Articles about affective neuroscience, emotion and memory + presentations 9 and 10

Dalgleish, T., Dunn, B. D., & Mobbs, D. (2009). Affective Neuroscience: Past, Present, and Future.. Emotion Review, 1(4), 355– 368. + LaBar, K. S., & Cabeza, R. (2006). Cognitive Neuroscience of Emotional Memory. Nature Reviews Neuroscience, 7(1), 54–64.

ARTICLE: “Affective Neuroscience: Past, Present, and Future”

Until further notice, the flashcards will be based on this article

• Dalgleish, T., Dunn, B. D., & Mobbs, D. (2009). Affective Neuroscience: Past, Present, and Future.. Emotion Review, 1(4), 355– 368.

Give a historical overview of the pioneering work in affective neuroscience of James and Lange

Pioneering work!

The James-Lange Theory

• Emotions are:

  • The experience (/interpretation) of bodily changes that occur in response to emotive cues in the world

  • So, different bodily changes code different emotions

• Remain remarkably influential on contemporary thinking

  • Because of he emphasis it places on the embodiment of emotions, which today sits well with frameworks of embodied cognition

Give a historical overview of the pioneering work in affective neuroscience of Cannon and Bard

Early functional neuroanatomical models!

Critique of James-Lange - Cannon suggest:

• (1) Autonomic activity cannot differentiate different emotional states

  • Findings today:

    • This suggestion has partly been debunked: it seems they can to a certain degree

• (2) Emotional behavior in animals is not impaired when surgically separating the viscera from the brain

  • (viscera - part of limbic system - regulating the bodys automatic functions, linking physiological reactions to feelings and instincts (AI answer))

  • Findings today:

    • Partial disconnection of the brain from the body can actually sometimes reduce emotional intensity

    • Since it is not possible to totally isolate the brain from all aspects of bodily feedback - so (supporting James-Lange) emotional experience may be driven by remaining feedback in separation designs

• (3) Bodily reactions are typically too slow to generate emotions

• (4) Artificial hormonal activation of bodily activity is insufficient to generate emotion

  • Findings today:

    • Some artificial manipulations of organ activity

      can induce emotions - e.g. inducing panic attacks

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The Cannon-Bard Theory

• Cannon developed the first neuroanatomical theory of emotion, later elaborated by Bard

• Suggests:

  • Thalamus and hypothalamus are critically involved in the emotion response to stimuli

    • Evidence supporting hypothalamus’ role: important part of reward network (and therefore motivation)

    • These emotion responses are inhibited (i.e. controlled) by evolutionarily more recent neocortical regions - i.e. thalamic regions

      • Evidence supporting this:

        • Removal of the cortex in cats - freeing the thalamic circuitry from top-down control - allows uncontrolled emotion displays (e.g. anger attacks)

          
          

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Schacter-Singer

• The model accepted today - a hybrid position between James-Lange and Cannon-Bard

• The model suggests:

  • The body contributes to a crude (i.e. rough) sense of emotional intensity

  • The crude sense is then cognitively appraised - leading to more nuanced emotional experience

• Evidence for the model:

  • Studies showing that similar patterns of bodily arousal could be experienced as different emotions - e.g. anger or happiness - depending on the social and cognitive context

Give a historical overview of the pioneering work in affective neuroscience of Hess

Hypothalamic stimulation studies

• Cannon-Bard theory was influenced by Walter Hess’ studies on hypothalamus

  • Hess implanted electrodes into the hypothalamic region of cats

    • Electrical stimulation of one part of the hypothalamus led to an “affective defence reaction” - associated with increased heart rate, alertness, and a propensity to attack

  • Indications of Hess’ findings:

    • Stimulation of certain brain regions can induce animals to act in different ways/recognizable emotional responses - e.g. angry, fearful, curious, lethargic

Give a historical overview of the pioneering work in affective neuroscience of Papez

Development of increasingly sophisticated neuroanatomical frameworks

The Papez Circuit

• An anatomically broader - compared with Cannon-Bard - scheme for the central neural circuitry of emotion

• Suggesting:

  • Sensory input into the thalamus diverge into an upstream “thought” and a downstream “feeling” pathway

    • Thought stream —> link the thalamus to the sensory cortices

      • Especially to the cingulate region

      • Stream continues: —> cingulum pathway —> hippocampus —> fornix —> mammillary bodies of hypothalamus —> mammillothalamic tract —> back again to anterior thalamus

