C/B Exam 2 Flashcards
What did Myers and Sperry do and what did they find
severed the hemispheres of cats and monkeys
Found: corpus callosum is the PRIMARY COMMUNICATION HIGHWAY
-also have bilateral structures and homotopic areas
-cats and monkeys 70% of their callosal axons during development
Copus callosum has been severed in ___ patients
split-brain
what is the wada test
anesthetize ipsilateral hemisphere
what happens if you anesthetize LSH
-ability to speak is impaired
LSH functions
-language
-detail oriented
RSH functions
-face recognitions
-emotional prosody (understanding emotions)
-holistic (big-pictured) focused
LH protrudes in the ___ of the brain
back
RH protrudes in the ___ and is chubbier in the brain
front
connecting same structures
homotopic
connecting different structures
heterotopic
-smaller than corpus callosum
-connects temporal lobes areas (amygdala)
-posterior commissure (even smaller)
Anterior commissure
ability to communicate solely to one hemisphere is based on the anatomy of the ____
optic nerve
at the ___ the optic nerve divides in half and the fibers that carry the visual info from the ____ portion of each retina cross and project to the visual cortex of the opposite hemisphere, while the fibers that carry visual info from the ___ portion of the retinal continue onto the visual cortex of the ipsilateral hemisphere
optic chiasma, medial, lateral
in tests of the split-brain patients, experiments restrict visual stimulus to a single ___
hemisphere
when 1 hemisphere initiates behavior that the other hemisphere detects externally giving it a cue about the answer to a test; not intentional
cross cuing
ability to understand that other individuals have thought, beliefs, and desires (that may differ from your own)
theory of mind
theory of mind critical structures
temporal-parietal junctions (TPJ) in the RH
-both hemispheres are engaged
–mPFC amygdala-temporopolar cortex
–pSTS, precuneus
if info about ___ is housed in the RH and isn’t transferred to the speaking LH you might expect impairments in social and moral reasoning
belief attribution
people who have an intact corpus callosum say what about belief attribution
say it was moral they realize Grace had a false belief
people who have a severed corpus callosum say what about belief attribution
say it was morally unacceptable but were often uncomfortable with their answer and tried to justify it
Why is there a difference in moral judgment in severed corpus callosum
-when the LH gives its answers locally, the RH hears the judgment for the first time
-RH’s emotional reaction to the judgment may be surprise and dismay
following a colostomy, what skills remain intact in the LH
-verbal intelligence and problem solving skills
causal inferences and interpretations are a ____ specialization
LH
LH never admits ignorance about RH, always makes up a __
story
does callosotomy prevent emotional info from transferring
no, emotional info transferred subcortically
LH’s interpreting nature can contribute to ______
false memory
-RH and LH can detect familiar stimuli and new unrelated stimuli but LH tends to detect false positives when new stimuli are related
_____ in the RH can also function as an interpreter
illusory contours
-to perceive objects in the environments as unified, one must often extrapolate incomplete info
face perception involved what regions
-fusiform gyrus (right-lateralized, ventral occipitotemporal cortical –VOTC– recognition network)
-FFA (fusiform face area)
face is processed
holistically
perception and recognition are better for faces presented upright than inverted
face inversion effect
where it becomes more difficult to detect local feature changes in an upside-down face, despite identical changes being obvious in an upright face
thatcher effect
inversion impairs the processing of faces more than the processing of than the processing of non-facial objects ex. buildings or cars
face-object effect
humans may be the only species to naturally use the face as the ____ source of info for individuation
primary
-young children process faces in a piecemeal fashion such as eyes, nose, mouth
-holistic processing begins around the age of 10
encoding switch hypothesis
what is the dominant theory regarding the processing
holistic processing — could even precede the development of part-based processing
rare condition where one can’t recognize faces including their own, familiar, and famous people
prosopagnosia
-most cases acquired through brain damage
-deficit it both ANTEREOGRAFE AND RETROGRADE
-possibly through genetic mutation as well
prosopagnosia is a ___ to match sensory input to representations
failure
-due to are facial preception areas being damaged
face perception emerges from ____ and ___
sensory input & recognition
when the top half of one face is aligned with the bottom half of another and presented upright, the resulting composite arrangement induces a compelling percept of a novel facial recognition
**more easily illustrated in studies that use unfamiliar face stimuli compared to familiar
composite face illusion
Pathway of the visual system
Light passes through lends - inverted and focused to project on retina –> Optic nerve –> Optic chiasm –> Thalamus –> Primary auditory cortex –> secondary visual cortex
When do receptor cells become active?
