Flashcards in Emotion Deck (21)
emotions as response patterns
Emotion has 3 categories:
Central and peripheral nervous system
that translates sensory to voluntary muscular movement
portion of the nervous system that translates sensory into physiological process.
Symapthetic = excitatory
Parasympathetic = inhibitory
Voluntary skeletal muscles are organised in opposing pairs.
Neurons connected to muscle groups
The somatic and autonomic nervous systems can be distinguished by their anatomical organisation.
Whereas the somatic nervous system connects external sensory organs through the brain to muscles (red), the autonomic nervous system connects the brain to the organs and glands (blue).
Organs that secrete hormones regulating brain and physiology.
Hormones are like neurotransmitters but spread diffusely throughout the body and brain to modulate activity levels across of a variety of organs and neurons by coupling to receptors on those targets.
They are involuntary and regulated by the autonomic nervous system.
- Can gain conscious control
Hypothalamus and pituitary = master glands
Sympathetic and Parasympathetic ANS can be distinguished by their anatomical arrangements.
Sympathetic nerves - thoracic and lumber spinal cord – excitation
Parasympathetic nerves - cranial nerves (project directly out of the brainstem) and sacral spinal cord.
Spinal injury – damage to one side – may be more excitatory/inhibitory
Cranial nerves emerge directly from the brainstem (collectively the pons, medulla and midbrain).
The 12 cranial nerves (labelled I-XII) may be sensory or motor or mixed.
Those labelled A play a role in the autonomic NS controlling organs and glands.
The rest are part of the somatic NS.
Sensory – come from the sense
Motor – involved in generation of voluntary motor action within face and neck
A – change physiological state
mechanical things – heart, liver, lungs
produce hormones and imp for communication systems
Hypothalamus is the master endocrine gland.
Controls the pituitary gland to release hormones into the blood stream via the circle of Willis, to act on receptors on endocrine gland and major organs to change physiological state.
Hormonal outflow from pituitary complex and lots of permutations can take
Hypothalamus uses ‘hypothalamic releasing factors’ to control pituitary.
Pituitary releases 9 know hormones which act on different endocrine glands, to change their function and hormonal output.
Each Endocrine gland has a range of hormones.
Illustrates the complexity of physiological parameters underpinning emotion.
Cascade of hormonal events can be many and varied and controlled by hypothalamus
hypothalamus ANS master
Hypothalamus receives diverse input from the rest of the brain, and has nerve projections broadly into the somatic and autonomic nervous system, as well as controlling circulating hormones from the pituitary.
Hypothalamus is a cluster of diff nuclei
Channel that connects higher parts of the brain
The amygdala receives sensory information from the cortex, thalamus and hippocampus.
Detection of emotionally salient stimuli translated into somatic emotion via the striatum, increases sensory and motor signal flow via thalamus, increased arousal via brainstem, autonomic activity via hypothalamus
Important for fear and neg emotions
Equally imp for pos emotions, appetite, sexual interest, joy
Thalamus = projection site into cortex
Receives sensory info from all over cortex, thalamus, hippocampal formation
Outflow – filter and decide which sensory info need to have emotional reaction to
Ties emotionally relevant stim with emotionally relevant response – via ventral striatum – somatic component
Can also change processing of info up and down spine
Can have effects on ANS via projections to hypothalamus
Amygdala projects widely to a range of nuclei which produce specific aspects of emotional response
Amygdala lesions abolish emotional responses – somatic, autonomic and hormonal aspects.
Stimulation produces emotional reactions encompassing somatic, autonomic and hormonal aspects.
amygdala - Campese et al. (2015)
Conditioning of a tone to predict shock enables the tone to elicit a conditioned freezing (fear) response – emotional reaction
Lesions of the amygdala abolish conditioned fear indicating that it is the region mediating fear learning to previously neutral stimuli.
