Happy New Year to All! Hoping everyone has a healthy, happy and productive year in 2015.

I have been working on a topic list for 2015. I will be following my pattern of focusing on a specific brain research topic each month.

During the month I will post primarily on that topic after reviewing relevant research abstracts and manuscripts.

The topic list is taken from areas showing the most reader interest as well as covering area not recently reviewed.

I occasionally post off topic when a specific issue of importance arises.

The topic outline for 2015 will be:
January: Diet, Weight Loss and the Brain
February: Exercise
March: Parenting
April: Attention deficit disorder
May: Conduct disorder
June: Alzheimer's disease
July: Bipolar disorder
August: Social anxiety disorder
September: Migraine headaches
October: Neuropsychology
November: Brain imaging
December: Genetics

Brain Posts aims to select brain research relevant to translation to better clinical care for brain disorders.

Additionally, the blog provides an incentive for me to continue reading, learning and trying to keep up with key brain research advances.

Today's photo is from my files of an edited photo from the Rhema church Christmas lights.

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A key feature in anorexia nervosa is the disturbance in perception of the body.

This perceptual disturbance is encapsulated in criteria 3 from DSM-5:

 "Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape evaluation, or denial of the seriousness of the current low weight"

 Santino Guadio from Italy and colleagues recently published a nice summary of the support for body image disturbance in anorexia nervosa. This study focused on research in the neuropsychology of anorexia nervosa.

This review is informative in outlining the components involved in sensory perception.

Here are the key findings from their review following their perception components outline.

Tactile perception
What it is: identifying touch stimuli and discriminating differences in stimuli
How it is tested: finger identification test, tactile estimation task (estimating distance between two tactile stimuli in different body sites
Findings in anorexia nervosa: Patients with anorexia nervosa perform poorly on identifying finger perception when blindfolded and two fingers are stimulated. Anorexia nervosa is also associated with overestimation of distance between stimulation sites over multiple body parts

Haptic perception
What it is: ability to identify shapes by touch when no visual input is available
How it is tested: Identifying figures and shapes with eyes closed using hands for sensory input
Findings in anorexia nervosa: Patients with anorexia nervosa perform more poorly than controls on correctly identify shape and form when unable to see an object. This deficit appears to be present during both active illness with weight loss and persists following weight restoration.

Propioception
What it is: identification of body and limb position in space
How it is tested: identification of right-left orientation, ability to place a rod in a vertical postion as body position is modified and no visual sensation is provided
Findings in anorexia nervosa: Patients with anorexia nervosa show impaired spatial orientation perception as well as deficits in correctly identifying right-left orientation.

Haptic-visual-proprioception integration:
What it is: Ability to estimate correct physical properties using both haptic and visual stimuli
How it is tested: Two objects of identical weight but difference size are presented for touch and sight input. Subjects estimate weight of two objects relative to each other
Findings in anorexia nervosa: Subjects with anorexia nervosa show reduction in size-weight performance and reduction integration of visual and haptic information.

Visual-tactile-proprioception integration:
What it is: use and integration of three sensory modalities, sight, touch and body position
How it is tested: rubber hand test where subjects estimate position of left index finger before and after visuotactile stimulations.
Findings in anorexia nervosa: Patients with anorexia nervosa show impairment in two components of visuo-tactile-propioception integration

Interoceptive perception:
What it is: ability to identify and process internal bodily sensations such as heartbeart, intestinal activity, hunger, pain
How it is tested: participants are asked to count their own heartbeats and this count is compared to actual heart rate. 
Findings in anorexia nervosa: Patients with anorexia nervosa show impaired perception of heartbeat compared to controls

The authors note they found a relatively few well-designed studies of perception in anorexia nervosa. 

Although the number of studies is small, this review supports a multi-modal impairment in perception in patients with anorexia nervosa compared to controls.

The authors note perception is known to be processed through the brain parietal lobe. They propose that parietal lobe dysfunction may impair perception in anorexia nervosa. This perceptual impairment may contribute to the body image disturbance found in the illness.

Look for an expansion of studies of perception in anorexia nervosa. Pairing neuropsychological perception studies with advanced brain imaging research techniques may be powerful strategy.

Readers with more interest in this topic can access the free full-text manuscript by clicking on the citation link below.

Figure of parietal lobe is from an iPad screenshot from the app Brain Tutor.

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Gaudio S, Brooks SJ, & Riva G (2014). Nonvisual multisensory impairment of body perception in anorexia nervosa: a systematic review of neuropsychological studies. PloS one, 9 (10) PMID: 25303480

Brain research in anorexia nervosa presents several challenges.

Current knowledge of cognitive function in anorexia supports impairment in set shifting and global brain processing or central coherence.

However, there are two issues that complicate understanding the underlying brain effects in anorexia nervosa.

