Summary: Resting brain activity can provide rough maps of the organization of the network in the brain. A new imaging technique allowed researchers to examine cortical architecture in more detail than before in the living brain.
Source: University of Pittsburgh
The brain is made up of a complex series of networks: signals constantly bounce between these networks to allow us to experience the world and move through it effectively.
Understanding how brain networks are organized is key to figuring out how they work. Scientists have learned that brain activity at rest, while sitting in silence, can provide rough maps of the organization of the network. But the maps generated with this approach lose critical detail.
An equivalent street map would help a pedestrian navigate from one neighborhood to another, but would offer little help in getting to a more specific destination.
New research from the University of Pittsburgh shows that the generation of detailed maps is possible with a new imaging method that offers high contrast and high spatial resolution.
The study in monkeys shows that the optical image of the intrinsic signal (ISOI) can reveal the cortical architecture in more detail than previously seen in living brains.
Functional magnetic resonance imaging (fMRI) is the main tool for doctors and researchers to observe brain networks. The procedure is non-invasive and takes about 30 minutes.
Observing brain networks in this way serves a range of interests, from basic research, such as understanding the evolution of the brain through species, to the pathophysiology of the brain of fingerprints. , as in dementia or autism. ISOI has a lot in common with fMRI, but the detail is much richer, which matters considerably given the relatively small sizes of the brain networks.
“Our goal was to study the connections between the motor and sensory areas of the brain. For example, the areas that control the movement of the hand were connected to those that control the movement of the arm and the sensation of the hand,” said Nicholas. Card, lead author and graduate student in bioengineering at Swanson School of Engineering.
“These kinds of connections are critical to how the brain generates skillful movements. If you can understand what those connections should look like in a healthy subject, you can identify the neural basis of the disability.”
Understanding how brain networks are organized is key to figuring out how they work. The image is in the public domain
The most important advancement of ISOI is that it provides an accurate picture of the activity of the brain network in living subjects. The same level of accuracy can be achieved with methods that require researchers to extract the brain of the animal they were studying and examine it using a microscope. Instead, ISOI leaves the brain intact, which means that researchers can examine how networks work in real-life situations, such as learning a new motor skill.
Another important feature of ISOI is that it is based on hemoglobin, which is found in the blood of humans and animals. No tracers, dyes or indicators are needed, which makes this tool versatile and suitable for many species, including humans.
“We compared ISOI results with gold standards in the field, including anatomical tracers and microstimulation and imaging. We found a remarkable match between ISOI and other methods,” said co-author Omar Gharbawie. assistant professor of neurobiology with a secondary appointment in the Department of Bioengineering.
“This is an exciting tool for examining brain connectivity in living animals and shows that spontaneous fluctuations can be reported with great precision for the organization of the network. Our findings also show that the brain reveals its architecture in detail. granular, even when only at rest “.
About this neuroscience research news
Author: Press OfficeSource: University of PittsburghContact: Press Office – University of PittsburghImage: Image is in the public domain
Original search: closed access. “Cortical connectivity is integrated at rest at columnar resolution” by Nicholas S. Card et al. Advances in Neurobiology
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Cortical connectivity is integrated at rest at columnar resolution
Resting state (RS) fMRI is now widely used to obtain information about the organization of brain networks. The inferred functional connectivity (HR) of RS-fMRI is usually macroscale, which is too thick for much of the details of cortical architecture.
Here, we examined whether the RS image with higher contrast and resolution could reveal cortical connectivity with columnar granularity. In longitudinal experiments (~ 1.5 years) in squirrel monkeys, we divided the sensorimotor cortex by dense microelectrode mapping and then recorded RS with intrinsic signal optical images (RS-ISOI, 20 µm / pixel). HR maps were compared with activation evoked by microstimulation and traced anatomical connections.
These direct comparisons showed a high correspondence in the connectivity patterns between the methods. The fidelity of FC maps to cortical connections indicates that the granular details of the network organization are embedded in RS.
Thus, to record RS, the field of view and the effective resolution achieved with ISOI fills a wide gap between fMRI and invasive approaches (2-photon image, electrophysiology). RS-ISOI opens up interesting opportunities for high-resolution mapping of cortical networks in live animals.