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Learning Unit 4 BIOLOGICAL FOUNDATIONS OF BEHAVIOR

1

Module 2.1 Neurons: The Body’s Wiring

2

Neuron

Neuron - Nerve cells – basic building block of the nervous system

Specialized cells that transmit info. throughout the body in the form of electrical impulses

3

Neuron Neurogenesis

◦ The process of developing new neurons

Repairing the brain ◦ Human brains have limited capacity to replace, rewire, or repair

damaged neurons after stroke, head wound, blow to the head

◦ People may regain some, but rarely all, of function after such an incident

4

PARTS OF THE NEURON Cell body (AKA Soma)

Large egg-shaped structure that provides fuel, manufactures chemicals, and maintains the entire neuron in working order

5

Parts of the Neuron Dendrite

◦ Branch/root-like extensions that arise from the cell body

◦ Has receptor sites that enable them to receive neurotransmitters released from other neurons.

6

PARTS OF THE NEURON (CONT’D) Axon:

◦ A single thread-like structure that extends/carries signals away from the cell body to neighboring neurons, organs, or muscles

7

Parts of the Neuron Myelin sheath

◦ Looks like separate tube-like segments composed of fatty material that wraps around and insulates an axon

Formed by glial cells – small cells that act like glue to hold neurons together.

“Glial” – Greek “glue”

8

PARTS OF THE NEURON (CONT’D) Terminal Buttons

◦ Located at extreme ends of the axon’s branches

◦ Miniature container that stores & releases chemicals called neurotransmitters (used to communicate with neighboring cells)

9

10

KINDS OF NEURONS

Sensory Neurons– transmit information about the outside world TO the spinal cord & brain.

Motor Neurons– transmit messages FROM the brain and spinal cord to the muscles that control the movements of your body.

11

KINDS OF NEURONS

Interneurons AKA Associative Neurons – connect neurons to neurons.

◦ Most common neuron in the nervous system.

12

That took a lot of nerve!

13

Synapse Infinitely small fluid-filled gap - Less than a millionth of an inch wide

Exists between a terminal button and its adjacent body organ (heart), muscles (head), or cell body/dendrite

14

How Neurons Communicate

15

How Neurons Communicate The resting potential is the electrical potential across the cell membrane of a neuron in its resting state.

◦ The resting potential of a neuron is about -70 millivolts (mV).

When the cell is stimulated, sodium gates at the base of the axon open. Positively charged sodium ions rush into the cell, which causes the area inside the cell membrane at the point of excitation to become less negatively charged.

◦ This process is called depolarization.

An action potential is an abrupt change from a negative to a positive charge of a nerve cell, also called a neural impulse.

16

Neurotransmitters • Neurotransmitters are chemical messengers

• Each type of neurotransmitter fits into only one kind of receptor site.

• Reuptake is the process by which neurotransmitters are reabsorbed by

the transmitting neurons.

• Other neurotransmitters may be broken down by enzymes.

• Neuromodulators are chemicals that either increase or decrease the

sensitivity of the receiving neuron to neurotransmitters.

17

Neurotransmitters

18

Antagonists

Drugs or chemicals that block the actions of neurotransmitters by occupying their receptor sites.

Prevent transmission of the messages the neurotransmitter carries.

19

Agonists

Drugs or chemicals that enhance the activity of neurotransmitters.

Increase the availability or effectiveness of neurotransmitters by binding to their receptor sites and mimicking their actions.

20

Neurotransmitters

Endorphins – “morphine within” natural, opiate- like neurotransmitters linked to pain control and pleasure.

◦ Runners high

◦ Indifference to pain that sometimes follows severe injuries.

21

Mirror Neurons Neurons that fire both when an action is performed and when the same action is merely observed.

22

23

Module 2.2 THE NERVOUS SYSTEM: YOUR BODY’S INFORMATION SUPERHIGHWAY

24

The Central Nervous System: Your Body’s Master Control Unit (1 of 2)

The nervous system consists of two components:

• the central nervous system, composed of the brain and spinal cord, and

• the peripheral nervous system.

25

The Central Nervous System: Your Body’s Master Control Unit (2 of 2)

26

The Peripheral Nervous System: Your Body’s Link to the Outside World (1 of 2)

The peripheral nervous system (PNS) is the part of the nervous system that connects the spinal cord and brain with the sensory organs, muscles, and glands.

