Studying the Brain

Question 1

Scientists have taken shots at theorizing the function of the brain for any years now. What was Rene Descartes’s theory about the brain?

Answer 1

He theorized that the pineal gland was in fact responsible for the soul of the body. The soul allows thoughts and guides our actions. Of course he was wrong as the pineal gland is responsible for sleep (melatonin)

Question 2

Describe the challenges of studying the brain only through an autopsy.

Answer 2

There are many cons to this method of study (which was seen early on) as it gave no knowledge of the functions of the brain, it meant the study was a long wait game, and oftentimes patients outlived doctors. It also meant that the person could have obtained many different traumas during an expanded lifetime, leading to inconclusive results

Question 3

Through the study of patients who have undergone trauma, what were some conclusions that modern scientists were able to draw on that are similar to phrenologists?

Answer 3

Discovery of Cerebral Localization occurred in modern observation. This phenomenon tells us that specific parts of the brain controls specific actions, thoughts, and even personality. Phrenologists had the same theory in which each region of the brain was devoted to specific tasks, but the particular details of it were completely wrong.

Question 4

Describe the challenges of studying the brain through patients of trauma.

Answer 4

This led to uncontrolled damages to many regions, which led to inconclusive results

Question 5

Paul Broca was historically, one unique example of successful studying of the brain through observation of trauma patients and autopsy. What did he discover among his many patients?

Answer 5

He discovered that people with damage to the left frontal lobe suffered from the inability to speak despite all intact pathways in speech. Therefore this region has become known as Broca’s area and people dx with this injury/dysfunction are dx with Broca’s aphasia.

Question 6

What are ablation studies? What are the results you can achieve from them?

Answer 6

These are experiment studies where you intentionally destroy brain tissues to make lesions and then observe the behavior of the animal. Based on the study, the missing function of the animal is then associated with the destruction of the brain tissue

Question 7

With surgical lesions, what are a few methods within this type of lesion. What are the cons of performing this method?

Answer 7

Surgical removal and Surgical aspiration. Both are very invasive to the animal and surgical aspiration can only be achieved with superficial structures of the brain.

Question 8

What are radio frequency lesions? What are the cons of using this method?

Answer 8

Radio frequency lesions are is a surgically implanted wire to the brain structure of interest. The process begins when you pass a high frequency through to the tip to destroy the tissue. Though it is very effective in targeting the structure of interest, it also destroys anything surrounding it such as passing axons, leading may lead to inconclusive results

Question 9

Wanting to precisely knock out the primary motor cortex in the mouse in front of you, you have decided to choose neurochemical lesions. What type should you choose?

Answer 9

Excitotoxin should be injected into the lobe. This chemical binds to glutamate receptors (Glutamate is released by most of the CNS including the primary motor cortex) which will cause an influx of calcium into the cell. The neurons will become over excited and eventually die knocking out the primary motor cortex

Question 10

How does the mechanism of oxidopamine function in our role in deeper understanding of Parkinson’s disease?

Answer 10

Oxidopamine is a neurochemical that specifically destroys dopaminergic and noradrenergic neurons (therefore neurons that release DA and NE respectively) once it is uptaked with the ntsr from the synapse into the cell. Destroying these cells allow the creates symptoms of Parkinson’s disease, thus enhancing our knowledge further

Question 11

If you want to temporarily cause the basal ganglia to be dormant in order to test a theory, what method would you use to achieve this?

Answer 11

Neurochemical lesion muscimol. This chemical temporarily binds to GABA neurons (aka the main function of the basal ganglia) and prevents them from functioning

Question 12

There are many methods to conduct an ablation experiment. Name a few.

Answer 12

Radio Frequency lesion, neurochemical lesions, surgical lesions, and cortical cooling (Cryogenic Blockade)

Question 13

How is methods of cortical cooling similar to muscimol?

Answer 13

Both are methods of temporary cortical lesions. Other than that, both are very different from one another. Cortical cooling AKA cryogenic blockade is a surgical implant of a cryoloop in between the skull and the brain. Fluid is poured into the loop to cause temporary dysfunction whereas muscimol is a neurochemical lesion in which it binds to GABA producing neurons to have a temporary dysfunction

Question 14

In analyzing methodologies used to study the brain in real time, how can you divide these methodologies for simplicity?

