Learning objectives
By the end of this section, you will be able to:
- Explain the functions of the spinal cord
- Identify the hemispheres and lobes of the brain
- Describe the types of techniques available to clinicians and researchers to image or scan the brain
The brain is a remarkably complex organ comprised of billions of interconnected neurons and glia. It is a bilateral, or two-sided, structure that can be separated into distinct lobes. Each lobe is associated with certain types of functions, but, ultimately, all of the areas of the brain interact with one another to provide the foundation for our thoughts and behaviors. In this section, we discuss the overall organization of the brain and the functions associated with different brain areas, beginning with what can be seen as an extension of the brain, the spinal cord.
The Spinal Cord
It can be said that the spinal cord is what connects the brain to the outside world. Because of it, the brain can act. The spinal cord is like a relay station, but a very smart one. It not only routes messages to and from the brain, but it also has its own system of automatic processes, called reflexes.
The top of the spinal cord is a bundle of nerves that merges with the brain stem, where the basic processes of life are controlled, such as breathing and digestion. In the opposite direction, the spinal cord ends just below the ribs—contrary to what we might expect, it does not extend all the way to the base of the spine.
The spinal cord is functionally organized in 30 segments, corresponding with the vertebrae. Each segment is connected to a specific part of the body through the peripheral nervous system. Nerves branch out from the spine at each vertebra. Sensory nerves bring messages in; motor nerves send messages out to the muscles and organs. Messages travel to and from the brain through every segment.
Some sensory messages are immediately acted on by the spinal cord, without any input from the brain. Withdrawal from a hot object and the knee jerk are two examples. When a sensory message meets certain parameters, the spinal cord initiates an automatic reflex. The signal passes from the sensory nerve to a simple processing center, which initiates a motor command. Seconds are saved, because messages don’t have to go to the brain, be processed, and get sent back. In matters of survival, the spinal reflexes allow the body to react extraordinarily fast.
The spinal cord is protected by bony vertebrae and cushioned in cerebrospinal fluid, but injuries still occur. When the spinal cord is damaged in a particular segment, all lower segments are cut off from the brain, causing paralysis. Therefore, the lower on the spine damage occurs, the fewer functions an injured individual will lose.
Neuroplasticity
Bob Woodruff, a reporter for ABC, suffered a traumatic brain injury after a bomb exploded next to the vehicle he was in while covering a news story in Iraq. As a consequence of these injuries, Woodruff experienced many cognitive deficits including difficulties with memory and language. However, over time and with the aid of intensive amounts of cognitive and speech therapy, Woodruff has shown an incredible recovery of function (Fernandez, 2008, October 16).
One of the factors that made this recovery possible was neuroplasticity. Neuroplasticity refers to how the nervous system can change and adapt. Neuroplasticity can occur in a variety of ways including personal experiences, developmental processes, or, as in Woodruff's case, in response to some sort of damage or injury that has occurred. Neuroplasticity can involve creation of new synapses, pruning of synapses that are no longer used, changes in glial cells, and even the birth of new neurons. Because of neuroplasticity, our brains are constantly changing and adapting, and while our nervous system is most plastic when we are very young, as Woodruff's case suggests, it is still capable of remarkable changes later in life.
The Two Hemispheres
The surface of the brain, known as the cerebral cortex, is very uneven, characterized by a distinctive pattern of folds or bumps, known as gyri (singular: gyrus), and grooves, known as sulci (singular: sulcus), shown in CNX_Psych_03_04_Cortex. These gyri and sulci form important landmarks that allow us to separate the brain into functional centers. The most prominent sulcus, known as the longitudinal fissure, is the deep groove that separates the brain into two halves or hemispheres: the left hemisphere and the right hemisphere.
View original figure (external; image not reproduced in this text edition)
Original figure description: An illustration of the brain’s exterior surface shows the ridges and depressions, and the deep fissure that runs through the center.
There is evidence of specialization of function—referred to as lateralization—in each hemisphere, mainly regarding differences in language functions. The left hemisphere controls the right half of the body, and the right hemisphere controls the left half of the body. Decades of research on lateralization of function by Michael Gazzaniga and his colleagues suggest that a variety of functions ranging from cause-and-effect reasoning to self-recognition may follow patterns that suggest some degree of hemispheric dominance (Gazzaniga, 2005). For example, the left hemisphere has been shown to be superior for forming associations in memory, selective attention, and positive emotions. The right hemisphere, on the other hand, has been shown to be superior in pitch perception, arousal, and negative emotions (Ehret, 2006). However, it should be pointed out that research on which hemisphere is dominant in a variety of different behaviors has produced inconsistent results, and therefore, it is probably better to think of how the two hemispheres interact to produce a given behavior rather than attributing certain behaviors to one hemisphere versus the other (Banich & Heller, 1998).
The two hemispheres are connected by a thick band of neural fibers known as the corpus callosum, consisting of about 200 million axons. The corpus callosum allows the two hemispheres to communicate with each other and allows for information being processed on one side of the brain to be shared with the other side.
Normally, we are not aware of the different roles that our two hemispheres play in day-to-day functions, but there are people who come to know the capabilities and functions of their two hemispheres quite well. In some cases of severe epilepsy, doctors elect to sever the corpus callosum as a means of controlling the spread of seizures (CNX_Psych_03_04_CorpusCall). While this is an effective treatment option, it results in individuals who have "split brains." After surgery, these split-brain patients show a variety of interesting behaviors. For instance, a split-brain patient is unable to name a picture that is shown in the patient’s left visual field because the information is only available in the largely nonverbal right hemisphere. However, they are able to recreate the picture with their left hand, which is also controlled by the right hemisphere. When the more verbal left hemisphere sees the picture that the hand drew, the patient is able to name it (assuming the left hemisphere can interpret what was drawn by the left hand).
View original figure (external; image not reproduced in this text edition)
Original figure description: Illustrations (a) and (b) show the corpus callosum’s location in the brain in front and side views. Photograph (c) shows the corpus callosum in a dissected brain.
Much of what we know about the functions of different areas of the brain comes from studying changes in the behavior and ability of individuals who have suffered damage to the brain. For example, researchers study the behavioral changes caused by strokes to learn about the functions of specific brain areas. A stroke, caused by an interruption of blood flow to a region in the brain, causes a loss of brain function in the affected region. The damage can be in a small area, and, if it is, this gives researchers the opportunity to link any resulting behavioral changes to a specific area. The types of deficits displayed after a stroke will be largely dependent on where in the brain the damage occurred.
Consider Theona, an intelligent, self-sufficient woman, who is 62 years old. Recently, she suffered a stroke in the front portion of her right hemisphere. As a result, she has great difficulty moving her left leg. (As you learned earlier, the right hemisphere controls the left side of the body; also, the brain’s main motor centers are located at the front of the head, in the frontal lobe.) Theona has also experienced behavioral changes. For example, while in the produce section of the grocery store, she sometimes eats grapes, strawberries, and apples directly from their bins before paying for them. This behavior—which would have been very embarrassing to her before the stroke—is consistent with damage in another region in the frontal lobe—the prefrontal cortex, which is associated with judgment, reasoning, and impulse control.
Forebrain Structures
The two hemispheres of the cerebral cortex are part of the forebrain (CNX_Psych_03_04_FMHBrain), 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.
View original figure (external; image not reproduced in this text edition)
Original figure description: 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).
Lobes of the Brain
The four lobes of the brain are the frontal, parietal, temporal, and occipital lobes (CNX_Psych_03_04_Lobes). The frontal lobe 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 motor cortex, which is involved in planning and coordinating movement; the prefrontal cortex, which is responsible for higher-level cognitive functioning; and Broca’s area, which is essential for language production.
View original figure (external; image not reproduced in this text edition)
Original figure description: An illustration shows the four lobes of the brain.
People who suffer damage to Broca’s area have great difficulty producing language of any form (CNX_Psych_03_04_Lobes). 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.
Probably the most famous case of frontal lobe damage is that of a man by the name of Phineas Gage. 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 (CNX_Psych_03_04_GageSkull). 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.
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.
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).
View original figure (external; image not reproduced in this text edition)
Original figure description: 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.
The brain’s parietal lobe is located immediately behind the frontal lobe, and is involved in processing information from the body’s senses. It contains the somatosensory cortex, 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 (CNX_Psych_03_04_BrainOrg), the amount of space to process sensation from fingers is much greater than that of toes.
View original figure (external; image not reproduced in this text edition)
Original figure description: 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.
The temporal lobe 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 auditory cortex, the main area responsible for processing auditory information, is located within the temporal lobe. Wernicke’s area, 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 (CNX_Psych_03_04_Broca).
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Original figure description: An illustration shows the locations of Broca’s and Wernicke’s areas.
The occipital lobe 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.
Other Areas of the Forebrain
Other areas of the forebrain, located beneath the cerebral cortex, include the thalamus and the limbic system. The thalamus 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 (CNX_Psych_03_04_Thalamus).
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Original figure description: An illustration shows the location of the thalamus in the brain.
The limbic system 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 (CNX_Psych_03_04_Limbic). The hippocampus is an essential structure for learning and memory. The amygdala is involved in our experience of emotion and in tying emotional meaning to our memories. The hypothalamus 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.
View original figure (external; image not reproduced in this text edition)
Original figure description: An illustration shows the locations of parts of the brain involved in the limbic system: the hypothalamus, amygdala, and hippocampus.
The Case of Henry Molaison (H.M.)
In 1953, Henry Gustav Molaison (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, & 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.
Midbrain and Hindbrain Structures
The midbrain is comprised of structures located deep within the brain, between the forebrain and the hindbrain. The reticular formation is centered in the midbrain, but it actually extends up into the forebrain and down into the hindbrain. The reticular formation is important in regulating the sleep/wake cycle, arousal, alertness, and motor activity.
The substantia nigra (Latin for “black substance”) and the ventral tegmental area (VTA) are also located in the midbrain (CNX_Psych_03_04_Midbrain). Both regions contain cell bodies that produce the neurotransmitter dopamine, and both are critical for movement. Degeneration of the substantia nigra and VTA is involved in Parkinson’s disease. In addition, these structures are involved in mood, reward, and addiction (Berridge & Robinson, 1998; Gardner, 2011; George, Le Moal, & Koob, 2012).
View original figure (external; image not reproduced in this text edition)
Original figure description: An illustration shows the location of the substantia nigra and VTA in the brain.
The hindbrain is located at the back of the head and looks like an extension of the spinal cord. It contains the medulla, pons, and cerebellum (CNX_Psych_03_04_Hindbrain). The medulla controls the automatic processes of the autonomic nervous system, such as breathing, blood pressure, and heart rate. The word pons literally means “bridge,” and as the name suggests, the pons serves to connect the hindbrain to the rest of the brain. It also is involved in regulating brain activity during sleep. The medulla, pons, and various structures are known as the brainstem, and aspects of the brainstem span both the midbrain and the hindbrain.
View original figure (external; image not reproduced in this text edition)
Original figure description: An illustration shows the location of the pons, medulla, and cerebellum.
The cerebellum (Latin for “little brain”) receives messages from muscles, tendons, joints, and structures in our ear to control balance, coordination, movement, and motor skills. The cerebellum is also thought to be an important area for processing some types of memories. In particular, procedural memory, or memory involved in learning and remembering how to perform tasks, is thought to be associated with the cerebellum. Recall that H. M. was unable to form new explicit memories, but he could learn new tasks. This is likely due to the fact that H. M.’s cerebellum remained intact.
Brain Imaging
You have learned how brain injury can provide information about the functions of different parts of the brain. Increasingly, however, we are able to obtain that information using brain imaging techniques on individuals who have not suffered brain injury. In this section, we take a more in-depth look at some of the techniques that are available for imaging the brain, including techniques that rely on radiation, magnetic fields, or electrical activity within the brain.
Techniques Involving Radiation
A computerized tomography (CT) scan involves taking a number of x-rays of a particular section of a person’s body or brain (CNX_Psych_03_04_CT). The x-rays pass through tissues of different densities at different rates, allowing a computer to construct an overall image of the area of the body being scanned. A CT scan is often used to determine whether someone has a tumor or significant brain atrophy.
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Original figure description: Image (a) shows a brain scan where the brain matter’s appearance is fairly uniform. Image (b) shows a section of the brain that looks different from the surrounding tissue and is labeled “tumor.”
Positron emission tomography (PET) scans create pictures of the living, active brain (CNX_Psych_03_04_PET). An individual receiving a PET scan drinks or is injected with a mildly radioactive substance, called a tracer. Once in the bloodstream, the amount of tracer in any given region of the brain can be monitored. As a brain area becomes more active, more blood flows to that area. A computer monitors the movement of the tracer and creates a rough map of active and inactive areas of the brain during a given behavior. PET scans show little detail, are unable to pinpoint events precisely in time, and require that the brain be exposed to radiation; therefore, this technique has been replaced by the fMRI as an alternative diagnostic tool. However, combined with CT, PET technology is still being used in certain contexts. For example, CT/PET scans allow better imaging of the activity of neurotransmitter receptors and open new avenues in schizophrenia research. In this hybrid CT/PET technology, CT contributes clear images of brain structures, while PET shows the brain’s activity.
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Original figure description: A brain scan shows different parts of the brain in different colors.
Techniques Involving Magnetic Fields
In magnetic resonance imaging (MRI), a person is placed inside a machine that generates a strong magnetic field. The magnetic field causes the hydrogen atoms in the body’s cells to move. When the magnetic field is turned off, the hydrogen atoms emit electromagnetic signals as they return to their original positions. Tissues of different densities give off different signals, which a computer interprets and displays on a monitor. Functional magnetic resonance imaging (fMRI) operates on the same principles, but it shows changes in brain activity over time by tracking blood flow and oxygen levels. The fMRI provides more detailed images of the brain’s structure, as well as better accuracy in time, than is possible in PET scans (CNX_Psych_03_04_fMRI). With their high level of detail, MRI and fMRI are often used to compare the brains of healthy individuals to the brains of individuals diagnosed with psychological disorders. This comparison helps determine what structural and functional differences exist between these populations.
View original figure (external; image not reproduced in this text edition)
Original figure description: A brain scan shows brain tissue in gray with some small areas highlighted red.
Techniques Involving Electrical Activity
In some situations, it is helpful to gain an understanding of the overall activity of a person’s brain, without needing information on the actual location of the activity. Electroencephalography (EEG) serves this purpose by providing a measure of a brain’s electrical activity. An array of electrodes is placed around a person’s head (CNX_Psych_03_04_EEG). The signals received by the electrodes result in a printout of the electrical activity of their brain, or brainwaves, showing both the frequency (number of waves per second) and amplitude (height) of the recorded brainwaves, with an accuracy within milliseconds. Such information is especially helpful to researchers studying sleep patterns among individuals with sleep disorders.
View original figure (external; image not reproduced in this text edition)
Original figure description: A photograph depicts a person looking at a computer screen and using the keyboard and mouse. The person wears a white cap covered in electrodes and wires.
Summary
The brain consists of two hemispheres, each controlling the opposite side of the body. Each hemisphere can be subdivided into different lobes: frontal, parietal, temporal, and occipital. In addition to the lobes of the cerebral cortex, the forebrain includes the thalamus (sensory relay) and limbic system (emotion and memory circuit). The midbrain contains the reticular formation, which is important for sleep and arousal, as well as the substantia nigra and ventral tegmental area. These structures are important for movement, reward, and addictive processes. The hindbrain contains the structures of the brainstem (medulla, pons, and midbrain), which control automatic functions like breathing and blood pressure. The hindbrain also contains the cerebellum, which helps coordinate movement and certain types of memories.
Individuals with brain damage have been studied extensively to provide information about the role of different areas of the brain, and recent advances in technology allow us to glean similar information by imaging brain structure and function. These techniques include CT, PET, MRI, fMRI, and EEG.
Review Questions
The ________ is a sensory relay station where all sensory information, except for smell, goes before being sent to other areas of the brain for further processing.
- amygdala
- hippocampus
- hypothalamus
- thalamus
D
Damage to the ________ disrupts one’s ability to comprehend language, but it leaves one’s ability to produce words intact.
- amygdala
- Broca’s Area
- Wernicke’s Area
- occipital lobe
C
A(n) ________ uses magnetic fields to create pictures of a given tissue.
- EEG
- MRI
- PET scan
- CT scan
B
Which of the following is not a structure of the forebrain?
