Unit 4 - Central Nervous System Flashcards
- large scale dissection of different brain regions
- usually visible with the naked eye
- examples include the spinal chord, brainstem, and cortex
these are all characteristics of which organizational region for the CNS:
macroscale
- related to individual neurons and to large networks of neurons
- ex: the cortex can be dissected into different function regions for things like vision or attention
these are characteristics of which organizational region for the CNS:
mesoscale
- require a microscope
- ex: dendritic spines and axons that communicate
these are characteristics of which organizational region for the CNS:
microscale
- require a high-power microscope, or other mathods that enable analysis at the molecular level
- ex: synapses and vesicles, sub-cellular organelles
these are characteristics of which organizational region for the CNS:
nanoscale
define sagittal
from the side
define coronal
from the front or back
define horizontal
view from the ‘top’ (bird’s eye view)
dorsal is _______, ventral is _______
up, down
in the spinal chord, ventral is _______, and dorsal is _______
toward the body, toward the back/periphery
the space between cortical folds
sulcus
the actual folds of the brain where cells are contained
gyrus
true or false: sulci are functional parts of the brain
false, they are landmarks
what is white matter?
axon tracts containing myelin and glial cells
what is grey matter?
the cells of the brain
what is the brain ventricle?
areas containing cerebrospinal fluid
in what direction do signals travel on the spinothalamic pathway?
from spinal cord to the thalamus
in what direction do signals travel on the thalamocortical pathway?
from the thalamus to the cortex
which structure of the brain is the one to have most recently evolved?
the cortex
true or false: many rules of the how the CNS is organized are preserved across species
true
what are the six major divisions of the macroscale in the CNS?
1) cerebrum
2) diencephalon
3) brainstem
4) cerebellum
5) spinal cord
6) retina
this division of the macroscale CNS responsible for thought, language, and memory
cerebrum
the division of the macroscale CNS responsible for sensory relay to the cerebral cortex, hunger, thirst, and aggresion
diencephalon
the division of the macroscale CNS responsible for arousal, movement, breathing, swallowing, etc.
brainstem
the division of the macroscale CNS responsible for coordination, balance, and motor memory
cerebellum
what are the three layers of the meninges?
the dura matter, arachnoid matter, and pia matter
- outermost layer
- thick and durable
- elastic
- supports blood vessels
these are characteristics of which layer of the meninges?
dura matter
- cushioning layer
- does not follow the cortex into the sulci
these are characteristics of which layer of the meninges?
arachnoid matter
- thin delicate layer
- completely encloses the brain and spinal cords
- permeable to fluids
- densely covered in blood vascularization
these are characteristics of which layer of the meninges?
pia matter
the pia matter of the meninges is permeable to _____
fluids
what is meningitis?
inflammation of the meninges. messes with blood flow to the brain
the dorsal root of the spinal cord carries ________ information from the periphery and the ventral root carries ________ information to act on muscles
sensory, motor
what is the brain stem comprised of?
the midbrain, pons, and medulla
what is the main function of the brainstem?
connects regions of the cerebrum with the spinal cord
what is the function of the midbrain?
contains dopaminergic cells that are involved in motor control
what is the function of the pons?
serves in respiration
what is the function of the medulla?
serves in cardiac control, respiration control, and other vital functions
there are about as many neurons in the cerebellum as there are in the:
forebrain
this structure of the brain is important for balance, motor learning, and posture contral. many other functions such as social behaviours have also been attributed to it.
cerebellum
what are the two main structures of the diencephalon?
the thalamus and hypothalamus
what is the function of the thalamus?
involved in receiving inputs from the external world
what is the function of the hypothalamus?
involved in endocrine control, sleep, stress, almost everything
damage to the cerebellum may disrupt:
posture and gait
damage to the diencephalon may disrupt:
endocrine signalling and lead to changes in energy balance, sleep, stress, etc.
what is the function of the cortex?
different regions are responsible for different aspects of sensory/motor function
damage to the specific parts of the cortex may:
cause very specific changes in the funtion of these regions
which part of the brain does Alzheimer’s affect?
the cerebrum/cortex
what is topography?
the spatial distribution of parts within an organ
neurons in the brain are located topographically, which means:
neurons are most connected to other neurons located close by
neighbouring brain regions often have complimentary function, which means the brain is:
topographically organized
how are the mesoscale and macroscale measured?
fMRI, which uses blood oxygen level signals to infer neural activity
how are the mesoscale and mircroscale measured?
confocal fluorescense microscopy, which can study signle neurons and their parts, even measuring activity in real time
how are the microscale and nanoscale measured?
electron microscipy, which can study vesicles and synapses
- contains many nuclei, often with different functions
- body temperature
- arousal
- circadian rhythms
- reproduction behaviours
these are all characteristics of:
the hypothalamus
what % of inputs to the lateral geniculate nucleus (LGN) come from the retina?
10%
different parts of the thalamus connect _______ to the parts of the cortex
selectively
the lateral geniculate connects to the:
visual cortex
the medial geniculate connects to the:
auditory cortex
true or false: the thalamus only communicates with sensory cortex
false, some thalamic regions communicate with the “cognitive” regions of the brain
what is the thalamic reticular nucleus (TRN)?
a region of the thalamus which contains a nucleus with entirely inhibitory cells
what is the function of the TRN?
inhibits the activity of the primary and secondary thalamic regions
how many cortical layers are in the thalamus?
six
neurons within a cortical column as a ‘unit’ to respond to:
similar sensory features
what are the four coritcal lobes?
