'Now we know where to target people's brains to attempt to improve their speech'
For the first time, Northwestern Medicine scientists have pinpointed the location of dysfunctional brain networks that lead to impaired sentence production and word finding in primary progressive aphasia (PPA), a form of dementia in which patients often lose their language rather than their memory or thought process.
Illustration of the three brain regions associated with speech production and the networks between them that, when broken, lead to speech impairments. Solid orange lines depict significantly lower connectivity between brain regions (in red) in PPA. IFG = Inferior Frontal Gyrus; MTG = Middle Temporal Gyrus; ATL = Anterior Temporal Lobe. PPA = Primary Progressive Aphasia; PPA-G = Nonfluent/agrammatic variant of PPA; PPA-L = Logopenic variant of PPA; PPA-S = Semantic variant of PPA.
Credit: Northwestern University
With this discovery, the scientists have drawn a map that illustrates three regions in the brain that fail to talk to each another, inhibiting a person's speech production, word finding and word comprehension. For example, some people can't connect words to form sentences, others can't name objects or understand single words like "cow" or "table."
The map can be used to target those brain regions with therapies, such as transcranial magnetic stimulation (TMS), to potentially improve an affected person's speech.
"Now we know where to target people's brains to attempt to improve their speech," said lead author Dr. Borna Bonakdarpour, assistant professor of neurology at Northwestern University Feinberg School of Medicine's Cognitive Neurology and Alzheimer Disease Center and a Northwestern Medicine neurologist.
PPA occurs in patients with neurodegenerative disorders, including Alzheimer's disease and frontotemporal degeneration.
Interactions among three main regions in the brain is responsible for how people process words and sentences. PPA occurs when there is a lack of connectivity among these areas. Different patterns of connectivity failure among these regions can cause different subtypes of PPA.
The findings will be published Sept. 1 in the journal Cortex. The large study (73 patients) recruited from the extensive pool of patients with PPA at Northwestern's Cognitive Neurology and Alzheimer Disease Center, one of the largest centers in the world.
The study used functional MRI, which monitors brain activity by detecting blood flow, to locate the regions of the brain that are talking to each other or not. That cannot be shown with structural MRI.
Previous research used structural MRI to locate only regions of the brain that had atrophied, and scientists did not clearly know how physiological impairment in these regions correlated with symptoms a patient was experiencing.
This study is novel because it examined brain regions that were still functional (had not atrophied) and focused on the networks among the functional regions to see if they were connecting or not. This allowed the scientists to correlate the functional areas in the brain with symptoms of patients with PPA.
"Previous studies of structural changes in the brain were like archeology, in which scientists were locating areas of the brain that had already died," Bonakdarpour said. "But we are looking at the parts of the brain that are still alive, which makes them much easier to target with treatment."
Bonakdarpour and his colleagues have begun testing TMS on the three targeted brain regions in healthy individuals with the goal of applying it to patients with PPA in a future clinical trial.
Funding for this paper was provided by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health (NIH), grants K23 DC014303-01A1, R01 DC008552 and 013386, and the National Institute of Neurological Disorders and Stroke of the NIH, grant NS075075 AG056258.
Kristin Samuelson | EurekAlert!
Two commonly used uveitis drugs perform similarly in NIH-funded clinical trial
11.09.2019 | NIH/National Eye Institute
Gene Coding Error Found in Rare, Inherited Form of Lung-Scarring Disorder Linked to Short Telomeres
11.09.2019 | Johns Hopkins Medicine
Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.
This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.
Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.
If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...
Researchers from Chalmers University of Technology have demonstrated a detector made from graphene that could revolutionize the sensors used in next-generation space telescopes. The findings were recently published in the scientific journal Nature Astronomy.
Beyond superconductors, there are few materials that can fulfill the requirements needed for making ultra-sensitive and fast terahertz (THz) detectors for...
A supersolid is a state of matter that can be described in simplified terms as being solid and liquid at the same time. In recent years, extensive efforts have been devoted to the detection of this exotic quantum matter. A research team led by Tilman Pfau and Tim Langen at the 5th Institute of Physics of the University of Stuttgart has succeeded in proving experimentally that the long-sought supersolid state of matter exists. The researchers report their results in Nature magazine.
In our everyday lives, we are familiar with matter existing in three different states: solid, liquid, or gas. However, if matter is cooled down to extremely...
10.09.2019 | Event News
04.09.2019 | Event News
29.08.2019 | Event News
16.09.2019 | Information Technology
16.09.2019 | Ecology, The Environment and Conservation
16.09.2019 | Physics and Astronomy