Neuro Science Podcast Essay

 

 

Here are the steps to follow:

1) Find a high quality podcast episode on a neuroscience topic that interests you and that can be connected to the content of this course. The episode should be at least 45 minutes in duration. Try to find podcasts published within the last 5 years. At the end of the assignment instructions, you will find some examples of high quality podcasts with episodes on neuroscience topics.

2) Your neuroscience episode should not already be covered by a classmate. It should be unique to you. Once you find an episode of interest to you, check to see that it is not already being used by someone else by checking the discussion in BlackBoard. If no one else is using the article, then, to avoid duplication, start a thread in BlackBoard and complete step “3)”, just below. You’ll be able to return to your thread and continuing writing at a later time.

3) At the top of the assignment, before you start writing, provide a reference to the podcast episode: 1) the name of the podcast, 2) the podcast title, 2) the interviewer, 3) the interviewee(s), 4) the episode number, 5) date, and 6) a link to the story on the podcast episode.

4) When you are ready to begin writing, first, in your own words, provide a clear summary of main points, issues, and/or conclusions discussed during the podcast.

5) Then, second, clearly articulate what is it about the episode research topic that interests you? For example, the topic may be interesting in and of itself; the area of research may have application to other aspects of our lives; the topic may have relevance to your life in particular. Provide a clear description of why it is that the research topic is of interest to you.

6) Your assignment should include two sections, one for the first part and one for the second part. More importantly, the assignment should be well-written, thorough, and complete. Please make it easy for me to give you all of the assignment points!!!

Here are some examples of podcasts with high quality neuroscience episodes:

“Brain Science with Ginger Campbell, MD: A Neuroscience Podcast for Everyone

“CortexCast – A Neuroscience Podcast”

“Navigating Neuropsychology”

“Huberman Lab”

“The Language Neuroscience Podcast”

“Radio Lab”

“Here We Are”

Here are the topics that can be cover in the podcast/answer:

Chapter 1: Introduction to Physiology of Behavior

• Cognitive and Behavioral Neuroscience, also called Physiological Psychology describes the physical mechanisms of the body that mediate movement and mental activity
• 2 views of the relationship between the mind and the body:
  • Dualism: mind and body are separate but interacting
  • Monism: mind is a property of the physical nervous system (and body): Mind and body not separate
• Consciousness refers to self-awareness
  • It is the ability to communicate thoughts, perceptions, feelings, and memories
  • It can vary across the day/night cycle
  • Special states of consciousness: Sleep and dreaming
  • Drugs can alter it, i.e., alcohol or LSD
  • Variations in consciousness are linked to specific physiological, bodily, and neural mechanisms and processes
  • Damage to the visual system will produce blindness in the visual field
    • Blindsight: when blind patients are able to reach for objects placed in their blind visual field
      • implies that consciousness of a stimulus not needed in order to act on that stimulus
      • much visual info is processed without awareness, even in those with intact brains, e.g., saccadic suppression
• Size-contrast illusions deceive the eye, but not the hand (Aglioti, DeSouza, Goodale, 1995)
• Goal of science:
  • Explain the phenomena under study
    • Generalization: the deduction of general laws, using results from experiments
    • Reduction: the use of simple phenomena to explain more complicated phenomena
• Descartes’ View of Behavior (1596-1650) is the world is mechanistic:
  • Some human behavior and all non-human animal behavior are reflexive mechanisms brought about by stimuli in the environment
    • Proposed that the mind interacts with the physical body through the pineal body
    • Viewed hydraulic pressure within nerves as the basis for movement
      • Notion of contralateral
    • Identified primary motor cortex
      • This is a region of the cortex that activates discrete muscles on the opposite side of the body
      • Other brain regions control movements via connections with primary motor cortex
• Falsification of Water and Air “Balloonist Theories”
• Luigi Galvani (1737-1798): Showed that stimulation of isolated frog nerves will evoke muscle contraction
• Fluorens
  • Used ablation (removal of brain areas) in animals to assess the role of the brain in the control of behavior
  • Reported discrete brain areas that controlled heart rate and breathing, purposeful movements, and visual and auditory reflexes
• Broca’s Area
  • Patient “Tan” showed major deficit in speech (aphasia) following a stroke
  • Broca’s autopsy of Tan’s brain in 1861 noted damage in the left hemisphere
  • Broca’s Area is a lexicon; it is specialized for speech production and storing vocabulary
• Electrical Stimulation of the Brain: Fritsch and Hitzig
• Cortical Reorganization in Motor Cortex After Graft of Both Hands (Giraux and colleagues)
  • 1996: patient C.D. has hands amputated; 2000: bilateral hand transplants; fMRI activity measured 6 months before graft and 2, 4, and 6 months after graft
• Human Brain-Computer Interface and Monkey Brain-Robotic Arm Interface (Schwartz et al,)
• Charles Darwin
  • Functionalism: the belief that the characteristics of an organism serve some useful function
    • Hands allow for grasping
    • Skin color can allow an organism to blend into the background, e.g., To avoid predators
    • Color vision allow for detection of ripe/rotten food
  • Natural Selection: characteristics that allow an organism to reproduce more successfully are passed on to offspring. Consequence: these characteristics will become more prevalent in a species
  • Evolution: the gradual change in structure and physiology as a result of natural selection
• Human Evolution
  • Hominids are humanlike apes that first appeared in Africa
    • Humans evolved from the first hominids
      • Four surviving species of hominids: Humans, Chimpanzees, Gorillas, Orangutans
        • Humans and chimpanzees share 98.8% of DNA
  • Humans evolved a number of characteristics that enabled them to fit into their environment and to successfully compete, for example:
    • Color vision, Upright posture/bipedalism, Language abilities
      • They required a larger brain; Human brains are large relative to body weight
• Brain-Body Mass Relation
• Ethics of Animal Research
• Cognitive and Behavioral Neuroscientists (Physiological Psychologists) study animals to learn about the relation between physiology and behavior
  • Animal research must be humane and worthwhile; animal studies are justified on the basis of:
    • Minimized pain and discomfort and the value of the information gained from the research, for example: Progress in developing vaccines and progress in preventing cell death immediately after a stroke
    • The importance of science for understanding ourselves and animals
• Careers in Neuroscience
  • Can study the physiology of behavioral phenomena in animals
    • Cognitive and Behavioral Neuroscience is also known as Psychobiology, Biopsychology, Physiological psychology
  • Most physiological psychologists have earned a doctoral degree in psychology or in neuroscience
  • Neurologists are physicians who diagnose and treat nervous system diseases
• Neurons can be classified according to
  • Locations in Nervous System
    • CNS: parts encased in the skull and spinal bones vs. PNS: spinal and cranial nerves outside the CNS
  • Function
    • Sensory neurons carry messages toward brain; Motor neurons carry messages to muscles; Interneurons exist in between and neither directly pick up sensory information or send motor commands muscles
  • Numbers of axon processes: Multipolar: one axon, many dendritic branches; Unipolar: many dendrites one axon with cell body to the side; Bipolar: one dendriteaxoncell bodyaxon
  • Effects of neurotransmitter: excitatory vs inhibitory
• (Multipolar) Neuron Structure: Know parts of the neuron and be able to identify them
• Neuron Figures: Multipolar vs. Bipolar vs. Unipolar Neurons
• Neuron Structures (Figure 2.5 Carlson)—Know basic functions
  • Membrane: Defines the cell boundary; Composed of a double layer of lipids
  • Cytoplasm: The viscous, semiliquid substance in the cell
  • Nucleus: Contains genetic information; Important for protein synthesis
  • Mitochondria: Extracts energy from nutrients and Provides ATP
