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The Brain & the Nervous System
This document provides an overview of basic neuroscience topics including the nervous system, neurons, neurotransmission, brain structures and functions, and various brain imaging techniques. It discusses the key components and functions of neurons, describes the central and peripheral nervous systems, examines different neurotransmitters and their roles, explores the major divisions and regions of the brain including the cortex, limbic system and basal ganglia, and summarizes several imaging methods used to study the living brain.
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The Brain & the Nervous System
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- 5. BASIC NEURO- SCIENCE THE NERVOUS SYSTEM NEURONSAND NEUROTRANSMITTERS ENDOCRINE DISORDERS COGNITIVE DISORDERS SPECAIL TOPICS PSCYHO- PHARMA- COLOGY ANTIPSYCHOTICS ANTIDEPRESSANTS BENZODIAZEPINES MOOD STABILIZERS STIMULANTS
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- 9. Neurons releaseneurotransmitters to communicate • Receive information by capturing neurotransmitters released in the synaptic cleft 1) Dendrites: • Integrates information from the dendrites. Contains the nucleus and controls hereditary characteristics 2) The cell body or soma: • tube-like structure that transmits information 3) Axon:
- 11. Fatty substance acts as aninsulator Speeds up conduction Glial cells Hold neurons together Provide neuron with nutrients Remove cellular debris
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- 14. Negative resting state Potassium and Sodium ions switch places which releases neurotransmitters at the synaptic cleft All or none principle: If sufficiently stimulated, will fire to its full extent
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- 16. Dived intotwo categories: Classical neurotransmitters Peptide neurotransmitters Substances that impact NT: Agonist: enhances effect of NT Antagonist: inhibits effect of NT Action Potential categories: Excitatory: Acetylcholine, norepinephrine increase likelihood of action potential Inhibitory: GABA, endorphin decrease likelihood of action potential
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- 19. All behaviorresults from activity in the cells of the nervous system Two divisions: Central nervous system Peripheral nervous system
- 20. Spinal cordand brain Sensory neurons carry info to CNS Motor neurons carry info away from CNS to muscles and glands
- 22. The SomaticNervous System Sends and receives sensory messages that control voluntary motor movement of the skeletal muscles Autonomic Nervous System Smooth muscles Digestion Heart rate Breathing
- 23. Sympathetic Arousaland expenditure of energy External threat Fight or flight Parasympathetic Conservation of energy Rest/relaxation Meditation, hypnosis, biofeedback Can work together, not just in opposition!
- 24. Control center formost voluntary and involuntary behavior
- 25. Control centerfor all voluntary and most involuntary behavior Brain Areas: Cerebrum Cerebellum Brain Stem Brain Divisions: Forebrain Midbrain Hindbrain
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- 27. Second largeststructure Coordinates habitual muscle movements Tracking target with eyes Playing saxophone Excitatory inputs for maintaining smooth movement and coordinating motor activity Ataxia: lack of coordination
- 28. Pons: • Sleep • Respiration •Movement • Cardiovascular activity • Facial expressions Medulla • Blood pressure • Heart rate • Breathing Damage to medulla & Pons • Failure can lead to death and loss of bodily functions
- 29. Smallest region ofthe brain Relay station for auditory and visual information. The Functions: • Visual and auditory systems • eye movement.
- 30. Awareness, attentionand sleep Damage: disrupt sleep, permanentn coma-like sleep Spinal cord Hypothalamus Forebrain Reticular activating system projects to thalamus and wakes you up
- 31. Tucked intothe center of the brain
- 32. Our primitive brain: systemof various structures in forebrain • Emotions • Basic drives • Learning • Influence autonomic nervous system and endocrine system
- 33. Relays information from thesensory receptors to proper areas of the brain Wernicke-Korsakoff Syndrome • Thiamine deficiency Korsakoff’s Syndrome • Severe amnesia & Other symptoms
- 34. Fever Feeding Fighting FallingAsleep Fucking Hypothalamus regulates Homeostasis
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- 36. Basil Ganglia Problems: Huntington’s: • Degenerationof caudate nucleus & putamen • Unwanted thrusting movements Parkinson’s: • Loss of dopaminergic neurons in Substantia Nigra • Tremor, rigidity, bradykinesia
- 37. Gives emotionalsignificance to sensory input Amygdala/Aggression Kluver-Bucy syndrome if destroyed
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- 39. Memory • Consolidation ofconscious memories • If you saw a Hippo on Campus you would remember her.
