Chapter 2 Flashcards
(69 cards)
1
Q
Stimuli help the brain:
A
- Orient the body
- Direct it to produce appropriate behaviour
2
Q
What do sensory organs do?
A
- Gather info about the world
- Convert info into biological activity
- This constructs perceptions (how we feel)
3
Q
Subjective differences in the brain allow species to do what?
A
Exploit different features in the environment
4
Q
What are adaptations?
A
Helped species form a view of the world that helped it survive
5
Q
What does the concept “the brain is plastic” mean?
A
- Neural tissue can change how it is organized based on the world around it
- Neuronal connections are constantly changing in response to experience
6
Q
Culture plays a ——- role in shaping our behaviour
A
Dominant
7
Q
What is neuroplasticity?
A
- The NS capacity to physically or chemically alter itself in response to its environment
- Capacity to compensate for injury and age-related changes
8
Q
What is phenotypic plasticity?
A
-Capacity to develop phenotypes which are observable characteristics
9
Q
A specific phenotype gets elicited through —– & ——
A
interaction between genotype & environment
10
Q
Do epigenetic factors change genes?
A
No but they influence how genetic factors are expressed through parental inheritance
11
Q
Describe the anatomical organization of the NS:
A
- NS is divided into Central & Peripheral systems
- The CNS is comprised of brain & spinal cord
- The PNS is comprised of –> all the nerve fibres & neurons outside of the brain & spinal cord.
- Carries sensory info into the CNS & carries back motor instructions from the CNS to muscles & tissues
- PNS Made up of: (Think of “Side of SEA”)
- Somatic (cranial & spinal nerves)
- Autonomic (sympathetic & parasympathetic divisions)
- Enteric systems
12
Q
Describe the functional organization of the NS:
A
- Somatic (transmit sensation, produces movement)–> gather info for the CNS & convey its message to move muscles in the body
- Autonomic (balances internal functions)–> allows the CNS to govern the body’s internal organs e.g heartbeat, urination etc.–> parasympathetic creates rest & digest response by calming nerves while sympathetic creates the fight or flight response by arousing nerves
- Enteric (controls the gut)–> controls digestion & stomach contractions by communicating with the CNS through the ANS; still autonomous
13
Q
What are the 2 directional flows of neural information?
A
Afferent–> incoming sensory information from the CNS
Efferent–>outgoing information that leaves the CNS
14
Q
What are the 3 orientations of the brain?
A
1) Anatomical–> direction of a cut from viewer’s perspective
2) Brain-body–> location from a frame of reference of the human face
3) Spatial–> location in relation to other body parts
15
Q
Name the 3 components of meninges (protective coverings of the brain):
A
1) Dura mater “hard mother”–> tough fibrous tissue attached to skull. Loose sac around the brain & spinal cord
2) Arachnoid layer “Spider’s web”–> super thin sheet of connective tissue following brain’s contours
3) Pia mater “soft mother”–> moderately tough membrane of connective tissue clinging to brain’s surface.
16
Q
What is the cerebrospinal fluid & where is it located?
A
- Between Arachnoid layer & Pia mater
- Provides cushioning for the brain so it can move without pressing on skull
- A colourless solution made up of ions (e.g sodium & chloride)
17
Q
What is meningitis?
A
Infection of CSF & meninges
18
Q
What is the cerebral cortex & where is it located?
A
-Folded & layered tissue in outer forebrain
-cortex means “bark” covers most of the brain; also called the brain’s surface
-80% of human brain overall
-Has expanded most through evolution
-Has 2 hemispheres (L/R) & 4 lobes P-O-F-T parietal, occipital, frontal & temporal )
-Right fist maps the orientation:
(Thumb for Temporal, Fingers for Frontal, Knuckles that you use to Punch for Parietal, Wrist that is Occupied for Occipital)
19
Q
What does each of the lobes do?
A
- Temporal–>Hearing, language, music, facial recognition, emotional processing (use your thumb to have thumb puppets that talk, argue, listen & you draw faces on them)
- Frontal–>Executive functions e.g decision making & voluntary movement (how you use your fingers to make legs that walk & point)
- Parietal–> Goal-directed movement & task performance (punching people moves them to the right direction)
- Occipital–> Visual scene processing (Illuminati eye sign on writst)
20
Q
What is the cerebrum?
