CBIO 3800 Chapters 1, 2, 3, and 4 Quiz Questions

A researcher conducts a voltage clamp experiment on a giant squid axon. She clamps a typical neuron at 0mV. Which graph in the figure below represents the current changes she will observe?

A

Which observation was not observed in Hodgkin and colleagues' voltage-clamp study of squid action potentials?

A sustained outward current as a result of hyperpolarization

Which property is characteristic of Na+ channels but not K+ channels?

Ability to inactivate

Which symptom(s) is characteristic of patients with multiple sclerosis?

Abnormal somatic sensations due to lesions of somatosensory pathways

Work done by _______ and _______ elucidated changes in membrane permeability that underlie an action potential.

Alan Hodgkin; Andrew Huxley

Which statement is a common, defining feature of membrane-bound active ion transporters?

All are able to move at least one ion against its concentration gradient.

Which of the following is not a type of ion transporter that has been observed?

All of the transporters listed here have been observed.: The sodium/calcium exchanger; The sodium/potassium/chloride co-transporter; The sodium/neurotransmitter co-transporter; The sodium/proton exchanger

Which statement does not stem from the application of Ohm's law to ionic conductances?

All permeant ions experience an identical driving force at each time point during the course of an action potential.

Which of the following is the main reason that the opening of sodium channels causes a very rapid depolarization of most neurons?

Because of the large sodium gradient created by membrane transporters, a rapid depolarization occurs whenever sodium channels are opened in resting neurons.

In what way are ion channels similar to active transporters?

Both are proteins.

Which brain research method is associated with the greatest safety concerns?

Computerized tomography

What would occur if the ATPase pumps in a neuron stopped functioning?

Concentration gradients would not be maintained across the membrane

Which intracellular component facilitates the processes of endocytosis and exocytosis underlying synaptic communication?

Cytoskeleton

Which of the following was observed in studies measuring the efflux of radioactive sodium from the squid giant axon?

Decrease of efflux when mitochondrial ATP synthesis was inhibited Dependence of efflux upon the presence of ATP Recovery of efflux when extracellular potassium was restored Sharp drop in efflux when extracellular potassium was removed

In the figure, the structure labeled_______ is the main target for incoming signals received from the axons of other cells.

Dendrites

Which toxin is not correctly paired with its mechanism of action?

Dendrotoxin—slows the activation of K+ channels

Which of Camillo Golgi's contributions enabled Santiago Ramón y Cajal to make observations that suggested that nerve cells are discrete entities?

Development of a staining method based on impregnation with silver salts

The classic voltage clamp technique would be suitable for which application?

Direct measurement of current flowing through the cell membrane

Which statement regarding membrane potential and equilibrium potential is true?

Equilibrium potential is affected by the concentration and electrical gradients of one ion; membrane potential is affected by gradients of all ions.

Which statement accurately describes neural and glial cells?

Exocytosis and endocytosis are important for synaptic communication.

Which part of the gene (genomic DNA) is also found in messenger RNA (mRNA)?

Exon

The equation used to calculate membrane potential when there are multiple permeant ions is called the _______ equation.

Goldman

Which property of the action potential do the graphs in the figure illustrate?

All-or-none

Which statement best describes the action potential?

An action potential occurs when the cell's membrane potential reaches threshold.

Which of the following is not integral to the action potential waveform?

An initial decrease in the potassium current

In the experiments conducted by Hodgkin and Huxley, the early current disappeared if the membrane was clamped at _______ mV.

+52

In voltage clamp experiments, the early current will disappear if the membrane is clamped at _______ mV.

+52

Which conclusion can be drawn from Hodgkin and Huxley's studies of K+ and Na+ conductances?

- Both conductances exhibit the property of time-dependent activation; - Both conductances depend on voltage; - K+ conductance reaches its maximum with a pronounced delay; - Unlike K+ conductance, Na+ conductance reaches its maximum and inactivates rapidly.

The resting membrane potential typically ranges from _______ to _______.

-40 mV; -90 mV

What is the primary pathophysiological mechanism associated with multiple sclerosis?

Immune response within the nervous system

Which of the following is not an established role for glial cells?

Integrating information to assist neural computation

Which current is produced in response to a hyperpolarizing stimulus in a giant axon of a squid?