The PNS is divided into two parts: ◦ Somatic nervous system

◦ Autonomic nervous system (ANS)

27

The Peripheral Nervous System: Your Body’s Link to the Outside World (2 of 2)

The ANS is composed of two divisions, or branches, that have largely opposite effects:

◦ The sympathetic nervous system

◦ The parasympathetic nervous system

28

Organization of the Nervous System

29

Parts of the Brain

30

The Brainstem

➢Responsible for automatic survival functions

➢Functions occur without any conscious effort – our brain processes most info. outside of our awareness

➢Brainstem begins where the spinal cord enters the skull and swells slightly forming the medulla.

31

Parts of the Brain: Hindbrain The hindbrain is the lowest and, in evolutionary terms, oldest part of the brain.

The hindbrain includes: ◦ Medulla

◦ Pons

◦ Cerebellum

32

Hindbrain

• Medulla • Located on top of the spinal cord

• Includes a group of cells that control vital reflexes, such as respiration, heart rate, and blood pressure

33

Hindbrain

• Pons

• Functions as a bridge to interconnect messages between the spinal cord and brain.

• Helps regulate states of sleep & wakefulness

34

Hindbrain

• Cerebellum – “Little Brain”

• Balance & Coordination

• Involved in coordinating motor movements but not in initiating voluntary movements

• Processes sensory input & coordinates movement output & balance

35

Midbrain

• Lies above the hindbrain, connects nerve pathways that connect the hindbrain with the forebrain.

• Parts of the midbrain make up the brainstem

• Reticular formation – neural network that rises from the hindbrain & passes through the midbrain to the thalamus in the forebrain.

• Regulates attention, alertness, & arousal

36

Forebrain

• The forebrain is the largest and uppermost part of the brain.

• The forebrain includes:

• Thalamus

• Basal ganglia

• Hypothalamus

• Limbic system

37

Forebrain

• The largest part of the brain.

• Major structures include the thalamus, hypothalamus, limbic system, & cerebral cortex.

38

Forebrain: Limbic System

• Thalamus – (switchboard/relay station) involved in receiving sensory information from all of the senses except for smell.

39

Forebrain: Limbic System • Hypothalamus – regulates many

motivational behaviors, eating, drinking, sleep cycles, & sexual arousal, emotional responses – fight & flight (bodily response to stress), emotional states, & aggressive behavior & the secretion of hormones.

40

Forebrain: Limbic System

Amygdala – 2 almond-shaped neural clusters located at the tip of the temporal lobe, that influence aggression, fear & processing of emotional memories.

• Plays a role in evaluating emotional significance of stimuli & facial expressions – particularly fear, distress, or threat.

41

Forebrain: Limbic System

• Hippocampus – a curved structure shaped like a sea horse, located in the temporal lobe that is involved in saving memories & putting them into permanent storage in various parts of the brain.

42

Forebrain •Cerebral Cortex – (Latin – “Cover”) – Wrinkled surface of brain

•Intricate covering of interconnected neural cells that forms a thin surface layer over your cerebrum, the largest part of the forebrain which consists of 2 large masses, the right & left cerebral hemispheres. • Brain’s outer “bark” layer.

•Corpus Callosum – Latin “Thick Body” connects cerebral hemispheres & share information.

43

Forebrain • Located in front part of brain

•Called the “Executive Center”

• Many functions

• voluntary motor movements, interpreting and performing emotional behaviors, behaving normally in social situations, maintaining a healthy personality, paying attention to things in the environment etc.

•Frontal lobes shrink as we age.

44

Damage to the Frontal Lobe Phineas Gage

45

Forebrain Frontal Lobe •Motor Cortex - Narrow strip of cortex that’s located on the back edge of the frontal lobe and extends down its side

•Involved in the initiation of all voluntary movements • Right side controls left

• Left side controls right

•Organization and function of motor cortex

46

Motor Cortex Body parts that utilize precision control or fine motor skills (fingers, tongue) occupy the greatest amount of cortical space.

47

Forebrain Parietal Lobes oParietal Lobes –Processes sensory information from body parts, touching, locating positions of limbs, feeling temperature & pain

48

Forebrain Parietal Lobes Somatosensory cortex – narrow strip of cortex located on the front edge of the parietal lobe & down it’s side.

◦ Processes sensory information about touch, location of limbs, pain & temperature.

