Week 21 Flashcards
1
Q
Emotion
A
- an internal process that modifies the way an organism responds to certain kinds of external stimuli
- feelings are our most salient version of emotions
- emotional situations arouse the autonomic nervous system (homeostasis between sympathetic and parasympathetic aspects; e.g. an emotional situation resulting in nausea may involve a sympathetic stimulation of the stomach and a parasympathetic stimulation of intestines and salivary glands)
2
Q
Common sense view of emotion
A
seeing danger –> leads to emotional fear response –> causes autonomic nervous system response (e.g. heart rate increase, sweating) –> fight or flight activated
3
Q
James-Lange Theory
A
- bottom-up theory of emotional experiences (that autonomic responses precede emotional feelings)
- sensory stimuli –> triggers changes in visceral organs (autonomic system) and skeletal muscles (somatic nervous system) –> increases heart rate and allows us to run away –> visceral + movement effectors trigger the feeling of fear
- predicts that people with weaker autonomic/muscular systems will feel less emotion + that increasing someone’s actions towards a situation should enhance their emotions
4
Q
Testing evidence related to J-L theory
A
- pure autonomic failure (failure of output from ANS to the body): patients do not have difficulty identifying emotions others might experience but they do feel emotion less intensely than before
- paralysis: unable to instigate any motor fight or flight behaviours but still repeat emotions to the same extent
- Botox: paralysis of the whole face has led to reduced emotional responses (supports relationship between muscular system and emotions)
- damage to PFC –> weak autonomic responses –> still normal subjective responses; compared to damage to somatosensory cortex –> normal autonomic responses –> little personal emotional experience (not an autonomic link)
- initiating an action can enhance an emotion: e.g. spontaneous rapid breathing may induce panic attacks; smiling has been shown to make you feel happier just by the action of it
- cutting peripheral nerve from muscles in rats and cats does not appear to affect emotions, although it cuts out autonomic responses
- removal of the cortex in cats led to spontaneous fight or flight responses (sham rage) not the complete loss of emotions –> suggests the hypothalamus is also involved in generating internal emotional experience + also that higher levels of processing are involved in emotional responses
- difficulty differentiating between actions (e.g. running towards = happiness but running away = fear)
5
Q
Cannon-Bard theory
A
- suggests that an emotional stimulus simultaneously triggers autonomic response and emotional experience
- ANS responds too slowly to account for rapid onset in emotional experience (e.g. blushing takes 15-30 seconds after the feeling of embarrassment)
- people generally have problems detecting changes in autonomic activity (e.g. you are not always consciously aware of changes in heart rate so how could this alter emotions)
- other things can initiate autonomic activity but does not initiate emotions (e.g. why do we not feel afraid when we have a fever)
- not enough unique patterns of autonomic activity to represent the array of unique emotional experiences we have
- argument from experiments is that sensory information is relayed to the thalamus where it then bifurcates to the amygdala (top-down to communicate) and some to they hypothalamus (controls bodily responses)
6
Q
Schacter & Singer Theory
A
- brings in a crucial cognitive element of emotions and the importance of brain processing
- still recognises the crucial involvement of bodily states in experiencing emotions
- experiments testing emotional responses in groups showed that the same response was observed in a control group as with an informed adrenaline-adminstered group; whereas the uninformed adrenaline group had a very strong emotional response (as they interpreted their change in physiological state differently even though it was the same in both)
7
Q
Lazarus Theory
A
- further emphasising the cognitive element that mediates emotional experience
- also including the impact of personal memory on shaping your emotional experience (affects interpretation of current situation and therefore influences emotional response)
8
Q
Feldman-Barret Theory
A
- emotions are under our control to some extent but they are also subject to our previous experiences
- therefore, creating new experiences to events could change our emotional responses quite significantly
- underlies the thinking behind CBT to treat emotional problems
9
Q
Brain areas associated with emotions
A
- the Limbic system is in the border between cortex and brainstem
- it includes the amygdala, hypothalamus, thalamus, hippocampus etc. as well as orbitofrontal and prefrontal cortex
- any emotional response appears to induce activation in aspects of the limbic system (e.g. negative emotions = activation in orbitofrontal and ventromedial cortex)
- activation of left frontal and temporal areas (associated with approach and behavioural activation system)
- activation of right frontal and temporal areas (associated with withdrawal, decreased activity and behavioural inhibition system)
- damage to ventromedial prefrontal cortex impairs ability to anticipate emotional consequences, alters responses to moral dilemmas and impairs decision making
- gustatory cortex neurons (in insular cortex and basal ganglia) that respond to unpleasant tastes also impact our ability to identify disgusted facial expressions and experience general disgust; also a much greater activation when the facial expression is obviously disgusted
10
Q
Amygdala
A
- overall the amygdala responds to ambiguity in emotional situations; as well as detecting the presence of emotional information, especially fear and threat
- receives input from pain, vision and hearing centres
- well suited for establishing conditioned responses (some cells respond to reward and others to punishment)
- projects into the hypothalamus which controls autonomic responses (e.g. blood pressure, heart rate etc.) and to the prefrontal cortex (that modulates behaviour); also to the midbrain –> pons (generates startle behaviour)
- when the amygdala is damaged, there is still a startle reflex but no link between fear and the conditioned stimulus (hence this is a key relay station)
- Toxoplasma gondii leads to amygdala damages –> rats no longer show fear when approaching cats (may be due to failure to interpret the emotional significance)
- Kluver-Bucy Syndrome: removal of the amygdala results in psychic blindness (inability to recognise the emotional significance of events)
- crucially, found that the amygdala is activated in cases of ambiguity (e.g. in facial expressions in a fearful situation - someone looking away fearfully is ambiguous as to what the threat is)
- Urbach-Wiethe Disease: accumulations of calcium in the amygdala and atrophies –> patients exhibit fearlessness (e.g. laughing at lifethreatening events) as well as failing to recognise fear in others (but can still recognise other emotions in them, just not fear!)
