Chapter 4: The Nervous System PDF

Chapter 4: The Nervous System  Introduction The Nervous System Central nervous system (CNS) Brain and spinal cord Peripheral nervous system (PNS) Somatic nervous system (SNS) Consists of the nerve fibers that connec...

Chapter 4: The Nervous System  Introduction The Nervous System Central nervous system (CNS) Brain and spinal cord Peripheral nervous system (PNS) Somatic nervous system (SNS) Consists of the nerve fibers that connect to your skin, muscles, and joints. Autonomic nervous system (ANS) Regulates the functions of organs and glands. breathing, heartbeat, dilation of your pupils. Sympathetic Activates your body by interacting with your various organs and glands (fight or flight) Parasympathetic Calms body back down (rest and digest) Gaskin, Behavioral Neuropsychology, 1e. © SAGE 2 Publications, 2021.  Module 4.2 The Fully Developed Brain Learning Objectives 4.2.1 Identify the major structures of the telencephalon and some of their functions. 4.2.2 Identify the major structures of the diencephalon and some of their functions. 4.2.3 Identify the major structures of the midbrain and the hindbrain and some of their functions. 4.2.4 Describe the structure of the spinal cord and how it transmits information to and from the brain. 4.2.5 Describe the different protective layers of the brain and how they work. 4.2.6 Explain how each hemisphere of the brain is associated with different functions. Gaskin, Behavioral Neuroscience: essentials and beyond 1e. © SAGE Publications, 2021. 3  Module 4.2 The Fully Developed Brain Learning Objectives 4.2.1 Identify the major structures of the telencephalon and some of their functions. 4.2.2 Identify the major structures of the diencephalon and some of their functions. 4.2.3 Identify the major structures of the midbrain and the hindbrain and some of their functions. 4.2.4 Describe the structure of the spinal cord and how it transmits information to and from the brain. 4.2.5 Describe the different protective layers of the brain and how they work. 4.2.6 Explain how each hemisphere of the brain is associated with different functions. Gaskin, Behavioral Neuroscience: essentials and beyond 1e. © SAGE Publications, 2021. 4  4.2 The Fully Developed Brain 4.2.1 The Structures and Functions of the Forebrain Brain’s relative size differ among species. Functions of the circumvolutions May be to augment the surface area of the cortex. More neurons can be packed into a highly circumvoluted brain, such as that of humans, monkeys, and chimpanzees, than in the brains of armadillos, cats, rats, and rabbits. How do Gyri and sulci develop? Three hypotheses Gyri are regions that grow at a high rate and rise above the sulci. Axons of neurons pull interconnected cortical areas closer together, giving rise to the gyri. Gray matter (areas consisting of cell bodies) grows faster than white matter (nerve fibers). This results in gray matter being compressed, making it accumulate in the mounds we recognize as gyri. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 5 Publications, 2021.  4.2 The Fully Developed Brain 4.2.1 The Structures and Functions of the Forebrain: The Forebrain (Telencephalon) The Frontal Lobes Executive functions Planning, judgment, attention, problem solving, working memory, and decision making, behavioral inhibition, processing emotions. Left frontal lobe Contains the area responsible for speech production, known as Broca’s area. Primary motor cortex (precentral gyrus, M1) Responsible for moving the body. The primary motor cortex is organized into a topographic map of the body. Mirror neurons Neurons in the premotor cortex that are activated when performing an action or when watching another individual perform the same action. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 6 Publications, 2021.  4.2 The Fully Developed Brain 4.2.1 The Structures and Functions of the Forebrain: The Forebrain (Telencephalon) The parietal lobes Contains the primary somatosensory cortex, or S1. Contains a homunculus. Responsible for sensations of touch, pressure, pain, and temperature. Proprioception The ability to know the relative position of one’s own body parts. The temporal lobes Primary auditory cortex The front-most part of the temporal lobes contains wernicke’s area, Important for understanding language Information about language acquired by wernicke’s area is relayed to broca’s area for the proper production of speech. People with damage to wernicke’s area suffer from wernicke’s aphasia. Important for memory and the recognition of objects. The occipital lobes Primary visual cortex, or V1. Where visual information is first analyzed Ocular dominance columns Some cells were activated when lines of a particular orientation were presented to the cats on a screen, and other cells were activated Gaskin, Behavioral Neuroscience: essentials and when lines of a particular orientation and moving in a particular direction. beyond 1e. © SAGE Publications, 2021. 