Download Preview Sample 2

CHAPTER 2
The Anatomy and Evolution of the Nervous
System
LECTURE OUTLINE
I.
Anatomical Directions and Planes of Section (pp. 27-29)
PowerPoint Slides 2_2, 2_3; Illustrations on Slides 2_4, 2_5
A.
Anatomical directions help us locate structures in the nervous system.
Common directional terms must be established before undertaking a description of the
nervous system. The anatomical directional terms may become confusing due to a 90degree bend in the neuraxis of humans. Comparing the use of the terms between a fourlegged animal and a human is a very useful tool to minimize confusion. (pp. 27-28)
** Note: In both the first and second editions, I presented the anatomical terms in the
traditional ways we see in psychology. Now that more neuroscientists from other disciplines
are teaching the introductory biological psychology course, I think it’s time to standardize
the use of these terms. If you are not comfortable with this change, stick with the
presentation in the text. If you want to standardize with the rest of the neurosciences, use the
formulation below. This helps resolve student questions about why we have two sets of
terms. In a nutshell, the rostral-caudal-dorsal-ventral set “moves” relative to the neuraxis,
but the anterior-posterior-superior-inferior set does not. The rostral-caudal-dorsal-ventral set
rotates at the junction of the midbrain and the diencephalon. Please point out to students that
this change affects Figure 2.1 on p. 28 of their textbooks.
You can think of the anterior-posterior set naming the walls, floor, and ceiling of a room,
whereas the rostral-caudal set applies to the animal in the room, as in this image
To obtain a full-color version of this image for adding to a PowerPoint, please email me at
[email protected]
The Anatomy and Evolution of the Nervous System
15
*See the Supplemental Teaching Strategies and Tools section: Active Learning: Drawing
Neuroanatomy.
1.
Rostral structures are located toward the head within the body region or the
front of the skull within the head region.
2.
Caudal structures are located toward the tail (feet in humans) within the body
region or the rear of the skull within head region.
3.
Dorsal structures are located toward the back within the body region or the top
of the skull within the head region.
4.
Ventral structures are located toward the belly within the body region or the
bottom of the skull within the head region.
5.
In humans, the dorsal parts of our brain form a 90-degree angle with the dorsal
parts of the spinal cord.
6. Anterior structures are in front of the animal, which means the forehead and belly
of a human. In other words, looking at the human spinal cord, anterior and ventral
are equivalent.
7. Posterior structures are in back of the animal, which means the back of the head
and the back of a human. In other words, looking at the human spinal cord,
posterior and dorsal are equivalent.
8. Superior structures are located at the top of the animal, which means the top of
the head in humans. Looking at the human spinal cord, the thoracic division is
both superior and rostral to the lumbar division.
9. Inferior structures are located at the bottom of the animal. In the human spinal
cord, the lumbar division is both inferior and posterior to the thoracic division.
10. Ipsilateral structures are on the same side of the midline, and contralateral
structures are on opposite sides of the midline.
11. Structures near the midline are medial, and structures away from the midline are
lateral.
12. In limbs, proximal structures are closer to the body center, and distal structures
are farther away.
B.
Anatomists make particular cuts or sections in the nervous system in order to view the
structures in two rather than three dimensions. (pp. 28-29)
Discovering Biological Psychology animation brain_structures.swf (This animation
also includes segments on ventricles, hindbrain, midbrain, and forebrain and can be
stopped and restarted accordingly.)
16
1.
Coronal or frontal sections divide the brain from front to back in a vertically cut
plane as if from ear to ear. (Mnemonic: Think of a woman wearing a tiara—
coronal means crown)
2.
Sagittal sections are parallel to the midline and give us a “side” view of the brain
in a vertically cut plane as if from the front to back of the head. A special sagittal
Chapter 2
section cut direction on the midline of the brain is called a midsagittal section.
This is a common view used to describe the corpus callosum, the brainstem and
midbrain structures, and the ventricle system. (Mnemonic: Sagittarius is usually
depicted as a man getting ready to shoot an arrow from a bow, seen from the
side)
3.
II.
Horizontal / axial sections divide the brain from top to bottom in a plane that is
parallel to the floor in a human standing upright.
Protecting and Supplying the Nervous System (pp. 29-32)
PowerPoint Slide 2_6
A.
The Meninges (pp. 29-30)
1.
Three layers of meninges protect the central nervous system: the dura mater,
the arachnoid, and the pia mater.
2.
Only the dura and pia mater layers are present in the peripheral nervous system.
Illustration on Slide 2_7
Clicker Question #1
B.
The Cerebrospinal Fluid circulates through the four ventricles, the central canal of
the spinal cord, and the subarachnoid space, floating and cushioning the central
nervous system. Although the ventricular system curves and folds as the brain
matures, it starts out as the simple interior of the neural tube. Students often find it
simpler to understand the flow of CSF in this simpler form. (pp. 30-31)
Illustration on Slide 2_8
Film Clip #1: The Ventricles
Film Clip #2: Inserting a CSF Shunt
The Cerebrospinal Fluid (CSF) can be thought of as an ultra-filtered version of the
plasma found in circulating blood. The CSF is generated by the choroid plexus
primarily in the lateral ventricles and it flows in a pattern from the left and right lateral
ventricles into the medial third ventricle through the narrow cerebral aqueduct of the
midbrain into the fourth ventricle between the brainstem and the cerebellum and
The Anatomy and Evolution of the Nervous System
17
finally into the central canal of the spinal cord and the surrounding subarachnoid space
where it is absorbed back into the blood supply. A primary function of the CSF is to
protect the brain through floating the brain rather than attaching it to the skull.
