Behavioral Neuro Test 2 Flashcards
neuroscience approach behaviour methods
- stereotaxis surgery
- invasive electrophysiology
- immediate early gene (IEG) expression and tract tracing
stereotaxis surgery methods (3)
permanent lesions, electrode impanted in rat brain. and cannulation
bregma and lambda
bregma is an area on top of brain used as reference pooint. it is area on top of skull where two sutres (seams of in skull) intersect. lambda is another one of those reference points
stereotaxtic atlas
map of where a landmark is in brain.
IEG expression and tract tracing (3 types)
- double labelling
- optogenetics
- DREADDS
behavioural approach in methods for neuro
- open field test
- elevated plus maze
- radial arm maze
- morris water maze
- conditioned defensive burying
- conditioned taste aversion
intracellular unit recording
intracellular microelectrode records the membrane potential from a single neuron
extracellular unit recording
tip of microelectrode is in extracellular fluid next to neuron. records electrical disturbance each time a single neuron fires an action potential
multiple unit recording
electrode is larger than microelectrode- so it records the action potential of many nearby neurons; these are summed together
invasive EEG recording
a large implanted elctrode reocrds general changes in electrical brain activity; not specific to action potentials
in FG example, what were CS and US?
conditioned stumulus= light
unconditioned stimulus= food
why do we want to wait when using IEG expression and double labelling
wait 90 minutes because the protein (fos) takes about 90 minutes to be expressed
double labelled cells
cells that label for BOTH fg and fas
why do double labelled cells mater?
they are activated by a behavioural event and anatomically project from one brain region of interest to another.
this allows us to find behaviral functions of anatomical projections
fos vs fg
FG is a retrograde tracer and fos is a natural protein, IEG expression. Fos is present when neurons were fired/active.
direct method of labelling
flouresence
indirect method to label
antibodies. this is often the preferred method because there is more amplication
goat and rabbit antibody example (this is indirect method)
- an antigen is injected into a rabbit.
- the rabbit produces an antibody
- that antibody from the rabbit is injected into a goat
- the goat produces that antibody as well
optogenetics defintion
manipulating neural activity with light. this is done by using light sensitive algae and inserting it into the brain. light can depolarize or hyperpolarize channels.
opsin
a highly light sensitive ion channel. how? put genetic code to making opsin into a virus. virus is modified to tell cells to produce opsin. infuse virus into brain
2 types of opsin
channelrholdopsin and halorhodopsin
channelrholdopsin
opsin type- blue light depolarizes neuron because Na+ enters the cell. blue light causes Na+ to enter the cell
halorhodopsin
stimulated by yellow light. yellow light opens Cl- channels and hyperpolarizes cells
DREADDS
- **Engineered Receptors: **DREADDs are specially designed G protein-coupled receptors (GPCRs). Unlike natural receptors, DREADDs don’t respond to their usual, or endogenous, signaling molecules. For instance, if a DREADD receptor is derived from a receptor for acetylcholine (ACh), it will not be activated by ACh. These are specially engineered proteins that scientists put into certain brain cells.
- Designer Drug Activation: Scientists create a special drug that only activates these designer receptors. DREADDs are activated only by a unique synthetic drug, or designer drug, that’s created specifically for this purpose. This drug doesn’t interact with any other receptors in the body, so it won’t interfere with other brain or bodily functions.
- **Precise Control: **Because this synthetic drug only activates the engineered DREADD receptors, scientists can precisely control the activity of targeted neurons. This enables very specific manipulation of brain signaling without affecting other cells.
- Purpose: By turning specific brain cells on or off, researchers can study what those cells do, which helps in understanding behaviors, emotions, and even brain disorders. DREADDs are valuable in neuroscience research, helping to create precise effects without affecting the whole brain.
optogenetics and DREADDS similarites
both use viral vectors (a modified virus that delivers genetic material into cells) to get proteins expressed in cell membrane of neurons
optogenetics proteins
opsins
DREADS proteins
they make up the designer G=protein coupled receptor
neuro activation or inactivation is control by what (in optogenetics vs DREADDS)
optogenetics- light
DREADS- chemicals/drugs
pros of optogenetics
- can modify neural activity (in ms)
- can time back neuronal exeitation or inhibition to a specific behaviour
cons of optogenetics
- animal has fiber optic cable coming out of head
- limit movement + cause confounders (although you can use control groups to help w this)
pros of DREADDS
- designer drug can be administered peripherally (less invasive)
Pro and con (depending how you look at it) of DREADDS
- stimulate of inhibit neural activity in longer lasting fashion (minutes or hours) – this can be a pro when behaviour task involved ongoing behavior
anxiolytic drug
anxiety reducing drug
Case of Genie
- she was 13 and weighed around 60lbs and couldn’t chew food.