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- 41. Complex thought,perception and action
- 42. Two hemispheres connected bythe corpus callosum (thick band of fibers) Four lobes separated by grooves (sulci)
- 43. Left controlsright, right controls left side of body Important distinctions of respective functions Right is for Intuition, Artistic, Emotions Left is for Language and Logic
- 44. Bundle of nervefibers that bridge left and right hemispheres Split-brain patients
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- 47. Frontal, Parietal,Temporal, Occipital
- 48. Top front ofbrain • Prefrontal cortex • Premotor area • Motor area Broca’s Area • Expressive Speech
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- 50. Connected to limbic system Functionsof Temporal Lobes • Primary auditory cortex • Emotional behavior • Memory • Interprets Speech (Wernicke’s Area)
- 51. Primary visual cortex,sight, reading and visual images
- 52. EEG: Detects brain waves;sleep research CAT Scan: View brain structure, 3-D picture, sophisticated X-Ray PET scan: Measures chemicals (aka) glucose; functional capacity of brain MRI: radio waves to see structures fMRI: Cobmines MRI and PET scan; details of structure and activity
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Editor's Notes
- #3 How experts think, the power of framing, the miracle of attention, the weird world of cognitive biases and more… Fifty years ago there was a revolution in psychology which changed the way we think about the mind. The ‘cognitive revolution’ inspired psychologists to start thinking of the mind as a kind of organic computer, rather than as an impenetrable black box which would never be understood. This metaphor has motivated psychologists to investigate the software central to our everyday functioning, opening the way to insights into how we think, reason, learn, remember and produce language.
- #4 Phineas P. Gage (1823 – May 21, 1860) was an American railroad construction foreman remembered for his improbable[B1]:19 survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior over the remaining twelve years of his life—effects so profound (for a time at least) that friends saw him as "no longer Gage". Long known as "the American Crowbar Case"—once termed "the case which more than all others is calculated to excite our wonder, impair the value of prognosis, and even to subvert our physiological doctrines"[2]—Phineas Gage influenced nineteenth-century discussion about the mind and brain, particularly debate on cerebral localization,[M]:ch7-9[B] and was perhaps the first case to suggest that damage to specific parts of the brain might induce specific personality changes.[M]:1[M3]:C Gage is a fixture in the curricula of neurology, psychology, and related disciplines (see Neuroscience),[3][M7]:149 "a living part of the medical folklore"[R]:637 frequently mentioned in books and scientific papers;[M]:ch14 he even has a minor place in popular culture.[4] Despite this celebrity, the body of established fact about Gage and what he was like (before or after his injury) is small,[c] which has allowed "the fitting of almost any theory [desired] to the small number of facts we have"[M]:290—Gage acting as a "Rorschach inkblot"[5] in which proponents of various conflicting theories of the brain were able to find support for their views. Historically, published accounts (including scientific ones) have almost always severely distorted and exaggerated Gage's behavioral changes, frequently contradicting the known facts. A report of Gage's physical and mental condition shortly before his death implies that his most serious mental changes were temporary, so that in later life, he was far more functional, and socially far better adapted, than in the years immediately following his accident. A social recovery hypothesis suggests that his employment as a stagecoach driver in Chile provided daily structure allowing him to regain lost social and personal skills.
- #5 https://www.youtube.com/watch?v=MvpIRN9D4D4 Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development.[1] It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube fails to close, usually between the 23rd and 26th day following conception.[2] Strictly speaking, the Greek term translates as "no in-head" (that is, totally lacking the inside part of the head, i.e., the brain), but it is accepted that children born with this disorder usually only lack a telencephalon,[3] the largest part of the brain consisting mainly of the cerebral hemispheres, including the neocortex, which is responsible for cognition. The remaining structure is usually covered only by a thin layer of membrane— skin, bone, meninges, etc. are all lacking.[4] With very few exceptions,[5][6] infants with this disorder do not survive longer than a few hours or possibly days after their birth.
