A REVIEW OF ELECTRICAL ACTIVITIES IN VISUAL PERCEPTION: THE TRAVAIL OF VISUAL ACUITY IN HUMAN AND ANIMALS
A REVIEW OF ELECTRICAL ACTIVITIES IN
VISUAL PERCEPTION: THE TRAVAIL OF VISUAL ACUITY IN HUMAN AND ANIMALS
1Pofwon,
P. Patrick, 2Yilleng, C. Godiya., 2Nendi, P. Gomos and 2Dabhim,
D. Dashi
Plateau State College of Agriculture,
Garkawa, Plateau State Nigeria.
2College
of Health Technology Zawan, Plateau State, Nigeria.
ABSTRACT
The
paper investigated the role of electrical activities in visual perception in
human and animals. This review highlighted the Absorption of zero and one
photon in visual perception, Measurement of visual acuity, Optical constraints
on visual perception, Photochemistry of Vision and colour vision, however Human ability to see
is strictly dependent on the electrical signals
generated within the body. Among the recommendations, physics, is an
umbrella of medicine and as such be made compulsory in all spheres of the
medical practice.
INTRODUCTION
The
retina contains light transduction elements called photoreceptors which are the
rods and the cones. Their names depict their morphology Arden and Hogg (1992)
The
discs in the photoreceptors contain light sensitive chemical and these discs
store a large concentration of Ca++, the light incident on the eye
meet the photoreceptors from behind. The absorption of light energy by these
discs causes a change in structure of the receptors but not a change in shape.
The absorption of light by the Ca++ block and the Na+
release into the nerves leads to an inhibitory action of the light when it
falls on the retina. This is a process of hyperpotamation of the nerves due to
the light-absorption. The transmitter released by the photoreceptor is
suppressed by hyperpotances, the second order neurons. By this process the
light signal is signaled to the second order retinal neurons and from there to
the visual cortex, hence depolarization of the rods in the Clark Arden and Hogg (1992)
In short in visual perception, light
energy hv is converted to electrical energy by the process of hyperpolarization
by the photoreceptors.
Absorption of zero and one photon in
visual perception
The detection is assumed to be a noise
free event and the distribution of photon in the test pulse is given by the poison
distribution:




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