Exam 1 Flashcards
a major goal of cognitive neuroscience is to define the relationships between ___
brain structure, brain function, and “consciousness”
brain structure pertains to:
distinct units (how they’re connected)
brain function pertains to:
how the units of the brain operate in real time
consciousness refers to:
an emergent property of brain function
what does EEG stand for?
electroencephalography
electroencephalography (EEG) provides excellent ____ resolution, but poor ____ resolution
temporal ; spatial (when but not exactly where)
millisecond time resolution is characteristic of which noninvasive method?
electroencephalography (EEG)
what does fMRI stand for?
functional magnetic resonance imaging
fMRI provides excellent ____ resolution, but poor ____ resolution
spatial ; poor (where, but not exactly when)
cognitive neuroscience was born from the combination of three related fields of research on the brain and behavior:
cognitive psychology, neurology, and neurophysiology/neuroimaging
how the brain works in healthy folks
cognitive psychology
cognitive psychology data was explicitly ____ based
behavior (avoids brain)
how brain damage affects behavior in clinical patients
neurology
neurology data was ____ based
deficit (behavior-brain linked)
how healthy brains work in animal models, later including humans with the development of noninvasive brain recording methods
neurophysiology/neuroimaging
true or false: despite lots of investigation, there is little agreement about what consciousness is, and how it might be studied
true
over the last ~2 million years, the human cortex has nearly ____ in size
tripled
cortex = ____
cerebral cortex
the cortex consists of mostly ____ tissue
homogeneous
the cortex is greatly ____ in primates and is critical to (but not sufficient for) “____” cognition
expanded ; “higher-order”
“subcortex” refers to
everything else in the brain
cerebellum, thalamus, basal ganglia, amygdala, hippocampus, midbrain, brainstem, etc
subcortex
the subcortex is ____ in size and internal structure
variable
the subcortex is similar in ____ and ____ with other mammals
structure and function
the subcortex is also essential to ____
higher order cognition
what are the three main components of the cortical surface?
gyrus, sulcus, and fissure
rounded protrusion of surface cortex (“mountain”)
gyrus
depression in surface cortex (“valley”)
sulcus
a particularly deep sulcus
fissure
____ of cortical surface is hidden in sulci and fissures (sulci within sulci)
2/3
cortical folding refers to cortical “____”
cortical “packaging”
cortical folding allows _____, and (maybe) speeds cortical processing time by keeping all brain regions relatively close together
lots of tissue in a small space
4 cortical lobes:
- frontal lobe
- parietal lobe
- temporal lobe
- occipital lobe
the boundary region between cortical and subcortical structures located between the frontal lobe and temporal lobe
insula
the ____ is where the first stage of cortical processing occurs
the “primary sensory” cortex
V1 =
primary visual cortex
V2 =
primary auditory cortex
S1 =
sensory
M1 =
motor
this view states that the thalamus relays sensory and motor signals up to the cortical processing areas, and downstream to the brainstem (except smell)
classic view
recent work has identified that the structure of the thalamus is mostly (~80%) connections from one region of the cortex to another region of the cortex
modern view
the thalamus is heavily involved in _____ connections
cortico-cortical
rather than primarily carrying sensory input to cortex, and motor signals out to the body (“first order” connections”), the thalamus is instead heavily involved in cortico-cortical connections, which are referred to as ____
“higher order” connections
firing modes appear to enhance (____) or inhibit (____) the ‘quality of a connection between brain regions
burst ; tonic
the firing mode is changed by relatively long periods of ____ or ____ input from brain stem and cortex
excitatory ; inhibitory
two divisions of the nervous system
peripheral and central
the autonomic nervous system is part of the ____ nervous system
peripheral
two components of the autonomic nervous system
sympathetic and parasympathetic nervous systems
the ____ nervous system controls self-regulated action of internal organs and glands
autonomic
the ____ nervous system controls AROUSING for non-digestive organ systems
sympathetic
the ____ nervous system controls CALMING for non-digestive organ systems
parasympathetic
the ___ is mostly concerned with housekeeping of the body, but can show strong effects of mental state, such as anticipation or threat reactivity
autonomic nervous system
the ___ branch tends to prepare the body for intense action ; ‘fight or flight’
sympathetic branch
the ____ branch tends to maintain homeostasis and repair ; ‘rest and digest’
parasympathetic branch
our brains make up ____% of our body weight, but consume ____% of our metabolic resources
2% ; 20%
functional imaging is dependent on ____ to track brain activity
blood flow
____ were historically considered “support” cells for neurons
glial cells
we think that there is approximately ____ glial cell for each neuron in the brain
one
excitatory and inhibitory from other neurons
neuronal input
neuronal summation occurs at the ____
axon hillock
how does neuronal output travel
down the axon to synapse with next neuron
the ____ neuron releases neurotransmitter (NT) into the synapse, which modulates activity of the ____ neuron, depending on the neurotransmitter and the receptor type
presynaptic ; postsynaptic
basal forebrain constellation of cholinergic neurons, including basal nucleus of meynert ; dorsolateral pontine tegmental constellation of cholinergic neurons
acetylcholine
is acetylcholine more widespread or more limited?
