Week 7 - Neural Basis of the self Flashcards
What is the self
In Psychology, common use of the term “Self” in various subject–predicate combinations: Self-knowledge, Self-concept, Self-esteem, Self-awareness, Self- control, Self-perception, Self-reference, etc.
Sense of self
*The self as a “multiplicity of cognitions, each of which may reflect the action of a different neural system” (Skowronski & Sedikides, 2019)
*“The self may best be construed as a set of interrelated, functionally independent systems” (Klein, 2010)
*However, our experience of selfhood is experienced as stable over time/continuous (“Stream of consciousness”, James, 1890)
Sources of Self-Knowledge
- episodic memories of one’s life events
- Semantic summary representations of ones personality
- Semantic knowledge of facts about ones life
- An experience of continuity through time: the ‘i’ experienced now is connected to the ‘‘i’’ experienced at previous points
- A sense of personal agency and ownership: the belief or experience that ‘‘i’’ (agency) am the cause of ‘‘my own’’ (ownership) thoughts and actions
- The ability to self-reflect: forming meta representations where the agent is the self and where the agent makes inferences on the basis of those representations
- The physical self: represent and recognising (e.g., in mirrors, photographs) one’s body
Objective measures of LTM
Objective:
- Laboratory tests: testing memory for a list of words, pictures, faces that participants will have studied.
- Public events tests: testing memory for events in the public domain (e.g., about London Olympics, lockdown, etc.)
- Autobiographical memory tests: testing personal memories that can be checked by a family member; or that would have been encoded in a controlled environment (participants wearing portable camera)
Memory systems
Short term memory (Working memory)
Long term memory:
declarative (explicit):
- Episodic: personal episodes in time and spaces
- Semantic: facts, meanings, concepts, knowledge about the existing worlds
Non declarative (implicit)
- procedural
- priming and perceptual learning
- simple classical conditioning
- non-associative learning
Brain regions involved in memory systems
- Episodic: Hippocampus, medial temporal lobe, neocortex
- Semantic: lateral and anterior teporal cortex, prefrontal cortex
- Procedural: Striatum, cerebellum, motor cortex
- Priming and perceptual learning: neocortex
- Simple classic conditioning: amygdala and cerebellum
- Non-associative learning: reflex pathways
Subjectove measures of LTM
Subjective:
- Autobiographical Memory Tests : asking about Vividness, Sensory details (richness of memories), Confidence, Perspective when re-experiencing (1st person-Actor/3rd person-Observer), Emotion, Remember versus Know judgement
- “Laboratory” Tests: Remember versus Know judgement for each stimulus
Brain regions involved in self-relevance / subjective memory
Medial Prefrontal Cortex
(mPFC)
see a photo of it
- The mPFC is involved in self-referential processing and representation of self-relevant information.
- The link between medial mPFC and self-referential processing was supported by a study that found greater activation in this region when participants recognized photos taken by themselves (self) compared with photos taken by other participants (other
Medial Prefrontal Cortex
(mPFC): Patient Studies
- Damage to the mPFC abolishes the self-reference effect (SRE) → mPFC is necessary for the SRE and important for self- referential processing and the neural representation of the
self - Bilateral damage to mPFC was also associated with impaired personal trait knowledge, but spared other-person trait knowledge (Marquine et al., 2016)
The ventral parietal cortex
look at lecture slides for photo of it
- The ventral parietal cortex and in particular the angular gyrus is: a convergence zone (integrating information from multiple sensory modalities)
- associated with subjective aspects of memory retrieval (1st person perspective, confidence) and
the richness of information recalled
Ventral Parietal Cortex: Patient Studies
- Bilateral damage causes impaired free recall of autobiographical memory – freely recalled Ams
were lacking in detail. The memory deficit disappeared when memory was specifically probed by asking pointed questions (Berryhill et al., 2007). - Ventral parietal lesions affect subjective aspects of recollection to a greater extent than objective performance
Ventral Parietal
Cortex: TMS studies
- Disrupting ventral parietal cortex (the angular
gyrus) function with cTMS reduces free recall performance and 1st person perspective (Bonnici et al., 2018). - Disrupting ventral parietal cortex (the angular gyrus) function with cTMS reduces confidence more than objective performance (accuracy; Yazar et al., 2014
Brain correlates of 1st person perspective during retrieval
- First-person (field or own-eyes) memories tend to be rated higher on subjective vividness,
sensory details, and emotional intensity, as compared to 3rd (observer) person perspective - First person perspective is more commonly experienced when retrieving recent events; and 3rd person perspective when imaging future events (St Jacques, 2019), or remembering more remote events.