- she had been beaten, starved, etc. since being 20 months old.
- she never truly returned to normal even after special care. she couldn’t chew and had language issues.
why do we want to learn case studies(feral children)
to learn development. things that can result from these studies:
* motor behaviour issues, can’t chew, easily terrified
* inappropriate reactions (i.e silent tantrums)
postnatal brain growth is a result of…
- synaptogenesis
- myelination
- increased dendritic branching
- overproduction of synapses (could be a reason for more plasticity in young brains)
- normal regressive changes
synaptogenesis(+ when and where)
the process of forming connections(synapses) between neurons in the nervous system
* primary visual and auditory corticies- synaptogenesis spurt at 4 months of age. maximum density is at 7-8 months and then it decreases
* profrontal cortex- sunaptogenesis proceeds at relatively steady rate. maximum density occurs at 2 years
myelination (development)
the process where nerve fibers in the central and peripheral nervous system are wrapped in a protective layer called the myelin sheath
* starts in sensory areas (first few months of life) and then motor areas
* myelination of prefrontal cortex continues into young adulthood.
increased dendritic branching
dendritic branching in cortex progresses from deeper to more superficial layers
The more branching a dendrite has, the more connections it can form, allowing for richer and more complex neural networks.
Dendrites branch from deep to superficial to increase their surface area, which allows them to receive inputs from thousands of other cells or the environment.
normal regressive changes in brain development
- synaptic density scales back after maximum is reached
- cortical thinning of gray matter
- dendritic pruning
critical or sensitive learning periods
time period when sensitive to inputes leading to development changes
conrad lorenz + study thing with ducks
- human ‘mother’ to duckings
- developmental recognition of caretaker
- CRITIAL period
critical period
essential for experiences to occur in this window to impact development
sensitive period
experience can have large impact in development on this time period. outside, it can still have weak effects
johnson and newport (1989)
- subjects- 46 native chinese or korean learners of english (in US for at least 3 years). Had different arrival times
- method: grammatical judgement test
- results: accuracy correlated with age for anyone who arrived to US before puberty. those who arrived after puberty was not correlated with accuracy
language development: infants (4 months)
can distinguish all human speech phonemes
language development: 6 months
show preference for native language phonemes
language development: 1 year
no longer respond to phnemes of non-native language
language development: 4-6 years
decline in professiency can occur
language development: 10 years
can learn to speak native language without an accent
visual development critical period- where is V1 primary
- V1 primary visual cortex located in the occipital lobe
visual development critical period- occular dominance collumns
eye preference. like right handed but for eye. activated more by input from one eye or the other
experiment for occular dominance collumns
researchers might temporarily close one eye during an animal’s early development and then observe changes in V1 neurons
Procedure: By sewing one eye shut (or using a temporary blindfold) during a critical period in early life, researchers limit input to the visual cortex from that eye.
Effect on Neurons: Without input from the closed eye, the visual cortex’s response to that eye’s signals weakens over time. Meanwhile, neurons in V1 that receive input from the open eye become more active and start to take over. This happens because the brain cells from the open eye essentially “compete” for space and become stronger in response to the increased activity.
Competitive Reorganization: Over time, the columns in V1 change. The columns related to the open eye grow wider and more robust, while those for the closed eye shrink. This restructuring reorganizes the system, increasing dominance of the open eye in the brain’s visual processing.
monocular deprivation
The practice of covering one eye, which can cause a shift in ocular dominance.
neurons and synapses not activated by experience
they usually do not survive. use it or lose it
humans are uniquely slow in neurodevelopment. why?
allows more time for fine-tuning
early visual deprivation
- When visual input is reduced during critical developmental stages, neurons in V1 form fewer synapses and dendritic spines (the tiny protrusions on dendrites where synapses are formed). With less stimulation, the brain doesn’t develop the usual rich network of connections necessary for processing complex visual information.