Answer 14

They can be divided into structural images, functional videos/images, or both structure and functional

Question 15

Compare and contrast an MRI and CAT scan.

Answer 15

Both produce and image of the brain and its structures. A CT/CAT/computerized axial tomography scan is the utilization of XR. An MRI/magnetic resonance imaging utilizes a magnetic field and radio waves to produce a more detailed image.

Question 16

True or False: An MRI produces a more detailed image than a CT scan.

Answer 16

True. An MRI is much more detailed as it captures frequencies of atoms whereas XR captures emission of light from regions of structures

Question 17

You’re manually producing an MRI of your patient. After you have lined the atoms in the magnetic field, what needs to occur next. What should your end result be and why?

Answer 17

A radio wave needs to disrupt the alignment of the atoms. After the disruption, the atoms will attempt to align with the magnetic field again and when they do so, they emit a signal captured by the machine.

Question 18

Compare and contrast different types of methodologies for measuring brain function that you need to know for the MCAT.

Answer 18

Electroencephalography (EEG) and Magnetoencephalography (MEG) are visual recordings of brain function in real time. Both allow localization of brain activity but MEG does a much better job at capturing specific details. EEGs are more popular and are used more often in clinical settings due to the portability and noninvasive procedures. MEGs, however, require special shielding of testers.

Question 19

Much like MRI, how is a MEG better at capturing details in comparison to an EEG.

Answer 19

Magnetoencephalography (MEG) utilizes magnetic fields to produce electrical currents in the brain and are measured through SQUIDs.
Note: Magnetic fields = MEG and MRI

Question 20

What can an EEG tell us about a pt?

Answer 20

Their state of consciousness, seizures, and activity especially in tasks

Question 21

It is a common practice to utilize both function and structural imagings when studying your patient’s brain. What methodologies fall under this category? How are they different from one another?

Answer 21

Functional Magnetic Resonance Imaging (FMRI) and Positron Emission Tomography (PET scans) are types of functional and structural imagings. FMRI involves the use of a MRI machine and measuring the oxygen levels of the blood in the brain to determine activity. PET scans utilizes a PET scan with another form of structural imaging to determine activity after the brain has been injected with radioactive glucose.

Question 22

How can glucose and oxygen levels determine activity of the brain? How is this relevant in studying the brain? Which process is more accurate?

Answer 22

Activity of the cells lead to a depletion of both resources and therefore an increase of glucose and oxygen consumption in certain regions imply an increase in activity. Both are utilized in studying the brain, where oxygen is assessed by a FMRI and glucose is assessed by a PET scan. PET/glucose consumption is more accurate as you are able to assess direct flow of glucose, where FMRI/O2 is determining the O2 to deO2 levels in the blood.

Question 23

What is one saying you can utilize to remember glia cells?

Answer 23

Neural Glia Cells “Glue” things together. They act as supporters of the nervous system

Question 24

Differentiate the correct usage of Neurons from Nerve cells and Neural Cells.

Answer 24

Neural Cells refers to cells in the CNS and have two categories of neurons and glia cells. Nerve cells are all other cells of the PNS and encompases both neuronal and glial cells of the PNS. The terms nerve cells and neurons are used interchangeably today because nerve cells is an old terminology used to describe neurons.

Question 25

Nerve cells in the PNS derive from … Neurons in the CNS derive from …

A. Neuroblasts, Neural Crest
B. Neural Crest, Neural Stem Cells
C. Neural Stem Cell, Neuroblasts
D. Neuralblasts, Neural Stem Cells

Answer 25

B. Neural Crest, Neural Stem Cells. Neural stem cells become neural blasts to differentiate into neurons. Only Neuroblasts can become neurons, while the neural stem cells can become anything in the CNS.

Question 26

Both the neural stem and and neuroblast arise early in development from …

A. Rhombencephalon
B. Endoderm
C. Telencephalon
D. Ectoderm

Answer 26

D. Ectoderm. While they both come from the same developmental structure, they specialize into very different things: Neural stem cells => Neurons in the CNS and Neuroblast => Nerve cells in the PNS

Question 27

Name some of the less commonly found glia cells in the body

Answer 27

Satellite, olfactory and sheathing cells

Question 28

What is the purpose of glial cells?

Answer 28

They act like support cells to the nerve cells/neurons. This increases effectiveness and functionality

Question 29

Describe the development of microglias. Why is it helpful to understand its development?

