PHGY 209 Lecture Notes - Lecture 9: White Matter, Posterior Grey Column, Lamellar Corpuscle
17 Mar 2017
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Perception of the external world: sensation: conscious awareness of sensory information/stimulation, perception: the understanding of a sensation"s meaning. Ex: feeling pain = sensation; awareness that tooth hurts = perception. We don"t perceive the energy of a sensory stimulus directly. We only perceive the neural activity that is produced by sensory stimulation: law of specific nerve energies: Regardless how a sensor receptor is activated, sensation felt = that receptor"s specialization. Ex: rub eyes hard & you"ll see light: law of projection: Regardless where in brain you stimulate a sensory pathway, sensation is. Process: stimulus energy received by receptor membrane/receptor cells, adequate stimulus: type of stimulus a particular receptor will normally respond to due to it"s transduction mechanisms/ion channels, transduction occurs: Important: magnitude of ap doesn"t change, only frequency. **as long as receptor potential keeps afferent neuron depolarized above threshold ap continue to propagate down neurons**
