Mental Health

How Imagination Works In The Human Brain: Creative Thinking Allows Neurons To Work Together To Assemble Mental Images

Books, movies, and Broadway shows allow us to process audio and visual information through the brain. The mind starts to imagine how the book character is dressed; how the movie could end; or what's the show's plot twist? Our imagination begins to wonder, but how exactly could we produce an image, or think about something we've never seen?

In TED-Ed's video, "The Neuroscience Of Imagination," Neuroscientist Dr. Andrey Vyshedskiy, explains our ability to imagine things instantly is a complex problem that requires precise coordination inside the brain. We're able to create new, weird images, as the brain takes familiar pieces and assembles them in new ways, similar to how a collage is made from fragments of photos. This prompts the brain to juggle a series of electrical signals to get them all to their destination at the exact same time.

Read: Scientists Now Understand How Imagination Works

Thousands of neurons fire in our posterior cortex when we look at an object. These neurons encode various characteristics of the object, for example, a pineapple's skin is processed to be spiky, and its fruit yellow. This synchronous firing strengthens the connections between the set of neurons, putting them together in what's known as a neuronal ensemble, known as the Hebbian principle. This means neurons that fire together, wire together.

When we try to imagine a pineapple later, the whole ensemble will light up, forming a complete mental image. Meanwhile, imagining a dolphin will be encoded by a different neuronal ensemble. Now, we may try to imagine a dolphin balancing a pineapple, but why are we able to do so, if this doesn't exist?

Mental synthesis.

The theory of mental synthesis is all about timing. If the neuronal ensemble for the dolphin and pineapple are activated at the same time, we can perceive the two separate objects as a single image. However, something in the brain has to coordinate that firing. It's hypothesized the prefrontal cortex - involved in all complex cognitive functions - could be behind neuronal firing.

Prefrontal cortex neurons are connected to the posterior cortex by long, spindly cell extensions called neural fibers. The mental synthesis theory proposes the prefrontal cortex neurons send electrical signals down these neural fibers to multiple ensembles in the posterior cortex, which activates them in unison.

If the neuronal ensembles are turned on at the same time, you experience the composite image just as if you'd actually seen it. This is why we're easily able to imagine a dolphin balancing a pineapple. In order for mental synthesis to work, signals would have to arrive at both neuronal ensembles at the same time. However, some neurons are much farther away from the prefrontal cortex than others. If the signals travel down both fibers at the same rate, they'd arrive out of sync.

We can't change the length of the connections, but the brain has a way to change the conduction of velocity. Neural fibers are wrapped in a fatty substance called myelin, an insulator that speeds up the electrical signals zipping down the nerve fiber. Some neural fibers have as many as 100 layers of myelin, while others only have a few. Fibers with thick layers of myelin can conduct signals 100 times faster than those with thinner layers.

Read: Imagination And Memory Both Access The Hippocampus

Some scientists believe this difference in myelination could be the key to uniform conduction time in the brain, and consequently our mental synthesis ability.

It seems science still has not caught up as to why our imagination runs wild sometimes.

See Also:

How Imagination Influences BMI

Imagination And Reality Flow In Opposite Directions In The Brain