Exam 1 Flashcards
1
Q
historical perspective
A
- ancient egypt: preserved liver, lung and heart, the brain was seen as irrelevant
- juedo-christian: lots of discussion about heart and mind, but the brain in terms of psychological processess
- buddhism: science of the mind, relationship between the observer and the observed
2
Q
philosophy: da vinci
A
- first thinker to put the brain at the center of his thoughts
- drew the brain
3
Q
philosophy: descartes
A
- “i think therefore i am”
- cartesian dualism: the mind is only partially an emergent property of the brain
- the mind at its core is independent of the brain
- brain is involved in “reflexes”
- free will and moral choice are not part of the machine brain
- humans have a nonmaterial soul (mind) as well as a material boy
- believed that the pineal glad was the point of contact btw the 2 bc its in the middle of the brain and there is only 1 (wrong)
4
Q
philosophy: kant
A
- noumenal: world that exists when you’re not looking at it, the world as it is
- phenomenal: the world we perceive through our senses - quite diff from reality
5
Q
phrenology
A
- pseudoscience for the study of head size and head shape to understand psychological processes and differences
- localization of function
6
Q
initial studies of localization of function
A
- diff brain regions specialize in specific functions and types of processing
- evidence that damage to specific brain regions causes predictable impairments (neuropsychology)
- Paul Broca: damage through stroke to small brain area lost ability to speak
- studying the amount glucose in a particular area of the brain to see how active or de-active it is while: hearing, seeing, reading or speaking
7
Q
21st century perspective on LOF
A
- known that many areas of the bran come together to generate language and process
- many different functions may depend on the same brain areas
- one function may rely on many different brain areas
8
Q
LOF: insula example
A
- has a viscerotropic map of your organs
- critical for the feeling states of your body
- like gut or butterfly feelings in stomach: actually happen in the brain but its being mapped in the gut
- created for things like physical and psychological pain
9
Q
plasticity
A
- ability to develop and change through production of neurons, axon terminals etc
- brain is fundamentally plastic and maliable
- can be good or bad depending on nature of behavior
- genomic plasticity: can’t change the base pairs of DNA, but some influence over the expression of genes can occur
10
Q
def of neuroscience
A
- scientific study of the nervous system with goal of understand the biology underlying behavior and experience
- examine the ways in which the structures and actions of the brain and body produce mind and behavior
- ways in which behavior and environment modify the structures and actions of the brain
11
Q
spatial resolution
A
- precision with which where neuron activity occurs in the brain
- mirco meters up to entirety of the brain
- fMRI has reasonable spatial resolution but not great bc in a few millimeters there are millions of neurons doing different things
- patch-clap recording: high resolution but very invasive usually only on animals
12
Q
temporal resolution
A
- to what precision can we measure the timing to what neuronal signal we care about
- fMRI: temporal resolution of 2 sec, but neurons fire 4-500 times per second, missing lots of info
13
Q
strokes: Broca’s patient Tan
A
- Tan had a stroke in the interior portion of the left lobe, could only say Tan
- lesion in the area of the brain known for generating language
- breakthrough in understanding LOF
14
Q
phineas gage: traumatic brain injury
A
- had iron rod go through his brain
- survived but his personality changed: became impulsive and mean
15
Q
SM: Urbach-Wiethe Disease
A
- hypercalcification of cells in the brain
- had no amygdala on either side
- didn’t feel pain or fear: lost ability to generate emotions and rational behaviors
- could cognitivley model it, but didn’t have visceral sensations of these feelings
16
Q
HM: surgery
A
- had severe seizures, removed hippocampus and surrounding regions, first of this type of procedure
- HM lost the ability to form new memories but could still learn procedural tasks
- shows that memory is multiple areas in the brain
17
Q
frontotemproal dementia
A
- progressive deterioration from the prefrontal cortex backwards
- first symptom: happiness, humor
- progresses to deficit in exec control, rationality etc
18
Q
cellular structure of neural tissue: golgi stains
A
- fill the whole cell, including details but only stain a small portion of neurons
