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Development of the Human BrainThe mental processes and behaviors studied by psychology are directly controlled by the brain, one of the most complex systems in nature. Learning Objectives Explain the structure of the major layers of the brain Key TakeawaysKey Points
Key Terms
The human brain is one of the most complex systems on earth. Every component of the brain must work together in order to keep its body functioning. The brain and the spinal cord make up the central nervous system, which alongside the peripheral nervous system is responsible for regulating all bodily functions. The central nervous system: 1. Brain 2. Brain stem 3. Spinal cord Psychology seeks to explain the mental processes and behavior of individuals by studying the interaction between mental processes and behavior on a systemic level. Therefore, the field of psychology is tightly intertwined with the study of the brain. The Structure of the BrainThe developing brain goes through many stages. In the embryos of vertebrates, the predecessor to the brain and spinal cord is the neural tube. As the fetus develops, the grooves and folds in the neural tube deepen, giving rise to different layers of the brain. The human brain is split up into three major layers: the hindbrain, the midbrain, and the forebrain. The embryonic brain: The layers of the embryonic brain. The telencephalon and diencephalon give rise to the forebrain, while the metencephalon and myelencephalon give rise to the hindbrain. HindbrainThe hindbrain is the well-protected central core of the brain. It includes the cerebellum, reticular formation, and brain stem, which are responsible for some of the most basic autonomic functions of life, such as breathing and movement. The brain stem contains the pons and medulla oblongata. Evolutionarily speaking, the hindbrain contains the oldest parts of the brain, which all vertebrates possess, though they may look different from species to species. MidbrainThe midbrain makes up part of the brain stem. It is located between the hindbrain and forebrain. All sensory and motor information that travels between the forebrain and the spinal cord passes through the midbrain, making it a relay station for the central nervous system. Forebrain The forebrain is the most anterior division of the developing vertebrate brain, containing the most complex networks in the central nervous system. The forebrain has two major divisions: the diencephalon and the telencephalon. The diencephalon is lower, containing the thalamus and hypothalamus (which together form the limbic system); the telencephalon is on top of the diencephalon and contains the cerebrum, the home of the highest-level cognitive processing in
the brain. It is the large and complicated forebrain that distinguishes the human brain from other vertebrate brains. Lower-Level StructuresThe brain's lower-level structures consist of the brain stem, the spinal cord, and the cerebellum. Learning Objectives Outline the location and functions of the lower-level structures of the brain Key TakeawaysKey Points
Key Terms
The brain's lower-level structures consist of the brain stem and spinal cord, along with the cerebellum. With the exception of the spinal cord, these structures are largely located within the hindbrain, diencephalon (or interbrain), and midbrain. These lower dorsal structures are the oldest parts of the brain, having existed for much of its evolutionary history. As such they are geared more toward basic bodily processes necessary to survival. It is the more recent layers of the brain (the forebrain) which are responsible for the higher-level cognitive functioning (language, reasoning) not strictly necessary to keep a body alive. The HindbrainThe hindbrain, which includes the medulla oblongata, the pons, and the cerebellum, is responsible some of the oldest and most primitive body functions. Each of these structures is described below. Medulla OblongataThe medulla oblongata sits at the transition zone between the brain and the spinal cord. It is the first region that formally belongs to the brain (rather than the spinal cord). It is the control center for respiratory, cardiovascular, and digestive functions. PonsThe pons connects the medulla oblongata with the midbrain region, and also relays signals from the forebrain to the cerebellum. It houses the control centers for respiration and inhibitory functions. The cerebellum is attached to the dorsal side of the pons. CerebellumThe cerebellum is a separate region of the brain located behind the medulla oblongata and pons. It is attached to the rest of the brain by three stalks (called pedunculi), and coordinates skeletal muscles to produce smooth, graceful motions. The cerebellum receives information from our eyes, ears, muscles, and joints about the body's current positioning (referred to as proprioception). It also receives output from the cerebral cortex about where these body