Human eye - Temporal Summation | Britannica

human eye

Table of Contents

Introduction
Anatomy of the visual apparatus
- Structures auxiliary to the eye
  - The orbit
  - The eyelids
    - The conjunctiva
    - The fibrous layer
    - The muscles of the lids
    - The skin
  - The glandular apparatus
  - Extraocular muscles
- The eye
  - General description
  - Outer and middle tunics of the globe
    - The outermost coat
    - The uvea
  - The inner tunic of the globe
    - The epithelia
    - The retina
  - The transparent media
    - The aqueous humour
    - The vitreous body
    - The crystalline lens
The visual process
- The work of the auxiliary structures
  - The protective mechanisms
    - Innervation
    - Blink reflexes
    - Normal rhythm
    - Secretion of tears
  - Movements of the eyes
    - The axes of the eye
    - Actions of muscles
    - Binocular movements
    - Nervous control
    - Reflex pathways
    - Voluntary centre
    - The nature of eye movements
    - Vision suppression during a saccade
- The work of the optical lens system
  - Refraction by cornea and lens
  - Normal sightedness and near- and farsightedness
  - Accommodation
    - Effects of accommodation
    - Mechanism of accommodation
    - Nerve action
  - The pupil
  - The near response
The work of the retina
- Some basic facts of vision
  - Measurement of the threshold
  - Scotopic sensitivity curve
  - Loss of dark adaptation
  - Bleaching of rhodopsin
- Synaptic organization of the retina
  - Plexiform layers
  - Convergence of the messages
- Absolute threshold and minimum stimulus for vision
  - Quantum fluctuations
  - Spatial summation
  - Temporal summation
- Inhibition
- Flicker
- Visual acuity
  - Measurement
  - Anatomical basis: the retinal mosaic
  - The retinal image
- Electrophysiology of the retina
  - Neurological basis
  - Anatomical basis
  - Direction-sensitive ganglion cells
  - The electroretinogram
  - Flicker
  - Visual acuity
- Colour vision
  - Spectral sensitivity curve
  - Colour mixing
  - Colour defectiveness
  - Responses of uniform population of photoreceptors
  - Young-Helmholtz theory
  - The nervous messages
  - Lateral geniculate cells
- The photochemical process
  - Rhodopsin
  - The transduction process
  - Cone pigments
The higher visual centres
- The visual pathway
  - Fusion of retinal images
  - The visual field
  - Lateral geniculate body
  - Striate area
  - Pupillary pathways
  - Point-to-point representation
  - Visuopsychic or circumstriate areas
- Integration of the retinal halves
  - Corpus callosum
  - Stereopsis in the midline
  - Callosal transfer
  - Superior colliculi
Some perceptual aspects of vision
- Projection of the retina
  - Relative positions of objects
  - Position in relation to observer
- Visual estimates
  - The directions of lines
  - Comparison of lengths
  - Optical illusions
- The perception of depth
  - Monocular cues
  - Binocular vision
- Retinal rivalry
  - Ocular dominance
  - Binocular brightness sensation
Electrophysiology of the visual centres
- Ganglion cells
- Geniculate neurons
- Cortical neurons
  - Eye dominance
  - Cortical architecture
  - Complex neurons
- Stereoscopic vision

References & Edit History Related Topics

Images, Videos & Interactives

cross section of the human eye

human body systems interactive

structure of the retina

muscles of the right eye

visual pathways in the human brain

visual field of the human eye

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In temporal summation, two stimuli, each being too weak to excite, cause a sensation of light if presented in rapid succession on the same spot of the retina; thus, over a certain range of times, up to 0.1 second, the Bunsen-Roscoe law holds: namely, that the intensity of light multiplied by the time of exposure equals a constant. Thus it was found that within this time interval (up to 0.1 second), the total number of quanta required to excite vision was 130, irrespective of the manner in which these were supplied. Beyond this time, summation was still evident, but it ...(100 of 31643 words)

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