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The interaural time difference (ITD) can be used by barn owls to help determine the location of prey. What information is determined from the ITD? How does the Jeffers’s model suggest this information is encoded? Interaural time difference is when the sound comes from anywhere but infront of the owl and arrives at the two ears at slightly different timings. ITD consists of transiet disparity and ongoing disparity. Transient disparity is the difference of the onset and offset of sound whereas the ongoing disparity is the difference between the ears of continuously heard sound. Ongoing disparity is used to determine azimuth, meaning it is responsible for the horizontal localisation of sound. The inferior Colliculus is the part of the auditory system which receives the input of sound, it has space specific cells which are binaural and contain inhibitory and excitatory regions. The ITD’s is determined by time getting processed from the cranial nerve to the nucleus magnocellularis to the nucleus laminaris and finishes at the inferior colliculis. Jeffers asked the question: ‘How does a neuron receive input from 2 ears when they receive it a delay in one ear relative to another?” Jeffers model for encoding LTD’s had two features:  Delay lines  Coincidence Detectors Jeffers suggested that there is a delay line at the side the input is coming from. The delay line then allows for the opposite side to “play catch up” as it receives the sound input, meaning they both hit the coincidence detectors at the same time, allowing for maximum output. This is what allows for the owl localise prey horizontaly as the coincidence detector which is activated by both inputs at the same time can determine where the stimulus is. In the barn owl the nucleus laminaris may be the anatomical substrate for Jeffers model . This is because the Nucleus Laminaris would act as coincidence Detectors with ipsilateral and contralateral axons from the Nucleus magnocellularis, acting as they delay lines. These then all project to the inferior colliculus, which interprets which neuron is firing and corresponds to a particular ITD, hence allowing the barn owl to localise its prey along its horizontal axis....