Which areas activate regardxing bodily self and viewpoint specific mental imagery?
Bodily self (the ‘‘me’’ that remembers): Somatomotor cortex, insular cortex, temporal parietal junction
Viewpoint specific mental imagery (from where ‘‘i’’ perceive the memory:
Angular gyrus, Precuneus
Personal vs Non memory systems
Semantic:
Personal: Autobiographical content,
Non Personal: shared across individuals / cultures
Episodic:
Personal: Autobiographical content
Non-Personal: Lab stimuli
Episodic memory
PERSONAL (autobiographical content) AND NON PERSONAL (lab stimuli)
Autobiographical:
- Experiencing everyday events
- Test: Being able to remember these events, re-experience them
- Remember context/source: where you where, when it occurred, all details that you can
remember
Lab Material:
- Learning list of items (e.g., words, faces, pictures)
- Test: Being able to remember seeing these items in the
experiment
- Remember context or source: e.g., side of screen the item was presented, or in which list a word was presented
Episodic memory: Advantages of Lab vs Autobiographical material
Using lab items:
- Allow to measure accuracy (objective memory performance)
- Participants have a very similar experience
Using «_space;real life»_space; autobiographical material:
- more ecological
- Allows studying phenomenlogical properties of episodic memories such as:
Perspective when re-experiencing (1st person-Actor/3rd person-Observer)
Sensory details
Vividness
Emotional Valence
Semantic Memory
- General world knowledge (such as knowledge of facts, events, concepts, objects, and people), retrieved independently from its original spatial or temporal context.
- Semantic processing refers to processing the meaning of stimuli
Examples:
- 1984 is a book that was written by George Orwell
- The definition of a birthday party; knowledge of events that typically happen at birthday parties.
Tasks used to study semantic memory:
- Sentence verification (A duck is a bird; A horse is a bird)
- Naming of category instances
- Production of semantic associates or opposites
- Feature-dimension decision (such as judgements on real world size or indoors/outdoors classification)
- Feature/Attributes listing (e.g., is an animal, has 4 legs, fur, makes “woof” sound)
Semantic memory is impaired in Semantic Dementia, a progressive neurodegenerative disorder characterized by a selective loss of semantic memory (Lambon Ralph et al., 2016)
Semantics?
We use conceptual knowledge with so much ease that we tend to take it for granted (the world is full of meaning for us!)
- Inherent part of on-line cognition
Includes:
- Names and physical attributes of all objects,
- The names and attributes of actions
- Abstract concepts and their names
- Knowledge of how people behave and why
- Opinions and beliefs
- Knowledge of historical events
- Knowledge of causes and effects, associations between concepts
- and so on… (Binder & Desai, 2011)
Personal Semantics
- Early case studies: PS was described in patients who could retrieve few or no episodic memories yet showed knowledge of events from their personal past (Cermak & O’Connor, 1983), resembling a “skeleton autobiography” (Warrington & McCarthy, 1988) that seemed “to be drawn entirely from a personal pool of generalized knowledge” (Cermak & O’Connor, 1983; see also Tulving, 1988).
- In these original studies and typically thereafter, PS was considered as a form of (general) semantic memory
- Very few studies have compared personal semantics to both general semantics and episodic memory, and PS is currently not integrated in models of declarative memory and knowledge
- The majority of autobiographical memory studies have investigated specific autobiographical events / episodic memory
Personal Semantics: more common than episodic memories?
- Barsalou (1988) and Conway (1987) were perhaps the first to report that a large proportion of the content of autobiographical memories concerns knowledge of repeated personal events / personal knowledge
- Suggest that personal semantics may play an important role in autobiographical memory retrieval, particularly to access unique episodes (Conway & Pleydell-Pearce, 2000)
New versions of autobiographical interview
- New version of the Autobiographical Interview (AI) that allows to separate episodic , general semantics, and different types of personal semantics details, as well as other types of details from interview transcripts
What happens when we externalise the
autobiographical self online?
- On one hand, many of our life details may no longer need to be internally stored and retrieved if we know that we can later refer to our online journals to locate the information. As a result, personal events that are posted online may become less likely to be remembered than those that are not posted.
- On the other, posting personal events online affords opportunities for rehearsal and meaning- making (Wang, 2013a). Events are likely to become well integrated into the autobiographical knowledge base and effectively stored for long-term retention. This is in line with the
autobiographical memory literature that highlights the contribution of rehearsal and social sharing to remembering personal experiences
