Anatomy

Question 1

Central nervous system (CNS)

Answer 1

Brain + spinal cord

Question 2

Peripheral nervous system (PNS)

Answer 2

connects the brain and spinal cord to the rest of the body

Question 3

Somatic nervous system

Answer 3

(part of PNS)
voluntary muscles + sensory signals
•	(spinal and cranial nerves)
•	afferent nerves from skin etc
•	efferent nerves to muscles etc
•	consists of the axons conveying messages from the sense organs to the CNS and from the CNS to the muscles

Question 4

autonomic nervous system (ANS)

Answer 4

part of PNS
controls the heart, intestines, and other organs - the "non controllable parts". The autonomic nervous system has some of its cell bodies within the brain or spinal cord and some in clusters along the sides of the spinal cord.
has parasympathetic (vegetative states) and sympathetic (fight/flight) subdivisions

Question 5

Parasympathetic nervous system

Answer 5

part of ANS

 Axons usually release acethychline (slowing down NT)
 The parasympathetic nervous system, sometimes called the “rest and digest” system, facilitates vegetative, nonemergency responses. The term para means “beside” or “related to,” and parasympathetic activities are related to, and generally the opposite of, sympathetic activities. (if sympathetic increases heart rate, parasympathetic decreases it)
 The parasympathetic nervous system is also known as the craniosacral system because it consists of the cranial nerves and nerves from the sacral spinal cord
 Parasympathetic ganglia are not arranged in a chain near the spinal cord. Rather, long preganglionic axons extend from the spinal cord to parasympathetic ganglia close to each internal organ. Shorter postganglionic fibers then extend from the parasympathetic ganglia into the organs themselves. Because the parasympathetic ganglia are not linked to one another, they act more independently than the sympathetic ganglia do.

Question 6

Sympathetic nervous system

Answer 6

 fight/flight – mostly uses norepinephrine NT. (a few, such as those onto the sweat glands, use acetylcholine.)
 The axons/cells very much act ”in sync”
 sympathetic nervous system, a network of nerves that prepare the organs for a burst of vigorous activity, consists of chains of ganglia just to the left and right of the spinal cord’s central regions (the thoracic and lumbar areas). These ganglia have connections back and forth with the spinal cord. Sympathetic axons prepare system for fight/flight.

Question 7

Afferent information

Answer 7

comes into the CNS (incoming information)

• A- ADMIT

Question 8

Efferent information

Answer 8

leaves the CNS (outgoing information).

• E-EXIT

Question 9

Rostral

Answer 9

towards nose

Question 10

Caudal

Answer 10

towards tail

Question 11

Spinal cord

Answer 11

• The spinal cord is the part of the CNS within the spinal column.
• Communicates with the sense organs and muscles (except those in the head) – ADMIT senses, EXIT muscle commands
• Enter through dorsal root (ADMIT)
• EXIT through ventral root.
• The cord is a segmented structure, and each segment has on both the left and right sides a sensory nerve and a motor nerve
• Cell bodies of the sensory neurons are in clusters of neurons outside the spinal cord—the dorsal root ganglia (ganglion = a cluster of neurons outside CNS)
• Cell bodies of the motor neurons are inside the spinal cord
• Entering dorsal roots carry sensory information and exiting ventral roots carry motor information

Question 12

Dorsal root ganglia

Answer 12

Cell bodies of the sensory neurons are in clusters of neurons outside the spinal cord = dorsal root ganglia
- • Entering dorsal roots carry sensory information

Question 13

Where does sensory info ADMIT and where does motor info EXIT in spinal cord?

Answer 13

Entering DORSAL roots carry sensory information and exiting VENTRAL roots carry motor information.

Neuronal cell body MEDIALLY

We have both on left and right side, we have a sensory and motor nerve.
• Sensory nerve sends info INTO spinal cord (Travels up cord to brain) – AFFERENT nerve. –the cell bodies are called dorsal root ganglion because towards back. (OBS! A nerve and a ganglion is not the same thing – nerves are axons, ganglion are cell bodies)
• Motor nerve = conveys motor commands to muscle – EFFERENT nerve - VENTRAL
•

Question 14

What are the major divisions of the brain?

