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The parietal eye (very small grey oval between the regular eyes) of a juvenile bullfrog (Lithobates catesbeianus) Adult green anole (Anolis carolinensis) clearly showing the parietal eye (small grey/clear oval) at the top of its head Parietal eye of the Merrem's Madagascar swift (Oplurus cyclurus) is surrounded by a black-and-white spot on the skin, giving it the "three-eyed" appearance
They even identified what they called "bug detectors", or cells in a frog's retina that are predisposed to respond when small, dark objects enter the visual field, stop, and then move intermittently. In short, Lettvin’s group discovered that a lot of what was thought to happen in the brain actually happened in the eye itself.
Frogs have a highly developed nervous system that consists of a brain, spinal cord and nerves. Many parts of frog brains correspond with those of humans. It consists of two olfactory lobes, two cerebral hemispheres, a pineal body, two optic lobes, a cerebellum and a medulla oblongata.
Not all animals have neurons; Trichoplax and sponges lack nerve cells altogether. Neurons may be packed to form structures such as the brain of vertebrates or the neural ganglions of insects. The number of neurons and their relative abundance in different parts of the brain is a determinant of neural function and, consequently, of behavior.
The arachnoid mater covering the brain is referred to as the arachnoidea encephali, and the portion covering the spinal cord as the arachnoidea spinalis. The arachnoid and pia mater are sometimes considered as a single structure, the leptomeninx, or the plural version, leptomeninges ( lepto , from the Greek root meaning "thin" or "slender").
Dissection of a frog. Pain is an aversive sensation and feeling associated with actual, or potential, tissue damage. [1] It is widely accepted by a broad spectrum of scientists and philosophers that non-human animals can perceive pain, including pain in amphibians.
The skull of the ancient amphibian, measuring just over an inch (about 2.5 centimeters) long, features big oval eye sockets and — due to its slightly crushed state — a lopsided smile that ...
One of the most influential early contributions was a 1959 paper titled What the frog's eye tells the frog's brain: the paper examined the visual responses of neurons in the retina and optic tectum of frogs, and came to the conclusion that some neurons in the tectum of the frog are wired to combine elementary responses in a way that makes them ...