*See the Lecture Enrichment section for additional information about the daily
production of CSF, and see the Supplemental Teaching Strategies and Tools section
for demonstrations of the effects of daily CSF turnover and CSF buoyancy.
Hydrocephalus is the condition resulting from a blockage of CSF flow through the
central nervous system. The blockages usually occur at the narrow passages in the
ventricle system such as the cerebral aqueduct. These blockages are commonly
associated with development, tumor growth, or swelling of the brain due to trauma.
*See the Lecture Enrichment and Supplemental Reading sections for additional
information about a new clinical diagnosis, Normal Pressure Hydrocephalus (NPH),
that affects the elderly and mimics Alzheimer’s Disease and Parkinson’s Disease but
is easily alleviated.
C.
The Blood Supply: The brain is supplied with blood through the carotid and vertebral
arteries. (pp. 31-32)
Illustration on Slide 2_9
Clicker Question #2
The neurons of the central nervous system use large amounts of energy and thus
require a constant supply of oxygen and glucose among other nutrients. In fact, the
average adult brain represents only 5% of the total body weight; however, the brain
uses more than 20% of the body’s total cardiac output. There is no storage of oxygen
or glucose within the central nervous system and so an uninterrupted supply is critical.
Significant neural death occurs within 3 minutes of the central nervous system not
receiving any new blood supply. In the event of a cardiac arrest, effective and
immediate CPR first-aid helps keep oxygenated blood flowing to the central nervous
system to prevent brain damage.
The carotid arteries have very large diameters whereas the upstream cerebral arteries
and capillaries become very small in diameter. Debris, such as blood clots or plaque
deposits, which become dislodged and pass through the carotid artery but block the
smaller cerebral arteries or capillaries are common causes of strokes (discussed in
detail in Chapter 15). The effect of a stroke maybe localized to particular regions of
the brain depending on whether the posterior, middle, or anterior cerebral arteries are
affected.
*See the Lecture Enrichment section for additional information about blood
circulation within the central nervous system.
III. The Central Nervous System (pp. 33-47)
PowerPoint Slides 2_11, 2_16; Illustration on Slide 2_10
A.
The Spinal Cord (pp. 33-35)
Illustration on Slide 2_12
Clicker Question #3
Film Clip #3: Brain-Computer Interfaces for Paralyzed Individuals
18
Chapter 2
1.
2.
The spinal cord may be divided into cervical, thoracic, lumbar, and sacral
segments.
The spinal cord segments are named according to vertebral bones surrounding
the spinal cord. The incoming afferent sensory nerves and outgoing efferent
motor nerves exit the vertebral column between each vertebral bone resulting in
31 discrete nerve segments. The area that is innervated by each of the 31 spinal
nerves is called a dermatome. The motor cortex and somatosensory cortex
respectively located in the frontal and parietal lobes are organized in a medial to
lateral fashion by ascending dermatome from the toes to the head.
In addition to carrying messages to and from the brain, the spinal cord provides a
variety of protective and motor reflexes.
The withdrawal reflex is a commonly understood reflex that involves only three
neurons. The afferent sensory neuron enters the dorsal spinal cord and forms a
synapse in the gray matter of the dorsal horn with both an ascending sensory
neuron that travels to the brain in the dorsal column white matter and an
interneuron. In turn, the interneuron along with descending motor neurons
traveling in the ventral white matter form a synapse with the outgoing ventral
motor neuron to complete the reflex circuit. The level of incoming sensory
signals determines activation of the interneuron with lower levels of input
ascending to the somatosensory cortex without activating the reflex circuit.
*See Supplemental Teaching Strategy 1: Active Learning: Drawing
Neuroanatomy.
B.
The Hindbrain (pp. 35-37)
Illustration on Slide 2_13; Table of Brainstem Structures on Slide 2_14
Film Clip #4: Human Brain Tutorial on Brainstem and Diencephalon
In terms of evolution, the development of brain regions follows the order of
hindbrain then midbrain then forebrain, with the cerebral hemispheres being the
most recent brain structure to develop. Similarly, functions associated with each brain
region begin with the most basic life sustaining functions and progress to more
complex functions through the ascending brain regions.
1.
The hindbrain consists of the medulla, pons, and cerebellum. The medulla is
also known as the myelencephalon, and together, the pons and cerebellum make
up the metencephalon.
In addition to containing nuclei representing the first central nervous system
synaptic processing of incoming somatosensory, vestibular, auditory, and taste
neural signals, the medulla and pons also contain several nuclei that control life
sustaining functions such as heart rate, respiration, and the vomiting reflex.
*See the Lecture Enrichment section for additional information about the
hindbrain nuclei.