A
- A major part of the forebrain constituting the L & R hemispheres
- Cerebellum means “little brain”, is under cerebrum & makes up the rest of the brain
21
Q
Describe the “bumps & cracks” visible from the brain’s surface:
A
- Gyri or gyrus (rhymes with “Cyrus” who had a bumpy career) are the bumps–> small protrusions formed by the folding of the cerebral cortex
- Sulci or sulcus (like a “succubi” that suck you dry & leave you empty like a crack) are the cracks in neocortex or cerebellum
- Gyri & sulci patterns are different across species
- Small brains (i.e rats) smooth brain with no bumps or cracks
- Big brains (i.e cats) have a longitudinal gyri
22
Q
What are 2 types of fissure (deep sulci)?
A
- Longitudinal fissure–> runs along the sides of the brain
- Central sulcus–> runs across the top of the cerebrum
23
Q
Describe the process of cerebral circulation
A
-Cerebral arteries wrap around the brainstem, cerebrum & cerebellum–> penetrate the cerebral cortex to nourish inner regions
Arteries–> feed blood to brain & send it back to the kidneys & lungs for cleaning & oxygenation through the veins
24
Q
Name 3 major arteries that send blood to cerebrum:
A
Anterior, middle & posterior cerebral arteries
25
Describe a stroke:
- Blockage or break in a cerebral artery which reduces blood flow, causes neurological symptoms & leads to the death of the affected region
- Depending on the artery affected, different brain region may be disrupted
- Brain's connections are crossed--> opposite side of the body from stroke region is affected
26
Describe the brain's internal features (not homogeneous):
Dark regions are grey matter-->composed of cell bodies & capillary blood vessels; in which neurons collect, modify & send information
-(Think of a butterfly in a grey Tim Burton movie flying over dead bodies that are being collected, chopped into smaller pieces and sent to the morgue)
Light regions are white matter --> composed of nerve fibres covered by fatty myelin sheaths that form long-distance connections between brain's neurons
-(Think of a nervous grandma in a fat white coat that is making long-distance calls to all her friends from other countries to stay connected)
Wing-shaped cavities are Ventricles-->
All 4 ventricles are lined with a network of blood vessels called choroid plexus
The ventricles are connected so that CSF flows between them
CSF is absorbed & deposited into the venous bloodstream through the lower layers of the meninges.
CSF eventually goes into the cerebral aqueduct which is a canal running down the spinal cord.
-(Think of a churro-eating pegasus is flying around 4 connected rivers and gets meningitis & eventually runs down a waterfall called Aquitart)
27
What are some of the vital brain functions performed by the CSF?
- Brain suspender-->so that it acts like it's 1/30 of its actual mass
- Shock absorber-->protects the brain from blows to the head
- Brain stabilizer-->Provides a stable environment for the brain through its chemical content; if unbalanced, can cause dizziness & fainting
28
The brain produces & distributes ----- ML of CSF per hour, accounting for ---- of its total volume.
25ML of CFS per hour, accounting for 1/5 of its total volume
29
What is the corpus callosum?
-A long band of white matter along the cerebral hemispheres containing 200 mil nerve fibres join 2 hemispheres & facilitate communication between them.
(Think of a white headband with CC written on it, it's got 200 mil diamonds on it & everyone is talking about it)
30
How do cortical & subcortical regions of the brain communicate during threat?
-Cortical area perceives a threat & lets the subcortical area know that they have already begun increasing breathing & heart rate via Sympathetic NS
(Think of upstairs neighbours letting downstairs neighbours know that they are blasting music & dancing)
31
What are two parts of the brain that are asymmetrical? What are 2 that are symmetrical?
-Planum temporale (understanding speech; L hemisphere is larger)
(Think of the saying "what planet are you from?" because you don't understand alien language)
-Heschl's gyrus (analyzing music; R hemisphere larger)
(Think of "Heechul's guy friends" analyzing his music)
-3rd & 4th ventricles & pineal gland are symmetrical
(Think of "pi= 3.14")
32
What are the two main types of cells in the brain?