Sensory info into amygdala from shock detector – hard wired connections with freezing response – don’t need to learn
Have to learn tone is predictor of shock – also into amygdala
Synapse can be adapted through Hebbian learning
Contingency between CS and US = synapse strengthened
Amygdala-VMPFC - Phelps et al. (2004)
In humans, the magnitude of a fear CR (GSR) to a shock paired CS+ is correlated with amygdala activation to the CS+.
Extinction of the CS+ (presentation without shock) results in a decline in the CR.
Extinction learning was correlated with activation of the VMPFC in response to the CS+.
Shock Ps in scanner
GSR – tone = think shock will happen – fingers sweat
Magnitude of conditioned response in GSR to CS predicted by level to which amygdala activated by tone
Present tone but no shock – activation of VMPFC correlates with success which show extinction – ability to unlearn conditioned emotional response – how much VMPFC activated by CS
amygdala-VMPFC (OFC) - Schoenbaum et al. (2007)
VMPFC and orbitofrontal cortex (OFC) can be used interchangeably.
The role of the frontal cortex in extinction learning could be due to it exerting inhibitory control over the amygdala, it may be quicker at adapting to changes in contingency and override the amygdala (faster at learning), or it may encode the expected outcome to-be-compared with the actual outcome to generate a prediction error signal, i.e. when expectations are defied, which drives teaching signals (DA and 5HT) to modify associative learning in the amygdala.
Evidence supports the latter position.
Inhibit amygdala – old model of how brain works
anger and aggression - Manuck et al. (1998)
Human aggression and impulsivity are associated with reduced 5-HT (serotonin).
This association has been found in assault, arson, murder, child beating, personality disordered patients, alcoholics, adolescents with disruptive behavior disorders and a history of fire setting and unpremeditated homicide among incarcerated adult offenders.
Aggressive acts are species specific
anger and aggression
In primates, low levels of serotonin are prospective risk factor for being dead at time 2 (presumably due to aggressive/risky behaviour)
anger and aggression - Hornak et al. (2004)
How to connect VMPFC (OFC) and 5-HT in a theory of aggression.
Humans with bilateral lesions to the OFC cannot switch choice when it ceases to payoff, showing perseveration in a reversal task.
Fits with the view that the OFC encodes the expected outcome, to be compared to the actual outcome, to generate a prediction error signal which modifies learning.
Diff images – one more like to get paid money and other more likely to lose money
Learn to press correct images
Then reverse contingency
Should see dip and realise losses and switch strategy
Bilateral damage to OFC – learn initial correct start – but don’t change strat – perseveration
Losing more than should – drives teaching strat
anger and aggression - Schoenbaum et al. (2007)
In Schoenbaum’s model, the discrepancy between the expected and actual outcome is calculated by the dopamine and 5-HT neurotransmitter systems, to modify learning.
Low 5-HT would weaken this learning.
Low 5-HT may produce aggression and impulsivity because such individuals fail to learn to modify their aggressive behaviour when it produces no payoff.
Haven’t got outflow from prediction error – stuck with aggressive pattern of behav
laterality of emotions
The right hemisphere appears to play a more important role than left hemisphere in recognition of emotion.
Borod et al. (1998) found that patients with right hemisphere damage were less able to identify emotional faces or words than patients with left hemisphere damage. Left damage was the same as controls.
Not switched off from doing task as can still discriminate
Adolphs et al. (2000) tested the ability of 108 patient with focal brain damage to recognize emotional faces.
The heat map shows that poorer recognition of emotional facial expressions was correlated with damage to somatosensory cortex of the right but not left hemisphere.
mirror neuron hyp
neurons in the somatosensory cortex which respond to the person producing particular facial expressions also respond to someone else producing those same facial expressions.
Shows that the right somatosensory strip is activated by the concept of an emotional expression, irrespective of its source
Neurons controlling emotional recognition and expression are linked.
Supported by automatic mimicry of facial expressions by infants.
Babies cannot see their own face in a mirror, so how do they know that their expression corresponds with their mother’s? – only has sensory feedback from face to tell them what they’re doing
Neurons for recognition must be connected to neurons controlling expression.
Hardwired link between somatosensory and motor cortex?