49

Cerebral Cortex - Sensory Cortex Stimulate 1 point on the top of this band of tissue and the person may report being touched on the shoulder, stimulate some point on the side and the person may feel something on the face.

The more sensitive a body region, the larger the area of the sensory cortex devoted to it. Lips project to a larger brain area than your toes

50

51

Forebrain Occipital Lobes ❖Occipital Lobe – Located at the back

of the brain. Involved in processing visual information, which includes seeing colors and perceiving and recognizing objects, animals, & people.

52

Forebrain Temporal Lobes •Temporal Lobe – Receive & process sensory information from the ears, producing the experience of hearing. • Involved in hearing, speaking

coherently and understanding verbal & written material.

53

Cortex •Association Areas – areas of the cerebral cortex that piece together sensory information to form meaningful perceptions of the world and perform higher mental functions.

54

OVERALL VIEW OF THE CORTEX

55

56

Module 2.4 METHODS OF STUDYING THE BRAIN

57

Brain Plasticity ➢Plasticity – the ability of the brain to adapt itself after trauma or surgical alteration.

➢Plasticity is strongest during childhood.

58

Electroencephalograph (EEG)

•Electrodes attached to scalp

•Records electrical activity in the brain.

•Measures electrical currents or brain waves.

•Often used to study sleep brain wave patterns & electrical activity in brain of people with physical or psychological disorders.

59

CT (Computed Tomography) Scan AKA CAT Scan (Computed Axial Tomography)

•Imaging technique in which a computer measures the reflection of a narrow X-ray beam from various angles as it passes through the brain or other bodily structures

60

Positron Emission Tomography Scan (PET Scan)

A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

Observe which parts of the brain light up when given different tasks. ◦ Red & yellow indicate high activity while blue &

green indicate lower levels of activity.

61 Images from radiologyinfo.org

Magnetic Resonance Imaging (MRI) Technique uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue

Allows us to see the anatomy of the brain.

62

Functional MRI (fMRI)

Can reveal brain’s structure & functioning

Reveals blood flow and brain activity by comparing successive MRI scans

Shows brain function – measures changes in activity of specific neurons that are functioning during cognitive tasks, such as thinking, listening, or reading.

63

Learning Unit 4 BIOLOGICAL FOUNDATIONS OF BEHAVIOR

1

Module 2.1 Neurons: The Body’s Wiring

2

Neuron

Neuron - Nerve cells – basic building block of the nervous system

Specialized cells that transmit info. throughout the body in the form of electrical impulses

3

Neuron Neurogenesis

◦ The process of developing new neurons

Repairing the brain ◦ Human brains have limited capacity to replace, rewire, or repair

damaged neurons after stroke, head wound, blow to the head

◦ People may regain some, but rarely all, of function after such an incident

4

PARTS OF THE NEURON Cell body (AKA Soma)

Large egg-shaped structure that provides fuel, manufactures chemicals, and maintains the entire neuron in working order

5

Parts of the Neuron Dendrite

◦ Branch/root-like extensions that arise from the cell body

◦ Has receptor sites that enable them to receive neurotransmitters released from other neurons.

6

PARTS OF THE NEURON (CONT’D) Axon:

◦ A single thread-like structure that extends/carries signals away from the cell body to neighboring neurons, organs, or muscles

7

Parts of the Neuron Myelin sheath

◦ Looks like separate tube-like segments composed of fatty material that wraps around and insulates an axon

Formed by glial cells – small cells that act like glue to hold neurons together.

“Glial” – Greek “glue”

8

PARTS OF THE NEURON (CONT’D) Terminal Buttons

◦ Located at extreme ends of the axon’s branches

◦ Miniature container that stores & releases chemicals called neurotransmitters (used to communicate with neighboring cells)

9

10

KINDS OF NEURONS

Sensory Neurons– transmit information about the outside world TO the spinal cord & brain.

Motor Neurons– transmit messages FROM the brain and spinal cord to the muscles that control the movements of your body.

11

KINDS OF NEURONS

Interneurons AKA Associative Neurons – connect neurons to neurons.

◦ Most common neuron in the nervous system.

12

That took a lot of nerve!

13

Synapse Infinitely small fluid-filled gap - Less than a millionth of an inch wide

Exists between a terminal button and its adjacent body organ (heart), muscles (head), or cell body/dendrite

14

How Neurons Communicate

15

How Neurons Communicate The resting potential is the electrical potential across the cell membrane of a neuron in its resting state.

