Biological Psychology. Phrenology (Franz Gall) branch of psychology concerned with the links between biology and behavior

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1 Neural Communication Biological Psychology branch of psychology concerned with the links between biology and behavior some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists Phrenology (Franz Gall) Study of the bumps on your head Bumps reveal a person s abilities and traits

2 Phrenology

3 Neural Communication Neuron a nerve cell the basic building Soma block of the nervous system cell body; serves as neuron s control center

4 Neural Communication Dendrite the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body Axon the extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands Myelin [MY-uh-lin] Sheath a layer of fatty cells segmentally encasing the fibers of many neurons enables vastly greater transmission speed of neutral impulses

5 Neural Communication

6 Neural Communication Action Potential a neural impulse; a brief electrical charge that travels down an axon generated by the movement of positively charged atoms in and out of channels in the axon s membrane Threshold the level of stimulation required to trigger a neural impulse

7 Neural Communication Cell body end of axon Direction of neural impulse: toward axon terminals

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9 Action Potential Within a Neuron

10 How Neurons Communicate Neurons communicate by means of an electrical signal called the Action Potential Action Potentials are based on movements of ions between the outside and inside of the cell When an Action Potential occurs, a molecular message is sent to neighboring neurons

11 Resting Potential At rest, the inside of the cell is at -70 microvolts With inputs to dendrites inside becomes more positive If resting potential rises above threshold, an action potential starts to travel from cell body down the axon Figure shows resting axon being approached by an AP

12 Depolarization Ahead of AP AP opens cell membrane to allow sodium (Na + ) in Inside of cell rapidly becomes more positive than outside This depolarization travels down the axon as leading edge of the AP

13 Repolarization follows After depolarization potassium (K + ) moves out restoring the inside to a negative voltage This is called repolarization The rapid depolarization and repolarization produce a pattern called a spike discharge

14 Finally, Hyperpolarization Repolarization leads to a voltage below the resting potential, called hyperpolarization Now neuron cannot produce a new action potential This is the refractory period

15 Neural Communication Synapse [SIN-aps] junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron tiny gap at this junction is called the synaptic gap or cleft Neurotransmitters chemical messengers that traverse the synaptic gaps between neurons when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

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17 Neurotransmitter Release Action Potential causes vesicle to open Neurotransmitter released into synapse Locks onto receptor molecule in postsynaptic membrane

18 Neural Communication

19 Locks and Keys Neurotransmitter molecules have specific shapes Receptor molecules have binding sites When NT binds to receptor, ions enter

20 Some Drugs Work on Receptors Some drugs are shaped like neurotransmitters Antagonists: fit the receptor but poorly and block the NT e.g., beta blockers Agonists: fit receptor well and act like the NT e.g., nicotine

21 Neural Communication Serotonin Pathways Dopamine Pathways

22 Dopamine Involved in movement, attention and learning Dopamine imbalance also involved in schizophrenia Loss of dopamine-producing neurons is cause of Parkinson s disease

23 Parkinson s Disease Results from loss of dopamine-producing neurons Symptoms include difficulty starting and stopping voluntary movements tremors at rest stooped posture rigidity poor balance

24 Parkinson s Disease Treatments L-dopa transplants of fetal dopamine-producing substantia nigra cells adrenal gland transplants electrical stimulation of the thalamus has been used to stop tremors

25 Serotonin Involved in sleep Involved in depression Prozac works by keeping serotonin in the synapse longer, giving it more time to exert an effect

26 Excitatory and Inhibitory Messages Excitatory message increases the likelihood that the postsynaptic neuron will activate Inhibitory message decreases the likelihood that the postsynaptic neuron will activate.

27 Neural Communication Neurotransmitter molecule Receiving cell membrane Receptor site on receiving neuron Agonist mimics neurotransmitter Antagonist blocks neurotransmitter

28 Acetylcholine First neurotransmitter discovered Ach is found in all motor neurons It stimulates muscles to contract, including the heart and stomach muscles Primary Roles: learning, memory, muscle contractions

29 Disruption of Acetylcholine Functioning Curare blocks ACh receptors paralysis results Nerve gases and Black Widow spider venom; too much ACh leads to severe muscle spasms and possible death

30 Disruptions in ACh Functioning Cigarettes nicotine works on ACh receptors can artificially stimulate skeletal muscles, leading to slight trembling movements

31 Alzheimer s Disease Deterioration of memory, reasoning, and language skills Symptoms may be due to loss of ACh neurons

