Chapter 1 Origins of Brain and Behavior

Question 1

What are the Origins of Brain and Behavior?

Answer 1

• Neuroscience in the Twenty-First Century
• Perspectives on Brain and Behavior
• Evolution of Brains and Behavior
• Evolution of the Human Brain and Behavior
• Modern Human Brain Size and Intelligence

Question 2

Neuroscience in the Twenty-First Century

-Why Study Brain and Behavior?

Answer 2

• Many behavioral disorders can be explained and possibly cured by understanding the brain
• The brain is the most complex living organ on Earth
• How the brain produces both behavior and human consciousness are major unanswered scientific questions

Question 3

This is the Brain: Cerebral Cortex

Answer 3

-Heavily folded outer layer of brain tissue composed of neurons (cortex = “bark”)
~The groves are called SUICI
~The bumps are called GYRI

Question 4

This is the Brian: Right Hemisphere

Answer 4

-Forebrain
~Prominent in mammals and birds, responsible for most conscious behaviors (where we think)
-Brainstem
~Source of behavior in simpler animals, responsible for most of our unconscious behaviors (Breathing, heartbeat, and other things we do not think about)

Question 5

Four Lobes of the Brain

Answer 5

-Frontal
~"Executive" functions, decision making
-Parietal
~Integrates sensations into body coordinates
-Temporal
~Hearing, language, memory, smell, taste
-Occipital
~Visual processing

Question 6

Gross Anatomy of the Nervous System

Answer 6

-The brain and the spinal cord together make up the central nervous system (CNS)
-All nerve processes and neurons outside the CNS connect to
~Sensory receptors
~Muscles
~Internal organs
-Central Nervous System (CNS)
~The brain and spinal cord
-Peripheral Nervous system (PNS)
~Somatic division
*Conveys sensory information to the CNS and motor information from the CNS to the muscles
~Autonomic division
*Enables the CNS to govern the workings of the internal organs (heartbeat, respiration, etc.)

Question 7

Over all works

Answer 7

-Nervous System
~Central Nervous System (CNS)
*Brain
*Spinal Cord
~Peripheral Nervous System (PNS)
*Somatic Nervous System
*Autonomic Nervous System

Question 8

What is Behavior?

Answer 8

-Irenaus Eibl-Eibesfeldt
~”Behavior consists of patterns in time”
~Examples
*Movement, vocalization, thinking
-Animals produce behavior that
~are inherited ways of responding
~that are learned
-Most behaviors probably consist of a mix of inherited and learned actions
-Relatively Fixed (Innate) Behavior
~Directly of heredity
*Eating, for crossbill birds, is a fixed behavioral pattern that is inherited and does not require much modification through learning
-Relatively Flexible behaviors
~Dependent of learning
*Roof rats can eat pinecones efficiently only if they are taught to do so my experienced parent
-Complexity of behavior varies considerably in different species
~Simple Nervous Systems -> Narrow Range of Behavior
*Nervous System (sea slug)
~Complex Nervous Systems -> Wider Range of Behavior
*Nervous Systems (humans)

Question 9

Perspectives on Brain and behavior

-Aristotle and Mentalism

Answer 9

-Mentalism
~An explanation of behavior as a function of the nonmaterial mind
-Ancient Greece: Aristotle
~Believed the brain cooled the blood; no role in producing behavior
~Psyche
*Synonym for mind; an entity once proposed to be the source of human behavior
-The mind is a single entity having an autonomous existence
-The mind is completely and wholly separate from the body
-A manifestation of the soul that will survive the body’s death and return to the creator of your choice (Theological origins)

Question 10

Descartes and Dualism

Answer 10

-Dualism
~both a nonmaterial mind and the material body contribute to behavior
~Mind-Body Problem
*Quandary of explaining a nonmaterial mind in command of a material body
-Rene Descartes
~Mind directs rational behavior
~Body and brain direct all other behavior via mechanical and physical principles
~Example
*Sensation, Movement, and Digestion
~Mind is located in the PINEAL GLAND of the brain, which sits beside ventricles filled with fluid
-Pineal Gland
~Sits in the back of the brain above the brain stem
~The mind regulates the behavior by directing the flow of ventricle fluid to the appropriate muscles
*This is a long time ago before they understood electricity, they did know about fluid dynamics
*The brain is filled with fluid as well as the spinal cord
-Problems with Descartes
~Pineal gland is involved in biological rhythms, but not in intelligence or behavior control
~Fluid is not pumped from the ventricles to control movement
~nonmaterial influences on the body would violate the law of conservation of matter and energy

Question 11

Darwin and Materialism

Answer 11

-Materialism
~Behavior can be explained as a function of the nervous system without explanator recourse to the mind
~Related to evolutionary theories of Alfred Wallace and Charles Darwin
*Both were struck at the many similarities among species
-Darwin’s Concept of Natural Selection
~Explanation for how new species evolve and existing species change over time
-Different success in the reproduction’s of different characteristics (phenotypes) result from the interaction of organisms with their environment
-Because all animal species are related, so too must be their brains
-Because all species of animals are related, so do must be their behaviors
-Can study and understand human behavior and brain function by comparing the genes, brain, and behaviors of different animals

Question 12

How are Traits Selected Naturally?

