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Neurophysiology > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

Cognitive Neuroscience

A

Study of the underlying mechanisms of cognition

Overlaps with cognitive psychology, neurophysiology, psychiatry, neurobiology, neurology, etc.

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2
Q

Anne Greene and Dr. Willis

A

Accused of murdering her baby, sentenced to death. Hung for 30 minutes and her body was promised to two doctors for autopsy. Within 12 hours she was speaking. Walk talk eat after a week.

Dr. Wilis that was supposed to do the autopsy became famous after this event and began teaching at Oxford, later coined term “neurology”. Performed autopsies on those that he treated and connected individual differences with neuroanatomy

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3
Q

How is neurology studied today

A

Functional neuroimaging
Electrophysiologic expermients
Cognitive genetics
Traditional clinical studies

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4
Q

Building the brain

A

genetics and experience help to inform some of the process
Synapses are crucial as they can reversibly connect sets of neurons (neural networks/assemblies)
Networks are composed of neurons that fire together. Building blocks of cognitive function

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5
Q

Neural networks

A

All cognitive functions are attributed to functioning of neural networks
Synapses are able to wire together large numbers of widespread neurons

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6
Q

Nature with nurture

A

Genetics:
lays neuronal groundwork
apoptosis
Variability in genomic plan

Experience:
refinement of neural system
Stimuli will alter synapses
“wiring by firing”

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7
Q

Neuronal change over time

A

Begin with genetics and after birth enter refinement until death

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8
Q

Neural development overview

A

Embryonic ectoderm gives rise to the nervous system
CNS forms the neural tube
PNS forms the neural crest
Prior to birth neurogenesis is mostly complete
Differentiation of neurons and neuroglial cells begins following development of the neural tube into a rudimentary brain and spinal cord

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9
Q

Neuron differentiation overview

A

Neurons differentiate first and the neuroglial cells
BEFORE THEY DIFFERENTIATE neurons and glia must travel to their final locations
Reaching their terminal location is necessary for their survival as they must form PARTICULAR synaptic neurons
IF NOT they undergo apoptosis

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10
Q

Migration of neurons

A

Follow signal transduction molecules and cell surface and extracellular adhesion molecules
Some are chemoattractants and other are chemorepellants
Molecules also guide growing axons

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11
Q

construction of synapses

A

Appropriate synaptic connections must be made following neurogenesis and migration
Signaling molecules allow the axonal growth cone to correctly identify the path to take
Growth factors assist with the growth of the axon, formation of the synapse and altering the number of connections

Failure to form aan appropriate synapse results in the loss of the axon (trophic nature of the synapse involves growth factors including Protein Nerve Growth Factor

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12
Q

Hebbian Assemblies

A

Conversion of the growth cone to a presynaptic specialization circuitry can be established
Forming new and modifying existing networks follows the same principles and utilizes the same mechanisms as Hebb’s synaptic plasticity

Long term Potentiation and Long Term Depression

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13
Q

LTP

A

Requires simultaneous presynaptic and postsynaptic neuronal firing (glutamate and NMDA receptors)
Large amount of Ca ions enter the postsynaptic neuron
Induce LTP by initiating STP and activating protein kinases

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14
Q

NMDA receptors

A

BOTH ligand gated and charge gated

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15
Q

LTD

A

Requires asynchronous firing of pre and post-synaptic firing
Requires glutamate and its NMDA receptor
Small influx of Ca ions, initiation of STP, activation of protein phosphatases

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16
Q

LTP vs. LTD

A

Both require activation of NMDA receptors and entry of Ca into the post-synaptic cell
Main difference is the amount in the post-synaptic neuron
Small influxes = depression
Large influxes = potentiation

LTP relies on the activity of protein kinases
LTD relies on the activity of protein phosphorylases
Often activate and inactivate the same complexes

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17
Q

Types of neural connections

A

Serial - Arrangement of neurons within an assembly that is linear; Vulnerable to damage

Distributed - Arrangement of neurons within assmebly that contain multiple interconnections. More resilient to damage

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18
Q

Excitatory Connections

A

Feedforward excitatory connection: low level –> High level
Feedback excitatory connection: Stimulation of postsynaptic neuron (high level –> low level)
Lateral excitatory connection: Stimulates other presynaptic