Inward capacitive current

Which of the following is a major advantage to researchers of the Xenopus oocyte expression system?

It facilitates physiological characterization of modified ion channel genes.

Which statement about Na+ permeability during an action potential is most accurate?

It is responsible for the rising phase of the action potential.

Which of the following statements about a structure found at the N-terminal of some types of potassium channels is true?

It may serve as a plug or inactivation gate

Which statement about passive current involved in action potential propagation is most accurate?

It opens voltage-dependent Na+ channels in the adjacent region of axon.

Which statement about multiple sclerosis (MS) is false?

It was recently proven that all cases of MS are due to persistent infection by a tropical parasite.

In a two-compartment model of a cell with a K+- and Cl--permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Cl- ions?

It would become positive

Membrane potential depolarizes, Na+ channels open, Na+ current increases, _______.

K+ channels open

Which channel(s) is(are) implicated in inherited forms of epilepsy?

K+, Ca2+, and Na+

What type of ion channel is depicted? potassium entering the channel with what appears to have a Ca2+ attached to the channel

Ligand-gated K+ channel

Which experimental model did Hodgkin and Katz use in their studies of the resting membrane potential?

Living squid neuron

Compare spatial and temporal resolution of functional magnetic resonance imaging (fMRI) to those of magnetoencephalography (MEG).

MEG provides greater a greater temporal resolution than fMRI along with a greater spatial resolution.

What characteristics of magnetic resonance imaging make it such an attractive research tool?

MRI is a safe, noninvasive procedure that provides useful images of structure and brain function. It is also cost-effective

Which statement accurately describes the difference between bacterial and mammalian channels that are selectively permeable to K+?

Mammalian K+ channels have four additional structures that act as voltage sensors.

Which statement about myelination is false?

Myelin serves to sharply increase the time constant of the axon.

Which ion is transported down its concentration gradient by transporters?

Na+

Which statement about voltage-gated ion channels is true?

Na+ and K+ channels can work independently of one another

Which transporter plays a key role in maintaining the concentration gradients of ions in the brain that are critical for generating electrical signals?

Na+/K+ ATPase pump

What does the figure depict? Na+, K+, Cl- entering the cell

Na+/K+/Cl- co-transporter

Draw a simple diagram of a neuron and label its components. In what ways are neurons specialized for communication? How do these specialized features distinguish neurons from other types of cells?

Neurons have axons and dendrites, structures for maintaining and transmitting electrical potential, and synapses, all of which allow neurons to establish connections and share information

Glia are at least as numerous as neurons in the brain, yet neurons are the predominant focus of neuroscience research and discussion in textbooks. Why?

Neurons transfer signals that affect the behavior and cognitive functions of people. Glia cells help the neurons in transferring information to specific locations

Which cell type forms the structure labeled C in the figure? the myelin sheath on the axon

Oligodendrocytes in the central nervous system

What is the net charge transported by one cycle of the Na+/ K+ ATPase pump?

One positive charge leaves the cell

A transgenic mouse animal model is created that expresses both the Cre recombinase gene, under control of a promoter for a gene expressed only in muscle fibers, and an androgen receptor with loxP sites around exon 2. How will expression of the androgen receptor protein be altered in the transgenic mouse?

Question 5 options: The mouse will not express androgen receptor in muscle fibers.

What is the role of interneurons in the knee-jerk reflex?

Relaxation of flexor muscles

Which treatment was shown to eliminate the early inward current in squid giant axons?

Removal of external sodium

Which intervention will disrupt the function of the Na+/K+ ATPase pump?

Removal of extracellular K+

Practically speaking, how would you determine that Na+ influx into a cell underlies the early current?

Remove Na+ from the extracellular compartment and assess the early current under new conditions.

The major proponent(s) of the neuron doctrine was(were)

Santiago Ramón y Cajal; Charles Sherrington

Which cell produces myelin in the nerves of the peripheral nervous system?

Schwann cell

The type of glial cells that myelinate peripheral axons are called

Schwann cells.

A researcher conducts a voltage clamp experiment on a giant squid axon and collects the data shown in the graph. At what membrane potential was the cell clamped?

