2.1: The Nervous System:The Central Nervous System

The Central Nervous System

• Central nervous system (CNS): The brain and spinal cord.

• Spinal cord: A column of nerves that transmits information between the brain and the peripheral nervous system.

• Spinal nerves: Major nerves that carry sensory and motor messages in and out of the spinal cord.

• Peripheral nervous system (PNS): The parts of the nervous system outside the brain and spinal cord.

• Neuron: A cell in the nervous system that transmits information.

• Nerve: A bundle of neuron axons.

• Cranial nerves: Major nerves that leave the brain without passing through the spinal cord.

  The Peripheral Nervous System

• Somatic nervous system (SNS): A network linking the spinal cord with the body and sense organs. Controls volunteer behavior

• Autonomic nervous system (ANS): The collection of axons that carry information to and from internal organs and glands. Self-governing, controls heart rate, perspiration, digestion, etc.

• Sympathetic nervous system (sympathetic branch): The division of the autonomic nervous system that coordinates arousal. Increases heart rate and respiration, decreases tears, salvation, digestion, and dilates pupils

• Parasympathetic nervous system (parasympathetic branch): The division of the autonomic nervous system that quiets the body and conserves energy. Stimulates tears and salvation, constricts respiration and blood vessels

  Neurons: The Building Blocks of the Nervous System

• Dendrites: Neuron fibers that receive incoming messages.

• Cell body (Soma): The part of the neuron or other cell that contains the nucleus of the cell.

• Axon: A fiber that carries information away from the cell body of a neuron.

• Axon terminals: Bulb-shaped structures at the ends of axons that form synapses with the dendrites and cell bodies of other neurons.

  How Neurons Work: Action Potentials

• Resting potential: The electrical charge of an inactive neuron.

• Threshold: In neurons, the point at which a nerve impulse is triggered.

• Action potential: A brief change in a neuron’s electrical charge.

• Myelin sheath: Insulating material that covers some axons.

• Ion channels: Tiny openings through the axon membrane.

• Negative after-potential: A drop in electrical charge below the resting potential.

  Synaptic Transmission

• Synapse: A microscopic space over which messages pass between two neurons.

• Synaptic transmission: The chemical process that carries information from one neuron to another.

• Neurotransmitter: A chemical that moves information from one nervous-system cell to another.

• Receptor site: An area on the surface of neurons and other cells that is sensitive to neurotransmitters or hormones.

  Neural Regulators

• Neuropeptides: Brain chemicals, such as enkephalins and endorphins, that regulate the activity of neurons.

  Neuroplasticity and Neurogenesis

• Neuroplasticity: The capacity of the brain to change in response to experience.

• Neurogenesis: The production of new brain cells.

2.2 Brain Research

CT Scans

• Computed tomographic (CT) scan: A computer-enhanced X-ray image of the brain or body.

  • Reveals brain structure, strokes, tumors, injuries, and brain disorders

MRI Scans

• Magnetic resonance imaging (MRI): An imaging technique that results in a three-dimensional image of the brain or body, based on its response to a magnetic field.

  • More detailed images than a CT provides

  • Can be used to explore brain pathways

Exploring Brain Function

• Localization of function: The research strategy of linking specific structures in the brain to specific psychological or behavioral functions.

  Surgical Techniques

• Electrical stimulation of the brain (ESB): Direct electrical stimulation and activation of brain tissue.

• Electrode: Any device (such as a wire, needle, or metal plate) used to stimulate or destroy nerve tissue electronically or to record its activity.

• Ablation: In biopsychology, the surgical removal of tissue from the surface of the brain.

• Deep lesioning: Removal of tissue within the brain by the use of an electrode.

  EEG

• Electroencephalograph (EEG): A device that records electrical activity in the brain.

  • Brain waves reveals tumors, epilepsy, and other diseases

  • Shows changes in brain activity during sleep, daydreaming, and hypnosis

PET Scans

• Position emission tomography (PET): A high-resolution imaging technique that captures brain activity by attaching radioactive particles to glucose molecules.

fMRI Scans

• Functional MRI (fMRI): An MRI technique that records activity levels in various areas of the brain.

2.3: The Cerebral Cortex

• Cerebral cortex: The thin, wrinkled outer covering of the brain in which high-level processes take place.

• Corticalization: An increase in the relative size of the cerebral cortex.

  The Cerebral Hemispheres

• Cerebral hemispheres: The left and right sides of the cerebral cortex; interconnected by the corpus callosum.

• Lateralization: Differences between the two sides of the body, especially differences in the abilities of the brain hemispheres.

• Split-brain operation: A surgical procedure that involves cutting the corpus callosum.

  Hemispheric Dominance

• Handedness: A preference for right or left hand in most activities.

• Dominant hemisphere: A term usually applied to the side of a person’s brain that produces language.

  Lobes of the Cerebral Cortex

• Lobes of the cerebral cortex: Areas on the left and right cortex bordered by major fissures or defined by their functions.