- amygdala responds more to fearful than happy eye whites, indicating a major link to fear responses –> then other brain areas (such as PFC) can further process emotion and bring in a personalised interpretation (e.g. inhibiting the amygdala is a scary face comes from a loved one)
11
Q
Attack and escape behaviours (testosterone)
A
- closely related to fight or flight responses in the sympathetic nervous system
- testosterone is linked with social dominance and aggression (e.g. higher levels of testosterone in violent crime)
- by injecting testosterone into women, it was found that this delayed conscious recognition of facial threat signals suggesting it may inhibit these social aggression cues and therefore lead to unnecessary crime and angry outbursts
12
Q
Attack and escape behaviours (serotonin)
A
- also shown link to low serotonin levels and aggressive behaviour
- high amino acid diets can block BBB channels for tryptophan needed to synthesise serotonin so this can lead to increased aggression
- similarly less active forms of tryptophan hydroxylase (enzyme that converts tryptophan into serotonin) leads to more aggression
- serotonin also linked to depression and impulsivity so may have more general effects of less serotonin –> less behavioural inhibition –> more aggression and other negative emotions
- also potential converse action as, during bursts of aggressive behaviour, the brain seems to release more serotonin which may magnify the behavioural response
13
Q
Visual processing
A
- signals coming from retina may come from magnocellular neurons (large receptive fields, encoding movement and large patterns), parvocellular neurons (small receptive fields, detects visual details and colours) or koniocellular neurons (mostly small receptive fields but this varies, multiple functions)
- from these neurons signals travel along the optic nerve
- 90% of axons connect to the LGN (in the thalamus)
- this connects directly to the primary visual cortex/V1 area
- remaining 10% of axons from the retina, via the optic nerve, connect to the pulvinar nucleus (thalamus) and superior colliculus (important in visual attention and connections to area V5)
14
Q
Organisation of the retina (inner layer)
A
- cones (detect colour and allow us to focus on fine detail)
- rods (become active only under low light conditions for night vision, more sensitive but only function in black and white)
- 120 million rods distributed across the retina except in the fovea
- only about 6 million cones which are densely packed in the fovea (visual acuity in the centre of your vision) and more sparsely distributed across the remainder
15
Q
Organisation of the retina (middle layer)
A
contains bipolar cells, which collect neural signals from the rods and cones and transmit them to the outermost layer
16
Q
Organisation of the retina (outer layer)
A
- contains retinal ganglion cells (sensory neurons) that form the optic nerve –> then pass signals to the brain, via the blindspot (that does not contain rods or cones)
- each RGC responds to light falling into its receptive field (i.e. any photoreceptors stimulated within there causes a change in firing rate of the neuron but causes lateral inhibition as some are excited and some inhibited)
- either on-centre or off-centre cells (defines the shape of objects through depicting the edges)
17
Q
Colour-opponent system
A
pairs of visual neurons work in opposition (e.g. red-green cells are excited in response to red wavelengths and inhibited in response to green)
18
Q
Light adaptation
A
- light first passes through the cornea, which bends the light wave and sends it through the pupil
- the iris controls the size of the pupil and therefore the amount of the light that can enter the eye
19
Q
Accommodation (in the eye)
A
- muscles in the eye control the shape of the lens to bend the light again and focus it onto the retina
- the muscles change the shape of the lens to focus objects at different distances
- nearby objects = rounder lens
- faraway objects = flatter lens