- deficits in depth and pattern visions as adults
enriched environment for early visual experience
- thicker cortexes
- greater dendritic development; more dendritic spines
- more synapses per neuron
effect of experience on topographic sensory cortex maps
- Cross-Modal Rewiring: In these experiments, scientists rerouted visual input to the auditory cortex in young animals, such as baby ferrets. This means that instead of only hearing, the auditory cortex received signals that would normally go to the visual cortex.
- Auditory Cortex “Sees”: Remarkably, the rewired auditory cortex adapted to process these visual signals, essentially “seeing” through sound-processing areas. The cortex reorganized itself to respond to visual information, demonstrating that sensory areas aren’t rigidly fixed for one type of input but can adapt based on early experiences.
- **Critical Period: **This plasticity works best in early development, when the brain is especially adaptable. During this time, sensory cortices can reorganize themselves in response to new types of input, showing just how flexible the brain can be in its wiring.
how does neural activity influence CAMS
* CAMs– proteins located on the surface of a cell membrane that facilitate the binding of one cell to another or to the extracellular matrix, essentially allowing cells to “stick” together and forming tissues through a process called cell adhesion
*** Regulation of CAM Expression: **Neural activity can influence which genes are turned on or off, and this gene expression guides the production of CAMs. By regulating CAM levels, neural activity helps direct cell adhesion processes, shaping how neurons connect to each other and to surrounding structures, which is essential for organizing tissues.
* Guiding Regenerating Axons: In the Peripheral Nervous System (PNS), CAMs are especially important because they mark pathways along which regenerating axons can grow after injury. Increased CAM expression provides a “road map” for axons, helping them find their correct paths as they repair and reconnect.
Neurotrophin Release: CAMs also help trigger the release of neurotrophins, molecules that promote neuron survival, growth, and the formation of synapses. Neurotrophins help refine neural circuits, promoting the development of strong, functional networks.
**Activity-Dependent Development: **Some neural circuits are spontaneously active even in early development, and this activity is critical for normal brain growth. These spontaneous activity patterns stimulate the production and organization of CAMs, supporting proper connectivity in the developing nervous system.
development of prefrontal cortex
believed to underlie age related changes in cognitive function. no single theory explains the function of this area. prefrontal cortex is the slowest to develop
Diamond + Goldman-Rakic
- 7- to 12-month-old human infants tend to perseverate, meaning they repeatedly make the same response even when it is no longer appropriate. This behavior is often studied using the A-not-B task, where a toy is hidden in one location (A), then moved to a different location (B). Infants under a certain age often continue reaching toward location A even after seeing it moved to B
- infant (but not adult) rhesus monkeys also perseverate
- However, studies have found that adult rhesus monkeys with bilateral lesions to the dorsolateral prefrontal cortex do show perseverative behaviors, similar to those seen in human infants and infant monkeys.
gray matter peaks when
adolesence
white matter - age
continually increases with age. axon connectivity continues to develop
frontal lobe- age
develops later than subcortical emotion centers- 25ish years
regeneration
damaged neuron regrows
reorganization
reorganization of connectivity
recovery
recovery of function
anterograde degeneration
anterograde refers to degeneration that moves forward, from the injury site toward the synaptic terminals at the axon’s end.
The part of the axon beyond the injury, known as the distal segment, is cut off from the cell body, which serves as the neuron’s metabolic center. Without access to essential nutrients and metabolic support from the cell body, the distal segment cannot maintain itself.
Within a few days of the injury, the distal segment begins to swell and break apart as it undergoes structural breakdown. This process leads to the eventual disintegration of the distal segment, which may also result in the degeneration of any synaptic connections it maintained.
retrograde degeneration
In this context, retrograde means moving backward toward the neuron’s cell body
progresses slowly;
he segment of the axon that remains attached to the cell body, known as the proximal segment, can begin to degenerate if it is not able to re-establish functional connections.
If the neuron’s axon can regenerate and make a new synaptic contact, it may survive.
apoptosis
form of active, programmed cell death that cells undergo as a natural and regulated part of growth, development, and tissue maintenance. cell death
necrosis
Necrosis is a type of passive cell death that occurs as a result of injury or trauma to cells and tissues.
Neural regeneration
In mammals and other higher vertebrates, neural regeneration does not proceed successfully, especially as they reach maturity. This limited capacity for regeneration is due to several factors:
**Loss of Regenerative Capacity with Maturity: ** Young neurons in developing mammals have some ability to regenerate axons accurately. However, as the nervous system matures, this capacity for precise axonal growth diminishes.
