Task 4: Sleep and memory
What are the processes behind memory and which of these are affected by sleep?
A. Nondeclarative/implicit memory = unconscious memories that operate automatically. They do
not seem to require memorization or include facts or experiences; instead, they control
behaviors -> does not need medial temporal lobe
The key form is the acquisition of specific motoric behaviors and skills (driving a car, etc.) ->
these activities can be performed without being able to describe them or being aware of all
the movements involved.
B. Declarative memory/explicit memory = memory of events and facts that we can think and talk
about. Includes episodic and semantic memories -> relies on medial temporal lobes and
connected brain areas (includes hippocampus)
i. Episodic memories: involve
remembering events and their context
(what, when, where and in what order).
Are specific to time and place.
ii. Semantic memories: involve facts
without contextual information and are
less specific than episodic memories.
They can be learned gradually, unlike
episodic memories which must be
learned all at once.
The conception of a memory begins with the process of encoding, resulting in a stored representation
of an experience within the brain. For memories to persist over the longer time course (minutes-years),
consolidation appears to be necessary, affording memories greater resistance to decay (a process of
stabilization) or even improved recollection (a process of enhancement).
Consolidation = a process that transforms new and initially labile memories encoded in the
awake state into the network of pre-existing long-term memories -> involves active re-
processing of fresh memories within the neuronal networks that were used for encoding them.
Sleep particularly promotes the consolidation of memory (memory encoding and retrieval take
place most effectively during waking).
o Declarative is enhanced by SWS
o Non-declarative enhanced by N2 and REM
How does sleep affect emotional regulation?
Affective reactivity
Sleep loss amplifies negative emotional consequences of
disruptive daytime events while blunting the positive benefit
associated with rewarding or goal-enhancing activities.
One study: sleep deprivation of 36h -> affective stimulus
viewing task from emotionally neutral to aversive and
negative -> 60% greater magnitude of amygdala reactivity
(fMRI) -> three-fold increase in the extent of amygdala
volume in response to the aversive stimuli -> significant
loss of functional connectivity identified between the
amygdala and the mPFC (mPFC = region known to have
strong inhibitory projections and hence modulatory impact
on the amygdala) > greater connectivity observed
between the amygdala and the autonomic-activating
centers of the LC.
o Without sleep, amplified hyperlimbic reaction by the amygdala was observed in response
to negative emotional stimuli.
o Night of sleep may “reset” the correct affective brain reactivity to next-day emotional
challenges by maintaining functional integrity of mPFC-amygdala circuit -> govern
appropriate behavioural repertoires (e.g. optimal social judgements and rational
decisions).
Emotional information processing
What are the processes behind memory and which of these are affected by sleep?
A. Nondeclarative/implicit memory = unconscious memories that operate automatically. They do
not seem to require memorization or include facts or experiences; instead, they control
behaviors -> does not need medial temporal lobe
The key form is the acquisition of specific motoric behaviors and skills (driving a car, etc.) ->
these activities can be performed without being able to describe them or being aware of all
the movements involved.
B. Declarative memory/explicit memory = memory of events and facts that we can think and talk
about. Includes episodic and semantic memories -> relies on medial temporal lobes and
connected brain areas (includes hippocampus)
i. Episodic memories: involve
remembering events and their context
(what, when, where and in what order).
Are specific to time and place.
ii. Semantic memories: involve facts
without contextual information and are
less specific than episodic memories.
They can be learned gradually, unlike
episodic memories which must be
learned all at once.
The conception of a memory begins with the process of encoding, resulting in a stored representation
of an experience within the brain. For memories to persist over the longer time course (minutes-years),
consolidation appears to be necessary, affording memories greater resistance to decay (a process of
stabilization) or even improved recollection (a process of enhancement).
Consolidation = a process that transforms new and initially labile memories encoded in the
awake state into the network of pre-existing long-term memories -> involves active re-
processing of fresh memories within the neuronal networks that were used for encoding them.
Sleep particularly promotes the consolidation of memory (memory encoding and retrieval take
place most effectively during waking).
o Declarative is enhanced by SWS
o Non-declarative enhanced by N2 and REM
How does sleep affect emotional regulation?
Affective reactivity
Sleep loss amplifies negative emotional consequences of
disruptive daytime events while blunting the positive benefit
associated with rewarding or goal-enhancing activities.
One study: sleep deprivation of 36h -> affective stimulus
viewing task from emotionally neutral to aversive and
negative -> 60% greater magnitude of amygdala reactivity
(fMRI) -> three-fold increase in the extent of amygdala
volume in response to the aversive stimuli -> significant
loss of functional connectivity identified between the
amygdala and the mPFC (mPFC = region known to have
strong inhibitory projections and hence modulatory impact
on the amygdala) > greater connectivity observed
between the amygdala and the autonomic-activating
centers of the LC.
o Without sleep, amplified hyperlimbic reaction by the amygdala was observed in response
to negative emotional stimuli.
o Night of sleep may “reset” the correct affective brain reactivity to next-day emotional
challenges by maintaining functional integrity of mPFC-amygdala circuit -> govern
appropriate behavioural repertoires (e.g. optimal social judgements and rational
decisions).
Emotional information processing
