Brain region identified that controls collecting behavior

Perhaps the Beanie Baby craze wasn't so weird after all.
Most people have a collection of some kind at some point in their
lives. Indeed, historical studies show that acquiring and retaining
objects, even when they are not necessary for survival, is not only
nearly universal, but also has been part of human behavior since the
earliest human societies. Yet despite the ubiquitous nature of this
trait, very little is known about what drives humans to collect.
By studying patients who developed abnormal hoarding behavior
following brain injury, neurology researchers in the University of
Iowa Roy J. and Lucille A Carver College of Medicine have identified
an area in the prefrontal cortex that appears to control collecting
behavior. The findings suggest that damage to the right mesial
prefrontal cortex causes abnormal hoarding behavior by releasing the
primitive hoarding urge from its normal restraints. The study was
published online in the Nov. 17 Advance Access issue of the journal
Brain.

Hoarding behavior is common among animals; around 70 species hoard
and mostly they hoard food, which makes sense from a survival
standpoint. Studies of hoarding behavior in rodents have shown that
collecting is driven by certain primitive structures deep in the
brain and most mammals, including humans, share these subcortical
regions.

"But human collecting goes beyond items that are solely useful for
survival," said Steven Anderson, Ph.D., UI associate professor of
neurology and lead author of the study. "People often collect art or
stamps or pretty much anything. Clearly there is some higher
structure in humans that modulates the collecting drive and that's
what we think we have tapped into."

The UI team studied 86 people with focal brain lesions - very
specific areas of brain damage – to see if damage to particular
brain regions could account for abnormal collecting behavior. Other
than the lesions, the patients' brains functioned normally and these
patients performed normally on tests of intelligence, reasoning and
memory.

A questionnaire completed by a close family member was used to
identify problematic collecting and the behavior was classified as
abnormal if the collection was extensive; the collected items were
not "useful" or aesthetic; the collecting behavior began only after
the brain injury occurred; and the patient was resistant to
discarding the collected items.

The questionnaire very clearly split the patients into two groups –
13 patients who had abnormal collecting behavior and a majority (73
patients) who did not. Unlike normal collecting behavior such as
stamp collecting, the abnormal collecting behavior of these patients
significantly interfered with their normal daily life. Patients with
abnormal collecting behavior filled their homes with vast quantities
of useless items including junk mail and broken appliances. Despite
showing no further interest in the collected items, patients resist
attempts to discard the collection.

To determine if certain areas of damage were common to patients who
had abnormal collecting behavior, the UI researchers used high-
resolution, three-dimensional magnetic resonance imaging to map the
lesions in each patient's brain and overlapped all the lesions onto
a common reference brain.

"A pretty clear finding jumped out at us: damage to a part of the
frontal lobes of the cortex, particularly on the right side, was
shared by the individuals with abnormal behavior," Anderson
said. "Our study shows that when this particular part of the
prefrontal cortex is injured, the very primitive collecting urge
loses its guidance.

"This finding sheds some light on a ubiquitous, nearly universal
human behavior that we really don't know much about, and we can use
this as springboard to think about normal collecting behavior."

Anderson added that the findings also may have implications for
understanding certain neurological conditions such as obsessive-
compulsive disorder (OCD) where abnormal collecting behavior occurs
but the patient has no readily detectable brain defect.

"Patients with OCD and some other disorders such as schizophrenia,
Tourette's syndrome and certain dementias, can have similar
pathological collecting behavior but we don't have a pointer to
locate where in the brain the problem is occurring," Anderson
said. "Our hope is that our findings with these brain lesion studies
will lead to insights in these conditions as well."

Anderson's co-authors on the study were Antonio Damasio, M.D.,
Ph.D., the Maurice Van Allen Professor of Neurology and head of the
department, and Hanna Damasio, M.D., UI Foundation Distinguished
Professor in the Department of Neurology. The study was funded in
part by a grant from the National Institute of Neurological
Disorders and Stroke.

University of Iowa Health Care describes the partnership between the
UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals
and Clinics and the patient care, medical education and research
programs and services they provide.

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SOURCE: University of Iowa Health Science Relations, 5135 Westlawn,
Iowa City, Iowa 52242-1178
http://www.uihealthcare.com.
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