Neurons--> carry out brain's communicative & info processing functions
Glial cells (also called astrocyte; looks like a star)--> modulate neuron activities
33
Describe what axons are:
-Axons connect neurons together & form nerves or tracts
( Think of Axe spray bringing people together)
Tract--> collection of nerve fibres in CNS & spinal cord (e.g path from the cerebral cortex to spinal cord is the corticospinal tract)
Nerves--> bundles of fibres outside the CNS (e.g path from eye to brain is the optic nerve)
(Think of "Inside tract vs. outside nerve")
34
What are brain similarities between animals & humans?
-Spinal cord & brainstem of fishes & amphibians, the neocortex of mammals, bilaterally symmetrical NS of worms.
35
How do the 3 brain regions develop in a vertebrate embryo?
- NS begins as a sheet of cells that fold into a hollow tube with 3 regions: Forebrain, Midbrain, Hindbrain
- This 3-part structure is equivalent to the adult brain of fishes, amphibians & reptiles
36
What are the 3 brain divisions & their subdivisions?
1) Pros-encephalon (front brain)--> Responsible for olfactions (smell)
Die-encephalon (between brain)
Tel-encephalon (end brain)
PRO (pro athletes always smell)
Die-Bet, Tel-it-to-End
2) Mes-encephalon (middle brain)--> Responsible for vision & hearing
MESsy MInd (we're messing up our vision & hearing)
3) Rhomb-encephalon-->Responsible for movement & balance
Met-encephalon (across brain; cerebellum)
Myel-encephalon (spinal brain; spinal cord)
RHOMBus (Rhombus can balance on each surface & be moved around)
Met-Across-the-hall
My-Space
37
Describe Florito & Scotto's Octopus study:
-Observer octopus watches Demonstrater octopus from an adjacent tank through a transparent wall
-Demonstrator is conditioned to associate red ball with reward & white ball with weak shock
-Demonstrator learned quickly to distinguish between coloured balls
-When placed in isolation, Observer also selected same object as Demonstrator, performed task correctly for 5 days without error.
Conclusion: Invertebrates display intelligent behaviour i.e learning through observation
38
What are the 3 major components of the CNS?
Spinal cord, brainstem & forebrain
39
Describe the spinal cord:
- Executes most of the body movements as instructed by the brain or independently via Somatic NS
- Each spinal segment sends out commands to an area of the body that they receive info from
- As part of the Somatic NS, spinal nerves carry info to the cord on behalf of skin, muscles etc. & send motor instructions back to control muscles
- The spinal reflex is automatic
40
What does the saying "afferent before efferent" mean?
Sensory signals enter the brain before an outgoing signal results in motor response
41
Describe the brainstem and its subregions:
- Begins where the spinal cord enters skull--> extends upwards into lower area of the forebrain
- Afferent signals from senses come in, efferent signals go out to spinal cord to control movement
- Each region performs 1+ tasks & all 3 regions have both sensory & motor functions
-Divided into:
Hindbrain--> long & thick --> important in motor functions (Think of a juicy chicken leg that used to run) extension of the spinal cord along with midbrain
Midbrain--> short & compact--> important in sensory functions (Think of the patty in the middle of a burger that takes over your senses)
Diencephalon-->Bulbous--> integrative sensorimotor tasks (Think of the word "circle" in Farsi that ties everything together) borders the brain's upper & lower parts
42
Describe the Hindbrain & its subparts:
- Controls motor functions (breathing, balance, fine movements etc.)
- Cerebellum as its most distinctive structure with its size depending on speed & dexterity of the species
- Sloth has a small cerebellum--> slow
- Cat has a large cerebellum--> fast
- Apes can expand their cerebellum size with increased cognitive capacity
- Reticular Formation--> "Net" Netlike mixture of gray & white matter. Nuclei localized into small patches along the length with specialized functions in stimulating the forebrain
- Pons-->"Bridge" Forms a bridge from the cerebellum to the rest of the brain
- Medulla--> "Vital" Regulates vital functions i.e breathing (which is why a blow to the back of the head can cause you to stop breathing)
(Think of HI-->Court Retour Pour Medschool)
43
Describe the midbrain & its subparts:
- Tectum--> Sensory component (roof, dorsal, posterior)
- Receives sensory information from the eyes & ears
- The optic nerve sends input to the superior colliculus
- The auditory pathways send input to the inferior colliculus
- The colliculi process sensory function & produce orienting movements
(Think of seeing being "superior" to hearing that is "inferior")
-Tegmentum-->Motor component (floor, ventral, anterior)
-Composed of many nuclei with movement-related functions
Tegmental nuclei:
-The red nucleus--> limb movement control (Think of "red dress" emoji)
-Substantia nigra--> movement initiation (Parkinson disease)
-Periaqueductal grey matter-(PGM)-> species-typical behaviours (Think of "BDSM")
(Think of "The Red Nigga Preferred Grey Material)
44
Describe the Diencephalon & its subparts:
Integrates sensory & motor information on its way to the cerebral cortex
Subparts:
1) Hypothalamus
- Below the thalamus, composed of 22 small nuclei & fibre systems, 0.3% of the brain's weight.
