Scientists have labored for decades to understand how brain structure and functional connectivity drive intelligence. A new analysis offers the clearest picture yet of how various brain regions and neural networks contribute to a person’s problem-solving ability in a variety of contexts, a trait known as general intelligence, researchers report.

They detail their findings in the journal Human Brain Mapping.

Researchers studied the effects of a 12-week exercise regimen on 148 active-duty Air Force airmen, half of whom also received a twice-daily nutrient beverage that included protein; the omega-3 fatty acid, DHA; lutein; phospholipids; vitamin D; B vitamins and other micronutrients; along with a muscle-promoting compound known as HMB. Both groups improved in physical and cognitive function, with added gains among those who regularly consumed the nutritional beverage, the team reports.

People with specific brain attributes are more likely than others to benefit from targeted cognitive interventions designed to enhance fluid intelligence, scientists report in a new study. Fluid intelligence is a measure of one’s ability to adapt to new situations and solve never-before-seen problems.

A new study links higher levels of several key nutrients in the blood with more efficient brain connectivity and performance on cognitive tests in older adults.

The study, reported in the journal NeuroImage, looked at 32 key nutrients in the Mediterranean diet, which previous research has shown is associated with better brain function in aging. It included 116 healthy adults 65-75 years of age.

Small sample sizes in studies using functional MRI to investigate brain connectivity and function are common in neuroscience, despite years of warnings that such studies likely lack sufficient statistical power. A new analysis reveals that task-based fMRI experiments involving typical sample sizes of about 30 participants are only modestly replicable. This means that independent efforts to repeat the experiments are as likely to challenge as to confirm the original results.

Centuries of study have yielded many theories about how the brain gives rise to human intelligence. Some neuroscientists think intelligence springs from a single region or neural network. Others argue that metabolism or the efficiency with which brain cells make use of essential resources are key.

A new theory, published in the journal Trends in Cognitive Sciences, makes the case that the brain’s dynamic properties – how it is wired but also how that wiring shifts in response to changing intellectual demands – are the best predictors of intelligence in the human brain.