Lecture 8- Memory, Time and Prediction Flashcards
How did H.M. compare to controls in estimating time?
- Experimenter left and task was to reproduce the time interval created by the experiment
- Controls were pretty good, H.M. however (hippocampal damage) line was a lot flatter meaning his estimates were within a lot more narrow of a window. In other words, H.M’s ability to estimate time was impaired.
How were order judgements shown to be impaired in amnesia patients?
- Patients with hippocampal lesions were shown to be impaired in recall events in the order in which they actually happened
- Shown in experiment where had to walk through a shopping center and recall order of what they did later.
- The hippocampus is invovled in the timing + sequencing of events
What is a potential mechanism for the hippocampus involvement in estimating time?
- Time cells similar to place cells.
- Shown when animals were in a wheel. Had be in the wheel for a certain amount of time then got reward. Analyzing neurons showed them firing at different times- some seem to be activated earlier on in the task while others only became activated later (in this how time is indicated to the animal).
What is an alternative hypothesis that could explain the animal’s knowledge of how long they are in the wheel for? What was done to address this issue?
- Distance cells, just responding to how much effort the body has gone through (kinesthetic)
- To address researchers changed the task so that a treadmill was used for running and this had different speeds. If it is distance cells not time cells being used as indicators then we would expect cells in different conditions to peak at different times. But they all peaked at same time. (the varying distance travelled did not matter).
Complete the sentence:
If time perception depends on activity in neural systems then…
perception can be altered by changes in neural system activity
Draw a flow chart showing Gibbon’s Scalar expectancy theory (SET)…
- This a prominent theory of timing
- Answers in one note/ slides
How can internal pacemakers be used to indicate time and how would perception differ between a normal and face speed?
- Cycles of the internal pacemaker correspond to a particular event and this can then help in interpreting the time/ reproducing it (think metronome)
- If an internal pacemaker is fast then more cycles will fit into the same amount of time. Therefore, if we are using pace maker cycles estimates of time will as experienced as longer and reproduction of time will be smaller/ underestimated.
What is the difference between time estimation and time production?
- Time estimation= How many B’s are there? Then – how long did that take?
- Time reproduction= Hold down mouse button for a certain number of seconds (5-30)
What are the effects of THC on time perception?
- Showed that in all doses (low, medium and high) overestimated duration of time compared to placebo
- Then underestimated in time production. Again seen in all doses.
- This is consistent with an increase in clock speed.
Does time seem to slow down during a life threatening situation?
- Theory is that nervous system attempts to spilt the experience into smaller and smaller chunks. i.e. that the pacemaker would speed up.
- Tested with the Suspended Catch Air Device (SCAD) in Texas (the theme park one)
- Participants first estimated time when watching someone else and then by doing it themselves
- The wore wrist watches that showed random flashing digits and had to say if they saw the numbers or not.
- If pace maker has speed up then yes they should be able to see numbers.
- There was a difference in estimation with those that experienced the fall feeling like it was longer than when they just watched (consistent with increase in pacemaker speed)
- The accurate digit identification didn’t really work though both groups performed equally as bad while it was predicted that those in the fall would perform better than those on the ground due to time expansion
What is chrono stasis? Why does it occur?
- The phenomenon that when you look at the clock the hand appears to freeze for a bit when first look at it.
- It occurs due to attempts of the visual system to stabilize what is being seen. During Saccade (when shift eyes/ vision) – visual system suppresses input to prevent blurring. Upon Fixation – nervous system fills in gap retrospectively but for the clock this is taken from the ‘end’ point and means the clock appears to stop.
Can time perception be modulated on a moment by moment basis?
Yes, shown by the blue and red square they are the same size but because nervous system is predicting based on the expansion pattern they appear to be different sizes.
When you recall a memory are you reactivating the network that was
involved in encoding it?
- Data suggests that content-sensitive patterns of neural activity expressed during perceptual experiences are reexpressed when experiences are remembered, a phenomenon termed reactivation.
- I.e. fMRI scans show that individuals reactivate the regions that were invovled in the experience. This is not however, occurring in a one to one correspondence as memory storage involves compression.
Brain activity mapping between encoding and retrieval is not exact
Why might that be?
- Noise in the system or different contexts (things might have happened in between/ not going to have all the same cues)
- Distinct origin of input signals – perceptual vs temporal cortex
- Task demands – memory search
- Shift towards conceptual representations - consolidation
- Reconsolidation of memory (Encode information: stored for brief period in a liable, adjustable form (prone to change))
Simply put what is the interaction that occurs between memories in an active labile state and an inactive fixed state?
- Encoding leads to an active labile (adjustable) state consolidation results in a fixed inactive state of the memory trace
- Reactivation/ retrieval brings the memory back into the active labile state where it can be adjusted by new experiences, memories, information etc. (explains why memory is prone to suggestion). You bring in related information to the trace.
- Reconsolidation gets the trace back to a fixed inactive form