- a first look into the cellular structure
- using chemical solution
19
Q
cellular structure of neural tissue: ramon y cajal
A
- used golgi staining to better understand neurons and the idea of neural circuits
- neuron doctrine: neurons are distinct entities and info travels one way from dendrite to axon
20
Q
microscopy
A
- optical microscope
- electron microscope: way deeper
- serial electron microscopy: high spatial resolution
21
Q
calcium imaging
A
measures the activity of a neuron by measuring changes in calcium levels of that neuron
21
Q
connectomics
A
examination of connectivity pathways in the brain
22
Q
neuropixels
A
- record neuronal activity in living brain tissue with very high spatial and temporal resolution: very invasive (often done w rats)
- now neuro pixel probes for humans also exist
23
Q
scalp recorded electroencephalography (EEG)
A
- measures electrical activity of neurons non-invasively through electrodes placed on the scalp
- noninvasive
- EEG has strong temporal resolution but poor spatial resolution
- index levels of:
- arousal and attention
- emotion, motivation, depression
- sleep states
pros: strong temporal resolution, noninvasive and cheap, mobile
cons: poor spatial resolution, indexes post-synaptic potential of pyramidal neurons in the outer cortex
24
structural magnetic resonance imaging (MRI)
- generates 'static' high resolution images of tissue
- picks up distribution of hydrogen protons
- different tissue types have different hydrogen densities
25
MRIs and schizophrenia
- studies show the brain before developing and 10 years after developing schizophrenia
- shows reduced amount of matter in the brain after developing
- enlargened ventricle filled with spinal fluid
- high dimensional brain mapping of thalamic deterioration in schizophrenia
26
diffusion imaging
- white matter structure of the brain: axons are covered in myelin which is white
- use color to understand the orientation of the direction of axial projection
- generates images by assessing the mobility of hydrogen protons along white matter tract
limitations: static images only
27
functional magnetic resonance imaging (fMRI)
- creates moving images
- when nerve cells are active they increase the consumption of energy which results in increased blood flow
- brain doesn't store energy which allows us to use fMRI to see what nerve cells are active
- indexes blood flow (hemoglobin)
- sensitive to hemoglobin
- BOLD (blood oxygenation dependent level)
- commonly used metric for summarizing fMRI activity
- level of oxygenation that is dependent on what the person is doing at that point in time
28
spatial and temporal resolution of fMRI
- dependent on the cerebrovascular system
- spatial resolution fMRI is about 2mm (pretty good but not great)
- relatively weak temporal resolution, takes about 10 sec, although certain paradigms allow for about 2 to 4 sec temporal res
29
fMRI examples
- depression is characterized by reduced neural responses to reward cues
- can be used to see if those at risk with 1 mental health issue have diff neural responses to those at risk with a diff issue
30
fMRI pros and cons
pros:
- good spatial res
- allows you to make inferences about brain activity within the brain (unlike EKG)
cons:
- poor temp res
- for the most part, it is limited measuring
31
positron emission tomography (PET)
- inject radioactive isotope (tracer) that binds to specific molecules of interest
- unstable number of neutrons
- PET detects gamma rays as these isotpoes break down
32
PET pros and cons
pros:
- assesses the concentration of many types of molecules (ex. neurotransmitters, receptors)
cons:
- like fMRI has poor temporal res and has worse spatial res than fMRI
33
neurons
- foundation for communication with the nervous system
- foundation of most simple and complex of all behavior
- approx 100 billion nuerons and trillion synapses in human brain
- varied in size and form
34
neuron doctrine
- neurons are distinct entities (individual cells)
- info travels in one direction from dendrite to axon
- info is transmitted from cell to cell across tiny gaps called synapses
- communication within a neuron is electrical via action potentials
- communication btw neurons are chemical via NT
35
neuroanatomy: input zone
- receives info from other cells through dendrites
- dendritic spine: small protrusion from dendrite that receives input from single axon at synapses, post synaptic portion of the synapse
36
neuroanatomy: integration zone
- cell body (soma) region where inputs are combined and transformed