  • Lysosome: Small sacs; Contain enzymes for substance break down
  • Microtubules: Long strands of protein filaments involved in substance transport
  • Myelin sheath: Insulation from the glial cells
  • Dendrites: Branch-like structures of the neuron
  • Dendritic spines: A location for synapse formation
• A Withdrawal Reflex (Hot Iron) and the Role of Inhibition (Casserole)
• CNS Support Cells
  • Neuroglia: the “glue”: Provide physical support; Control nutrient flow; Involved in phagocytosis
  • Astrocytes: Provide physical support; Remove debris; Transports nutrients to neurons
  • Microglia: Involved in phagocytosis; Involved in brain immune function
  • Oligodendroglia: Provide physical support; Form the myelin sheath around axons in the brain
  • Schwann cells: form myelin for PNS axons
• The Blood Brain Barrier, Area Postrema, and Conditioned Taste Aversion
• Microtubules—know how microtubules work
• Nerve cells are specialized for communication
  • Neurons conduct electrochemical signals
    • Dendrites receive chemical messages from adjoining cells
    • Chemical messengers activate receptors on the dendritic membrane
    • Receptor activation opens ion channels which can alter membrane potential
    • Action potential can result and is propagated down the membrane
    • Action potential causes release of transmitter from axon terminals
• Measuring Membrane Potential of a Neuron in a Squid:
  • Giant axon from a squid is placed in seawater in a recording chamber
  • Glass microelectrode is inserted into axon
    • Voltage measures -70 mV inside with respect to outside
• Resting Membrane Potential vs Membrane Potential
• Action Potential as Seen on an Oscilloscope Screen—Know characteristics of action potential from figure
• Forces of Diffusion and Electrostatic Pressure Maintain RMP
• Relative Ion Concentrations Across the Axon Membrane Maintain RMP
• Ion Channels
• The Movements of Ions During the Action Potential
• Action potential: a stereotyped change in membrane potential
  • If resting membrane potential moves past threshold, membrane potential quickly moves to +40 mV and then returns to rest
  • Ionic basis of the action potential:
    • Sodium (Na+) in: upswing of spike: Diffusion, Electrostatic pressure
    • Potassium (K+) out: downswing of spike
• Properties of the action potential:
  • “All or None” event: Resting membrane potential either passes threshold or doesn’t
  • Has a fixed amplitude: Action potentials don’t change in height to signal information
  • Has a conduction velocity measured in meters/second
  • Has a refractory period that limits firing rate: Stimulation will not produce an action potential
  • Is propagated down the axon membrane: Notion of successive patches of membrane
• Conduction of the Action Potential: Understand Wavelike Properties of Action Potential
• Decremental Conduction
  • Local disturbances of membrane potential are carried along the membrane
    • Local potentials degrade with time and distance
    • Local potentials can summate to produce an action potential
• Saltatory Conduction
  • Action potentials are propagated down the axon
    • Action potential depolarizes each successive patch of membrane in nonmyelinated axons; this slows conduction speed
    • In myelinated axons, the action potential “jumps” from node to node, depolarizing the membrane at each node
      • Conduction velocity is proportional to axon diameter: Increases in diameter = increases in speed
      • Myelination and salutatory conduction allow smaller diameter axons to conduct signals quickly
      • More axons can be placed in a given volume of brain
• Communication Between Neurons
• Synapse: the gap between pre- and post-synaptic membranes (~20-30 nMeters)
  • Presynaptic membrane is typically an axon terminal button
  • Postsynaptic membrane can be:
    • A dendrite (axodendritic synapse)
    • A cell body (axosomatic synapse)
    • Another axon (axoaxonic synapse)
• Types of Synapses
• Overview of the Synapse
• Neurotransmitter Release
  • Vesicles lie “docked” near the presynaptic membrane
  • The arrival of an action potential at the axon terminal opens voltage-dependent Ca++ channels
    • Ca++ ions flow into the terminal button
    • Ca++ ions change the structure of the of the proteins that bind the vesicles to the presynaptic membrane
    • A fusion pore is opened, which results in the merging of the vesicular and presynaptic membranes
  • The vesicles release their contents into the synapse
    • The released transmitter then diffuses across the cleft to interact with postsynaptic membrane receptors
• Postsynaptic Receptors
  • Molecules of neurotransmitter bind to receptors located on the postsynaptic membrane
    • Receptor activation opens postsynaptic ion channels
    • Ions flow through the membrane, producing either depolarization or hyperpolarization
    • The resulting postsynaptic potential (PSP) depends on which ion channels is opened
  • Postsynaptic receptors alter ion channels
    • Directly: Called ionotropic receptors
    • Indirectly using second messenger systems that require energy: Called metabotropic receptors
• Ionotropic Receptors
• Postsynaptic Potentials (PSP)
  • Excitatory Postsynaptic Potentials(EPSP): Opening of Na+ ion channels results in an EPSP through Na+ influx
  • Inhibitory Postsynaptic Potentials (IPSP): Opening K+ ion channels results in an IPSP through K+ efflux
  • PSPs are conducted down the neuron membrane
• Ionic Movements during Postsynaptic Potentials
• Termination of PSPs
  • The binding of a neurotransmitter to a postsynaptic receptor results in a PSP
  • Termination of PSPs is accomplished in two ways:
    • Reuptake: The neurotransmitter molecule is transported back into the cytoplasm of the presynaptic membrane
    • Enzymatic deactivation: An enzyme destroys the neurotransmitter molecule located in the synapse, e.g., AChE destroys Ach
• Neurotransmitter Reuptake
• Neural integration
  • Involves the algebraic summation of PSPs
    • A predominance of EPSPs at the axon will result in an action potential
    • If the summated PSPs do not drive the axon membrane past threshold, no action potential will occur
• A Review of the Withdrawal Reflex and the Role of Inhibition
• Mirror Neurons and Single Unit Recording
• Electroencephalogram (EEG): EEG activity is the summed cortical-electrical activity under electrode

