2. The Brain Flashcards
What does it mean to order the brain by phylogenetic division
Organizing the brain structures in terms of the order in which they are thought to have evolved
Phylogenetically, what are 3 main regions of the brain
Forebrain
Midbrain
Hindbrain
What are 3 structures in the hindbrain
Medulla
Pons
Cerebellum
What does the medulla do and where is it located
hindbrain
- transmits info from the spinal cord to the brain
- regulates life support functions like respiration/blood pressure/coughing/heart rate
think -> modulates [functions], medium [transport]
What does the cerebellum do and where is it located
hindbrain
- coordinates muscle activity
- balance, coordination
lesions cause damage to above + damage to ability to shift attention from visual and and auditory stimuli, and dealing with temporal stimuli like rhythm
cerebellum -> um -> mu -> muscle
bell -> balance
What do pons do and where is it located
hindbrain
- neural relay centre (cross over from left and right sides of the brain)
- balance + processing of visual/auditory info (kinda similar to cerebellum lesions??)
pons -> latin for bridge
What are 5 structures in the forebrain
thalamus
hypothalamus
hippocampus
amygdala
cerebrum (the entire upper wrinkly “casing” on forebrain)
Where is the thalamus located and its use
Forebrain
- switching station for sensory information
- involved memory
above the thalamus (like an overhead)
Where is the hypothalamus located and its use
Forebrain
- regulates basic biological functions (hunger, thirst, temperature, sexual arousal), by releasing hormones to control the pituitary gland
- involved in emotions
- homeostatic behaviours
hypo: beneath
Where is the hippocampus located and its use
Forebrain
- Learning
- Long term memory
- Emotions
Where is the Amygdala located and its use
Forebrain
- Memory, emotion, aggression
- Strength of emotional memories
- Emotional learning
Where is the basal ganglia and where is it located
Forebrain
- production of motor behaviour
gang -> beats people up
What are the four lobes of the cerebral cortex
Frontal
Parietal
Temporal (on sides)
Occipital
What is the cerebral cortex
Cerebral cortex is a layer in cerebrum consisting of neurons with white matter underneath that carries info between cortex and the thalamus or between different areas in the cortex
Explain the main functions of the parietal lobes
Contains the somatosensory cortex
- Processes sensory information from the body
- sensations of pain, pressure, touch, or temperature
- spatial processing and attention
Explain the main functions of the occipital lobes
Processes visual information
Explain the main functions of the temporal lobe
- Processes auditory information
- supports function associated with encoding and retrieval of info from LTM
What might damaging the temporal lobe affect
ability to process auditory information
memory: since the temporal lobe is right above the amygdala and hippocampus
What are the 3 regions of the frontal cortex and their uses
Motor cortex: Directs fine motor movement
Premotor cortex: Planning fine motor movements
Prefrontal cortex: executive functioning
What is the precentral gyrus
In the frontal lobe, stretches horizontally (wrinkle) across the center of the brain
contains the motor cortex
What does homeostasis mean
State of balance in the body needed to survive
What are the general functions of structures in the midbrain
- Relays information between brain regions
- Keeps us awake and alert
What did Franz Gall believe in and his student invent
He believed in Faculty Psychology: theory that different mental abilities were independent and carried out in different parts of the brain
student invented phrenology:
psychological strengths/weaknesses can be precisely correlated to the relative sizes of different brain areas
What are 2 erroneous assumptions with phrenology
- Size of a portion of the brain corresponded to its relative power
- Different faculties were absolutely independent
Where is and what is Wernicke’s area responsible for
left temporal lobe
damage causes fluent aphasia: speech is fluent in pitch and rhythm but makes no sense. patients also have difficulty understanding speech
What is Broca’s area responsible for
Left frontal lobe
damage causes nonfluent aphasia: person is unable to produce many words or speak very fluently
What does the Penfield cortical body map do
Maps the sensory and motor cortices of the brain
- organized sizewise based on amount of information received from that part of the body
What is brain ablation and what did Karl Lashley find after doing it to rats and seeing them run in a maze
Removal of parts of the brain
Found that the impairment was related to the total amount of the cortex removed, rather than the region -> showed higher order processes are too connected to be located in one region
What is the plasticity of the brain
Brain regions can adapt to take over the functions of damaged regions depending on the extensiveness and patient age
What does it mean for the brain to be lateralized
Different hemispheres of the brain play different roles for some cognitive functions, especially language
WRT lateralization, what roles/regions are each hemisphere “generally” found to take/are larger
Most (95%) of people have a specialization for language in the left hemisphere, and is larger in size (esp for language areas)
Usually right hemisphere has larger parietal and temporal areas
- speculated to have better integration of visual+auditory info and better spatial processing
What connects the two hemispheres
corpus callosum
What is a doule dissociation
Brain damage and behaviour for two cases are completely disassociated from each other, used in reasoning
etc. Broca’s area and Wernicke’s area
What are two static brain imaging techniques
CAT
MRI
What technique does CAT scans use, and what can it be used to determine in brain injuries?
Highly focused X-rays are passed through the body from different angles
Differing densities in the brain defect the X-rays differently
Can be used to determine area and age of the injury (presence blood for recent, spinal fluid for old)
What technique does MRI scans use?
Magnetism:
under a strong magnetic field, different tissues in the brain produce different signals
What are two brain activities that functional brain imaging depends on
- Electrical signals generated when neurons fire
- Metabolism/blood flow as a byproduct of 1
What are 3 reasons MRI scans preferred over CAT scans
- Requires no exposure to radiation
- More detailed images for structures
- Can also measure the functional aspects of the brain
What functional brain imaging technique depends on electrical signals
EEG (or ERP), MEG
What functional brain imaging techniques depend on measuring blood flow
PET
fMRI
What is EEG/ERP
When you attach a bunch of electrodes to areas of the scalp and measure the changes in electrical signals generated.
ERP: event related potential
- more specific segment of the continuous EEG recording
How does Positron Emission Teomography (PET) work?
Inject radioactively labelled compound that can be detected, and then measuring the blood flow to different parts of the brain
- depends on the fact that more active areas require more blood flow/uses more glucose
- uses radiation
How does fMRI scan work and what is it detecting?
Based on magnetism, and the fact that oxygenated and de-oxygenated blood have different magnetic properties
- heart is most magnetic?
detects the BOLD function
What is the substraction technique and how is it applied
It is used to isolate brain regions contributing to a specific cognitive process
Task state - Control state
What is the BOLD function and how is it used?
Blood Oxygenation Level Dependent Function
Total is about ~20 seconds
- first few seconds: receiving signal, so oxygenation dips as it is consumed
- afterwards: blood slowly inflows, and peaks at ~10-15 seconds
- after afterwards: dip back down to pre-signal state
detected by fMRI