Sodium's equilibrium potential

Referring to the cartoon below, what is the function structure C? myelin sheath

Speeds up conduction of an action potential

A mouse model is created through Cre/lox technology in which a gene is knocked out of the central nervous system only. Which region would continue to express the protein made by the gene?

Spinal nerves

Referring to the cartoon below, where will voltage-gated Na+ channels be most abundant? an axon image with various components

Structure D, node of ranvier

Which statement describes one of the features of Hodgkin and Huxley's mathematical model?

The action potential can be reconstructed based entirely on the time course and amplitudes of the ionic conductances.

Which statement correctly differentiates between the passive and active current in a myelinated axon?

The active current flows only in the nodes of Ranvier, unlike the passive current.

Which evidence supports the assertion that the macroscopic Na+ current is the sum of many microscopic Na+currents?

The averaged collective response of single channels resembles the time course of the macroscopic current.

Which statement below does this graph illustrate?

The behavior of Na+ channels is voltage dependent.

Which ligand-gated ion channel is regulated primarily by an intracellular signal?

The cAMP- and cGMP-gated ion channels

A neuron has received enough stimulation to fire an action potential; it also has been treated with TEA, a K+ channel blocker. Which outcome is possible?

The cell will initially depolarize, but repolarization will take much longer because it relies only on ion pumps.

In the following figure, which of the following is the key event at a membrane potential of 26 mV?

The late outward current decreases in magnitude

In the following figure, which of the following is the key event at a membrane potential of -26 mV?

The late outward current increases in magnitude

Which of the following is NOT considered to be a "model" organism?

The marine snail Aplysia

Which consequence of Na+ channels staying open, instead of closing after membrane depolarization, is most plausible?

The membrane would not repolarize (return to a negative value of membrane potential) following depolarization.

Which phenomenon explains the unidirectional propagation of action potentials?

The presence of a refractory period at a location where an action potential has just passed

Which statement regarding refractory periods is true?

The refractory period ends when the sodium channels are no longer inactivated.

What do microscopic and macroscopic Na+ currents have in common?

They represent a flow of many ions

Which current corresponds to a flow of Na+ in response to a depolarizing stimulus in a giant axon of a squid?

Transient inward current

Which function is a characteristic primarily of neurons only, and not glia?

Transmits action potentials

For which reason was the development of the voltage clamp critical to investigations of the ionic basis of the action potential?

Voltage clamping allows simultaneous control of membrane potential and measurement of permeability changes.

A patient presents with migraines that usually last about 48 hours and are accompanied by vomiting. Two of his immediate relatives show similar symptoms. Which ion channel would you expect to be dysfunctional in this patient?

Voltage-gated calcium channel

Which observation is not evidence that helped to identify sodium as the early current of the action potential?

When the late current was blocked, the reversal potential of the inward current shifted to a negative membrane potential.

Which statement regarding the diversity of ion channels is false?

With only six different types, potassium channels are the least diverse channel type.

The technique that provides the most direct information about the physical, three-dimensional structure of ion channels is

X-ray crystallography.

The type of nerve cell that synapses upon muscles is called

a motor neuron (or motoneuron)

Which technique(s) would one use to: (a) find the boundaries between layers of the cortex; (b) determine where the axons from nucleus X project; (c) visualize neurons that make protein Y; and (d) examine the dendrites of neurons in region Z?

a) Nissl stain b) administration of radioactive or fluorescent tracers c) Immunohistochemistry; in situ hybridization d) Immunohistochemistry using antibodies against dendrite proteins

GFP stands for:

a. "green fluorescent protein" (a genetic reporter).

Which of the following statements about action potentials is true?

a. Action potentials can transmits signals over long distances. b. Action potentials can amplify small signals. d. Action potentials occur at threshold. e. Action potentials are all-or-none.

Which feature distinguishes the four model organisms (mouse, zebrafish, fruit fly, and nematode) from other animals that have been intensively studied by neuroscientists?

a. Ease of genetic analysis and manipulation

Which of the following statements about neural or glial cells is (are) false?

a. Glial cells rapidly transmit long-range electrical signals. e. The endoplasmic reticulum is concentrated in axons.

