BIO SCI FINAL Flashcards
Cerebellum function
Motor coordination
Medulla oblongata function
Help a person breathe
Frontal lobe function
Executive function, functions to help you plan, organize, manage time, avoid or doing the wrong thing
What brain connection is disrupted in lobotomies?
Sever the connection between the entire frontal lobe of the thalamus (relay center for sensory system)
What is the behavioral effect of lobotomies?
Stops psychosis and children’s temper tantrums, stops the ability to connect with the world or make decisions
What is the Broca’s area?
Language production
What is the Wernicke’s area?
Language comprehension
What does SSRI do?
Allows serotonin to stay in the synapse and have its effects
What does SNRI do?
Allows serotonin and norepinephrine to stay in the synapse and have its effects
What does MAO-I do?
Involved in stopping the degradation of dopamine, serotonin and norepinephrine
What is the Monoamine hypothesis of depression?
Predicts that the “underlying pathophysiologic basis of depression is a depletion in the levels of serotonin, norepinephrine and/or dopamine in the central nervous system”
Axon function
Transmits electrical impulses (action potentials)
Axon terminal function
Typically where neurons send messages to other neurons
Cell body function
Contains genetic information, maintains the neuron’s structure and provides energy to drive activities
Dendrite function
Receives electrical information
Dendritic spines function
Typically where neurons receive messages from other neurons
What is the longest axon length in the human body?
Sciatic nerve, begins at your big toe and ends at the base of your spinal cord
What is exocytosis?
Cellular process in which substances exit via vesicles
What is endocytosis?
Cellular process in which substances enter via vesicles
What does botox do?
Inhibits vesicles from fusing to the plasma membrane by inhibiting proteins
What are dynamin mutants missing?
Missing a protein called dynamin which helps pinch vesicles from plasma membrane. Cannot split from plasma membrane, blocks endocytosis
Afferent in a neuron vs. Efferent in a neuron
Afferent: Information flows to the brain and spinal cord; sensory information
Efferent: Information flows from the brain and spinal cord; motor information
What is depolarization vs hyperpolarization?
Depolarization: positive voltage
Hyperpolarization: negative voltage
What are the sequential steps in an action potential?
-Step 1: Na+ channels open
Depolarize membrane potential away from the resting potential toward equilibrium potential for Na+
-During an action potential, the opening and closing of V-gated K+ and Na+ channels are well timed
-Step 2: K+ channels open
Hyperpolarization of the membrane potential towards equilibrium potential for potassium
-Step 3: After a delay Na+ channels inactivate, helping K+ channels to hyperpolarize membrane potential
What is membrane potential and the determinants?
The difference in electrical charges inside and outside a cell creates a voltage difference
Determinants: difference in ion concentration causes a voltage difference
What drug affects the action potential?
TTX blocks action potential within a neuron
How can energy and matter not be created or destroyed but can be changed from one form to another?
Directly reflected in the way neurons function, where chemical energy from glucose is converted into electrical signals (action potentials) that propagate through the neural network, ultimately driving thoughts, behaviors, and bodily functions
What are the counter arguments that propose that monoamine hypothesis of depression is wrong?
Unsuccessful antidepressant does not raise monoamine levels
Some people with depression do not have decreased levels of monoamines
Lesioning monoaminergic systems does not always induce or worsen depression
What are the two key components of the mesolimbic pathway of the “reward center”?
Nucleus Accumbens(NAcc)
Ventral Tegmental Area (VTA)
What do dopamine neurons report/not report in a reward prediction-error signal?
Dopamine neurons report anticipated behavior
Dopamine neurons report an error inn reward behavior
They do not report reward delivery
What are Adrian Raine’s findings about the brains of impulsive murders?
Found reduction in gray matter in prefrontal cortex
How does the prefrontal cortex modulate anger mediated by the amygdala and hypothalamus?
Amygdala: Influences our motivation, emotional control, fear response and interpretations of nonverbal emotional expressions
Hypothalamus: Regulates fear, thirst, sexual drive, sleep and aggression
The PFC utilizes the hypothalamus to regulate aggression from the amygdala
How do halorhodopsin experiments show that attack neurons are specific to the ventrolateral hypothalamus?
Attack neurons in the VMHvl(ventromedial hypothalamus) are necessary to elicit aggression
If attack neurons are necessary, it means that aggression cannot occur without attack neurons
How do channelrhodopsin experiments show that attack neurons are specific to the ventrolateral hypothalamus?
The activation of neurons using channelrhodopsin is sufficient enough to cause aggressive behavior
What happens to flies when they are raised in social isolation vs groups?