- final integration at the axon hillock (where cell body ends and axon begins and action potential begins)
- integrates input into all-or-none electrical signlas that travel down axon and innervate target cells
37
neuroanatomy: conduction zone
- single axon (or nerve fiber) conducts output information away from the cell body as an electrical impulse
38
neuroanatomy: output zone
- axon terminals at the end of the axon communicate activity to other cells (neurons or target muscles or glands)
39
types of neurons
- multipolar: most common
- bipolar: common in sensory systems, vision
- unipolar: common in touch sensation
40
presynaptic vs postsynaptic neurons
- pre = sending
- post = receiving
- only in reaction to 2 neurons, not inherently 1 or the other
41
synapse
- communication within a neuron along the axon is electrical
- communication btw neurons is chemical via neurotransmitters
- cellular location where info transmitted from one neuron to another via neurotransmission
42
synapse membranes
- the presynaptic membrane on axon terminal of the presynaptic neuron
- a postsynaptic membrane on the dendrite or cell body of the postsynaptic neuron
- synaptic cleft: a gap that separates the membranes
43
synaptic vesicles
- small spheres in presynaptic axon terminals that contain neurotransmitters
44
depolarize vs hyperpolarize
neurotransmitters can either increase (depolarize) or decrease (hyperpolarize) the likelihood of the postsynaptic neuron firing
45
glial cells
- nonneuronal cells that provide structural, nutritional and other types of support to brain
- directly affect neuronal processes by providing neurons with raw materials and chemicals signals that later neuronal structure and excitability
46
types of glial cells: Astrocytes
- partner to neurons
- regulate blood flow to meet metabolic demands
47
types of glial cells: oligodendrocyte/schwan cell and axon myelination
- myelin sheath: fatty wrapping around axon
- in the periphery called Schwan cells
- not all neurons are myelinated because its a uge metabolic investment for the body to myelinate all of them
- produced by oligodendrocytes in CNS, Schwann cells in PNS
- facilitates speed and conduction of electrical impulses down axon: action potential
48
types of glial cells: oligodendrocyte/schwan - nodes of ranvier
- gaps in myelin sheath that further facilitate speed of action potential
49
types of glial cells: oligodendrocyte/schwan - diffusion imaging
- models the microstructural integrity of myelin sheath
50
types of glial cells: oligodendrocyte/schwan - multiple sclerosis
- deterioration of myelin in the nervous sytem
51
types of glial cells: microglial cells
- the brain's immune system
- microglial cells break down debris in the brain and target pathogens
- important following brain damages
- the 'trimming' of unused dendrites by microglial is central to learning and brain dev
52
neural tissue
- gray matter: contains more cell bodies and dendrites that lack myelin (prominent in cortex and subcortical nuclei)
- white matter: consists mostly of axons with white myelin sheaths (tracts)
53
neural tissue within the CNS
- nucleus: a collection of neurons
- cortex ('bark'): an outer surface that contains layers of neurons (ex. cerebral cortex, cerebrum), ~2-4mm thick
54
neural tissue within the PNS
- outside the CNS, in the periphery
- ganglia: a collection of neurons
- nerves: bundle of axons
55
central nervous system (CNS)
- consists of the brain and spinal cord
- encased by protective bones (skull and vertebrae)
56
peripheral nervous system (PNS)
- all other parts of the nervous system, found outside the skull and spinal column (ie neurons and nerve processes outside CNS)
- somatic nervous system: nerves that interconnect the brain and major muscles and sensory systems of body
- autonomic nervous system: nerves that connect to viscera (internal organs)
57
peripheral nervous system: autonomic system
- brain's main system for controlling/regulating the organs of the body
- two subdivisions
- sympathetic nervous system: 'fight' or 'flight' (arousing), prepares the body for action, immune system
- parasympathetic nervous system: 'rest and digest' (calming), helps body to relax, recuperate and prepare for future action
- often in opposition: heart rate is slowed by parasympathetic activity, increased by sympathetic
58
pre vs post ganglionic neurons
- both sympathetic and parasympathic preganglionic neurons release acetylcholine
- which faciliates sympathetic and parasympathic reactions
- pre: going from brain to body
- post: receiving info from the brain and synapsing onto the organs ?
