Week 1 Lecture Flashcards
dorsal/superior
towards the top of the brain, or surface of the back
ventral/inferior
towards the bottom of the brain, or front of the chest
rostral
towards the nose (sounds like nostril)
caudal
towards the rear
bipeds spinal column
up/down
quadrupeds spinal column
horizontal
medial
towards the midline of the body
lateral
away from the midline
horizontal plane
up/down
sagittal plane
left/right
coronal plane
back/front; perpendicular to sagittal plane
midsagittal
directly down the center
parasagittal
parallel to sagittal plane
contralateral communication
most of our senses decussate to the contralateral hemisphere
ipsilateral communication
belonging or occurring on the same side of the body
sensory info coming in from one side of the body will be directed toward the ____ side of the brain
contralateral
what does the nervous system do?
coordinates actions and sensory information by transmitting signals to and from different parts of its body
what does the CNS consist of?
brain and spinal cord
what does the peripheral nervous system (PNS) consist of?
‘everything else’ = motor/sensory neurons that connect to CNS
what three sections does the brain consist of?
cerebrum forebrain, cerebellum, brainstem
what does the cerebrum consist of?
two cerebral hemispheres
what four sections does the cerebral cortex consist of?
frontal lobe, parietal lobe, temporal lobe, occipital lobe
what can gray matter be compared to?
the computer
what can white matter be compared to?
the wires in a computer sending information
what are the cerebral hemispheres connected by?
corpus callosum
fissures
very large sulci like the medial longitudinal fissure that divides the brain into two hemispheres
lissencephalic
lack of sulci and gyri
frontal lobe functio
executive function, emotion, personality, control of recent memory retrieval
parietal lobe
association areas, sensory integration, some language components
occipital lobe function
vision
temporal lobe function
hearing and memory
cerebellum function
motor control, balance, vestibular functions
brainstem function
involuntary systems
primary motor cortex function and location
movement; primary motor cortex
Broca’s area function and location
production of written and spoken language; frontal lobe
prefrontal cortex function and location
executive function; frontal lobe
primary sensory cortex function and location
tactile, sensory perception; parietal lobe
inferior portion of parietal lobe function
comprehension of language
primary auditory cortex function and location
hearing; temporal lobe
Wernicke’s area function and location
language comprehension, temporal lobe
hippocampus function and location
memory; temporal lobe
primary visual cortex function and location
vision; occipital lobe
limbic lobe function and location
drive related behaviors, emotional responses, movement, & memory; encircles the diencephalon
what are the first three brain subdivisions?
rhombencephalon (hindbrain), mesencephalon, prosencephalon (forebrain)
six stages of cellular processes needed for brain development
- neurogenesis
- cell migration
- differentiation
- synaptogenesis
- neuronal cell death
- synapse rearrangement
six stages of cellular processes needed for brain development
- neurogenesis
- cell migration
- differentiation
- synaptogenesis
- neuronal cell death
- synapse rearrangement
two phases of brain development characterized by the loss of structures
apoptosis and synapse rearrangement
what is the basic mechanism that directs each developing neuron to take on the appropriate structure and function?
differentiation; when cells reach their destinations, they express genes to make the proteins they need to acquire their specific appearance and function
- local environment (neighboring cells) influences differentiation
what is the significance of generating new neurons in adulthood?
neural plasticity
what is the process of synapse rearrangement?
- the nervous system refines its neural circuits by eliminating some synapses and strengthening others
- neural activity plays a central role: synapses that are frequently used are strengthened
- “neurons that fire together wire together”
- thinning continues in a caudal — rostral direction, so prefrontal cortex matures last
why is synaptic pruning adaptive?
inheriting extra trinucleotide repeats may cause mental impairment
which evidence shows that visual experience early in life is required to develop normal vision?
binocular deprivation results in a loss of dendritic spines and a reduction in synapses in the visual cortex; if deprivation lasts long enough, sight will never be restored
what does the prosencephalon develop into in the embryonic brain?
