Content of Thought

Imagination : Content of Thought

One reason we can change our brains simply by imagining is that, from a neuroscientific point of view, imagining an act and doing it are not as different as they sound. When people close their eyes and visualize a simple object, such as the letter “a”, the primary visual cortex lights up, just as it would if the subjects were actually looking at the letter “a”. Brain scans show that in action and imagination many of the same parts of the brain are activated. That is why visualizing can improve performance. 

In an experiment that is as hard to believe as it is simple, Drs. Guang Yue and Kelly Cole showed that imagining one is using one's muscles actually strengthens them. The study looked at two groups, one that did physical exercise and one that imagined doing exercise. Both groups exercised a finger muscle, Monday through Friday, for four weeks. The physical group did trials of fifteen maximal contractions, with a twenty-second rest between each. The mental group merely imagined doing fifteen maximal contractions, with a twenty-second rest between each, while also imagining a voice shouting at them, “Harder! Harder! Harder!”

At the end of the study the subjects who had done physical exercise increased their muscular strength by 30 percent, as one might expect. Those who only imagined doing the exercise, for the same period, increased their muscle strength by 22 percent. The explanation lies in the motor neurons of the brain that “program” movements. During these imaginary contractions, the neurons responsible for stringing together sequences of instructions for movements are activated and strengthened, resulting in increased strength when the muscle are contracted.

The research has led to the development of the first machines that actually “read” people's thoughts. Thought translation machines tap into motor programs in a person or animal imagining an act, decode the distinctive electrical signature of the thought, and broadcast an electrical command to a device that puts the thought into action. These machines work because the brain is plastic and physically changes its state and structure as we think, in ways that can be tracked by electronic measurements.

Experiments show how truly integrated imagination and action ar, despite the fact that we tend to think of imagination and action as completely different and subject to different rules. Illustration by Elena.

These devices are currently being developed to permit people who are completely paralyzed to move objects with their thoughts. As the machines become more sophisticated, they may be developed into thought readers, which recognize and translate the content of a thought, and have the potential to be far more probing than lie detectors, which can only detect stress levels when a person is lying. 

These machines were developed in a few simple steps. In the mid-1990s, at Duke University, Miguel Nicolelis and John Chapin began a behavioral experiment, with the goal of learning to read an animal's thoughts. They trained a rat to press a bar, electronically attached to a water-releasing mechanism. Each time the rat pressed the bar, the mechanism released a drop of water for the rat to drink. The rat had a small part of its skull removed, and a small group of micro-electrodes were attached to its motor cortex. These electrodes recorded the activity of forty-six neurons in the motor cortex involved in planning and programming movements, neurons that normally send instructions down the spinal cord to the muscles. Since the goal of the experiment was to register thoughts, which are complex, the forty-six neurons had to be measured simultaneously. Each time the rat moved the bar, Nicolelis and Chapin recorded the firing of its forty-six motor-programming neurons, and the signals were sent to a small computer. Soon the computer “recognized” the firing pattern for bar pressing.

After the rat became used to pressing the bar, Nicolelis and Chapin disconnected the bar from the water release. Now when the rat pressed the bar, no water came. Frustrated, it pressed the bar a number of times, but to no avail. Next the researchers connected the water release to the computer that was connected to the rat's neurons. In theory, now, each time the rat had the thought “press the bar,” the computer would recognize the neuronal firing pattern and send a signal to the water release to dispense a drop.

After a few hours, the rat realized it didn't have to touch the bar to get water. All it had to do was to imagine its paw pressing the bar, and water would come. Nicolelis and Chapin trained four rats to perform the task.

(Imagination. The Brain That Changes Itself by Norman Doidge, M.D., excerpt).

If the brain is easily altered, how are we protected from endless change? Photograph by Elena.