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19
Q

Inhibitory connections

A

Feedforward inhibitory - signals one neuron to inhibit another neuron.
Feedback inhibitory - stimulate another neuron that stimulates a neuron that inhibits the original neuron
Lateral inhibitory - similar to other lateral

Produces a signal that causes signaled neuron to release inhibitory signal

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20
Q

Disinhibition

A

Inhibiton of inhibition leads to excitation

For example: the globus palladus is typically an inhibitor. The caudate nucleus inhibits the globus palladus and leads to an over all stimulatory effect on thalamus)

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21
Q

Divergence stream

A

One stream to many others

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22
Q

Convergence stream

A

Severasl neurons to one

convergence and divergence may occur at the same neuron
Lots of convergence of rods, little convergence in cones

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23
Q

Circuit types

A

Hierarchecal circuit

Local circuit

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24
Q

Hierarchecal circuit

A

Each level is regulated by local circuits and three types of processing occur in circuits

Serial processing: info flows from one area to another in the sequence
Parallel processing: Info flows side by side
Reciprocal processing: info flows back and forth

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25
Q

Local circuit

A

Circuits found within heirarchechal circuits
Alter processing at each level. can also determine information passed to the next stage

Local circuits include: Feedforward and feebackward connections. Excitatory and inhibitory connections

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26
Q

Number and complexity of synaptic neurons

A

Cortex contains 90 billion neurons
75% pyramidal neurons
25% stellate neurons

w/ divergence: 18,000 synapses from a single pyramidal neuron; 10,000 per stellate neurons

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27
Q

Connectomics

A

mapping all of the interconnecting circuits of the nervous system
“brainbow” genetic marker that color codes neurons

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28
Q

Cells of the nervous system

A 
Neurons
Neuroglial cells (non-neuronal cells that perform various functions. Outnumber neurons by a factor of 10)
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29
Q

CNS Neuroglia

A

Oligodendrocytes - During development these cells send out processes to contact nearby neurons and form myelin sheaths

Astrocytes - Many functions (other card)

Microglial cells - Small somas and numerous processes. Mediate immune response in CNS. Able to divide. Phagosytose degenerating cells that are undergoing apoptosis. During development they aid in fiber tract development, gliogenesis, and angiogenesis by secreting GF. Antigen presentation. Become reactive and phagocytic in pathogen in the CNS of an adult.

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30
Q

Astrocytes

A

Starlike cells with multiple processes.
Produce ECM proteins and chemicals that guide neurons during migration. Secrete growth factors that regulate morphology, differentiation, and proliferation of neurons (survival).
Maintain tight junction of endothelial cells to promote blood-brain barrier. NT removal from synaptic cleft via uptake.
Sequester metals and neurotoxic material away. (detoxify)
Generates intracellular Ca waves for intracellular and potentiatally intercellular signaling

May increase the numbers of astrocytes and recruitment in response to injury, disease and can form glial scars

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31
Q

Schwann cells

A

Exist in PNS
Generate myelin in the PNS. One Schwann cell will only produce one myelin sheath segment.
Secrete extracellular matrix components to create a sleeve
Respond to neural injury by secreting GF, removing debris from site, provide structural support and guidance to regenerating axon.

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32
Q

Neural triad

A

Neurons
Glia
Vasculature

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33
Q

Cerebral Vasculature

A

Contributes to neurogenesis
Transports O2 and nutrients into the brain and removes metabolic waste and CO2
Endothelial cells interact with astrocytes to form the BBBarrier

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34
Q

Tripartite synapse

A

when an astrocyte process contacts both the presynaptic and postsynaptic portion of two synapsing neurons
Ca is released from storage in the astrocyte in response to metabotropic receptor activity (initiates an STP that releases Ca)

Changes in intracellular levels of Ca results in the release of glutamate, ATP, D-serine (gliotransmitters)
Not an all or none principle. There may be only a portion of the astrocyte activated

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35
Q

Maintenance of Synapse Homeostasis

A

Astrocytes influence synapse function by regulating homeostasis of the interstitial fluid within a synapse

via aquaporins and ion transporters that allow for pH change and ion level balances