- Controls hormone production by interacting with the pituitary gland
- Takes part in all aspects of behaviour
(Think of being "Hyper Hormonal so take Pity on me")
2) Thalamus
- Bigger than hypothalamus, one in each hemisphere; left of brainstem's tip.
- Organizes & integrates sensory information to the cerebral cortex
- Routes to thalamus might be indirect
- Analogous sensory regions receive auditory & tactile info to be relayed to respective cortical regions in each hemisphere
- Other thalamic regions with motor functions receive input & relay it to the neocortex for movement planning
(Think of "Thalala being Sensitive")
45
Describe the forebrain & its subparts:
-Largest & most recently evolved region of the brain
Supbparts:
1) Cerebral cortex--> regulates mental activities (i.e perception, planning, emotions, memory)
2) Basal Ganglia--> control voluntary movement & role in cognitive fuction
(Think of "Gangs voluntarily moving together")
46
What is the allocortex & the neocortex?
-Allocortex "other bark" refers to both the 3 & 4 layered cortex
-Role in motivation & emotion control & certain kinds of memory
(Think of "Getting emotionally burned so put some Aloe on it but I should remember to buy it)
- Neocortex "new bark" is the tissue visible from outside the brain; unique to mammals
- Constructs & responds to a perceptual world
(Think of "Neo from the matrix fighting the constructed world")
-Together, neocortex & allocortex make up the cortex
47
What are the major parts of the allocortex?
Hippocampus
-Consolidation of ST into LT memories
-Verbal & Spatial navigation
(Think of "Hippo-Compass" can't remember where to go")
Part of the amygdala
-Regulates anxiety & fear
-Cat with amygdala removed will have no inhibitions
(Think of "Myg rhyming with Wig of a scary witch")
Cingulate cortex
-Emotion formation, learning, memory & linking behavioural outcomes to motivation
(Think of a "Single" lady feeling emotional about breakup, learning from mistakes, remembering good times & being motivated to do better)
Olfactory system
-Odour-detecting, small yet sensitive olfactory bulbs lie on the base of forebrain--> connect to nasal cavity receptors-->send input to pyriform cortex-->input goes to amygdala & dorsomedial thalamus-->frontal cortex
(Think of "Olaf small & sensitive sticking a carrot up your nose which then lights on fire, snatching your "wig" and shooting in up through door at the front" )
- Unique because it is almost entirely a forebrain structure while other sensory systems project most of their input to the midbrain & thalamus
- One of the first senses to evolve in animals
48
Describe the limbic system
- Originally thought to play a role in sexuality by Freud
| - Scientists can't agree on what should be considered part of the system
49
What is the vomeronasal organ (VNO)?
-Pheromone-detecting neurons--> project to olfactory bulb--> connects to amygdala--> hypothalamus
-Role of reproduction and social behaviour
(Think of "ABO"? more like "Very NO")
50
What are neocortical layers?
- 6 layers of grey matter are on top of the corpus callosum (joins the two hemispheres & helps them communicate)
1) Diff layers have diff types of cells
2) Each layer has a diff cell density (no cells in top layer 1--> packed cells in layer 4)
3) Diff layers have diff appearance
-Layer 4 is thick in sensory cortex & thin in motor cortex due to afferent sensory information
(Think of "At 4, I sense a thick boar, at 5-6 I'll sense some sticks")
- Layer 5 & 6 are conversely thick in motor neocortex & thin in sensory neocortex due to efferent motor information
- Sensory regions have large input layers & motor regions have large output layers according to cytoarchitectonic maps developed by Brodmann
51
What is a major difference between neocortex organization and other brain parts?
