NSCI 110 1st Edition Lecture 24 Outline of Last Lecture I. Sound waves consist of compressed air and rarefied air particlesa. Frequency is the number of cycles per second (pitch)b. Amplitude is the height of the wave (loudness)II. Threshold is the minimum frequency at which a sound can be heard 50% of the timea. Amount of energy needed to hear very low frequency sounds is highIII. Basic anatomy of the human eara. Outer, middle, inner earb. The cochlea has three different chambers, including the Organ of Cortii. Basilar membrane moves in response to sound vibrations and causes hair cells to move and relay action potentials to the cortexOutline of Current Lecture I. The auditory system also exhibits tonotopic organizationII. Information from the ears travels both to the ipsilateral and contralateral sides of the cortexIII. The Wernicke-Geschwind model examines normal versus deficient language processingCurrent Lecture- Only selected bipolar cells are activated by hair cells that are moved by the basilar membraneo Allows for tonotopic organization (select set of bipolar cells leads to select pathways resulting in processing in the auditory cortex)o 5th order 5 separate sets of neurons relaying auditory information- 2/3 of the information travels to the contralateral side of the cortexo 1/3 travels to the ipsilateral side- There is a delay in time between sound waves hitting one ear from side vs the opposite earo Superior olive nucleus compares the lateralization of soundso Inferior colliculus adds to spatial analysis and also detects intensity of sounds Differences in both these aspects allows orientation to the stimuli “Sound shadow” on contralateral ear- Wernicke-Geschwind Model (based on brain injury)o Wernicke’s area gives us an “auditory image” by converting action potentials into languageThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Signal sent from axons of the arcuate fasiculus to Broca’s area to generatespeech This pathway travels along the inner wall of the insula (perpendicular to the lateral fissure)- Basic mechanisms of languageo Wernicke-Geschwind model examines deficits vs normal functioning Hear sound, decipher it, convert to auditory image, process in Wernicke’s area, put meaning to the words comprehension involves this simple pathwayo More complicated pathway Thought (cognitive operation) Wernicke’s area Broca’s area facialarea of motor cortex cranial nerves speecho Reading Written word visual cortex angular gyrus Wernicke’s area
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