Flies raised in social isolation are very aggressive
Flies raised in groups are relatively placid
Describe relative locations of brain regions: anterior/ posterior, dorsal/ventral, lateral/medial, rostral/caudal
Anterior- front of brain, Posterior- back of brain
(side view, horizontal)
Dorsal- top of brain, Ventral- bottom of brain
(side view, vertical)
Lateral- sides of brain, Medial- middle of brain
(top view, horizontal)
Rostral- front of brain, Caudal- back of brain
(angled, horizontal)
Be able to identify the amygdala in a picture
Reference picture
Sensory transduction definition
Convert various forms of energy located outside the body (eg. light rays, sound waves, mechanical forces, or chemicals into neural signals)
Explain how conformational change in retina is responsible for light detection
Rhodopsin molecules in outer segment of a photoreceptor undergoes conformational change when struck my a photon
Classify rhodopsin, transducin, and hyperpolarization as either G-protein coupled receptor, G-protein or downstream effect of G-protein cascade
Rhodopsin: G-protein coupled receptor (GPCR)
Transducin: G-protein
Hyperpolarization: downstream effect of G-protein cascade
How does the unequal distribution of rods and cones of the retina and differences in photoreceptor densities affect vision?
There are more rods than cones, the very middle of the retina only has cones, no rods
The blind spot is where the optic nerve tract is
Memorize the retina and optic tract diagram
Left retina— Right side of left retina= see images from left visual field, Left side of left retina= see images from right visual field
Right retina— Right side of right retina= see images from left visual field, Left side of right retina= see images from right visual field
(retinal images are inverted right to left and top to bottom
Left optic tract— Right visual field
Right optic tract— Left visual field
What is the function of the dorsal stream and ventral stream?
Dorsal: localization and action
Ventral: object identification
Which stream is affected in akinetopsia?
Dorsal stream
Akinetopsia= see snapshots, like if WIFI is going bad in a video game
Which stream is affected in prosopagnosia?
Ventral stream
Prosopagnosia= identifying object
What stimulus would best activate neurons in the fusiform face area?
Eyes
What is the grandmother cell coding scheme?
One neuron is active and collects information from other cells (feature detectors)
What is the population cell coding scheme?
Particular subset of neurons are active, different people activate different subsets
Determine the use of neurons, efficiency and accuracy in the grandmother and population coding scheme?
Neurons= population more, grandmother less
Efficiency= grandmother more, population less
Accuracy= population more, grandmother less
What sensory transduction must be deciphered in the auditory system?
Convert sound (pressure waves in the air) located outside of the body into neural signals
Describe the tonotopic map in the cochlea
Spiral shape
- Base of cochlea(entrance), thicker, higher frequency
- Apex of cochlea(center), thin, low frequency
Different levels of stiffness allows it to tune to particular sounds
Describe the tonotopic map in the auditory cortex
Straight line with ascending numbers
- Low numbers corresponds to apex of cochlea, lower pitch
- High numbers corresponds to base of cochlea, higher pitch `````
What is the relationship between calcium carbonate crystals and vestibular hair cells to vertigo?
Calcium carbonate crystals become stuck with overactive vestibular hair cells causing the crystals to collide with hair cells even when the head is upright and stationary
The brain receives neural impulses that the body is upside down or falling when in actuality the body is stationary
What are the 5 basic tastes?
Sweet, sour, umami, salty, bitter
How are taste buds expressed on the tounge?
Taste buds responsible for different tastes intermixed through the tongue
Classify T1R1, T1R2, T1R3, T2R, gustducin, TRP-M5, and TRP-M4 as either G-protein coupled receptor, G-protein, or TRP channel
T1R1= G-protein coupled receptor (GPCR)
T1T2= G-protein coupled receptor (GPCR)
T1R3= G-protein coupled receptor (GPCR)
T2R= G-protein coupled receptor (GPCR)
(Taste receptors are G-protein coupled receptors)
Gustducin= G- protein
TRP-M5= TRP channel
TRP-M4= TRP channel
(Open at the end of the G-protein cascade)
What taste is activated with T1R1 + T1R3?
Umami
What taste is activated with T1R2 + T1R3?
Sweet
What taste is activated with T2R?
Bitter
Recall the order in which they are activated in the gustatory system
- GPCRs
- Activation of gustducin (G-protein)
- Activation of TRP channels (TRP-M5 & TRP-M4)
What are the characteristics of TRP channels?
Taste receptors are G-protein coupled receptors
TRP channels= transient receptor potential channels (trip channels)
When open, it produces a short depolarization (positive potential)
Non selective cation channels
Activated through diverse mechanisms eg. chemicals, temperature, light, sound, touch
Why does anosmia common after car accidents?