Concentrations of which ion, inside and outside of a neuron, have the greatest effect on the resting membrane potential?

a. K+

A friend has taken a job in a neuroscience research lab, and is studying neurons in a freshwater snail. He has been told to calculate the equilibrium potential of K+. Which equation will he use and what other information will he need?

a. Nernst equation; concentration of K+ inside and outside of the cell

Which state of the plasma membrane does not occur during an action potential?

a. Resting phase

Which factor is important in determining the membrane potential when there are multiple permeant ions?

a. The concentration gradient of the individual ionic species b. The permeability of the membrane to the individual ionic species

Which of the following factors is important in determining the membrane potential when there are multiple permeant ions?

a. The concentration gradient of the individual ionic species b. The permeability of the membrane to the individual ionic species d. The valence (electrical charge) of the permeant ion

In a two-compartment model of a cell with a K+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would K+ ions flow across the membrane?

a. They would flow from the inside compartment to the outside compartment

Under which circumstances is the Goldman equation equivalent to the Nernst equation?

a. When a membrane is permeable to only one ion

In the mature central nervous system, glial stem cells with the properties of astrocytes can give rise to:

a. astrocytes; b. neurons; c. oligodendrocytes

Studies of the ionic basis of the action potential in squid giant axon found that

a. decreasing sodium outside the cell decreases the amplitude of the action potential.

Studies of the ionic basis of the action potential in squid giant axon found that

a. decreasing sodium outside the cell decreases the size (amplitude) of the action potential.

In their studies of the resting membrane potential of the squid giant axon, Hodgkin and Katz found that:

a. increasing potassium outside the axon depolarized the axon's potential.

Hodgkin and Katz proposed that sodium was the predominant ion associated with the firing of an action potential because

a. the membrane potential approaches the Na+ equilibrium potential during the rising phase.

An action potential is a(n) _______ change in the electrical potential across the nerve cell membrane.

all-or-nothing

Structures that form the voltage sensors of K+ channels

are embedded in the cell membrane.

Which method was used to visualize the retinal neurons shown in this figure? yellow staining of the cell

b. Intracellular injection of a fluorescent dye

Which statement about electrochemical equilibrium is true?

b. It occurs when the potential across the membrane exactly offsets the concentration gradient.

During which phase of an action potential does membrane permeability to Na+ exceed membrane permeability to K+?

b. Rising and overshoot phases

The scientist who shared the Nobel Prize with Camillo Golgi for his anatomical studies of the CNS was

b. Santiago Ramon y Cajal.

Which statement about ionic distributions in nerve cells is true?

b. Sodium is higher outside cells than inside cells.

A dull probe stimulates a Pacinian corpuscle. An electrode is placed midway down the axon, and action potentials are recorded. After one second, the probe is pushed with greater force. What change will occur in the recording?

b. The frequency of action potentials will increase.

Compared with projection neurons, axons of local circuit neurons (interneurons)

b. are shorter.

Neurons firing action potentials encode a signal's intensity typically by

b. changing the frequency of their action potentials.

The transmembrane potential is generated by

b. diffusion of ions down a concentration gradient.

In the phase labeled B, _______ ions are moving _______ the cell.

b. sodium; into

The in situ hybridization method is based on:

b. using nucleic acid probes to detect mRNAs that encode specific proteins.

The paddle-like, charged transmembrane domains of potassium channels may

be the primary voltage sensors.

Animal toxins have been discovered that:

block sodium channels. alter the voltage-dependence of sodium channels. prolong the open state of sodium channels. block potassium channels.

Which of the following is not a cause of sensory receptor potentials?

brain waves

The brain imaging technique that makes use of a narrow X-ray beam is called

c. CT.

Which technique first produced unequivocal support for the neuron doctrine of the nervous system (as opposed to the reticular theory)?

c. Electron microscopy of nervous tissue

Which statement about the ionic permeability of cell membranes is false?

c. In resting nerve cells the membrane is quite permeable to potassium.

Which statement about the ionic permeability of cell membranes is true?

c. In resting nerve cells, the membrane is quite permeable to potassium.

Which statement about a center-surround receptive field is false?

c. It is found only in primary sensory cortex.

Which statement best describes the Nernst equation?

c. It relates the equilibrium potential of an ion to its intra- and extracellular concentrations.

In a two-compartment model of a cell with a K+- and Na+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions?

c. It would not change.