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36
Q

Gliotransmitters at the tripartite synapse

A

ATP - Glia to glia - Metabotropic receptor - decreases glial cell Ca levels

Glutamate - Neurons and glia - N: ionotropic receptors (AMPAR’s and NMDAR’s); Astro: Metabotropic receptors - Enhances NT release, enhances EPSPS, can increase or decrease Ca levels

D-serine - Postsynaptic neuron - ionotropic receptor (NMDAR) - enhance EPSPS

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37
Q

Functional Neuroimaging

A

Can measure neural activity directly by either electrical or magnetic changes produced in response to neural activation or
indirectly by measuring cerebral blood flow, blood oxygen levels, or oxygen or glucose consumption

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38
Q

Measuring electrical and magnetic signals

A

EEG: electrical potentials of a large population are measured by electrodes. Overall brain activity. Sleep and wake have been measured. Can compare to other electroencephalogram to detect abnormality. Good temporal quality but poor spatial quality

MEG: measures neural activity by capturing magnetic fields produced by active neurons. Similar temporal resolution but better spatial spatial resolution

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39
Q

Metabolic signals

A

indirect measurement of neural activity
Positron Emission Tomography: measures local changes in cerebral blood flow. Radioactive tracer injected into the blood stream. First administered at rest and then at experiment. high levels of gamma levels indicate high levels of blood flow and increased function

fMRI: Relies on the magnetic properties of hemoglobin. Measures the ratio of oxygenated to deoxygenated HG in the blood (Blood oxygen level-dependent effect). With increased activity the BOLD will increase. Better than PET

Photoacoustic Imaging: Used for static imaging and Functional imaging. Pulsed laser is shot into tissue to create pressure waves. Ultrasound transducer outside of the tissue detects waves and generates images. Used to measure BO saturation, blood flow, or temperature. Used with a tracer or probe. High spatial resolution and lower cost than PET

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40
Q

Cognitive network characteristics

A

Appear early during embryonic development
Support all cognitive function
Constantly modulate neural activity and are referred to as “brain state modulatory controls”. Regulate widespread information flow throughout the brain.
Organized in a hierarchy
Exhibit functional stability in the face of local network damage
Are created and altered by synaptic plasticity processes
Consist of many long reaching axonal branches
Categorized by NT utilized

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41
Q

Biogenic amine transmitter

A

Regulate various brain functions and are implicated in a variety of biological roles ranging from homeostatic maintenance to cognitive processes
Defects in networks using these NT is usually indicative of phsyciatric disorders

Dopamine, NE/E, histamine, serotonin
acetylcholine important in PNS and CNS for many functions

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42
Q

General features of Single-source divergent networks

A

Utilize a unique NT (all small molecule NT and Ca release dependent)
Source of neurons that release a single NT is contained in a nuclei
Location of nuclei: Brainstem, hypothalamus, and basal forebrain
Network neurons have unmyelinated neurons that are highly arborized.
All 5 networks are interconnected and work together to control overall brainstate.

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43
Q

Neural network local circuits

A

Connect the 5 single-source systems
Contain excitatory and inhibitory synapses
Serial, Parallel and reciprocal processing connections

44
Q

Overall brain state control

A

Accomplished by the 5 single source divergent networks
interact with each other and also send processes to other regions of the brain such as the thalamus and cortical regions

consciousness, sleep and wakefulness, attention, emotions, learning and memory processes, and the monitoring of overall physiologic state of the body

45
Q

5 systems affects on spinal cord, thalamus, cortex

A

Affects all regions of the spinal cord
Has an indirect effect on the thalamus via thalamic reticular nuclei, intralaminar nuclei
Affects all regions of the cortex

46
Q

Non-directed synapses

A

unmyelinated axons of the neurons of the 5 systems release NT through these
NT molecules are released in response to intracellular Ca from varicosities of the axons.
NT molecules can then diffuse freely in many directions

Large number of cells are affected
Long duration of modulatory effects

47
Q

Ascending reticular activating system

A

Includes several circuites which originiate from the brainstem and ascend through the intralaminar thalamic nuclei and thalamic reticular nucleus to the cerebral cortex
All five of the single source divergent networks communicate via the axonal projections in of the thalamic ARAS
Produces state of conciousness

48
Q

Thalamic ARAS Functional Nuclear Relay Regions

A

Intralaminar thalamic nuclei (ILn) and the thalamic reticular nucleus (TRn)

49
Q

Norepinepherine/Noradrenaline (NE/NA) System

A

Norepinephrine is created in the locus coeruleus
Actiosn can be either inhibitory and excitatory
Lc sends projections to the cerebrum, hippocampus, cerebellum, and hypothalamus. Also limbic structures like the amygdala.