      • Here sensations are turned into perceptions, thoughts, and memories

    • Feeling stream —> transmitted from the thalamus directly to the mammillary bodies

      • Generating emotions - with downward projections to the bodily systems - and then upwards to the cingulate cortex via he anterior thalamus

  • Emotional feelings are:

    • A function of cingulate activity generated through either of the two streams

  • Echoing Cannon-Bard:

    • Top-down cortical regulation of emotional responses is permitted by downward projections from the cingulate to the the hypothalamus

• Today’s views on The Papez Circuit

  • Many of the pathways he proposed exist! - but less evidence that all regions specified are central to emotion

Give a historical overview of the pioneering work in affective neuroscience of MacLean

Development of increasingly sophisticated neuroanatomical frameworks

MacLean’s Limbic System

• A more broadly supported anatomical model of the brain regions involved in emotion and the dominant conceptualization of the “emotional brain” today

  • Built on:

    • Papez’s and Cannon-Bard

    • Studies on monkeys by Kluver an Bucy - “Kluver-Bucy syndrome“

      • Suggesting: key role for temporal lobe structures in normal emotional behavior

        • Later work showed that damage to the

          amygdala accounts for important aspects of the emotional changes

• The brain as a triune architecture with three interacting systems

  • (1) evolutionary ancient reptilian brain

    • Brain areas:

      • Striatal complex + basal ganglia

    • Seat of primitive emotions - e.g. aggression + fear

  • (2) “old” mammalian brain (aka the “visceral brain” / the limbic system)

    • Brain areas:

      • Hypothalamus, thalamus, hippocampus and cingulate cortex, amygdala, prefrontal cortex + other

    • Augments (förstärkar) primitive reptilian emotional responses - e.g. aggression

    • Elaborates social emotions

  • (3) “new” mammalian brain

    • Brain areas:

      • Neocortex

    • The interface of emotion with cognition

      • The seat of top-down control over emotional responses originating within other systems

• Emotion experiences are generated from:

  • Integration - in system (2) (specifically the hippocampus) - of sensations from the world with information from the body

    • Messages about bodily changes - caused by external events - return to the brain and are integrated with ongoing perceptions of the world

Describe Zajonc-Ledoux theory of emotion

• Compare the Z-L theory to the Schacter-Singer theory

Core of the Z-L theory:

• Emotional responsen can occur automatically and instantly at the same time

  • Instantly: without conscious cognitive interpretation or thinking first

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The “low” road / direct pathway

• Route:

  • Senses —> Thalamus —> Amygdala

    • Any sudden, alarming sensory input can trigger the instant survival loop - since the thalamus acts as the main relay station for all senses (except for smell)

• Speed:

  • Extremely fast - “quick and dirty“

• Function:

  • Triggers immediate survival responses for simple emotions

    • (e.g., fear of a snake).

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The “high” road / indirect pathway

• Route:

  • Senses —> Thalamus —> Sensory Cortex —> Amygdala

• Speed:

• Function:

Describe the current state of research on the amygdalas contribution to emotion

Amygdala

• Position in brain:

  • Medial temporal lobe

  • Rests on the anterior tip of hippocampus

• Central research findings

  • Kluver-Bucy syndrome

    • Many of the tendencies in the syndrome can be sufficiently induced by bilateral lesions of the amygdala + disrupting the social behavior of monkeys

• Fear and emotional learning

  • Critical for fear conditioning and for linking stimuli with emotionally significant outcomes

    • 
      

      

    • E.g S.M.

      • In contrast: damage to hippocampus, with intact amygdala, can be fear conditioned with no explicit memory of the conditioning procedure

  • E.g. Amygdala-damage and recognition of fear in facial expressions

    • 
      

      

• Emotional expression and social signals of emotion

  • Amygdala damage can impair the recognition and expression of fear, particularly in response to fearful facial expressions.

    • E.g. S.M.

  • fMRI when presented with fearful faces or fear communicated in other ways (e.g. vocally or bodily movements) show selective brain activation in the amygdala

    • Even when not aware that the fearful face was presented or when presented to blindsight patients

    • Can be modulated by top-down control on attention

• Emotional memory

  • Amygdala activity can enhance the encoding and consolidation of emotionally significant memories

    • Amygdala damage:

      • Does not show usual enhanced memory for emotional aspects of stories

• Take-home message

  • The amygdala is not simply a “fear centre”!

