The functional area of the brain that is located within the precentral gyrus is the primary motor cortex, which is also known as the motor strip or Brodmann area 4.
The primary motor cortex or Brodmann area 4,is responsible for planning as well as controlling and executing voluntary movements and skeletal muscles.
In order to control these muscles, your cortex is organized somatotopically, which is often illustrated as the motor homunculus, in which specific strips of tissue correspond to specific, opposite contralateral parts of your body.
Brain wrinkles also do correlate to intelligence, but not in the simple way of having more wrinkles always meaning high IQ.
The brain's wrinkles or folds allow your brain to vastly increase it's surface area, which means that more neurons can be packed into the restricted space of your skull.
The outer layer of the brain, or the cerebral cortex is where most of the information processing happens.
And folding or wrinkling increases the surface area, which allows for greater brain processing power.
And research also shows that the depth of even very small, specific folds of the brain called tertiary sulci also correlates with better reasoning skills and deeper grooves reduce the physical distance that neural signals have to travel, which allows different brain regions to communicate more efficiently.
Although, it's not a hard rule as you cannot simply look at a single brain and predict someone's exact IQ based solely on how wrinkly the brain is.
Also too many wrinkles or folds in the brain can also actually be harmful.
In medical conditions like polymicrogyria, having excessive brain folding does not lead to higher intelligence, and instead it disrupts the normal brain wiring and can result in intellectual disabilities or epilepsy.
The age at which your brain is the sharpest is often between the ages of 18 and 19.
Although it's said that your brain is not fully developed until around 25 years of age.
However, there's not an actual single age when the brain is at it's sharpest as it can vary from person to person, and there's different cognitive abilities that peak at vastly different times across the persons lifespan.
Your brain's processing speed peaks in your late teens or between the ages of 18 to 19 years of age, after which the raw processing speed declines gradually.
Your short term memory and face recognition, in which your memory capacity peaks around the age of 25 and remains steady until around age 35.
Your ability to recognize faces peaks around age 32.
And your concentration and focus and attention span improve as you age, often peaking around age 43.
Your emotional and social intelligence, and your ability to accurately read other people's emotions peaks in your 40s to 50s.
And your knowledge and your vocabulary, which includes your crystalized intelligence (accumulated faces, wisdom and vocabulary) also peaks much later, often in your late 60s to 70s.
And as a result of these trade offs, it's suggested that your overall capacity, which is your blend of experience, judgement and your emotional regulation, actually hits it's highest point in your late midlife of between ages 55 to 60.
Although while the brain is said to be fully developed by age 25, the brain is still developing after that.
The idea that your brain suddenly finishes developing and hit's it's fully maturity at exactly age 25 is a pervasive oversimplification.
Although the major developmental changes, most particularly in your prefrontal cortex are prominent during your 20s, it's been shown in neuroscience that your brain still continues to grow, develop and reorganize and refine it's network efficiency well into your early 30s.
The age 25 milestone of a brain being fully developed originates from earlier MRI studies, which looked at your brain structure changes but also stopped testing around age 20.
Because the data plateaued in that timeframe, scientists also hypothesized that development wrapped up in a persons mid 20s.