Chapter 4- Anatomy Of The Nervous System

Question 1

The anatomy of the nervous system

Answer 1

Neuroanatomy

Question 2

What are the two main divisions of the vertebrate nervous systems called?

Answer 2

The central nervous system CNS and the peripheral nervous system PNS

Question 3

The brain and the spinal cord

Answer 3

Central nervous system CNS

Question 4

Nerves outside the brain and spinal cord

Answer 4

Peripheral nervous system PNS

Question 5

Part of the PNS that consists of the axons conveying messages from the sense organs to the CNS and from the CNS to the muscles

Answer 5

Somatic nervous system

Question 6

Part of the PNS that controls the heart, intestines, and other organs

Answer 6

Autonomic nervous system

Question 7

Located toward the back

Answer 7

Dorsal

Question 8

Toward the stomach

Answer 8

Ventral

In four-legged animals, The top of the brain is dorsal or on the same side as the animals back, and the bottom of the brain is ventral or on the stomach side. The same would be true for you if you got down on your knees and crawled

The dorsal-ventral axis of the human brain is at a right angle to the dorsal-ventral axis of the spinal cord

Question 9

Toward the front end

Answer 9

Anterior

Question 10

Toward the rear end

Answer 10

Posterior

Question 11

Above another part

Answer 11

Superior

Question 12

Below another part

Answer 12

Inferior

Question 13

Toward the side, away from the midline

Answer 13

Lateral

Question 14

Toward the midline, away from the side

Answer 14

Medial

Question 15

Located close or approximate to the point of origin or attachment

Answer 15

Proximal

Question 16

Located more distant from the point of origin or attachment

Answer 16

Distal

Question 17

On the same side of the body. For example, two parts on the left or two on the right

Answer 17

Ipsilateral

Question 18

On the opposite side of the body. For example, one on the left and one on the right

Answer 18

Contralateral

Question 19

A plane that shows brain structures as seen from the front

Answer 19

Coronal plane or frontal plane

Question 20

A plane that shows brain structures as seen from the side

Answer 20

Sagittal plane

Question 21

A plane that shows brain structures as seen from above

Answer 21

Horizontal plane or transverse plane

Question 22

What does dorsal mean, and what is its opposite?

Answer 22

Dorsal means toward the back, away from the stomach side. It’s opposite is ventral

Question 23

What term means toward the side, away from the midline, and what is its opposite?

Answer 23

Lateral; medial

Question 24

If two structures are both on the left side of the body, they are ______ to each other. If one is on the left and the other is on the right, they are ______ to each other

Answer 24

Ipsilateral; contralateral

Question 25

A row or layer of cell bodies separated from other cell bodies by a layer of axons and dendrites

Answer 25

Lamina

Question 26

A set of cells perpendicular to the surface of the cortex, with similar properties

Answer 26

Column

Question 27

A set of axons within the CNS, also known as a projection. If axons extend from cell bodies in structure A to synapses onto B, we say that the fibres “project” from A onto B

Answer 27

Tract

Question 28

A set of axons in the periphery, either from the CNS to a muscle or gland or from a sensory organ to the CNS

Answer 28

Nerves

Question 29

A cluster of neuron cell bodies within the CNS

Answer 29

Nucleus

Question 30

A cluster of neuron cell bodies, usually outside the CNS, as in the sympathetic nervous system

Answer 30

Ganglion

Question 31

A protuberance on the surface of the brain

Answer 31

Gyrus

Question 32

A fold or groove that separates one gyrus from another

Answer 32

Sulcus

Question 33

A long, deep sulcus

Answer 33

Fissure

Question 34

The bulges in the cerebral cortex are called ______. The grooves between them are called _______.

Answer 34

Gyrus; sulcus

Question 35

Part of the CNS; it communicates with all the sense organs and muscles except those of the head. It is a segmented structure, and each segment has on each side a sensory nerve and a motor nerve.