In addition to its known role in coordinating neural signals from the sensory and
motor systems, the cerebellum also likely plays a role in cognitive functions such
as attention, learning, and memory. The specific role of the cerebellum in
advanced cognitive functioning has yet to be fully characterized.
The Anatomy and Evolution of the Nervous System
19
*See the Supplemental Reading section for additional information about the
well-documented role of the lateral interpositus nucleus of the cerebellum in the
ability of rabbits to learn the classical conditioning of an eye blink in response to
an auditory tone (see Chapter 12).
2.
Running through the medulla and pons at the midline is the reticular formation,
which helps control arousal.
Due to the associated life sustaining functions, damage to hindbrain and the
reticular formation in particular is likely to cause coma or death. Trauma to the
brain often produces a swelling response that can apply pressure on the hindbrain
inducing a transient coma until the pressure is relieved.
C.
The Midbrain: The midbrain, also known as the mesencephalon, contains the
remaining section of the reticular formation, the periaqueductal gray, the red
nucleus, the superior colliculi, the inferior colliculi, and the substantia nigra.
The periaqueductal gray is involved in gate control theory of natural pain management
as part of the descending pathway responsible for the release of opioid peptides in
response to incoming pain signals in the spinal cord. (pp. 37-38)
Illustration on Slide 2_15
Clicker Question #4
The red nucleus is involved in the motor output pathway and is the efferent nucleus
receiving information from the lateral interpositus nucleus of the cerebellum to
produce the conditioned eyelid response to an auditory tone in the example of classical
conditioning learning discussed in the Supplemental Reading section.
The substantia nigra is a midbrain nucleus specifically targeted during the neural
degeneration of Parkinson’s disease. The loss of the pathway from the substantia nigra
to the basal ganglia produces the primary motor symptoms of Parkinson’s disease.
The superior and inferior colliculi are respectively involved in the ability to orientate
the body toward visual and auditory stimuli. Animals that rely on visual and auditory
tracking to detect prey have proportionally larger superior or inferior colliculi.
D.
The Forebrain (pp. 38-46)
1.
The diencephalon contains the thalamus and hypothalamus.
Illustration on Slide 2_17
Film Clip #5: Horizontal Section of Human Brain at the Roof of the Third
Ventricle
A common misconception is that the thalamus serves a “relay” nucleus with little
or no processing of incoming sensory information. The thalamus also
participates in states of consciousness and arousal (see Chapter 11) and learning
and memory (see Chapter 12).
*See the Lecture Enrichment section for additional information regarding the
role of the processing in the thalamus.
The hypothalamus is best described as the central regulator of the internal
physiological state of our body including the homeostatic functions of circadian
20
Chapter 2
rhythms, thermoregulation, reproduction, and ingestive behavior. The
hypothalamus also controls the release of hormones from the pituitary gland
and regulates the activation of the autonomic nervous system.
2.
The telencephalon contains the cerebral cortex, basal ganglia, and limbic system
structures.
The basal ganglia consist of the anterior and medially located caudate nucleus,
the putamen and globus pallidus located anterior and lateral to the thalamus,
and the subthalamic nucleus located below the thalamus. The basal ganglia
border the lateral ventricles and degeneration of the basal ganglia, such as that
occurring in Huntington’s disease, is often identified through brain scans
revealing enlarged lateral ventricles. Pressure on the basal ganglion from CSF in
the lateral ventricles produces the shuffling gait symptom of normal pressure
hydrocephalus.
Illustration on Slide 2_19
Film Clip #6: The Basal Ganglia
The limbic system consists of medial subcortical structures collectively involved
in memory or the interpretation and expression of emotion. Some limbic
structures such as the amygdala and septal area appear to have specific
emotional functions (fear, rage, attack, and aggression), while other areas such as
the cingulate cortex have broader functional roles. The anterior cingulate cortex
(ACC) also participates in decision-making, error-detection, anticipation of
reward, and empathy. The posterior cingulate cortex (PCC) participates in eye
movements, spatial orientation, and memory, and is one of the first structures
affected by Alzheimer’s disease. The hippocampus, parahippocampal gyrus,
mammillary bodies, and fornix form tightly connects circuits involved in the
formation of declarative memories (see Chapter 12). Emotion, the sense of smell,
and the formation and recall of memories have strong associations between one
another, thus the olfactory bulbs are often associated as limbic system
structures.
Illustration on Slide 2_20; Table of Limbic Structures on Slide 2_21
Clicker Question #5
Film Clip # 7: Sagittal Section at the Hippocampus
Film Clip #8: Sagittal Section at the Amygdala
3.
The cerebral cortex is made up of six layers that cover the outer surface of the
cerebral hemispheres.
Illustration on Slide 2_23
a)
The “hills” of the cortex are referred to as gyri (plural of gyrus), and the
“valleys” are referred to as sulci (plural of sulcus) or fissures. The extent
of the convolution of the cerebral cortex into gyri and sulci is directly
related to the amount of cortical surface area contained within the skull. As
the skull restricts the available volume for brain matter, the “wrinkling” of
the cortex allows a greater surface area and thus more cortical neurons.
Most cognitive functions are associated with the cerebral cortex and there
The Anatomy and Evolution of the Nervous System
21
is a positive correlation between the degree of cortical convolution and the
cognitive abilities of various species.
