Using one of the biggest neuroscience breakthroughs in recent years, researchers at MIT mapped the most detailed chart of the human cerebral cortex to date, showing the intricacies of how the functional networks of the brain are organized. The study, published in Neuron, mapped out 24 different networks that orchestrate everything from processing social interactions to analyzing sensory input.

This was indeed an exciting advance in cortical functionality, and neuroscientists Robert Desimone, John Duncan, and Reza Rajimehr allowed the highly engaging use of functional magnetic resonance imaging: mapping activity while participants viewed movie clips. It afforded quite a new approach in brain activities for a better understanding of the surroundings and opens new doors for neuroscience. Cerebral Cortex and Its Complex Networks The cerebral cortex is the outer layer of the human brain, and is critical in advanced cognitive functions, such as sensory processing and complicated behavioural responses. Over the last couple decades, neuroscientists have proposed a variety of different brain networks in this region, many using fMRI data from subjects who were either at rest or doing specific, isolated tasks.

Yet, the inability of these classical approaches to study neural activity outside of isolated, task-specific networks provided only a partial understanding of cortex functionality.

With movie clips as stimuli, the MIT team could stimulate a far more comprehensive range of cortical regions. Given that this study was performed under a very naturalistic setting, the researchers could see exactly how different cortical networks interact with each other to process complex, real-world stimuli. Typically, one would hardly perceive all varieties of cortical networking while at rest or in a single-task environment.

Techniques such as those used in the MIT provided 176 participants with an hour of different movie clips while their brain activity was being followed through the use of high-resolution, 7-Tesla MRI scanners. This sort of stimulus helped expose many cortical networks in such a way that most studies have failed in exposing because only small regions of the brain were being turned on at any given time.

They used machine learning algorithms to map these unique activation patterns across different cortical areas, demonstrating that variations in 24 networks-each linked to specific brain functions-existed. Some of them were obvious and appeared within the sensory areas of the visual and auditory cortices. Others actually revealed specialized functions for processing language, recognizing social interactions, and deriving meaning from sensory cues. This provides a new perspective through which the brain can be studied under more naturalistic conditions, with increased spatial and functional resolution for each network.

According to Desimone, the study has yielded critical insights into how the brain processes stimuli of everyday life. “This is a new approach which uncovers something different from conventional approaches in neuroimaging,” he adds. Instead of a full view of each of the networks, this yields fresh hypotheses for further investigation, with the enormous potential of naturalistic brain mapping in pushing the boundaries of cognitive neuroscience. The most salient series of findings, first, was with regard to higher-order cognitive functions that involved executive control networks in decision-making and attention regulation. Activity noticeably increased in transitions between different movie clips, indicating that these executive control networks had a facilitating role in the adaptation of the brain to new stimuli.

They also noticed a “push-pull” interaction between executive control networks with other feature-specific networks-for instance, faces or actions. When the executive control networks went active, the feature-specific networks go lower in their activity and vice-versa.

It would suggest that the high-level networks in the cerebral cortex are set up in a dynamic, hierarchical fashion that suppresses or activates certain regions depending on the task that a particular region is currently working with. As Rajimehr noted, in this type of hierarchic organization, the brain can very preferentially allocate attention and other resources and becomes most active when ambiguity or a complex stimulus is present. Future Research and Clinical Potential The new map of the cerebral cortex contributes not only to neuroscience theory but also possibly to revolutionizing clinical practices. First, this accurate mapping of sensory, social, and language-processing networks has immediate implications for neurological and psychiatric disorders diagnosis and treatment.

For example, such a study may detail abnormalities within specific cortical networks in conditions such as autism spectrum disorder, schizophrenia, and ADHD, in which social and executive function networks are normally impaired.

A second use of the theory is that attention-related disorders might later be treated optimally once the push-pull dynamics of executive control networks were understood. As research unfolds, it now seems possible that scientists will have either pharmaceutical or behavioural treatments to selectively enhance or suppress a given network, thus allowing personalized treatments for cognitive disorders.

Uncharted Territories and New Hypotheses:

These studies also unveiled hitherto uncharted networks, including a region in the prefrontal cortex that is hyperresponsive to visual scenes. This newly identified network may significantly contribute to environmental context and spatial memory processes and opens new dimensions in research on memory-related disorders such as Alzheimer’s disease.

Yet, further research will continue to explore the specific functions within such networks. Thus, regions in this social processing network may each specialize in face and body recognition or emotional context. Such detailed mapping may allow a finer understanding of how different aspects of social cognition are integrated and help develop therapeutic approaches in clinical psychology and cognitive therapy.

A Paradigm Shift in Brain Research 

This work by the team from MIT represents a paradigm shift in the way we research the brain. The naturalistic observation of neural responses to complex stimuli-a more ecologically valid and complete way of mapping brains-can document how our brains react to real stimuli and, thus, allow researchers to make more accurate models of how our brains really work.

Desimone underlines the significance of this shift: “It’s giving us a new view into the operation of the entire cortex during a more naturalistic task than just sitting at rest.” This use of interactive stimuli that provoke brain responses might be a different criterion in neuroscientific research and could, thus, unleash any cascade of other networks and insights. The construction of an integral topographic mapping of the cerebral cortex is enormous in importance and extent. The MIT study shows mappings of 24 different networks in naturalistic conditions and gives a far more important view of complexity relating to the human brain than what can be so far reassuring on cognitive processes, sensory perception, and social interactions. This research serves as a rich ground for further study of the cerebral cortex in unprecedented detail and, indeed, offers exciting prospects for neuroscience theory and clinical application.

Further research on this “map” of the cerebral cortex has made the possibilities for major breakthroughs in our knowledge of the mind—and treatment of its disorders—almost limitless.

Dr. Prahlada N.B
MBBS (JJMMC), MS (PGIMER, Chandigarh). 
MBA (BITS, Pilani), MHA, 
Executive Programme in Strategic Management (IIM, Lucknow)
Senior Management Programme in Healthcare Management (IIM, Kozhikode)
Postgraduate Certificate in Technology Leadership and Innovation (MIT, USA)
Advanced Certificate in AI for Digital Health and Imaging Program (IISc, Bengaluru). 

Senior Professor and former Head, 
Department of ENT-Head & Neck Surgery, Skull Base Surgery, Cochlear Implant Surgery. 
Basaveshwara Medical College & Hospital, Chitradurga, Karnataka, India. 

My Vision: I don’t want to be a genius.  I want to be a person with a bundle of experience. 

My Mission: Help others achieve their life’s objectives in my presence or absence!

My Values:  Creating value for others. 

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