The structural brain imaging technique that relies on atoms behaving as small magnets is called

c. MRI

Which statement accurately describes the expression of genes in the nervous system?

c. Most of the genes in the human genome are expressed in the CNS.

Which of the following is not necessary for neurons to communicate electrically?

c. Separation of large amounts of electrical charge, with excess positive charges stored inside the cell

How does the resting membrane potential of a typical neuron compare to the equilibrium potential (calculated by the Nernst equation) for potassium?

c. The resting membrane potential is not exactly equal to the equilibrium potential for potassium because the membrane has some resting permeability to species other than potassium.

Which statement best describes most neurons?

c. They are polarized.

The resting potential of a cell is negative because

c. at rest there is an excess of K+ inside the cell, and the membrane is permeable chiefly to K+.

An advantage that intracellular recordings have over extracellular recordings is that they:

c. can record synaptic and receptor potentials.

The resting membrane potential is not exactly equal to the Nernst potential for potassium because

c. the membrane has some permeability to species other than potassium.

Cognitive neuroscience is concerned with

consciousness; emotions; memory; language

This figure shows patterns of action potentials (vertical lines) in neurons that form the neural circuits for the knee-jerk reflex. Which pattern represents the activity of a flexor motor neuron?

d. Bottom

Which statement best describes the function of a neuron with multiple, highly branched dendrites and one axon?

d. It integrates information from many neurons.

Which stimulus is most likely to evoke an action potential?

d. Large depolarizing current pulse

How does membrane permeability to K+ (PK) and Na+ (PNa) change during an action potential?

d. PK exceeds PNa at rest; PNa temporarily increases during the action potential.

Which of the following is not a usual kind of potential exhibited by nerve cells?

d. Reaction

Which of the following is not necessary for neurons to communicate electrically?

d. Separation of large amounts of electrical charge, with excess positive charges stored inside the cell

Which of the following is not part of the brain?

d. Spinal cord

In the knee-jerk reflex, the afferent neurons

d. are sensory neurons

The different electrical signals occurring in nerve cells are caused by _______ the cell membrane.

d. fluxes of ions across

Antibody staining is used to

d. visualize the distribution of specific proteins in the nervous system.

Voltage clamp data, in which investigators analyzed membrane conductances during action potentials, showed all of the following except

depolarization leads to a time-dependent inactivation of the potassium current.

Which of the following is a feature that distinguishes model organisms from other animals that have been intensively studied by neuroscientists?

e. Ease of genetic analysis and manipulation

Which of the following statements about electrochemical equilibrium is false?

e. For a given concentration gradient, the resulting potential is independent of the number of charges on the ion.

Which of the following statements about the expression of genes in the nervous system is true?

e. Most of the genes in the human genome are expressed in the CNS.

In the adult central nervous system, there is typically an excess of _______ in the extracellular compartment, relative to the intracellular compartment.

e. Na+, Cl-, and Ca2+

In a two-compartment model of a cell with a K+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions?

e. No potential would be generated.

What is the major determinant of the permeability of a membrane to a specific ion?

e. Number of open ion channels specific for that ion

A doctor taps the right knee in an individual who was in a car accident and has sustained damage to the right dorsal root of the lower spinal cord. Which motor response would you expect?

e. Right leg remains motionless

Which of the following statements about ionic distributions in nerve cells is false?

e. The total concentration of all ionic species is approximately the same for all nerve cells in all animals.

Which statement about active ion transporters is true?

e. They move certain ions against the concentration gradient.

Why is the white matter lighter in appearance than the gray matter?

e. White matter is richer in myelin, which reflects more light than gray matter.

The amplitude of the action potential of a given neuron is

e. always the same.

Genomics is the analysis of:

e. coding and regulatory DNA of an individual organism or a species

Subthreshold current injected into an axon flows _______ along the axon and _______ with distance from the site of injection.

e. passively; decays

The neurons whose synaptic connections with glandular cells trigger stomach secretions are located in:

e. the ganglia embedded in the wall of the stomach.

The set of neurons and small ganglia associated with the digestive tract is called the _______ nervous system.

enteric

The K+ channel is made up of _______, each of which contains helical membrane-spanning domains with a _______ between them.

four subunits; pore loop

Nodes of Ranvier represent

gaps in myelin wrapping.