Answer 12

-Appearance of New Trait
~Via mutation
-Trait Increases Reproductive Success
-Increases Change of Survival
-Trait Passed on to Offspring

Question 13

Epigenetics

Answer 13

• Study of differences in gene expression related to environment and experience
• Epigenetic factors do not change your genes express the traits you’ve inherited from your parents
• Epigenetic changes can persist throughout a lifetime, and the cumulative effects can make dramatic differences in how your genes work

Question 14

Evolution of Brains and Behavior

-Common Ancestor

Answer 14

-A forbearer which two or more lineages or family groups arise
-Example
~Humans and apes are thought to share a common ancestor
-Can trace out lineage by comparing the genes, brains, and behaviors of different animals

Question 15

Evolution of Brain and of Behavior

-Origin of Brain Calles and Brains

Answer 15

-Despite the age of the Earth (4.5 billion years), brain cells and brains are quite recent adaptations
~First form of life: 3.5 billion years old
~First brain cell: 70 million years ago
~First human-like brain: 6 million years ago
~Modern human brain: 200,000 years ago

Question 16

Taxonomy of Modern Humans

Answer 16

-The evolution of brain cells and the brain
~Only Animalia, contains species with muscles and nervous systems
~Muscles and nervous systems evolved together to underlie the forms of movement (behavior) that distinguish members of the animal kingdom
*Study where humans fit in taxonomy

Question 17

Evolution of Brain and Behavior

-Evolution of Animals Having Nervous Systems

Answer 17

-Five different Kingdoms
~Monera
*Bacterial
~Protist
*Single Cells
~Plantae
*Plants
~Fungi
*Fungi
~Animalia
*Animals
-Animals are closer related to fungi than any other kingdom
-Only Animals have nervous systems
~Other kingdoms can react to their environment, but do NOT have a brain or nervous system

Question 18

Evolution of Animals Having Nervous Systems

Answer 18

-Among the various animal phyla, the nervous system has evolved considerably
-Nerve Net
~Simple nervous system with sensory and motor neurons
-Segmented nerve trunk
~Bilaterally symmetrical (the same on both sides of the body)
~Segmented (divided into a number of parts)
-Ganglia
~Structure that resemble and function somewhat like a brain
-Brain
~The chordate phylum display the greatest degree of encephalization: they have a true brain
~Of all the chordates, humans have the largest brain relative to body size

Question 19

Chordate Nervous System

Answer 19

-Nervous systems vary widely among chordates, but all are/have
~Bilaterally symmetrical and segmented
~Brain and spinal cord incased in cartilage/bone
~”Crossed” organization: Each hemisphere receives information from and controls the opposite side of the body
-Emergence of complex behavior^ in chordates is l related to the evolution of the cerebrum and cerebellum
^ New forms of locomotion on land, complex movements of the mouth and hands for eating, improved learning ability, and highly organized social behavior

Question 20

Humans: Members of the Primate Order

Answer 20

-Features common to primates
~Excellent color vision
~Eyes in front of face enhance depth perception
~Females: Usually only one infant per pregnancy; infants require more care
~Large brains for skilled movements and social behavior
-Humans and chimpanzees share a common ancestor 5-10 million years ago
-Hominids
~Evolved 5 million years ago
-Primates that walk upright; includes all forms of humans, living and extinct

Question 21

Australopithecus: Our Distant Ancestor

Answer 21

-Early hominids were among the first primates to show distinctly human characteristics, including walking upright and using tools
~Its brain was the size of that of a modern ape, about one-third the size of the modern human brain

Question 22

First Humans

Answer 22

-Homo habilis (“handy human”)
~2 million years ago; Africa
~Made simple stone tools
-Homo erectus (“upright human”)
~1.6 million years ago; in Europe and Asia
~More sophisticated tools than homo habilis
-Homo sapiens
~Appeared within the last 200,000 years
~Until 30,000 years ago in Europe and 18,000 years ago in Asia, coexisted with other hominid species
~Example
*Neanderthals in Europe, who had comparable or even larger brains than Homo Sapiens
~Exact reason why we replaced Neanderthals is unknown