Answer 35

Spinal cord

Question 36

The concept that the entering dorsal roots carry sensory information and the exiting ventral roots carry motor information

Answer 36

Bell-Magendie law

Question 37

Clusters of sensory neurons outside the spinal cord

Answer 37

Dorsal root ganglia

Question 38

Areas of the nervous system that are densely packed with cell bodies and dendrites

Answer 38

Gray matter

Question 39

Area of the nervous system consisting mostly of myelinated axons

Answer 39

White matter

Question 40

In a cross-section through the spinal cord, the H-shaped _____ ______ in the centre of the cord is densely packed with cell bodies and dendrites. The ______ ______ consists mostly of myelinated axon’s

Answer 40

Gray matter; white matter

Question 41

A network of nerves that prepare the organs for vigourous activity

Answer 41

Sympathetic nervous system

Question 42

System of nerves that facilitate vegetative, non-emergency responses by the body’s organs

Answer 42

Parasympathetic nervous system

Question 43

The autonomic nervous system consists of neurons that receive information from and send commands to the heart, intestines, and other organs. What are the two parts of the autonomic nervous system?

Answer 43

Sympathetic nervous system; parasympathetic nervous system

Question 44

Describe the functions, locations, and organization of the sympathetic nervous system

Answer 44

Prepares the organs for vigourous 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 are connected by axons to the spinal cord.

Sympathetic axons prepare the organs for “fight or flight” – increasing breathing and heart rate and decreasing digestive activity.

Because the sympathetic a ganglia are closely linked, they often act as a single system “in sympathy” with one another.
The sweat glands, the adrenal gland’s, the muscles that constrict blood vessels, and the muscles that erect the hairs of the skin have only sympathetic, not parasympathetic, input

Most of the postganglionic synapses of the sympathetic nervous system use norepinephrine, although a few, such as those that control the sweat glands, use acetylcholine

Question 45

Describe the functions, locations, and organization of the parasympathetic nervous system

Answer 45

Facilitates vegetative, non-emergency responses. The term para means “beside” or “related to”, and parasympathetic activities are related to, and generally the opposite of, sympathetic activities
Parasympathetic activity decreases heart rate, increases digestive rate, and in general, conserves energy

Also known as the craniosacral system because it consists of the cranial nerves and nerves from the sacral spinal cord. Unlike the ganglia in the sympathetic system, the parasympathetic ganglia are not arranged in a chain near the spinal cord. Long preganglionic axons extend from the spinal cord to parasympathetic ganglia close to each internal organ. Shorter postganglionic fibres then extend from the parasympathetic ganglia into the organs themselves.
Because the parasympathetic ganglia are not linked to one another, they act more independently then the sympathetic ganglia do.

The parasympathetic nervous system’s postganglionic axons release the neurotransmitter acetylcholine.

Because the two systems, the parasympathetic and sympathetic nervous system’s use different transmitters, certain drugs excite or inhibit one system or the other. For example, over the counter cold remedies exert most of their effects by blocking parasympathetic activity or increasing sympathetic activity that block the action of the sinus fluids which is a parasympathetic response. Sympathetic – increase heart rate

Question 46

Sensory nerves enter which side of the spinal cord, dorsal or ventral?

Answer 46

Dorsal

Question 47

Which functions are controlled by the sympathetic nervous system? Which are controlled by the parasympathetic nervous system?

Answer 47

The sympathetic nervous system prepares the organs for vigourous fight-or-flight activity. The parasympathetic system increases vegetative responses such as digestion.

Question 48

The posterior part of the brain

Answer 48

Hindbrain

Greek root: rhombencephalon

Question 49

What are the three parts of the hindbrain?

Answer 49

The medulla, the pons, and the cerebellum

Question 50

The medulla, pons, midbrain, and central structure of the forebrain

Answer 50

Brainstem

Question 51

Hind brain structure located just above the spinal cord; could be regarded as an enlarged extension of the spinal cord

Answer 51

Medulla

Question 52

What are the functions of the medulla?

Answer 52

Controls vital reflexes including breathing, heart rate, vomiting, salivation, coughing, and sneezing through the cranial nerves, which control sensations from the head, muscle movements in the head, and much of the parasympathetic output to the organs

Question 53

Nerves that control sensations from the head, muscle movements in the head, and much of the parasympathetic output to the organs

Answer 53

Cranial nerves

Some of the cranial nerves include both sensory and motor components, where as others have just one or the other. The receptors and muscles of the head and organs connect to the brain by 12 pairs of cranial nerves, one of each pair on the right side and one on the left. Each cranial nerve originates in a nucleus or cluster of neurons, that integrates the sensory information, regulates the motor output, or both.
The cranial nerve nuclei for nerves V through XII are in the medulla and pons. Those for cranial nerves I through IV are in the midbrain and forebrain