Illustration on Slide 2_22
b)
*See the Supplemental Teaching Strategies and Tools section for a
demonstration of the ability of convolutions to increase surface area.
The cerebral cortex is divided into four lobes: the frontal lobe associated
with motivation, personality, emotion, cognitive tasks such as executive
function and judgment, and the motor system; the parietal lobe associated
with somatosensation, association cortex, and advanced visual processing
such as how to correctly respond to a visual stimulus; the temporal lobe
associated with the auditory system, language comprehension, and
association cortex involved with memory storage; and the occipital lobe
which is almost exclusively reserved for processing of visual stimuli.
Illustration on Slide 2_24
c)
The cerebral cortex also can be divided into sensory (somatosensation in
the anterior parietal lobe, audition in the superior temporal lobe, vision in
the occipital lobe, olfaction in the ventral frontal lobe, and gestation in the
insular cortex at the junction of the temporal and parietal lobes), motor
(posterior frontal lobe), or association cortex based on its function. Most
of the sensory areas of the brain are located towards the back (caudal
areas), whereas most of the motor areas of the brain are located rostrally.
d)
The two cerebral hemispheres are connected by the corpus callosum and
the anterior commissure.
Illustration on Slide 2_25
Clicker Question #6
e)
*See the Lecture Enrichment Section for additional information about
correlations between corpus callosum size and handedness.
Some functions, such as language, appear to be localized on one
hemisphere or the other.
While there is good evidence of the lateralization of function for some
specific tasks such as language comprehension and production respectively
in Wernicke’s area of the left temporal lobe and Broca’s area of the left
frontal lobe, the lateralization of other more intricate cognitive functions is
much less clear (see Chapter 13). In general, the right hemisphere reacts
more to negative emotional stimuli (avoidance), whereas the left
hemisphere reacts more to positive stimuli (approach; see Chapter 14).
IV. The Peripheral Nervous System (pp. 47-52)
PowerPoint Slide 2_26
A.
The Cranial Nerves: Twelve pairs of cranial nerves exit the brain and provide sensory
and motor functions to the head and neck. (pp. 47-48)
Illustrated on Slide 2_27
22
Chapter 2
It is often helpful for students to employ a mnemonic device to remember the order
and names of the twelve cranial nerves. A simple summary of the nerves is as follows:
CNI, olfactory nerve, smells; CNII, optic nerve, sees; CNIII, oculomotor nerve,
moves eyes, constricts pupils, accommodates; CNIV, trochlear nerve, moves eyes;
CNV, trigeminal nerve, chews and provides facial sensations; CNVI, abducens
nerve, moves eyes; CNVII, facial nerve, tastes and produces facial expressions;
CNVIII, auditory-vestibular nerve, hears and provides balance / posture sensations;
CNIX, glossopharyngeal nerve, tastes and provides sensory / motor functions of
throat; CNX, vagus nerve, provides input to and sensations from the chest (heart,
liver, digestive tract); CNXI, spinal accessory nerve, moves the head, neck, and
shoulders; CNXII, hypoglossal, moves the tongue. Students might benefit from
mnemonics for remembering these in order: On Old Olympus Towering Tops, a Finn
and German Viewed Some Hops.
B.
The Spinal Nerves (pp. 48-49)
Illustrated on Slide 2_28
C.
1.
Spinal nerves contain dorsal afferent nerve roots and ventral efferent nerve
roots of the somatic nervous system that merge outside the cord to form mixed
nerves. A common pitfall is confusing the afferent and efferent terms. An easy
association is that “a” comes before “e” in the alphabet and often we think of
incoming “afferent” sensory information arriving before an outgoing “efferent”
motor response to that sensation. Another mnemonic is to think of “a” for
“access” and “e” for “exit.”
2.
Efferent nerves are myelinated, whereas afferent nerves may or may not be
myelinated (see Chapters 7 and 8).
The Autonomic Nervous System provides sensory and motor innervation to glands,
organs, and smooth muscle. (pp. 49-52)
PowerPoint Slide 2_29; Illustration on Slide 2_30
Two subcomponents of the autonomic nervous system, the sympathetic and
parasympathetic nervous system, act in opposition to one another with three primary
differentiations: action on target organs, anatomical pathway, and type of
neurotransmitter released.
1.
The sympathetic nervous system operates during times of arousal and prepares
the body for fight-or-flight reactions. The sympathetic nervous system is
connected at the level of the ganglion producing a system known as the
sympathetic chain. This connectivity results in the sympathetic nervous system
being activated simultaneously as a whole unit allowing fast and complete
reactions to an emergency. Norepinephrine is the primary neurotransmitter
released by the sympathetic nervous system to its target organs.
Film Clip #9: Fight or Flight
2.
The parasympathetic nervous system operates during times of rest and
restoration. Unlike the sympathetic nervous system, the parasympathetic neurons
are not connected with individual neural pathways to each target organ. This
allows for differential activation of specific targets in response to particular
needs, such as activation of the digestive system in response to the ingestion of
The Anatomy and Evolution of the Nervous System
23
food. Acetylcholine is the primary neurotransmitter released by the
parasympathetic nervous system to its target organs.
3.
V.