- #10 A neuron (/ˈnjʊərɒn/ nyewr-on or /ˈnʊərɒn/ newr-on; also known as a neurone or nerve cell) is an electrically excitable cell that processes and transmits information through electrical and chemical signals. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to form neural networks. Neurons are the core components of the brain and spinal cord of the central nervous system (CNS), and of the ganglia of the peripheral nervous system (PNS). Specialized types of neurons include: sensory neurons which respond to touch, sound, light and all other stimuli affecting the cells of the sensory organs that then send signals to the spinal cord and brain, motor neurons that receive signals from the brain and spinal cord to cause muscle contractions and affect glandular outputs, and interneurons which connect neurons to other neurons within the same region of the brain, or spinal cord in neural networks. A typical neuron consists of a cell body (soma), dendrites, and an axon. The term neurite is used to describe either a dendrite or an axon, particularly in its undifferentiated stage. Dendrites are thin structures that arise from the cell body, often extending for hundreds of micrometres and branching multiple times, giving rise to a complex "dendritic tree". An axon is a special cellular extension that arises from the cell body at a site called the axon hillock and travels for a distance, as far as 1 meter in humans or even more in other species. The cell body of a neuron frequently gives rise to multiple dendrites, but never to more than one axon, although the axon may branch hundreds of times before it terminates. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: neurons that lack dendrites, neurons that have no axon, synapses that connect an axon to another axon or a dendrite to another dendrite, etc. All neurons are electrically excitable, maintaining voltage gradients across their membranes by means of metabolically driven ion pumps, which combine with ion channels embedded in the membrane to generate intracellular-versus-extracellular concentration differences of ions such as sodium, potassium, chloride, and calcium. Changes in the cross-membrane voltage can alter the function of voltage-dependent ion channels. If the voltage changes by a large enough amount, an all-or-none electrochemical pulse called an action potential is generated, which travels rapidly along the cell's axon, and activates synaptic connections with other cells when it arrives. Neurons do not undergo cell division. In most cases, neurons are generated by special types of stem cells. A type of glial cell, called astrocytes (named for being somewhat star-shaped), have also been observed to turn into neurons by virtue of the stem cell characteristic pluripotency. In humans, neurogenesis largely ceases during adulthood; but in two brain areas, the hippocampus and olfactory bulb, there is strong evidence for generation of substantial numbers of new neurons.[1][2]
- #11 Specialized types of neurons include: sensory neurons which respond to touch, sound, light and all other stimuli affecting the cells of the sensory organs that then send signals to the spinal cord and brain, motor neurons that receive signals from the brain and spinal cord to cause muscle contractions and affect glandular outputs, and interneurons which connect neurons to other neurons within the same region of the brain, or spinal cord in neural networks.
- #12 The insulating envelope of myelin that surrounds the core of a nerve fiber or axon and that facilitates the transmission of nerve impulses, formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells. Also called medullary sheath. A fatty, axon-enwrapping sheath that serves to speed up neural conduction, formed by concentric layers of Schwann's cell (peripheral) or oligodendrocyte (CNS) membranes; loss or damage leads to severe loss of neural function, as in multiple sclerosis. Definition from: CRISP Thesaurus via Unified Medical Language SystemThis link leads to a site outside Genetics Home Reference. at the National Library of Medicine The lipid-rich sheath surrounding axons in both the central and peripheral nervous systems. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (Schwann cells in the peripheral and oligodendroglia in the central nervous system). Deterioration of the sheath in demyelinating diseases is a serious clinical problem.
- #13 We are going to talk about the action potential and such, neurons are about communication. Here’s how.
- #14 Neuron functioning
- #15 In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. The resting potential tells about what happens when a neuron is at rest. An action potential occurs when a neuron sends information down an axon, away from the cell body. Neuroscientists use other words, such as a "spike" or an "impulse" for the action potential. The action potential is an explosion of electrical activity that is created by a depolarizing current. This means that some event (a stimulus) causes the resting potential to move toward 0 mV. When the depolarization reaches about -55 mV a neuron will fire an action potential. This is the threshold. If the neuron does not reach this critical threshold level, then no action potential will fire. Also, when the threshold level is reached, an action potential of a fixed sized will always fire...for any given neuron, the size of the action potential is always the same. There are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired - this is the "ALL OR NONE" principle. When a neuron is not sending a signal, it is "at rest." When a neuron is at rest, the inside of the neuron is negative relative to the outside. Although the concentrations of the different ions attempt to balance out on both sides of the membrane, they cannot because the cell membrane allows only some ions to pass through channels (ion channels). At rest, potassium ions (K+) can cross through the membrane easily. Also at rest, chloride ions (Cl-)and sodium ions (Na+) have a more difficult time crossing. The negatively charged protein molecules (A-) inside the neuron cannot cross the membrane. In addition to these selective ion channels, there is a pump that uses energy to move three sodium ions out of the neuron for every two potassium ions it puts in. Finally, when all these forces balance out, and the difference in the voltage between the inside and outside of the neuron is measured, you have the resting potential. The resting membrane potential of a neuron is about -70 mV (mV=millivolt) - this means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.
