Danish scientists first described the case of temporary changes in colour perception immediately after electroconvulsive therapy. The patient, who had been in therapy for the treatment of postpartum depression, at the time the symptoms of color blindness: she began to distinguish between red and green. About the case briefly told in a letter to the editor, published in the journal Brain Stimulation.
For color perception in the human eye respond with “daytime” (i.e. reacting to a bright light) photoreceptors coloccini forms (they are, therefore, called cones), which are filled with light-sensitive pigment of iodopsin. Iodopsin, in turn, is of three types — each of them is responsible for sensing light with short, long or medium wavelength.
For correct color perception of the cone needs to be a balance, and its violation indicates the presence of color blindness — that is, violation of perception of light with a certain wavelength. The patient’s psychiatric center Copenhagen, which was observed by the Christian Jensen (Kristian Jensen) and his colleagues was the most common form of color blindness — deuteranopia: it disturbed perception of red and green or both together.
Electroconvulsive therapy (ECT) the patient was prescribed as a treatment for postpartum depression after she helped classic treatment Syssin, and the condition worsened (the researchers noted that the patient was hospitalized, and she was prescribed antipsychotic drugs). ECT is classically performed under General anesthesia: current with a frequency of 30-70 Hz were performed using electrodes located at both temples, for 6-8 seconds.
The researchers reported that immediately after the ECT sessions, the patient reported improved colour perception: for example, a woman told me that could distinguish the red berries among the green leaves in the picture, as well as individual colors painted on her watercolors. Overall, in the perception of the patient within a few hours the color had become “brighter and richer”. The effect was temporary: in the morning after a session of ECT color perception returned to normal for the patient.
Before the next (23 in a row) session the patient gave 38 cards Ishihara — they are classically used to determine color blindness. Patient had made 30 errors. An hour after ECT, the researchers again gave the patient card and this time she made a mistake by only 15 times, again saying that all colors become brighter.
The researchers noted that they could not find earlier mention improve vision after ECT or other stimulation. It is unlikely, according to them, stimulation affected the concentration of iodopsin in cones and their number: it is obvious that changes have occurred at a different level, most likely in the thalamus or parts of the cerebral cortex responsible for color processing. It is also interesting that other aspects of vision were not affected: the patient did not report any changes in depth perception, no shapes, no faces and other images.
Due to the fact that the patient is also informed about changes in your well-being and improved mood immediately after the therapy, the researchers also compared the effect with the effect of another rare and more experimental treatment of depression — ingestion of psychedelics, which also affects the perception and can temporarily improve the perception.
In General, targeted stimulation can enable us to see colors where they shouldn’t be. For example, in 2017, the scientists showed that the patient with epilepsy and the fusiform gyrus: depending on place of stimulation, he saw an empty space or a rainbow, or a person.