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Psychology

<OpenstaxParagraph>
	The two hemispheres of the cerebral cortex are part of the <OpenstaxTerm>forebrain</OpenstaxTerm> (<a href="#CNX_Psych_03_04_FMHBrain">Figure 3.17</a>), which is the largest part of the brain. The forebrain contains the cerebral cortex and a number of other structures that lie beneath the cortex (called subcortical structures): thalamus, hypothalamus, pituitary gland, and the limbic system (a collection of structures). The cerebral cortex, which is the outer surface of the brain, is associated with higher level processes such as consciousness, thought, emotion, reasoning, language, and memory. Each cerebral hemisphere can be subdivided into four lobes, each associated with different functions.
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_FMHBrain" src="https://openstax.org/apps/archive/20240226.174525/resources/4f26a2da7a65c79c6a45dd14b1957a84752b3c2c" alt="An illustration shows the position and size of the forebrain (the largest portion), midbrain (a small central portion), and hindbrain (a portion in the lower back part of the brain)." mediaType="image/jpg" width="487" height="355" />
<OpenstaxFigureText width="487">
	Figure 3.17 The brain and its parts can be divided into three main categories: the forebrain, midbrain, and hindbrain.
</OpenstaxFigureText>
<OpenstaxH3>Lobes of the Brain</OpenstaxH3>
<OpenstaxParagraph>
	The four lobes of the brain are the frontal, parietal, temporal, and occipital lobes (<a href="#CNX_Psych_03_04_Lobes">Figure 3.18</a>). The <OpenstaxTerm>frontal lobe</OpenstaxTerm> is located in the forward part of the brain, extending back to a fissure known as the central sulcus. The frontal lobe is involved in reasoning, motor control, emotion, and language. It contains the <OpenstaxTerm>motor cortex</OpenstaxTerm>, which is involved in planning and coordinating movement; the <OpenstaxTerm>prefrontal cortex</OpenstaxTerm>, which is responsible for higher-level cognitive functioning; and <OpenstaxTerm>Broca’s area</OpenstaxTerm>, which is essential for language production.
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_Lobes" src="https://openstax.org/apps/archive/20240226.174525/resources/51350bb37f6375f3d5add77b310fafdf4236a77f" alt="An illustration shows the four lobes of the brain." mediaType="image/jpg" width="487" height="355" />
<OpenstaxFigureText width="487">
	Figure 3.18 The lobes of the brain are shown.
</OpenstaxFigureText>
<OpenstaxParagraph>
	People who suffer damage to Broca’s area have great difficulty producing language of any form (<a href="#CNX_Psych_03_04_Lobes">Figure 3.18</a>). For example, Padma was an electrical engineer who was socially active and a caring, involved parent. About twenty years ago, she was in a car accident and suffered damage to her Broca’s area. She completely lost the ability to speak and form any kind of meaningful language. There is nothing wrong with her mouth or her vocal cords, but she is unable to produce words. She can follow directions but can’t respond verbally, and she can read but no longer write. She can do routine tasks like running to the market to buy milk, but she could not communicate verbally if a situation called for it.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Probably the most famous case of frontal lobe damage is that of a man by the name of Phineas <OpenstaxTerm>Gage</OpenstaxTerm>. On September 13, 1848, Gage (age 25) was working as a railroad foreman in Vermont. He and his crew were using an iron rod to tamp explosives down into a blasting hole to remove rock along the railway’s path. Unfortunately, the iron rod created a spark and caused the rod to explode out of the blasting hole, into Gage’s face, and through his skull (<a href="#CNX_Psych_03_04_GageSkull">Figure 3.19</a>). Although lying in a pool of his own blood with brain matter emerging from his head, Gage was conscious and able to get up, walk, and speak. But in the months following his accident, people noticed that his personality had changed. Many of his friends described him as no longer being himself. Before the accident, it was said that Gage was a well-mannered, soft-spoken man, but he began to behave in odd and inappropriate ways after the accident. Such changes in personality would be consistent with loss of impulse control—a frontal lobe function.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Beyond the damage to the frontal lobe itself, subsequent investigations into the rod's path also identified probable damage to pathways between the frontal lobe and other brain structures, including the limbic system. With connections between the planning functions of the frontal lobe and the emotional processes of the limbic system severed, Gage had difficulty controlling his emotional impulses.