parts should be. After processing this information, the cerebellum sends motor impulses from the brain stem to the skeletal muscles so that they can move. The main function of the cerebellum is this muscle coordination. However, it is also responsible for balance and posture, and it assists us when we are learning a new motor skill, such as playing a sport or musical instrument. Recent research shows that apart from motor functions the cerebellum also has some role in emotional sensitivity. Human and shark brains: The shark brain diverged on the evolutionary tree from the human brain, but both still have the "old" structures of the hindbrain and midbrain dedicated to autonomic bodily processes. The MidbrainThe midbrain is located between the hindbrain and forebrain, but it is actually part of the brain stem. It displays the same basic functional composition found in the spinal cord and the hindbrain. Ventral areas control motor function and convey motor information from the cerebral cortex. Dorsal regions of the midbrain are involved in sensory information circuits. The substantia nigra, a part of the brain that plays a role in reward, addiction, and movement (due to its high levels of dopaminergic neurons) is located in the midbrain. In Parkinson's disease, which is characterized by a deficit of dopamine, death of the substantia nigra is evident. The Diencephalon ("interbrain")The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to posterior forebrain structures. In adults, the diencephalon appears at the upper end of the brain stem, situated between the cerebrum and the brain stem. It is home to the limbic system, which is considered the seat of emotion in the human brain. The diencephalon is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus, and the epithalamus. ThalamusThe thalamus is part of the limbic system. It consists of two lobes of grey matter along the bottom of the cerebral cortex. Because nearly all sensory information passes through the thalamus it is considered the sensory "way station" of the brain, passing information on to the cerebral cortex (which is in the forebrain). Lesions of, or stimulation to, the thalamus are associated with changes in emotional reactivity. However, the importance of this structure on the regulation of emotional behavior is not due to the activity of the thalamus itself, but to the connections between the thalamus and other limbic-system structures. Limbic system, brain stem, and spinal cord: An image of the brain showing the limbic system in relation to the brain stem and spinal cord. HypothalamusThe hypothalamus is a small part of the brain located just below the thalamus. Lesions of the hypothalamus interfere with motivated behaviors like sexuality, combativeness, and hunger. The hypothalamus also plays a role in emotion: parts of the hypothalamus seem to be involved in pleasure and rage, while the central part is linked to aversion, displeasure, and a tendency towards uncontrollable and loud laughing. When external stimuli are presented (for example, a dangerous stimuli), the hypothalamus sends signals to other limbic areas to trigger feeling states in response to the stimuli (in this case, fear). Hypothalamus: An image of the brain showing the location of the hypothalamus. The Spinal CordThe spinal cord is a tail-like structure embedded in the vertebral canal of the spine. The adult spinal cord is about 40 cm long and weighs approximately 30 g. The spinal cord is attached to the underside of the medulla oblongata, and is organized to serve four distinct tasks:
Basic parts of the brain, part 1, 3-D anatomy tutorial: http://www.anatomyzone.com 3D anatomy tutorial on the basic parts of the brain using the Zygote Body Browser (http://www.zygotebody.com). This is the FIRST part, please watch the second part as well! Join the Facebook page for updates:
http://www.facebook.com/anatomyzone Follow me on twitter: http://www.twitter.com/anatomyzone Subscribe to the channel for more videos and updates: http://www.youtube.com/subscription_center?add_user=theanatomyzone Cerebral CortexThe cerebral cortex is the outermost layered structure of the brain and controls higher brain functions such as information processing. Learning Objectives Differentiate between the cortex and the
cerebrum Key TakeawaysKey Points
Key Terms
Cortex The cerebral cortex, the largest part of the mammalian brain, is the wrinkly gray outer covering of the cerebrum. While the cortex is less than 1/4" thick, it is here that all sensation, perception, memory, association, thought, and voluntary physical actions occur. The cerebral cortex is considered the ultimate control and information-processing center in the
brain. Lobes of the brain: A diagram of the brain identifying the different lobes by color. Counterclockwise from bottom: It contains the parietal lobe (green), the occipital lobe (red), the temporal lobe (yellow), and the frontal lobe (blue). The cortex is wrinkly in appearance.