First, individuals with anorexia nervosa often have additional anxiety and mood disorders. It can be difficult to tease out the specific effects of anorexia nervosa from the effects of these comorbid conditions.

Second, fasting and starvation are common metabolic issues in anorexia. These metabolic stresses can also influence brain function.

Sarah Pender and colleagues from University College London and Spain recently published a research study on the neuropsychology of starvation.

The key elements of their study included the following elements:

• Subjects: Healthy females recruited by poster in a university sample. Subjects were required to not have a lifetime history of any psychiatric disorder including anorexia nervosa.
• Measures: A test of set-shifting ability using a test called the rule-change task. A test of local versus global cognitive processing style. A second test of global processing known as the group embedded figures task.
• Metabolic status: Each subject was studied on the above measures after eating and following a period of 18 hours of fasting. 

The authors then compared performance on these neuropsychology tests in the fasting versus satiated state. The main findings from the study included findings in set-shifting and central coherence.

Set-shifting: Performance on set-shifting was not slowed or impaired in the fasting state compared to the satiated state. However, fasting appeared to increase the difficulty (or effort) to set shift.

Central coherence: During the fasting state, subjects shifted processing to a stronger local processing style and a weaker global processing style. This is consistent with reduced central coherence with fasting.

A relevant potential confounding variable in this type of task is the contribution of anxiety and depression in neuropsychological task performance.

I previously collaborated with Dr. Rebecca Marshall and other colleagues at the Laureate Institute of Brain Research in a study of neuropsychological function in a group of women with a variety of eating disorders. In this study, we found subjective anxiety ratings contributed to a significant about of variance in neuropsychological performance in eating disorders. Additionally, we found executive function impairment, a component of central coherence in 30 % of the clinical sample.

Pender and colleagues looked for effects of anxiety and depression in their study and did not find any confounding effects. Obviously, their sample was likely to only have minimal sub-clinical levels of anxiety/depression given the requirement for no current or lifetime psychiatric problem for enrollment.

The authors conclude even short-term fasting "might trigger weak central coherence, and thus play a role in maintaining behaviors characteristic of AN". 

The authors also note the brain effects of fasting, starvation and anorexia nervosa may have difficulty participating in psychotherapy. Psychotherapy requires a more global processing style to be effective.

Readers with more interest in this research can access the free full-text manuscripts by clicking on the PMID link in the citations below.

Photo of brain corpus callosum activated during right-left brain coherence is from an iPad screen shot from the 3D Brain app.

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Pender, S., Gilbert, S., & Serpell, L. (2014). The Neuropsychology of Starvation: Set-Shifting and Central Coherence in a Fasted Nonclinical Sample PLoS ONE, 9 (10) DOI: 10.1371/journal.pone.0110743

Billingsley-Marshall RL, Basso MR, Lund BC, Hernandez ER, Johnson CL, Drevets WC, McKee PA, & Yates WR (2013). Executive function in eating disorders: the role of state anxiety. The International journal of eating disorders, 46 (4), 316-21 PMID: 23354876

In November I will be looking at some research research in eating disorders.

On my first look at some of important research these five studies stood out for more review.

I will be posting more on several of these studies in the next few weeks.

You can click on the manuscript title to go to the abstract.  All studies have free full-text manuscripts that can be access through the abstract link.

The Neuropsychology of Starvation
One of the key problems in studying anorexia nervosa is the isolation of psychological effects from the effects of starvation on the brain. In this study, 60 healthy female subjects were studied after 18 hours of starvation and again when satiated. Short-term starvation was linked to changes in set-shifting and central coherence.

Resting State Connectivity in Anorexia Nervosa
In this study, 35 subjects with anorexia nervosa were studied using resting state functional magnetic resonance imaging. The study found increased connectivity between the angular gyrus and the fronto-parietal brain ciruit. Additionally, anterior insula connectivity was linked to deficits in interoceptive awareness.

Neuropsychology of Body Perception in Anorexia Nervosa
Patients with anorexia nervosa commonly display impaired perception of body shape and size. They often feel "fat" with body part size misperception. This manuscript reviews studies of nonvisual multisensory neuropsychological performance in anorexia nervosa. The review found support for deficits in tactile and proprioreceptive function in patients with anorexia nervosa.

Body Fat Distribution in Anorexia Nervosa
This literature review examined studies of body fat distribution before and during weight loss and with weight restoration. The authors found key differences between body fat distribution patterns in adolescents with anorexia nervosa compared to adult women with anorexia. The authors note body fat loss and re-accumulation may be an important metabolic and nutritional component of anorexia nervosa treatment.

Anorexia Nervosa Treatment Outcome After Urgent Hospitalization
This study examined the effect of several variables on outcome following urgent inpatient hospitalizations. Several psychological variables failed to contribute to poor outcome. However, lower BMI at admission was linked to several poor outcome measures.

Photo of lorikeet is from the author's files.

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