50
Q

Norepinepherine/Noradrenaline (NE/NA) System Function

A 
Attention and arousal
Fight or flight
Negative emotion processing
Regulaton of deep sleep 
Support learning and memory
Aid in cognitive performance
51
Q

Histamine system

A

Found in neurons in the hypothalamus
Send out axonal projections to regions of the spinal cord
Tubermamillary nucleus is th esole source in the CNS
Only excitatory
Targets include:
Brainstem, spinal cord, hippocampus, thalamus, cerebellum, cerebrum

52
Q

Functions of the histamine system

A

Mediation of arousal and attentionModulation of body energy stores
Control of circadian rhythms
Support memory and learning

53
Q

Serotonin system

A

Produced mainly in several groups of neurons known collectively as the Raphe nuclei. found in region from pons to the midbrain
Inhibitory/excitatory
Cerebellum, brainstem, spinal cord, thalamus, hypothalamus, cerebrum

54
Q

Functions of serotonin system

A 
Mediation of attention and arousal 
Suppresion of behavior
Modulation of negative emotions
Support learning and memory
Control of deep sleep
55
Q

Acetylcholine system

A

eight distinct nuclei (Nucleus basalis of meynert and pentopeduncular nucleus)
The NB is located below the anterior part of the thalamus and lenticular nucleus within the anterior perforated substance. The PPN is located in the midbrain adjacent to the substantia nigra

Excitatory only actionat NMJ but both in the brain

thalamus, hypothalamus, hippocampus, cerebrum

56
Q

Functions of acetylcholine system

A

Mediate attention and arousal
Support learning and memory
Control REM sleep

57
Q

Dopamine system

A

Specifically in nuclei of the ventral tegmental area (VTA) and of the substantia nigra (SN). MIDBRAIN
Target neurons of the nucleus accumbens of the basal forebrain

58
Q

Functions of dopamine system include

A

positive reward network and motivation
positive emotion and mood
Supports learning and memory
Mediates attention and arousal

59
Q

Positive reward network

A

Dopamine plays a role in reward, reinforcement, and motivation
Increased activation of dopamine system leads to the production of positive feelings. The more often these pathways are stimulated the greater the drive for whatever pathway caused the surge becomes (caution)

60
Q

Dopamine activation and drugs

A

Cocaine and amphetamine stimulate system by blocking reuptake and transport of dopamine away from synaptic cleft. This results in a net increase in the dopamine in the cleft and activates dopaminergic system
methamphetamine and amphetamine also stimulate Ca dependent release of DA into the synaptic cleft
Opium and heroin achieve their effects via disinhibition: they inhibit GABA-ergic inhibitory interneurons and increase firing of the DA neurons in the VTA. THC is also able to inhibit interneurons that inhibit VTA neurons

Nicotine binds a glutamate receptor on glutamergic neurons that excite VTA neurons. Glutamate then binds to receptors on VTA neurons and releases dopamine

61
Q

Sleep-Wake cycle

A

Awake stage: Individual is conscious and all 5 networks are active

Non-REM sleep

REM Sleep

62
Q

Non-REM sleep

A

Stages 1-4 are non-REM sleepTriggered by the release of adonsine from astrocytes
Activity of NA neurons in the locus coerulous and the 5-HT neurons of the raphe nuclei

Stages 1-2: light sleep
Stage 3: moderate deep sleep
Stage 4: Deepest level of sleep (Slow-wave sleep)

63
Q

REM Sleep

A

Follows the 4 stages of REM sleep
Vivid hallucinations
Activation of Cholinergic neurons in the pons initiates effects of REM sleep
Increased activity of the GABergic neurons in the reticular formation (pons) send projections to inhibitory neurons that synapse on LMN and produce the physical paralysis of sleep