Limited Regeneration in the CNS: In the central nervous system (CNS)—which includes the brain and spinal cord—neuronal regeneration is virtually nonexistent in adult mammals.
In PNS, regeneration is possible but not likely.
Regeneration in the PNS (ways cell could regrow)
- if original schwann cell cyelin sheath is intact, regenerating axons may grow through them to their original targets
- if nerves is severed and the ends are separated, they may grow into incorrect sheaths
- if ends are widely separated, no meaning regeneration will occur
regeneration in CNS
regeneration does not happen in CNS.
- Interestingly, CNS neurons can regenerate if transplanted into the PNS, demonstrating that their intrinsic regenerative potential is not entirely lost. The PNS environment provides a more supportive context due to the presence of Schwann cells
- In contrast, PNS neurons won’t regenerate when transplanted into the CNS. Even though PNS neurons are capable of regeneration, the inhibitory factors and lack of supportive guidance from the CNS environment prevent axonal regrowth.
schwann cells
promote regeneration. release neurotropic factors that stimulate growth. produce CAMs that provide pathways.
oligondendroglia
actively inhibit regeneration. located in CNS.
reorganization of primary sensory and motor systems
has been observed in lab animals as a result of damage to peripheral nerves and/or damage to primary cortical areas
when you leasion small part of retina and remove the other
When a small part of the retina is lesioned and the remaining part is removed, V1 neurons can undergo remapping. This means that neurons in V1 that originally responded to stimuli from a particular area of the retina begin to respond to stimuli from adjacent areas. This remapping happens quickly, within minutes, as the brain adapts to the loss of sensory input from the lesioned region.
(boundary increased by over 1 cm which is a lot in the brain)
monkey reorganization somatosensory cortex
face area expanded into arm area following cut of arm sensory neurons
cortical plasticity
- ‘use it or lose it’
- cortical areas are constantly competing for empty space
- as you use areas, their representation gets bigger
cortical reorganization
following brain damage in humans. brain imaging studies indicate that there is continuous compettiion for cortical space by functional circuits. i.e. auditory and somatosensory input may be processed in formerly visual areas of brain of blind individuals
Gap Junctions
Some communication between cells goes through gap junctions
Gap junctions are sometimes referred to as “electrical synapses”
They connect the cytoplasm of two adjacent cells, and allow electrical signals and small molecules to pass between them
Gap junctions transmit signals more rapidly than chemical synapses
Agonist
Drug that facilitates the effects of a particular neurotransmitter
Antagonist
Drug that inhibits the effects of a particular neurotransmitter
Contrast X-rays
A conventional x ray doesn’t help with visualizing the brain, but contrast does because it injects a substance that absorbs x rays differently (either more or less) than other tissues in the area, into one area of brain.
Cerebral angiography
Puts radio opaque dye into cerebral artery to visualize the cerebral circulatory system.
Computed tomography (CT)
Computer-assisted x-ray procedure. Patient lies with head in center of a large cylinder. One side sends x ray and other side detects it. It rotes around the head and creates a CT scan of brain. Provides 3D visual representation.
Positron Emission Tomography (PET)
- FDG is injected into carotid artery (back of neck, goes to cerebral hemisphere). It is similar to glucose so it is taken rapidly by cells, but it cannot be metabolized so it accumulates until astrocytes break it doesn.
- PET scans are levels of the radioactivity on hirozonatal areas of brain (more active areas will be different colors)
Magnetic Resonance Imaging (MRI)
High resolution images. Constructed from radio frequency waves that hudrogem atoms emit when the are reacted with the powerful magnetic field. World because water contains hydrogen and different brain structures contain different amounts of water. Different amounts of water creates diferents waves emitted, so they will be different from different structures. VERY clear imagine and GREAT spatial resolution. (3D)
Functional Magnetic Resonance Imaging (fMRI)
- Produces images showing increased oxygenated blood flow to active aresa of brain. Active areas take up more oxygenated blood. Annnd oxygenated blood has different magnetic properties.
- BOLD signal- blood oxugen level dependednt signal. Indicatges where is more active or inactive during a test.
- Used to compare during experiments, so it is VERY important to measure a baseline condition so you can tell what is CHANGING!
- Poor temporal sesolution. Takes 2-3 seconds to measure BOLD signa;
Diffusion Tensor Imaging (DTI)
Type of MRI that Identifies paths that water diffuse at. Tracts are the routes of water diffusion, so this shows the major tracts of the brain.