- frontal lobe
- parietal
- occipital
- temporal
which lobe is responsible for working memory, planning, action generation/inhibition?
frontal lobe
which lobe is responsible for somatosensory activation, and sensorimotor integration?
parietal lobe
which lobe is responsible for visual cortex and all visual subregions?
occipital lobe
which lobe is responsible for regulating the auditory cortex, and other ‘association’ cortex regions?
temporal lobe
what is the associational cortex?
a multimodal processing center, where motor and sensory information are integrated
the map of how much brain area is devoted to sensing each part of the body
the homunculus representation
the motor cortex and the somatosensory cortex are separated by the:
central gyrus
stimulation of different regions can evoke different motor outputs from different parts of the body on the:
contralateral side of the body
what were the Penfield experiments?
awake patients undergoing epilepsy surgery received cortical stimulation
most neural pathways are __________ and cross over to the opposite side of the brain or spinal cord
bilaterally symmetrical
what are commissures?
crossing axons
describes to the projection from the visual cortex to inferior temporal cortex. concerned with determining what an object is and where it is located in visual space
ventral visual stream
describes the projection from the visual cortex to posterior parietal cortex. concerned with determining where an object is located and motion of objects
the dorsal visual stream
neurons in the inferotemporal cortex are sometimes tuned to:
particuar faces
what is the fusiform face area (FFA)?
identification of person
what is the occipital face area (OFA)?
perception of specific facial features
the FFA and OFA connect to regions of the brain that link:
faces to emotions, memory, social information, and speech processing
what are mirror neurons?
cells that increase activity during both the execution and observation of an action
where are mirror neurons located?
the premotor cortex
widespread projections from association neocortex converge on the:
hippocampal region
in the case study of HM, the surgical removal of the hippocampus resulted in:
severe antegrade amnesia
HM helped us discover that:
brain structures underlying explicit and implicit memory are different
how many neurons are in the human brain?
~80 billion
the proportion of neurons to glial cells is:
brain region specific
in the hippocampus, 80% of neurons are ________ and 20% are ________
excitatory pyramidal cells, inhibitory neurons
inhibitory cells release ______, and excitatory cells release ______
GABA, glutamate
- mainly on excitatory neurons
- inputs drives excitation
spines
highly ramified structures extending up to 0.5mm from the cell body. spines are found here.
dendrites
inputs are integrated here, and if the input is strong enough an action potential will be initiated
cell body
action potentials travel down this structure and when the pre-synaptic terminal is reached, the process of neurotransmitter release is initiated
axon
what is an EPSP?
excitatory post-synaptic potential, facilitates the generation of an action potential
what is an IPSP?
inhibitory post-synaptic potential, can prevent action potentials
what is feedforward excitation?
one neuron fires an action potential and activates the next neuron
what is feedforward inhibition?
activation of interneurons by excitatory inputs. when excitation arrives from one one region, inhibitory and excitatory cells in the next region will be activated
what is feedback excitation/inhibition?
feedback locally within a region will stop the activity of local neurons
what is lateral inhibition?
when the neuron in one region fires an action potential, it activates an inhibitory cell, which prevents other neurons within that region from being active. this way the signal can be propogated to specific regions.
lateral inhibition is important for coding:
sensory information
in the hippocampus, the excitatory cells are densely pasked in the:
dendate gyrus and pyramidal cell layers
- required for learning new declaritive memories
- critical for spatial learning and memory
- also important for non spatial learning
- critical for making associations between events occuring in close temporal succession to each other
hippocampus
what is a place cell?
one that forms a ‘place field’ which is an area of the environment that is encoded by the cell
most pyramidal cells exhibit ________ characteristics, and most ________ are pyramidal cells
place cells (x2)
true or false: one place cell can encode for multiple environments
true
hippocampal cells get inputs from ______ with different spatial layouts and summate to generate a place cell in the hippocampus
grid cells
both excitation and inhibition are likely involved in generating:
place field firing in hippocampal regions
what is synaptic plasticity?
the capacity to alter the physiological strength of transmission by modifying past activity and behavioural experience
underlies numerous important processes, including short and long-term memory, learning, brain development, and remodeling of brain circuits after injury
synaptic plasticity
changes in EPSP amplitude are a measure of:
synaptic plasticity
EPSP’s arise from activity at which receptors?
NMDA and AMPA
where are NMDA and AMPA receptors found in high density?
dendritic spines
what is long-term potentiation (LTP)?
a high frequency stimulation causes a long-lasting change in the response to subsequent stimulations
how long can LTP last for in an intact animal?
more than a year
what are the two main conditions for NMDARs to conduct ions
postsynaptic depolarization and glutamate binding
what are NMDARs?
voltage-dependent, chemically-gated channels. they are coincidence detectors
what is CaMKII?
calcium/calmodulin protein kinase II. is phosphorylates proteins like AMPARs
induction and expression of LTP require:
activation of NMDARs, protein kinases, phosphorylation of existing proteins, and insertion of AMPARs
what does adding more postsynaptic receptors do?
increases synaptic strength
NMDA receptors are unblocked by:
depolarization and calcium entering the cell
when more AMPA receptors are inserted after calcium influx occurs, _______ is expressed
LTP
dendritic spines are always:
changing
how can spatial memory be tested in mice?
the Morris Water maze, where mice have to learn to find a hidden platform in cloudy water. however, blocking NMDA receptors during training impairs performance of this task