- Larger range of connections (connected to virtually all brain parts)
- The neocortex is the ultimate meddler that takes part in everything (Think of "neo flying everywhere")
52
Describe cranial nerves:
-Form part of the somatic NS
-Can have afferent sensory functions (i.e sensory inputs to the brain from eyes, ears etc.) by providing input to the brain from sensory organs
Can have efferent motor functions (i.e motor control of facial muscles) by connecting brain to internal organs
-Some have both sensory & motor functions
-one set of 12 controls L side of the head, the other set controls R side
53
Describe spinal nerves:
-For the optic, auditory & olfactory nerve, the spinal cord lies inside the bony spinal column made up of vertebrae
-Categorized into 5 regions from top to bottom:
Cervical, Thoracic, Lumbar, Sacral, Coccygeal
(Think of "Serve Thor Lunch by Sacrificing Cocks")
-The corresponding spinal cord segment in each region is their mini-brain
-Our body segments correspond to spinal cord segments
54
What are dermatomes?
- Means "Skin cut" and represents body segments
- Has a sensory nerve sending info from skin/joints/muscles to the spinal cord
- Has a motor nerve sending info to muscles for movement control
- These nerves are called spinal (peripheral) nerves & are functionally equivalent to cranial nerves in the head except that they take care of the rest of the body outside of the head/face
55
What is the somatic nervous system?
- Bilateral (2-sided) like the CNS
- The spinal nerves on L side of cord control L body
- The spinal nerves on R side of cord control R body
- Posterior fibres are afferent (carry information IN) & their gathering before entering a spinal cord segment is called posterior root. Posterior tracks are sensory
- Anterior fibres are efferent (carry information OUT) & their gathering before exiting the spinal cord is called anterior root. Anterior tracks are motor.
(Think of "Anticipation for a post that goes outward & resulting Post that comes inwards to your house")
56
What is the law of Bell and Magendie?
Law of posterior spinal cord being sensory & anterior being motor.
57
How do spinal functions integrate?
- Must coordinate inputs & outputs so they are interconnected in order for adjacent segments to operate together
- Integration of spinal cord activity does not require the brain's participation, hence the headless chicken running around
- Brain & spinal cord are still intimately connected in their CNS functions
58
Describe the autonomic nervous system:
-Regulates internal organs & glands via connections to the
SNS to the CNS
-Must keep working during sleep to sustain life
-ANS is affected by conscious states e.g stress
-ANS connections are ipsilateral (same side) just like SNS
-Has two opposing divisions:
Sympathetic division--> Arouses body for action (i.e increase heart rate, inhibit digestion, fight-flight response)
Parasympathetic division--> Calms the body down (rest & digest)
The sympathetic division is connected to the spinal cord which is connected to the ganglia (Think of "Gang of sympathizers")
- The autonomic control center that controls internal organs & is their min-brain
- The sympathetic ganglia are near the spinal cord on each side; looks like parallel-running chains
The parasympathetic division is also connected to the spinal cord's sacral region & the 3 cranial nerves:
- Vagus (calms internal organs) (Think of "calm veggie")
- Facial (control salivation) (Think of " facial drooling")
- Oculomotor (pupil dilation) (Think of"Occu=eyes")
- The parasympathetic ganglia are near target organs
(Think of "Paranormal activity being Very Far Out")
59
Describe the enteric nervous system:
- Called the "Second brain" as it has a wide range of neuron types & complex circuits, same chemical transmitter & lots of glial cells
- Considered part of the autonomic NS but is largely independent
- ENS neurons are in a sheet of tissue (plexus) that lines the esophagus, stomach, small intestine & colon
- These neurons form ganglia that send info to ANS & CNS through vagus nerve to control gut function
- Control bowel motility, secretion & blood flow--> permit fluid & nutrient absorption--> support waste elimination
- Behavioural disorders, stress & anxiety modify gut function (i.e nausea & diarrhea)
-Interacts with gut bacteria (microbiome) which influences nutrient absorption & regulate an array of psychophysiological processes--> inspired development of Psychobiotics
60
What is the first principle of the NS function?
1) NS produces movement in brain-constructed perception world
- Behaviour produced by the brain is directly related to the world constructed by the brain
- Mental representations depend on how your NS is structured, the info sent to the brain, & your previous experiences
61
What is the second principle of the NS function?