- #18 Make love not war chimpanzee. Could it be that Kanzi’s neural wiring contributes to his attentiveness and ability to use symbols and understand language? Is his ability to empathize with others what makes him a good listener and communicator? It seems to be one of many factors, but certainly not the only prerequisite. As the structure/function debate continues, I still find it fascinating to see our notions of the brain as an impenetrable “black box” turn grayer with time.
- #34 Sensory signals come from up the spinal cord and are sent to appropriate areas in rest of forebrain The Quick Facts Location: Part of the forebrain, below the corpus callosum Function: Responsible for relaying information from the sensory receptors to proper areas of the brain where it can be processed The thalamus is similar to a doctor that diagnoses, or identifies, a patient's disease or sickness. It diagnoses different sensory information that is being transmitted to the brain including auditory (relating to hearing or sound), visual, tactile (relating to touch), and gustatory (relating to taste) signals. After that, it directs the sensory information to the different parts and lobes of the cortex. If this part of the brain is damaged, all sensory information would not be processed and sensory confusion would result. Thiamine deficiency Atrophy of neurons Result of chronic alcoholism Begins with Wernicke’s encephalopathy: mental confusion, abnormal eye movements, ataxia Severe anterograde, retrograde amnesia Confabulation
- #37 Regulation and coordination of movement The Basal Ganglia are inhibitory, and put brakes on movement
- #38 Removal or Destruction of Amygdala Placidity Apathy Hyperphagia Hypersexuality Agnosias
- #39 Removal or Destruction of Amygdala Placidity Apathy Hyperphagia Hypersexuality Agnosias
- #44 Brain Lateralization Contralateral representation Left controls right, right controls left Except olfactory Brain lateralization 95-99% of right handed people are left brained 50-60% of left handed are left brained Hempisphereic specialization Left dominance: Reading Writing Speaking Spelling Naming Motor Control Right Dominance: Dominance: Perceptual Artistic Musical Intuitive Body Image Comprehension of visual, facial, verbal emotion Problems: Hemi-neglect, prosopagnosia, visual-perceptual disturbances, musical agnosia Affective: Indifference, euphoria, hysteria, impulsivity, abnormal sexual behavior, etc…
- #49 3 main areas Prefrontal cortex Personality Planning Inhibition Premotor area Planning movement Motor area Instigate voluntary movement Damage: Loss movement Personality, attention, thinking problems Inability to express language (Broca’s aphasia) Primary motor cortex Precise control Supplementary motor area Planning and controlling movement Premotor cortex Primary motor control Broca’s: left frontal lobe
- #50 Right Parietal Lesions -> Contralateral neglect Left Parietal Lesions -> Ideational apraxia, ideomotor apraxia, Gerstmann’s syndrome Apraxia: Muscles work, but you can’t coordinate movement Anosognosia: Can’t recognize shit Sensory cortex: top receives sensations from bottom of body and progresses down
- #51 Wernicke’s Comprehend Speech Left Hempisphere Lesions: Auditory agnosia Halluciantions Disturbances in auditorysensation and perception Mediates: Encoding, retrieval and storage of long-term declarative memories Electrical stimulation can elicit vivid memories that were forgotten Location: Bottom middle part of cortex, right behind the temples Function: Responsible for processing auditory information from the ears (hearing) The Temporal Lobe mainly revolves around hearing and selective listening. It receives sensory information such as sounds and speech from the ears. It is also key to being able to comprehend, or understand meaningful speech. In fact, we would not be able to understand someone talking to us, if it wasn't for the temporal lobe. This lobe is special because it makes sense of the all the different sounds and pitches (different types of sound) being transmitted from the sensory receptors of the ears.
- #52 Primary visual cortex, sight, reading and visual images Visual cortex Visual Agnosia Hallucinations, cortical blindness Prosopagnosia Inability to recognize familiar faces Simultanagnosia Can’t see more than one thing or aspect of object at a time
- #54 Professor Yang Dan at UC Berkeley demonstrates the technology that captures images of what a cat sees. This is one approach to the technical challenge to remotely acquire the vision of an animal. http://news.bbc.co.uk/1/hi/sci/tech/4... (2001) Dr José Manuel Rodriguez Delgado states in an interview on electromagnetic fields and their effect on people. "I could later do with electro-magnetic radiation what I did with the stimoceiver. It's much better because there's no need for surgery," http://www.cabinetmagazine.org/issues...