The TRP ion channel family includes channels responsive to

heat and cold.

Neuroethology is the field devoted to studying complex behavior

in the native environment.

In the phase labeled D, the voltage-gated sodium channels are ________ and the voltage-gated potassium channels are ________.

inactivated; open

During the knee jerk reflex, the role of the spinal interneuron is to _______ the _______ muscle, allowing the leg to _______.

inhibit; flexor; extend

The voltage clamp method controls the _______ at any desired level.

membrane potential

Which glial cell type serves as a resident immune cell in the central nervous system?

microglia

In a two-compartment model of a cell with a K+-permeable membrane, at K+ equilibrium potential, there is _______ flux of K+ ions.

no net

Most neurons have

one axon hillock (initial segment).

In the phase labeled B, the voltage-gated sodium channels are ________ and the voltage-gated potassium channels are ________.

open; closed

In the phase labeled D, _______ ions are moving _______ the cell.

potassium; out of

The _______ most directly affects the rate of information processing within the central nervous system.

propagation speed of action potentials

The part of a synapse to which the contents of synaptic vesicles bind is called the

receptor

An action potential travels in only one direction along the axon because of its _______ property.

refractory

A neuron that receives a large number of synaptic inputs from other neurons

represents convergent neural signaling

A neuron that innervates (i.e., makes synaptic contact with) a large number of other neurons

represents divergent neural signaling.

A surprising result that emerged from the molecular and genetic analysis of ion channels was the

sheer number of different ion channels.

Which anatomical term denotes a component of the peripheral nervous system?

spinal nerve

The technique that first revealed the tremendous diversity of neuronal cell types, by revealing different cell bodies along with their processes, is

the Golgi technique (stain)

When current is injected into an axon,

the current will decay exponentially with increasing distance from the injection site (if no action potential is present).

The squid giant axon is useful in neuronal studies because

the cytoplasm in the axon can be extruded, thus allowing studies of its composition.

In the operation of sodium-potassium ATPase,

the pump can slightly hyperpolarize neurons following a heavy influx of sodium. there is an obligatory coupling of sodium efflux and potassium influx. the pump transports two potassium ions for every three sodium ions. this transporter (or "pump") is electrogenic.

In familial hemiplegic migraine, the underlying mutation in a calcium channel causes

the syndrome by some unknown mechanism.

The voltage clamp apparatus has _______ electrodes, and the _______ compares the actual membrane potential with the command potential.

three; amplifier

A K+ inward rectifier channel has

two transmembrane domains and a pore loop, but no voltage sensor.

Ion channels that are involved in generation of action potentials open or close in response to

voltage.

Which of the following is a mechanism by which the potassium-channel selectivity filter selects for potassium?

The channel pore narrows to fit the size of a non-hydrated potassium ion. Cations such as cesium are too large to pass through the pore.Cations such as sodium are too small to be dehydrated at the pore filter.

Which statement on the rising or overshoot phase of the action potential is true?

The degree of depolarization is limited in part by the inactivation time course for the sodium current.

In the following figure, which of the following is the key event at a membrane potential of 65 mV?

The early and late currents flow outward

In the following figure, which of the following is the key event at a membrane potential of 0 mV?

The early current is at its maximum

In the following figure, which of the following is the key event at a membrane potential of 52 mV?

The early current reverses its polarity

In which part of a neuron would most of the endoplasmic reticulum be concentrated?

Cell body

Which technique is illustrated in the figure, and what can it be used to measure?

Cell-attached patch clamp; measures the current that flows through a single ion channel

From which part of the nervous system do cells that innervate neuromuscular junctions originate?

Central nervous system (CNS)

Which statement about astrocytes is true?

They play a role in the formation of the blood-brain barrier.

Which structures are included in the central nervous system (CNS) and which are part of the peripheral nervous system (PNS)?

CNS: brain and spinal cord PNS: sensory neurons that link their receptors with the CNS, as well as the motor axons that connect muscle, cardiac muscle, and glands (visceral motor division)

Which process(es) underlie(s) the refractory period?

The slow time course of turning off K+ conductance activation and the persistence of Na+ conductance inactivation

Which of the following is an advantage that intracellular recordings have over extracellular recordings?

They can record synaptic and receptor potentials.