2) Neuroplasticity is the hallmark of NS functioning
- Experience alters the brain's functioning & is requisite to learning & memory
- NS stores info only if neural connections change & larger brains have more capacity for change, showing more plasticity
- Plasticity helps the brain recover from injuries & compensates for developmental abnormalities
- Examples of pathological neuroplasticity--> pain, epilepsy & dementia
62
What is the third principle of the NS function?
3) Many brain circuits are crossed
-Serve the opposite side of the body; one side receives the input but the other side is controlled
-Stroke to the left hemisphere---> difficulty sensing stimulation in the right
-Corpus callosum (Think of "Plus & Sum) is the connecting cable between the hemispheres
-4 exceptions to the crossed-circuit rule; showing ipsilateral formation:
1) Olfactory sensation
2) Somatic PNS
3) Autonomic PNS
4) Enteric PNS connections
(Think of "SEAO")
63
What is the fourth principle of the NS function?
4) CNS functions on multiple levels
- New brain areas add new levels of NS control
- New levels are not autonomous but integrated into existing neural systems creating a more elaborate form of control
- Mammalian evolution allowed for increased capacity to represent the world
64
What is the fifth principle of the NS function?
5) The brain is symmetrical & asymmetrical
- L/R hemispheres have some dissimilar features
- Cortical asymmetry is essential for integrative tasks (language, body control etc.)
- Language control is on the left side, spatial functions are on the right
65
What is the sixth principle of the NS function?
6) Brain systems are organized hierarchically & in parallel
- The brain has both hierarchical & parallel circuitry
- Hierarchical circuits hook up a linear series of all regions related to a specific function (e.g info from eyes goes to regions for detecting colour & brightness then goes to regions for shape then to movement etc.)
- Related brain structures are not always linearly linked & some expected connections are missing as unconnected regions have widely different functions
- Therefore, parallel pathways are more selective than connections in a purely serial circuit but our conscious experiences remain unified
66
What is the 7th principle of the NS function?
7) Sensory & motor divisions permeate the NS
- The Bell & Magendie law exists (segregation of SNS & motor functions)
- The lower brainstem regions (hindbrain & midbrain) are extensions of the spinal cord--> retain the division
- Orienting the body to stimuli is an important midbrain function (receives sensory input for Colliculi & motor output from tegmentum)
- The sensory nuclei in the thalamus are not segregated because they are in lower structures--> control movements
- Aside from thalamic nuclei, other nuclei have neither sensory nor motor functions but perform more integrative tasks
- Layers 1, 2, 3 of the cortex integrate sensorimotor operations, layer 4 always sensory inputs, layer 5 & 6 always motor outputs
67
What is the 8th principle of the NS function?
8) The brain divides sensory input for object recognition & movement
- Evolution of the sensory system first occurred for influencing movement, not for recognizing things
-Visual info in the cortical circuit--> from eyes to thalamus--> to the visual region of occipital lobe--> info diverges along 2 separate pathways--->
- the ventral steam (leads to temporal lobe) for object identification
- the dorsal stream (leads to parietal lobe) for guiding movements relative to objects
People with ventral stream injuries (blind for object recognition) while people with dorsal stream injuries (clumsy reaching movements)
- Unconcious movement system--> always acts in the present in response to ongoing sensory input
- Conscious object recognitions system--> allows us to escape the present & bring info from the past
68
What is the 9th principle of the NS function?
9) Brain functions are localized & distributed
- Broca--> damage to frontal lobes--> unable to produce spoken language
- Wernicke--> damage to temporal gyrus-->deficits in language comprehension
- It is only when the majority of neurons in a region are destroyed that we see catastrophic functional failure
- Widespread but diffuse damage may leave functional abilities intact but damage to a fairly localized region is irreversible
69
What is the 10th principle of the NS function?
10) NS works by juxtaposing Excitation & Inhibition
- In producing movement, the brain uses excitation (increased neural activity) to produce action & inhibition (decreased neural activity) to prevent other actions
- A brain injury could lead to change in the balance between excitation and inhibition
- Tourette & Parkinson--> basal ganglia dysfunction--> lack of voluntary movement coordination--> inappropriate language & hand tremors
- These people cannot generate excitation needed to produce deliberate movements
