EEOB 4550 Final: Comprehensive + Important Information Only

How can the bat detect the relative velocity of an object from the echo?

***ONLY BATS WITH A CF PORTION OF THEIR CALL CAN DO THIS***. They need to determine the change in frequency They detect the Doppler shift produced from the moving object.

What is the typical voltage inside of a resting cell?

-40 to -70 mV. This is due to the high resistance of Na+ and low resistance of K+ (from K+ leak channels).

What is the voltage of a "K+ battery?"

-70 to -75 mV. This is due to the equilibrium potential of K+.

(From the moth diagram) How was sensitivity measured or quantified, and what does the darker shading mean?

-Sensitivity was measured by determining the volume/intensity of sound needed to produce a response of 2-3 spikes/second in the auditory neurons -Darker shading: lower sensitivity. Need to play sounds louder to get the same response. -Means that the moth's wings are down and covering its ears, so it is less sensitive to sounds above and more sensitive to sounds below

Outline the entire cricket auditory pathway and know where the song-selective neurons are for a syllable rate of 60 syllables per second. State if you expect the female to track this song.

1. Auditory neurons: -In ear -AP frequency matches stimulus frequency 2. Omega neurons in prothoracic ganglion -AP frequency matches stimulus frequency 3. Ascending neurons -In prothoracic ganglion/connective -AP frequency matches stimulus frequency 4. BNC-1 neurons -In brain -Will not respond (low pass neurons) 5. BNC-2 neurons -In brain -Some will respond because they are high-pass neurons -Band pass neurons will not respond because BNC-1 neurons aren't responding and female won't track syllable rate of 60 syllables/second

HVC Experiments

1. Bilateral lesion: No song produced at all. (Can't start motor response). 2. Stimulate: Syllable pattern was disrupted. 3. Record from: HVC neurons fire before the syllable is produce AND respond to playback

How can the bat detect the direction an object is flying from the echo?

1. Horizontal: Based on interaural time differences between the time the echo arrives in each ear. Also small differences in the frequency of the echo. 2. Vertical: due to constructive/destructive interference patterns created by sound in auditory canal vs. sound refracted off of tragus in auditory canal (Tragus = flap in the bat's ear) -Need to have a broad range of frequencies, so need an FM portion of a call for this

Provide two distinctly different examples of responses in an invertebrate that require the use of giant axons.

1. Rapid escape response (cockroach) -Giant interneuron synapses on a motor neuron to allow rapid movement away from a stimulus 2. Coordinated response of large body parts (squid mantle) -Need simultaneous contraction. Small axons go to nearby cells and large axons go to farther away cells.

Stages of bird song learning

1. Sensory 2. Sensorimotor -Subsong -Plastic song 3. Crystallized

What information can bats gather about objects from the echo?

1. Size 2. Distance to object 3. Relative velocity 4. Movement 5. Shape 6. Direction

How can the bat detect the size of an object from the echo?

1. Strength of echo. Larger echo = larger size. 2. For FM bats: higher frequencies reflected = smaller object b/c small objects only reflect the highest frequencies

Drawbacks to giant axons

1. Take up space 2. Are energetically expensive

Circuit Diagram. 1. What direction does charge flow? 2. How do you know which battery is which? 3. How do you know what resistors are which? 4. What do resistors represent?

1. What direction does charge flow? -From negative --> positive. 2. How do you know which battery is which? -The battery showing (-) --> (+) from outside to inside the cell is Na+, because the Na+ ions flow from outside the cell to inside the cell. The battery showing (-) ==> (+) going from inside to outside the cell is K+ because the ions flow from inside to outside the cell. 3. How do you know what resistors are which? -The resistors align next to their respective batteries. A greater value means that there is less permeability of this ion. 4. What do resistors represent? -They represent 1/Permeability.

What is the equilibrium potential of potassium? (Ek)

-70 to -75 mV

If extracellular concentration of Na+ is 150 mM and intracellular concentration of Na+ is 10 mM, at the peak of an action potential when Vm has increased by ~100 mV, one would expect the intracellular concentration of Na+ to be approximately: _______. Why??

10 mM You only need a SMALL AMOUNT of ion movement to cause a large voltage change!! This is due to the fact that ENa+ is very farm from Vm, so when Na+ ions enter, there is a large voltage change.

What are the syllable rates that female crickets track best?

20-40 syllables/second

Where are voltage-gated Ca2+ channels located?

In the presynaptic AXON TERMINAL. When they are opened, Calcium flows into the cell and mobilizes movement of the vesicles with neurotransmitter inside.

What effect does increasing axon diameter have on membrane resistance? Why?

It decreases membrane resistance (Rm). If you increase the axon diameter, you increase the amount of plasma membrane and therefore leak channels present.

What is Rl?