◦ The resting potential of a neuron is about -70 millivolts (mV).

When the cell is stimulated, sodium gates at the base of the axon open. Positively charged sodium ions rush into the cell, which causes the area inside the cell membrane at the point of excitation to become less negatively charged.

◦ This process is called depolarization.

An action potential is an abrupt change from a negative to a positive charge of a nerve cell, also called a neural impulse.

16

Neurotransmitters • Neurotransmitters are chemical messengers

• Each type of neurotransmitter fits into only one kind of receptor site.

• Reuptake is the process by which neurotransmitters are reabsorbed by

the transmitting neurons.

• Other neurotransmitters may be broken down by enzymes.

• Neuromodulators are chemicals that either increase or decrease the

sensitivity of the receiving neuron to neurotransmitters.

17

Neurotransmitters

18

Antagonists

Drugs or chemicals that block the actions of neurotransmitters by occupying their receptor sites.

Prevent transmission of the messages the neurotransmitter carries.

19

Agonists

Drugs or chemicals that enhance the activity of neurotransmitters.

Increase the availability or effectiveness of neurotransmitters by binding to their receptor sites and mimicking their actions.

20

Neurotransmitters

Endorphins – “morphine within” natural, opiate- like neurotransmitters linked to pain control and pleasure.

◦ Runners high

◦ Indifference to pain that sometimes follows severe injuries.

21

Mirror Neurons Neurons that fire both when an action is performed and when the same action is merely observed.

22

23

Module 2.2 THE NERVOUS SYSTEM: YOUR BODY’S INFORMATION SUPERHIGHWAY

24

The Central Nervous System: Your Body’s Master Control Unit (1 of 2)

The nervous system consists of two components:

• the central nervous system, composed of the brain and spinal cord, and

• the peripheral nervous system.

25

The Central Nervous System: Your Body’s Master Control Unit (2 of 2)

26

The Peripheral Nervous System: Your Body’s Link to the Outside World (1 of 2)

The peripheral nervous system (PNS) is the part of the nervous system that connects the spinal cord and brain with the sensory organs, muscles, and glands.

The PNS is divided into two parts: ◦ Somatic nervous system

◦ Autonomic nervous system (ANS)

27

The Peripheral Nervous System: Your Body’s Link to the Outside World (2 of 2)

The ANS is composed of two divisions, or branches, that have largely opposite effects:

◦ The sympathetic nervous system

◦ The parasympathetic nervous system

28

Organization of the Nervous System

29

Parts of the Brain

30

The Brainstem

➢Responsible for automatic survival functions

➢Functions occur without any conscious effort – our brain processes most info. outside of our awareness

➢Brainstem begins where the spinal cord enters the skull and swells slightly forming the medulla.

31

Parts of the Brain: Hindbrain The hindbrain is the lowest and, in evolutionary terms, oldest part of the brain.

The hindbrain includes: ◦ Medulla

◦ Pons

◦ Cerebellum

32

Hindbrain

• Medulla • Located on top of the spinal cord

• Includes a group of cells that control vital reflexes, such as respiration, heart rate, and blood pressure

33

Hindbrain

• Pons

• Functions as a bridge to interconnect messages between the spinal cord and brain.

• Helps regulate states of sleep & wakefulness

34

Hindbrain

• Cerebellum – “Little Brain”

• Balance & Coordination

• Involved in coordinating motor movements but not in initiating voluntary movements

• Processes sensory input & coordinates movement output & balance

35

Midbrain

• Lies above the hindbrain, connects nerve pathways that connect the hindbrain with the forebrain.

• Parts of the midbrain make up the brainstem

• Reticular formation – neural network that rises from the hindbrain & passes through the midbrain to the thalamus in the forebrain.

• Regulates attention, alertness, & arousal

36

Forebrain

• The forebrain is the largest and uppermost part of the brain.

• The forebrain includes:

• Thalamus

• Basal ganglia

• Hypothalamus

• Limbic system

37

Forebrain

• The largest part of the brain.

• Major structures include the thalamus, hypothalamus, limbic system, & cerebral cortex.

38

Forebrain: Limbic System

• Thalamus – (switchboard/relay station) involved in receiving sensory information from all of the senses except for smell.