The hypothalamus controls the autonomic nervous system by way of connections
in the midbrain tegmentum.
Evolution of the Human Brain and Nervous System (pp. 53-57)
PowerPoint Slide 2_31
Illustration on Slide 2_32
Why Does This Matter: Is Evolution Still Shaping Human Beings? (p. 53)
A.
Natural Selection and Evolution (pp. 53-54)
1. Natural selection is the process by which favorable traits become more common
in subsequent generations due to organisms’ different reproductive success.
2. Fitness is the likelihood that an organism will reproduce successfully compared
to other members of the same species.
B.
Evolution of the Nervous System (pp. 54-55)
Why Does This Matter: Do Animals Have Minds? (p. 55)
Illustration on Slide 2_33 and Slide 2_34
Film Clip #10: Oldest Fossil Brain
Film Clip #11: Reverse Evolution
1.
The nervous system has been a relatively recent development in the course of
evolution.
2.
Single-cell organisms originated 3.5 billion years ago. Organisms developed
neural nets approximately 700 million years ago, followed by organisms with
ganglia located in a head region approximately 250 million years ago. Human
brains appeared approximately 7 million years ago.
3.
Chordates are the only animals possessing a true spinal cord and brain.
4.
As the brain evolved, it became larger. In particular, the encephalon or cerebral
cortex expanded and due to the capacity limit of the skull, the cerebral cortex
became more convoluted.
*See the Supplemental Reading section for additional information on
comparative neuroanatomy across species.
C.
Evolution of the Human Brain (pp. 55-57)
New Directions: Neuroscientists Search for Self-Awareness in the Brain (p. 58)
Clicker Questions #7 and #8
Film Clip # 12: Human Evolution
Film Clip # 13: Hominid Development
Film Clip #14: Neanderthal DNA Sequenced
24
Chapter 2
Film Clip #15: Brain Evolution
1.
Human beings have experienced very rapid brain growth over the last five
million years, possibly in response to the challenges of using tools, language,
social behavior, and learning to plan for the future.
2.
It is unclear is why such major cultural changes over the last 200,000 years, such
as agriculture, urbanization, and literacy, have not produced additional changes
in brain size.
3.
One explanation of the late of recent changes in brain size is that a ceiling effect
may have been reached where the advantages of further increases in brain size
may be offset by childbirth difficulties and the large amount of resources
required by the nervous system.
LECTURE ENRICHMENT
II. B. – Daily CSF Production
The total CSF volume in an adult is approximately 120 ml and the average daily production of
CSF ranges between 300 to 500 ml resulting in approximately three turnovers per day. The
passages between the lateral ventricles and the third ventricle as well as the cerebral aqueduct are
narrow and have the potential to be restricted by either the growth of a tumor or general swelling
of the brain in response to a traumatic event. Since the CSF is continuously produced restricting
its flow results in an increase of ventricle pressure that can produce brain damage if the pressure
is not relieved by insertion of a shunt to drain the excess CSF. Hydrocephalus is a condition,
typically occurring during development in newborn infants, in which the CSF flow is restricted
and must be relieved through shunt insertion.
II. B. – Normal Pressure Hydrocephalus
Normal pressure hydrocephalus (NPH) is a relatively new clinical diagnosis that typically occurs
in elderly patients and is believed to be related to a decrease in the absorption of CSF by the
arachnoid villi. The symptoms of NPH, dementia, a shuffling gait, and urinary incontinence, are
often misdiagnosed as either Alzheimer’s disease or Parkinson’s disease. Typically, NPH is
diagnosed using a neuroimaging scan of the brain to identify enlarged ventricles due to the CSF
pressure. Insertion of a shunt to relive the CSF pressure immediately alleviates all three
debilitating symptoms. *See the Supplemental Reading List for additional information.
II. C. – Blood Circulation in the Central Nervous System
Blood containing oxygen and nutrients is supplied to the brain through arteries and capillaries
found in the subarachnoid space found between the arachnoid and pia mater layers. Blood
containing waste products pools in the venous sinus cavities between the arachnoid space and
dura before exiting the brain through the veins. A leak in the blood system may produce a pocket
of fluid that depending on its location may be described as a subdural or subarachnoid hematoma.
III. B. 1. – Hindbrain Nuclei
It is important to note that the hindbrain sensory nuclei are not merely “relay” synapses but rather
there is significant processing of the incoming sensory signals in these hindbrain nuclei. Several
of the hindbrain nuclei that control life sustaining functions utilize common neurotransmitters,
The Anatomy and Evolution of the Nervous System
25
such as dopamine, permitting serious side-effects of dopaminergic drugs that are intended to
activate higher cortical centers such as the nucleus accumbens.
III. D. 1. – Processing in the Thalamus
It is well documented that the thalamus plays a critical role in filtering incoming sensory
information based on the amount of attention paid to particular sensations. Furthermore, using the
vision system as an example, there is a divergence of neural signals within the complex
retinotopic organization of neurons in the lateral geniculate nucleus of the thalamus. This
provides both the first central nervous system consolidation of visual fields from both the left and
right retinas as well as a separation of the magnocellular and parvocellular pathways with
approximately 1 million incoming ganglion axons to each ipsilateral thalamus and 1.5 million
projection neurons to the visual cortex in the occipital lobe.