</OpenstaxParagraph>
<OpenstaxParagraph>
	However, there is some evidence suggesting that the dramatic changes in Gage’s personality were exaggerated and embellished. Gage's case occurred in the midst of a 19th century debate over localization—regarding whether certain areas of the brain are associated with particular functions. On the basis of extremely limited information about Gage, the extent of his injury, and his life before and after the accident, scientists tended to find support for their own views, on whichever side of the debate they fell (Macmillan, 1999).
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_GageSkull" src="https://openstax.org/apps/archive/20240226.174525/resources/33c5abdebb4d89ab785f0b3bd0ba5255f9670062" alt="Image (a) is a photograph of Phineas Gage holding a metal rod. Image (b) is an illustration of a skull with a metal rod passing through it from the cheek area to the top of the skull." mediaType="image/jpg" width="487" height="392" />
<OpenstaxFigureText width="487">
	Figure 3.19 (a) Phineas Gage holds the iron rod that penetrated his skull in an 1848 railroad construction accident. (b) Gage’s prefrontal cortex was severely damaged in the left hemisphere. The rod entered Gage’s face on the left side, passed behind his eye, and exited through the top of his skull, before landing about 80 feet away. (credit a: modification of work by Jack and Beverly Wilgus)
</OpenstaxFigureText>
<OpenstaxParagraph>
	The brain’s <OpenstaxTerm>parietal lobe</OpenstaxTerm> is located immediately behind the frontal lobe, and is involved in processing information from the body’s senses. It contains the <OpenstaxTerm>somatosensory cortex</OpenstaxTerm>, which is essential for processing sensory information from across the body, such as touch, temperature, and pain. The somatosensory cortex is an area of the brain which processes touch and sensation. The somatosensory cortex is fascinating because each different area of the cortex processes sensations from a different part of your body. Furthermore, the larger the surface area of the specific body part and the greater amount of nerves in that body part, the larger the area dedicated to processing sensation from that body part in the somatosensory cortex. For example, fingers take up a lot more space than toes. As you can notice from (<a href="#CNX_Psych_03_04_BrainOrg">Figure 3.20</a>), the amount of space to process sensation from fingers is much greater than that of toes.
</OpenstaxParagraph>
<OpenstaxNote>
	<OpenstaxNoteTitle> Link to Learning </OpenstaxNoteTitle> 
	<OpenstaxParagraph>
		One fascinating example of neuroplasticity involves reorganization of the somatosensory cortex following limb amputation. Check out this <a href="http://openstax.org/l/phantomlimb">NPR segment about amputees’ experiences of “phantom limbs” following amputation</a> to learn more.
	</OpenstaxParagraph>
</OpenstaxNote>
<OpenstaxFigure id="CNX_Psych_03_04_BrainOrg" src="https://openstax.org/apps/archive/20240226.174525/resources/cbfef70836aa80f45752e4e10291c01143071903" alt="A diagram shows the organization in the somatosensory cortex, with functions for these parts in this proximal sequential order: genitals, toes, ankles, knees, hips, trunk, shoulders, elbows, wrists, hands, fingers, thumbs, neck, eyebrows and eyelids, eyeballs, face, lips, jaw, tongue, salivation, chewing, and swallowing." mediaType="image/jpg" width="651" height="496" />
<OpenstaxFigureText width="651">
	Figure 3.20 Spatial relationships in the body are mirrored in the organization of the somatosensory cortex.
</OpenstaxFigureText>
<OpenstaxParagraph>
	The <OpenstaxTerm>temporal lobe</OpenstaxTerm> is located on the side of the head (temporal means “near the temples”), and is associated with hearing, memory, emotion, and some aspects of language. The <OpenstaxTerm>auditory cortex</OpenstaxTerm>, the main area responsible for processing auditory information, is located within the temporal lobe. <OpenstaxTerm>Wernicke’s area</OpenstaxTerm>, important for speech comprehension, is also located here. Whereas individuals with damage to Broca’s area have difficulty producing language, those with damage to Wernicke’s area can produce sensible language, but they are unable to understand it (<a href="#CNX_Psych_03_04_Broca">Figure 3.21</a>).
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_Broca" src="https://openstax.org/apps/archive/20240226.174525/resources/87586beffe69763960e4c69b0c8a860b7aa0662e" alt="An illustration shows the locations of Broca’s and Wernicke’s areas." mediaType="image/jpg" width="487" height="301" />
<OpenstaxFigureText width="487">
	Figure 3.21 Damage to either Broca’s area or Wernicke’s area can result in language deficits. The types of deficits are very different, however, depending on which area is affected.
