Ramachandran and Eagleman Videos Flashcards
Prosopagnosia
When people are unable to recognize familiar faces including their close family members and even their own face. It occurs when the right fusiform gyrus (that controls facial perception and memory) in the brain is damaged.
Capgras Syndrome
When someone has a head injury or a tumour, comes out of a coma and seems perfectly normal (they can discuss politics, chemistry, calculus, etc.), but doesn’t recognize his wife or his mother as themselves. Well he recognizes them but there is no emotional response towards them and so he believes they are imposters. He thinks they are imposters; she looks like his mother but he thinks she is an imposter.
How does Ramachandran explain the cause of Capgras Syndrome?
Freudian psychology says something weird. (sexual attraction to mother)
He says there is a disconnection between the recognition of the person and the emotional connection (limbic system) that comes when recognizing that person. The wire between the emotion and visual processing is cut. That is why they recognize that they look like the person they know but think that they are an imposter.
When hearing his mother on the phone, he recognizes her but if she approaches her he thinks she is an imposter. There is a separate wire for the auditory and the visual cortex. The visual doesn’t trigger anything in the brain but when he hears his mother the auditory cortex hears her and it cascades into the limbic system and he emotionally responds and recognizes her.
How does Ramachandran explain Phantom Limb Syndrome?
Deep integration and complex pathways for touch in the brain with the motor system. The body’s touch systems and nerves are mapped in the brain. When an arm is amputated the nerves going to the hand are no longer there. But the nerves nearest it (for the face) cross-wire and overlap and the nerves in the hand take over and they feel pain, or itchiness in the phantom limb. When they scratch their face they feel the itch relieved.
You can help someone move their paralyzed phantom limb with a mirror in a box. You trick the visual part of the brain into thinking that the phantom limb is there when it’s just a reflection of your other arm. Then you can move the phantom limb again and eventually the pain goes away.
Mirror neurons
Mirror neurons fire in response to someone else’s stimulus, not when an actual touch or stimuli is happening.
Why are they called empathy neurons?
The pain neurons in someone’s brain will fire when they watch someone else in pain. No pain is being experienced but the signals still fire, in empathy for the person being viewed who is suffering.
How can we make use of mirror neurons to help relieve pain?
When someone’s phantom limb is hurting a lot, if another person massages their own limb, their mirror neurons fire and the pain in their phantom limb subsides.
Synesthesia
A person who is completely normal (2-3%), every time they see a number on a sheet of paper, they see a particular colour. (5 is red, 6 is yellow, 7 is indigo, etc.) But there are many different forms. Hearing sounds and seeing colours, tasting sounds, hearing certain words and feeling yourself getting poked, etc. Others have connections between the taste part of the brain and the colour part of the brain and when they eat foods they see many types of colours (Chicken, vanilla ice cream, and orange sauce). They only experience it in the mind’s eye. They know that it is not really there in space.
Many people with synesthesia are very used to it and enjoy it. They couldn’t imagine their lives without it.
How does Ramachandran explain synesthesia?
Number centre in the brain and the colour area in the brain are beside each other. They are touching in the brain and there is accidental cross-wiring in these people’s brains. The colour neutron is cross-activated every time a number is processed. As the brain matures it prunes away excess connections and is sculpted, and when the gene that controls that pruning mutates, the connection between numbers and colours stays present.
How many times more common is synesthesia in artists, poets, and novelists?
Eight times more common in artists, poets, and novelists. All these people have higher creativity and use metaphor much more than the average population. That makes them creative because they have more links in far-flung areas of the brain, and this allows them to make more connections in the world and be more creative.
According to Ramachandran, why don’t we all have synesthesia?
We don’t want everybody to be poetic or creative. We don’t want neuroscientists to get metaphorical on us; we need literal and analytical people too. The gene pool has selected for both in the population.
What part of the brain is involved in sequences?
The left hemisphere angular gyrus is involved in sequences. It is the size of your finger.
What is Dr. David Eagleman’s view of synesthesia and its cause?
Eagleman says that the amount of wiring in everyone’s brain is the same. He just thinks there is a slight difference in inhibition and excitation in certain people. Essentially Eagleman thinks there is less inhibition in synesthetes’ brains. He thinks this because synesthetes can experience synesthesia, meaning that we don’t have to be cross-wired. In the same way, synesthetes’ experiences of synesthesia can vary when they are tired or drunk.