widespread
is serotonin more widespread or more limited?
widespread
is dopamine more widespread or more limited?
more limited
the function of this neurotransmitter is to enable muscle action, learning, and memory
acetylcholine
with alzheimer’s disease, ACh-producing neurons ____
deteriorate
the function of this neurotransmitter is to influence movement, learning, attention, and emotion
dopamine
excess dopamine receptor activity is linked to ____
schizophrenia
starved of dopamine, the brain produces the tremors and decreased mobility of ____
parkinson’s disease
the function of this neurotransmitter is to affect mood, hunger, sleep, and arousal
serotonin
undersupply of serotonin is linked to ____
depression
____ and some other antidepressant drugs raise serotonin levels
prozac
the function of this neurotransmitter is to help control alertness and arousal
norepinephrine
undersupply of this neurotransmitter can depress mood
norepinephrine
___ is a major inhibitory neurotransmitter
GABA (gamma-aminobutyric acid)
undersupply of this neurotransmitter is linked to seizures, tremors, and insomnia
GABA
____ is a major excitatory neurotransmitter; involved in memory
glutamate
oversupply of this neurotransmitter can overstimulate the brain, producing migraines or seizures (which is why some people avoid MSG in food)
glutamate
“___” and “___” signals (from other neurons) flow through dendrites and cell body to the axon hillock where these signals are averaged together across the cell and over a short period of time (“___”)
“go” and “stop” ; “summation”)
if ‘go’ signals win, the action potential is the ____ response
all or none
neurons fire at a ____ intensity
fixed
continuous ‘go’ input can increase the firing rate to the limit of the refractory period, perhaps up to ____ times per second
1000
(EEG) records the electrical activity of the ____ in real time
cortex
____ brain activity is missing from EEG
non-cortical
pyramidal neurons in the cortex are oriented in ____
columns
as these neurons sum input from other neurons, their electrical charge becomes more _____ near the outside surface of the cortex
voltage-negative
real time or “____” EEG is useful for tracking long-lasting ‘____’ mental states, like alertness or sleep
“raw” ; ‘tonic’
repeated averaging enhances the small but consistent ‘hidden’ signal
event-related potential (ERP)
true or false: brains will respond pretty much the same on trial one as they do on trial one-thousand
true
true or false: different people’s brains respond differently
false; they respond similarly
averaging reveals the small, consistent EERP from the noisy EEG background, sort of like averaging the single pictures of a movie - the ____ elements remain
consistent
things that do not change appear ____, while things that do change ____ together
bolder ; blend
with ERP, ____ increases, and ____ decreases
signal ; noise
what does ERP stand for?
event-related potential
early ERP components (~100 ms after stimulus onset) are mostly driven by basic ____ features, like intensity
stimulus
early ERP components are sometimes called ____ components, because they are determined outside the body
exogenous
later ERP components (~250+ ms after stimulus onset) are mostly driven by _____ meaning of stimuli
psychological meaning
later ERP components are sometimes called the _____ components, because they are determined inside the body
endogeneous
the first ERP component related to a psychological process was the ____
P300
a big ERP shift ~300 ms after a ‘rare’ event
the P300
the P300 was (and is) a hot area of study because it revealed brain reactivity to all sorts of ‘psychological events,’ including ____ events
missing
the P3 is not a sensory response - the P3 can also reflect a ____
broken expectation
____ is not recognized in the P3 (it often falls into the background) whereas ____ is noticed immediately
consistently ; change
a major problem with ERP
source localization
because the brain is ____, not all parts of the brain are perpendicular to the scalp
folded
the ____ the activity is from the scalp, the ____ the signal (known as volume conduction)
farther ; weaker
as the signal travels, it spreads out, and loses strength (relationship between depth and strength)
volume conduction
true or false: strong EEEG voltage could represent weak activity close to the scalp OR strong activity from deeper in the brain
true
EEG/ERP source localization limitation: electrical activity ____ or _____ among folded sections of cortex
combines or cancels
EEG/ERP source localization limitation: source ____ is difficult to distinguish from source depth
strength
EEG/ERP source localization limitation: the exact ____ of sources is unknown
number
EEG/ERP source localization limitation: each person’s head _____ is slightly different
anatomy
what does MEG stand for?
