August 2nd, 2004 Doog left the tests in his office. Silly Doog... He found em'. And there was much rejoicing. Test reviewage... Test Questionage... Comments... Done an experiment? scraig@memphis.edu (remember the confirmation) ____________________________________________________________________________ Short lecture today... Short Memory There are other classifications for memory... Explicit and Implicit. - Explicit this is typified by the ability to explain what you're doing. - Implicit usually typified by procedure. We haven't gone very far into the nature or function of the hippocampus... Let's look at a cellular mechanism that might support long term memory. This work came out in 1973. One of the most studied cellular phenomena. Long term potentiation. LTP Often studied in the hippocampus becuase its easiest to see it here. (however it works everywhere.) If you take a brain and cut it straight down the center. Its called the coronal cut. The hippocampus will look like two interlocking Cs. The Cortext would be above it and the F/F would be coming from the left. CA1 - CA4 Structures in the Hippo. Were gonna talk about CA1 and CA3 which are the most distinctive brain regionas in the Hippo. CA1 is the upper area in the top crest of the top interlocking C. CA3 is at the polar opposite of that in the trough area of the bottom interlocking C. CA3 projects to CA1. (Called the Schaffer Colaterals.) It is an excitatory projection. When CA3 is active so is CA1. Etc... Amount of Cellular Activity in CA1. As active as they can get (Seizuring) I I I _ I / \ I / \ _This effect is potentiated in comparison I This is Stim of CA3 \ / \ to the other small stim before the I _ _ / \ / \ large stim. And is very long term I / \ / \ / \ / \ in terms of neural activity. I / \ / \ / \ / \ I----------------------------------------------- (This is our Base Line) I Nothing is done to system. I_______________________________________________ 0 i i I i Time. Lots (NO ACTIVITY IN CELL) i = little stimulus in CA3 I = large stim of CA3 You count Neural activity by placing something that Neurons can interact with in close proximity that will measure voltage spikes. Doug gives a Miss America wave... (no idea why) Doug hurt his wrist moving. (Its very sad) If we stimulate CA3 it will drive CA1 so we are doing that with a probe. Orthadromic Experiment. (Thats what this experiment is called) So in this experiment they are driving CA3 very hard (lots of current) and trying to exhibit memory in cells. This is considered a cellular type of memory. There is also a depression which is the opposite of the stim in the graph however much less is known about it.