CHAPTER 2
:
©2004 Prentice Hall Publishing

The Body’s Communication Networks
The Neuron
The Brain
Prospects for the Future
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Body’s Communication
Networks
The Nervous System
•
Central Nervous System(CNS)
–
The network of nerves contained within the brain and spinal cord
•
Peripheral Nervous System(PNS)
–
The PNS comprises the somatic and autonomic nervous systems
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Body’s Communication
Networks
Divisions of the Nervous System
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Body’s Communication
Networks
Major Endocrine Glands
• Endocrine system :
Ductless glands that regulate growth, reproduction, metabolism, mood, and some behavior.
•
Hormones : Chemical messengers secreted into the bloodstream.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
•
Neurons
–
Nerve cells that serve as the building blocks of the nervous system
•
Sensory Neurons
–
Neurons that send signals from the senses, skin, muscles, and internal organs to the
CNS
•
Motor Neurons
– Neurons that transmit commands from the
CNS to the muscles, glands, and organs
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
The Withdrawal Reflex
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
The Neuron in Action
• Action Potential
–
An electrical impulse that surges along an axon, caused by an influx of positive ions in the neuron
•
Threshold
–
The level of stimulation needed to trigger an action potential
•
Neurotransmitters
–
Chemical messengers that transmit information by crossing the synapse from one neuron to another
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
• Impulse releases neurotransmitter from axon terminals.
•
Neurotransmitter enters synaptic gap.
•
Neurotransmitter binds to receptors on the receiving neuron.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Neuron
Neurotransmitters
Major Neurotransmitters
•
Acetylcholine (ACh)
•
Dopamine
•
Endorphins
•
Norepinephrine
•
Serotonin
•
Gamma amino butyric acid (GABA )
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Tools of Behavioral Neuroscience
•
Clinical Case Studies
•
Experimental Interventions
•
Electrical Recordings
•
Brain-Imaging Techniques
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Tools of Behavioral Neuroscience
Electroencephalogram (EEG)
•
An instrument used to measure electrical activity in the brain through electrodes placed on the scalp
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Tools of Behavioral Neuroscience
Positron Emission Tomography
–
A visual display of brain activity, as measured by the amount of glucose being used
•
Radioactive isotopes (small amounts) are placed in the blood.
•
Sensors detect radioactivity.
•
Different tasks show distinct activity patterns.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Tools of Behavioral Neuroscience
Magnetic Resonance Imaging
–
A brain-imaging technique that uses magnetic fields and radio waves to produce, clear three-dimensional images
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
•
Medulla
–
Vital involuntary functions
•
Pons
– Sleep and arousal
• Reticular formation
–
Sleep, arousal, attention
•
Cerebellum
– Motor coordination
The Brainstem
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
The Limbic System
•
Thalamus
–
Sensory relay station
•
Amygdala
–
Fear, anger, and aggression
•
Hippocampus
–
Memory formation
•
Hypothalamus
–
Regulates glands, autonomic NS
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
The Cerebral Cortex in Animals
•
The outermost covering of the brain, largely responsible for higher-order mental processes
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
The Four Lobes of the Cerebral Cortex
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
Within the Lobes of the Cerebral Cortex Are:
•
The Somatosensory Cortex
–
Receives sensory information
•
The Motor Cortex
–
Sends impulses to voluntary muscles
•
The Association Cortex
– Houses the brain’s higher mental processes
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The Somatosensory and Motor Areas
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
Regions of the Brain
Language Processing
• Broca’s Area
–
Located in the left hemisphere, directs the muscle movements in speech production
• Wernicke’s Area
–
Located in the left hemisphere, involved in the comprehension of language
The brain operates as an integrated system.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
The Split Brain
– A bundle of nerve fibers that connects the left and right hemispheres
•
If surgically severed for treatment of epilepsy, hemispheres cannot communicate directly.
The Corpus Callosum
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
The Split Brain
• Both eyes send information to both hemispheres.
•
Images in the right half of the visual field go to the left hemisphere.
•
Images in the left half of the visual field go to the right hemisphere.
Visual Processing
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
The Split Brain
Sperry’s Split-Brain Experiment
•
Split-brain subjects could not name objects shown only to the right hemisphere.
•
If asked to select these objects with their left hand, they succeeded.
•
The left hemisphere controls speech, the right does not.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
The Split Brain
The Talking Left Hemisphere
• Brighter areas indicate higher activity levels.
•
When hearing words, for example, auditory cortex and
Wernicke’s area are the most active.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

The Brain
The Split Brain
• A patient with a stroke in the right hemisphere was asked to copy the drawings.
•
Typical of neglect syndromes, the left side of the model is almost completely ignored.
Neglect Syndrome
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

Prospects for the Future
The Brain’s Capacity for Growth
& Reorganization
•
Plasticity
–
A capacity to change as a result of experience
•
Richer environments lead to heavier, thicker brains, more synapses, and better learning.
•
The cost of plasticity is the case of the phantom limb.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing

Prospects for the Future
The Brain’s Capacity for Growth
& Reorganization
•
Neurogenesis
–
The production of new brain cells
•
Neural Graft
–
Technique of transplanting healthy tissue from the nervous system of one animal into that of another
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing