By: Ann Brock
Some autistic patients can talk for hours on a subject and recite facts to the point
that it’s socially inappropriate. But they can’t track what’s going on in their social
context and be able to say, “That’s enough information. Let me move on to something
else.” They have lost theory of mind. They have a deficit in the conscious awareness
of their ability to assess social situations.
Drs. Guy Mittleman and Charles Blaha, professors in behavioral neuroscience in psychology,
have a theory that some of the cognitive deficits associated with autism result from
a disconnection between the cerebellum, located in the back of the brain, and the
frontal cortex. This disconnection is thought to occur as a result of a loss of important
neurons in the cerebellum called Purkinje cells.
Mittleman and Blaha are co-principal investigators on a $2 million grant that will
allow them to investigate this disconnection theory as well as a key element being
regulated in the frontal cortex, dopamine, a chemical transmitter that modulates cortical
Their five-year study will use an animal (mouse) model of autism and has a fourpronged
approach: Mittleman will study the behavior of the animals in a cognitive task; Blaha’s
neurochemistry lab will look at the ability of the cerebellum to release dopamine
in the mouse frontal cortex; Dr. Heck Detlef of the UT Health Science Center will
look at electrophysiological events that occur along the nerve pathways from the cerebellum
to the cortex; and Dr. Dan Goldowitz, a neuroanatomist from Canada, will map physical
anatomy of the cerebellum-cortex connection.
The grant is the first one to propose that there is a distinct association between
the loss of Purkinje cells in the cerebellum and frontal cortex function. Mittleman
says that the team has been researching autism at least five years.
“I think our conceptualization of the problem is pretty far advanced, and it’s different
than a lot of other people’s. Other scientists are searching for what sort of brain
damage underlies autism. We have a relatively refined hypothesis.”
Blaha says the study is a novel exploration.
“Our research presents a unique opportunity to investigate the link between the cerebellum
and cortex. It is our hope that this will lead to new lines of investigation and methods
of treating autism.”