cogs 107a final
labeled line model
each cell represents a taste quality and communicates info to the CNS separate afferent pathways to the gustatory corext
one odor** receptor cell but each receptor responds to a range
each olfactory sensory neruron expresses
10th (vagus) cranial nerve
epiglottis and down into gut
how is vertical cleft formed
even amount of notch 1 and numb
what happens if K channels are blocked from PKA low gK
extended depolarization prolongs the action potential - more ca comes in - more transmitters
5 prolific positions
extension migration - DNA replication return to ventricular surface retraction divison (stay or go)
ionotropic
fast and brief mediates behavior
advantages of working with invertebrates
small nervous systems large neurons identifiable neurons and circuits simple genetics
supporting cells
similar to glia help produce mucus
olfactory receptor cells
site of transduction
metabotropic
slow and lasts long changes quality of behavior
other things that help you taste
tongue mouth palate pharynx epiglottis
analog signal intensity
transformed into a digital pulse code
circumvallate
type of papilla
thalamus regions
ventral posterior medial (bottom, back, midline) -
how to communicate sensory info
- receptor cells make contact sensory axons from CN 10, 9, 7
cell activated during associtie learning
5HT
NMDA is a function of
AMPA
purinergic
Atp receptors are called
how does cAMP effect protein kinases A
Causes subunits to dissociate
CNS
Cb1 is in the
what mediates bitter
G Protein coupled receptor families (GPCRs) type 2 ATP
transduction mechanism for bitter, sweet, umami
G protein activates phospholipase -c increases synthesis of IP3 OP3 triggers release of Ca, and taste specific Na channel opens membrane depolarizes and xmtr releases(ATP) diffuses through ATP permeable channels
no
are taste receptor cells neurons
NMDA channels
Mg acts as a voltage sensor at resting membrane potential, Mg++ is stuck in the channel as the membrane is depolarized (flow of ions in AMPA) Mg is dislodged and the current can flow NMDA is also permeable to Ca++ magnitide of Ca is proportional to the co activation levels of the pre and post synaptic cells at the synapse
Hebbian learning rule #2
Neurons that fire out of sink lose their link
role of creb
PKA phosphorylates creb is a transcription factor helps to grow new synapses
facial nerve (7) anterior part of tongue
PNS can have fibers that do different functions - somatic - movement - special sensory - taste
CB2
PNS, immune, and metabolic
NMDA acts like
a voltage sensor (mg block)
ventrical zone
above ventricular surface
coincidence detector
adenylyl cyclase acts like a __________ in classical conditioning
1 olfactory nerve
alfactory system is mediated by this cranial nerve
receptor potential
amplitude and duration tells us about the stimulis
7th (facial) cranial nerve
anterior (tip) of tongue
taste receptor cells
apical near surface of the cell chemically sensitive to TRC microvilli project into the pore synapse onto gustatory afferent axons chemical and electrical synapses onto basal cells
3 phases of pathway formation
axon chooses the correct path (cross or stay the same) determine where to stop (target) must synapse at the correct spot (info you transmit should be meaningful)
marginal zone
below pial
induction of LTP
biochemical reactions that come out of tetanic stimulation
olfactory receptor cells are
bipolar olfactory neurons penetrates into CNS axons bundle and become cranial nerve
CREB 1
cAMP response element binding protein
what makes adenylyl cyclase
ca binding to calmodulin
molecular basis for clasical conditioning in Aplysia
ca is elevated and adenylyl cyclase increases cAMP more cAMP- more PKA - phosphorylates K channels -- decreases K current decreased gK-- prolonged AP-- more CA is released increased post synaptic response
why does sensory neurons activity have a specific effect on sensory experience
central connections not bc of taste receptor that evokes the activity
what do classes of receptor cells do
changes one type of stimulus into electrical signals that are encoded as action potentials
pain
chemo and mechano
4 types of guidance mechanisms
chemoattraction - contact and attraction - netrin chemorepulsion - contact and repulsion - slit and robo
transforms smell, taste
chemoreceptor
what determines if daughter cells stay or go
cleavage plane determines distribution of transcription factors vertical - both stay and replicate horizontal - top daughter migrates
how we perceive complex flavors
combination of chemoreceptors with different strengths for ligands
subplate
contains the first neural precursor cells to migrate from the ventricular zone and is transient
papilla
contains the tastebuds
habituation and importance
continued stimulus lessons the response learns what it can safely ignore important for
endocannabinoid system
controls excitatory behavior on a synapse by synapse level
types of memory
declarative -- facts, events, places cerebral cortex (conscious memory formation) procedural -- motor skills, habits striatum/ basal galglia
long term habituation is caused by
decrease in amount of synaptic contacts between sensory and motor neurons
important parts of the hippocampus
dentate gyrus - direct pathway -CA1 neuron layer 3 of Entorhinal cortex -trisynaptic pathway - different part of CA1 layer 2 of Entorhinal cortex perferant pathway
ubicutin
destroys response subunit
ventricals out
direction that brain develops
distributive model
each cell detects all tastes and the CNS makes sense of all the input (tells which is strongest)
how do daughter cells know where to migrate
form subplate - helps with migration but doesn't stay there forever next batch of cells form layer 6 5th layer is formed by going through the 6th layer but never the cortical plate
stimulis intensity
frequency is proportional to
non associative learning
habituation sensitization
Protein Kinase A
heterotetrameric enzyme that consists of two regulatory subunits and two catalytic subunits
LTD or LTP depends on
how much ca comes in
Salt- Na has inward current Sour blocks because K is permeable to hydrogen- faster membrane depolarization
how to distinguish salt and sour
perception
how we perceive it
how to tastes help us
identifies dietary components salt- electrolytes sour- protects - can be bad on the gut bitter- toxin detector sweet- energy rich umami - glutamate
G protein coupled receptor**
in resting state, G protein binds to a molecule of GTP when transmitter binds to receptor exposes a binding site for the G protein G protein comes over and binds to receptor GTP phosphorylation (activated for GTP GDP exchange) changing GDP for GTP causes subunit to dissociate which exposes a binding site of adenylyl cyclase produces many molecules of cAMP which is converted to ATP
ageusia
inability to detect taste qualties
anosmia
inability to smell
long term potentiation
induced by synaptic activity homosynaptic -- one synapse
amiloride sensitive Na channel s
insensitive to voltage (concentration drives) like a leak channel, stays open
how are the cortical layers formed
inside out 6 to 5 to 4...