Answer 14

Major divisions are similar across species (during embryonic development)
1. Forebrain (Prosencephalon) (sense of smell (in adult fish/lizard)
• Diencephalon (“between brain”) =Thalamus, Hypothalamus
• Telencephalon (“end brain”) =Cerebral Cortex, Hippocampus, Basal Ganglia
2. Midbrain (Mesencephalon) – vision and hearing
• Tectum, tegmentum, superior colliculus, inferior colliculus, substantia nigra
3. Hindbrain (Rhombencephalon) – movement and balance – posterior section of brain
• Medulla (oblongata), pons, cerebellum

Question 15

Hindbrain (Rhombencephalon)

Answer 15

Evolutionarily the oldest part – most inferior portion
• Consists of the:
• Medulla (most inferior)
• Pons (anterior to medulla)
• Cerebellum (posterior)
Inferior portion of the brain
Hindbrain structures, the midbrain, and other central structures of the brain combine and make up the brain stem
Hindbrain important for controlling involuntary movements.

Question 16

Medulla

Answer 16

• Located just above the spinal cord
• Responsible for vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing
• the head and the organs connect to the medulla and adjacent areas by 12 pairs of cranial nerves (just like nerves in spinal cord connect the limbs to CNS)

Question 17

Cranial nerves

Answer 17

• Allow the medulla to control sensations from the head, muscle movements in the head, and many parasympathetic outputs
• 12 pairs of cranial nerves, one of each on the right and left side, innervating brain stem.

Question 18

Pons

Answer 18

• Lies on each side of the medulla (ventral and anterior)
• The term pons is Latin for “bridge”
• Axons from each half of the brain cross to the opposite side of the spinal cord (left hemisphere controls muscles on right side)
This is were the cerebellum is connected!

Question 19

Cerebellum

Answer 19

• Structure located in the posterior hindbrain with many deep folds
• Helps regulate motor movement, balance, and coordination (but cerebellum still poorly understood)
• Also important for shifting attention between auditory and visual stimuli
• People with cerebellum damage = problems doing these things.
• The cerebellum is also critical for certain types of learning and conditioning
• May do quite a bit more
• Cool fact: has majority of neurons (approx 69 billion)! But takes up only 10% of volume.

Question 20

Midbrain (Mesencephalon)

Answer 20

• Contains the following structures
• Tectum: roof of the midbrain
• Superior colliculus and inferior colliculus: processes sensory information + orienting head towards sensory input  the inferior colliculus for hearing and the superior
• colliculus for vision. + The swellings on each side of the tectum are the superior colliculus and the inferior colliculus
• Tegmentum: contains nuclei for cranial nerves and part of the reticular formation (important for sleep/wake cycles) – right under tectum.
• Substantia nigra: gives rise to dopamine- pathway for movement readiness for movement

Question 21

Tectum

Answer 21

“roof of the midbrain”

Question 22

Superior colliculus and inferior colliculus

Answer 22

processes sensory information + orienting head towards sensory input
the inferior colliculus for hearing
the superior colliculus for vision.
The swellings on each side of the tectum are the superior colliculus and the inferior colliculus

Question 23

Tegmentum

Answer 23

contains nuclei for cranial nerves and part of the reticular formation (important for sleep/wake cycles)

right under tectum

Question 24

Substantia nigra

Answer 24

gives rise to dopamine- pathway for movement readiness – becomes clear when we look at parkinson’s
• Parkinson’s Disease = death of dopamine neurons in this structure = when they die, the individual starts to experience movement disorders, e.g. tremors, rigidity, slowness of movement, postural instability = hallmark symptoms

Possibly also functions in learning, drug addiction, emotion

Question 25

Forebrain (Prosencephalon)

Answer 25

• Diencephalon (“between brain”) = Thalamus, Hypothalamus
• Telencephalon (“end brain”) =Cerebral Cortex, Hippocampus, Basal Ganglia
• The most anterior and prominent part of the mammalian brain, with two cerebral hemispheres
• Consists of the outer cortex and subcortical regions (thalamus, hypothalamus, Basal ganglia, Basal Forebrain, Hippocampus)
• Outer portion is known as the “cerebral cortex”
• Each side receives sensory information and controls motor movement from the opposite (contralateral) side of the body

Question 26

Limbic System

Answer 26

Interlinked structures that form a border around the brainstem.