It is the resistance to current moving down the axon. The resistors are in series, so there is a chain of resistance to flowing charge. Resistance increases as you get further away.

Reference frequency

Around 61 kHz. The frequency that the bat needs the 2nd and 3rd harmonic of the echo to be because it has many auditory neurons dedicated to analyzing those frequencies. The bat will lower resting frequency so that the 2nd and 3rd harmonic of the echo return around 61 kHz, where it can best analyze it.

Provide a flowchart to illustrate the neural pathway that processes interaural intensity differences in the barn owl, and indicate where IID information is first combined with information about ITD.

Auditory neuron --> Angular nucleus --> Lateral lemniscal nucleus --> lateral shell of midbrain auditory area --> External Nucleus of midbrain auditory area ITD is first combined with IID in the lateral shell of the midbrain auditory area.

CF-CF region

Region in the auditory cortex that contains combination-sensitive neurons that respond to specific combinations of the CF1 of the outgoing call and the CF2 and CF3 of the echo. Allows bat to determine relative velocity of the moving target.

What property of the membrane causes the peak voltage at each subsequent recording electrode to be smaller than at the previous electrode?

Rl, or longitudinal resistance.

HVC neurons are the link between....

Sensory input and motor output

Doppler shift

The effect on the frequency of the sound heard by an observer due to the sound moving towards or away from the detector. Frequencies appear to be increasingly higher if the sound is moving towards the observer, and increasingly lower if the sound is moving away from the observer.

Bird's own song (BOS)

The final song produced in the crystallized phase. It is not identical to the tutor song but is similar. BOS varies within birds of the same species.

Which types of potentials (action or graded) can be initiated by the opening of membrane channels?

BOTH. Action: Initiated by ligand gated-channels and voltage-gated channels. Graded: Initiated by mechanically gated and ligand-gated channels

Which types of potentials (action or graded) have a transient rather than permanent effect on membrane resting potential?

BOTH. Both types of potentials affect the resting membrane potential transiently.

How can the bat detect the distance to an object from the echo?

Based on the TIME DELAY. (How long it takes for the signal to come back).

Doppler Shift Constant Frequency (DSCF) Region

Brain area in bats that facilitates the bat's ability to perform Doppler shift compensation. Simply increases the SPEED at which it can compensate; it does not control it completely.

Harmonics

Higher multiples of the base/fundamental frequency. The cries from the bat and echoes will carry the fundamental frequency + harmonics. Ex: FF is 30.5 kHz; 2nd harmonic is 61 kHz

Where does a graded potential occur?

In the dendrites/cell body of the post-synaptic cell

Where are space-specific neurons found?

In the external nucleus of the midbrain auditory area

Describe the response of BOTH fish involved in avoiding the jamming (JAR) response.

In the fish with the higher frequency, Df is <0 so the neurons in the prepacemaker nucleus will increase the firing rate of pacemaker neurons and the EOD, increasing the frequency of the electric output. In the fish with the lower frequency, Df >0, so the neurons in the prepacemaker nucleus will decrease the firing rate of pacemaker neurons and the EOD, decreasing the frequency of the electric output.

Where are synaptic vescicles located?

In the presynaptic axon terminal

How is intensity encoded in the owl's pathway, i.e. how does the neural response change as intensity increases or decreases?

Intensity is encoded by the action potential firing rate. As intensity increases, action potential firing increases, and as intensity decreases, action potential firing decreases.

What is JAR? Why is it necessary?

JAR is a reflex that occurs in active electrolocators. It occurs when the fish senses a frequency of an electric field produced that is within 3 to 4 kHz of its own frequency that it produces. The JAR response prevents a combination of similar frequencies that would prevent the electroreceptors from obtaining useful information from the environment. It allows the fish to navigate in the presence of a conspecific.

What constant is used to describe this decrease in voltage? Briefly explain the value of the constant and state which one of the recording electrodes (A-F) is located closest to the value of the constant.

Lamda, the length constant. Lamda describes the degree to which Vm changes as a function of distance from the origin. It is the distance at which Vm has decreased to 37% of its original value! Electrode (C) is closest to this value because this is where the voltage is 63% of the original voltage.

Example of an FM bat

Little brown bat. Hunts in the open air.

What effect does myelination have on membrane resistance? Why?

Myelin increases Rm because there cannot be ion channels underneath the myelin.

Which types of potentials (action or graded) requires diffusion of Na+ and K+ through the Na+/K+ ATPase?

NEITHER.

Space-specific neurons

Neurons found on the external nucleus of the midbrain auditory area that fire and correspond to sound in a particular region of space

Where are ligand-gated ion channels located?

On the post-synaptice cell

What is Ontogeny? How does it relate to the egg-rolling behavior seen in geese? Is it a proximate or ultimate cause?