Transcranial magnetic stimulation (TMS)
- The shortcoming of radioactive and magnetic imaging- can show correlation but not causation. This is where TMS was created
- Can turn off part of the brain by while looking at cognition and behaviour. Look to see if turning off a part of the brain impacts it. CAUSATION
Electroencephalography (EEG)
Recorded with large electrodes. Disk shaped things. The scap signal reflects sum of electrical events throughout the head. This includes action potentials, posynaptic potentials, and electrical signals from skin, blood, etc. Mainly used to for states of consciousness because electrical waves are different per state of consciousness. Waves decrease with distance, so amplitude of wave can indicate where it is coming from.
Event-related potentials (ERPs)
EEG waves that come from specific events that occur (i.e. if I was having a PANDAS flair-up).
Signal averaging-
taking an average of all all runs shows the impact of event on the EEG waves.
Magnetoencephalography
- Measure changes in magnetic fields on the surface of the scalp (produced by underlying neural activity)
- Advantages: spatial resolution and localize subcortical activity better than EEG
Electromyography (EMG): Muscle tension
Electrodes taped over muscle area. Tensing muscles can help indicate anxiety. Reflects number of muscle fibers contracting at a given time.
Electrooculography (EOG): Eye movement
There is a potential difference between front and back of eye (front=positive, back =negative). Change in electrical potential can be recorded because of this to measure movements.
Skin conductance: Distinguish between SCL vs. SCR
SCL : Measure of background level of skin conductance associated with the situation
SCR: Measure of changes in skin conductance that are associated with different experiences.
Heart rate (electrocardiogram (EKG)),
Electrical signal measured with each heart beat. Avg resting= 70BPM
blood pressure,
Measurement of peak pressure during heart contraction and measure of minimum during relaxation. Expressed as a ratio of peak(systole) over min (diastole)
blood volume (plethysmography)
Measure changes in blood volume in a part of body. More blood= response to psychological events. Wrap strain gauge around area to measure volume, or shine light through tissue and measure amount of light absorbed (more light absorbed when there is more blood)
Radio-frequency
technique to destroy tissue. Pass high frequency current through target tissue from tip of electrode. Heat destroyed tissue.
neurotoxic (selective chemical)
method to injure or kill areas of brain. These are substances that can cause selective lesions. Injecting neural poisons that have affinity for certain components of nervous system.
Aspiration
Lesion made in area that is accessible to the eyes and surgeon instruments. Tissue drawn out by suction of pipette. Underlying white matter is more resistant to suction so it is often undamaged and only area of interest is damaged.
sectioning (cutting)
Nerve or tract is cut. Purpose: to eliminate its electrical signals
Reversible
Temporarily cooling target structure or by injecting anesthetic. When it wears off, brain returns to normal.
Routes to administer drugs
- Fed
- Injected through stomach via tube in nose or mouth(intragastrical)
- Injected into abdomen(intraperitoneally), large muscle(intramuscular), fatty tissue(subcuntaneous), or large vein(intravenous).
Ibotenic or kainic acid
Ibotenic acid and kainic acid are neurotoxins that are commonly used in neuroscientific research to selectively damage certain types of neurons in specific regions of the brain.
Taken up by cell bodies at tip of cannula and destros these neurons.
Neurons with axons passing through are undisturbed
6-OHDA
Neurotoxin that is taken up by neurons that release norepinephrine or dopamine. Other neurons at site are undamaged.
2-DG
way to study brain activity. Place animal injected with radioactive 2-DG in test. 2-DG is similar to glucose, so neurons active during test absorb it at high rate byt don’t metabolize it. Animal is killed and brain is removed to look at levels of readioactivity, these appears as black spots on slides. Density can be color coded if needed.
Cerebral dialysis/microdialysis
Measure extracellular concentration of neurochemincals (concentration outside of neurons) in behvaing animals (does not require the animal to be killed). Implant fine tube into brain. Extracellular chemicals from the structure will be diffused into the tube and collected.
