Throughout this semester in my neuroscience seminar, I
had a great honor to listen to Dr. Miller’s talk, the world’s foremost expert
at Frontotemporal Dementia (FTD). As a behavioral neurologist he came across various dementia patients. He became an expert
at knowing what parts of the brain remains spared and what regions are damaged
in patients who suffer from Frontotemporal Dementia, and Alzheimer’s disease. Dr. Miller did not only master the neural
basis of different types of dementia but also he extensively studied the changes of creativity
accompanied by the FTD patients. Knowing where in the brain and when approximately the patient’s
brain will suffer from the spread of dementia could be beneficial in managing and preventing dementia. I have found an interesting article which explains how the neurodegenerative patterns of dementia can
be predicted with the innovative network diffusion model.
Where can art be located in the brain and what part of
the brain is dramatically different in artists? According to Dr. Miller when he would have to choose between the Prefrontal cortex and Parietal Lobe (supramarginal gyrus, anterior parietal
lobule, angular gurys), it would be the latter one that transformed dramatically and allowed
artists to create beautiful paintings. It is known that real artists use both
hemispheres of the brain. The right hemisphere, known as a non-dominant one but it is
undoubtedly dominant for art. Conversely, the left hemisphere is correlated with
the conceptual, symbolic and linguistics aspects of art.
Dr. Miller presented what he found in the history of
both hemispheres injuries. He brought up an example of a famous
Italian cartoonist and film director, Federico Fellini. After Fellini was
diagnosed with a right parietal stroke, his self-portraits became full of
sadness and his cartoons clearly showed the unilateral neglect of the left site
of the word. He was not able to accurately reproduce art and copy it. On the
contrary, left brain injuries are manifested in the loss of conceptual art,
while the ability to copy is spared.
Moving on to the anatomy of AD and FTD, the atrophy of
FTD is localized in the anterior temporal and/frontal lobes. AD patients show
deficit in the posterior parietal and temporal lobes and its degeneration is more diffused than in FTD. Dementia is not a specific disease; it is a mix of symptoms that are caused by different disorders. FTD is diagnosed based on the accompanying symptoms, and disorders that cause
those symptoms. Some of the FTD subtypes are: behavioral variant FTD,
non-fluent PA, semantic aphasia/semantic dementia, logopenic PA, CBD (Corticobasal degeneration),
PSP (Progressive Supranuclear Palsy). Primary progressive aphasia could be caused by the
frontotemporal degeneration or Alzheimer's disease. PPA is a deficit affecting the comprehension and production of language; language deficit depends on the specific area of the network first to degenerate. PPA
can be further subdivided into semantic aphasia (Wernicke's aphasia), logopenic aphasia and
non-fluent (Broca's) aphasia. Semantic dementia is considered to be the most focal
one,specifically overlying the regions of the left anterior temporal lobe. All of these do
not hit the brain diffusely, they hit very precise brain areas; thus
all of them are remarkably predictable.
The other part of Dr. Miller’s talk focused on the actual pattern of creativity in FTD and AD patients. AD is a neurodegenerative
disease in which visuospatial deficits are profound. The struggle with the
precise reproduction of what is seen is common among AD patients but the
ability to see colors and use of forms in art is enhanced. AD patients create abstract art because their ability to reproduce is significantly diminished. One example of AD patient was Utermohlen. He was dyslectic, suffered from the damage to the language network. His ability to create self-portraits slowly diminished as degeneration progressed but he did not stop painting because he was eager to find out what was going on in his brain. In the late stage of AD, he could barely reproduce his face but when he did, it was drawn as if it was erased at the same time. This signaled his nearing death awareness. In FTD patients,
the visual creativity is enhanced due to intact right hemisphere and their artistic skills can develop after the disease onset. Semantic dementia
patients are obsessed with creating art; they spontaneously draw and are very extrinsic.
Dr. Miller directed our attention to a particular PPA patient named Anne Adams. She became fascinated with Bolero and before her symptoms appeared, she decided
to translate each note into a visual form. After the onset of symptoms, her art was
characterized with the enhancement of symmetry and structural detail. As her degeneration progressed, the her copying skills were getting even better. VBM showed an increased gray matter intensity in the right posterior neocortex, while there was a marked atrophy of her language
system, , which explains her ability to copy. In general, FTD patients produce better quality art than AD patients. Dr. Miller concluded that art uses both hemispheres; is it double consciousness? Most likely, art in dementia patients emerges in
association with the left hemisphere dysfunction, and perhaps there is a
rewiring of the posterior brain.
New computational
model has been developed by the researchers and it tracts the way in which
different forms of dementia extend in the brain. This computer program when
applied to the MRI scan of a patient’s brain can predict future degeneration in
that person’s brain over the next few years or decades, scientist say. By
knowing the specific future patters of dementia, patients can prepare themselves
for the upcoming different set of symptoms by making choices regarding their
lifestyles and therapeutic approaches. Science makes improvements every day,
and the early detection of specific patterns in dementia can hold a key to a future
successful treatment that will target the specific brain regions. This finding
also confirms the idea that dementia is caused by abnormal “misfolded”
proteins that spread in the brain and make other proteins misfolded along the
way. The computational model is based on
the flow of toxic proteins and along connected neural fiber tracts. In their experiment scientists
matched the pattern of protein diffusion in a healthy brain to the patterns of
brain atrophy in FTD/AD patients using the diffusion model. Next, MRI was used
to measure the degeneration. They suggested that their speeding mechanism leads
to the observed patterns of dementia. The developer of the diffusion model, Dr.
Raj says: "While the classic patterns of dementia are well known, this is
the first model to relate brain network properties to the patterns and explain
them in a deterministic and predictive manner."
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| Diffusion dynamic model |
Seeley, W. W., B. R. Matthews, R. K.
Crawford, M. L. Gorno-Tempini, D. Foti, I. R. Mackenzie, and B. L. Miller.
"Unravelling Bolero: Progressive Aphasia, Transmodal Creativity and the
Right Posterior Neocortex." Brain 131.1 (2007): 39-49. Print.
Miller, B. L. "Portraits of
Artists: Emergence of Visual Creativity in Dementia." Archives of Neurology 61.6 (2004): 842-44. Print.
It really can drive people to distraction looking after a person with dementia. But that's usually because they don't understand dementia and also don't understand their own caregiver heart.
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