  The Frontal Lobes

• Frontal lobes: Areas of the cortex associated with movement, the sense of self, and higher mental functions.

• Prefrontal area (prefrontal cortex): The very front of the frontal loves; involved in the sense of self, executive functions, and planning.

• Executive functions: The higher-level mental processes that allow us to regulate and coordinate our own thought through processes.

• Association areas (association cortex): All areas of the cerebral cortex that are not primarily sensory or motor in function.

• Aphasias: A speech disturbance resulting from brain damage.

• Broca’s area: A language area related to grammar and pronunciation.

• Primary motor area (primary motor cortex): A brain area associated with the control of movement.

  Mirror Neurons

• Mirror neurons: Neurons that become active when a motor action carried out and when another organism is observed performing the same action.

• Motor neurons: A cell in the nervous system that transmits commands from the brain to the muscles.

• Autism spectrum disorder: A lifetime disorder whose primary features are impaired communication and social interaction.

  The Parietal Lobes

• Parietal lobes: Areas of the cortex in which body sensations register.

• Primary somatosensory area (primary somatosensory cortex): A receiving area for body sensations.

  The Temporal Lobes

• Temporal lobes: Areas of the cortex that include the sites where hearing registers.

• Primary auditory area (primary auditory cortex): The part of the temporal love that first receives input from the ears.

• Wernicke’s area: A temporal lobe brain area related to language comprehension.

  The Occipital Lobes

• Occipital lobes: Cortical areas at the back of the brain that play a role in visual processing.

• Primary visual area (primary visual cortex): The part of the occipital lobe that first receives input from the eyes.

• Visual agnosia: An inability to identify seen objects.

• Facial agnosia: An inability to perceive familiar faces.

  2.4: The Subcortex and Endocrine SystemThe Subcortex

• Subcortex: A term referring to all brain structures below the cerebral cortex.

  The Hindbrain

• Hindbrain: A primitive part of the brain that comprises the medulla, pons, and cerebellum.

• Medulla: The structure that connects the brain with the spinal cord and controls vital life functions.

• Pons: An area of the hindbrain that acts as a bridge between the medulla and other structures.

• Reticular formation (RF): A collection of cells and fibers in the medulla and pons involved in arousal and attention.

• Cerebellum: The structure in the hindbrain involved in controlling coordination and balance.

  The Midbrain

• Midbrain: A structure that connects the hindbrain with the forebrain.

  • Midbrain and medulla and pons make up the brain stem

  The Forebrain

• Forebrain: A brain structure, including the limbic system, thalamus, hypothalamus, and cortex that governs higher-order mental processes.

• Thalamus: A brain structure that relays sensory information to the cerebral cortex.

• Hypothalamus: A small area of the brain that regulates emotional behaviors and basic biological needs.

• Limbic system: A set of brain structures that play important roles in regulating emption and memory.

• Amygdala: A part of the limbic system associated with the rapid processing of emotions; especially fear.

• Hippocampus: Part of the limbic system associated with storing memories.

  The Endocrine System

• Endocrine system: A network of glands that release hormones into the bloodstream.

• Hormones: A chemical released by the endocrine glands.

  Pituitary Gland

• Pituitary gland: The master gland of the endocrine system that controls the action of all other glands.

• Growth hormone: A hormone, secreted by the pituitary gland, that promotes body growth.

• Oxytocin: A hormone, released by the pituitary gland, that plays a broad role in regulating pregnancy, parenthood, sexual activity, social bonding, trust, and even reducing stress reactions.

  Pineal Gland

• Pineal gland: A gland in the brain that helps regulate body rhythms and sleep cycles.

• Melatonin: A hormone released by the pineal gland in response to daily cycles of light and dark.

  Thyroid Gland

• Thyroid gland: An endocrine gland that helps regulate the rate of metabolism.

  Adrenal Glands

• Adrenal glands: Endocrine glands that arouse the body, regulate salt balance, adjust the body to stress, and affect sexual functioning.

• Epinephrine: An adrenal hormone that tends to arouse the body; epinephrine is associated with fear. (Also known as adrenaline.)

• Norepinephrine: Both a brain neurotransmitter and an adrenal hormone that tends to arouse the body; norepinephrine is associated with anger. (Also known as noradrenaline.)

  2.5: Psychology and Your Skill Set: Self Regulation

• Self-regulation: The ability to consciously exert self-control.

Chapter in Review:

2.1 The Nervous System

Outline the major divisions of the nervous system

The nervous system can be divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is made up of the brain, which carries out most of the “computing” in the nervous system, and the spinal cord, which connects the brain the to the PNS. The PNS included the somatic nervous system (SNS), which carries sensory information to the brain and motor commands to the body, and the autonomic nervous system (ANS), which controls vegetative and automatic bodily processes. The ANS has a sympathetic branch and a parasympathetic.

Identify the important parts of a neuron

Key parts of a neuron include the dendrites (which receive incoming messages), the cell body (which receives information from dendrites), the axon (which carries information away from the cell body), and the axon terminals (where information is passed along to adjacent neurons).