59
postganglionic neurotransmitters
- differential effects of sympa vs parasympa systems mediated by different postganglionic neurotransmitter
- sympathetic postganglionic neurons use norepinephrine which tends to accelerate activity
- parasympathetic postganglionic neurons use acetylcholine which tends to slow down activity
60
CNS placement vocab
- medial: towards the midline (center)
- lateral: to the side (left or right)
- ipsilateral: on the same side
- contralateral: on the opposite side
- Dorsal: on top
- Ventral: bottom
- Lateral: sides
- Medial: middle
61
CNS: 3 customary orientations for viewing the brain and body
- coronal plane: divides the brain into front (anterior) and back (posterior)
- axial plane: divides the brain into an upper and lower part
- sagittal plane: bisects the brain into right and left halves
62
CNS: cerebral cortex
- outermost layer of the cerebral hemispheres
- convoluted brain surface (cerebral cortext) has two types of areas
- A gyrus (pl. gyri) is a ridged or raised portion or "peak"
- A sulcus (pl. sulci) is a furrow or "valley"
- frontal lobe: plan and perform motor actions, cognition, exec processing, working mem, emotion reg
- parietal lobe: somatic (body) sensation, spatial-motor processing, attention, higher-order cognition, many other functions
- temporal lobe: audition, higher visual processing, memory
- occipital lobe: visual processing
63
CNS: subcortical structure
- basal ganglia
- limbic system
64
CNS: cerebellum
- sensory motor integration
- crucial for motor coordination and control
- important in some cognitive functions, especially certain forms of learning
- Purkinje cells are central to cerebellar function
65
ventricle system
- series of chambers filled with cerebrospinal fluid (CSF) which functions as a shock absorber and exchange medium btw blood and brain macroenvironment
66
blood supply system
- stroke caused by rupture (hemorrhage) or blockage of blood vessels, leading to insufficient blood supply
- the blood-brain barrier is the result of higher resistance in brain capillaries that restricts the passage of large molecules
67
neurophysiology def
- study of the life processes of a neuron, which use electrical and chemical signals to communicate
- information flows within a neuron via electrical signals, and btw neurons through chemical signals
68
neurophysiology: resting membrane potential (short version)
- resting membrane potential is the relatively static membrane potential of neurons at rest
- involves building up a negative voltage in the cell to prepare it to fire (ex. have an action potential)
- slingshot analogy: pulling the band back to create the energy that will launch the thing in space
69
neurophysiology: action potential (short version)
- rapid all-or-none electrical signal that travels along the axon of a neuron, this is when the neuron "fires"
- firing the sling shot or jumping off the board
70
neurophysiology: neurotransmitter role
- chemical messenger btw neurons that bind to receptors on the post-synaptic membrane
- generates local and graded potential that either move the neuron closer or father away from firing
- proximal to where the neurotransmitter binds to the synapse
71
electrophysiology vocab: ions
- all living cells possess an electrical charge: they are more negative on the inside
- long ago, nerve cells exploited this electrical property to transmit info
- ions: electrically charged molecules
- anions are negatively charged (gained electrons)
- cations are positively charged (lost electrons)
- potassium
- calcium: critical for that final push at the axon terminal that moves the synaptic vessels towards the wall of the membrane
- chloride ions are important for inhibitory, decrease the likelihood that a neuron will fire
72
electrophysiology vocab: distribution of ions across the membrane
- ions are dissolved in the intracellular fluid (or cytoplasm) and the extracellular fluid which are separated by the cell membrane
- a neuron is polarized at rest, with a difference in electrical charge
73
electrophysiology: resting membrane potential ions- (expanded)
- Na: sodium ions
- very few sodium ions inside a cell compared to outside because of the sodium-potassium pump
- drive the action potential, fire the slingshot
- K: potassium ions
- potassium ions drive the resting membrane potential, pull the slingshot back
- anchored by negatively charged proteins in the cell
- K equilibrium level is the resting membrane potential
- Cl: chloride ions
- Ca: calcium ions
74
electrophysiology: ion channels and pumps overview
- ions cannot freely pass through the cell membrane but must be transported across the cell membrane via ion channels or pumps
- ion channels are tubelike pores in the cell membrane that allow ions of a specific type to pass through the membrane
- channel: doorway
- pump: active transport system
75
electrophysiology: ion channels and pumps - constitutively open ion channels