Loss of smell is common after whiplash
The delicate olfactory nerves entering vertically through the cribriform plate are severed which is knife like and cuts all olfactory nerves
How do olfactory nerves detect chemical odorants?
- Olfactory cells have olfactory receptors (type of protein)
- Olfactory nerves are bundles of neurons
- Signals are sent to the olfactory bulb
An odor activates a specific combination of receptors
What is a chemotopic map?
Structurally similar odorants stimulate overlapping but distinct domains in the olfactory bulb
How do touch receptors differ?
The area of sensory space where a stimulus can affect a sensory receptor is diverse in size
How do receptive field size affect touch sensitivity (tactile acuity)?
Tactile acuity= the ability to distinguish between two points of touch stimulation
Tactile acuity is highest when receptive fields are small
What are C fibers?
Slow
Thin
Unmyelinated neurons
Slow conduction velocity
Duller pain
What are A-delta fibers?
Fast
Myelinated neurons
Fast conduction velocity
Sharp initial pain
Where is the homunculus?
Somatosensory cortex
What are the features in the homunculus?
Larger representation for skin with smaller receptive fields associated with higher tactical acuity
eg. fingertips and lips
Less sensitive areas have fewer sensory receptors and larger receptive fields so they take up less space in the somatosensory cortex
How is the homunculus an example of topographic organization?
Spatially adjacent stimuli on sensory receptor surfaces represented in adjacent positions in the cortex
Distinguish impulsive action from impulsive choice
Impulsive action: failure to inhibit an inappropriate response
Impulsive choice: impulsive decision making by choosing small immediate rewards over more beneficial delayed rewards
Predict how risk-averse and risk-seeking rats perform on the rat gambling task
Risk-averse rats: quickly develop a pattern of preference for P2 (win: 2 pellets 80%, lose: 10s time out 20%)
(Display less impulsive choice)
Risk-seeking rats: do not stabilize at preference for P2
(Display more impulsive choice)
How do drugs of abuse affect the mesolimbic pathway?
Drugs trigger abnormally large surges of dopamine in the nucleus accumbens
Dopamine: encodes a reward prediction error signal and is involved in teaching us to learn when to expect a reward
What is the mesolimbic pathway?
Reward pathway, plays an important role in motivation, pleasure and reinforcement of behaviors
How does the brain change after repeated drug use?
The brain enhances its reactivity to drug cues and reduces its sensitivity to non drug rewards
Drugs interfere with the brain’s capacity to exert self control
Drugs render the brain more sensitive to stressful stimuli and dysphoria
What are the stimulant induced dopamine changes in active cocaine abusers?
Stimulant induced dopamine are blunted in active cocaine abusers but cravings continue and are stronger
Results in compulsive drug use, addicts crave more and more to regain lost dopamine signaling
How do brain waves change during sleep stages?
There is a characteristic brain wave for each sleep stage
Brain waves differ in amplitude and frequency
During the course of the night the brain cycles through different brain wave patterns
What is the technique typically used to identify stages of sleep?
EEG, detects brain activity on the outer rim of the brain
What brain regions regulate sleep?
Sleep is regulated by the hypothalamus
What brain regions are observed by the EEG?
Sleep stages are defined by the brain activity on the outer layer of the brain which is where the EEG picks up
What is the circadian process?
Causes sleepiness at defined times in response to environmental cues
What is the homeostatic process?
Causes sleepiness in proportion to time spent awake
What are the signs of sleep deprivation?
Irritability
Cognitive impairment
Memory lapses or loss
Impaired moral judgement
Severe yawning
Hallucinations
Symptoms similar to ADHD
Impaired immune system
Increased heart rate
Decreased reaction time
Tremors
Aches
How can hippocampal place cell activation be used to determine if memories are replayed during sleep?
Place cells in the hippocampus are activated at specific places in a map
What brain regions are affected in a coma?
All regions, however brain stem varies from patient to patient
What brain regions are affected in the vegetative state?
Cerebellum and cortex
What brain regions are affected in a minimally conscious state?
Don’t know exact area
What brain regions are affected in locked-in syndrome?