    • It helps detect and evaluate the emotional significance of stimuli + coordinate appropriate learning and responses

Describe the current state of research on the PFC’s contribution to emotion

Phineas Gage

• PFC lesion —> radical changes in personality and emotional behavior

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Guiding behavior

• Integrates emotional information with cognitive processes to guide behavior

  • Involved in learning the emotional and motivational value of stimuli

    • PFC regions work together with the amygdala to learn and represent relationships between new stimuli and primary reinforcer (e.g. food, drink, sex)

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Decision-making:

• The vmPFC uses emotion-related signals from past experience (“somatic markers”) to anticipate the likely consequences of different choices

  • Somatic marker hypothesis (SMH)

    • Somatic marker:

      • Physiological reactions which tag previous emotionally significant events

      • Can be reactivated by cues, providing a signal delineating which current events have had emotion-related consequences in the past

      • Allow decisions to be made in situations where a logical analysis of the available choices proves insufficient

        • Helps anticipate outcomes and guide decisions

  • Patient EVR - lesion in vmPFC

    • Unable to utilize somatic markers

      • Tries and fails to deal with complex situations of uncertainty using logical reasoning alone

    • Iowa Gambling Task

      • Lesion - did not get “hunches” about which cards to choose

      • Non-lesion - unknowingly became sensitive to the delayed rewards and could process their somatic markers that had developed early in the game

  • S.M. patient and amygdala

    • The amygdala seems necessary for initially seating up the emotional response that the vmPFC can regenerate, but it doesn’t seem necessary once the somatic markers have been established.

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Emotion regulation:

• PFC regions contribute to evaluating, and regulating emotional responses

• Emotion regulation = Processes that influence:

  • (1) which emotion one has

    (2) when one has them

    (3) how one experiences and expresses these

    emotion

• Multiple points in emotion generative process can be regulated, affecting the emotion

• Reappraising how we think about or evaluate a situation

  • One of most effective means of regulating our emotions

    • Less useful when emotions are very intense (more useful to redeploy our attention)

    • Less useful when the situation can be modified

  • Associated with activation in PFC

• Increased PFC activity when participants regulated negative emotions - both up- and –down - compared with when just told to look at images

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Take-home message:

• The PFC allows emotional information to be used flexibly:

  • emotions can guide decisions, while cognitive processes can also regulate emotional responses

Describe the current state of research on the anterior cingulate cortex’s (ACC) contribution to emotion

ACC sits at an important interface between cognition and emotional control - contributing to:

• Monitoring emotionally significant information

  • Activates to more subjective elements of pain including empathy for pain and social ostracism

• Conflict and error monitoring

  • ACC is involved in the monitoring of conflict between the current functional state of the organism and any new information that has potential affective or motivational consequences

    • When such conflicts are detected, the ACC projects information about the conflict to areas of PFC where adjudications among response options can occur

• Selecting and adjusting behavior

• Regulating emotional responses

• Integrating emotion, motivation and cognitive control

Describe the current state of research on the insula’s contribution to emotion

Strongly involved in interoception

• Interoception = perception and representation of signals from inside the body

  • E.g. if asked to judge whether ones own heartbeat is simultaneous to a tone

• Helps integrate bodily signals with information form external world

• Provides a link between physiological changes in the body and our subjective emotional experience

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Insula is involved in:

• Awareness of bodily states

  • E.g. heartbeat, breathing and visceral sensations

• Emotional experience

  • By integrating bodily signals with other information

  • Involved in the generation of a risk prediction error - guiding decision-making in risky situations and facilitating learning about uncertain rewards

    • Bodily feedback in decision-making proposed by the somatic marker hypothesis

• Disgust

  • One of the emotions consistently associated with the insula

• Empathy and pain

  • Including responses to our own and others’ bodily/emotional states

ARTICLE: “Cognitive neuroscience of emotional memory”

Until further notice, the flashcards will be based on this article:

• LaBar, K. S., & Cabeza, R. (2006). Cognitive Neuroscience of Emotional Memory. Nature Reviews Neuroscience, 7(1), 54–64.

Flashbulb memories

Definition of flashbulb memory

• A highly vivid memory for how one learned about an emotionally engaging and surprising event

  • Involving memory for the source of the event information - as opposed for the event itself

  • E.g. memory for:

    • Where you were

    • What you were doing

    • Who told you something

    • How it affected you

    • What the aftermath was

Emotion-induced memory enhancement - and the role of amygdala

Consequences of amygdala damage on emotional episodic memory?