EEG recordings taken during REM sleep are similar to those of the awake state

An individual will cycle through 4 periods of REM sleep per sleep wake cycle

64
Q

which of the 5 systems are active with wakefulness states

A

Awake: ALL 5
Non-REM sleep: Norepinephrine, serotonin
REM sleep: Acetylcholine

65
Q

Importance of REM sleep

A

During development REM sleep occupies a greaterpercentage of sleep-wake cycle than in adults

REM rebound: REM hours will catch up with lost time after sleep deprivation

With REM deprivation performance on cognitive tasks were decreased

Important for memory consildation:
Greater % of REM sleep with periods of intense mental activity
REM brain wave patterns are repeated for tasks learned before REM sleep
Memory deficits follow REM deprivation

66
Q

Importance of Non-REM sleep

A

Conservation of energy and restoration of the mind
No effect on body (with deprivation can still exercise but there are marked cognitive deficits)

Sleep induction theory
Release of NT uses up stores of glycogen and with energy source depletion glial cells release adenosine
Receptors in the cerebral cortex, thalamus, and brainstem bind adenosine that promotes the induction of Non-REM sleep
Periods of non-REM sleep replenish glycogen stores of the glial cells

67
Q

Sleep and removal of waste in brain

A

As one sleeps the cells of the brain contract allowing for CSF to flow through and depost metabolic waste into the vasculature
Disruption of waste removal is implicated in neurological disorders such as Alzheimer’s and formation of amyloid beta plaque’s

68
Q

Glymphatic system

A

Form of lymphatic system used by CNS. Significantly enhanced during sleep and inhibited while awake
rapid fluid exchange between CSF and interstitial fluid facilitated by aquaporins found on the endfeet of astrocytes which completely surround the vasculature
Fluid moves into the brain parenchymaand towards the space surrounding large veins
Leaves the brain as it is drained into the central lymphatic system

69
Q

Driving forces of glymphatic transport of CSF

A

Constant production of CSF pushes CSF to flow into the subarachnoid space
Respiration can aid the movement of CSF through the ventricular system
Smooth muscle surrounding the pial and penetrating arteries cause pulsation that can drive fluid movement

70
Q

Positive emotions

A

Modulated through dopamine
Dopaminergic neurons of the Ventral tegmental area in the brainstem send projections to the basal forebrain (nucleus accumbens)
ACtivates nucleus accumbens and consequently activity of the amygdala is inhibited

VTA also sends projections to medial prefrontal cortex which aids in the processes of working memory with positive emotion. Anterior and posterior areas of the cingulate gyrus which is involved in attention. Insula which aids in the modulation of all emotions

71
Q

Negative emotions

A

Processed through the NE and the serotonin systems
Serotinergic neurons of the raphe nuclei and the noradrenergic neurons of the locus coeruleus along with neurons within the periaqueductal region send excitatory neurons to the amygdala. Acivation of the amygdala suppresses the activity of the nucleus accumbens

The Lc, nR, and PAR activate the orbital prefrontal cortex for working memory with negative emotion, anterior cingulate gyrus which focuses attention, and the insula

72
Q

Cortical column properties

A

Functional units of information processing in all cortical regions (sensory and motor input and cognitive function)
Contains 100 neurons
Typically contains 6 distinct histological layers
Neurons within a column respond to similar stimuli. Columns can be linked together to form larger groupings that reach across the cortex and subcortical area, particularly the thalamus

73
Q

Cortical layers 1-3

A

Supragranular layers: upper three layers closest to the cortical surface
L1: molecular layer - synaptic field comprised of dendrite and axonal branches of other neurons
L2: external granular layer - pyramidal cells and interneurons
L3: external pyramidal layer - contains pyramidal cells

All of these layer send projections to layers of other cortical columns
Reciprocal connections with 1-3 layers. Nonreciprocal connections with 5-6

74
Q

Cortical layer 4

A

Divides cortical column into supra/infragranular regions
Contains mostly stellate cells
Input from thalamus
Input to other layers within the same column

