New research from Australia is challenging
the widely held view that emotions and feelings are the domain of only the
right hemisphere.
Ever
been stuck in traffic when a feel-good song comes on the radio and suddenly
your mood lightens?
Most
people will agree that our emotions and feelings are typically associated with
the right side of the brain; for example, processing the emotion in human
facial expressions is performed by the right hemisphere of the brain.
New
research from Australia published in the journal Neuropsychologia is
challenging the widely held view that emotions and feelings are the domain of
only the right hemisphere.
Dr.
Sharpley Hsieh and colleagues from Neuroscience Research Australia (NeuRA)
studied people with Alzheimer’s disease, semantic dementia, and healthy people
without either disease. People with Alzheimer’s disease lose episodic memory
(‘What did I do yesterday?’) while people with semantic dementia lose semantic
memory (‘What is a zebra?’).
Participants
were played new pieces of music and had to indicate whether the song was happy,
sad, peaceful, or scary, and images were then taken of the patients’ brains
using MRI so that diseased parts of the brain could be compared statistically
to the answers provided in the musical test.
The
study showed that patients with Alzheimer’s and semantic dementia have problems
deciding whether a human face looks happy or sad because the amygdala in the
right hemisphere is diseased.
Patients
with semantic dementia have additional problems labeling whether a piece of
music is happy or sad because the anterior temporal lobe in the left hemisphere
is diseased.
“It’s
known that processing whether a face is happy or sad is impaired in people who
lose key regions of the right hemisphere, as happens in people with Alzheimer’s
and semantic dementia,” said Hsieh.
“What
we have now learnt from looking at people with semantic dementia is that
understanding emotions in music involves key parts of the other side of the
brain as well.”
Hsieh
says that this is the first study from patients with dementia to show that
language-based areas of the brain, primarily on the left, are important for
extracting emotional meaning from music.
“Our
findings suggest that the brain considers melodies and speech to be similar and
that overlapping parts of the brain are required for both,” said Hsieh.
The
article can be found at: Hsieh S et al. (2012) Brain
correlates of musical and facial emotion recognition: Evidence from the
dementias.
——
Source: NeuRA.
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