</OpenstaxFigureText>
<OpenstaxParagraph>
	The <OpenstaxTerm>occipital lobe</OpenstaxTerm> is located at the very back of the brain, and contains the primary visual cortex, which is responsible for interpreting incoming visual information. The occipital cortex is organized retinotopically, which means there is a close relationship between the position of an object in a person’s visual field and the position of that object’s representation on the cortex. You will learn much more about how visual information is processed in the occipital lobe when you study sensation and perception.
</OpenstaxParagraph>
<OpenstaxH3>Other Areas of the Forebrain</OpenstaxH3>
<OpenstaxParagraph>
	Other areas of the <OpenstaxTerm>forebrain</OpenstaxTerm>, located beneath the cerebral cortex, include the thalamus and the limbic system. The <OpenstaxTerm>thalamus</OpenstaxTerm> is a sensory relay for the brain. All of our senses, with the exception of smell, are routed through the thalamus before being directed to other areas of the brain for processing (<a href="#CNX_Psych_03_04_Thalamus">Figure 3.22</a>).
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_Thalamus" src="https://openstax.org/apps/archive/20240226.174525/resources/8e09eea6ecb3792a4cdcf6bdbeb1f5ede8187c36" alt="An illustration shows the location of the thalamus in the brain." mediaType="imag/jpg" width="487" height="408" />
<OpenstaxFigureText width="487">
	Figure 3.22 The thalamus serves as the relay center of the brain where most senses are routed for processing.
</OpenstaxFigureText>
<OpenstaxParagraph>
	The <OpenstaxTerm>limbic system</OpenstaxTerm> is involved in processing both emotion and memory. Interestingly, the sense of smell projects directly to the limbic system; therefore, not surprisingly, smell can evoke emotional responses in ways that other sensory modalities cannot. The limbic system is made up of a number of different structures, but three of the most important are the hippocampus, the amygdala, and the hypothalamus (<a href="#CNX_Psych_03_04_Limbic">Figure 3.23</a>). The <OpenstaxTerm>hippocampus</OpenstaxTerm> is an essential structure for learning and memory. The <OpenstaxTerm>amygdala</OpenstaxTerm> is involved in our experience of emotion and in tying emotional meaning to our memories. The <OpenstaxTerm>hypothalamus</OpenstaxTerm> regulates a number of homeostatic processes, including the regulation of body temperature, appetite, and blood pressure. The hypothalamus also serves as an interface between the nervous system and the endocrine system and in the regulation of sexual motivation and behavior.
</OpenstaxParagraph>
<OpenstaxFigure id="CNX_Psych_03_04_Limbic" src="https://openstax.org/apps/archive/20240226.174525/resources/3341e952a70934c7b36cd9b8466c0df00cb96d7f" alt="An illustration shows the locations of parts of the brain involved in the limbic system: the hypothalamus, amygdala, and hippocampus." mediaType="image/jpg" width="487" height="408" />
<OpenstaxFigureText width="487">
	Figure 3.23 The limbic system is involved in mediating emotional response and memory.
</OpenstaxFigureText>
<OpenstaxH3>The Case of Henry Molaison (H.M.)</OpenstaxH3>
<OpenstaxParagraph>
	In 1953, Henry Gustav <OpenstaxTerm>Molaison</OpenstaxTerm> (H. M.) was a 27-year-old man who experienced severe seizures. In an attempt to control his seizures, H. M. underwent brain surgery to remove his hippocampus and amygdala. Following the surgery, H.M’s seizures became much less severe, but he also suffered some unexpected—and devastating—consequences of the surgery: he lost his ability to form many types of new memories. For example, he was unable to learn new facts, such as who was president of the United States. He was able to learn new skills, but afterward he had no recollection of learning them. For example, while he might learn to use a computer, he would have no conscious memory of ever having used one. He could not remember new faces, and he was unable to remember events, even immediately after they occurred. Researchers were fascinated by his experience, and he is considered one of the most studied cases in medical and psychological history (Hardt, Einarsson, &amp; Nader, 2010; Squire, 2009). Indeed, his case has provided tremendous insight into the role that the hippocampus plays in the consolidation of new learning into explicit memory.
</OpenstaxParagraph>
<OpenstaxNote>
	<OpenstaxNoteTitle> Link to Learning </OpenstaxNoteTitle> 
	<OpenstaxParagraph>
		Clive Wearing, an accomplished musician, lost the ability to form new memories when his hippocampus was damaged through illness. Check out the first few minutes of this <a href="http://openstax.org/l/wearing">documentary video about this man and his condition</a> to learn more.
	</OpenstaxParagraph>
</OpenstaxNote>