sensory receptors encode
intensity of the stimulus by looking at the frequency
glutamatergic receptors
kainate AMPA -Na NMDA - voltage gated Mg2 clogs groups of metabrotopic glutamate receptors
expression of LTP
long term changes that take place in the synapse AMPA receptor is inserted into postsynaptic cell so nextime glutamate is released there is a higher chance of opening MNDA
pyramidal neuron
looks like a pyramid apical dendrite that goes straight up
where do cranial nerves synapse
low in the brainstem nucleus of solitary tract (glustatoty cortex) goes through the thalamus go upward to cortex (insula-- activated with disgust, primary gustatory) hypothalamus and amygdala
sensitization and purpose
meaningful strong stimulus heightens responses learned fear -- survival
transforms touch
mechanoreceptor
where is explicit memory stored
medial temporal lobe
modifiable synapses are
modifiable in both directions
Eric Kandel
molecular mechanisms that lead to synaptic plasticity what is the physical basis
more Ca signaling same amount of glutamate has a better chance of having Na coming in so there is a higher EPSP
more AMPA receptors results from and causes
nasal
nasal or temporal crosses
guidance cues
neuron goes to corresponding receptors
Hebbian learning rule #1
neurons that fire together wire together when presynaptic neuron is activated at the same time as postsynaptic (from another neuron) then the synapse is strengthened
when os endocannabinoid really important
newborns, puberty
distributed memory storage
no single neuron represents a memory allows for graceful degradation of memories
mossy fiber LTP what mediates
not NMDA PKA* phosphorylates proteins at the snare complex where vesicles dock and more transmitter is released
where are odor molecules detected
odorant receptors in olfactory cilia
first order neuron
sensory neuron that delivers sensations to the CNS
what mediates salt and sour
serotonin
olfacory transduciton
odorants find to ordoratn receptor proteins Golf stimulation activation of adenylyl cyclase formation of camp using ATP opens Ca and Na channels ca activates cl channels (normally causes IPSP but this is EPSP due to the concentration) membrane depolarization (receptor potential)
3 types of cells in the ofacotry epithelium
olfacotry receptor cells supporting cells basal cells
how is horizontal cleft formed
one daughter has all the notch and migrates
classical conditioning
one stimulus (CS) predicts another (US)
omnivore
opportunistic eaters
inferotemporal cortex area IT responds to complex shapes and images
part of brain that responds to faces
transforms light
photoreceptor
sensation
physical component
perferant pathway
pokes holes to become direct or trisynaptic pathway allows for multimodal sensory and spatial info
strong NMDA activation means
post synapse is strengthened
retrograde endocannabinoid signaling
post synaptic tells pre to stop synthesized when there is too much is a lipid so it is not bound by membranes and diffuses into extracellular space Cb1 receptor receptors it - Gprotien - intercellular signaling block ca channel on presynaptic channel - cannot release transmitter contents
9th (glossopharyngeal) cranial nerve
posterior - back of tongue
central olfactory pathways
receptor neurons - olfactory bulbs olfactory axon synapses on second order neurons in the glomerulus second order neurons send axons through olfactory tract
rapidly adapting mechanoreceptor
responds at the beginning and the end of the stimulus
instrumental learning
reward and punishment
how they know what neuron to become
semaphorin 3a-- apical dendrite grows toward dendrite grows away GROWTH CONE filapodia contain chemical sensors that help it know where to go lamelpodia
olfactory epithelium looks like a qtip
sense of smell is dependent on this
flow of sensory info into long term
sensory experience (memory acquisition) -- short term (memory consolidation) -- long term mem
mixed nerves
somatic and visseral carry info from different regions of the body to the CNS
glossopharyngeal (9) different functions
somatic motor - movement of muscles in the throat visceral motor - control of salivary glands special sensory - taste on posterior (back) 1/3 of the tongue visceral sensory - detects blood pressure
basal cells
source of new receptor cells
where is the physical change during habituation
still is an action potential less glutamate is released and receptors maintain sensitivity
ltm in sensitization
synthesis of new proteins alterations in gene expression growth of new synaptic connections
excitatory amino acid transporters
take up glutamate (excitatory amino acid) -- too much leads to too much ca exist on astrocyte, pre, and post only work under normal conditions how endocannabinoid system helps
mechanisms of taste transduction (salt examples)
tastant channel permeable to NA Na diffuses in according to concentration gradient sensitive to amiloride as it is depolarized voltage gated na and ca channels open serotonin is released (5HT)
slowly adapting mechanoreceptor
tells the entire period stimulus is present
transforms thermal
thermal receptors
Ca
what activates taste specific ion channel
NMDA activation
what determines how much ca comes in
G Protein coupled receptor families (GPCRs) type 1 ATP
what mediates sweet, umami
camp cyclic nucleotide gated ion channels
what opens Ca during olfactory
why do the neurons from each eye grow together
when they are neighbors there is correlated activity (left goes to a, right goes to b) patterned spontaneous activity also determined by what the visual field is seeing
pial zone
where DNA replication happens