Olfactory bulb (smell sense), hypothalamus (motivational behaviors, eating, drinking, sexual activity), hippocampus (memory), amygdala (emotions especially fear), and cingulate gyrus of the cerebral cortex

Question 27

Thalamus

Answer 27

relay station from the sensory organs (to the important cortical areas responding to that info, depending on which sensory info), except olfactory info (which goes from the olfactory receptors to the olfactory bulbs and then directly to the cerebral cortex.)
• Thalamus resembles two small avocados joined side by side, one in the left hemisphere and one in the right
• Typically specific nuclei in thalamus receives specific sensory input, and sends it on to specific cortical structures (eg.g. vision = LGN + occipital lobe)

Question 28

Hypothalamus (+pituitary gland)

Answer 28

Hypothalamus conveys messages to the pituitary gland to alter the release of hormones (hypothalamus is located beneath thalamus) – associated with behavior (especially motivational behaviors). Hypothalamus = a small area near the base of the brain just ventral to the thalamus
• Pituitary gland: (endocrine) hormone-producing gland found at the base of the hypothalamus

Question 29

Basal ganglia

Answer 29

It is a group of subcortical structures lateral to the thalamus. includes 3 major structures: caudate nucleus, the putamen, and the globus pallidus.
• Associated with planning of motor movement, and with aspects of memory and emotional expression
• Also associated with attention, planning, learning, and other cognitive functions

Question 30

Basal Forebrain

Answer 30

nucleus basalis = receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex. It is one of the structures on the ventral surface of the forebrain. + key part of the brain’s system for arousal, wakefulness, and attention

Question 31

Hippocampus

Answer 31

• A large structure located between the thalamus and cerebral cortex – complex structure, C-shape – embedded between thalamus and cerebral forebrain
• Toward the posterior portion of the forebrain
• Critical for certain types of memory, especially memories for individual events + role in spatial info (e.g. knowing where you are, and where you’re going)

Question 32

Ventricles

Answer 32

• Ventricles = Four fluid-filled cavities within the brain’s central canal – large one on each side = lateral ventricle - contains CSF

Question 33

Cerebrospinal fluid (CSF)

Answer 33

a clear fluid found in the brain and spinal cord – Cells called the choroid plexus along the walls of the four ventricles produce cerebrospinal fluid (CSF).

• Provides “cushioning” for the brain + provides buoyancy. (helps support the weight of the brain)
• Reservoir of hormones and nutrition for the brain and spinal cord

Question 34

choroid plexus

Answer 34

Cells along the walls of the four ventricles that produce cerebrospinal fluid (CSF).

Question 35

hydrocephalus

Answer 35

Abnormal amount/build-up of CSF: If normal flow of CSF through ventricles and brain is blocked = hydrocephalus. Can cause loss of consciousness, and brain damage. Neurosurgeon would put in shunt to drain the fluid to relieve the pressure.

Question 36

Meninges

Answer 36

• Membranes that surround the brain and spinal cord
• Contain pain receptors (actual brain tissue doesn’t have pain receptors)
• Meningitis—inflammation of the meninges—is painful - Bacterial or viral infection
• Swollen blood vessels in the meninges are the cause of migraine headaches
Pia mater = inner
arachnoid = middle
dura mater = outer

Question 37

Cerebral cortex

Answer 37

• The most prominent part of the mammalian brain
• The cells on the outer surface of the cerebral cortex are gray matter, and their axons extending inward are white matter
• Consists of the cellular layers on the outer surface of the cerebral hemispheres
• Divided into two halves
• Joined by two bundles of axons called the corpus callosum and the anterior commissure
• More highly developed in humans than other species
• Gryi (s. gyrus) – folded surface (ridges) - overfladerne
• Sulci (s. sulcus) – grooves – folderne
If we compare mammalian species, we see differences in the size of the brain and size of the cerebral cortex and the degree of folding.  primates—monkeys, apes, and humans—have a larger cerebral cortex, more folding, and more neurons per unit of volume (interestingly, cerebellum occupies pretty constant amont of space across apecies, approx 10-14 %)

Question 38

Gyri

Answer 38

= the outward folds

Question 39

Sulci

Answer 39

= the “grooves”