Question 23

Hominid Brain Size

Answer 23

-The brain of Australopithecus was about the same size as that of living nonhuman apes, but succeeding members of the human lineage display a steady increase in brain size

Question 24

Relating Brain Size and Behavior

Answer 24

-Jerison (1973)
~Principle of Proper Mass:
*Species exhibiting are complex behaviors will possess relatively larger brains
~Jerison developed an index of brain size to allow comparisons among different species
*Used body size to predict brain size
-Encephalization Quotient (EQ)
~Measure of brain size obtained from the ratio of actual brain size to the expected brain size for an animal of a particular body size
*Homo sapiens have the largest EQ

Question 25

Enlarging Hominid Brain

Answer 25

-Relative size of the hominid brain has increased nearly threefold ~Australopithecus afarensis (smallest brain size) ~Homo erectus (larger brain size) ~Modern Homo sapiens (largest brain size)

Question 26

Climate and the Enlarging Hominid Brain

Answer 26

-Evidence suggests each new hominid species appeared after new environments appeared due to climate changes -Example ~Spreading grasslands and fewer trees increased the adaptiveness of an upright posture and tool-building skills

Question 27

Why the Hominid Brain Enlarged

Answer 27

-The Primate Lifestyle ~The foraging behavior of primates is more complex than that of other animals *Finding fruit is more difficult than eating grass or other vegetation on the ground **Need good sensory, spatial, and memory skills *Fruit eaters have larger brain -Changes in Hominid Physiology ~Radiator Hypothesis (Falk, 1990) *The more active the brain is, the more heat it generates *Homo species' skills had more widely disappeared blood flow, which allowed for increased brain size **Increased Blood Circulation -> Improved Brain Cooling -> Enabled Size of Hominid Brains to Increase *The brain uses about 70% of the bodies blood glucose supply **Over 2/3 of the bodies sugar gets consumed by the brain and the other 1/3 is used by the rest of the body * The brain uses about 25% of the bodies O2 -Changes in Hominid Physiology ~Stedman and Colleagues (2004) * Genetic Mutation -> Smaller Facial Muscles and Bones -> Change in Diet -> Increase Brain Size -Neoteny ~Rate of maturation is slowed *Allows more brain cells to be produced ~Adults retain some infant characteristics ~Newly evolved species resemble the young of their common ancestors *Adult human heads look more like the heads of juvenile chimpanzees than adult chimpanzees

Question 28

Modern Human Brain Size and Intelligence

Answer 28

-Evolutionary Approach ~Make brain-behavior comparisons between different species -CAUTION ~Difficult to make brain-behavior comparisons between members within the same species ~Example *Brain size and intelligence -Are people with larger brains more intelligent? ~Problems with answering this question: *Control for skull thickness *Volume versus weight *Control for body weight **Can fluctuate within an individual over time *Effect of age, physical health, brain damage? -Problem of Causality ~Large Brain Size -> Greater Intelligence ~Greater Intelligence -> Large Brain Size ~Other Variables -> Large Brain Size ~Other Variables -> Greater Intelligence`

Question 29

Fallacies of Human Brain-Size Comparisons

Answer 29

- How does one measure intelligence? ~People vary enormously in their individual abilities, depending on the task *Person A **Excellent math abilities **Poor spatial abilities *Person B **Poor math abilities **Excellent spatial abilities *Which person is more intelligent? -Brain size and intelligence do not seem to be particularly related ~Research has shown that many smart people (Einstein) have average size brains ~Women's brain weigh about 10% less than men, but the two sexes do not differ in measures of average intelligence

Question 30

Studying Brain and Behavior in Modern Humans

Answer 30

-Culture ~Learning behaviors that are passed on from one generation to the next through teaching and learning *Enabled by out large brains -The brain is highly flexible ~We preform many tasks today that our brains were not originally selected for early during evolution ~Example *Programming computers

Question 31

Traumatic Brain Injur

Answer 31

-Wound to the brain that results from a blow to the head

Question 32

Concussion

Answer 32

-Damage to the brain caused by a blow to the head

Question 33

Neurons

Answer 33

- 87 billion brain cells about half | - Specialized nerve cell engage in information processing

Question 34

Glial Cells

Answer 34

- 86 billion brain cells about half | - Brain cells that support the function of neurons

Question 35

Central Nervous System (CNS)

Answer 35

-The brain and spinal cord, which together mediate behavior

Question 36

Peripheral Nervous System (PNS)