Question 54

Cranial nerve with the function of smell

Answer 54

Olfactory

Question 55

A cranial nerve related to vision

Answer 55

Optic

Question 56

A cranial nerve that controls eye movements and pupil constriction

Answer 56

Oculomotor

Question 57

A cranial nerve that controls eye movement

Answer 57

Trochlear and abducens

Question 58

A cranial nerve responsible for skin sensations from most of the face; control of jaw muscles for chewing and swallowing

Answer 58

Trigeminal

Question 59

A cranial nerve responsible for taste from the anterior two thirds of the tongue; control of facial expressions, crying, salivation, and dilation of the heads blood vessels

Answer 59

Facial

Question 60

A cranial nerve responsible for hearing; equilibrium

Answer 60

Statoacoustic

Question 61

A cranial nerve responsible for taste and other sensations from throat and posterior third of the tongue; control of swallowing, salivation, throat movements during speech

Answer 61

Glossopharyngeal

Question 62

A cranial nerve responsible for sensations from neck and thorax; control of throat, esophagus, and larynx; parasympathetic nerves to stomach, intestines, and other organs

Answer 62

Vagus

Question 63

A cranial nerve responsible for control of neck and shoulder movements

Answer 63

Accessory

Question 64

A cranial nerve responsible for control of muscles of the tongue

Answer 64

Hypoglossal

Question 65

Hindbrain structure that lies anterior and ventral to the medulla

Answer 65

Pons

Question 66

Describe the functions of the pons

Answer 66

Contains nuclei for several cranial nerves. Is Latin for “bridge”, reflecting the fact that in the pons, axons from each half of the brain cross to the opposite side of the spinal cord so that the left hemisphere controls the muscles of the right side of the body and the right hemisphere controls the left side.

The medulla and pons also contain the reticular formation and the raphe system

Question 67

A structure that extends from the medulla into the forebrain; controls motor areas of the spinal cord and selectively increases arousal and attention in various forebrain areas

Answer 67

Reticular formation

Has descending and ascending portions. The descending portion is one of several brain areas that control the motor areas of the spinal cord. The ascending portion sends output to much of the cerebral cortex, selectively increasing arousal and attention in one area or another

Question 68

Brain areas that send axons to much of the forebrain, modifying the brains readiness to respond to stimuli

Answer 68

Raphe system

Question 69

A large hindbrain structure with many deep folds. Long been known for its contributions to the control of movement, balance, and coordination. Also has functions that extend far beyond balance and coordination – people with damage to this area have trouble shifting their attention back-and-forth between auditory and visual stimuli and much difficulty with timing, including sensory timing

Answer 69

Cerebellum

Question 70

Middle part of the brain

Answer 70

Midbrain

Greek root: mesencephalon

In adult mammals it is dwarfed and surrounded by the forebrain

Question 71

What are the major structures in the midbrain?

Answer 71

Tectum, tegmentum, superior colliculus, inferior colliculus, substantia nigra

Question 72

Roof of the midbrain

Answer 72

Tectum

Is the Latin word for roof.

Question 73

Intermediate level of the midbrain

Answer 73

Tegmentum

Latin word for “covering”. Covers several other midbrain structures, although it is covered by the tectum. Includes the nuclei for the third and fourth cranial nerves, parts of the reticular formation, and extensions of the pathways between the forebrain and the spinal cord or hindbrain

Question 74

Swelling on either side of the tectum; important to visual processing

Answer 74

Superior colliculus

Question 75

Swelling on each side of the tectum; important for auditory processing

Answer 75

Inferior colliculus

Question 76

A midbrain structure that gives rise to a pathway releasing dopamine. This pathway facilitates readiness for movement

Answer 76

Substantia nigra

Question 77

Most anterior part of the brain; consists of two cerebral hemispheres

Answer 77

Forebrain

Greek root: prosencephalon

Each hemisphere is organized to receive sensory information, mostly from the contralateral or opposite side of the body, and to control muscles mostly on the contralateral side, by way of axons to the spinal cord and the cranial nerve nuclei

Question 78

What are the major structures of the forebrain?