Answer 29

Understanding the development allows comprehension of its function in the brain. Microglias, much like macrophages, specialize in the bone marrow. Microglias differentiate from monocytes and travel up the body to the brain where they function in immunity much like the macrophages.

Question 30

Neuronal cells are the units transmitting signals in a pathway to and from the brain. Contrast non-neuronal cells.

Answer 30

Glias, or neuroglias are non-neuronal cells in the nervous system (CNS and PNS) that produce no electrical impulses. There are 4 main types you have to know: Astrocytes, Microglial, Ependymal, and Oligodendrocytes.

Mnemonic: Glia cells function in Obscuring, Macrophage, set Apart, and CSF => Oligodendrocytes, Microglia, Astrocytes, Ependymal Cells

Question 31

Both Oligodendrocytes and Schwann Cells have the same function.
How do you differentiate between the two?

Answer 31

COPS => CNS - Olgiodendrocytes and PNS - Schwann

Both function in producing myelin sheaths around a neuron.

Question 32

You order an MRI for your patient who suffered some trauma after falling from a stairwell under the influence. He is a reported chronic methamphetamine user. What are your expectations of the blood brain barrier and the cells producing the BBB? What are your concerns if your suspicions are correct?

Answer 32

Psychostimulants such as methamphetamine and MDMA, produce blood brain barriers degeneration. Therefore, you should expect inflammation of the astrocytes producing the BBB. If inflammation is present in the image, you should order a CSF culture. BBB acts as a filter against harmful molecules and infections, therefore a vulnerable BBB increases susceptibility to bacteria and viral infections of the brain. (NHI and Biomedcentral)

Question 33

You are studying a new virus that has the ability to bypass the blood brain barrier. Does this ultimately lead to an infection once the microbe crosses the membrane?

Answer 33

Not necessarily. The brain has many lines of defense. One is the use of microglias as macrophages in which they consume and digest harmful things through a process called phagocytosis.

Question 34

Describe the importance of an ependymal cell in the brain.

Answer 34

They create and regulate Cerebral Spinal Fluid which is important in maintaining an electrolytic environment and serves as a nutrient source to neuronal and non-neuronal cells.

Question 35

Sometimes nerve cells are seen synapsing onto capillaries. What purpose would this hold?

Answer 35

This is often seen with autonomic nerve cells synapsing onto capillaries to deliver hormones to the bloodstream quickly and efficiently. Though astrocytes does synapse to the blood vessels, these glial cells don’t deliver neurotransmitter, but simply acts like a transport system

Question 36

Describe the development of neurons in the central nervous system.

Answer 36

These neurons start as neural stem cells, which differentiate into neuroblasts. The Neuroblasts migrate to the brain (its final destination) and develop further here. The neuroblast further develops and sends its extensions guided by the growth cones at the top to the target cells (Unipolar cells). From there it can further become bipolar cells or multipolar cells.

Question 37

What is the purpose of growth cones? Where are they seen in the body?

Answer 37

Growth cones sit at the tips of the extensions (pre-axons) and they respond to environmental cues until they reach the target cell of the neurons.

Question 38

Much like the CNS neurons, how is the development of neurons of the PNS similar? How is it different?

Answer 38

Both of the cells develop from the other cells of the ectoderm. However, the origin cell type and the migrating cell type for nerves in the PNS are the neural crests. Neurons in the CNS’s original cell are neural stem cells and the migrating cell types are the neuroblast.

Question 39

Compare and contrast unipolar cells and bipolar cells from pseudounipolar cells.

Answer 39

Pseudounipolar cells have a that resembles both a unipolar cell and a bipolar cell. Unipolar because it has one axon with no other dendrites and bipolar because despite the lack of dendrites, they are able to receive information through their axons.

Question 40

How are pseudounipolar cells able to convey signals without an axon hillock?

Answer 40

At the axon terminal where the axons are synapsing onto other cells, they have a similar system that exists an initial segment/trigger zone in which has a certain threshold in order for action potentials.

Question 41

Identify the different structures of a pseudounipolar neuron

Answer 41

One axon is called the peripheral axon and the one after the peripheral axon reaches the soma and extends to the spinal cord is called the central axon. The peripheral axon functions much similarly to a dendrite where it receives information from the peripheral

Question 42

What determines how excitable the neuron is to input?

