1 / 19

Neuroscience in the Classroom

Neuroscience in the Classroom. Hands-On Activities Using Weakly Electric Fish as a Model for the Study of Neurology. November 8th, 2003. Project Background – 21 st Century Biology. (Est. 1991). Allows students to work cooperatively.

leigh
Download Presentation

Neuroscience in the Classroom

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Neuroscience in the Classroom Hands-On Activities Using Weakly Electric Fish as a Model for the Study of Neurology November 8th, 2003

  2. Project Background – 21st Century Biology (Est. 1991) Allows students to work cooperatively Students have completed and designed experiments on projects such as: Brain Awareness Week Zebrafish Weakly Electric fish Telemicroscopy Thigmomorphogenesis Tomography

  3. Project BackgroundProject Objective • Introductory Neuroscience • Muscle Physiology • Anatomy • Biochemistry • Membrane Potential • Sensory Physiology • Behavior • Evolution • Electrical Physics • Scientific Procedure • Scientific Method • Experimental Thought/Scientific Reasoning • Protocol Writing • Scientific Equipment and Techniques • Data Analysis

  4. Project BackgroundThe Electric Fish Model • Historical Applications • Electric Rays to cure health problems • Studied as possible source of electricity • Aided in studies of motor neuron transmissions and electric potential gradients • Current and Possible Applications • Military • Biosensors • Medical

  5. Electric Fish BackgroundEvolution and Habitat Below: Habitat of Weakly Electric Fish. Both orders (mormyriforms and gymnotiforms) live in shallow, murky waters and hide in aquatic vegetation. Above: Electroreceptor Evolution.

  6. Electric Fish BackgroundEigenmannia virescens • Habitat • Member of the Gymnotiform class in South America • Resides principally in the Magdalena and Amazon Rivers • Nocturnal, generally timid • Live in areas of low water flow • Can grow in length to 45 cm • Diet • Generally, the diet for this species is the larvae of small insects • Electric Organ Characteristics • Myogenic electric organ • Emits a wave-type frequency of 300 Hz (low frequency)

  7. Electric Fish BackgroundOrganization of the Nervous System • The nervous system is composed of two parts: • Central Nervous System (CNS) • Peripheral Nervous System (PNS) • The nervous system has three functions: • Sensory Input • Integration • Motor Output

  8. Electric Fish BackgroundA view of a Neuron Below:A computer representation of a neuron. The three types of neurons are sensory neurons, interneurons, and motor neurons. Above: Neurons are made up of three parts: cell body, axons, and dendrites.

  9. Electric Fish BackgroundPhysics Review: Electricity and the Circuit Board Electrical Physics Circuit: path of an electric current Coulomb: unit of electrical charge Voltage: electrical difference, potential between two poles; volts (joule per coulomb) Current: flow of electrical charge; amperes (coulomb per second) Resistance: conductivity of a material; ohms (volt per amp) The Circuit Board Series: circuit where current through each resistor is the same and voltage is proportional to the resistance Parallel: circuit where voltage through each resistor is the same and current is proportional to the resistance.

  10. Electric Fish BackgroundPhysics Review: Circuit Board Left: Capacitors and resistors are used to demonstrate key concepts of electrical physics. Right: Light bulbs are used to show electrical flow and intensity in a series or parallel circuit. They are also considered resistors.

  11. Electric Fish BackgroundThe Electric Organ and the EOD Below: Anatomy of an electric organ. Left: Location of electric organ in the posterior of the fish. Usually has gelatinous texture with a large volume of cellular space. Composed of multinucleated cells myogenically or neurogenically derived.

  12. Electric Fish BackgroundThe Electric Organ and the EOD Right : Electroreceptor located on fish body. Interprets information from the electric field. The two types of electroreceptors are ampullary and tuberous.

  13. Electric Fish BackgroundThe Electric Organ and the EOD Below: Weakly electric fish create a dipole electric field to locate objects, communicate, and navigate.

  14. Electric Fish BackgroundThe Electric Organ and the EOD Above: The electrical field generated by the fish is distorted by nearby objects. A good conductor (i.e. a living organism) is conducive to the electric force. A non-conductor (i.e. a rock) blocks it. The fish decides how to react to an object based on the distortion pattern it creates in the electric field.

  15. Electric Fish BackgroundHummers vs. Clickers Above: All weakly electric fish emit either “hums” or “clicks” as a means of exploring their environment. Clickers emit a short, pulse-like EOD in bursts. Hummers emit a constant, wave-like EOD.

  16. Electric Fish BackgroundThe Jamming Avoidance Response (JAR) • When two fish with nearly the same frequency meet, one fish shifts its frequency slightly higher and the other fish shifts its frequency slightly lower. • The shifts are simultaneous and reflexive. • The process prevents the two frequencies from interfering and jamming each other’s electrical signals, allowing the fish to operate in the same area.

  17. Electric Fish BackgroundVestibular and Acostico-Lateralis System Left: Section of nervous system in inner-ear that controls balance by maintaining the orientation of body. Processes orientation, acceleration, and movement information. The Acostico-lateralis system in fish is housed in the lateral line canal along the sides of the head and body. Electroreceptors are located there as well. Detects water movements.

  18. Electric Fish BackgroundSources and Links • http://www.life.edu/faculty/wilkinson/BSCI338/L11electrosense/ACL11-electro.ppt • http://soma.npa.uiuc.edu/labs/nelson/electric_fish.html • http://www.apta.org/Education/Continuing_Education/onLine_ceu_List/Vestib_Intro/Page_2 • http://www.sdsc.edu/~marty/cmda/jeol4000.jpg • http://www.people.virginia.edu/~mk3u/mk_lab/electric_fish_E.htm • “Echolocation in Fish: The Electric Organ Discharge.” Grass Instrument Company, 1993. • www.enchantedlearning.com/.../ • anatomy/brain/gifs/Neuron.GIF • http://faculty.washington.edu/chudler/gif/spiback1.gif • http://www.easi.org/nape/apslides/26_cns.gif • www.monkeytime.com/sciencemaster/galleries/brain/images/01.jpg • http://www.psy.jhu.edu/~fortune/data.html

  19. Coming Next…Outline of Workshop Activities • Hummers and Clickers • Circuit Board Activity • Model presentation/anatomy • Ice Cube/Vestibular System • Neuron Activity Contact Us! E-mail: 21bio@sidwell.edu Website: http://www.21bio.org

More Related