Ontogeny: How/When does the behavior appear? The behavior is seen when a mother goose is sitting on the nest and sees an egg outside of the nest. PROXIMATE CAUSE

Canaries

Open learners that can have repeated learning

The Vm will approach the equilibrium potential with the greatest _______

PERMEABILITY. This is because resistance to that ion decreases, so the ion can move along its concentration gradient either into/out of the cell.

What order do songbirds belong to?

Passeriformes. Suboscines: do not learn to sing Oscines: learn to sing

What is phase ambiguity? Why does it occur?

Phase ambiguity is the fact that if the ITD is such that you have one complete sound wave difference, the owl can't tell which one came first. It occurs because the owl is using ongoing disparity to determine interaural time differences.

Frequency Modulated (FM) Bat

Produces a "sweep" of frequencies that start high and go lower. Hunt in the open because they cannot detect the relative velocity of their moving prey (can't distinguish prey from another small object like a leaf).

Tuberous Ampullae of Lorenzini

Receptors found only in species of active electrolocators (freshwater fish that produce an electric field). They are LESS SENSITIVE and have a wider opening.

Sensory phase of bird song learning

Recognition and memorization of the tutor song occurs and the brain forms a song template (memory formed that the bird can retrieve later). This occurs right after hatching and it is best for learning if this occurs when the bird is very young.

Quality factor (Q)

Reflects the tuning/selectivity of a particular neuron. Higher Q = more selective Lower Q = less selective From diagram: can determine this by looking at the width of the "V" for a particular frequency. Narrow V means that you had to play the sound louder for get a response = higher Q.

Anterior forebrain pathway (AFP)

Region in the bird's brain that is vital for SONG LEARNING. It provides input to the song system. As the bird matures, the neurons become increasingly selective for the BOS. (Suggests that neurons are changing as the bird learns the song).

What are CF portions of calls used for detecting?

Relative velocity (Doppler shifts). Auditory neurons have poor time resolution but high Q at CF2, lower Q at CF1 and CF3.

Phase-locked neurons

Specific neurons found on the COCHLEAR BASILAR MEMBRANE that fire only at a particular phase at a given frequency. (Ex: Fire at 90° of the sound wave. Don't have to fire every single time it hits 90°, just reliably.)

Sensorimotor phase of bird song learning

Split into 2 subphases: 1. Subsong: Birds are practicing with their oral/vocal musculature, but are producing nonsensical vocalizations like babbling. (innate) 2. Plastic song: Testosterone increases and birds are practicing the tutor song. They listen and modify as the song begins to resemble the tutor song.

White-crowned sparrows

Studied a lot in the field. Seasonal species Non-overlapping phases of learning

Zebra finches

Studied a lot in the laboratory--quick learners Aseasonal species Overlapping phases

What is Survival value? How does it relate to the egg-rolling behavior seen in geese? Is it a proximate or ultimate cause?

Survival Value: How does the behavior contribute to survival and reproductive success? This behavior directly increases fitness by increasing the chance of survival for the offspring. ULTIMATE CAUSE

What constant is used to describe this gradual rise in voltage? Briefly explain the value of the constant.

Tau, the time constant. T= RC Tau is the time required for the change in membrane potential to reach 63% of its final value. Depends on Capacitance.

Where are phase-locked neurons found in the owl?

The basilar membrane of the cochlea

Tutor song

The conspecific song that young birds need to hear and memorize during the sensory phase in order to produce their own song later on.

Resting frequency

The frequency that the bat emits. Generally it is on the lower boundary of the CF1 and will adjust it to compensate for the Doppler shifted echo--in order to keep it in the reference frequency area.

Threshold

The membrane voltage at which 50% of the voltage-gated Na+ channels have opened. Results in an action potential!

Example of a CF-FM bat

The mustached bat. Hunts in dense vegetation

What do the neurons that encode for ITD respond to? Where those neurons are located?

The neurons that encode for ITD are coincidence detectors that are in the laminar nucleus. They encode for ITD based on responses to firing of phase-locked neurons from the right and left ears. They can only encode the time interval between the right and left responses, not which ear heard the sound first.

Crystallized phase of bird song learning

The plastic song becomes fixed and crystallized into the bird's own song.

Equilibrium potential of an ion

The voltage at which there is no net movement of the ion along its concentration gradient.

How can the bat detect the movement of an object from the echo?

The wing movements of moths will create small fluctuations in the echo (Only bats with a CF portion of their call can detect this).

Characteristics of giant axons

They increase lamda and decrease tau, so they increase the conduction velocity.

Bird call

Unlearned, innate vocalization that is produced when the bird is threatened. All birds can do this.

In a neuron at rest, if the extracellular and intracellular concentrations of Cl- are 100 mM and 10 mM respectively, what is ECl-?

