[Music] auditory cortex so you'll recall we have our image in the lower left corner here's our semicircular canals here's our CA right next door and we have this vestibular cular nerve coming in here seven and eight going through the internal acoustic meatus all those good things focusing on the CIA I think of this as a backward piano keyboard because this has basically a tonotopically organized um organization to it and um this information at a tonotopic level is going to go through this auditory nerve through that vestibular clear nerve into our a clear nuclei and from there it's going to bounce around through half a dozen brain stem areas work its way up through the inferior calculus go out that brachium of the inferior calculus out to the medial geniculate body remember medial for music mgn and from the medial geniculate to auditory cortex and if you take your boxing glove you make your fist and open that thumb you're looking inside the Sylvan Fisher or that lateral sulcus and then that posterior aspect is a transverse temporal gyrus and that's where your primary auditory cortex is hanging out so here's a primary auditory cortex and you can use functional MRI to map that out so here are eight people from my lab where we mapped out uh to a topic High to medium to low pitches and on average here's where the primary auditory cortex is located and you can map out areas sensitive to vocalization shown in the blue and then s uh areas that are sensitive to speech uh Native speech for English speakers in this case and these areas more in the pink uh become more sensitive when you hear speech related sounds so the point of this slide is that as you go from the early tonotopically organized auditory areas to more complex stimuli such as vocalizations and speech sounds you're going out more laterally uh and spreading out along the cortical mantle as these more higher association areas put together what is that sound information put together words for you and other acoustic objects now if you have um oh and here's a uh to go with Dr Jan's talk here we have a DTI image looking some of that tractography going from the medial geniculate nucleus out to uh transverse tempal gyrus with the fusion tensor Imaging shown here if you have alion to one of your primary auditory cortex may have some difficulty uh localizing sound subtle hearing loss but usually not terribly terribly bad you really need to take out both the left and right hemisphere uh and if you do that then you lose conscious level perception of what you're hearing now if it's just the cortex that you're taking out you still have acoustic reflexes intact so if you here's something and jump and respond to that that's going through that inferior calculus and brain stem structures and those are can be still relatively intact but you're not consciously aware of what you're are hearing then auditory Association cores we get to the superior temporal gyrus and Superior temporal sulcus region and when you have damage there that can lead to what's called Central hearing loss so you might be able to hear that there's a sound but you have difficulty putting it putting it together what are you hearing and that ties in with what Dr ton was talking about with uh vernik area if it's a left hemisphere damage uh and this would be a vernes area where right is on the let's see right is on the left side of the screen it's radiologic format uh and if that's affecting your vernes area or your language reception areas then you have difficulty putting words together you can hear someone's talking but you can't tell what they're saying it's kind of like Charlie Brown the adults when they hear the wall w i could tell you're talking but I don't know what you're saying hey everyone Ryan rad here from neurosurgery trining dorg if you like that video subscribe and donate to keep our content available for medical students across the world