Immunocytochemistry
Locating neuroporteins in brain by labeling antibodies with dye or radioactive elements and then exposing isolated cells. Regions with dye or radioactive accumulation= location of neuroprotein targeted
In situ hybridization
Peptides and proteins are transcribed from nucleotide bases on mRNA. RNA strands with complementary base sequences to mRNA are obtained. The strands are lebeled with dye or radioactive element. Brain sleeves are exposed to labeled RNA strands and they bind to complementary mRNA strands to mark location of neurons that release parted neuroprotein
Gene knockouts
Way to create organisms that lack a particular gene. Shows that genes can work together and its not always one gene that dictates something.
Brainbow
Introduce GFP mutated for different colors into mice. Each neuron produced different amounts of three proteins and each protein had different color, so mixing the colors gave them unique colors and they can trace the pathways of these unique colors to their destinations.
GFP (green fluorescence protein)
GFP is protein that shows bright green fluorescence when exposed to blue light. Introducing GFP into brain can look at neurons.
Single test
Differentiate from patients with problems from structural damage to those with problems from functional changes. This was pretty unsuccessful because no single test could be developed that would be sensitive enough to look at all potential brain damage.
Standardized test battery
Using standardized batteries (sets of tests) instead of one single test. Only someone successful. Low score= brain damage- this worked well but it was hard to discriminate between neurological (nervous system) patients and psychiatric(mental health) patients
Customized test battery
Current? Goal is to characterize nature of psychological defieicts. Uses multiple tests to better understand general nature of symptoms. Then depending on results, tests specific to patient are chosen to dig deeper.
Repetition priming
Studying pattern. Shown words and asked to study them (not asked to remember them). Then later asked to complete words based on a few letters that were in it. Amnesic patients can complete the fragments but dont remember the word or seeing the lsit of words.
Paired-image subtraction technique
Interested in locating parts of brain that enable person to make word association. Take functional brain images during several different cognitive tasks. Tasks are designed so that only a single cognitive process differs between them. Then the brain activity that is eliminated on one is the one that is associated with the task.
Default mode network
There is activity in the brain even when we sit quietly and let our brains wander. Brain areas that are active during this but less active during cognitive or behavioural tasks default mode network.
Mean difference images
Averaging images to reduce noise found in PET and fMRI scans (i.e. if you are thinking about how you are hungry, a different area of the brain might be active but it will be reduced as it is part of the noise). This is averaged over all the participants so only part active in all or most participants is shown in the averaging.
open-field test-
measure fear by behavior in an open area
Colony-intruder-
aggression and defensive behaviors between dominant male rat and smaller male rat intruder). Dominant has hair erect, moved sideways, tries to bite, etc. intruder tries to protect themselves by rendering, pushing attacker away with forepaws, etc.
elevated plus maze-
Two arms have sides, tow do not. To measure defensiveness or anxiety- porportion of time rats spend in protected arms vs open. Less anxiety = more time in open arms
tests of sexual behavior
- Mounting- male tries to get female to engage in sexual behaviour
- Lordosis- position female takes to recieve sexual behaviour. Often takes multiple cycles or intromission (penetration) for sperm to eject.
- Measure:
times mounting is required for lordosis and intromission to occur
Number of intromission required for ejaculation
Interval between ejaculation and reinitiation of mounting
Pavlovian conditioning-
introduce CS(thing) with US(food) (that has a UR(salivation) and creates a CR(salivation to the random thing)
Operant conditioning
Rate at which voluntary response (lever press) is emitted based on reinforcement or punishment.
conditioned taste aversion (CTA)
Avoidance response that develops in response to food whose consumption is followed by illness. (not actually, but a drug is given to them that makes them sick after they eat)
radial arm maze
Spatial abilities or rodents. cup on arm has food. Then figure out if they revisit the arms that have food every day.
Morris water maze
Spatial skills. Find platform in water based on cues around the room. How many tries to get faster?
conditioned defensive burying
Aversive stimulus to see if they bury themselves in bedding. Antianxiety drugs will decrease burying.
phantom limb
face stimulation = amputated limb feelings. feeling in face and phantom limb. why? because face is next to limb in somatosensory cortex and the face area took over the arm area, but the brain remembers that a limb was there, so it gets confused.
release from inhibition
- when 2 nerves, B inhibits parts of A and vice versa
- if B is damaged, it no longer inhibits that portion of A, so now more area responds to touches of A
Collateral Sprouting
when neruon A is degenerated, neuron B can ‘spread’ to vacant spaces.
