Wk3 - Fear Recognition Flashcards
What part of the brain is very important in emotion?
Amygdala
What is the amygdala important for?
Emotional face recognition
Emotional memory
Aspects of social-signalling
What changes does amygdala damage cause?
Changes in emotional and social behaviour
What is an example of social-signalling?
Watching people’s gaze
Does amygdala damage cause cognitive deficits? What does this suggest?
No
The amygdala is specialised to emotion
What process is the amygdala necessary for?
Fear recognition
What case study provides evidence for the amygdala’s role in fear recognition?
S.M
Also D.R and S.E
What condition did S.M have?
Bilateral destruction of the amygdala
What was not affected by S.M’s amygdala damage?
IQ. S.M had normal IQ.
Preserved ability to recognise and identify faces
What was affected by S.M’s amygdala damage?
S.M had a severe impairment specific for recognising fearful faces
Does amygdala damage affect facial recognition and facial identity?
No. Amygdala damage just affects fear recognition.
What did patients D.R and S.E contribute to our understanding of the amygdala’s role in fear recognition?
Patients can still understand the concept of fear, but they cannot recognise the fear emotion.
Is fear recognition a conscious or unconscious experience?
Can be either conscious or unconscious
What is the unconscious route of fear recognition?
Visual stimulus –> Superior colliculus –> Thalamus –> Amygdala
What is the conscious route of fear recognition?
Visual stimulus –> Thalamus –> Visual cortex –> Visual system/processing areas –> Amygdala
What is another name for the unconscious route of fear recognition?
The quick and dirty route
Can we respond to a fearful stimulus before we are consciously aware of it?
Yes - this is a clear evolutionary advantage
Which route of fear recognition is faster?
The unconscious route from a visual stimulus to the amygdala
Which route is the visual cortex involved in?
The conscious route of fear recognition from a visual stimulus to the amygdala
Why is the unconscious route faster than the conscious route of fear recognition?
The unconscious route bypasses the visual cortex loop. The information will go straight from the visual thalamus to the amygdala.
How does the amygdala activate fight/flight response mode?
Sends messages to increase heart rate, blood pressure, and activate muscles
In which route is the visual stimulus blurry?
Unconscious route
What is another word for blurry?
Low-frequency
How does the visual image differ between the conscious and unconscious routes?
Conscious route = clear, detailed image because it is processed through the visual cortex
Unconscious route = blurry, low-frequency image
What are the 2 distinct processing streams?
Conscious - goes to the amygdala via the visual cortex
Unconscious - goes to the amygdala straight from the visual thalamus
What are the 2 types of cells involved with the 2 visual pathways?
Magnocellular channels
Parvocellular channels
What spatial frequencies are magnocellular channels sensitive to?
Low spatial frequencies
What structures do magnocellular channels project to?
Sub-cortical structures
What is an example of a sub-cortical structure?
Thalamus, Amygdala
What spatial frequencies are parvocellular channels sensitive to?
High spatial frequencies
What structures do parvocellular channels project to?
Cortical structures (visual cortex)
Do parvocellular channels reach the amygdala?
No
Which channels project to the amygdala?
Magnocellular channels
Does a detailed image have a high or low spatial frequency?
High spatial frequency
In what circumstance can we achieve amygdala activation through images with just HIGH spatial frequency?
If the images go through the visual cortex in the longer, conscious route of visual processing
Do sub-cortical structures receive high spatial frequency input?
No
What experiment provides evidence for differentiation of spatial frequencies in visual processing?
Vuilleumier et al. (2003) - experiment using broad, high, and low spatial frequency images
What did Vuilleumier’s experiment find regarding activation in the visual cortex?
There was high activation in response to high spatial frequency images. This is expected because parvocellular channel input reaches cortical areas such as the visual cortex.
Some difference in response to low spatial frequency images.
No differentiation in response to fearful/neutral faces in high spatial frequency images.
What did Vuilleumier’s experiment find regarding activation in the amygdala?
There was a huge difference between amygdala activation in response to the fearful and neutral faces in the low spatial frequency.
Low spatial frequency selectively moves along magnocellular channels to the amygdala.
Where did Vuilleumier see most differential amygdala activation between fearful and neutral faces?
Low spatial frequency images
In the unconscious route, how does enhanced perceptual processing of visual threatening stimuli eventually come about?
The amygdala appears to send information back through projections to the visual cortex, in a feedback loop
How do we know that there is a feedback loop going on in the unconscious route in which the amygdala sends information back to the visual cortex?
Early ERP components show emotional modulation
Which spatial frequency images have a normal ERP in response to fearful face stimuli?
Broad spatial frequency (there is only slight increase in P1 for the fearful face compared to the neutral face)
What does a normal emotional modulation early ERP look like?
Sharp deflection at the P1 component. Goes up for the N2. Back for the P3 etc.
What does fear modulation look like on an ERP graph for high spatial frequency images?
No modulation of P1 in response to the fearful face - the lines for the fearful and neutral face are overlayed (the same)
What does fear modulation look like on an ERP graph for low spatial frequency images?
Large modulation of P1 component.
There is greater activation in response to fearful face than neutral face
We see the response happening EARLY. There is early visual processing.
What does early visual processing on an ERP indicate?
There is feedback going from the amygdala back to the visual cortex which increases a really early level of visual perception
There is a response to fear before there being a response to a face in general
What can we see from modulating the P100?
There is a response to fear before the person recognises that it is a face being shown
What is the face-specific component on an ERP?
N170
In fear recognition, does N170 or P100 come first? What does this indicate?
P100 comes first. Processing of fear comes before the processing of faces.
What causes the N170 face-specific component?
Activation in the fusiform gyrus
What is the fusiform gyrus selective to?
Selective processing of faces
What experiment shows us the effects of emotion on visual processing?
Fusiform gyrus activity and amygdala activity in attended versus unattended faces and fearful vs neutral faces
When was fusiform gyrus activity found to be greatest?
Attended, fearful faces
Which unattended faces gave greater fusiform gyrus activation?
Unattended fearful faces
What part of the brain did fearful faces activate?
Amygdala
Was the degree of amygdala activation modulated by attention?
No
Was an effect of attention or emotion found in this study of fusiform gyrus activity?
There was an effect of attention. Attended faces = higher fusiform gyrus activity.
There was also an effect of emotion. Fearful faces = greater activation than neutral faces.
Was there an interaction effect of attention and emotion on fusiform gyrus activity?
No.
What was found when this study of fusiform gyrus activity was repeated with patients with medial temporal lobe damage (affecting amygdala and hippocampus)
No difference in patients with hippocampal damage.
Patients with damaged amygdala did not show enhanced activation in the fusiform gyrus in response to fearful faces.
This confirms previous suggestions that the amygdala provides feedback to the visual cortex, thereby enhancing processing in the fusiform gyrus.
Can emotional stimuli enhance sensory processing?
Yes
What type of faces is visual cortical activation greater for?
Fearful faces
What causes enhanced sensory processing?
Feedback to the visual cortex from the amygdala. Increased amount of visual processing that is going on.
Why might we perceive something deeper if it is emotional?
Threatening stimulus –> amygdala feeds information back to the visual cortex –> enhances visual processing to a deeper degree –> more likely to remember the thing that is threatening in the future