Researchers from the University of Iowa, along with an international team of neuroscientists, have made a groundbreaking discovery by obtaining direct recordings of the human brain before and after the surgical disconnection of a vital brain hub responsible for language comprehension. The study sheds light on the significance of brain hubs in neural networks and reveals the extraordinary ability of the human brain to compensate for the loss of a hub in a previously unseen immediate manner. The findings have been published in the journal Nature Communications.
Hubs exist in various aspects of life. A bicycle wheel has a hub with spokes emanating from the center, preventing the wheel from collapsing during cycling. Airports serve as hubs that connect cities around the world. Likewise, the human brain has hubs—intersections of multiple neural pathways that facilitate the coordination of brain activity necessary for complex functions like speech comprehension. However, the question of whether highly interconnected brain hubs are replaceable for certain brain functions has been a subject of debate.
Some argue that the brain, which is already a highly interconnected neural network, can readily compensate for the loss of a hub, much like redirecting traffic around a blocked city center. But rare experimental evidence has allowed the neurosurgical and research teams at the University of Iowa, led by Dr. Matthew Howard III and Dr. Christopher Petkov, to investigate and affirm the significance of a specific hub.
By observing what transpires when a hub crucial for language meaning is lost, the researchers have demonstrated both the intrinsic value of the hub and the extraordinary ability of the brain to adapt and partially compensate for its absence. The study was conducted during the surgical treatment of two epilepsy patients. As part of the procedure, the anterior temporal lobe—a hub for language meaning—had to be surgically removed, providing the researchers with an opportunity to study the brain’s response.
Before such surgeries, patients are often asked to perform speech and language tasks in the operating room while electrodes implanted in their brains record activity from nearby and remote areas. This enables the clinical team to effectively treat seizures while minimizing the impact on the patient’s speech and language abilities.
Typically, the recording electrodes are removed after the surgery. However, in this study, the neurosurgery team safely left the electrodes in place or replaced them in the same location, allowing them to capture rare pre- and post-operative recordings. This unprecedented opportunity enabled the researchers to evaluate signals from brain areas distant from the hub, including regions responsible for speech and language processing. Through analyzing the changes in these signals before and after the loss of the hub, the researchers discovered a rapid disruption of signaling followed by an attempt by the broader brain network to compensate.
Dr. Petkov, who also has an appointment at Newcastle University Medical School in the UK, emphasized that the rapid impact on distant speech and language processing areas was unexpected, but what astonished the researchers even more was the brain’s attempt to compensate, albeit incompletely, in such a short timeframe. These findings debunk theories that challenge the necessity of specific brain hubs by demonstrating the hub’s importance in maintaining normal language processing.
Dr. Howard, a member of the Iowa Neuroscience Institute, highlighted how this research underscores the importance of safely obtaining and comparing electrical recordings before and after brain surgery, particularly in cases where a hub might be affected. He also noted that ongoing advancements in neurosurgical treatments and technologies are improving the options available to patients.
The researchers believe that their observations on the immediate impact on neural networks and the brain’s rapid attempt to compensate provide evidence in support of a brain theory proposed by Professor Karl Friston at University College London. Friston’s theory suggests that any self-organizing system at equilibrium strives to maintain order by minimizing its free energy and resisting the universal tendency toward disorder.
The neurobiological results following the disconnection of a brain hub in humans align with several predictions of this theory and related neurobiological theories, demonstrating how the brain strives to restore order after the loss of a hub.
In addition to Dr. Petkov and Dr. Howard, the research team included scientists from the Departments of Neurosurgery, Radiology, and Psychological and Brain Sciences at the University of Iowa, as well as colleagues from Newcastle University, UCL, and the University of Cambridge in the UK, and from Carnegie Mellon University, the University of Wisconsin-Madison, and Gonzaga University in the United States.
*Note:
Ravina Pandya, Content Writer, has a strong foothold in the market research industry. She specializes in writing well-researched articles from different industries, including food and beverages, information and technology, healthcare, chemical and materials, etc. With an MBA in E-commerce, she has an expertise in SEO-optimized content that resonates with industry professionals.