Chapter 46: The Mammalian Nervous System: Structure and Higher Functions CHAPTER 46 The Mammalian Nervous System: Structure and Higher Functions

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions The Nervous System: Structure, Function, and Information Flow The Nervous System: Structure, Function, and Information Flow Functional Subsystems of the Nervous System Functional Subsystems of the Nervous System

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits Information Processing by Neuronal Circuits Understanding Higher Brain Functions in Cellular Terms Understanding Higher Brain Functions in Cellular Terms

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions The Nervous System: Structure, Function, and Information Flow Brain and spinal cord make up the central nervous system.Brain and spinal cord make up the central nervous system. Cranial and spinal nerves make up the peripheral nervous system.Cranial and spinal nerves make up the peripheral nervous system. A nerve is a bundle of many axons carrying information to and from the central nervous system.A nerve is a bundle of many axons carrying information to and from the central nervous system. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions The Nervous System: Structure, Function, and Information Flow The nervous system can be modeled conceptually in terms of direction of information flow and whether or not we are conscious of the information.The nervous system can be modeled conceptually in terms of direction of information flow and whether or not we are conscious of the information. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions The Nervous System: Structure, Function, and Information Flow The vertebrate nervous system develops from a hollow dorsal neural tube.The vertebrate nervous system develops from a hollow dorsal neural tube. The brain forms from three swellings at its anterior end, which become the:The brain forms from three swellings at its anterior end, which become the:  hindbrain,  midbrain, and  forebrain. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions The Nervous System: Structure, Function, and Information Flow The forebrain develops into the cerebral hemispheres and the underlying thalamus and hypothalamus.The forebrain develops into the cerebral hemispheres and the underlying thalamus and hypothalamus. The midbrain and hindbrain develop into the brain stem.The midbrain and hindbrain develop into the brain stem. More primitive and autonomic functions are localized in the brain stem, and conscious experience depends on the cerebrum.More primitive and autonomic functions are localized in the brain stem, and conscious experience depends on the cerebrum.12

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The nervous system is composed of many subsystems functioning simultaneously.The nervous system is composed of many subsystems functioning simultaneously. Some important ones are the spinal cord, reticular system, limbic system, and cerebrum.Some important ones are the spinal cord, reticular system, limbic system, and cerebrum.13

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The spinal cord communicates information between brain and body.The spinal cord communicates information between brain and body. It processes and integrates much information, and can issue some commands to the body without brain input.It processes and integrates much information, and can issue some commands to the body without brain input. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The reticular system of the brain stem is a complex network that directs incoming information to appropriate brain stem nucleiThe reticular system of the brain stem is a complex network that directs incoming information to appropriate brain stem nuclei They control autonomic functions, as well as transmitting the information to the forebrain resulting in conscious sensation.They control autonomic functions, as well as transmitting the information to the forebrain resulting in conscious sensation. The reticular system controls level of nervous system arousal.The reticular system controls level of nervous system arousal. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The limbic system is an evolutionarily primitive part of the forebrain involved in:The limbic system is an evolutionarily primitive part of the forebrain involved in:  emotions  physiological drives  instincts  memory. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The cerebral hemispheres are the dominant structures of the human brain.The cerebral hemispheres are the dominant structures of the human brain. Their surfaces consist of a layer of neurons called the cerebral cortex.Their surfaces consist of a layer of neurons called the cerebral cortex.20

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System Most of the cerebral cortex is involved in higher-order information processing, and these areas are generally called association cortex.Most of the cerebral cortex is involved in higher-order information processing, and these areas are generally called association cortex.21

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Functional Subsystems of the Nervous System The cerebral hemispheres can be divided into temporal, frontal, parietal, and occipital lobes.The cerebral hemispheres can be divided into temporal, frontal, parietal, and occipital lobes. Many motor functions are localized in the frontal lobeMany motor functions are localized in the frontal lobe Information from many receptors around the body projects to the parietal lobeInformation from many receptors around the body projects to the parietal lobe Visual information projects to the occipital lobeVisual information projects to the occipital lobe Auditory information projects to the temporal lobe.Auditory information projects to the temporal lobe. Review Figures 46.7, 46.8, 46.9,

