Summary of Human Affective and Social Neuroscience
Human Affective and Social Neuroscience: Student Guide
Introduction
Memory and neural plasticity are tightly linked: the brain's ability to change its connections underlies how we learn, store, and lose information. This material explains the cellular mechanisms of plasticity, how emotion affects consolidation and reconsolidation, and practical implications for forgetting and therapy.
Key concepts at a glance
- Neural plasticity: the ability of neural circuits to change structurally and functionally in response to experience.
- Synapse: the contact site where one neuron communicates with another; can be electrical or chemical.
- Consolidation: stabilization of a memory trace after initial acquisition.
- Reconsolidation: process by which a retrieved memory becomes labile and is consolidated again.
Definition: Neural plasticity is the set of changes in neuronal structure and function that occur in response to experience or injury.
1. Synapses and structural plasticity
Types of synapses
| Feature | Electrical synapse | Chemical synapse |
|---|---|---|
| Speed | rapid | slower |
| Synchrony | yes | can be asynchronous |
| Plasticity | low | high |
| Signal modulation | limited | amplifies or reduces signal |
Chemical synapse structure
- Presynaptic terminal with vesicles containing neurotransmitter
- Synaptic cleft
- Postsynaptic membrane with receptor proteins (e.g., AMPA, NMDA)
Definition: Long-term potentiation (LTP) is a long-lasting increase in synaptic strength following high-frequency stimulation of a synapse.
Dendrites and spines
- More dendritic branches = more possible routes for information flow.
- More dendritic spines = potential for stronger or additional synaptic contacts.
- Structural changes after LTP often include formation of multiple new spines.
2. Mechanisms of synaptic strengthening and weakening
LTP (how memories form)
- Triggered by coordinated pre- and postsynaptic activity.
- Involves insertion/upregulation of AMPA receptors and activation of NMDA receptors to allow calcium influx.
- Structural effects: spine enlargement and formation of new synapses.
Forgetting (pruning)
- Synaptic loss or pruning can reduce stored information.
- Microglia participate in elimination of old or weak synapses.
Definition: Synaptic pruning is the process by which weaker synaptic contacts are eliminated, refining neural circuits.
3. Emotional modulation of memory (consolidation)
Consolidation basics
- Consolidation stabilizes a newly acquired memory trace across time.
- Emotional arousal often enhances consolidation.
Neurochemical cascade during emotional arousal
- Emotional events increase peripheral epinephrine and cortisol.
- Brain norepinephrine rises via activation of the locus coeruleus.
- Norepinephrine acts on beta-adrenergic receptors in the amygdala, which then modulates consolidation in other brain areas.
- Cortisol acts on glucocorticoid receptors to further influence consolidation.
Definition: The locus coeruleus is a brainstem nucleus that releases norepinephrine widely, modulating arousal and memory consolidation.
Practical example: A sudden emotionally charged event (e.g., narrowly avoiding an accident) triggers norepinephrine release, making details of that event more strongly consolidated and easier to recall later.
4. Reconsolidation and therapeutic implications
Reconsolidation process
- When a memory is retrieved it becomes labile and must be reconsolidated to persist.
- During this labile window, memories can be modified, weakened, or strengthened.
Applications
- Targeting reconsolidation offers a route to modify maladaptive memories (for instanc
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Memory and Plasticity
Klíčová slova: Affective neuroscience: social & clinical, Neuroanatomy, Clinical pharmacology, Administration, Memory and plasticity, Neuroimaging methods, Affective neuroscience: emotion circuits, Microbiota and behavior, Motivation and reward
Klíčové pojmy: Neural plasticity is change in neural structure/function due to experience, LTP increases synaptic strength via NMDA activation and AMPA insertion, Structural LTP effects include spine enlargement and new spine formation, Microglia contribute to synaptic pruning and forgetting, Emotional arousal raises norepinephrine via locus coeruleus enhancing consolidation, Amygdala modulates consolidation through beta-adrenergic receptors, Reconsolidation makes retrieved memories labile and open to modification, Beta-adrenergic antagonists can reduce emotional intensity of some memories, Emotional interventions often reduce affective salience but not factual content, Biogenic amines and amino acids are synthesized in presynaptic terminals, Neuropeptides are synthesized in cell bodies and transported, Electrical synapses are fast and synchronous; chemical synapses are plastic