7  4.2 The Fully Developed Brain 4.2.1 The Structures and Functions of the Forebrain: Subcortical Structures The Basal Ganglia Consist of several nuclei Dorsal striatum (caudate and putamen), the ventral striatum (includes the nucleus accumbens), substantia nigra. Involved in the smooth execution of movement and in the selection of appropriate actions. Habit learning Parkinson’s disease Neurons in the substantia nigra die, depriving the dorsal striatum of its dopaminergic inputs. The Hippocampus known to play an important role in memory. People and animals with damage to the hippocampus Trouble acquiring, storing, and retrieving certain types of memories Important for successfully navigating in and learning about one’s spatial environment Place cells The Amygdala Deeply interconnected with the hippocampus. Known for its involvement in processing emotions. People and animals with damage to the amygdala. Do not process emotions normally. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 8 Publications, 2021.  4.2 The Fully Developed Brain 4.2.2 The Structures and Functions of the Forebrain: The Diencephalon The Thalamus Acts as a relay station between sensory receptors and the brain areas responsible for interpreting those sensations. Important for a range of other functions, such as movement, the regulation of sleep- wake cycles Subdivided into several nuclei, each involved in certain functions. The hypothalamus Regulates many of the body’s functions. It is the major player in homeostasis The tendency of biological systems to maintain a stable internal environment in response to stimuli that challenge stability. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 9 Publications, 2021.  4.2 The Fully Developed Brain 4.2.3 The Midbrain and the Hindbrain Tectum Subdivided in two areas Superior colliculus Optic tectum because it plays an important role in controlling eye movements. Superior colliculus Processes auditory information. Tegmentum Plays an important role in movement and reward. Houses the substantia nigra and the ventral- tegmental area. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 10 Publications, 2021.  4.2 The Fully Developed Brain 4.2.3 The Midbrain and the Hindbrain: The Hindbrain The cerebellum Is important for motor coordination People with damage to the cerebellum cannot properly adjust their ongoing movements or coordinate their limbs very well. Involved in learning automatic motor responses. Important role in organizing and coordinating thoughts. The pons Relays signals between the cortex and the cerebellum. Involved in consciousness, sleep, and arousal. The medulla Regulates vital functions such as breathing and heartbeat. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 11 Publications, 2021.  4.2 The Fully Developed Brain 4.2.4 The Spinal Cord The Spinal Cord the other part of the central nervous system that, like the brain, is encased in bone. runs up and down your back, protected by your vertebrae. It enters the skull through a large hole at its base, called the foramen magnum, where it connects to the medulla. Foramen magnum hole at the base of the skull through which the spinal cord passes. Functions of the spinal cord carries messages from your brain to your body. It can also function independently of your brain, e.g. in the execution of reflexes. Division of the spinal cord: 33 segments 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 3 coccygeal. Dermatome An area of the skin that is connected to a spinal nerve Gaskin, Behavioral Neuropsychology, 1e. © SAGE 12 Publications, 2021.  4.2 The Fully Developed Brain 4.2.4 The Spinal Cord Dorsal nerve roots Where sensory nerve fibers enter the spinal cord, carrying information to the brain. Ventral nerve roots Area where motor nerve fibers exit the spinal cord carrying information from the brain to the body. Ascending fibers Nerves through which sensory information travels to the brain. Descending fibers Nerves that carry information from the brain. Upper motor neurons Motor neurons that carry information from the brain. Lower motor neurons Motor neurons that innervate the muscles. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 13 Publications, 2021.  4.2 The Fully Developed Brain 4.2.4 The Spinal Cord Paraplegia Loss of the use of and sensation in the lower limbs that results from damage to the lower parts of the spinal cord. Quadriplegia (also known as tetraplegia) Loss of the use of and sensation in both upper and lower limbs that results from damage to the upper spinal cord. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 14 Publications, 2021.  