College aantekeningen Leren en geheugen (5102LEGE9Y) Week 5
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Course
Leren en geheugen (5102LEGE9Y)
Institution
Universiteit Van Amsterdam (UvA)
Book
Principles of Neural Science, Sixth Edition
Een uitgebreide en overzichtelijke samenvatting van de hoorcolleges uit week 5 voor deeltentamen 2 van het vak Leren en Geheugen van de studie Psychobiologie aan de UvA ().
Inhoud
College 11: Visueel sensorisch- en werkgeheugen (29-30/11) .................................................................................. 2
1. Introductie: Geheugen is niet 1 ding ..................................................................................................................... 2
2. Visible persistance.................................................................................................................................................. 4
3. Iconic memory en working memory ...................................................................................................................... 6
4. Het gecombineerde VSTM paradigma .................................................................................................................. 8
5. Multiple levels in VSTM: neural basis .................................................................................................................. 12
6. Samenvatting en conclusie .................................................................................................................................. 16
Vragenuur................................................................................................................................................................... 16
College 12: Episodisch en semantisch geheugen ..................................................................................................... 17
Start ............................................................................................................................................................................ 17
1. Episodisch en Semantisch geheugen ................................................................................................................. 18
2. Ontwikkelen en gebruiken van declaratief geheugen........................................................................................ 22
3. Vergeten ................................................................................................................................................................. 24
4. Declaratief geheugen wordt mogelijk gemaakt door hippocampale en neocorticale netwerken. ............... 24
College 13: Hippocampus functie: van navigatie naar episodisch geheugen ........................................................ 32
Start ............................................................................................................................................................................ 32
1. Navigeren met een allocentrische of een egocentrische representatie van de ruimte. ................................ 32
2. Place cells en de cognitive map theory. ............................................................................................................. 36
3. Twijfel over de cognitive map theory. .................................................................................................................. 43
4. Neurale codering van “tijd” in de hippocampus................................................................................................ 49
5. Grid cellen in de mediale entorhinale cortex ..................................................................................................... 53
,College 11: Visueel sensorisch- en werkgeheugen (29-30/11)
Deze zelfstudiemodule gaat dieper in op de relatie tussen visible persistence, visueel sensorisch geheugen
en werkgeheugen. Het sluit aan bij de colleges van Simon van Gaal over Perceptie en Bewustzijn in de cursus
eerder dit jaar. Hierin werd al gesteld dat er enige tijd zit (maar niet veel!) tussen het ervaren van visuele
informatie en de mogelijkheid om daarover te rapporteren, en dus de betrokkenheid van een bepaalde (zeer)
korte termijn vorm van geheugen. Waar ligt eigenlijk de grens tussen het sensorische geheugen en het
werkgeheugen en/of zit daar nog iets tussenin? Wat is de bottleneck en kunnen we deze met slimme
experimentele paradigma's omzeilen? Wordt het tijd om het bekende modal memory model van Atkinson &
Shiffrin (1968) (zie onderstaande figuur) wat aan te passen?
Stof bij deze zelfstudie module is een apart hoofdstuk van Irwin & Thomas over visual short term memory
Download hoofdstuk van Irwin & Thomas over visual short term memory. Dit hoofdstuk is vooral bedoeld ter
ondersteuning van de college slides. Je hoeft alleen die stukken te kennen die direct betrekking hebben op de
stof uit dit college.
1. Introductie: Geheugen is niet 1 ding
❖ We will focus on: Visual persistance, visual sensory memory & visual working memory
➢ Different stages of memory & processing
➢ Neural basis
❖ There is a hierarchy to this system
➢ visual persistance: retinal level (of the eye)
➢ visual sensory memory: the back of the
brain (occipital cortex, V1, V2, V3, V4 & IT?)
➢ visual working memory: highest level, the
front of the brain (de gebieden die hij
noemt kan ik niet goed verstaan)
Visual sensory memory
❖ Als je een afbeelding ziet, dan maak je meteen een iconische herinnering aan
➢ Reports of ‘seeing’ a scene after is disappeared
▪ This introspective description was suggestive of some kind of “single, visible,
precategorical, high-capacity, quickly-decaying memory that holds incoming visual
stimulation for further processing” (Loftus & Iwrin, 1998)
Memory is not 1 thing
❖ Sensory information coming in -> sensory buffers
(less than a second) -> encoding into shorter term
memory (a few seconds) -> working memory (in the
front of the brain, the basis for most of your actions,
like retrieval -> performance)
Visual sensory memory is not 1 thing either!
