Mental Imagery “Visualization”

The strength of a person’s mental imagery is associated with excitability in the prefrontal cortex and visual cortex. Highly excitable neurons in the visual cortex may reduce a person’s ability to imagine mental images. The findings shed light on how visualizing mental images, may occur.

The strength of a person’s mental imagery – their ability to picture something in their mind’s eye – is linked to the excitability of different brain regions, a study led by researchers at UNSW Sydney has found.

Surprisingly, participants with less excitable visual cortex saw stronger mental images. Neurons that fire more frequently in the visual cortex could be adding ‘noise’ to the image signal, the researchers theorise – interfering with a person’s ability to form a clear image in their mind.

Think of the brain’s visual cortex as a chalkboard. Drawing a picture on a dusty (more excitable) chalkboard would make it hard to see, but if you draw on a cleaner (less excitable) chalkboard, the picture will be clearer.

After identifying a link between brain excitability and imagery strength, the researchers altered the excitability of a person’s visual cortex using a non-invasive brain stimulation (called Transcranial Direct Current Stimulation, or tDCS) to see whether it triggered a change to their imagery strength.

Manipulating brain excitability levels caused the image strength to change, suggesting that the link isn’t just correlative, but causative,” says Dr Keogh.

“This is an exciting development for using tDCS in potential imagery adjustment therapies.” Mental imagery plays an important role in fight sports mental processes. Whether remembering the past, reading books or in guided meditation, many people use visual imagery every day.

“Mental imagery is a keystone mental process,” says Prof Pearson. “It holds the key to unlocking our understanding of how we think, feel, remember and make decisions.”

Original Research:

Keogh, R., (2020). “Cortical excitability controls the strength of mental imagery”. eLife doi:10.7554/eLife.50232