- stay open all the time
- these 'open' channels have selective permeability to certain ions
- 'open' potassium ion (K) channels are central to resting potential
76
electrophysiology: ion channels and pumps - gated ion channels
- open and close in response to certain signals (chemical ligands, voltage changes)
- gated sodium in (Na) channels are central to action potential
- ligand-gated: open when molecule (neurotransmitter) binds to a receptor, drivers of postsynaptic potential EPSP or IPSP
- voltage-gated: open when the cell membrane reaches a certain voltage, propagate the electrical charge down the axon
77
electrophysiology: ion channels and pumps - sodium-potassium pump
- central to neural signaling
- pump 3 sodium ions out of the cell for every 2 potassium ions pumped into the cell
- sets the stage for negative voltage in cell
- preparing for action potential
78
electrophysiology: 2 ionic forces that establish resting potential
- diffusion: particles move from areas of high concentration to areas of low con, that is they moved down in their concentration gradient
- electrostatic pressure: ions flow towards oppositely charged areas, along a voltage gradient
- like charges repel and opposite charges attract
79
electrophysiology: resting potential
- goal: to prepare to trigger the action potential
- large negatively charged proteins sets the stage for a negative voltage in the cell
- as K ions build up inside the cell they also diffuse out through K ion channels, down their concentration gradient
- as neg charge builds up inside cell, it exerts electrostatic pressure to pull K ions back in through K ion channels
- eventually opposing forces exerted by the K concentration gradient and electrostatic pressure reach an equilibrium potential at about -60mv
- equilibrium potential of K is the same as resting membrane potential - K is not flowing in and out that much, pressures are balanced
- K is the 'hero' of the resting membrane potential
- recall that RMP is the state of the neuron when its no firing and is at rest
80
triggering the action potential
- presynaptic neurons from synaptic connections on dendrites and cell body of the postsynaptic neuron
- NT from the presynaptic neuron can either increase or decrease the likelihood of the postsynaptic neuron firing
- Neurotransmission that hyperpolarizes
the postsynaptic neuron decreases the
likelihood of the postsynaptic neuron
firing
- Neurotransmission that depolarizes the
postsynaptic neuron increases the
likelihood of the postsynaptic neuron
firing
81
triggering the action potential: hyperpolarization vs depolarization
- hyper: increase in membrane potential in the interior of the membrane becomes more neg and further from zero
- de: decrease in membrane potential in the interior of the cell becomes more positive and closer to zero
82
triggering the action potential: hyperpolarization vs depolarization stimuli effect
- up to a point, te application of depolarizing pulses to the membrane via influx of Na ions produces graded localized responses
- except when the membrane reaches threshold voltage (about ~40mV) then it triggers the action potential
- membrane potential rapidly reverses and the inside of the cell becomes positive
83
postsynaptic potentials
- when an action potential reaches the end of the axon it causes the releaseof NT from the presynaptic nueron into the synapse where they then bind to receptors on the postsynaptic neuron
- info moves across the synapse from the axon on the presynaptic neuron towards the target postsynaptic neuron
- brief changes in resting membrane potential of postsynpatic cell that occur in response to a neurotransmitter binding to receptors
- chloride ions
84
postsynaptic potentials: local and graded
- local: because voltage changes are at the synapse
- graded: because you need a lot of influx of sodium to be excitatory or inhibitory, towards or away
85
EPSP and IPSP
- excitatory postsynaptic potentials and inhibitory postsynaptic potentials: change in voltage at the synapse due to NT
- ESPS pushes cell towards action potential, lets in positively charged ions, depolarizing the cell through influx of sodium ions (positively charged)
- IPSP moves cell away from firing, hyperpolarization through influx of chloride ions (negatively charged)
86
summation/integration of EPSP and IPSP
- nature of NT released by presynaptic cell helps determine whether synapse excites or inhibits postsynaptic cell
- some transmitters generate EPSP and IPSP
- neurons perform info processing in axon hillock to summate or integrate to 1000s of EPSP and IPSP occuring at any moment
- postsynaptic potentials are local, graded and dissipate as they spread away from point of origin
87
spatial summation of EPSP and IPSP
- combination of graded potentials that come from diff parts of neuron
- packs bigger punch near axon hillock
- need many?
