The Brain in Super Agers

My Twitter post on a recently published study of brain structure in a group of high performing older adults received quite a bit of attention (see below).

Felicia Sun and colleagues at Massachusetts General Hospital and Harvard Medical School selected an interesting research design.

A group of elderly subjects between the ages of 60 and 80 years were identified as showing "superaging". This was defined as scoring like young adults on two neuropsychological tests: The Long Delay Free Recall measure of the California Verbal Learning Test and part B of the Trail Making Test.

They then imaged the brain structure and function of the super agers using MRI. The results were compared to two groups: elderly adults without superior cognitive performance and younger adults with age-typical neuropsychological performance.

A key finding from their study was that super agers had brain hippocampal volumes greater than typical older adults and this measure was comparable to young adults.

Super agers also had greater brain volumes than typical older adults in the following regions:

• Anterior temporal cortex
• Medial frontal cortex
• Anterior midcingulate cortex

The authors noted in the discussion section:

"We found support for our hypothesis regarding the structural integrity of the default mode and salience networks, with superagers showing much less atrophy than typical older adults in key nodes of these networks, which we refer to as the "superageing signature".

The authors also note their longitudinal study was not able to identify the factors that may play a key role in super agers. Candidate factors include genetic factors, exercise, diet and social activity levels. These factors are likely to be studied in future research.

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

Figure of hippocampus is an iPad screen shot from the app 3D Brain.

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"Study suggests how 'super aging' older adults retain youthful memory abilities" #neuroscience #feedly https://t.co/DdlXUGbRRp

— W.R.Yates, M.D.✍ (@WRY999) September 14, 2016

Sun FW, Stepanovic MR, Andreano J, Barrett LF, Touroutoglou A, & Dickerson BC (2016). Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging. The Journal of neuroscience : the official journal of the Society for Neuroscience, 36 (37), 9659-9668 PMID: 27629716

Common Brain Anatomy Features in Autism and Schizophrenia

Neuropsychiatric disorder classification challenges clinicians and researcher alike.  Classical approaches have used a distinct non-overlapping categories approach.  Increasingly, research suggests that distinct disorders share clinical and neuroanatomical features.  This means that it might be possible for specific genes and environmental effects to produce more than one disorder.

Cheung et al from the University of Hong Kong, China explored brain structural commonalities between autism and schizophrenia.  Using a novel statistical classification strategy, MRI data were compared in a group of 308 subjects with autism, 352 with first-episode schizophrenia and 801 controls.  The strategy group anatomical differences into those found in autism alone, schizophrenia alone and in both autism and schizophrenia (figure).

The authors used a series of imaging data sets to perform their analysis.  The autism group included several clinical groups including autism, Asperger’s and high-functioning autism.  The schizophrenia group were all first-psychotic episode with some being antipsychotic naïve and some with a history of antipsychotic drug exposure.

The figure from the manuscript shows the grouping for various brain regions grouped by frontal/parietal region/temporal lobe-basal ganglia region and cerebellum.   Both diagnostic groups demonstrated gray matter reductions in the right posterior cingulate, the right parahippocampal gyrus, putamen and left thalamus. 

Subjects with schizophrenia demonstrated many more local regions of atrophy not found in autism including the right and left superior and medial frontal gyrus, right and left cingulated and left insula, caudate, temporal gyrus and amygdala.  The only unique site of gray matter atrophy for the autism group was the left putamen.

The authors note that these two disorders are “indicative of overlapping neuroanatomical phenotype” but do not imply that autism and schizophrenia are a “common entity”.  The authors conclude: “Our findings should therefore encourage further exploration of the potential shared etiologies and better understanding of the mechanisms separating the 2 conditions”.

I think you will see increasing research examining commonalities between what have up until now been considered distinct conditions.  Look for more evidence that distinct disorders have significant phenotype overlap.  Examining these shared features may provide a better understanding of the pathophysiology of a variety of mental disorders.

Figure Provided from PloS One Manuscript

Cheung C, Yu K, Fung G, Leung M, Wong C, Li Q, Sham P, Chua S, & McAlonan G (2010). Autistic disorders and schizophrenia: related or remote? An anatomical likelihood estimation. PloS one, 5 (8) PMID: 20805880