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A new study reports that certain brain regions interact more closely, while others are less engaged, in people with higher intelligence.

Differences in intelligence have so far mostly been attributed to differences in specific brain regions. However, are smart people’s brains also wired differently to those of less intelligent persons? A new study published by researchers from Goethe University Frankfurt (Germany) supports this assumption. In intelligent persons, certain brain regions are more strongly involved in the flow of information between brain regions, while other brain regions are less engaged.

Earlier this year, the research team reported that in more intelligent persons two brain regions involved in the cognitive processing of task-relevant information (i.e., the anterior insula and the anterior cingulate cortex) are connected more efficiently to the rest of the brain (2017, “Intelligence”). Another brain region, the junction area between temporal and parietal cortex that has been related to the shielding of thoughts against irrelevant information, is less strongly connected to the rest of the brain network. “The different topological embedding of these regions into the brain network could make it easier for smarter persons to differentiate between important and irrelevant information – which would be advantageous for many cognitive challenges,” proposes Ulrike Basten, the study’s principle investigator.

In their current study, the researchers take into account that the brain is functionally organized into modules. “This is similar to a social network which consists of multiple sub-networks (e.g., families or circles of friends). Within these sub-networks or modules, the members of one family are more strongly interconnected than they are with people from other families or circles of friends. Our brain is functionally organized in a very similar way: There are sub-networks of brain regions – modules – that are more strongly interconnected among themselves while they have weaker connections to brain regions from other modules. In our study, we examined whether the role of specific brain regions for communication within and among brain modules varies with individual differences in intelligence, i.e., whether a specific brain region supports the information exchange within their own ‘family’ more than information exchange with other ‘families’, and how this relates to individual differences in intelligence.”

The study shows that in more intelligent persons certain brain regions are clearly more strongly involved in the exchange of information between different sub-networks of the brain in order for important information to be communicated quickly and efficiently. On the other hand, the research team also identified brain regions that are more strongly ‘de-coupled’ from the rest of the network in more intelligent people. This may result in better protection against distracting and irrelevant inputs. “We assume that network properties we have found in more intelligent persons help us to focus mentally and to ignore or suppress irrelevant, potentially distracting inputs,” says Basten. The causes of these associations remain an open question at present. “It is possible that due to their biological predispositions, some individuals develop brain networks that favor intelligent behaviors or more challenging cognitive tasks. However, it is equally as likely that the frequent use of the brain for cognitively challenging tasks may positively influence the development of brain networks. Given what we currently know about intelligence, an interplay of both processes seems most likely.”

UNC School of Medicine neuroscientists discover a long-distance brain circuit that controls the production of new neurons in the hippocampus. Research could have implications for understanding and treating many brain disorders, including epilepsy, schizophrenia, depression, and Alzheimer’s disease

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Reported as the cover story in Cell Stem Cell, the researchers identified a neurogenesis-controlling brain circuit that runs from near the front of the brain back to the hippocampus, a learning- and memory-related structure. The hippocampus is one of the major sites of neurogenesis in the adult human brain, and the circuit that Song’s team has identified regulates this neuron-producing process.

“This circuit controls the activity of stem cells in the part of the hippocampus where neurogenesis occurs,” said Song, a member of the UNC Neuroscience Center. “Our finding ultimately could have implications for understanding and treating many brain disorders arising from aberrant hippocampal neurogenesis, including epilepsy, schizophrenia, depression, and Alzheimer’s disease.”

Neural stem cells are like stem cells in other tissues and organs – they give birth, if needed, to new cells that replace dead or dying ones. Most of the neurons in the adult brain are wired tightly into complex circuits and are not replaced.

The chief exception is the dentate gyrus (DG) region of the hippocampus. Neurogenesis in the DG occurs throughout adult life and supports the hippocampus’s crucial functions in storing and retrieving memories. DG neurogenesis has been linked to mood as well. In fact, scientists suspect that the mood-improving effects of antidepressant drugs and physical exercise arise at least in part from the boost they give to DG neurogenesis.

It would seem logical to begin research on motivation by examining the thing that motivates—the end goal, the desired outcome, the carrot on the end of the stick. That’s what Dr. R. Alison Adcock, Assistant Professor of Psychiatry and Behavioral Sciences at Duke University, and her team have done in a series of studies examining how people respond to different rewards. But the results of their studies have been surprising, indicating more variation from person to person than her team expected:

“One of the things that has felt most productive from our work is evidence that rewards mean very different things to different people—and we can see that in how their brains respond.”

For example, when Adcock and her team offered study participants monetary rewards for completing a puzzle, some participants’ brains lit up in the pleasure center and other participants’ brains responded with what looked like anxiety or fear. Of the latter group, Adcock says, “Some people responded like we were threatening them with an electric shock when we promised them money for doing a maze.” For whatever reason—performance anxiety, fear of failure, lack of confidence—these people felt stressed instead of motivated when presented with the prospect of monetary rewards.

This means that examining external rewards may not be the best way to understand motivation after all. A better way, in fact, may be to look at what drives us when no visible external reward is present.