Describe how neurons operate and communicate with each other

The dendrites and soma of a neuron combine neural input and send it down the axon as an action potential. The action potential travels to the axon terminals. Neural function, including fluctuations of the neuron’s resting potential and the firing of the action potential, is basically electrical in nature.

Communication between neurons is chemical. When an action potential reaches the end of the axon terminals, neurotransmitters are released into the synapse and attach to receptor sites on the adjacent neurons, exciting or inhibiting them. Chemicals called neuropeptides can also regulate synaptic activity in the brain.

Distinguish between neuroplasticity and neurogenesis

Neuroplasticity refers to the brain’s ability to change in response to experiences. While neurons and nerves in the PNS often can regenerate, the term neurogenesis refers to the production of new neurons in the brain.

2.2 Brain Research

Identify three methods that scientists use to understand the structures of the brain

Brain structure is investigated through dissection, as well as less-intrusive CT scans and MRI scans.

Identify four methods that scientists use to understand the function of brain structures

Brain function is investigated through surgical procedures (electrical stimulation, ablation, deep lesioning), as well as less-intrusive EEG recording, PET scans, and fMRI scans.

2.3 The Cerebral Cortex

Explain how the left and right hemispheres of the cerebral cortex differ as a result of lateralization

The cerebral cortex is lateralized, with left and right hemispheres specializing in different abilities. Much of what we have learned about lateralization come from spilt-brain patients whose corpus callosum has been surgically cut. Such an operation allows information to be sent to only one hemisphere processes the information in the absence of any input from the other hemisphere.

Psychologists have learned that the left hemisphere is good at analysis, and it processes small details sequentially. It contains speech or language centers in most time and rhythm, and ordering complex movements. The right hemisphere detects overall patterns; it processes information simultaneously and holistically. It is largely nonverbal and excels at spatial and perceptual skills, visualization, and recognition of patterns, faces and melodies. It is important to note, however, that while the hemispheres appear to specialize in their functions, there is no merit to the idea that people are “left-brained” or “right-brained.”

Name the four lobes of the cerebral cortex and describe their function

1. The frontal lobes contain the primary motor area (which includes many mirror neurons) and many association areas that combine and process information. The prefrontal cortex is related to abstract through one’s sense of self.

2. The parietal lobes contain the primary sensory area, which processes bodily sensations.

3. The temporal loves contain the primary auditory area and are responsible for hearing and language.

4. The occipital lobes contain the primary visual area, which first receives input from the eyes.

2.4 The Subcortex and Endocrine System

Name the three major regions of the subcortex, and the parts that make up each one

The three regions are the hindbrain, midbrain, and forebrain. The hindbrain is made up of the medulla (which contains centers essential for reflex control of heart rate, breathing and other vegetative functions), the reticular formation (which directs sensory and motor messages and acts as an activating system for the cerebral cortex), and the cerebellum (which maintains coordination, posture and muscle tone). The pons links the medulla with other brain areas.

The midbrain connects the hindbrain to the forebrain. The midbrain and two hindbrain structures (pons and medulla) make up the brainstem, which is the thickening of the spinal cord where it joins the brain.

The forebrain consists of the thalamus (which carries sensory information to the cortex), the hypothalamus (which exerts control over eating, drinking, sleep cycles, body temperature, and other basic motives and behaviors), and the limbic system (which is related to emotion, reward and punishment, and contains the hippocampus, which is important for forming memories.)

Explain how the endocrine system works, and describe the action of four endocrine glands

Endocrine glands serve as a chemical communication system within the body. Hormones from the endocrine glands enter the bloodstream, affecting behavior, moods, and personality. Many of the endocrine glands are influenced by the pituitary gland (the master gland), which is in turn influenced by the hypothalamus. Thus, the brain controls the body through both the fast nervous system and the slower endocrine system. Four important endocrine glands are:

1. The pituitary gland, which influences many other glands, including the thyroid and adrenal glands. It is also responsible for growth (through the release of growth hormone) and social bonding (through the release of oxytocin).

2. The pineal gland, which regulated the body’s internal clock (through the release of melatonin).

3. The thyroid gland, which regulates metabolism.

4. The adrenal glands, which regulate the body’s response to stress (through the release of epinephrine and norepinephrine) and sexual development.

2.5 Psychology and Your Skill Set: Self Regulation

Define self-regulation, and explain how it can help you in your personal and professional life

Self-regulation refers to our ability to control our thoughts, emotions, and behavior. It is associated with the frontal lobes of the brain, which manage our executive functions. Executive functions allow us to set goals, make plans to achieve those goals, control attention and emotions as we work towards our goal so that we know if we need to change our strategy.

Because of its close link to goals, self-regulation in childhood predicts many things connected to personal and professional success, including health, antisocial and criminal behavior, and financial security.

Create a plan to improve your self-regulation skills in an area that is important to you

Self-regulation skills can be improved by changing what we pay attention to, how we think about situations we’re in, or the environments we find ourselves in.