Feeling without seeing

1993/04/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

The mole usually does not see it, but if it has two small eyes the physiologist yells at them. If you don't see it, why do you have it?

Spalax erhenberghi mole has preserved in its evolution of 25 or 30 million years the imprint of something of the visual organ. It has two microscopic eyes with a maximum diameter of 700 microns (the eye of rodents of the same size has a diameter of approximately 6 mm). In addition, these eyes are covered by a skin and light has to pass through it if you want to reach the retina. Of course, there were reasons to say that the mole was blind.

Howard M. However, researchers Cooper, Marc Herbin and Eviatar Nevo have made an interesting discovery. This mole is able to detect changes in light intensity. By feeling “photoperiodic” cycles, it regulates its daily activity and biological rhythms. This is absolutely necessary, especially to maintain your thermal balance. Cold resistance depends on the duration of the day. The shorter the day, the greater the cold resistance.

But how does it detect and transmit light to the brain? It has been observed that, using marking techniques, it has few retinal cells (100 times less than normal rodents of the same size), but not all visual structures have been degenerated or degenerated at the same level. The structure of form analysis, motion detection, and visual coordination with motor motor has significantly receded, but the structures of the hypothalamus and edge of stretch marks related to photoperiodic functions have twenty times more developed than conventional rodents.

These structures have much to do with the hormonal cycle, reproduction and other physiological rhythms.

These results affect medicine and can clarify the mechanisms of delayed human vision (microphotography).