when the stimulus exceeds a minimum intensity level (meets the threshold)
Adjustment of the sensory system’s sensitivity to the current environment and to changes in the environment
Adaptation
How well we can distinguish among stimuli within a sensory modality
ex. telling difference btw hz or smells of fruits = acuity
acuity
-distinguish by:
-stimulus collection system design
-number and distribution receptors
-best in the center of our visual field
-central region of retina is packed with photoreceptors
Visual acuity
rapid eye movement between fixed eyes
Saccades
What does squinting do?
-Makes the pupil smaller which results in better focus
- limits the amount of light that enters the eye
If a sensory system devotes more receptors to certain types of information…
corresponding increase in cortical representation
Benefits of increase in the cortex:
-flexible behavior
-memory capacity
-action and attention
-links many systems
Thalamic connections has:
- many subdivisions
-reciprocal connections with primary cortices
Intra (within) thalamic connections
2 or more senses coming together and working
Multi-sensory integration
when 2 senses collide with one another and lead to misconceptions *
McGurk Effect
Flow of information - audition
1.Sound waves enter auditory canal
2.sound waves get amplified
3. waves hit the tympanic membrane making it vibrate
4. vibrations travel through middle ear and rattle the malleus, incus, and stapes
5. vibrations are sensed by tiny hair cells along basilar membrane of the fluid filled cochlea
does the visual system override the auditory system?
yes
Typanic membrane is the
eardrum
what are the small bone in the middle of the ear
malleus, incus, and stapes
hair cells in the ear
stereocilia
what determines frequency tuning
location of hair cell on the membrane
Spatial arrangement is called ___ which forms a ____
tonotopy
tonotopic map
What do hair cells act as
mechanoreceptors - mechanically gated ion channels allow K+ and Ca2+ to flow in
Loss of hair cells leads to
deafness
Speech and music
-made of complex frequencies activating a broad range of cells
-important for human communication
Subdivision of information in the brain
-primary & secondary areas
-rostral A1 (low frequency)
-caudal A1 (high frequency)
-tuning curves become narrow in the cortex
**Cells response to narrower frequencies of sound
Discrimination of sound
-sharp acuity in humans
- goal = localize sound
- interaural time
where do the auditory nerve project to?
cochlear nuclei
-CN in the medulla
-each auditory nerve fiber splits to synapse in both the dorsal and ventral cochlear nuclei
info travels up to the pons and splits to innervate ______
L & R superior olivary nuclei
-info from both ears is shared here
projects to the medial geniculate nucleus in the
thalamus
after the medial geniculate nucleus, it then goes to the primary auditory cortex in the ____ lobe
temporal
the difference in when sound reaches each ear
Interaural time
auditory cortex can dissect components of sound and integrate then into an entire experience
Music
What kind of processing is feature extraction
bottom up
what kind of processing is feature integration
top down
Components of music
pitch, rhythm, tempo, beat, meter, contour, loudness etc.
distinguished instruments (tonal color) & describes the way a single instrument can change sound as it moves across its range
Timbre
the brain represents it directly
Pitch and the brain
Tapping along, keeping time
cerebellum
performing music and planning
motor cortex and frontal lobes
tactile feedback you’ve pressed the correct key
somatosensory cortex
audio feedback you’ve pressed the correct key
auditory cortex
reading music
visual cortex
recalling lyrics
language areas
emotional experience
amygdala, NAC, and VTA
orienting experience
anterior cingulate cortex, hippocampus, and PFC
distinguishing timbre
superior temporal sulcus
Temporal lobe epilepsy
musical hallucinations
Why do we get chills sometimes when we listen to music?