magnetoencephalography
MEG looks for the ____ field that accompanies the voltage field
magnetic
MEG has the same ____ resolution as ERPs, but better ____ resolution than ERPs
temporal ; spatial
what does SQUIDS stand for?
superconducting quantum interference devices
do magnetic fields spread out like electric fields as they pass through the brain and skull?
no
without the smearing effect of volume conduction, MEG is only limited by the ____ and ____ of SQUIDS
size and number
MEG loses sensitivity sharply about ____ cm from the SQUID
5 cm
MEG is effectively blind to ___ brain structures
deep
MEG is really great for ____ cortical tissue, but has no sensitivity to deep cortical stuff
surface
what does fMRI stand for?
functional magnetic resonance imaging
fMRI yields colorful images that represent the ____ of brain activity with good precision, in a way that is easy to grasp
location
3 elements of MRI:
- strong, fixed magnet
- radio emitter and receiver
- weak, variable magnets
magnetic hydrogen protons (in water) align with the field, and spin at a known rate (128 MHz for a 3T scanner)
strong, fixed magnet
resonance radio wave energy at 128 MHz will “resonate with H protons and tilt them away from the main field
radio emitter and receiver
imaging smaller fields are added to across the area to be scanned, which allow a 2D image to be constructed
weak, variable magnets
this imaging method essentially detects the density of ____ in tissue, produces a stack of sharp images in about 15 minutes
structural MRI
this imaging method involves repeated, lower-resolution imaging of the brain, showing interest in image intensity as it CHANGES OVER TIME)
functional MRI (fMRI)
instead of focusing on water concentration, fMRI focuses on the small changes in signal intensity that accompany changes in local ____ oxygenation (BOLD contrast)
blood oxygenation
what does BOLD contrast stand for?
blood oxygen level dependent
high activity states trigger local increases in blood flow and volume (via astrocytes)
the “resupply” exceeds demand by about ____%
30%
this 30% excess of oxygenated blood ____ MRI signal intensity, because oxygenated blood contains slightly ____ iron than deoxygenated blood
increases ; less
how does iron affect magnetic fields?
it perturbs magnetic fields and causes signal intensity to sharply drop
because BOLD tracks the blood flow change, and not the neural activity that triggered it, BOLD signal onset is ____ and lasts for several seconds after scene offset
delayed
fMRI’s biggest weakness:
the typical fMRI sampling rate is far slower than the speed of the brain
true or false: consciousness is defined as correlated activity across at least 75% of the brain
false; there is little agreement about what consciousness is
true or false: consciousness is defined as the electrochemical activity of the brain oscillating above ~15 Hz
false; there is little agreement about what consciousness is
human skull volume has ____ over the last 2 million years
tripled
human skull volume has ____ over the last 5,000 years
a. remained stable
b. increased slightly
c. doubled
d. tripled
a. remained stable
human cortex shows unique structural features, such as:
a. homogeneous tissue organized in columns and layers
b. dense convolutions, including gyri and sulci
c. left-right symmetry in structure
d. all of the above
d. all of the above
true or false: the fissures of the cortex are unique to all individuals
false
true or false: subcortical structures operate independently from the cortex
false
true or false: the cerebral cortex contains primarily neurons, while subcortical structures are primarily glial cells
false
true or false: the autonomic nervous system is part of the central nervous system
false; part of the peripheral nervous system
true or false: psychological states can strongly influence the autonomic nervous system
true
what autonomic branch would be expected to be more active after eating a large meal?
parasympathetic
the thalamus may be critical to consciousness because of its:
a. broad structural connectivity with cortex and brainstem
b. high proportion of cortical - cortical connections
c. capability to switch between “burst” and “tonic” modes of transmission
d. all of the above
d. all of the above
a neuron is more likely to fire when:
a. excitatory input arrives on the cell body, vs. a dendrite
b. multiple excitatory inputs arrive simultaneously, vs. over time
c. excitatory input at the hillock follows multiple inhibitory inputs on the dendrites
d. all of the above
d. all of the above
neurons fire at a ____ intensity
fixed
a neuron is more likely to fire when:
a. excitatory input arrives on the cell body, vs. a dendrite
b. multiple excitatory inputs arrive simultaneously, vs. over time
c. inhibitory input at the hillock follows multiple inhibitory inputs on the dendrites
d. all of the above
b. multiple excitatory inputs arrive simultaneously, vs. over time