Answer 36

-All the neurons in the body outside the brain and spinal cord; provides sensory and motor connections to and from the Central Nervous System ~Skin ~Muscles ~Organs

Question 37

Cerebrum (forebrain)

Answer 37

-Major structure of the forebrain that consists of two mirror-image hemispheres (left and right) and is responsible for most conscious behavior

Question 38

Hemispheres

Answer 38

- Literally, half a sphere, referring to one side of the cerebrum

Question 39

Brainstem

Answer 39

-Central structure of the brain; responsible for most unconscious behaviors

Question 40

Cerebellum

Answer 40

-Major brainstem structure specialized for learning and coordinating movements assists the cerebrum in generating many behaviors

Question 41

Embodied Behavior

Answer 41

-Theory that the movements we make and the movements we perceive in others are central to communication with others

Question 42

Lock-in Syndrome

Answer 42

-Condition in which a patient is aware and awake but cannot move or communicate verbally because if complete paralysis of nearly all voluntary muscles except the eyes

Question 43

Minimally Conscious State (MCS)

Answer 43

-Condition in which a person can display some rudimentary behaviors, such as smiling or uttering a few words, but is otherwise not conscious

Question 44

Clinical Trials

Answer 44

-Consensual experiments directed towards developing a treatment

Question 45

Deep Brain Stimulation (DBS)

Answer 45

-Neurosurgery in which electrodes implanted in the brain stimulate a targeted area with a low-voltage electrical current to facilitate behavior

Question 46

Persistent Vegetative State (PVS)

Answer 46

-Condition in which a person is alive but unaware, unable to communicate or to function independently at even the most basic level

Question 47

Psyche

Answer 47

-Synonym for mind, an entity once proposed to be the source of human behavior

Question 48

Mentalism

Answer 48

-Explanation of behavior as a function of the nonmaterial mind

Question 49

Dualism

Answer 49

-Philosophical position that both nonmaterial mind and a material body contribute to behavior

Question 50

Mind-body Problem

Answer 50

-Difficulty of explaining how a nonmaterial mind and a material mind interact

Question 51

Materialism

Answer 51

-Philosophical position that behavior can be explained as a function of the nervous system without recourse to the mind

Question 52

Natural Selection

Answer 52

-Darwin's theory explaining how new species change over time. Differential success in the reproduction of different characteristics (phenotypes) results from the interaction of organisms with their environment

Question 53

Species

Answer 53

-Group of organisms that can interbreed

Question 54

Phenotypes

Answer 54

-Ste of individual characteristics that can be seen or measured

Question 55

Genotypes

Answer 55

-Particular genetic makeup of an individual

Question 56

Epigenetics

Answer 56

-Differences in gene expression related to environment and experience

Question 57

Nerve Net

Answer 57

-Simple nervous system that has no center but consists of neurons that receive sensory information and connect directly to other neurons that move muscle

Question 58

Bilateral symmetry

Answer 58

-Body plan in which organs or part present on both sides of the body are mirror images in appearance -Example ~The hands are bilaterally symmetrical, whereas the heart is not

Question 59

Segmentation

Answer 59

-Division into a number of parts that are similar; refers to the idea that many animals, including vertebrates, are composed of similarly organized body segments

Question 60

Chordate

Answer 60

-Animal that has both a brain and a spinal cord

Question 61

Cladogram

Answer 61

-Phylogenetic tree that branches repeatedly, suggesting a taxonomy of organisms based on the time sequence in which evolutionary branches arise

Question 62

Hominid

Answer 62

-General term referring to primates that walk upright, including all forms of humans, living and extinct

Question 63

Encephalization Quotient (EQ)

Answer 63

-Jerison's quantitative measure of brain size obtained from the ratio of actual brain size to expected brain size, according to the principle of proper mass, for an animal of a particular body size

Question 64

Topographic

Answer 64

-Representing the different functional areas of the CNS

Question 65

Connectome

Answer 65

-All the pathways connecting regions of the CNS

Question 66

Neoteny

Answer 66

-Process in which juvenile stages of predecessors become adult features of descendants; idea derived from the observation that more recently evolved species resemble the young of their common ancestors

Question 67

Plasticity

Answer 67

-Body's potential for physical or chemical change; enhances its adaptability to environmental change and its ability to compensate for injury, (In the brain and nervous system, this potential is called NEUROPLASTICITY)

Question 68

Species-Typical Behavior

Answer 68

-Behavior that is characteristic of all members of a species, such as walking in salamanders

Question 69

Culture

Answer 69

-Learned behaviors that are passed on from one generation to the next through teaching and imitation

Question 70

Meme

Answer 70

-An idea, a behavior, or style that spreads from person to person within a culture