III. D. 3. d) – Corpus Callosum and Handedness
The corpus callosum of individuals that are left-handed appears to be approximately 10% larger
than the corpus callosum of individuals that are right-handed. It is speculated that an increase in
neural transmission from the language areas of the left hemisphere to the motor output of the right
hemisphere may be related to this increase in connectivity.
SUPPLEMENTAL READING LIST
Genes to Cognition
Cold Spring Harbor Laboratory in New York maintains a multimedia-rich site covering
neuroanatomy, genetics, cognition, and clinical disorders. Especially useful for teaching
this chapter is the 3-D interactive brain. The brain can be fully rotated, and underlying
structures can be selected. Retrieved on April 3, 2009 from http://www.g2conline.org/
Gray’s Anatomy
Gray’s Anatomy of the Human Body is a classic anatomy text. Section IX. Neurology features
excellent neuroanatomical descriptions and sketches. This online edition hosted by Yahoo! as an
educational reference source enables users to view and save images for use in lecture instruction.
Retrieved April 3, 2009, from http://education.yahoo.com/reference/gray/
The Cerebellum’s Role in Cognition
New evidence is emerging to support a role of the cerebellum in cognitive functioning. In
particular, the cerebellum has been shown to play a critical role in the ability of rabbits to learn an
association between an eyelid response and an auditory tone through a classical conditioning
paradigm. More information on the role of the cerebellum in this learning process can be found in
the following recent publications:
Learning- and cerebellum-dependent neuronal activity in the lateral pontine nucleus. Bao S, Chen
L, Thompson RF. Behav Neurosci. 2000 Apr;114(2):254-61.
Neuronal activity in the cerebellar interpositus and lateral pontine nuclei during inhibitory
classical conditioning of the eyeblink response. Freeman JH Jr., Nicholson DA. Brain Res. 1999
Jul 3;833(2):225-33.
26
Chapter 2
Reversible lesions of the red nucleus during acquisition and retention of a classically conditioned
behavior in rabbits. Clark RE, Lavond DG. Behav Neurosci. 1993 Apr;107(2):264-70.
Normal Pressure Hydrocephalus (NPH)
eMedicine Reference Entry for Normal Pressure Hydrocephalus. Author: Arif Davli. Contains
background, pathophysiology, symptoms, and treatment information for the relatively new
clinical diagnosis of normal pressure hydrocephalus in the elderly. Retrieved April 3, 2009, from
http://www.emedicine.com/neuro/topic277.htm
Saved from Senility. 60 Minutes Broadcast on October 7, 2004 featuring case studies of NPH.
Videotape Information 1-800-848-3256. Retrieved April 3, 2009, from
http://www.cbsnews.com/stories/2004/10/04/60II/main647205.shtml
The Visible Human Project®
The National Library of Medicine’s Visible Human Project® provides serial sections through not
only the nervous system but the entire body of a man and woman allowing visualization of the
central and peripheral nervous system components in relation to non-neural physiological
structures.
Retrieved April 3, 2009, from http://www.nlm.nih.gov/research/visible/visible_human.html
The Human Brain: An Introduction to Its Functional Anatomy
The Human Brain describes the structure and function of the brain and nervous system focusing
on neurobiology and neurophysiology. The latest edition includes clinical content, many images
depicting neurological disorders, and expanded sections on higher cortical functions such as
learning and memory. Publication information: John Nolte, The Human Brain: An Introduction to
Its Functional Anatomy. 5th edition, C.V. Mosby, ISBN: 0323013201.
Other useful references include:
Haines, D.E. (2008). Neuroanatomy: An Atlas of Structures, Sections, and Systems (7th Ed.).
Lippincott
Nolte, J., & Angevine, J. (2007). The Human Brain in Photographs and Diagrams. Mosby.
Neuroanatomy Through Clinical Cases
Neuroanatomy through Clinical Cases uses over 100 actual clinical case studies and high-quality
radiological images as the basis for teaching functional neuroanatomy. The clinical cases and
images in this text would provide excellent examples in the classroom instruction of
neuroanatomy. Each chapter is separated into a section of background neuroanatomical
information followed by related clinical cases. The clinical cases are presented as a narrative of
the patient’s symptom development and subsequent neurological examination. Publication
information: Hal Blumenfeld, Neuroanatomy through Clinical Cases. Sinauer Associates, ISBN:
0878930604.
Comparative Neuroanatomy Across Species
This website provides good visual and descriptive information about comparative neuroanatomy
across multiple species. Retrieved April 3, 2009, from:
http://serendip.brynmawr.edu/bb/kinser/Home1.html
The Anatomy and Evolution of the Nervous System
27
SUPPLEMENTAL TEACHING STRATEGIES AND TOOLS
Active Learning: Drawing Neuroanatomy
Encouraging students to physically draw the components of the nervous system engages the
students in an active learning process that will produce longer lasting memories than mere
observation of text or lecture diagrams. A common stumbling block is the students’ belief that
they cannot draw very well. This anxiety can be alleviated by the instructor producing their own
drawings during the lecture, encouraging the students to do likewise, and demonstrating that even
crude or unrefined drawings are still very beneficial in understanding the anatomical terms and
the locations of central nervous system structures. Good opportunities to use active learning
through drawing are presented during instruction of the anatomical directions (especially the
difference between four-legged animals and humans, draw an example for each and label the
anatomical directions in both the head and spine of the human), the lobes of the brain, and the
spinal cord anatomy (draw a cross-section of the spinal cord including the white versus gray
matter and dorsal versus ventral nerves, in addition it can also be beneficial to then draw a spinal
reflex circuit to aid in understanding the relationship between afferent and efferent pathways in
the spinal cord).