Use Nernst Equation! Ez = 60/z log ([Xout] / [Xin]) ***MAKE SURE TO USE -1 FOR Z*** = -60 log (100/10) = -60 mv

Is hearing the song while practicing important for learning?

YES. The birds need hearing to learn and practice a tutor song! They are comparing what they heard to the memorized song.

RA

Area in the bird's brain that is responsible for: -Controlling the notes within each syllable

HVC

Area in the bird's brain that is responsible for: -Starting and stopping the bird's song -Timing instructions -Generating the sequence of syllables -Receives sensory input (responds to playback)

Medial geniculate body

Area in the midbrain where combination sensitive neurons in the CF-CF and FM-FM pathways provide information about velocity (CF-CF) and distance (FM-FM). Outputs are then sent to the CF-CF and FM-FM regions in the auditory cortex.

Which types of potentials (action or graded) are important for information processing in a neuron?

GRADED POTENTIALS. Graded potentials can summate/cancel out, so they are important for processing information in a neuron.

Bird song

A complex vocalization usually produced by males. An acoustic flag that attracts females and defend a territory. It is a learned behavior.

Timbal Organ

A structure on the sides of some moth species that bends to make an ultrasonic clicking noise to defer bats.

Weakly electric fish use electroreceptors in Ampullae of Lorenzini with _________ shape to detect the electric field produced by their electric organ

A tuberous

Syrinx

A vocal organ in birds located at the base of the bird's trachea that allows production of complex sounds. There are 2 structures, with different muscles to control the left and right sides, so the bird can produce 2 sounds at once.

Which types of potentials (action or graded) include a relative refractory period?

ACTION POTENTIALS. Action potentials have refractory periods, which is when the neuron cannot respond/doesn't respond easily to a 2nd stimulus. However, Graded potentials do not have this, and this fact allows them to summate.

Which types of potentials (action or graded) always result in depolarization of the membrane?

ACTION POTENTIALS. Graded potentials can be depolarizing or hyperpolarizing.

Which types of potentials (action or graded) cause subsequent change in the passive properties of the membrane?

ACTION POTENTIALS. Passive properties of the membrane are Rm and C (Membrane resistance and Capacitance). Graded potentials are simply a passive diffusion of charge.

Which types of potentials (action or graded) require voltage-gated ion channels?

ACTION POTENTIALS. Voltage-gated ion channels allow propagation of the axon potential down the axon.

Where are voltage-gated Na+ channels located?

Along the axon of the presynaptic neuron

Where does an action potential occur?

Along the axon of the presynaptic neuron

Where is myelin located?

Along the axons of neurons

What property of the membrane causes the voltages measured along the axon to rise gradually rather than immediately?

Capacitance. Electrotonic spread is influenced by capacitance because the time it takes for the charge to "detach" from the capacitor and move causes a change in the rate at which the Vm changes. Capacitance makes the change in Vm gradual rather than sudden!!

What is Causation? How does it relate to the egg-rolling behavior seen in geese? Is it a proximate or ultimate cause?

Causation: What stimuli elicit the response? A white, round, egg-shaped stimulus or egg elicits the behavior. PROXIMATE CAUSE

What kinds of neurons does the DSCF region contain?

Combination-sensitive neurons that respond to specific frequency and amplitude combinations in the echo.

Copulation solicitation assay

Counts the number of times a female displays a receptive posture when tested with a bird song. Allows experimenters to determine if the female recognizes the song.

Ampullary Ampullae of Lorenzini

Found in all electroreceptive fish (active and passive). More sensitive and can be used to detect a relatively weak electric field. Flask shaped.

Which types of potentials (action or graded) normally cause a Vm change of 20 mV or less?

GRADED POTENTIALS.

In which types of potentials (action or graded) does the magnitude of the voltage change reflect the intensity of the stimulus?

GRADED POTENTIALS. An action potential is an "all or none" phenomenon. Graded potentials can be graded to different degrees.

Descending motor pathway of bird song

HVC ---> RA ---> muscles of the syrinx

What are FM calls useful for determining?

Distance. Neurons have good time resolution, but poor Q (selectivity for frequency).

How can the bat detect the shape of an object from the echo?

Due to different interference patterns as sound reflects off of different parts of the object's body. -Need FM portion of a call for this

Constant Frequency-Frequency Modulated (CF-FM) bat

Emits a constant frequency followed by a downward FM sweep. Hunt in areas with dense vegetation b/c they can detect the relative velocity of their moving prey (can detect Doppler shifts).

What is Evolution? How does it relate to the egg-rolling behavior seen in geese? Is it a proximate or ultimate cause?

Evolution: How did the behavior arise in the species? This behavior evolved because the females exhibiting it produced more offspring with genes that carried for this behavior/also exhibited this behavior. ULTIMATE CAUSE