The autonomic fear-based response gets activated
The autonomic system cannot be shut down - cognitive interpretation in the cortex can inhibit the fear and allow us to experience pleasure bc we know its not dangerous
David Huron’s theory
a cultural practice that leads to a lasting genetic change
Gene-culture coevolution
Do tamarins and marmosets prefer silence or music
silence
What indicated that humans and chimpanzee share evolutionary history in context of music
both prefer music of silence
-visual and somatosensory information gets distorted
-we know less about smells and taste
-sounds seem to stay coherent
Auditory perception in dreams
perceiving info at a distance
remote sensing (exteroceptive perception)
light passes through the ___ of the eye
lens
image is inverted and focused to project onto the ___
retina
what are the densely packed layers of neurons
retina
the deepest retinal layer is composed of ___ containing ___
photoreceptors; photopigments
low light; evenly distributed and active at night
rods
color- densely packed near the center (FOVEA), active during the day
Cones
responds to short wavelengths (blue part of the spectrum)
short cones
responds to medium wavelengths (greenish part)
medium cones
responds to long wavelengths (reddish)
long cones
light-sensitive proteins
photopigments
low light contrasts — found in rods
-when exposed to light, proteins split apart
- destabilization alters membrane potential of the photoreceptors
- triggers AP in downstream neurons - transduction
rhodopsin
color vision - found in cones
photopsin
connected to BIPOLAR NEURONS that synapse with GANGLION CELLS
-info is compressed
rods and cones
ganglion axons bundle to form ___
optic nerve
cross-over of info occurs at the
optic chiasm
90% of axons in the optic nerve are involved in ____ pathway
retinogeniculate
what is the retinogeniculate pathway
retina –> optic nerve –> optic chiasma –> thalamus
what is the geniculocortical pathway
thalamus —> primary visual cortex –> secondary visual cortex
the region within the visual field in which stimulation affects neuron’s response
the receptive field of a neuron
receptive visual fields form ___
topographical (retinotopic) maps
on-of edge detectors in V1
-receptive fields are circular with on-off regions
-when the cell is active, not only indicates position of stimulus but also retention of stimulus edge
fussy cells
-cells in the retina and LGN respond best to small spots of light
-cells in V1 are sensitive to edges
-V4 & TE optimal stimulus becomes more complex ex. shapes or faces
visual areas
-LGN receptive field -a very limited region of space, less than 1 degree of visual angle
-cells in V1 – slightly larger receptive fields ranging up 2 degrees
-magnification process continues through the visual system
receptive fields become larger across visual system
-don’t respond to color
-responds to movement and direction
-this cell responds preferentially to down and left
-responds maximally when the stimulus is moved quickly
-stimulus must be in the receptive field
MT (V5) cells
genetic- recessive gene on x-chromosome –> higher prevalence in males
color blindness
3 cones working together to determine what color you’re looking at; not colorblind
trichromacy
all 3 photopigments are present but one exhibits abnormal sensitivity
anomalous trichromats
-pretanomalu (L cone is impair)
-Deuteranomay (M cone is impaired)
red green colorblindness
trianomaly (s cone impaired)
blue yellow colorblindness
-individuals with only 2 photopigments (protanopia, deuteranopia, tritanopia)
dichromats
missing photopigments sensitive to either medium or long wavelengths
dichromats red green
missing photopigments sensitive to short wavelength (very rare)
dichromats blue yellow
-involves a lesion to V4
-decreased acuity
-partial or total absence of color vision
-may be uncomfortable in bright environments
achromatopsia
loss of motion detection, view the world as a series of snapshots
akinetopisa
-perception is a synthetic process
-coherent representation
-coherence sometimes involves distorting the sensory info to make it all make sense
multimodal perception
-multimodal site
-topographical maps of visual, auditory, and tactile info
-contains cells that respond more when presented with multimodal stimuli
-spatial and temporal coincidence detection for integration
superior colliculus
-projection to and form sensory cortices