- thalamus
- hippocampus
- amygdala
- substantia nigra
D
Critical Thinking Questions
Before the advent of modern imaging techniques, scientists and clinicians relied on autopsies of people who suffered brain injury with resultant change in behavior to determine how different areas of the brain were affected. What are some of the limitations associated with this kind of approach?
The same limitations associated with any case study would apply here. In addition, it is possible that the damage caused changes in other areas of the brain, which might contribute to the behavioral deficits. Such changes would not necessarily be obvious to someone performing an autopsy, as they may be functional in nature, rather than structural.
Which of the techniques discussed would be viable options for you to determine how activity in the reticular formation is related to sleep and wakefulness? Why?
The most viable techniques are fMRI and PET because of their ability to provide information about brain activity and structure simultaneously.
Personal Application Questions
You read about H. M.’s memory deficits following the bilateral removal of his hippocampus and amygdala. Have you encountered a character in a book, television program, or movie that suffered memory deficits? How was that character similar to and different from H. M.?
Glossary
- amygdala
- structure in the limbic system involved in our experience of emotion and tying emotional meaning to our memories
- auditory cortex
- strip of cortex in the temporal lobe that is responsible for processing auditory information
- Broca’s area
- region in the left hemisphere that is essential for language production
- cerebellum
- hindbrain structure that controls our balance, coordination, movement, and motor skills, and it is thought to be important in processing some types of memory
- cerebral cortex
- surface of the brain that is associated with our highest mental capabilities
- computerized tomography (CT) scan
- imaging technique in which a computer coordinates and integrates multiple x-rays of a given area
- corpus callosum
- thick band of neural fibers connecting the brain’s two hemispheres
- electroencephalography (EEG)
- recording the electrical activity of the brain via electrodes on the scalp
- forebrain
- largest part of the brain, containing the cerebral cortex, the thalamus, and the limbic system, among other structures
- frontal lobe
- part of the cerebral cortex involved in reasoning, motor control, emotion, and language; contains motor cortex
- functional magnetic resonance imaging (fMRI)
- MRI that shows changes in metabolic activity over time
- gyrus
- (plural: gyri) bump or ridge on the cerebral cortex
- hemisphere
- left or right half of the brain
- hindbrain
- division of the brain containing the medulla, pons, and cerebellum
- hippocampus
- structure in the temporal lobe associated with learning and memory
- hypothalamus
- 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
- lateralization
- concept that each hemisphere of the brain is associated with specialized functions
- limbic system
- collection of structures involved in processing emotion and memory
- longitudinal fissure
- deep groove in the brain’s cortex
- magnetic resonance imaging (MRI)
- magnetic fields used to produce a picture of the tissue being imaged
- medulla
- hindbrain structure that controls automated processes like breathing, blood pressure, and heart rate
- midbrain
- division of the brain located between the forebrain and the hindbrain; contains the reticular formation
- motor cortex
- strip of cortex involved in planning and coordinating movement
- Nodes of Ranvier
- open spaces that are found in the myelin sheath that encases the axon
- occipital lobe
- part of the cerebral cortex associated with visual processing; contains the primary visual cortex
- parietal lobe
- part of the cerebral cortex involved in processing various sensory and perceptual information; contains the primary somatosensory cortex
- pons
- hindbrain structure that connects the brain and spinal cord; involved in regulating brain activity during sleep
- positron emission tomography (PET) scan
- involves injecting individuals with a mildly radioactive substance and monitoring changes in blood flow to different regions of the brain
- prefrontal cortex
- area in the frontal lobe responsible for higher-level cognitive functioning
- reticular formation
- midbrain structure important in regulating the sleep/wake cycle, arousal, alertness, and motor activity
- somatosensory cortex
- essential for processing sensory information from across the body, such as touch, temperature, and pain
- substantia nigra
- midbrain structure where dopamine is produced; involved in control of movement
- sulcus
- (plural: sulci) depressions or grooves in the cerebral cortex
- temporal lobe
- part of cerebral cortex associated with hearing, memory, emotion, and some aspects of language; contains primary auditory cortex
- thalamus
- sensory relay for the brain
- ventral tegmental area (VTA)
- midbrain structure where dopamine is produced: associated with mood, reward, and addiction
- Wernicke’s area
- important for speech comprehension