3.4.3 Forebrain Structures

1 Introduction to Psychology

1.1 What Is Psychology?

1.1.1 Why Study Psychology?

1.2 History of Psychology

1.2.1 Wundt and Structuralism

1.2.2 Functionalism

1.2.3 Freud and Psychoanalytic Theory

1.2.4 Wertheimer, Koffka, Köhler, and Gestalt Psychology

1.2.5 Pavlov, Watson, Skinner, and Behaviorism

1.2.6 Maslow, Rogers, and Humanism

1.2.7 The Cognitive Revolution

1.2.8 Multicultural And Cross-Cultural Psychology

1.2.9 Women in Psychology

1.3 Contemporary Psychology

1.3.1 Biopsychology and Evolutionary Psychology

1.3.2 Sensation and Perception

1.3.3 Cognitive Psychology

1.3.4 Developmental Psychology

1.3.5 Personality Psychology

1.3.6 Social Psychology

1.3.7 Industrial-Organizational Psychology

1.3.8 Health Psychology

1.3.9 Sport and Exercise Psychology

1.3.10 Clinical Psychology

1.3.11 Forensic Psychology

1.4 Careers in Psychology

1.4.1 Other Careers in Academic Settings

1.4.2 Career Options Outside of Academic Settings

2 Psychological Research

2.1 Why Is Research Important?

2.1.1 Use of Research Information

2.1.2 NOTABLE RESEARCHERS

2.1.3 The Process of Scientific Research

2.2 Approaches to Research

2.2.1 Clinical or Case Studies

2.2.2 Naturalistic Observation

2.2.3 Surveys

2.2.4 Archival Research

2.2.5 Longitudinal and Cross-Sectional Research

2.3 Analyzing Findings

2.3.1 Correlational Research

2.3.2 Causality: Conducting Experiments and Using the Data

2.3.3 Reliability and Validity

2.4 Ethics

2.4.1 Research Involving Human Participants

2.4.2 Research Involving Animal Subjects

3 Biopsychology

3.1 Human Genetics

3.1.1 Genetic Variation

3.1.2 Gene-Environment Interactions

3.2 Cells of the Nervous System

3.2.1 Neuron Structure

3.2.2 Neuronal Communication

3.2.3 Neurotransmitters and Drugs

3.3 Parts of the Nervous System

3.3.1 Peripheral Nervous System

3.4 The Brain and Spinal Cord

3.4.1 The Spinal Cord

3.4.2 The Two Hemispheres

3.4.4 Midbrain and Hindbrain Structures

3.4.5 Brain Imaging

3.5 The Endocrine System

3.5.1 Major Glands

4 States of Consciousness

4.1 What Is Consciousness?

4.1.1 Biological Rhythms

4.1.2 Problems With Circadian Rhythms

4.2 Sleep and Why We Sleep

4.2.1 What is Sleep?

4.2.2 Why Do We Sleep?

4.3 Stages of Sleep

4.3.1 NREM Stages of Sleep

4.3.2 REM Sleep

4.4 Sleep Problems and Disorders

4.4.1 Insomnia

4.4.2 Parasomnias

4.4.3 Sleep Apnea

4.4.4 Narcolepsy

4.5 Substance Use and Abuse

4.5.1 Substance Use Disorders

4.5.2 Drug Categories

4.6 Other States of Consciousness

4.6.1 Hypnosis

4.6.2 Meditation

5 Sensation and Perception

5.1 Sensation versus Perception

5.1.1 Sensation

5.1.2 Perception

5.2 Waves and Wavelengths

5.2.1 Amplitude and Wavelength

5.2.2 Light Waves

5.2.3 Sound Waves

5.3 Vision

5.3.1 Anatomy of the Visual System

5.3.2 Color and Depth Perception

5.4 Hearing

5.4.1 Anatomy of the Auditory System

5.4.2 Pitch Perception

5.4.3 Sound Localization

Question	Answer
structure in the limbic system involved in our experience of emotion and tying emotional meaning to our memories	amygdala
strip of cortex in the temporal lobe that is responsible for processing auditory information	auditory cortex
region in the left hemisphere that is essential for language production	Broca’s area
largest part of the brain, containing the cerebral cortex, the thalamus, and the limbic system, among other structures	forebrain
part of the cerebral cortex involved in reasoning, motor control, emotion, and language; contains motor cortex	frontal lobe
structure in the temporal lobe associated with learning and memory	hippocampus
forebrain structure that regulates sexual motivation and behavior and a number of homeostatic processes; serves as an interface between the nervous system and the endocrine system	hypothalamus
collection of structures involved in processing emotion and memory	limbic system
strip of cortex involved in planning and coordinating movement	motor cortex
part of the cerebral cortex associated with visual processing; contains the primary visual cortex	occipital lobe
part of the cerebral cortex involved in processing various sensory and perceptual information; contains the primary somatosensory cortex	parietal lobe
area in the frontal lobe responsible for higher-level cognitive functioning	prefrontal cortex
essential for processing sensory information from across the body, such as touch, temperature, and pain	somatosensory cortex
part of cerebral cortex associated with hearing, memory, emotion, and some aspects of language; contains primary auditory cortex	temporal lobe
sensory relay for the brain	thalamus
important for speech comprehension	Wernicke’s area