-responses to visual, auditory, and somatosensory stimuli
-active in lop reading when sound matches the movement
superior temporal sulcus (STS)
-audiovisual (somatosensory integration)
-theory of mind – mentalization
-motion perception
-speech processing
-processing faces
-propose that the function of the STS varies depending on the nature of network coactivations with different regions in the frontal cortex and medial-temporal lobe
-keeping with the notion that the same brain region can support different cognitive operations depending on task-dependent network connections, emphasizing the role of network connectivity
the chameleon of the brain
auditory and visual stimuli can enhance ____ in the other sensory modality
perception
-TMS over visual cortex – increased response time to the auditory cortex
-TMS at the subthreshold level – phosphenes were only visible when auditory stimulus were presented
when were phosphenes visible
when auditory stimulus were presented
when senses are mixed
synesthesia
-most common form is grapheme-color/or colored sequence (better at color discrimination)
-aberrant cross-activation of one cortical area by another
-hyperactive sensory system – one hypothesis
-visual processing areas may be organized in a more distributed way – not confined to the visual cortex
-potentially more white matter
deaf individusals show activation in the auditory cortex in response tp ___ and ___ stimuli
tactile and visual
there is an increase in ___ ___ volume in deaf people with enhanced visual perception
planum temporale
cross-modal plasticity only occurs when disability is ____
congential
what brain regions are involved in moments of insight
-right superior temporal gyrus
-right parietal cortex
-(right parietal lesion –> loss of artistic sense)
a burst of activity seen just prior to the creative insight suggests what?
some level of unconscious info-integrating processing
what brain regions are involved in math problem solving
-frontal. right temporal, and parietal lobes
what brain region is involved in impulse control
DLPFC
what happened when jazz musicians improvise
deactivation of DLPFC
-dyslexic (impairment in LH)
-prosopagnosia (impairment in RH)
-adept at drawing
-portrait artist
-left-handed (RH dominant)
chuck close
damage to what hemisphere can enhance creativity
LH
-“mental time travel” – future thinking
-autonoetic consciousness
-distinction btw episodic and semantic memory
endel tulving
acquisition/encoding
learning
retrieval/recall
memory
new info enters the brain along pathways btw neurons in the appropriate area of the brain. Here attention pay the key role in receiving and encoding the info
-sensory info comes in being filtered, some info will go onto STM or LTM
acquisition
if you pay attention well enough to encode new info in your brain, you brain sends signals to store the info as long-term mem. It is more easy to retain info if it is related to something you already know or if it stimulates an emotional response
-stabilization of memory traces via placisticy
-how mems go from STM–> LTM
-occurs at the cellular level (protein synthesis dependent, synaptic consolidation)
consolidation
recalling info, your brain has to activate the same pattern of cells it used to store it. The more frequently you work the info the easier it is to retrieve it
retrieval
Sensory memory for auditory info
echoic mem
Sensory memory for visual info
iconic memory
a small amount of info that can be held in mind and used in the execution of cognitive tasks
-contents can be obtained from sensory memory from LTM
*distributed across the cortex
*Research shows that oscillatory synchrony of these areas may underlie __
WM
What is the main difference between STM and WM
WM is used in cognitive tasks and does not involve the hippocampus
What do both STM and WM activate?
prefrontal, cingulate, parietal, sensory cortices, and basal ganglia and thalamus
-involves WM
-individuals w shizo have impairments with this task
-measures many things including attention and visual processing
Wisconsin Card Sorting Test
What did the WCST Test determine
that there is a PFC deficit in schizophrenia
Sensory inputs –> sensory registry + w/ attention –> short term storage + rehearsal –> long term storage
- info can be lost by decay or interference
Atkinson and Shriffin Modal Model of Memory
Damage to left perisylvian cortex - showed impairments in STM using digit span test.
- able to form LT associative memories w a word text
- shows dissociation between STM and LTM
-STM MAY NOT BE REQUIRED TO FORM LTM
Patient K.F
-Damage to left angular gyrus
- deficit in STM but preservation of LTM
- info may be encoded directly into LTM from sensory memory registers
*double disassociation
Patient E.E
-central executive mechanism that presides over coordinate interactions b/n 2 subordinate STM stores and LTM
- phonological loop and visiospatial “sketch pad”
Baddeley and Hitch WM Model
acoustic code - recall of words better when they dont sound similar (interference)
-suggests that WM uses acoustic code rather than semantic code
Phonological loop
acoustic code - recall of words better when they dont sound similar (interference)
-suggests that WM uses acoustic code rather than semantic code
Phonological loop
people perform better when instructed to use visual imagery to remember a list compared to a verbal memory strategy
- if verbal interference introduced - impaired in using this strategy
Visiospatial “sketch pad”
(left supramarginal gyrus)
- have deficits in phonological working memory
-can’t hold strings of words in WM
Lesion in Brodmann area 40
what part of the brain involves the phonological loop
-left premotor area (brodmann area 44)
-lateral frontal
-inferior parietal lobes
How is WM maintained?
rhythmic synchrony of brain oscillations
-Sustained representations
WM = not as persistent in spiking
Sustained representations
Why does WM have a limited capacity?
With too much activity there can be interference. Limited because of the coding scheme
spikes “refresh the memory”
-memories held by persistent spiking alone can be liable because they are lost when activity is disrupted
*models of persistent spiking have trouble holding more than one memory at a time
activity silent models
as WM capacity is exceeded the less neural activity there is –> spreading too thin
resource model
only so many slots, phenomenon is all or none – stimulus is encoded (remembered) or not, no partial info is acquired as u see in the resource model
slot model
___ requires less space in in WM
chucking
impairments in the ability to CONTROL contents of WM
-impairments in this ability can results in ___ ex. anxiety, schizo
pathology
info retained for significant amount of time
-divided into declarative and non-declarative
LTM
aka explicit memory; memory for events and facts, both personal and general to which we have conscious access and can verbally report it
declarative mem
endel tulving proposed declarative mem be parsed into ___ and __ mem
episodic and semantic
comprises memories of events that the person has experienced that include contextual elements ex. what happened, where it happened, when and with whom
*EXPERIENCE
episodic
memory that pertains to yourself and can be episodic or semantic
autobiographical mem
objective and factual knowledge
semantic mem
-cannot be expressed verbally -don’t have conscious access
-aka implicit mem
ex. priming, conditioning, habituation, sensitization, and procedural mem
non-declarative mem
-motor skills
-cognitive skills such as reading
-ability to form habits
-depends on extensive and repeated experience
procedural mem
procedural mem relies on ____-____ ganglia loops
cortical-basal
exposure to one stimulus (priming stimulus) subconsciously influences a response to a subsequent sequence (target sequence
-acts within the PERCEPTUAL REPRESENTATION SYSTEM: specific for sensory modality of the learning and test phases
-medial temporal independent
priming effect
based on the meaning of a stimulus and is enhanced by semantic tasks. For example, the word table will show ___ priming effects on the word chair, because the words belong to the same category
not consciously aware of it
conceptual priming
prime and target are different words from the same semantic category
ex. dog and wolf
semantic category
Conditioning an individual to respond to a certain US
Classical conditioning
CS and US overlap, CS starting first and both ending at the same time
Delay conditioning
CS precedes YS
- Gap between when CS ends, and US presentation begins
Trace conditioning
Delay is HPC ___ and trace is HPC ____
independent; dependent
diminishing of a physiological response to a repeated stimulus
Habituation
used to study fear related behaviors
Fear conditioning
-developed a novel theory for sensory habituation
-propose that memory engrams for habituation experience may be ensembles for inhibitory neurons forming to provide a “negative image” of the excitatory ensembles that mediate the perception of environmental stimuli
Cooke and Ramaswami
- if the stimulus is withheld, the response tends to recover over time (spontaneous recovery)
-the weaker the stimulus, the more rapid and/or more pronounces is habituation - strong stimulation may yield no significant habituation
-habituation to a given stimulus exhibits stimulus generalization to other stimuli
-presentation of another (usually strong) stimulus results in a recovery of the habituated response (dishabituation)
-habituation is gated - occurs less efficiently if reward, punishment, or strong emotional engagement occurs together with stimulus exposure
-long term habitation requires de novo protein synthesis
Characteristics about habituation
enhancement of a physiological response to a repeated stimulus - the organism becomes more responsive to the same stimulus
Sensitization
a tactile stimulus applies to the siphon elicits a gill ______ reflex
withdrawal
processing of incoming info which creates MEMORY TRACES or “ENGRAMS” via biochemical changes synaptic strength and connections
-2 step process – gazzaniga
encoding
retention (preservation) of memory traces, opp. of decay
storage
successfully accessing memory traces for use; drives decision making and behavior
retrieval
what are the two findings that claim memories are consolidated
(1) brain trauma - patient H.M; post traumatic amnesia
(2) Resection of the hippocampus caused anterograde and retrograde amnesia
inability to remember the past (damage to cellular networks holding those memories)
Retrograde amnesia
inability to form new memories (cells not getting enough oxygen/processing like encoding & attention affected/impaired sleep)
Anterograde amnesia
i. hit his head at 7
ii. seizures at 10
iii. hippocampus removed at 27
retrograde 16 - 27
anterograde 27 - death
Patient H.M
oldest memories survive the best
Ribot’s Law
the process by which the hippocampus guides the reorganization of the info stores in the neocortex such that it eventually becomes independent of the hippocampus
system consolidation
What part of brain is important for working memory?
parietal and frontal cortex
Neurosurgeon who performed bilateral hippocampal resection surgery on H.M (remove only one HPC today if needed)
William Scoville
neurosurgeon known for his work on the cortical homonculus, hallucinations, & deja vu
Wilder Penfield
neurons fire at random –> results in false sense of experiencing familiar situation that had previously been experiences
Deja vu
primary student who studied H.M after his surgery
Brenda Milner
What is the assumption of systems consolidation
new memories require the HPC - however old memories don’t depend on the HPC which is why they are preserved
process by which HPC guided reorganization of info stored in the neocortex such that it eventually becomes individual of the HPC
(standard model)
system consolidation theory
organized group of past experiences –> like an archetype or motif
schema
old memories still depend on the HPC but are more resistant to disruption because they have more opportunity to be reactivated
-each reactivation generates another index in the HPC and because these copies are distributed, even in cortical areas, the memory can survive partial damage
multiple trace theory
-representational reinstatements of an episodic memory trace upon receiving only a partial cue
-generating an entire memory from only part of the memory trace (i’ve seen this before)
-CA3– recurrent collaterals
pattern completion
-representational orthogonalization (separation) of episodic memory traces upon highly similar inputs (leading to a high degree of mnemonic discrimination for similar events)
-the ability to store and disambiguate events that are highly similar by using a code in the brain where the cells that correspond to those events are memory traces that are completely unique
-dentate gyrus
-_____ ____ relies on sparse coding scheme in the DG compared to cortex involving low basal activity, a high degree of inhibition, and millions of neurons
pattern separation
loop - first describe by Cajal using Golgi staining method
Tri synaptic circuit
granule cells in the__
DG
mossy cells
parametal neurons
pyramidial neurons in ____
CA1/CA3 = Schaffer collaterals
EC –> DG
perforant path
DG –> CA3
mossy fibers
the phenomenon where adults have difficulty recalling memories of early childhood
Infantile amnesia
developed his theory based on the observation that his adult patients rarely recalled memories of their first years of life (before 6-8 years)
Freud & infantile amnesia
absence of memories
Age 0-3 memories
spotty recall of memories
age 3-6
When does memory begin to develop
24-36 months of age
cortex is not “online”
-Pillemmer and white & Nelson
Immature brain
-Tulving and Thompson
being in the same state to remember a specific memory
State dependency & memory
continuing of neurons forming disrupts established memories
-regulates the ability to form enduring HPC-dependent memories
neurogenic hypothesis
facilitates the formation of new memories by increasing capacity and reducing interference between old
-ability to block irrelevant information reduces demands when trying to recall important information
adaptive forgetting
-Highly superior autobiographical memory/hyperthymesia
-inability to forget anything
-an extremely rare condition
HSAM
exceptional memory - extremely vivid associations of visual imagery.
-made mistakes due to perceptual problems, not a memory lapse
*REMEMBER THINGS SEPARATELY
Patient S
set of cells involved in memory
Engrams
-contextual representations and engrams
-searched for the location of a specific engram for a maze environment in the rat brain
Karl Lashley
Engrams are distributed (____) and cortex works as a whole (___)
-equipotentiality
-mass action
excitability and engram allocation
CREB
NEURAL NETWORK THEORY
- memory resides in CELL ASSEMBLIES; synapses can be strengthened or weakened
-strengthening synapses resulted when a weak and a strong input act on a cell simultaneously (coincident detection – associativity/cooperativity)
donald hebb
stimulating axons of the perforant path resulted in long-term increases in the magnitude of EPSPs – granule cell response was larger with subsequent stimulation
*NEED DEPOLARIZATION TO OCCUR
* increase calcium in cells leads to decrease ___ and hyperpolarization
long term potentiation
when pulses are presented slowly —> ___
LTD
Where does LTP occur
hippocampal regions (mossy fibers & Schaffer collaterals), amygdala, cerebellum, basal ganglia, and cortex
receiving more than one input at the same time
Cooperativity
weak inputs potentiated when they cooccur with stronger inputs ex. classical conditioning
*cells that fire together wire together
Associativity
only the stimulated synapse is potentiated
-post-synaptic cells must be depolarized
-if the cell is hyperpolarized, LTP is prevented
-when postsynaptic inhibition is prevented LTP is facilitated
-involves de novo synthesis
specificity
what must occur for specificity
post-synaptic cells must be depolarized
-if the cell is hyperpolarized, LTP is prevented
-when postsynaptic inhibition is prevented LTP is facilitated
-involves de novo synthesis
Receptors involved in LTP
interactions between glutamate AMPA and NMDA receptors
NMDARs vs AMPARs
-NMDARs => critical for producing LTP + voltage gated
-AMPARs => maintaining LTP
What can happen if you block NMDAR
prevent LTP and impair learning
certain hippocampal cells firing only when animal is in a specific location
Place Cells
The geographical location of place cells
place fields
fire in multiple positions which creates a hexagonal firing pattern
-located in the major HPC input region, the entorhinal cortex
Grid Cells
neurons increase their firing rate during sleep T or False
true
re-occurance of sequence of cell activations that also occurred during learning
–>can be in same order or reverse; typically when sleeping
–> thought to be involved in systems consolidation
–> NREM only
Hippocampal replay
local field potentials are interrupted by short bouts of high frequency
Ripples (sleep)
sequences of activations that occur before the actual activity in a way that predicts the sequences
preplay
can we learn while sleeping
yes; we can remember the locations of the sounds that were presented during the sleep
involves cortisol and norepinephrine (associated with mammalian stress response)
Sleep and memory consolidation
How can stress affect memory consolidation?
it can potentiate memory through reconsolidation which is a period of time where your memories are modifiable when they are reactivated.
Chronic stress can lead to…
impairments in memory consolidation via high conc. of glucocorticoid receptors in the CA1; atrophy in hippocampal volume; higher risk of Alzheimers
-memories can change (experience dependent)
one way is reconsolidation
Memory malleability
engram –> memory box
-reactivation, destabilization, and reconsolidation
Dynamic Memory Engram Life Cycle