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits The functions of the nervous system are beginning to be understood in terms of the properties of cells organized in neuronal circuits.The functions of the nervous system are beginning to be understood in terms of the properties of cells organized in neuronal circuits.28

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits The autonomic nervous system consists of efferent pathways that control the body’s organs and organ systems.The autonomic nervous system consists of efferent pathways that control the body’s organs and organ systems. Its sympathetic and parasympathetic divisions normally work in opposition.Its sympathetic and parasympathetic divisions normally work in opposition. They are characterized by their anatomy, neurotransmitters, and effects on target tissues.They are characterized by their anatomy, neurotransmitters, and effects on target tissues. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits Neuronal circuits in the occipital cortex integrate visual information.Neuronal circuits in the occipital cortex integrate visual information. Receptive field responses of retinal ganglion cells are communicated to the brain in optic nerves.Receptive field responses of retinal ganglion cells are communicated to the brain in optic nerves. This information is projected to the visual cortex so as to create receptive fields for cortical cells.This information is projected to the visual cortex so as to create receptive fields for cortical cells.32

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits A simple cell is stimulated by a bar of light with a specific orientation falling at a specific location on the retina.A simple cell is stimulated by a bar of light with a specific orientation falling at a specific location on the retina. A complex cell is maximally stimulated by such a stimulus moving across the retina.A complex cell is maximally stimulated by such a stimulus moving across the retina. The visual cortex seems to assemble a mental image of the visual world by analyzing edges of patterns of light.The visual cortex seems to assemble a mental image of the visual world by analyzing edges of patterns of light. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Information Processing by Neuronal Circuits Binocular vision results from circuits that communicate information from both eyes to binocular cells in the visual cortex.Binocular vision results from circuits that communicate information from both eyes to binocular cells in the visual cortex. These cells interpret distance by measuring the disparity between where the same stimulus falls on the two retinas.These cells interpret distance by measuring the disparity between where the same stimulus falls on the two retinas. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms Humans have a daily cycle of sleep and waking.Humans have a daily cycle of sleep and waking. Sleep can be divided into slow-wave and rapid-eye-movement sleep.Sleep can be divided into slow-wave and rapid-eye-movement sleep. Human non-REM sleep is divided into four stages of increasing depth.Human non-REM sleep is divided into four stages of increasing depth. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms Some learning and memory processes have been localized to specific brain areas.Some learning and memory processes have been localized to specific brain areas. Repeated activations of identified circuits in brain regions have revealed long-lasting changes in synaptic properties referred to as long-term potentiation and long-term depressionRepeated activations of identified circuits in brain regions have revealed long-lasting changes in synaptic properties referred to as long-term potentiation and long-term depression These may be involved in learning and memory.These may be involved in learning and memory. Review Figure

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Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms Complex memories can be elicited by stimulating small regions of association cortex.Complex memories can be elicited by stimulating small regions of association cortex. Damage to the hippocampus can destroy the ability to form long-term memories.Damage to the hippocampus can destroy the ability to form long-term memories.42

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms Language abilities are localized mostly in the left cerebral hemisphere, a phenomenon known as lateralization.Language abilities are localized mostly in the left cerebral hemisphere, a phenomenon known as lateralization.43

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms When the corpus callosum is cut, communication between left and right cerebral hemispheres is eliminated.When the corpus callosum is cut, communication between left and right cerebral hemispheres is eliminated.44

Chapter 46: The Mammalian Nervous System: Structure and Higher Functions Understanding Higher Brain Functions in Cellular Terms Different areas of the left hemisphere— including Broca’s area, Wernicke’s area, and the angular gyrus—are responsible for different aspects of language.Different areas of the left hemisphere— including Broca’s area, Wernicke’s area, and the angular gyrus—are responsible for different aspects of language. Review Figure

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