75
Q

Cortical layer 5-6

A

Infragranular layers
Input from supragranular layers of adjacent columns

L5: large pyramidal cells, interneurons and Betz cells in the primary moto cortex
L6:Contains fusiform neurons, pyramidal cells, and interneurons

Does not send projections back to adjacent columns
Sends projections to thalamus, straitum, brainstem, and spinal cord

76
Q

Cortical columns and the thalamus

A

Thalamus receives input from all regions of the brain
Works with the thalamus to create a feedback circuit (infragranular layers –> thalamus –> layer 4)
Information flow within the cerebral cortex is mediated by the action of the supragranular neurons while additional information from the internal and external environment is integrated by the thalamus to the 4th layer

77
Q

Processes of memory

A

Encoding: acquisition of information “learning”
Retention: storage of information
Retrieval: accessing stored information

78
Q

Temporal memory

A

3 classes
Short term memory: limited capacity that is limited over time
Working memory: similar to short term memory while using that information to plan and carry out action
Long-term memory: retention of unlimited information consolidated from short-term or working memory, unlimited time?

79
Q

Working memory

A

Involves keeping relevant information accessible for short periods of time while a task is being completed

Operates in real-time
limited capacity: once thought to be 7 items but now only 4
Goal-directed action
distinct functions

80
Q

Distinct functions of working memory

A

planning: developing and executing a strategy
selection and suppression: Identifyign relevant components of the task and focusing on that task
Task monitoring: keeping relevant information online and updating this info as the next step in the task is determined.

81
Q

Brain regions involved in working memory

A

Requires activation of areas of brainstem utilized by teh 5 SSDNs which send projections to the thalamus Ascending Reticular Activating System (interlaminar nucleus and thalamic reticular nucleus) and the mediodorsal nucleus of the thalamus
The thalamic nuclei then communicate with regions of the prefrontal cortex

82
Q

Prefrontal cortex and memory

A

Lateral PFC: RIGHT lpfc processes perceptual data and the LEFT lpfc processes symbolic data (language and semantic information

Medial PFC: processes positive emotion and positive emotional memory

Orbital PFC: processes negative emotion and negative emotional memory

83
Q

Brain regions involved in attention

A

Five SSDNs

Tectum: Controls auditory and visual responses
Inferior colliculi - auditory stimulus
Superior collliculi - visual stimulus

Thalamic ARAS (Iln, TRn) and pulvinar nucleus of the thalamus: act as a relay station between the tectum and the 5 SSDNs and the cortex

Cingulate gyrus: Helps to maintain state of alertness

RLPFC: Working memory related to perceptual processing

Right Superior Parietal Lobe: Controls shift in attention Including shifts of attention between different spatial locations

84
Q

Long Term memory major divisions

A

Declarative memory

Non-declarative memory

85
Q

Declarative memory

A

Knowledge that we have concious access to and is known as explicit memory

Semantic memory: Knowledge about the world
Episodic memory: Knowledge about own life

86
Q

Non declarative memory

A

Encompasses several forms of knowledge and is revealed when an individual performs a task that does not require intentional recollection

Procedural memory: learning of motor and cognitive skills
Priming: Memory that involves a change in response to a stimulus as a result of previous exposure to stimulus
Classical conditioning: Pavlov! A conditioned stimulus (Bell) is paired with an unconditioned stimulus (Salivating as a result of food) which results in an evoked response to conditioned stimulus (salivating at bell)
Nonassociative learning: requires simple forms of learning like HABITUATION (decreased response with overload of stimulus) and SENSITIZATION (Increased response with stimulus overload)

87
Q

Patient HM and memory loss

A

Bilateral medial temporal lobectomy
Anterograde amnesia
cannot recall skills learned after surgery but CAN access non-declarative memory and working memory (small win!)