4.2 The Fully Developed Brain 4.2.5 The Protected Brain The meninges Three membranes that envelop the brain (and spinal cord) The pia mater, the arachnoid mater, and the dura mater. The cerebrospinal fluid Fluid that cushions the brain and spinal cord. The blood–brain barrier The protective barrier formed by the cells of the brain’s blood vessels, which block or slow the passage of harmful molecules to the brain. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 15 Publications, 2021.  4.2 The Fully Developed Brain 4.2.6 Hemispheric Specialization Corpus callosum thick bundle of nerve fibers used to send information from one hemisphere to the other. Hemispheric asymmetry Some functions are associated with either the right or left hemisphere. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 16 Publications, 2021.  4.2 The Fully Developed Brain 4.2.6 Hemispheric Specialization Cerebral Dominance Broca observed that there was a relationship between handedness and the speech area in the brain. The hemisphere that contained the language area became known as the dominant hemisphere. Split-Brain Patients Patients who have been subjected to the removal of the corpus callosum. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 17 Publications, 2021.  Module 4.2 Test Yourself 4.2.1 Name the structures of the telencephalon and explain their functions. 4.2.2 Name the structures of the diencephalon and explain their functions. 4.2.3 Name the structures of the mesencephalon, metencephalon, and myelencephalon and explain their functions. 4.2.4 Explain the structure of the spinal cord, how it is involved in the transmission of information, and the effects of spinal cord damage. 4.2.5 Name and explain the three different levels at which the brain is protected. 4.2.6 What are some of the differences in the way the left and right hemispheres process information? Gaskin, Behavioral Neuroscience: essentials and beyond 1e. © SAGE Publications, 2021. 18  Module 4.3 The Peripheral Nervous System Learning Objectives 4.3.1 Explain the functions of the somatic nervous system. 4.3.2 Explain the functions of the autonomic nervous system. Gaskin, Behavioral Neuroscience: essentials and beyond 1e. © SAGE Publications, 2021. 19  4.3 The Peripheral Nervous System The peripheral nervous system (PNS) Consists of the parts of the nervous system that are outside of the central nervous system. Somatic nervous system (SNS) The part of the PNS that is responsible for the voluntary control of movement. It consists of a collection of nerve fibers that enter and exit the spinal cord. Sensory neurons convey sensory information from your skin, muscles, joints, tendons, blood vessels, and organs. Sensory neurons, also known as afferent neurons, enter the back of the spinal cord through the dorsal roots. Motor neurons, also known as efferent neurons, move your muscles and exit the front of the spinal cord through the ventral roots. Patellar reflex autonomic nervous systems (ANS). Reflex arc A loop of information that begins with the activation of sensory neurons and ends with muscle contraction, through the activation of motor neurons. CNS and PNS Functionally and physiologically interrelated. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 20 Publications, 2021.  4.3 The Peripheral Nervous System 4.3.2 The Autonomic Nervous System Involuntary muscles Muscles that are not under conscious control. Sympathetic nervous system Gets your body ready for action; often referred to as the “fight-or-flight” system. Parasympathetic nervous system Counters the activity of the sympathetic nervous system by slowing things down; often referred to as the “rest-and-digest” system. Ganglia A collection of cell bodies. Preganglionic fibers Fibers that exit the spinal cord and enter ganglia. Postganglionic fibers Fibers that exit ganglia and enter the spinal cord. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 21 Publications, 2021.  4.3 The Peripheral Nervous System 4.3.2 The Autonomic Nervous System: The Cranial Nerves The cranial nerves 12 pairs. Each is given a name and a number. Some nerves transmit information from the senses. Other cranial nerves are involved in movement Vagus nerve The cranial nerve with the most complex set of connections Plays an important role in the PNS. It slows the heart and regulates the activity of internal organs. It also controls laryngeal muscles, which produce speech. Gaskin, Behavioral Neuropsychology, 1e. © SAGE 22 Publications, 2021.  Module 4.3 Test Yourself 4.3.1 Describe the somatic nervous system. What does it consist of, and what are its functions? 4.3.2 What are the divisions of the autonomic nervous system? What are its functions? Gaskin, Behavioral Neuroscience: essentials and beyond 1e. © SAGE Publications, 2021. 23  Applications Powered Exoskeletons in the Rehabilitation of Patients With Spinal Cord Injury Gaskin, Behavioral Neuroscience: essentials and 24 beyond 1e. © SAGE Publications, 2021.