Question 40

Laminae

Answer 40

= layers of cerebral cortex

• Contains up to six distinct laminae (layers) that are parallel to the surface of the cortex and separated from each other by layers of fibers
• Cells of the cortex are also divided into columns that lie perpendicular to the laminae – cells within a column has similar properties (e.g. responding to a dot of light in same visual field)
• laminae vary in thickness and prominence from one part of the cortex to another, and a given lamina may be absent from certain areas.
• Layer 4 is relatively thick in sensory cortex, but thin in motor cortex = layers can differ between areas. Has abundance of afferent sensory info from thalamus connect to layer 4. 5 (and 6) are thick in motor cortex, but thin in sensory cortex – has abundance of efferent motor info in layer 5 makes up cortical spinal tract (important for movement) and send signal to spinal cord. Layer 6 connects to other cortical areas. = thickness depends on where you are!

Question 41

Columns

Answer 41

Cells of the cortex are also divided into columns that lie perpendicular to the laminae – cells within a column has similar properties (e.g. responding to a dot of light in same visual field) - columns can cross different laminae.

Question 42

Occipital lobe

Answer 42

• Located at the posterior (caudal) end of the cortex
• Known as the striate cortex or the primary visual cortex
• Highly responsible for visual input
• Damage can result in cortical blindness (partial or complete loss of vision due to damage in specific area – the eye is healthy, and transmission is happening well, but the visual info can’t be further processed into meaningful visual parts (e.g. color, objects, faces))
• In short, the eyes provide the stimulus, and the visual cortex provides the experience.

Question 43

Parietal lobe

Answer 43

• Contains the postcentral gyrus (“primary somatosensory cortex”)
• Posterior to central fissure (deep valley, deeper than a sulcus) at posterior gyrus
• Primary target for touch sensations and information from muscle-stretch receptors and joint receptors
• Essential for spatial information as well as numerical information
Organized as a “sensory homunculus” = maps sub-regions of the cortical postcentral gyrus to certain parts of the body.

Question 44

Temporal lobe

Answer 44

• Lateral portion of each hemisphere
• Target for auditory information and essential for processing spoken language
• Responsible for complex aspects of vision (e.g. face recognition), including movement and some emotional and motivational behaviors
• Klüver-Bucy syndrome associated with temporal lobe damage – very rare cerebral, neurological damage  excessive oral tendency (putting everything in your mouth) (+hypermetamorphisis), need to explore everything, emotional changes, extreme sexual behavior

Question 45

Klüver-Bucy syndrome

Answer 45

Disorder associated with temporal lobe damage – very rare cerebral, neurological damage  excessive oral tendency (putting everything in your mouth) (+hypermetamorphisis), need to explore everything, emotional changes, extreme sexual behavior

Question 46

Frontal lobe

Answer 46

• Precentral gyrus (primary motor cortex): anterior to central fissure
• control of motor movement
• Separate areas are responsible for different parts of the body, mostly on the contralateral (opposite) side but also with slight control of the ipsilateral (same) side. Organized as “motor homonculus” - specific body parts map on to specific parts of precentral gyrus.
• Prefrontal cortex: anterior to precentral gyrus
• Integration of sensory information (from all other areas of cortex)
• Abstract thinking and planning (higher functions)
• Ability to remember recent events and information (“working memory”)
• Injury = problems evaluating ongoing behavior + organizing and planning
• Typically to have 3 major portions:
• The posterior portion is associated mostly with movement.
• The middle zone pertains to working memory, cognitive control, and emotional reactions.
• The anterior zone of the prefrontal cortex is important for making decisions, evaluating which of several courses of action is likely to achieve the best outcome.

Question 47

Prefrontal lobotomy

Answer 47

• Disconnection of the prefrontal cortex from the rest of the brain
• In the 1940s and 1950s, about 40,000 performed – treatment for psychiatric disorders like schizophrenia.
• Patients left with apathy, lack of ability to plan, memory disorders and lack of emotional expression

Question 48

binding problem

Answer 48

The question of how various brain areas produce a perception of a single object

Question 49

How do various brain areas produce a perception

of a single object?

Answer 49

Sensory binding of two stimuli as coming from a single object occurs if you perceive two sensations as happening at the same time and in approximately the
same place. - “rubber hand illusion” demonstrates this!