, ❖ There has been a lot of discussion about visual sensory memory
❖ We will now look at the idea that visual sensory memory consists of 2 stages:
➢ Iconic memory stage & fragile memory stage
❖ How the brain enables iconic memory is not known yet
❖ We have to distingish between “visible persistence”, “visual analog” and “postcategorical
information”
➢ We can call these concepts retinal afterimages, iconic (low-level icon), and fragile memory
(high-level icon), respectively
➢ You can say that postcategorical information is visual sensory memory but also encompasses
visual working memory?
A big question
❖ Why are we intersted in this?
➢ Consciousness (‘anything that exists from a first-person perspective’) cannot be described as
a singular phenomenon
▪ Instead, consciousness is layerd:
o Perceptual/sensory awareness: seeing, hearing etc.
• our brief, yet highcapacity iconic memory
▪ sensory memory seems to be a reflection of sensory awareness
• e.g. visual experience: you see a lot of objects, you do not need
attention for it, rich picture
o Cognitive/reflective awareness: aka. things we can talk about or think about
• our sustained, but limited-capacity working memory
▪ working memory seems to be a reflection of this
• not parallel but serial, you do need attention for it
▪ We see the same kind of distinction in sensory memory. That is why memory tasks are
a good tool for investigating consciousness.
❖ Cortical blindness:
➢ eyes function completely normally, subcortical areas are not affected
➢ but they have a laesion in the occipital cortex -> although the visual information is still
processed by the eye, even neurally by subcortical areas, it is not processed cortically -> no
visual experience!
▪ from their perspective, they are completely blind
➢ Distinction between processing of information and a person having an experience
❖ The same neural mechanisms that underlie memory seem to also underlie awareness
➢ Sensory memory and sensory awareness: back of the brain
➢ Working memory and cognitive awareness: front of the brain
➢ Consciousness: all over the cortical areas
Quiz: voorkennis neuronale communicatie
❖ Channels, gates, and pumps are different proteins embedded in the cell membrane
➢ True
❖ The term diffusion is used to describe an active transport process that eventually will lead to an equal
distribution of molecules and ions
➢ False: it is a passive process and doesn't cost energy
❖ The resting potential is about -70 mV
➢ True
❖ During rest, K+ is free to enter and leave the cell
➢ True
❖ During the relatively refractory period it is impossible to generate another action potential
➢ False
❖ An action potential is the result of the combined influx of Na+ and K+ ions
, ➢ False
❖ EPSPs and IPSPs are both graded potentials that last a few seconds before they decay
➢ False
❖ Neurotransmitters are always synthesized in the cell body according to instructions in the neuron's
DNA
➢ False, there is also another way - some neurotransmitters are synthesized in the axon terminal
from building blocks derived from food
❖ The ultimate action of the neurotransmitter depends on the type of neurotransmitter and the kind of
receptors on the postsynaptic membrane
➢ True
❖ Autoreceptors are involved in the reuptake of neurotransmitters by the presynaptic neuron
➢ False
2. Visible persistance
Ancient history on visual short-term memory (VSTM)
❖ “Memory is, therefore, neither Perception nor Conception, but a state or affection of
one of thses, conditioned by a lapse of time” Translated from On Memory and
Reminiscence by Aristotle (350 BS)
➢ Beware: visible persistance is at work here!
Visible persistance
❖ Visible persistance does not require an intenste blast of light in order to be generated, it is brief in
duration, and it has the same constrast polarity as the originating stimulus (i.e. it is not a negative
afterimage)
➢ A continuation of what we have seen
Storage model of visible persistence
❖ Hydrodynamic metaphor
➢ Some of the sensory storage (all of what you see is stored in there, in
the retinal level / somewhat behind the retina) gets passed on to the
relevant areas
➢ Not everything that you see goes into sensory memory
➢ Visual persistance is actually just the continuation of all the
information coming in
❖ Electrodynamic metaphor
➢ Close to what is actually happening
➢ Image -> Sensory storage is electrical information for a very short time, a continuation of firing
if your retinal cells.
▪ The retinal cell stay active although the actual image is
not there anymore
▪ The visual persistance is there until the cells no longer fire
How can we measure the duration of visible persistance?
❖ Task: determine the matrix location of missing dot
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