In addition, students can be encouraged to use the coloring book feature of the Student Study
Guide. Illustrations from the textbook appear with keys and label lines.
Demonstrating Daily CSF Turnover
For this demonstration you will need the following items: 6 pack of 500 ml bottles of water, 150
ml beaker, 2 L beaker, and 1 tennis ball. At the front of the class set-up the 150 ml beaker inside
of a 2 L glass beaker and remove 3 of the bottles of water from the 6 pack leaving the other 3
bottles of water intact in the 6 pack ring binder. Demonstrate the total volume of the CSF by
pouring enough water to fill the 150 ml beaker. Next, demonstrate the total amount of CSF
produced each day by continuing to empty the 500 ml water bottle into the 150 ml beaker inside
of the 2 L beaker. Finally, demonstrate the effects of hydrocephalus by adding another 1 or 2 500
ml bottles of water to show the amount of CSF and corresponding pressure produced per day in
the event of a blockage of the ventricle system.
Demonstrating Daily CSF Buoyancy
Similar to the reduction in your body weight when you float in a pool, the buoyancy effect of the
CSF reduces the weight of the brain 97% from 1500 grams to 50 grams, the difference between
the weight of four cans of soda versus a tennis ball. For this demonstration you will need the
following items: 3 500 ml bottles of water and 1 tennis ball. During this demonstration, you can
pass the additional 3 bottles of 500 ml water leftover from the above CSF turnover demonstration
(approximate weight 1500 g) and the tennis ball (approximate weight 50 g) around the class as a
demonstration of the reduction in adult brain weight due to the buoyancy effect of CSF.
28
Chapter 2
Demonstrating the Ability of Convolutions to Increase Surface Area
For this demonstration you will need a bowl, several large sheets of paper, and scissors or a
marker pen. To demonstrate the difference in surface area for smooth and convoluted structures
such as the cerebral cortex of various species, first fit a piece of paper to the inside of the bowl in
as smooth a manner as possible. Then, cut off the excess paper or trace the rim of the bowl on the
paper with the marker. The bowl represents the fixed volume of the skull and the paper represents
the amount of cortex for a species with a relatively smooth cerebral cortex. Now, crumble a sheet
of paper to produce small convolutions in the surface and fit as much of the paper around the
inside of the bowl as possible. Then, cut off any excess paper or trace the rim of the bowl on the
paper with the marker. Finally, flatten the convoluted paper and compare to the original surface
area of the smooth paper. This demonstration works best if rehearsed with various size bowls and
pieces of paper prior to use in the classroom.
Sheep Brain Dissections
This online demonstration is especially useful to faculty who have limited lab facilities.
Whether you have sheep brains for students to examine or not, this tutorial covers the
bases. A nice feature allows you to show or hide labels—old (1996) but quite functional.
http://academic.scranton.edu/department/psych/sheep/ A simpler version can be found
here: http://www.hometrainingtools.com/articles/brain-dissection-project.html This
version includes downloadable pdfs for printing and labeling.
This Exploratorium version has some excellent images:
http://www.exploratorium.edu/memory/braindissection/index.html
A nice handout with photographs and clear directions is here:
http://psych.hanover.edu/classes/neuropsychology/Syllabus/Labs/DISSECTION.pdf
Human Brain Tutorial
This nice little site compares MRI images and models of the human brain. You click on a
structure, and a name appears along with a multiple choice question to test your learning.
Retrieved on April 3, 2009 from
http://www.gwc.maricopa.edu/class/bio201/brain/BrainModelMap.htm
FILM CLIP SUGGESTIONS
1) The Ventricles (5:12)
http://www.youtube.com/watch?v=9hI1j4xQ-n8&feature=related
2) Insertion of a CSF Shunt (1:04)
http://www.youtube.com/watch?v=Qmym2iFVNw8&feature=related
3) Brain-Computer Interfaces (Stanford University) (14:11)
Krishna Shenoy is creating "brain-computer interfaces" that will enable paralyzed patients to
control prosthetic arms and computer cursors. In this short talk, Shenoy describes how his team of
Stanford researchers has built a system that achieves typing at 15 words-per-minute, just by
"thinking about it".
http://www.youtube.com/watch?v=I7lmJe_EXEU&feature=PlayList&p=373EE4E8CFA
A2B19&index=0&playnext=1
The Anatomy and Evolution of the Nervous System
29
4) A tutorial on the brainstem and diencephalon using a real human brain (4:40)
http://www.dailymotion.com/video/x5ugwe_neuroanatomy-neuroanatomia_school
5) Horizontal Section of Human Brain at the Roof of the Third Ventricle (4:31)
Various structures in a human brain horizontal slice at the level of the roof of the third ventricle.