Chapter 2: Neurons, Neurophysiology, Synaptic Integration

• Neurotransmitter used by neuron

Chapter 3: Structure of the Nervous System

• Neuroanatomical terms:
  • neuraxis
  • rostral (anterior) vs. caudal (posterior)
  • ventral (inferior) vs. dorsal (superior)
  • ipsilateral vs. contralateral
• Planes of section:
  • In brain: horizontal, transverse (frontal or coronal), sagittal
  • In spinal cord: transverse (cross-section)
• Two nervous systems:
  • central nervous system vs. peripheral nervous system
  • efferent vs afferent
• The meninges:
  • dura mater layer, arachnoid layer, pia mater layer
• Cerebrospinal fluid (CSF) and brain ventricles:
  • choroid plexus, arachnoid granulations
  • lateral ventricles, third ventricle, fourth ventricle, cerebral aqueduct
  • Protective function of CSF
  • Changes in ventricle size can predict disease
• CNS Organization [know basic functions (KBFs) of parts of the brain]:
  • Forbrain
    • Telencephalon
      • Cerebral cortex
        • Sulci, fissures, gyri
        • Lobes and primary cortical regions
          • Frontal: primary motor cortex
          • Parietal: primary somatosensory cortex
          • Occipital: primary visual cortex
          • Temporal: primary auditory cortex

• Diencephalon: Thalamus, Hypothalamus

• Midbrain = Mesencephalon

• Hindbrain
• Spinal nerves
  • Dorsal (sensory) and ventral (motor) roots

• Spinal Cord
• Peripheral Nervous System (PNS)

• Cranial nerves (do not need to know function of each one)
• PNS divisions
  • Somatic
  • Autonomic

• Parasympathetic (energy conserving, for example, activation of digestion,
• Sympathetic [energy expenditure (fight or flight), for example, pupil
• Axons: Nerve (collection of axons outside CNS) vs. Tract (collection of axons inside CNS)
• Cell collections: Ganglion (collection of cells bodies outside CNS) vs. Nucleus (collections of cell bodies

slowing of heart rate)

dilation, increased heart rate, inhibition of digestion].

• Some definitions

inside CNS).