Answer 78

Thalamus, hypothalamus, cerebral cortex, hippocampus, basal ganglia

Question 79

What is the outer portion of the cerebral hemispheres called?

Answer 79

Cerebral cortex

Latin for “bark” or “shell”

Question 80

Interlinked structures that form a border around the brainstem. Important for motivations and emotions, such as eating, drinking, sexual activity, anxiety, and aggression.

Answer 80

Limbic system

Includes the olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus of the cerebral cortex

Question 81

A pair of structures (left and right) in the centre of the forebrain. Most sensory information goes here first, is processed, and the output is sent to the cerebral cortex. An exception is the old factory information, which progresses from the old factory receptors to the factory bulbs and then directly to the cerebral cortex

Answer 81

Thalamus

Many nuclei of the thalamus receive their input from a sensory system, such as vision, and transmit information to a single area of the cerebral cortex. The cerebral cortex sends information back to the thalamus, prolonging and magnifying certain kinds of input at the expense of others, thereby focussing attention on particular stimuli

Question 82

The thalamus and hypothalamus form the ______, a section distinct from the ________, which is the rest of the forebrain

Answer 82

Diencephalon; telencephalon

Question 83

Small area near the base of the brain, ventral to the thalamus. Has widespread connections with the rest of the forebrain and the midbrain. Contains a number of distinct nuclei. Conveys messages to the pituitary gland, altering its release of hormones

Answer 83

Hypothalamus

Damage to any hypothalamus nucleus leads to abnormalities in motivated behaviors, such as feeding, drinking, temperature regulation, sexual behavior, fighting, or activity level

Question 84

An endocrine gland attached to the base of the hypothalamus. Attached to the base of the hypothalamus buy a stock that contains neurons, blood vessels, and connective tissue. In response to messages from the hypothalamus, synthesizes hormones that the blood carries to organs throughout the body

Answer 84

Pituitary gland

Question 85

A group of subcortical forebrain structures lateral to the thalamus. Includes three major structures: the caudate nucleus, the putamen, and the globus pallidus.
Had subdivisions that exchange information with different parts of the cerebral cortex. Damage to this area impairs movement, as in conditions such as Parkinson’s disease and Huntington’s disease. Also critical for learning and remembering how to do something as opposed to learning factual information or remembering specific events. Also important for attention, language, planning, and other cognitive functions

Answer 85

Basal ganglia

Question 86

A forebrain structure that lies on the ventral surface; receives input from the hypothalamus and basal ganglia; sends axons to areas in the cerebral cortex. These axons release acetylcholine to widespread areas in the cerebral cortex.
A key part of the brain system for arousal, wakefulness, and attention. Patients with Parkinson’s disease and Alzheimer’s have impairments of attention and intellect because of inactivity or deterioration here.

Answer 86

Nucleus basalis

Question 87

A large structure located toward the posterior of the forebrain, between the thalamus and the cerebral cortex. Critical for storing certain kinds of memories, especially memories for individual events

Answer 87

Hippocampus

Latin for “seahorse”

People with hippocampal damage have trouble storing new memories, but they do not lose all the memories they had before the damage occurred

Question 88

A fluid-filled channel in the centre of the spinal cord

Answer 88

Central canal

Question 89

Four fluid-filled cavities within the brain

Answer 89

Ventricles

Question 90

A clear fluid similar to blood plasma produced by choroid plexus in the brain ventricles

Answer 90

Cerebrospinal fluid CSF

CSF feels the ventricles, flowing from the lateral ventricles to the third and fourth ventricles. From the fourth ventricle, some of it flows into the central canal of the spinal cord, but more goes into the narrow spaces between the brain and the thin meninges. In one of those narrow spaces, the subarachnoid space, the blood gradually reabsorbs the CSF.
Cerebrospinal fluid cushions the brain against mechanical shock when the head moves. It also provides buoyancy and helps support the weight of the brain. It also provides a reservoir of hormones and nutrition for the brain and spinal cord.

Question 91

Membranes that surround the brain and spinal cord

Answer 91

Meninges

The meninges have pain receptors – inflammation is painful

Question 92

Of the following, which are in the hindbrain, which in the midbrain, and which in the forebrain: basal ganglia, cerebellum, hippocampus, hypothalamus, medulla, pituitary gland, ponds, substantia nigra, superior and inferior colliculi, tectum, tegmentum, thalamus?