32 Endorphins Control pain and pleasure Released in response to pain Morphine and codeine work on endorphin receptors; involved in healing effects of acupuncture Runner s high feeling of pleasure after a long run is due to heavy endorphin release

33 Norepinephrine Arousal Fight or flight response Primary Roles: physical arousal, learning, memory Disorders: depression

34 GABA Inhibition of brain activity Huntington s disease involves loss of neurons in striatum that utilize GABA Symptoms: jerky involuntary movements mental deterioration

35 Glutamate Major excitatory neurotransmitter Too much glutamate (and too little GABA) associated with epileptic seizures

36 Neural Communication

37 Summary Neuron structure Action potentials Synapse Neurotransmitters Receptors and ions Agonists and antagonists

38 The Nervous System Nerves neural cables containing many axons part of the peripheral nervous system connect the central nervous system with muscles, glands, and sense organs

39 Aaron Ralston

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41 Neurons and Synapses Types of Neurons Sensory Motor Interneurons

42 Sensory Neurons INPUT From sensory organs to the brain and spinal cord Drawing shows a somatic neuron Also called AFFERENT NEURONS Sensory Neuron Brain Spinal Cord

43 Motor Neurons OUTPUT From the brain and spinal cord, to the muscles and glands Also called EFFERENT NEURONS Sensory Neuron Brain Spinal Cord Motor Neuron

44 Interneurons Interneurons carry information between other neurons only found in the brain and spinal cord Sensory Neuron Motor Neuron Brain Spinal Cord

45 The Nervous System Nervous System the body s speedy, electrochemical communication system consists of all the nerve cells of the peripheral and central nervous systems Peripheral Nervous System (PNS) the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

46 The Nervous System Nervous system Peripheral Central (brain and spinal cord) Autonomic (controls self-regulated action of internal organs and glands) Skeletal (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming)

47 The Nervous System Somatic Nervous System the division of the peripheral nervous system that controls the body s skeletal muscles Autonomic Nervous System the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart)

48 The Nervous System Sympathetic Nervous System division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations Parasympathetic Nervous System division of the autonomic nervous system that calms the body, conserving its energy

49 The Nervous System

50 The Nervous System

51 Brain and Spinal Cord Central Nervous System (CNS) the brain and spinal cord Brain part of the CNS that plays important roles in sensation, movement, and information processing. Spinal Cord plays a role in body reflexes and in communication between the brain and the peripheral nervous system.

52 The Nervous System Reflex a simple, automatic, inborn response to a sensory stimulus Brain Sensory neuron (incoming information) Interneuron Muscle Motor neuron (outgoing information) Spinal cord Skin receptors

53 The Nervous System Inputs Neurons in the brain connect with one another to form networks The brain learns by modifying certain connections in response to feedback Neural Networks interconnected neural cells with experience, networks can learn, as feedback strengthens Outputs or inhibits connections that produce certain results computer simulations of neural networks show analogous learning

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55 The Brain Lesion tissue destruction a brain lesion is a naturally or experimentally caused destruction of brain tissue

56 Electroencephalogram (EEG) an amplified recording of the waves of electrical activity that sweep across the brain s surface these waves are measured by electrodes placed on the scalp

57 The Brain CT (computed tomography) Scan a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; also called CAT scan PET (positron emission tomography) Scan a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

58 PET Scan

59 PET Scan

60 The Brain MRI (magnetic resonance imaging) a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain Stimulation Electrical stimulation of the brain involves sending a weak electric current into a brain structure to stimulate it. (It is not painful because the brain has no pain receptors

61 MRI Scan

62 The Brain Brainstem the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull responsible for automatic survival functions

63 Developing Brain Neural tube beginning of nervous system develops at 2 weeks after conception Neurogenesis development of new neurons

64 Hindbrain Structures Cerebellum Brainstem medulla reticular formation pons

65 Medulla Breathing Heart rate Digestion Other vital reflexes swallowing coughing vomiting sneezing

66 Pons Helps coordinate movements on left and right sides of the body e.g., postural reflexes which help you maintain balance while standing or moving

67 Reticular Formation Network of neurons in the brainstem (and thalamus) Sleep and arousal Attention

68 Coordinated, rapid voluntary movements e.g., playing the piano, kicking, throwing, etc. Lesions to cerebellum jerky, exaggerated movements difficulty walking loss of balance shaking hands Cerebellum

69 The Brain Cerebellum [sehr-uh-bellum] the little brain attached to the rear of the brainstem it helps coordinate voluntary movement and balance

