what did Mueller & Pulzecker 1900 do
types of memory consolidation
2. System-level (whole brain)
what did Mueller & Pilzecker conclude
what did Wixted say about the shape of forgetting
what did Ebbinghaus (1885) argue
• Ebbinghaus (1885): the forgetting function is such that we forget less and less as time goes by.
what did Jost 1897 argue
• Jost (1897): If two memories have equal strength but different ages, the older trace will decay at a slower rate.
continuous reduction in the forgetting rate is a sign of…
continuous reduction in the forgetting rate is a sign of consolidation
what is cellular consolidation
what is Long-term potentiation (Bliss & Lømo, 1973)
• Long-lasting enhancement of synaptic efficacy induced by a tetanus (short burst of high-frequency stimulation) to the presynaptic neuron.
what amnesia did HM hae
anterograde amnesia and temporally graded retrograde amnesia
what is anterograde amnesia
anterograde amnesia: inability to form new declarative memories (the ‘what’)
what is temporally graded retrograde amnesia
temporally graded retrograde amnesia: impairment of memories formed prior to surgery, stronger for young than old memories (Scoville & Milner, 1957) (Ribot’s law, 1881).
what is systems consolidation
• Declarative memories becoming independent from the hippocampus and more dependent on the neocortex is referred as ‘systems consolidation’.
what did Bayley et al 2006 find
Bayley et al. (2006; Manns et al. 2003): 6 amnesic patients with damage limited to the hippocampal region.
Asked Ps about news (1951-2005). Performance with controls and patients is shown right. Old memories are preserved in patients because they have had time to be cloned and presented elsewhere in the brain. The new events has worse performance in patients. However, for most memories, they are the same level as controls.
what did Smith adn Squire 2009 do
160 questions on news events over 30 years
There is a stronger hippocamus activation for newer memories. Older memories show activation in the neo-cortex
what did takashima do
Takashima et al had paired learning protocol. You have to associate a given face with a given orientation of an arrow (shown in B). this is training phase. The test phase is the following day. They need to identify the correct orientation of the face. They got a set of faces leanrt on day one and another group learnt just before the test on day two. The list learnt on day 1 is old. The list learnt before the test is new. They have manipulated age of the memories. Over the course of 24 hours, the memories engage with the hippocampus less but the neo-cortex more.
What is the significance of shift from the hippocampus (in the medial-temporal lobe) to the neocortex?
what are complementary learning systems (Marr 1971, McClelland et al, 1995)
a) A fast learning system that holds information only temporarily (medial temporal lobe, i.e., the hippocampus)
b) A slow learning system that serves as long-term store (i.e., the neocortex)
As both systems (fast and slow) are used to encode new learning, this reactivation/redistribution has to occur ……………
As both systems are used to encode new learning, this reactivation/redistribution has to occur offline, for instance during sleep.
types of declarative memory
episodic and semantic
types of non-declarative memory
procederal skill, conditioning, non-associative, priming
what did Jenkins & Dallenbach 1924 do
Two subjects learn lists of 10 nonsense syllables until mastered
Re-tested in free recall after a varyign time interval (1,2,4 and 8hrs) filled with sleep or wake
what did Jenkins & Dallenbach 1924 find
sleep protects against forgetting
however, absence of interference is not the whole story
time of training has an influence
need less exposure in the evening than the morning for complete mastery