Pons
Behavior in coma
Neither wakeful nor aware
Immobile with eyes closed
Unresponsive
Behavior in minimally conscious state
Wakefulness with minimal awareness and responsiveness
Sustain gaze at moving target
Reach for offered objects
Speak a few worlds
Express appropriate emotional reactions to stimuli
Behavior in vegetative state
Paradoxical combination of wakefulness without awareness
Wakefulness
Alertness
-Complex reflexes (yawning, swallowing)
-Opens eyes and shows spontaneous roving eyes
-Sometimes smiles or frowns
-Sometimes displays arousal and startle reflexes
-Grasps objects that contact the hand
No awareness
Awareness of self or environment
-No purposeful responses to external stimuli
-Cannot interact with people
-Fecal and urinary incontinence (cannot control poop and pee)
Behavior in locked in syndrome
Full wakefulness and awareness but nearly completely paralyzed
Don’t have voluntary movement of limbs, face, throat, and horizontal eye movement
Cannot move eyes up and down and blink
List 4 criteria used to diagnose people for total brain failure
- Exclude reversible causes eg. low body temperature
- Look for some motor function eg. elicit pain and check for some responses
- Look for brain stem reflexes (cranial nerve reflexes)
- Conduct apnea test:
a) Provide oxygen and check for respiratory movements
b) Measure carbon dioxide content in blood. High carbon dioxide levels should have triggered patient to start breathing
What 2 tests can confirm total brain failure?
EEG measurement of brain activity
Radioactive tracer to examine blood flow into brain (PET SCAN)
Rank a young, old and Alzheimer’s brain for ventricle size and brain tissue volume.
Largest ventricles → Smallest ventricles
Alzheimer’s brain → old → young
Initial brain area affected in AD
Hippocampus
Initial brain area affected in Huntington’s disease
Cortex and striatum
Initial brain area affected in PD
Substantia nigra
Behavior of person with AD
Memory loss and behavioral distrubances
Behavior of person with HD
Chorea, jerky involuntary movements
Behavior of person with PD
Resting tremor, postural instability and gait disturbances
Cellular event occurring in the brain of AD
Extracellular amyloid beta plaques and intracellular tau tangles in neurons
Cellular event occurring in the brain of HD
Degenerated inhibitory neurons (GABA) in the cortex and striatum
Mutant Huntingtin (Htt) protein aggregates in neurons
Multiple CAG repeats predicts the disease
Cellular event occurring in the brain of PD
Loss of dopaminergic neurons in the substantia nigra
Lewy bodies containing alpha synuclein aggregates
What develops from ectoderm?
Epidermis (skin) and nervous system (neurons)
What develops from mesoderm?
Muscle, bone and cartilage
What develops from endoderm?
Lining of guts and lungs
Outline steps of neurulation
Neurulation: process in which the neural tube forms
1) Neural plate elongation
2) Neural plate folds
3) Neural tube closes
Neural plate → neural groove → neural tube → neural axis → brain and spinal cord
What active ingredient in acne medication can cause birth defects?
Isotretinoin
What is the direction in which the layers of the cortex develop?
Inner cortical layers develop first then the rest
What do neural stem cells have the potential to become?
Neurons and glia (astrocytes and oligodendrocytes
What are ES cells?
Embryonic stem cells
Totipotent can give rise to ANY cell type
What are somatic stem cells?
Adult stem cells
Pluripotent, can give rise to most but not all cell types
What are iPS cells?
Induced pluripotent stem cells
Derived from differentiated cells that have received treatment to revert back to immature cells so they can give rise to multiple cell types
What do researchers check in neural stem cells to treat PD?
Grafted cells are not rejected
-Immune system can recognize them as foreign and try to destroy them
Express dopaminergic makers
-Indicates that the grafted cells can produce dopamine, since with Parkinson’s disease there is a lack of dopamine
Don’t have proliferative potential
-Make sure the cells don’t proliferate (rapid cell division)
What is experience dependent plasticity?
Use it or lose it concept
Brain’s ability to adapt and reorganize its structure and function based on experiences and environmental stimuli
What are the structural and functional changes in licensed London taxi cab drivers
Increased hippocampal activity
Increased hippocampus (structural change)
How does the brain change according to experience in the auditory cortex?
Reorganizes to expand regions that are used more often
How does the brain change according to experience in the motor cortex?
Larger representation for a body part when those muscles are used more often
Synaptic plasticity definition
The ability of a synapse to strengthen or weaken over time depending on its activity or lack thereof
What are AMPA receptors?
Open when glutamate binds
When open cations flow in
What are NMDA receptors?
Open when glutamate binds and the postsynaptic neuron is already depolarized
What is the difference between necessary and sufficient?
Necessary= process cannot occur without it
Sufficient= the factor is enough on its own, but it might not be the only way the process can happen
Describe how number of postsynaptic receptors, dendritic spine volume, and number of synapses change with increased or decreased synaptic transmission.
Number of postsynaptic receptors
-Increased synaptic transmission= upregulation or increase of postsynaptic receptors which enhances synaptic strength and activity
-Decreased synaptic transmission= downregulation or decrease or receptors which becomes less responsive
Dendritic spine volume
-Increased synaptic transmission= increase in dendritic spine volume because of the increase in activity
-Decreased synaptic transmission= decrease in dendritic spine volume with reduced synaptic activity or synaptic pruning