70 Thalamus Limbic System Cortex Forebrain Structures

71 Thalamus Relay station in brain Processes most information to and from higher brain centers

72 The Limbic System

73 The Limbic System Hypothalamus Amygdala Hippocampus

74 The Limbic System Electrode implanted in reward center

75 Amygdala and Emotion Identify emotion from facial expressions Amygdala damage makes this task difficult

76 Hypothalamus Contains nuclei involved in a variety of behaviors sexual behavior hunger, thirst sleep water and salt balance body temperature regulation circadian rhythms role in hormone secretion

77 Hypothalamus and Hormones Hypothalamus releases hormones or releasing factors which in turn cause pituitary gland to release its hormones

78 Hippocampus Hippocampus structure that contributes to the formation of memories. Damage to the hippocampus has been implicated in the memory loss associated with Alzheimer s.

79 The Cerebral Cortex Cerebral Cortex the intricate fabric of interconnected neural cells that covers the cerebral hemispheres the body s ultimate control and information processing center Glial Cells cells in the nervous system that support, nourish, and protect neurons

80 The Cerebral Cortex Frontal Lobes involved in speaking and muscle movements and in making plans and judgments Parietal Lobes include the sensory cortex & processes somatic information Occipital Lobes include the visual areas, which receive visual information from the opposite visual field Temporal Lobes include the auditory areas

81 The Cerebral Cortex Motor Cortex area at the rear of the frontal lobes that controls voluntary movements Sensory Cortex area at the front of the parietal lobes that registers and processes body sensations

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84 The Cerebral Cortex

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86 The Cerebral Cortex Functional MRI scan shows the visual cortex activated as the subject looks at faces

87 Visual and Auditory Cortex

88 Association Areas Association Areas Areas of the cerebral cortex that are not involved in primary motor or sensory functions. They are involved in higher mental functions such as learning, remembering, thinking and speaking. Phineas Gage

89 Association Areas More intelligent animals have increased uncommitted or association areas of the cortex

90 The Cerebral Cortex Aphasia impairment of language, usually caused by left hemisphere damage either to Broca s area (impairing speaking) or to Wernicke s area (impairing understanding) Broca s Area (Disrupts speaking) an area of the left frontal lobe that directs the muscle movements involved in speech Wernicke s Area (Disrupts understanding) an area of the left temporal lobe involved in language comprehension and expression

91 Specialization and Integration

92 Specialization and Integration Brain activity when hearing, seeing, and speaking words

93 Brain Reorganization Plasticity the brain s capacity for modification, as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development

94 Brain Reorganization Hemispherectomy The surgical removal of an entire cerebral hemisphere

95 Our Divided Brain Corpus callosum Corpus Callosum large band of neural fibers connects the two brain hemispheres carries messages between the hemispheres

96 Our Divided Brain The information highway from the eye to the brain

97 Split Brain a condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them

98 Split Brain What word did you see? or Look at the dot. Two words separated by a dot are momentarily projected. Point with your left hand to the word you saw.

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100 Disappearing Southpaws The percentage of left-handers decreases sharply in samples of older people (adapted from Coren, 1993). Percentage of left-handedness 14% The percentage of lefties sharply declines with age Age in years

101 Brain Structures and their Functions

102 The Endocrine System Endocrine System the body s slow chemical communication system a set of glands that secrete hormones into the bloodstream

103 Neural and Hormonal Systems Hormones chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another Pituitary Gland under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands

104 The effects of the pituitary are clearly shown here. Entertainer David Frost stands between the world s tallest and smallest man. The tallest man in history was 8 feet 11 inches tall. He died at the age of 22, partly as a result of this defect. The shortest known person was 23 inches tall when she died at the age of 19. Today s medicines can handle most of these problems if caught earlier enough, but these cases show what happen if the pituitary gland goes awry.

105 Neural and Hormonal Systems Oxytocin stimulates contractions of the uterus during labor and secretion of milk during nursing. Growth Hormone stimulates the physical development of bones and muscles.

106 Neural and Hormonal Systems Adrenal [ah-dreen-el] Glands a pair of endocrine glands just above the kidneys secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress Cortisol regulates metabolism and response to stress.

107 Neural and Hormonal Systems Pancreas Hormones Insulin decreases blood sugar Glucagon Increases blood sugar

108 Neural and Hormonal Systems Thyroid Hormone Thyroxin regulates metabolism and growth

109 Neural and Hormonal Systems Sex Glands (Gonads) Female Sex Hormone Estrogen (Ovary) Male Sex Hormone Androgen (Testis)