Evolutionary constraints on skull size brought about this development; it allowed for the cortex to become larger without our brains (and therefore craniums) becoming disadvantageously large. At times it has been theorized that brain size correlated positively with intelligence; it has also been suggested that surface area of cortex (basically, "wrinkliness" of the brain) rather than brain size that correlates most directly with intelligence. Current research suggests that both of these may be
at least partially true, but the degree to which they correlate is not clear. Sulci and gyri: As depicted in this diagram of brain structures, sulci are the "valleys" and gyri are the "peaks" in the folds of the brain. Cerebrum Beneath the cerebral cortex is the cerebrum, which serves as the
main thought and control center of the brain. It is the seat of higher-level thought like emotions and decision making (as opposed to lower-level thought like balance, movement, and reflexes). Grey matter and white matter: A sagittal cross-section of a human brain showing the distinct layers of grey matter (the darker outer layer) and white matter (the lighter inner layer) in the cerebrum. Cerebral Hemispheres and Lobes of the BrainThe brain is divided into two hemispheres and four lobes, each of which specializes in a different function. Learning Objectives Outline the structure and function of the lobes and hemispheres of the brain Key TakeawaysKey Points
Key Terms
Brain LateralizationThe brain is divided into two halves, called hemispheres. There is evidence that each brain hemisphere has its own distinct functions, a phenomenon referred to as lateralization. The left hemisphere appears to dominate the functions of speech, language processing and comprehension, and logical reasoning, while the right is more dominant in spatial tasks like vision-independent object recognition (such as identifying an object by touch or another nonvisual sense). However, it is easy to exaggerate the differences between the functions of the left and right hemispheres; both hemispheres are involved with most processes. Additionally, neuroplasticity (the ability of a brain to adapt to experience) enables the brain to compensate for damage to one hemisphere by taking on extra functions in the other half, especially in young brains. Corpus CallosumThe two hemispheres communicate with one another through the corpus callosum. The corpus callosum is a wide, flat bundle of neural fibers beneath the cortex that connects the left and right cerebral hemispheres and facilitates interhemispheric communication. The corpus callosum is sometimes implicated in the cause of seizures; patients with epilepsy sometimes undergo a corpus callostomy, or the removal of the corpus callosum. The Lobes of the BrainThe brain is separated into four lobes: the frontal, temporal, occipital, and parietal lobes. Lobes of the brain: The brain is divided into four lobes, each of which is associated with different types of mental processes. Clockwise from left: The frontal lobe is in blue at the front, the parietal lobe in yellow at the top, the occipital lobe in red at the back, and the temporal lobe in green on the bottom. The Frontal LobeThe frontal lobe is associated with executive functions and motor performance. Executive functions are some of the highest-order cognitive processes that humans have. Examples include:
The frontal lobe is considered to be the moral center of the brain because it is responsible for advanced decision-making processes. It also plays an important role in retaining emotional memories derived from the limbic system, and modifying those emotions to fit socially accepted norms. The Temporal Lobe The temporal lobe is associated
with the retention of short- and long-term memories. It processes sensory input including auditory information, language comprehension, and naming. It also creates emotional responses and controls biological drives such as aggression and sexuality. Broca's and Wernicke's areas: The locations of Broca's and Wernicke's areas in the brain. The Broca's area is at the back of the frontal lobe, and the Wernicke's area is roughly where the temporal lobe and parietal lobe meet. The Occipital LobeThe occipital lobe contains most of the visual cortex and is the visual processing center of the brain. Cells on the posterior side of the occipital lobe are arranged as a spatial map of the retinal field. The visual cortex receives raw sensory information through sensors in the retina of the eyes, which is then conveyed through the optic tracts to the visual cortex. Other areas of the occipital lobe are specialized for different visual tasks, such as visuospatial processing, color discrimination, and motion perception. Damage to the primary visual cortex (located on the surface of the posterior occipital lobe) can cause blindness, due to the holes in the visual map on the surface of the cortex caused by the lesions. The Parietal Lobe The parietal lobe is associated with sensory skills. It integrates different types of
sensory information and is particularly useful in spatial processing and navigation. The parietal lobe plays an important role in integrating sensory information from various parts of the body, understanding numbers and their relations, and manipulating objects. Its also processes information related to the sense of touch. The Limbic SystemThe limbic system combines higher mental functions and primitive emotion into one system. Learning Objectives Summarize the structural elements and functions of the limbic system Key TakeawaysKey Points
Key Terms
The limbic system is a complex set of structures found on the central underside of the cerebrum, comprising inner sections of the temporal lobes and the bottom of the frontal lobe. It combines higher mental functions and primitive emotion into a single system often referred to as the emotional nervous system. It is not only responsible for our emotional lives but also our higher mental functions, such as learning and formation of memories. The limbic system is the reason that some physical things such as eating seem so pleasurable to us, and the reason why some medical conditions, such as high blood pressure, are caused by mental stress. There are several important structures within the limbic system: the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus. The limbic system: All the components of the limbic system work together to regulate some of the brain's most important processes. The AmygdalaThe amygdala is a small almond-shaped structure; there is one located in each of the left and right temporal lobes. Known as the