Answer 42

The resting membrane potential

Question 43

Observing a newly discovered organism, you notice that the nervous system’s cells receive input directly at the cell body. Perhaps this was mislabeled, you conclude. As you dive into literature, what should you expect to find?

Answer 43

Somas of neurons can receive input from axons as well. This is just not commonly seen in many organisms. These cells are originally labeled correctly

Question 44

You are observing a dendrite receive signals from a neighboring cell under a microscope. To your surprise, the signal does not create an action potential! What is the purpose of this signal then?

Answer 44

It attributes to raising the membrane potential away from the rest (these are known as graded potentials) These potentials are short in duration and small in size, therefore they can only travel for short distances.

Question 45

Thinking about what to have for lunch, induces neurons to rapid actively in your prefrontal cortex. What has occurred within the cell to allow and action potential to fire?

Answer 45

In order for an action potential to occur, the neuron needs to receive enough graded potential inputs to overcome the threshold of the axon hillock.

Question 46

You are watching the effects of a psychoactive drug on a serotonergic neuron and see that the release of the neurotransmitter, serotonin is released in a temporal pattern into the synapse. What is the cause of this?

Answer 46

This temporal pattern (therefore a timely pattern) is a result of a temporal pattern of firing action potential down the axon. The faster the action potential travels down the axon, the faster the ntsr is released into the synapse.

Question 47

Put the following statements in order describing neuron function starting with neuron at resting membrane potential with neuron at resting membrane potential

I. Information fired down an axon
II. Membrane potential at trigger zone crosses threshold potential
III. Soma receives excitatory/inhibitory information via dendrites
IV. Release of molecules via neurotransmitters

A. III>II>I>IV
B. III>I>II>IV
C. IV>II>I>III
D. IV>I>II>III

Answer 47

A. III>II>I>IV

Question 48

The resting membrane potential of most neurons are at … and the threshold for most neurons are at …

Answer 48

-70mV and -50mV

Question 49

Briefly outline the travel of a signal from signal to synapse

Answer 49

(1) Graded potentials travel down dendrites to the soma
(2) Soma passes the electric signal to the axon hillock
(3) With enough graded potential, the threshold of -50 mV is overcomed and an action potential starts to propagate
(4) Axon passes signal down through an action potential
(5) Signal reaches the axon terminals and causes vesicles to pour ntsr into the synapse
(6) Ntsr binds to the receptors of the following cell.

Question 50

Your patient is here for a visit today. She complains about feeling lethargic, has a headache, as well as has trouble concentrating on her studies at home. She does admit that she is trying this new keto diet out. How does this affect the neurons’ energy source?

Answer 50

Glucose is the main energy component for neurons. As the neurons are unable to store this energy source as glycogen within it, the neuron depends on the bloodstream for energy and waste disposal. However, with limitations of carbohydrates through consumption, her neurons have less energy to function.

Question 51

Insulin causes receptors in all cells in the body to increase their uptake of glucose except which cells? Why might this be an evolutionary advantage?

Answer 51

All cells respond to insulin except for neurons’s facilitative transporter proteins. Neurons need constant energy in order to function well at all times and to wait for insulin levels to rise (seen after meal consumption) would prove to be harmful to a neuron.

Question 52

Looking at a neuroimaging of your patient’s spinal cord, you come to find a big scar formed there. You do more research and find that he is a former football player who had a serious tackle that took him out of the field for one year. What has created these scars found on his spinal cord. Where else can these signs of healing also occur?

Answer 52

This scar has many names - Glial Scar AKA Gliosis AKA astrogliosis AKA astrocytosis AKA Reactive Astrocytosis. When the central nervous system (both in the spinal cord and the brain) experiences an injury, glial cells called astrocytes migrate to the area of injury and surround the area. They then undergo a process called hypertrophy where they increase in size and become much denser. This not only blocks off of the site of injury in order to prevent further damage to the CNS, but it also performs a similar scaffold function as well. [Note: The glial scar performs similarly to a scaffold function, which acts to support the for neurons and other glias of the CNS]

Question 53

In the case of your student on the keto diet, how can you rest assured that her CNS will remain in tip top shape even though she is not consuming as much carbs as she used to?

