Class Notes (834,339)
Canada (508,495)
Psychology (397)
PSYO 2470 (35)
Lecture 18

PSYO 2470 Lecture 18: Memory II
Premium

7 Pages
24 Views
Unlock Document

Department
Psychology
Course
PSYO 2470
Professor
Stamp Jennifer
Semester
Winter

Description
Memory II Information processing in MTL - - Hippocampus doesn’t receive info directly from striate cortex o A lot of processing before the cortex ▪ Association areas, then to parahippocampal and rhinal cortical areas, finally reaching hippocampus • Feedback mechanisms important for reconsolidation • Connections from hippocampus by fornix to thalamus and hypothalamus that can add emotion context - Hippocampus thought to be seat of epileptic convulsions o Stimulate hippocampus and associated areas when showing images of the same character ▪ Fires action potentials with images of a character as well as images associated with that character as well as that character’s name • Information going to hippocampus is highly processed Patient HM findings published by Milner and Scoville - HM o Sustained head trauma very young ▪ Began getting seizures later on – seizures became almost incapacitating • Doctors tied hippocampus to seizures – removed hippocampus from both left and right hemisphere as well as parts of other structures including amygdala o Was no longer able to form new long term memories – anterior grade amnesia ▪ Had some things he could remember, and some he could not • Working memory remained in tact o Suggested hippocampus was crucial for long term memory formation, which required consolidation • Difficulty with episodic and declarative memory • Procedural memory remained in tact o Still had ability to develop new motor skills ▪ Appearing independent of medial temporal lobe ▪ Shows improvement of skills he learned earlier – got better at skills he didn’t remember already learning how to do • Not all memory stored in the same area o Brenda Milner and HM ▪ Milner spent 30 years working with HM after the surgery – he doesn’t remember her Testing declarative memory in animals - Also called explicit memory o Able to declare memories – done to show evidence the memories exist - Episodic memory o Memory of episodes and events ▪ Tied to time and place o Memory most effected by damage and stroke - Looking at ability for an animal to keep something in their mind o Delay non-matching to sample ▪ Presented with an object, then a delay, then have to select the object out of the two that is different from the one presented on it’s own – have to remember the previous object and select a new one - Take out medial temporal lobe in a monkey and see what happens in delayed non-matching to sample task o Normal animal – perform at about 90% correct ▪ Doesn’t seem to matter how long delay is • Delay anywhere from 8-10 seconds to 2-10 minutes o Can still make right choice at roughly 85-90% of the time ▪ Can encode memory then retrieve it o Lesioned animal – performs same as normal animal with a short delay ▪ Shows working memory is in tact • Performance declines to essentially just guessing after long delay o Allows researchers to determine where in medial temporal lobe that they should be looking at to see what is involved in laying down new episodic memories ▪ Take out amygdala – no deficit on task – amygdala doesn’t appear to be involved ▪ Hippocampus removed • Small effect • Involved in encoding new explicit memories ▪ Perirhinal cortex removed • See the largest effect on task • Important for taking episodes that happen and applying them later on Memory functions of the hippocampus - Binds sensory info for memory consolidation o Consolidation – enhances encoding ▪ Makes memories stick ▪ Sleep is important for consolidation - - Hippocampus found in most anterior section o On the dorsal surface underneath corpus callosum under the cortex o Shape and size changes as you go anterior to posterior ▪ Moves more ventrally and laterally as you move anterior to posterior - Supports spatial memory of location of objects that are important to us o Episodic memory tied to location - Lesion hippocampus to test function o Radial arm maze ▪ ▪ Each arm on maze is baited with food • In normally behaviour animal – visits all the arms efficiently o Never revisited an arm that they just got food from – remembers an event from the recent past • In hippocampal lesioned rats – don’t get food efficiently – will revisit arms where they already got food o Can’t use spatial location efficiently ▪ Only some arms baited • Both normal and lesioned animals will only go down baited arms o Don’t just use a random search – don’t go none baited arms o Lesioned animals will go down arms that were previously baited where they got food ▪ Forget recent events o Morris water maze ▪ ▪ Hidden platform in the pool – rat swims around and eventually finds the platform • Eventually, rat learns where platform is and quickly goes to platform o Good memory means short escape time – finds the platform quickly ▪ Does task efficiently with in tact hippocampus • Unable to lay down spatial location of hidden platform when the hippocampus is lesioned o Time to find platform doesn’t improve ▪ Glutamate also involved in pr
More Less

Related notes for PSYO 2470

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit