Imaging Shows Unique Brain Region Tied to Higher Cognitive Abilities

The brain area identified is known to be closely involved in some of the most advanced planning and decision-making processes that people think of as being expressly human.

“We tend to think that being able to plan into the future, be flexible in our approach and learn from others are things that are particularly impressive about humans. We’ve identified an area of the brain that appears to be uniquely human and is likely to have something to do with these cognitive powers,” said senior researcher Prof. Matthew Rushworth , from the department of experimental psychology at Oxford University’s (UK).

Magnetic resonance imaging (MRI) imaging of 25 adult volunteers was used to identify key components in the ventrolateral frontal cortex area of the human brain, and map how these components were connected up with other brain areas. The findings were then compared to equivalent MRI data from 25 macaque monkeys.

Involved in many of the highest facets of cognition and language, the ventrolateral frontal cortex region of the brain is only present in humans and other primates. Some areas are implicated in psychiatric conditions such as drug addiction, attention deficit hyperactivity disorder (ADHD), or compulsive behavior disorders. Language is affected when other areas are damaged after stroke or neurodegenerative disease. A better determination of the neural connections and networks involved should help the understanding of alterations in the brain that are linked with these disorders.

The Oxford University researchers reported their findings February 5, 2014, in the journal Neuron. Prof. Rushworth clarified, “The brain is a mosaic of interlinked areas. We wanted to look at this very important region of the frontal part of the brain and see how many tiles there are and where they are placed. We also looked at the connections of each tile—how they are wired up to the rest of the brain—as it is these connections that determine the information that can reach that component part and the influence that part can have on other brain regions.”

The researchers, utilizing the MRI data, were able to divide the human ventrolateral frontal cortex into 12 areas that were consistent across all the individuals. “Each of these 12 areas has its own pattern of connections with the rest of the brain, a sort of ‘neural fingerprint,’ telling us it is doing something unique,” said Prof. Rushworth.

The researchers were then able to compare the 12 areas in the human brain region with the organization of the monkey prefrontal cortex. Overall, they were very similar with 11 of the 12 areas being found in both species and being connected up to other brain areas in very similar ways. However, one area of the human ventrolateral frontal cortex had no corresponding area in the macaque—a region called the lateral frontal pole prefrontal cortex. “We have established an area in human frontal cortex which does not seem to have an equivalent in the monkey at all,” stated first author Oxford’s Franz-Xaver Neubert. “This area has been identified with strategic planning and decision making as well as multitasking.”

Moreover, the researchers revealed that the auditory areas of the brain were very well connected with the human prefrontal cortex, but much less so in the macaque. The researchers suggest this may be essential for our ability to understand and generate speech.

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