4. Learning, Memory, and Emotions

Question 1

H.M.

Answer 1

Led to understanding that learning and memory are tied to biological processes. Following childhood blow to the head, developed seizures and underwent an experimental procedure that removed sections of his medial temporal lobes, including most of his hippocampi. Seizures abated, but was left with permanent amnesia. Could remember events before surgery, but was unable to form new memories
Now know that medial temporal lobe, which includes hippocampus and parahippocampal regions, works with other regions of cerebral cortex regarding memories

Question 2

Declarative memory

Answer 2

Facts, data, events. Explicit because you consciously recall and describe the information. Semantic or episodic

Question 3

Semantic memory

Answer 3

Cultural knowledge, ideas, and concepts accumulated about the world. E.g., names of capitals, vocabulary, how to add, dates of historical events. Involves cortical regions beyond hippocampus

Question 4

Episodic memory

Answer 4

Personal experiences

Question 5

What brain region mediates emotional significance attached to memories of events?

Answer 5

Amygdala

Question 6

How is the “what” of episodic memories encoded?

Answer 6

Parahippocampal region aids hippocampus

Question 7

Semantic and episodic memory are examples of what form of declarative memory?

Answer 7

Long-term

Question 8

Did H.M. struggle with long-term declarative memory, and why or why not?

Answer 8

He did not, because it is stored throughout a large network of cortical areas

Question 9

Working memory

Answer 9

Short-term declarative memory

Question 10

Brain’s capacity for long-term vs short-term memories

Answer 10

Brain seems to possess unlimited capacity for long-term memory, but short-term memories are limited to small amounts of information for small periods of time. Accessible while being processed and manipulated, but unless transferred to long-term memory, will decay after a few seconds

Question 11

Did H.M. struggle with working memory, and why or why not?

Answer 11

He did not, because it is coordinated by the PFC

Question 12

Spatial memory - neural basis

Answer 12

Navigational memories involved in creating mental maps are tied to place cells in the hippocampus. Grid cells, located in entorhinal cortex (area near hippocampus), represent coordinates that allow the brain to track your position in space

Question 13

Nondeclarative memory

Answer 13

Implicit/procedural memory. Stored and retrieved without conscious effort. Used when performing learned motor skills.

Question 14

Did H.M. struggle with nondeclarative memory, and why or why not?

Answer 14

Did not lose this type of memory, still able to acquire new motor skills despite not being able to remember doing them before

Question 15

3 important brain areas to nondeclarative memory

Answer 15

Basal ganglia (“habit centre”), PFC, and cerebellum (involved in motor control and coordination)

Question 16

Why can the brain form memories and rewire itself in response to experience?

Answer 16

Because neural circuits change at synapses

Question 17

Synaptic plasticity

Answer 17

Ability of synapses to remodel themselves

Question 18

Encoding a long-term memory involves…

Answer 18

Persistent changes in the number and shape of synapses, the amount of neurotransmitter released, and the number of receptors

Question 19

What animal was used to study synaptic plasticity, and why?

Answer 19

Sea slug, Aplysia californica, because its nerve cells are relatively few and easy to observe

Question 20

Two molecular components critical to the formation of long-term memories

Answer 20

Genes governing NMDA receptors (type of glutamate receptor) and cAMP-response element binding protein (CREB)

Question 21

Two processes key for synaptic plasticity

Answer 21

Long-term potentiation and long-term depression

Question 22

Long-term potentiation

Answer 22

Long-lasting increase in synaptic strength. Occurs in many areas but especially in hippocampus. Involves increase in glutamate receptors. Once glutamate is bound, calcium and sodium ions flow into cell. Increasing receptors strengthens a synapse by allowing the entry of more ions

Question 23

Long-term depression

Answer 23

Decreases a synapse’s effectiveness

Question 24

Effects of LTP and LTD on calcium ion concentration inside post-synaptic cell

Answer 24

LTP boosts concentration of calcium ions inside a postsynaptic cell, LTD increases it to a lesser degree.

Question 25

Enzymes activated by differences in calcium ion concentration in LTP and LTD

Answer 25

Kinase proteins in LTP, phosphatases for LTD. These enzymes modify synapses, making them more or less efficient

Question 26

Series of events in LTP that stabilizes synaptic changes

Answer 26

Increase in calcium ions activates cAMP molecules, which activates different enzymes, some of which increase the number of receptors, making the synapse more sensitive. Continued stimulation through repetitive experience activates CREB, which acts in the nucleus of the neuron to switch on genes that direct protein synthesis. Among proteins produced are neurotrophins, which stimulate growth of synapse and structural elements, stabilizing increased sensitivity of synapses

Question 27

Stabilizing of synaptic changes in LTP is critical for…

Answer 27

Memories becoming long-term

Question 28

Where are declarative memories encoded?

Answer 28

Hippocampus

Question 29

Where are declarative memories transferred for long-term storage and consolidation?

Answer 29

Frontal lobes. Over time, hippocampus becomes less important for retrieving older memories as frontal cortex assumes that task

Question 30

Emotional memory

Answer 30

Nondeclarative memory. Learned emotional responses become attached to stimuli over time

Question 31

Who identified 6 basic emotions, and what are they?

Answer 31

Paul Ekman; anger, fear, surprise, disgust, joy, and sadness

Question 32

Structures most closely linked to emotions

Answer 32

Amygdala, insular cortex, periaqueductal grey. Neurons from PFC, amygdala, and insular cortex project to periaqueductal gray, which has connections with amygdala, thalamus, hypothalamus, brainstem, and spinal cord

Question 33

Role of amygdala in emotion

Answer 33

Integrates emotions and motivation. Interprets fear. Identifies social rewards and how to attain them. Classical conditioning (association of stimulus with reward or punishment) is dependent on amygdala

Question 34

Role of insula in emotion

Answer 34

Responsible for disgust. Implicated in feeling and anticipating pain. Takes in system-wide inputs and generates subjective feelings about them.

Question 35

Role of periaqueductal grey in emotion

Answer 35

Tied to pain perception and stress responses. Located where incoming sensory information is acted on by higher brain centres. Receptors for pain-reducing compounds like opioids are clustered in periaqueductal gray

Question 36

Affective decision making

Answer 36

Making choices under risky conditions. Teens make more risky decisions because PFC isn’t fully developed yet. Older adults also make more risky decisions because PFC function diminishes with age

Question 37

Why do we remember rewarding things?

Answer 37

Dopamine influences synapses in reward pathway (hippocampus, amygdala, PFC) to create emotional associations with rewards

Question 38

Reward pathway

Answer 38

Mesolimbic pathway. Connects ventral tegmental area (VTA) to nucleus accumbens.

Question 39

Is it the reward or the expectation of a reward that most powerfully influences emotional reaction?

Answer 39

Expectation. Reward learning occurs in response to an unexpected reward. If a reward is greater than anticipated, dopamine signalling increases. If less, it decreases. Correctly predicted reward doesn’t change anything.

Question 40

Go-getters have…

Answer 40

Greater dopamine signalling in striatum and PFC

Question 41

2 examples of abnormal circuitry in reward system leading to inappropriate aggression

Answer 41

Lateral habenula, major node in reward circuitry, encodes punishment by inhibiting dopamine release. Dysfunction linked to inappropriate aggression.

Stimulating amygdala triggers rage and aggression. Removing parts of it makes animals more docile.