# Brain Strucutre
![[lobes.png]]
- Related
- [[nervous-system]]
- [[lateralization]]
## Brain Matter
- We have the largest Brain-Body Ratio!
- 2% of total body weight
- Consumes 25% of the oxygen
- Consumes 70% of the glucose
- Consumes 25% of the nutrients
- 100% of brain is used!
![[cross-section-of-brain.png]]
- White matter
- Gives structure
- Delivers nutrients
- Provides communication
- Grey matter
- Computations happen here
- The fissures exist to fit as much as grey matter into the skull (increase
surface area)
![[neurons.png]]
- Neurons
- Synaptic - excitatory/inhibitory signal
![[distributed-processing-of-pain.png]]
- Feelings are processed distributed, e.g. pain
- Neural network is very tolerant to noise, as long as there are _enough_
neurons sending activation signals.
## Subcortical Regions
AKA "reptilian brain", we share this structure with reptiles.
![[brainstem.png]]
- Medulla - heart rate and blood pressure, basic house keeping
- Pons - regulates [[sleep]] cycle and alertness
- Midbrain - sex and aggression
![[cerebellum.png]]
- Cerebellum - regulates the smooth movement
![[limbic-system.png]]
- _Corpus callosum_ - major connection between the two spheres
- _Amygdala_ - our "spider sense", constantly looks for danger, the brain
structure that flips the "switch" for ==fight or flight response==
- _Hippocampus_ - episodic [[memory]], also memorizes what just happen right
before the danger
## Occipital Lobe
![[occipital-lobe.png]]
- LGN = lateral geniculate nucleus, a hub that **prioritizes** the sensory
signals
- Primary Visual Cortex
- Taking in the _raw input_ of [[vision]]
- _Scotoma_ is caused if damaged = seeing black spots
- Association Visual Cortex - recognizing the objects and interpretation
- Vision Agnosia - failed to interpret the vision information "The Man Who
Mistook His Wife for a Hat"
## Temporal Lobe
![[temporal-lobe.png]]
- _laterality_ = left vs. right
![[broca-and-wernicke-area.png]]
- Left brain - "analytical"
- Broca area -> related to speech. This area is connected to _motor strip_
- Wernicke area -> related to comprehension of speech
- Right brain - "creative"
- Tonal structure, pitch pattern, pitch interval, and timbre
## Parietal Lobe
- Motor cortex - movement
- Somatosensory cortex - somatic sensation
- ==_Contralateral Wiring_== - Left part of body processed in the right
hemisphere, and vice versa
- "Cortical Homunculus" created by Dr. Wilder Penfield (picture above)
![[sensory-homunculus.png]]
- The area on the brain => the importance of the body part, not the volume. e.g.
no feeling on elbow
- _Proprioception_ - the feeling of our body parts from inside - associated with
left brain - "whose leg is this!"
- Unilateral Visual Neglect - when left brain damaged, failed to notice the
right, and vice versa.
- Sensory Deprivation experiment - Our brain is hungry for sensory input, if you
don't feed it, it creates its own. (could this be related to [[meditation]]?)
## Frontal Lobe
- Makes half of the brain, and is the latest part. The shape of skull changed to
fit this part.
- The motor strip defines where the frontal lobe starts
- _Frontal lobotomy_ = severing the frontal lobe from the motor strip to
suppress aggression (used to be used to treat schizophrenia, bipolar, and
epilepsy)
- Slow thoughts, loss of spontaneity
- Perseveration Errors = don't shift the strategy when things change
- Loss of self-awareness, _flat affect_, lack of emotion, loss of empathy
- Deficiency of planning
- Tendency to confabulate = lying but not deceiving, producing stories
(confabulation in [[hypnosis]]?)