Answer 92

Hindbrain: cerebellum, medulla, and pons.

Midbrain: substantia nigra, superior and inferior colliculi, tectum, and tegmentum.

Forebrain: basal ganglia, hippocampus, hypothalamus, pituitary, and thalamus.

Question 93

Which area is the main source of input to the cerebral cortex?

Answer 93

Thalamus

Question 94

Layers of cells on the outer surface of the cerebral hemisphere of the forebrain

Answer 94

Cerebral cortex

The cells of the cerebral cortex are gray matter, and their axons extending inward are white matter

Question 95

Bundle of axons that connects the two hemispheres of the cerebral cortex

Answer 95

Corpus callosum and anterior commissure

Question 96

Order of mammals that includes monkeys, apes, and humans

Answer 96

Primates

The cerebral cortex constitutes a higher percentage of the brain in primates. As the proportion devoted to the forebrain increases in insectivores and primates, the relative sizes of the midbrain and medulla decrease. The cerebellum occupies a remarkably constant percentage – approximately 13% of any mammalian brain

Question 97

Layer of cell bodies that are parallel to the surface of the cerebral cortex and separated from each other by layers of fibres

Answer 97

Laminae

In humans and most other mammals, the cerebral cortex contains up to six distinct laminae. They vary in thickness and prominence from one part to another, and may be absent from certain areas. Lamina V, which sends long axons to the spinal cord and other distant areas, is thickest in the motor cortex, which has the greatest control of the muscles.
Lamina IV, which receives axons from the various sensory nuclei of the thalamus, is prominent in all the primary sensory areas but absent from the motor cortex

Question 98

Collection of cells having similar properties, arranged perpendicular to the laminae

Answer 98

Columns

For example, if one cell in a column responds to touch on the palm of the left hand, then the other cells in that column do too

Question 99

If several neurons of the visual cortex all respond best when the retina is exposed to horizontal lines of light, then those neurons are probably in the same ______

Answer 99

Column

Question 100

Posterior section of the cerebral cortex. The main target for visual information

Answer 100

Occipital lobe

Question 101

The posterior pole of the occipital lobe is known as the _____ ______ _____ or striate cortex, because of its striped appearance in cross-section.
Destruction of any part of this area causes ______ ______ in the related part of the visual field.

Answer 101

Primary visual cortex; cortical blindness

For example, extensive damage to the striate cortex of the right hemisphere causes blindness in the left visual field.

A person with cortical blindness has normal eyes and pupillary reflexes, but no conscious visual perception and no visual imagery, not even in dreams. People who suffer I damage become blind, but if they have an intact occipital cortex and previous visual experience, they can still imagine visual scenes and can still have visual dreams

Question 102

Section of the cerebral cortex between the occipital lobe and the central sulcus. Responsible for body sensations

Answer 102

Parietal lobe

Monitors all the information about eye, head, and body positions and passes it on to brain areas that control movement. Essential not only for spatial information but also numerical information.

Question 103

One of the deepest grooves in the surface of the cerebral cortex

Answer 103

Central sulcus

Question 104

Area just posterior to the central gyrus; primary receptor site for touch and other body sensations

Answer 104

Postcentral gyrus

Also known as primary somatosensory cortex

Receives sensations from touch receptors, muscle-stretch receptors, and joint receptors.
Includes four bands of cells parallel to the central sulcus. Separate areas along each band receive simultaneous information from different parts of the body. Two of the bands receive mostly light-touch information, one receives deep-pressure information, and one receives a combination of both. In effect, it represents the body four times.

Question 105

The lateral portion of each hemisphere, near the temples. It is the primary cortical target for auditory information.

Answer 105

Temporal lobe

The human temporal lobe – in most cases, the left temporal lobe – is essential for understanding spoken language. Also contributes to complex aspects of vision, including perception of movement and recognition of faces. A tumour here may give rise to elaborate auditory or visual hallucinations.

Question 106

A behavioural disorder caused by temporal lobe damage.
Previously wild and aggressive monkeys fail to display normal fears and anxieties after temporal lobe damage. They put almost anything they find into their mouths and attempt to pick up snakes and lighted matches.