Structures include thalamus, caduate, lateral ventricles, fornix, internal capsules and more.
http://www.youtube.com/watch?v=hSOK2_SZLW8&feature=related
6) The Basal Ganglia (5:35)
http://www.youtube.com/watch?v=EluAk9NWOJI
7) Sagittal Section at the Hippocampus (1:56)
Various structures in a human brain sagittal slice at the level of the hippocampus. Structures
include amygdala, caduate, lateral ventricles, hippocampus, internal capsules and more.
http://www.youtube.com/watch?v=MD0XHzsRhLo&feature=related
8) Sagittal Section at the Amygdala (2:11)
Various structures in a human brain sagittal slice at the level of the amygdala. Structures include
amygdala, caduate, lateral ventricles, hippocampus, internal capsules and more.
http://www.youtube.com/watch?v=wQJ1nAY9jxY&feature=related
9) Fight or Flight (3:34)
The role of the amygdala, hypothalamus, and cortex in responding to danger.
http://www.youtube.com/watch?v=RyP8L3qTW9Q&feature=related
10) Oldest Fossil Brain (0:41)
http://www.newscientist.com/projects/misc/video?bcpid=1896802502&bclid=190473293
2&bctid=14612708001
11) Reverse Evolution (1:40)
Scientists have reversed evolution, reconstructing a gene that existed more than 500 million years
ago. The gene controls our ability to smile or frown.
http://www.youtube.com/watch?v=qyJGA_1_v8A&feature=channel
12) Human Evolution (2:14)
http://www.youtube.com/watch?v=ahloeBhlcYk&feature=related
13) Hominid Development
Dikika Research Project
The Discovery
Ape or Human?
What Can We Conclude?
http://www.nature.com/nature/focus/hominiddevelopment/video/index.html
30
Chapter 2
14) Neanderthal DNA Sequenced
Introduction
New Techniques
Analysis
Conclusions
http://www.nature.com/nature/videoarchive/neanderthaldna/
15) Brain Evolution (1:17)
Battles over teaching evolution may be playing out near you. Meanwhile, scientists have new
evidence that our most important organ - the brain- is still evolving.
http://www.youtube.com/watch?v=o5_COfNSu5k&feature=channel
**Note: Lahn’s work is undeniably controversial given its racial implications, so
instructors should research this topic prior to presenting the film. See an interview with
Lahn at SEED, retrieved April 3, 2009, from
http://seedmagazine.com/content/article/seed_interview_bruce_lahn/
His original paper is here: http://www.sciencemag.org/cgi/content/abstract/309/5741/1720
CLICKER QUESTIONS FOR AUDIENCE RESPONSE SYSTEMS
1.
I have had a vaccination for bacterial meningitis.
A. Yes
B. No
Question type: React
2. John’s grandfather had a serious stroke involving his left middle cerebral artery.
Which of the following behaviors are likely to be the most challenging for him now?
A. Seeing the right visual field.
B. Planning behavior and making decisions.
C. Interpreting the facial expressions of other people.
D. Speaking and understanding language.
Question type: Check your learning
3. Daniel damaged his spinal cord at the cervical level in an automobile accident. Which
of the following describes the most likely result of his accident?
A. Daniel’s damage will heal over the course of about six months to a year.
B. Daniel will be a quadriplegic, meaning he will lose the use of arms and legs.
C. Daniel will probably be paralyzed on the right side of his body.
D. Daniel will be a paraplegic, meaning that he will lose the use of his legs, but not
his arms.
Question type: Check your learning
The Anatomy and Evolution of the Nervous System
31
4. The substantia nigra can be found in which of the following divisions of the brain?
A. The myelencephalon
B. The metencephalon
C. The mesencephalon
D. The diencephalon
E. The telencephalon
Question type: Check your learning
5. If you were a physician treating a patient with a tumor pressing on his or her
amygdala, which of the following would you do?
A. Inform the patient that in rare similar cases, irrational violence has occurred.
B. Simply treat the medical condition without discussing the possible behavioral
outcomes.
C. Alert authorities that the patient has a definite risk of irrational violence.
D. Discuss the possibility of irrational violence with the patient’s immediate family
members.
Question type: React
6.
Which of the following is correct?
A. Sensory and motor areas are evenly distributed among the four lobes of the brain.
B. Sensory processing takes place in the right hemisphere, whereas motor processing
takes place in the left.
C. Sensory processing takes place toward the front of the brain, and motor
processing occurs towards the back of the brain.
D. Sensory processing takes place toward the back of the brain, and motor
processing occurs towards the front of the brain.
Question type: Check your learning
7. Human beings, as we know them, developed from earlier species of animals.
A. True
B. False
Question type: React
Note: This is the classic question used in Miller et al.’s work on public opinion worldwide about evolution: Miller, J.D., Scott, E.C., & Okamoto, S. (2006). Science
communication. Public acceptance of evolution. Science, 313, 765-766. Figure 2.3
compares rates of agreement in many different countries.
32
Chapter 2
8. Evolution is still occurring among contemporary humans:
A. True
B. False
Question type: React
The Anatomy and Evolution of the Nervous System
33