telencephalon (forebrain) and diencephalon
what does the rhombencephalon develop into in the embryonic brain
metencephalon and myelencephalon
what does the embryonic telencephalon develop into in the adult brain
cerebral cortex, basal ganglia, hippocampus, olfactory bulb, basal forebrain
what does the embryonic diencephalon develop into in the adult brain
dorsal thalamus, hypothalamus
what does the embryonic mesencephalon develop into in the adult brain
midbrain (superior and inferior colliculi)
what does the embryonic mesencephalon develop into in the adult brain
midbrain (superior and inferior colliculi)
what does the embryonic metencephalon develop into in the adult brain
cerebellum, pons
what does the embryonic myelencephalon develop into in the adult brai?
medulla
what does the ectoderm become
neural plate
what does the neural plate become
it folds to create the neural groove and ultimately closes to form the neural tube
neurulation
the formation of the neural tube
what does the neural tube develop into after neurulation?
spinal cord and brain
what are the primary vesicles?
prosencephalon, mesencephalon, rhombencephalon
what are the secondary vesicles?
telencephalon, diencephalon, metencephalon, myelencephalon
what does the neural tube form?
the central nervous system
what are the three subdivisions of the neural tube?
forebrain (prosencephalon, consisting of the telencephalon and diencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon)
neurogenesis
production of nerve cells
what is the process of neurogenesis?
- nonneural cells divide by mitosis and form the ventricular zone
- cells eventually leave the ventricular zone and become either neurons or glial cells
cell migration
massive movement of nerve cells
what is the process of cell migration?
- helps to establish distinct nerve cell populations (ex. layers of the cortex)
- neurons migrate from their birthplace in the ventricular zone to their final destinations in the developing brain, guided by radial glial cells and chemical signals
what do radial glial cells do?
they guide neurons from their birthplace in the ventricular zone to their final destinations in the developing brain
- span the width of the emerging cerebral hemispheres
differentiation
when cells reach their destinations, they express genes to make the proteins they need to acquire their specific appearance and function
- local environment (neighboring cells) influences differentiation
synaptogenesis process
- axonal growth cones (the tips of growing axons) navigate through the extracellular environment to reach their target cells
- filipodia emerge from growht cones at the tips of axons and dendrites
- axons are guided by chemicals released by the target cells
what chemicals are released by target cells during synaptogenesis?
chemoattractants and chemorepellents
what do chemoattractants do?
attract certain growth cones (eg. cell adhesion molecules)
what do chemorepellants do?
repel growth cones
apoptosis
selective elimination of excess neurons and synapses
how does apoptosis occur?
- death genes are only expressed when a cell undergoes apoptosis
- cells that make adequate synapses remain
- neurons compete for synaptic connections and neurotrophic factors
how do neurotrophic factors affect cell growth?
- cells compete for neurotrophic factors (proteins that give cells nutrients), and cells that don’t get these factors will die
what happens if apoptosis doesn’t happen?
brains get too big
what are two neurotrophic factors?
nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF)
nerve growth factor
produced by targets and taken up by the axons of innervating neurons, keeping them alive
brain-derived neurotrophic factor
similar to NGF
synapse rearrangement
the process by which the nervous system refines its neural circuits by eliminating some synapses and strengthening others
- neural activity plays a central role: synapses that are frequently used are strengthened
main feature of neural induction
production of cells that will become nervous tissue (gastrulation and neurulation)
main feature of proliferation phase
generation of neurons and glia through cell reproduction
main feature of migration phase
location of cells in appropriate brain areas
main feature of regional specification phase
differentiation of neurons into particular types with specific functions
main feature of myelination phase
ensheathing of neuron axons in fatty covering
main feature of synaptogenesis phase
formation of appropriate synaptic connections between neurons (communication)
main feature of apoptosis phase
elimination of mis-located cells and cells that failed to form proper synaptic connections
main feature of synaptic pruning phase
strengthening synapses in use, removing underused synapses
what direction does synaptic pruning occur in?
a caudal —> rostral direction, so prefrontal cortex matures last
fragile X syndrome
normal elimination of synapses after birth is blocked, resulting in mental impairment
- results from inheriting extra trinucleotide repeats in a particular gene on the X chromosome
binocular deprivation
no light to both eyes; results in a loss of dendritic spines and a reduction in synapses along the visual cortex
myelination
the formation of the myelin sheath around nerve fibers
what happens when axons have reached their final destination?
they induce nearby glia to ensheath them in myelin
how does myelination affect behavior?
allows neuronal networks to communicate rapidly
