temporal summation

Examples of temporal summation in the following topics:

• Signal Summation

  • Signal summation occurs when impulses add together to reach the threshold of excitation to fire a neuron.
  • Summation, either spatial or temporal, is the addition of these impulses at the axon hillock .
  • Together, synaptic summation and the threshold for excitation act as a filter so that random "noise" in the system is not transmitted as important information.
  • Spatial summation means that the effects of impulses received at different places on the neuron add up so that the neuron may fire when such impulses are received simultaneously, even if each impulse on its own would not be sufficient to cause firing.
  • Temporal summation means that the effects of impulses received at the same place can add up if the impulses are received in close temporal succession.

• Evolution of Amniotes

  • The key differences between the synapsids, anapsids, and diapsids are the structures of the skull and the number of temporal fenestrae behind each eye .
  • Temporal fenestrae are post-orbital openings in the skull that allow muscles to expand and lengthen.
  • Anapsids have no temporal fenestrae, synapsids have one, and diapsids have two.
  • The image illustrates the differences in the skulls and temporal fenestrae of anapsids, synapsids, and diapsids.

• Brain: Cerebral Cortex and Brain Lobes

  • The cerebral cortex of the brain is divided into four lobes responsible for distinct functions: frontal, parietal, temporal, and occipital.
  • Each hemisphere of the mammalian cerebral cortex can be broken down into four functionally- and spatially-defined lobes: frontal, parietal, temporal, and occipital .
  • The temporal lobe is located at the base of the brain by the ears.
  • The human cerebral cortex includes the frontal, parietal, temporal, and occipital lobes, each of which is involved in a different higher function.

• CAM and C4 Photosynthesis

  • In contrast to C4 metabolism, which physically separates the CO2 fixation to PEP from the Calvin cycle, CAM temporally separates these two processes.
  • CAM concentrates it temporally, providing CO2 during the day and not at night, when respiration is the dominant reaction.

• Reproductive Isolation

  • Differences in breeding schedules, called temporal isolation, can act as a form of reproductive isolation.
  • These two related frog species exhibit temporal reproductive isolation.

• Visual Processing

  • A second stream projects to the temporal lobe and carries both magnocellular ("where") and parvocellular ("what") information.

• Human Axial Skeleton

  • The eight cranial bones include the frontal bone, two parietal bones, two temporal bones, the occipital bone, the sphenoid bone, and the ethmoid bone.
  • The cranial bones, including the frontal, parietal, temporal, occipital, ethmoid, and sphenoid bones.

• Homo sapiens

  • Humans are distinguished from other primates by their bipedal locomotion and by their relatively larger brain with its particularly well-developed neocortex, prefrontal cortex, and temporal lobes, which enable high levels of abstract reasoning, language, problem solving, and culture through social learning.

• Transduction of Sound

  • The afferent, bipolar neurons that convey auditory information travel from the cochlea to the medulla, through the pons and midbrain in the brainstem, finally reaching the primary auditory cortex in the temporal lobe.
  • The inner ear can be divided into three parts: the semicircular canals, the vestibule, and the cochlea, all of which are located in the temporal bone.

• The Vestibular System

  • There are also projections to the temporal cortex, which account for feelings of dizziness; projections to autonomic nervous system areas in the brainstem, which account for motion sickness; and projections to the primary somatosensory cortex, which monitors subjective measurements of the external world and self-movement.