39

Forebrain: Limbic System • Hypothalamus – regulates many

motivational behaviors, eating, drinking, sleep cycles, & sexual arousal, emotional responses – fight & flight (bodily response to stress), emotional states, & aggressive behavior & the secretion of hormones.

40

Forebrain: Limbic System

Amygdala – 2 almond-shaped neural clusters located at the tip of the temporal lobe, that influence aggression, fear & processing of emotional memories.

• Plays a role in evaluating emotional significance of stimuli & facial expressions – particularly fear, distress, or threat.

41

Forebrain: Limbic System

• Hippocampus – a curved structure shaped like a sea horse, located in the temporal lobe that is involved in saving memories & putting them into permanent storage in various parts of the brain.

42

Forebrain •Cerebral Cortex – (Latin – “Cover”) – Wrinkled surface of brain

•Intricate covering of interconnected neural cells that forms a thin surface layer over your cerebrum, the largest part of the forebrain which consists of 2 large masses, the right & left cerebral hemispheres. • Brain’s outer “bark” layer.

•Corpus Callosum – Latin “Thick Body” connects cerebral hemispheres & share information.

43

Forebrain • Located in front part of brain

•Called the “Executive Center”

• Many functions

• voluntary motor movements, interpreting and performing emotional behaviors, behaving normally in social situations, maintaining a healthy personality, paying attention to things in the environment etc.

•Frontal lobes shrink as we age.

44

Damage to the Frontal Lobe Phineas Gage

45

Forebrain Frontal Lobe •Motor Cortex - Narrow strip of cortex that’s located on the back edge of the frontal lobe and extends down its side

•Involved in the initiation of all voluntary movements • Right side controls left

• Left side controls right

•Organization and function of motor cortex

46

Motor Cortex Body parts that utilize precision control or fine motor skills (fingers, tongue) occupy the greatest amount of cortical space.

47

Forebrain Parietal Lobes oParietal Lobes –Processes sensory information from body parts, touching, locating positions of limbs, feeling temperature & pain

48

Forebrain Parietal Lobes Somatosensory cortex – narrow strip of cortex located on the front edge of the parietal lobe & down it’s side.

◦ Processes sensory information about touch, location of limbs, pain & temperature.

49

Cerebral Cortex - Sensory Cortex Stimulate 1 point on the top of this band of tissue and the person may report being touched on the shoulder, stimulate some point on the side and the person may feel something on the face.

The more sensitive a body region, the larger the area of the sensory cortex devoted to it. Lips project to a larger brain area than your toes

50

51

Forebrain Occipital Lobes ❖Occipital Lobe – Located at the back

of the brain. Involved in processing visual information, which includes seeing colors and perceiving and recognizing objects, animals, & people.

52

Forebrain Temporal Lobes •Temporal Lobe – Receive & process sensory information from the ears, producing the experience of hearing. • Involved in hearing, speaking

coherently and understanding verbal & written material.

53

Cortex •Association Areas – areas of the cerebral cortex that piece together sensory information to form meaningful perceptions of the world and perform higher mental functions.

54

OVERALL VIEW OF THE CORTEX

55

56

Module 2.4 METHODS OF STUDYING THE BRAIN

57

Brain Plasticity ➢Plasticity – the ability of the brain to adapt itself after trauma or surgical alteration.

➢Plasticity is strongest during childhood.

58

Electroencephalograph (EEG)

•Electrodes attached to scalp

•Records electrical activity in the brain.

•Measures electrical currents or brain waves.

•Often used to study sleep brain wave patterns & electrical activity in brain of people with physical or psychological disorders.

59

CT (Computed Tomography) Scan AKA CAT Scan (Computed Axial Tomography)

•Imaging technique in which a computer measures the reflection of a narrow X-ray beam from various angles as it passes through the brain or other bodily structures

60

Positron Emission Tomography Scan (PET Scan)

A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

Observe which parts of the brain light up when given different tasks. ◦ Red & yellow indicate high activity while blue &

green indicate lower levels of activity.

61 Images from radiologyinfo.org

Magnetic Resonance Imaging (MRI) Technique uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue

Allows us to see the anatomy of the brain.

62

Functional MRI (fMRI)

Can reveal brain’s structure & functioning

Reveals blood flow and brain activity by comparing successive MRI scans

Shows brain function – measures changes in activity of specific neurons that are functioning during cognitive tasks, such as thinking, listening, or reading.

63