Answer 53

The glia cell, astrocytes support her nutritionally. They are able to monitor the extracellular fluid and release lactate (a form of energy) into the ECM because they are able to store some glycogen away. When the concentrations of glucose are low, and the ketosis process in the body has not occurred, these glial cells are able to rapidly convert glycogen to glucose. [Note they also sample the ion concentration and can either intake or release ions to maintain the precise concentrations]

Question 54

Assessing your patients neuroimaging further, you find that his physicians had previously missed some scarring seen in the blood brain barrier. What glial cells were damaged with injury to the BBB? What could be the result of this damage?

Answer 54

Astrocytes contribute to creating the BBB. The role of the BBB is to physically prevent large molecules from entering the CNS. However with damage to this, harmful molecules, viruses, bacteria, etc could have entered the brain.

Question 55

True or False: The blood brain barrier is seen primarily in the brain to protect the brain

Answer 55

False, it is seen throughout the spinal cord as well.

Question 56

As a patient consumes methamphetamine, the large amounts of dopamine are flushed out of the neurons into the synapse. This action allows the indv to feel the euphoria and increase in CNS and bodily functions. However, after some time these feelings and physiological experiences fade. Describe the relationship of astrocytes in this manner.

Answer 56

Astrocytes have projections everywhere within the CNS. Astrocytes send their end foots (processes at the end of projections) help remove ntsr from the synapse. They are important in clearing synapses to allow communication again.

Question 57

Assess what microglia means in laying. How does this help explain what these cells do?

Answer 57

Micro - small, glia - glue, therefore small glue. They are named so because they appear smaller in size to other glial cells. [note: glial cells are considered as the glue of the central nervous system as they support the viability of neurons]

Question 58

Unlike the other glial cells, where is the original of the microglial cells from? What functions are hinted by this?

Answer 58

Microglial cells derive from circulating monocytes from the bone marrow and they enter the CNS to mature and function. Therefore these cells are from the mesoderm rather than from the the ectoderm (like other glial cells). Because they originate from cells essential to immune function, this explains why microglias are essential in inflammation in the CNS and have the ability to macrophage as well as antigen present

Question 59

Contrast the resting phase from the active phase of microglias in structure.

Answer 59

During the resting phase, microglias are small in appear with long projections. During the active phase of a microglia, the cells are huge in size with no projections.

Question 60

What does the microglia cell commit to in performing during its resting phase?

Answer 60

During the resting phase, microglial cells sample the interstitial for signs of inflammation or injury. They also have the ability to consume foreign substances they encounter. If either consumption or detection of signs of injury/infection occurs, the microglia changes from rest to active by retracting their processes and growing in size.

Question 61

Once in the active state, how does the functions of the microglia change?

Answer 61

The active microglia takes on phagocytosis, increasing inflammation (through antigen presentation), and secretion of cytotoxins to kill the foreign substances.

Question 62

You’re assessing a CSF sample of your patient and come across a reactive oxygen species, a cytotoxin. What are you suspecting has occurred within your patient?

Answer 62

A foreign substance has entered the CNS and a microglia has responded to this infection by releasing this cytotoxin in attempt of subduing it. [note: cytotoxin can be released at any time of the process, as a microglia is very flexible in its process]

Question 63

You’re listening to Stephanie talk about how in her class she learned how the CNS defends itself from infections. “When a resting microglial cell comes into counter with a fungi, it consumes it and then releases cytotoxins.” Is her explanation of the sequence of events correct?

Answer 63

Yes, this is not absolute however. Microglias are very flexible in how they handle signs of injury and infection, so the order of events are dependent entirely on the required response at hand

Question 64

True or false: Microglias can activate inflammation, but not start.

Answer 64

False, it does both. It can activate further inflammation through antigen presentation (This allows immune cells to detect the signal and promote a bigger response) and it can begin inflammation by releasing inflammatory mediators (hindawi.com) which leads to an inflammatory response

Question 65

Ependyma is Greek for covering. With this in mind, how does this describe what ependymal cells do in the CNS?

Answer 65

The ependymal cells form a one cell layer covering that separates the CSF from the interstitial fluid.

Question 66

Describe the physical locations of the CSF compared to the extracellular matrix.

Answer 66

The CSF is the outer fluid separated by the ependymal cells and blood vessels. The ECM or the interstitial fluid is the fluid between all the cells of the brain and spinal cord

Question 67

Contrast the surface of the ependymal cell facing the cerebral spinal fluid to the border of the cell facing the brain.