Recovery of function
- can have compensation strategies to make up for damage
- those with more cognitive reserve tend to recover better (i.e. intelligence)
- can see increased neurogenesis in adults following a change, but there is no evidence that cells can migrate to fill in the empty spaces
Types of rehabilitation therapy
- constraint- induced therapy
- cognitive exercise
- physical exercise
constraint induced therapy
there is competition for space in the brain, so you can constraint the good part so that bad part has a chance
Immunohistochemistry
Locating neuroporteins in brain by labeling antibodies with dye or radioactive elements and then exposing slices of the brain to the labeled antibodies. Regions with dye or radioactive accumulation= location of neuroprotein targeted. Looking at slice of tissue
kitten experiment
At two weeks of age kittens were randomly placed into one of two conditions for five hours a day: this was either a horizontal or a vertical environment. after 5 months they were put in normal environment.
All the kittens were extremely visually impaired;had no startle response when an object was thrust towards them. they guided themselves mainly by touch. After about 10 hours the kittens showed visual placing and some startled responses; they could also easily jump from a chair to the floor. never fully recovered, though, and couldn’t see things in opposite orientation than they were in.
neurogensis in adult mammals-rats (neurogenesis in olfactory bulbs and striatum vs hippocampus)
Neurogenesis in adults occurs in the hippocampus, striatum, and olfactory bulb (specifically the dentate gyrus). adult olfactory bulbs and striatal neurons become interneurons(intermediaries, processing and transmitting information between other neurons). hippocampus neurons become neurons that grow axons and form synapses on cells in other hippocampus areas.
Functional significance of neurogenesis
- brain repair
- plasticity
- cognitive function
- etc.
Epigenetics as it relates to the nature vs. nurture debate
Epigenetics refers to the study of changes in gene expression or cellular function that do not involve changes to the underlying DNA sequence. In other words, epigenetics is how environmental factors, lifestyle choices, and experiences can influence gene activity without altering the genetic code itself.
Epigenetics essentially bridges the gap between “nature” (genetics) and “nurture” (environment) by demonstrating how environmental factors can directly influence gene expression
Neural regeneration in CNS vs PNS (role of Schwann cells vs oligodendroglia)
In the nervous system, neural regeneration is significantly more prominent in the peripheral nervous system (PNS) compared to the central nervous system (CNS), primarily due to the contrasting roles of Schwann cells (found in the PNS) which actively promote regeneration, while oligodendrocytes (in the CNS) generally inhibit it
IEG expression
Immediate-early gene (IEG) expression is the process by which genes are rapidly and temporarily activated in response to a stimulus
Cannulation
Cannulation in the brain refers to the process of inserting a cannula (a thin, flexible tube) into specific regions of the brain to allow for the direct administration of substances (such as drugs or neurotransmitters), the collection of samples (such as cerebrospinal fluid or brain tissue), or the monitoring of brain activity.
Amino acids- neurotransmitters
small molecule neurotransmitter
glutamate
aspartate
glyche
GABA
Monamines
small molecule neurotransmitter
catecholamines
indolamines
catecholamines
dopamine
epinephrine
norepinehrine
indolamines
serotonin
unconventional neurotransmitters
small molecule neurotransmitter
solubale gases
endocannabinoids
soluble gases
nitric oxide
carbon monoxide
enocannabinoids
anandamide
neuropeptides
large molecule neurotransmitter
pituitary peptides
hypothalamic peptides
brain-gut peptides
opioid peptides
miscellaneous peptides
glutamate (effecgts)
excitatory- throughout brain
amino acid
glutamate subtypes
ionotropic
- AMPA
-NMDA
- Kainate
metabotripic
- mGluR
GABA (effects)
inhibitory
throughout brain
amino acid
GABA subtypes
ionotropic- GABAA
metabotripic- GABAB
acetylcholine (effects)
excitatory and inhibitory
ach subtypes(+ details)
nicotinic
- in PNS (mostly somatic )
- ionotripic
- 12 subunits: a2-a10 and b2-b4
muscarinic
- PNS (mostly autonomic)
- metabotropic
- 5 subtypes M1-M5
norepinephrine (effects)
excitatory and inhibitory
norepinephrine subtypes
only metabotripic
- Alpha1-2
- Beta 1-3
serotonin (effects)
excitatory and inhibitory
5-HT subtypes
7 different families, 14 known subtypes. all are metabotripic except 5-HT3
Dopamine (effects)
excitatory and inhibitory
dopamine subtypes
all metabotripic
D1 like
- D1 + D5
D2 like
- D2, D3, D4