Answer 106

Klüver-Bucy syndrome

Question 107

Section of the cerebral cortex that extends from the central sulcus to the anterior limit of the brain.
Contains the primary motor cortex and the prefrontal cortex.

Answer 107

Frontal lobe

Question 108

Posterior portion of the frontal lobe just anterior to the central sulcus; specialized for fine movement control

Answer 108

Precentral gyrus

Specialized for control of fine movements, such as moving one finger at a time. Separate areas are responsible for different parts of the body, mostly on the contralateral side but also with slight control of the ipsilateral side.

Question 109

Anterior portion of the frontal lobe, which responds mostly to the sensory stimuli that signal the need for a movement

Answer 109

Prefrontal cortex

The dendrites in the pre-frontal cortex have up to 16 times as many dendritic spines as neurons in other cortical areas. As a result, it integrates an enormous amount of information

Question 110

Which lobe of the cerebral cortex includes the primary auditory cortex?

Answer 110

Temporal lobe

Question 111

Which lobe of the cerebral cortex includes the primary somatosensory cortex?

Answer 111

Parietal lobe

Question 112

Which lobe of the cerebral cortex includes the primary visual cortex?

Answer 112

Occipital lobe

Question 113

Which lobe of the cerebral cortex includes the primary motor cortex?

Answer 113

Frontal lobe

Question 114

Surgical disconnection of the prefrontal cortex from the rest of the brain

Answer 114

Prefrontal lobotomy

Consequences included apathy, a loss of the ability to plan and take initiative, memory disorders, distractibility, and a loss of emotional expressions. People with damage here also lost their social inhibitions ignoring the rules of polite, civilized conduct. They often acted impulsively because they failed to calculate adequately the probable outcomes of their behaviours

Question 115

Assignment in which an animal must respond on the basis of a signal that it remembers but that is no longer present

Answer 115

Delayed-response task

People with damage to the prefrontal cortex have trouble with these kinds of tasks, showing problems with a major function of the prefrontal cortex: working memory

Question 116

What are the functions of the prefrontal cortex?

Answer 116

The prefrontal cortex is especially important for working memory, or memory for what is currently happening, and for planning actions based on the context

For example, deciding to answer the phone when it rings based on the context. You would probably answer it in your own home, but not in someone else’s home.

Question 117

Question of how various brain areas produce a perception of a single object

Answer 117

Binding problem or large-scale integration problem

Earlier researchers thought that various kinds of sensory information converged on to what they called the association areas of the cortex. Later research found that the association areas perform advanced processing on a particular sensory system, such as vision or hearing, but few cells combine one sense with another.

Question 118

What is meant by the binding problem, and what is necessary for binding to occur?

Answer 118

The binding problem is the question of how the brain combines activity in different brain areas to produce unified perception and coordination behavior.

Binding requires identifying the location of an object and perceiving sight, sound, and other aspects of a stimulus as being simultaneous. When the site and sound appear to come from the same location at the same time, we bind them as a single experience.
For example, when a skilled ventriloquist makes the dummies mouth move at the same time as his or her own speech, in nearly the same place, you perceive the sound as coming from the dummy

Question 119

What are the 4 categories that most methods of researching the brain fall into?

Answer 119

1. Examine the effects of brain damage
2. Examine the effects of stimulating a brain area
3. Record brain activity during behaviour
4. Correlate brain anatomy with behaviour

Question 120

Removal of a brain area, and generally with a surgical knife

Answer 120

Ablation

However, surgical removal is difficult for tiny structures far below the surface of the brain

Question 121

Damage to a structure

Answer 121

Lesion

Used for tiny structures far below the surface of the brain that ablation cannot reach. Researchers use a stereotaxic instrument to make the lesions.

Question 122

A device for the precise placement of electrodes in the brain

Answer 122

Stereotaxic instrument

By consulting a stereotaxic atlas or map of some species brain, a researcher aims an electrode at the desired position relative to certain landmarks on the skull. Then the researcher anesthetizes the animal, drills a small hole in the skull, inserts the electrode, lowers it to the target, and passes an electrical current just sufficient to damage that area

Question 123

The application of an intense magnetic field to a portion of the scalp, temporarily inactivating neurons below the magnet

Answer 123

Transcranial magnetic stimulation

Allows researchers to study a given individual’s behaviour with the brain area active, then inactive, and then active again

Question 124

What is the difference between a lesion and an ablation?