Answer 67

The border of the ependymal cell facing the CSF consists of microvilli (this increases the surface area) and cilia which plays a role in keeping the CSF in motion

Question 68

Compared the blood brain barrier, how is the ependymal cell layer different?

Answer 68

The BBB is composed of the astrocyte end feet and blood vessels, while the ependymal cell layer is a single layer of cell. This single layer does act like a barrier, however it is very leaky in contrast to the BBB.

Question 69

How does modern medicine take advantage of the idea that the ependymal layer is very leaky?

Answer 69

Modern medicine allows sample collecting of the CSF. This collection allows us to understand what it is happening in the CNS because the interstitial fluid leaks.

Question 70

The following are functions of the ependymal cell except:
A Secretion of CSF
B Motion of CSF
C Barrier creation between the brain and skull
D. Barrier creation between the brain and spinal fluid

Answer 70

C. Barrier creation between the brain and skull. This barrier is the blood brain barrier on the most outer layer. Whereas the D. is the layer deep to the brain. (no need to know anatomy) The CSF flows through channels deep within the brain connecting to the spinal cord. All other answers are correct.

Question 71

There are many capillaries seen in the brain. What phenomenon occurs at capillaries next to the ependymal cells to allow medical intervention?

Answer 71

These capillaries allow leakage of the interstitial fluid from deep into the CSF, which makes assessment of CSF samples accurate and true to what is occurring in the CNS.

Question 72

Choose the incorrect definition
A. 1 Oligodendrocyte - 1 myelin sheath
B. 1 Schwann cell - 1 myelin sheath
C. 1 Schwann cell - many myelin sheath 
D. 1 Oligodendrocyte - many myelin sheath

Answer 72

C. 1 Schwann cell - 1 myelin sheath. 1 Oligodendrocyte has the ability to produce many myelin sheath while 1 schwann cell can only myelinate a single neuron’s axon. Therefore everything else is a possibility, however, a schwann cell is unable to produce many myelin sheaths

Question 73

Contrast the embryology of Schwann Cells from Central Nervous System

Answer 73

[Note: Embryology, the study of cellular division and differentiation of the embryo.] Schwann cells derive from neural crest cells while glial cells of the CNS (except for microglial cells) derive from neural stem cells - therefore one derives from the ectoderm while the other from the endoderm respectively.

Question 74

In studying a new species in the central nervous system. You come to find a neuron with a strange axon. This neuron has a myelinated axon, however, the myelin appears to be a cell wrapped around the process. What are some things that are odd about this finding? What should you do next to solve this mystery?

Answer 74

Because it is found in the CNS, the first conclusion would be the myelin is produced by oligodendrocytes or similar to it. However, identification of each myelin sheath as a whole cell wrapped around the axon hints at this cell to be one similar to Schwann cells. You should look at the embryology next as both of these myelin producing cells originate from different points of development. (ectoderm - Schwann and endoderm - Oligodendrocytes

Question 75

How are scientists sure that a Schwann cell wraps itself entirely around the segments of and axon?

Answer 75

Upon looking at the cross section of the axon, you see thin layers of lipid membrane enveloping the axon and on the surface, you can identify the soma with a nucleus (the nucleus of the Schwann cell)

Question 76

Mnemonic to remember Oligodendrocytes and Schwann cells

Answer 76

COPS - CNS/Oligodendrocytes - PNS/Schwann Cells

Question 77

Which of the following lesion studies can be a temporary change in the brain?
. Tissue Removal
II. Cryogenic Blockade
III. Neurochemical Lesions

(A) III only
(B) III and I only
(C) II and III
(D) I, II, and III

Answer 77

(C) II and III. Both Cryogenic Blockades and Neurochemical Lesions can cause a temporary change in the brain for scientist to study the brain.

Question 78

Between EEG & MEG, one has a better resolution, but also requires a lot of set up and a separate room, so it’s usually not used as much. Which one is that?

Answer 78

MEG uses SQUIDS, which has a better resolution than EEG, but it also requires a lot of set up and a separate room. For this reason, EEG are used more often

Question 79

True or False? While neurons are located all over the CNS and PNS, the specific types of Glial Cells are only found in either the CNS or PNS

Answer 79

True. Neurons are located throughout the CNS and PNS. The specific types of Glial cells are specific to either the CNS or PNS.