88
Q

Lessons from HM

A

Functioning of the medial temporal lobe (MTL) was necessary for memory

The processes underlying storage of short-term and long-term memory are different

Two distinct categories of long-term memory exists: explicit (declarative) and implicit(nondeclarative)

89
Q

Rats, hippocampus and memory test

A

Goal: find hidden platform in opaque water
Rats get better at the task with subsequent exposure
Rats with hippocampal lesions prior to learning are unable to improve
Rats with hippocampal lesions after learning are able to perform at the same level

HIPPOCAMPUS is needed for FORMATION but not for storage or retrieval

90
Q

Medial Temporal lobe

A

Binds and keeps track of all relevant circuits used in working memory
Uses NT glutamate
Directs the consolidation of memory into long term storage by maintaining linking of all relevant networks so that they can be activated as a group later for recall

91
Q

Major memory structures within MTL

A

Hippocampus: Mediates spatial memory (parahippocampal gyrus)

Amygdala: modulates the encoding and storageof hippocampal-dependent memories

Rhinal Cortex: Another card

92
Q

Rhinal Cortex

A

Perirhinal cortex: Controls object recognition

Entorhinal cortex: Interface between neocortex and hippocampus. Important role in formation and consolidation of episodic and spatial memories. Sends projections to the dentate nucleus (hippocampal formation) that also helps with episodic memory formation

93
Q

Two forms of Long Term Potentiation

A

Early LTP: synpatic changes for several minutes to 3 hours. Now new proteins were formed or change in synaptic morphology
Late LTP: 3-24 hours. New proteins within neuron, synaptic morphology changes observed.

94
Q

Associativity

A

Induction of LTP by the stimulation of two sets of synapses that are activated concurrently

Thought to strengthen the connections between relevant information

95
Q

Specificity

A

Phenomenon in which LTP is elicited at one set of
synapses on a postsynaptic cell, whereas adjacent synapses that were not activated do not exhibit LTP-like changes. Sight and smell of a rose will activate BOTH pathways even if only one is presented.

96
Q

Nondeclarative memory characteristics

A

Memory without recall or awareness
Experience alters behavioral performance unconsciously

Evidence for implicit memories can be found in preferences, habits, and dispositions that are inaccessible to conscious recall (both during and after acquisition)

Implicit memory is not dependent on the MTL

Can be categorized into four subtypes:
Procedural habit or skill memory
Priming
Classical conditioning
Non-associative
97
Q

Procedural/Habit or Skill Memory

A

Learning of a variety of motor and cognitive skills. Repeated rehearsal improves skill performance. Context specific
Damage to Basal Ganglia shows severe deficits

98
Q

Priming

A

Change in response to a stimuli or the ability to recognize a stimulus as the result of prior exposure to that stimulus. A single activation of a network that readies it for learning occurs in the neocortex.

Previous exposure makes it easier to activate the same pathway

Even a single exposure to a cognitive item can greatly increase retesting

99
Q

Classical conditioning responses

A

Skeletal muscle responses: motor control controlled by cerebellum
Emotional responses: Controlled by the nAC, amygdala, orbital/medial prefrontal cortex

100
Q

Sensitization

A

Cues teh CNS about novel stimuli that may be essential for survival. Increased response to novel or harmful stimuli.
In sensory motor reflex pathways
STP and enhanced release of NT

101
Q

Habituation

A

Ignore stimuli that have lost their meaining or novelty. Ignore begnin stimuli.
In sensory motor reflex pathways
STD

102
Q

Exposure to noxious stimuli

A

after exposure to noxious stimuli all responses are heightened. If noxious is paired with a benign stimuli the benign will also have increased response

103
Q

Intuition and emotion

A

Implicit memory processes involving emotion and “intuition”
Actually play a crucial role in an individual’s ability to make decisions. Non-conscious emotional signals may factor into decision-making before conscious processes do. These processes appear to be mediated by the ventro-medial prefrontal cortex (VM PFC).

104
Q

Ventro-Medial Prefrontal Cortex

A

Responsible for the storage of past rewards and punishments

Triggers non-concious emotional responses

105
Q

Ventro-Medial Prefrontal Cortex Lesions

A

Display little emotion in social situations and no empathy towards others
Perform well on IQ and memory tests but exhibit poor decision making ability
Have intact factual knowledge but emotional memories are absent
Exhibit dissociation of socially appropriate goal-directed (reward) behavior and willful behavioral action

PET scans of violent criminals and those exhibiting sociopathology showed abnormally low regional cerebral blood flow (rCBF) in all ventro-medial prefrontal cortical areas

Neurophysiology (3 decks)

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