emotional center of the brain, the amygdala is involved in evaluating the emotional valence of situations (e.g., happy, sad, scary). It helps the brain recognize potential threats and helps prepare the body for fight-or-flight reactions by increasing heart and breathing rate. The amygdala is also responsible for learning on the basis of reward or punishment. The amygdala: The figure shows the location of the amygdala from the underside (ventral view) of the human brain, with the front of the brain at the top of the image. Due to its close proximity to the hippocampus, the amygdala is involved in the modulation of memory consolidation, particularly emotionally-laden memories. Emotional arousal following a learning event influences the strength of the subsequent memory of that event, so that greater emotional arousal following a learning event enhances a person's retention of that memory. In fact, experiments have shown that administering stress hormones to individuals immediately after they learn something enhances their retention when they are tested two weeks later. The Hippocampus The hippocampus is found deep in the
temporal lobe, and is shaped like a seahorse. It consists of two horns curving back from the amygdala. Psychologists and neuroscientists dispute the precise role of the hippocampus, but generally agree that it plays an essential role in the formation of new memories about past experiences. Some researchers consider the hippocampus to be responsible for general declarative memory (memories that can be explicitly verbalized, such as memory of facts and episodic memory). Hippocampus: This image shows the horned hippocampus deep within the temporal lobe. The Thalamus and HypothalamusBoth the thalamus and hypothalamus are associated with changes in emotional reactivity. The thalamus, which is a sensory "way-station" for the rest of the brain, is primarily important due to its connections with other limbic-system structures. The hypothalamus is a small part of the brain located just below the thalamus on both sides of the third ventricle. Lesions of the hypothalamus interfere with several unconscious functions (such as respiration and metabolism) and some so-called motivated behaviors like sexuality, combativeness, and hunger. The lateral parts of the hypothalamus seem to be involved with pleasure and rage, while the medial part is linked to aversion, displeasure, and a tendency for uncontrollable and loud laughter. The Cingulate GyrusThe cingulate gyrus is located in the medial side of the brain next to the corpus callosum. There is still much to be learned about this gyrus, but it is known that its frontal part links smells and sights with pleasant memories of previous emotions. This region also participates in our emotional reaction to pain and in the regulation of aggressive behavior. The Basal GangliaThe basal ganglia is a group of nuclei lying deep in the subcortical white matter of the frontal lobes that organizes motor behavior. The caudate, putamen, and globus pallidus are major components of the basal ganglia. The basal ganglia appears to serve as a gating mechanism for physical movements, inhibiting potential movements until they are fully appropriate for the circumstances in which they are to be executed. The basal ganglia is also involved with:
NeuroplasticityNeuroplasticity is the brain's ability to create new neural pathways to account for learning and acquisition of new experiences. Learning Objectives Explain how neuroplasticity occurs Key TakeawaysKey Points
Key Terms
Neuroplasticity The brain is constantly adapting throughout a lifetime, though sometimes over critical, genetically determined periods of time. Neuroplasticity is the brain's ability to create new neural pathways based on new experiences. It refers to changes in neural pathways and synapses that result from changes in behavior, environmental and neural processes, and changes resulting from bodily injury. Neuroplasticity has
replaced the formerly held theory that the brain is a physiologically static organ, and explores how the brain changes throughout life. Synaptic Pruning "Synaptic (or neuronal or axon ) pruning" refers to neurological regulatory processes that facilitate changes in neural structure by reducing the overall number of neurons and synapses, leaving more efficient synaptic configurations. At birth, there are approximately 2,500 synapses in the
cerebral cortex of a human baby. By three years old, the cerebral cortex has about 15,000 synapses. Since the infant brain has such a large capacity for growth, it must eventually be pruned down to remove unnecessary neuronal structures from the brain. This process of pruning is referred to as apoptosis, or programmed cell death. As the human brain develops, the need for more complex neuronal associations becomes much more pertinent, and simpler associations formed at childhood are replaced by
more intricately interconnected structures. Neuron growth: Neurons grow throughout adolescence and then are pruned down based on the connections that get the most use. Synaptic pruning is distinct from the regressive events seen during older age. While developmental pruning is experience-dependent, the deteriorating connections that occur with old age are not. Synaptic pruning is like carving a statue: getting the unformed stone into its best form. Once the statue is complete, the weather will begin to erode the statue,
which represents the lost connections that occur with old age. Licenses and AttributionsCC licensed content, Shared previously
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Which part of the brain plays the greatest role in controlling higher mental functions quizlet?The parts of the cerebral cortex, located at the front of the cerebral hemispheres, that are considered the "executive center" of the brain because of their role in higher mental functions.
What brain region is responsible for learning memory and personality?Collectively, your cerebral cortex is responsible for the higher-level processes of the human brain, including language, memory, reasoning, thought, learning, decision-making, emotion, intelligence and personality.
What part of the brain is responsible for cognition quizlet?The cerebral association areas are responsible for cognition.
What is the neural center of the limbic system?Hippocampus: A neural center located in the limbic system; helps process explicit memories for storage.
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The part of the brain that primarily governs higher-order mental processes is the:
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