Chapter 6: Vision

• Sensory systems, in general
• Details of the eye

• Afferent vs. Efferent
• Sensory stimuli: mechanical, chemical, thermal, photic

Sensory modalities respond to unique stimuli, have unique receptors, and result in unique sensations.

photic wave forms

• Saccadic, pursuit, vergence
• Ganglion cell layer, bipolar cell layer, photoreceptor layer
• Rods vs. cones (eye/retina photoreceptors)
• Rod and cone outer-segments, photopigments, and visual transduction
• Central fovea vs. peripheral fovea acuity

• Retina

• 1-to-1 photoreceptor-to-ganglion cell relation in fovea
• Many-to-1 photoreceptor relation in periphery of retina
• Visual Pathways

• Retinal ganglion cells  optic nerve  lateral geniculate nucleus of thalamus  optic
• Parvocellular vs. magnocellular
• Contralateral relation between visual hemifield and brain hemisphere
• Primary visual cortex has feature detectors extract different dimensions of visual input.
• For example, object orientation (as discussed in class), shape, color, size, texture, etc. Those dimensions

radiations  primary visual cortex.

• Feature detection
• Visual association cortex
  • Provides higher level analysis of visual input, in general.
• More on ventral stream (What?) processes

are assembled into full percepts through the visual association cortices.

• Dorsal (posterior parietal) vs. ventral stream (inferior temporal): Where? vs. What?

• Fusiform face area (FFA) involved in facial recognition
• FFA may be sensitive to stimuli with which we have expertise, e.g., faces
• Monkey inferior temporal lobe neurons respond best to monkey faces
• The Jennifer Aniston neuron

• Visual agnosias

• Aperceptive visual agnosia vs. associative visual agnosia
• Prosopagnosia: an aperceptive visual agnosia

Chapter 7: Audition and the Bodily Senses

• Sound Waves

• Perceived dimensions of sound wave loudness, pitch, and timbre as reflected by changes in amplitude,
• Outer Ear (pinna, ear canal, tympanic membrane), middle ear (Ossicles: malleus, incus, and stapes), Inner

frequency, and complexity of sound waveforms.

• Divisions of the Ear

ear (cochlea).

• Cochlea, Organ of Corti, auditory hair cells
  • Organ of Corti: Tectorial membrane, cilia (on hair cells), hair cells, basiliar membrane, auditory nerve axons
  • Inner vs. outer hair cells
• Auditory transduction

• Tip links connect clia and can pull open ion channels to allow entry of K+ and Ca+
• More force of fluid movement in cochlea, the more the opening of the ion channels
• Highest frequencies result in activation of basiliar (and tectorial) membranes closest to the

oval window (stapes).

• Progressively lower frequencies result in activation of points along basiliar membrane progressively

further from the oval window, that is, closer to the apex (tip) tip of the cochlea.

• Auditory Pathways
  • Superior olivary nucleus (in medulla & pons; sound localization)inferior colliculus (tectum)medial geniculate nucleus (thalamus)auditory cortex
• Place Coding of Pitch
  • Different sound frequencies produce maximal distortion of different portions of the basilar membrane.
  • High frequencies register near base of basilar membrane with lower frequencies registering closer to apex of basilar membrane.
  • Know concept of tonotopic mapping
• Support for Place Theory
• Analysis of the Auditory System
• Sound Localization
  • For long to medium duration sound < 3000 Hz in horizontal plane: Between-ear differences in arrival times used (computation in superior olivary nucleus).
  • For very short, high frequency sound in horizontal place–Between-ear differences in Intensity used
  • Localization along elevation: Analysis of timbre differences
• Responsiveness of auditory cortex to tones: non-musicians vs. amateur musicians vs. professional musicians.
  • Measured with magnetoencephalography (MEG)—Changes in current result in changes in magnetic field
  • Professional musicians have largest MEG response to tones and largest auditory cortex.
• Changes in Auditory Thresholds With Age and Sex at Different Frequencies
  • Detection requires increase in intensity with age; Greatest loss with age at highest frequencies; Hearing loss greater for males
• Amusia

• Observation of Traveling Waves in Cochlear by Von Bekesy
• Antibiotics: Induce hair cell loss first at base of basilar membrane, which produces a loss of hearing for high frequency sounds
• Cochlear implants restore speech perception by stimulating different regions of the basilar membrane

• The various components of the auditory system determine sound features
• Pitch – place coding; Loudness – frequency coding; Timbre – different frequencies at different places along basilar membrane; Sound location – e.g., differences in arrival time.

