition to conventional reading and spelling based interventions, poor readers who have difficulties processing information in noisy backgrounds could benefit from the employment of relatively simple strategies. Try placing the child in front of the teacher or using wireless technologies to enhance the sound of a teacher's voice for an individual student.
Enhanced Brain Activity
Interestingly, the researchers found that children who suffer from dyslexia showed enhanced brain activity in the variable condition. This may enable these children to represent their sensory environment in a broader and arguably more creative manner, although at the cost of the ability to exclude irrelevant signals i.e. noise.

It is conceivable that the brain of the children who suffer from Dyslexia, is intuitively trying to interact with all the noises and happenings in the room, which under more controlled and quieter circumstances, would allow the child to be more creative, expressive and innovative.

Separating Noise
"The study brings us closer to understanding sensory processing in children who experience difficulty excluding irrelevant noise. It provides an objective index that can help in the assessment of children with reading problems," Kraus says.

For nearly two decades, Kraus has been trying to determine why some children with good hearing have difficulties learning to read and spell while others do not. Early in her work, because the deficits she was exploring related to the complex processes of reading and writing, Kraus studied how the cortex encoded sounds.

The Cortex is the part of the brain mainly responsible for conscious thinking.

There is a close link between hearing, speaking and reading. It is important to note that the children tested had good hearing, i.e. they are examined by a professional and are able to hear an acceptable range of frequencies. It is nonsense to test children with hearing difficulties and assess them as having learning issues.

Make sure there are no physical conditions that are left undetected and undiagnosed, before looking for more complex answers.

If you have concenrs about any of these issues contact a qualified consultant and you can also conatct me if you have any comments or questions.