Answer 124

A lesion is damage to a structure. An ablation is removal of the structure. For example, a blood clot might produce a lesion, whereas surgery could produce an ablation

Question 125

Researchers can insert electrodes to stimulate brain areas in laboratory animals. A new technique _______, enables researchers to turn on Activity in targeted neurons by a device that shines a laser light within the brain

Answer 125

Optogenetics

Question 126

How do the effects of brief, mild magnetic stimulation differ from those of longer, more intense stimulation?

Answer 126

Brief, mild magnetic stimulation on the scalp increases activity in the underlying brain areas, whereas longer, more intense stimulation blocks it

Question 127

Why does electrical or magnetic stimulation of the brain seldom produce complex, meaningful sensations or movements?

Answer 127

Meaningful sensations and movements require a pattern of precisely timed activity in a great many cells, not just a burst of overall activity diffusely in one area

Question 128

A device that records electrical activity of the brain through electrodes attached to the scalp

Answer 128

Electroencephalograph EEG

Question 129

Electrical recordings on the scalp from brain activity in response to a stimulus

Answer 129

Evoked potentials or evoked responses

Question 130

A device that measures the faint magnetic fields generated by brain activity

Answer 130

Magnetoencephalograph MEG

Question 131

Method of mapping activity in a living brain by recording the emission of radioactivity from injected chemicals

Answer 131

Positron-emission tomography PET

Question 132

A modified version of MRI that measures energies based on hemoglobin instead of water; determines the brain areas receiving the greatest supply of blood and using the most oxygen

Answer 132

Functional magnetic resonance imaging fMRI

Generally has replaced PET scan’s because they are less expensive and less risky

Question 133

What does fMRI measure?

Answer 133

It measures changes in blood flow to the brain. It detects an increase in blood flow to a brain area immediately after an increase in brain activity, and it also detects a slightly slower increase in the percentage of hemoglobin lacking oxygen

Question 134

Suppose someone demonstrates that a particular brain area becomes active when people are listening to music. When that area becomes active later, what, if anything, can we conclude?

Answer 134

Without further evidence, we should not draw any conclusion. Perhaps the person is listening to music again, but this area may perform functions other than listening to music. A good test of how well we understand the area would be to find out whether we can use fMRI recordings to guess which type of music someone is hearing or whether they are listening at all

Question 135

Method of visualizing a living brain by injecting a dye into the blood and placing a persons head into a CT scanner; x-rays are passed through the head and recorded by detectors on the opposite side

Answer 135

Computerized axial tomography CT or CAT scan
From the measurements, a computer constructs images of the brain. Helps detect tumours and other structural abnormalities

Question 136

Method of imaging a living brain by using a magnetic field and a radio frequency field to make atoms with odd atomic weights all rotate in the same direction and then removing those fields and measuring the energy that the atoms release

Answer 136

Magnetic resonance imaging MRI

By measuring that energy, MRI devices form an image of the brain, and shows anatomical details smaller than a millimetre in diameter. One drawback is that the person must lie motionless in a confining, noisy apparatus

Question 137

Researchers today sometimes relate differences in people’s behaviour to differences in their brain anatomy. How does their approach differ from that of for phrenologists?

Answer 137

Phrenologists drew conclusions based on just one or a few people with some oddity of behavior. Today’s researchers compare groups statistically. Also, today’s researchers examine the brain itself, not the skull

Question 138

Why are both brain size and brain-two-body ratio unsatisfactory ways of estimating animal intelligence?

Answer 138

If we consider ourselves to be the most intelligent species, we are confronted with the fact that we have neither the largest rains nor the highest brain-to-body ratios. Brain-to-body ratio depends on selection for thinness as well as selection for brain size. Furthermore, animal intelligence is undefined, so we cannot determine what correlates with it.

Question 139

Why do recent studies show a stronger relationship between brain size and IQ than older studies did?

Answer 139

The use of MRI greatly improves the measurement of brain size, in comparison to measurement based on the skull

Question 140

In which way do men and women differ most – intellectual performance, total gray matter, or total white matter?

Answer 140

Men have more white matter, and therefore larger brains. However, men and women are about equal in gray matter and intellectual performance.