Question 50

Ablation

Answer 50

removal of a brain area (typically done using surgery)

Question 51

Lesion

Answer 51

damage to a brain area

An electric lesion is a crude technique that damages
the axons passing through as well as the neurons
in the area itself. Researchers use this method
less often today than in the past. Instead, they might
inject a chemical that kills neurons, or disables
them temporarily, without harming the passing axons.
They can also inject a chemical that disables
a particular type of synapse. Another option is the
gene-knockout approach that directs a mutation to
a gene that regulates one type of cell, transmitter, or receptor

Question 52

TMS (transcranial magnetic stimulation)

Answer 52

Application of an intense magnetic field to a portion of the scalp to temporarily deactivate neurons below the magnet –> we can look at resulting behavior
• Used as treatment of depression symptoms (typically when other treatments not working) – repetitive TMS (constant magnetic pulses) = stimulates nerve cells in particular regions associated with mood control (frontal lobe structures) – this is NOT electric convulsive therapy!!!

Question 53

Optogenetics

Answer 53

= using light to control a limited population of neurons.
o 3 steps:
o discover or invent a protein that responds to light by producing an electrical current
o develop viruses that insert one of these proteins into a certain type of, or part of, a neuron.
o develop very thin optical fibers that can shine just the right amount of light onto neurons in a narrowly targeted brain area.
o  investigator can control the excitation or inhibition of one type of neuron in a small brain area with millisecond accuracy

Question 54

Electroencephalograph (EEG)

Answer 54

records electrical activity produced by various brain regions, at scalp level - good temporal bad spatial resolution.

• e.g. used to look at brain activity patterns, e.g. during sleeping states (or brain dead people = only time when no activity at all)
• EEG has a very noise signal = need for repetition!

Question 55

Evoked Potentials (EPs)/Event-Related Potentials (ERPs)

Answer 55

part of EEG = activity in response to a stimulus.
• Largely the graded potentials on dendrites that a sensory stimulus triggers

To counter noise effects (EEG signal is noisy), the stimulus is presented repeatedly, and the recorded responses are averaged

Question 56

Magnetoencephalograph (MEG)

Answer 56

similar to EEG but measures faint magnetic fields generated by brain activity instead – 1 ms accuracy = great temporal resolution, and much better spatial as well (magnetic activity “diffuses” more easily/accurately across brain than electrical activity = better spatial because we can easilier “guess” where activity came from)

Question 57

Computed Tomography (CT scan)

Answer 57

X-ray beams are passed through the brain at many different angles, creating many different images. = STRUCTURAL image of brain.

Question 58

Magnetic resonance imaging (MRI)

Answer 58

Structural imaging
good spatial (smaller than 1 mm), bad temporal resolution
•	3D brain image created by passing a strong magnetic field through the brain, followed by a radio wave, measuring the time it takes for hydrogen atoms to spin back to their original position (by the energy they emit)
•	Different tissues = different amount of hydrogen.
•	MRI = more detail than CT (CT quicker (why used in emergencies) and cheaper)

Question 59

Positron emission tomography - PET

Answer 59

• Imaging technique that detects changes in blood flow by measuring changes in the uptake of (radioactive) compounds such as oxygen or glucose
• Used to analyze the metabolic activity of neurons
• Radioactive molecules are injected into the bloodstream (e.g. glucose infused with radioactive atom) – active areas (involved in e.g. a specific task) use more blood –> more radioactive labels to that area
• High resolution

Question 60

Subtractive method

Answer 60

Control task and experimental task –> subtract control activity from experimental activity = activity related to specific task!
Typically used in functional mimaging (PET + fMRI), also ERP.

Question 61

Functional Magnetic Resonance Imaging (fMRI)

Answer 61

• Newer than PET, now more widely used  safe (no injections or radiation) and less expensive than PET
• When human brain activity increases, the increase in oxygen produced by increased blood flow exceeds the tissue’s need for oxygen.
• The amount of oxygen in an activated brain area increases.
• Changes in the oxygen content of the blood alter the magnetic properties of the water in the blood  this is what the MRI scanner detects
• fMRI allows for good spatial resolution of the brain activity’s source.
• Because changes in blood flow take as long as one-third of a second, the temporal resolution of fMRI is not as precise as that of EEG recordings and ERPs.