88
temporal summation EPSP and IPSP
- combination of graded potentials that arrive at axon hillock at diff times
- need to happen rapidly
89
action potential (expanded)
- brief but large changes in membrane potential that originate in the axon hillock and propagate along the axon
- after potentials are a temporary dip below resting membrane potential after action potentials
- all or none property of action potentials: the neuron fires at full amplitude or not at all
- the size (amplitude) is independent of stimulus size or strength
90
generation of the action potential
- resting membrane potential
- EPSP or IPSP
- thresholdof -40mv, voltage gated sodium channels open, causing rapid change of polarity the action potential
- sodium channels automatically close again, gated potassium channel open, repolarizing even hyperpolarizing cell (after potential)???
- all gated channels close, the cell returns to its resting potential
91
action potential: refractory phase
- upper limit to frequency of action potentials is ~1200 spikes per second
- only if there is so much EPSP it overwhelms the refractory phase
- with closely spaced stimuli only the first is able to trigger an action potential: the member briefly becomes refractory (unresponsive) to later stimuli
- absolute refractory phase: another action potential cannot be produced
- relative refractory phase: another action potential can only be produced by stronger stimulation than normal
92
propagation of action potential
- each adjacent region is depolarized and new action potential is triggered, propagating action potential down the axon
- action potentials travel in one direction toward the axon terminals
93
propagation of action potential: saltatory conduction
- in vertebrates, the axon potential travels inside the myelinated axon and 'jumps' from node to node, increasing speed for propagation
94
synaptic physiology: synapse parts
- mitochondria: power house of the cell, generates energy
- synaptic vesicle: store neurotransmitters, compartments that hold synaptic vesicles (storage granule)
- presynaptic membrane
95
synaptic physiology: sequence of synaptic transmission
- action potential is propagated over the presynaptic membrane
- when the voltage comes down it initiates propagation towards the presynaptic membrane
96
synaptic physiology: calcium ion channel
- as action potential propagates it changes the voltage of the presynaptic terminal leads to pening and influx of calcium ions, changing the voltage of the terminal and pushes the synaptic vesicles to the membrane and causes them to bump into it and merge with the wall and dump their contents into the synapse
- calcium ion influx into axon terminal facilitates synaptic transmission
97
synaptic physiology: receptor action - ionotropic receptors = ligands
- ligand-gated ion channels: open their ion channels when a neurotransmitter binds
- fast acting but transient effects
- ligands are molecules that fit into a receptor protein and activate or block it
- endogenous ligands: neurotransmitters or hormones made inside the body
- exogenous ligands: drugs and toxins from outside the body
98
synaptic physiology: receptor action - metabotropic receptors
- G protein-couples receptors, activate G proteins that trigger signaling cascades when a ligand binds
99
synaptic physiology: receptor action - agonist and antagonist
- agonist: exogenous molecule (drug) that fits into a receptor and acts like a neurotransmitter - like LSD
- antagonist: exogenous molecule (drug) that fits into a receptor and blocks the action of a NT - narcan
100
synaptic physiology: nature of postsynaptic receptors
- determines the action of a transmitter
- a particular type of NT can be inhibitory or excitatory at different synapses
101
synaptic physiology: receptors are malleable
- each subtype of receptor as unique distribution in the brain
- same transmitter may bind to a variety of receptor subtypes, triggering different responses
- receptor up-regulation: increase in receptor number
- receptor down-regulation: decrease in receptors