• Difficulty discriminating differences in sound frequency / pitch;
• Difficulty identifying and singing simple, well-known songs
• Rhythm is preserved
• 1-5% of population; Evidence that it is genetic—it runs in families
• Neural Basis: Thickening of auditory cortex; Problems communicating between cortical areas (white matter).

• Vestibular System: 2 and 3 Components Of The Inner Ear
• Vestibular Sacs – Gravity, Information About Head Orientation; Function: Balance, Upright Head Position, Eye Movement; Some Stimulation Results In Nausea
• Somatosenses
  • The somatosenses provide information relating to events on the skin and to events occurring within the body
• The cutaneous senses receive various signals from the skin that form the sense of touch
• Kinesthesia provides information about body position and movement

• Semicircular Canals
  • Semicircular Canals detect angular acceleration; Changes In Head Rotation, Not Steady Rotation; Some Stimulation Results In Dizziness, Rhythmic Eye Movements (Nystagmus)

• Touch – Pressure & Vibration; Temperature – Heating/cooling; Pain – Stimuli that damage tissue

(and produce pain)

• Kinesthetic signals arise from receptors located within the joints, tendons, and muscles
• Hairy skin

• Morphology of Skin

• Ruffini Corpuscles – Skin Indentation; Pacinian corpuscles – Rapid vibration; Free nerve endings – Painful stimuli and changes in temperature; Hair Endings – detect movement of the hairs

• Glabrous skin

• Merkel’s Disks – Response to skin indentation (similar to Ruffini Corpuscles in Hairy Skin); Meissner’s Corpuscles –Found in the nipples / respond to brief taps of the skin and low frequency vibration; Pacinian Corpuscles and Free Nerve Endings too

• Cutaneous Senses
• Somatosensory Pathways

• Three different categories of sensation are reported to the brain by receptors localized within skin
  • Touch involves perception of pressure and vibration of an object on the skin
    • For example, Pacinian corpuscles detect deformation of the skin

• The dorsal columns carry information related to touch (precisely localized)
• The spinothalamic tract carries pain and temperature signals (poorly localized)
• Dorsal root (medullamidbrain) thalamus (ventral posterior nucleus)primary somatosensory cortex

• Somatotopic mapping in primary somatosensory cortex and the sensory homunculus in humans and non-human animals
  • Star-nosed mole: Sensory homunculus (slide); Can tactile information be used to substitute for visual information? (video).

• Pain involves an emotional component (that can be used to modify the magnitude of pain perception)

• Analgesia
• Opiates and Pain
• “Vaginal Stimulation—Produced Analgesia in Rats and Humans”

• Analgesia refers to the reduction of the perception of pain

• Analgesia can be induced by external and internal stimuli: Hypnosis, Massage, Acupuncture, Placebo, Attention shifts, Opiates (and endorphins) – Act on opiate (endorphin) neuronal receptors

• Exogenous opiates reduce pain reactivity: Opium, codeine, morphine, heroin

• Brain produces several endorphins (endogenous endorphins)
  • Naloxone reverses opiate activity: Naloxone reversibility is taken as an indication of opiate involvement
    • Focal brain stimulation can reduce pain: Periaductal grey matter (PAG) in particular is effective

• Tail-pinch pain thresholds in rats increase with vaginal stimulation (VS); Naloxone reverses VS-induced analgesia in rats
• Pain thresholds increase as a function of quality and duration of pleasurable VS in humans; no significant change in tactile thresholds as a function of the quality and duration of pleasurable VS.

• Opiates and Analgesia
• “Mixed Feelings” Video
  • Is visual perception dependent on input to the eye? Can tactile information be used to see?

• Painful Stimulus (PS)  Low Pain Threshold
• PS  Morphine  High Pain Threshold
  • Morphine activates receptors that inhibit the experience of pain.

• PS  Morphine + Naloxone  Low Pain Threshold