• Unilateral damage to amygdala:

  • Does not show enhanced arousal-mediated memory consolidation for emotionally arousing words

    • But instead show parallel forgetting rates for arousing and neutral words from immediate to 1-h retention intervals

• Bilateral damage to amygdala:

  • Show impairments in long-term (1 h to 1 month) recall or recognition of emotional words, pictures and stories1

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Weapon focus / gist memory effect

• When emotionally aroused:

  • Focusing of attention on central gist information at the expense of peripheral details for complex events

    • e.g. complex events: emotional narratives or social encounters

• Attentional focusing ensures that emotionally salient features of complex events are preferentially retained in memory - an evolutionary advance

• Amygdala lesion

  • Do not focus on “central gist” of information - when memory is testen for audiovisual narratives that describe emotionally arousing events

  • Valence is the crucial factor in engaging amygdala during emotional memory tasks

    • In some cases patients do preferentially remember words that are effectively valent, but low in arousal - relative to neutral ones

Memory modulation hypothesis

States that:

• Greater long-term memory for emotional than neutral events reflects the neuromodulatory influence of the amygdala on consolidation processes in MTL (medial temporal lobe) memory regions through engagement of stress hormones

  • E.g. supported by findings from research on rodents

• Emotional arousal does not simply strengthen memory - it modulates which information gets prioritized for LTM storage

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How amygdala modulates consolidation of memories during emotional arousing events:

• 1. When experiencing an emotionally arousing event, hormones (e.g. adrenaline and cortisol) are released

• 2. The hormonal signals influence the amygdala - by acting on the norepinephrine receptors - increasing its activity

• 3. The amygdala then modulates memory-related brain regions - e.g. hippocampus and sensory cortex - enhancing processes involved in memory and consolidation

  • The amygdala acts as a modulator - helping to strengthen the consolidation of memories formed during emotionally arousing events

E.g. Evidence showing effects of activation vs inhibited activation of amygdala on encoding and consolidation of emotional memories - important for the memory enhancing effects of emotion

• Healthy adults given a placebo 1h before the story, remember the emotionally arousing portion of the story better than the neutral portions 1 week later

• Proppranolol, blocks the adrenergic receptors, thereby reducing the effects of adrenaline and noradrenaline. Its administration during encoding abolishes the retention advantage (for emotionally arousing portion of the story) in healthy adults

• Two patients with selective amygdala damage (SM and BP) also lack the retention advantage

The role of amygdala during memory retrieval

Resent research in rodents suggests that the amygdala also contributes to the reconsolidation of emotional memory traces following their retrieval - not only encoding and consolidation stages of memory

• Dolcos et al. (2005)

  • Participants viewed neutral and emotional pictures - then returning 1 year later to perform a memory test:

    • Emotional pictures were remembered better than neutral ones - correlating with activity in amygdala and MTL memory regions

      • But only when participants indicated that they remembered (recollected) seeing the pictures 1 year ago

        • Recollection = retrieval of qualitative information (e.g. place time, perceptual, emotional details) about an event

          • Recollection is especially enhanced behaviourally by emotion

        • Familiarity = Feeling of having previously encountered something without the retrieval of any associated contextual details - (i.e. “knowing”)

    • Greater retrieval success activity was found in the amygdala, hippocampus and entorhinal cortex for emotional relative to neutral pictures.

      • In amygdala and hippocampus the activity was enhanced for emotional items recognized with a sense of recollection rather than familiarity

Fear conditioning - the role of the amygdala

How fear conditioning usually is measured in humans

• Skin conductance response (SCRs)

• Potentiation of eyeblink startle reflexes

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Neuroscientific research pointing to the importance of the amygdala in fear conditioning

• In rodents:

  • Lesions of the basolateral and central nuclei of the amygdala prevent the acquisition of fear to discrete cues and environmental contexts

  • During fear conditioning, electrophysiological changes occur in the lateral amygdala before they do in other brain regions

  • To extinguish fear behaviours, the ventromedial PFC suppresses amygdala function by engaging a network of inhibitory interneurons

• Double dissociation regarding the contributions of the amygdala and hippocampus to conditioned emotional learning in humans

  • Damage to the amygdala:

    • Consistently impairs fear conditioning and fear-potentiated startle responses

      • (similar to those observed in non-human animals)

  • By contrast, amnesic patients with damage restricted to the hippocampus show the opposite dissociation:

    • They can acquire conditioned fear on simple tasks but cannot verbalize the appropriate stimulus relationships

  • Important distinction between conditioned fear response and verbalizing stimulus relationships

    • Unlike rodents, humans acquire conscious knowledge of the stimulus relationships, which can modify learning under some circumstances

    • The evidence therefore show how declarative and non-declarative aspects of simple forms of fear learning are neurally dissociable

Contextual reinstatement of fear - the role of hippocampus

The contextual reinstatement of extinguished fear - hippocampal dependent

• (Although the initial acquisition of simple fear conditioning to sensory cues depends on the amygdala and not the hippocampus)

• Rodent lesion studies

  • Shown that: the integrity of the hippocampus is important for the contextual recovery of extinguished fear

• Amnesic patients with selective hippocampal damage

  • Do not show contextual fear reinstatement, despite acquiring fear normally

    • In contrast to non-amnesic persons!

      • Normally conditioned fear responses that have been extinguished can be recovered in a context-dependent manner

Post Traumatic Stress Disorder (PTSD) and emotion induced memory enhancement

Diagnostic criteria

• Exposure to a traumatic event

• Persistent re-experiencing of the traumatic event

• Persistent avoidance of reminders of the event

• Persistent symptoms of heightened arousal

• Duration of symptoms must be more than 1 month

• Significant impairment in social, occupational, or other important areas of functioning

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Reduced hippocampal volume correlating with months of combat exposure and development of PTSD

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PTSD and generalization (worsened memory discrimination)

• Memory discrimination serves to disambiguate new experiences from stored memories

• Upon experiencing a situation that shares features of a traumatic event:

  • Healthy individuals (non-PTSD):

    • Able to discriminate a novel experience from a fearful one and successfully encode the novel experience as novel and safe

  • PTSD individuals:

    • Excessive generalization manifests as a failure to discriminate the novel, safe ecperience from the previously stored emotional memory

      • Leading to excessive arousal and fear responses

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Psychopharmacological studies providing greater specificity about what phase of memory is affected by emotion

• Memory phases: encoding, consolidation, storage, retrieval

• Neurohormonal memory modulation in rodents:

  • Post-training infusion of β-adrenergic receptor antagonists into he basolateral amygdala blocks the memory-enhancing effects of adrenaline

  • While infusion of β-adrenergic receptor agonists facilitates memory consolidation

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Neuohormonal memory modulation in PTSD

• Beta-blockers are currently being evaluated as potential agents for secondary prevention of PTSD

  • Administration of the β-adrenergic receptor antagonist propranolol seems to selectively reduce memory consolidation for emotionally arousing material

    • i.e. similarly to the rodent study above

Adaptive forgetting and Inhibitory control - connect to PTSD

Adaptive forgetting and Inhibitory control

• May promote resilience by limiting the involuntary retrieval and emotional impact of trauma-related information

  • Allowing flexible control over attention and memory

• Evidence - think/no-think - can we inhibit a memory?

  • First, Training faze:

    • Learn to associate 40 pairs of pictures (a face and an item) to a precision level of 95%

  • Second, experiment faze:

    • Baseline:

      • 8 pairs that was previously trained on, will not be shown during this faze - is used as a control to see what you remember naturally without manipulation

    • Think:

      • 16 faces with green shown around them: instruction is to “think of the associated picture”

    • No-think:

      • 16 faces with red shown around them: instruction is to “not think of the associated picture”

  • Third, test:

    • Tested for all 40 pairs of pictures

  • Results:

    • Actively “think”ing gave better memory results than baseline

    • Actively inhibiting (no-think) gave worse memory results than baseline

      • PFC inhibiting hippocampus when asked not to think about something —> weakening hippocampus’ ability to recall the memory later

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Inhibitory control and PTSD

• Waldhauser et al. (2018) - trauma exposed refugees in Think/No-Think task

  • With PTSD showed poorer memory suppression than without PTSD

    • With PTSD - failed to downregulate gamma activity associated with the reactivation of sensory memory traces

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• Mary et al., (2020) - Paris terrorist attack survivors with and without PTSD

  • Without PTSD - had stronger PF control system (especially in right anterior dorsolateral PFC) - inhibiting memory-related brain activity

  • With PTSD had reduced PF control

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• Both studies show that PTSD may involve a general deficit in inhibitory control over memory

  • Contributing to difficulties in suppressing unwanted thoughts and memories