1	SENSORY PHYSIOLOGY BIOLOGY 305 LABORATORY
2	LAB PRACTICAL Be Sure YOU Know: How to log on How to load software & settings (tutorial) How to set up hardware How to use the finger pulse transducer (w/o noise) How to avoid Aliasing How to determine a sufficient sampling rate How to change the display time/resolution (zoom) How to define & calculate: Period, Frequency, HR How to analyze a trace in the Analysis Window How to print & use the Journal
3	THIS WEEK: REFLEX & REACTION TIMES Stimulus – Response Pathways:
4	THIS WEEK: REFLEX & REACTION TIMES Investigation of Reaction Times: Audio Stimuli Visual Stimuli
5	THIS WEEK: REFLEXES & REACTION TIMES Investigation of Reaction Times: Possible Influences: Efferent pathway NOT a likely influence
6	THIS WEEK: REFLEX & REACTION TIMES Reflex: Stereotypical, rapid motor response Does not require input from brain
7	NEXT WEEK: THE CRAYFISH STRETCH RECEPTOR CRAYFISH: Invertebrate in phylum Arthropoda subphylum Crustacea Also includes: barnacle, crab, crayfish, lobster, shrimp Scientific name: Procambarus clarkii Largely aquatic Characteristics include: Hard exoskeleton Jointed, paired appendages Three body regions
8	THE CRAYFISH STRETCH RECEPTOR Crayfish Nervous System: Bilateral Symmetry Segmented Arrangement: Each body segment contains a ganglion Axons carry info between ganglia Nerve roots branch off ganglia to periphery Contain sensory & motor neurons
9	THE CRAYFISH STRETCH RECEPTOR Purpose of Exercise: Gain experience w/ classic neurophys. prep. Investigate stimulus-response properties of crayfish nervous system Observe characteristics of crayfish sensory system Differentiate responses from two types of sensory organs
10	THE CRAYFISH STRETCH RECEPTOR Muscle Receptor Organs (MROs): Located in abdomen Composed of a sensory neuron & an associated muscle Two types: MRO1 & MRO2
11	THE CRAYFISH STRETCH RECEPTOR Superficial Extensor Muscle: Two per abdominal segment Each contains 2 MROs,
12	THE CRAYFISH STRETCH RECEPTOR When Abdomen of Crayfish Bends: S. extensor muscle is stretched Sensory neuron receptors activated
13	THE CRAYFISH STRETCH RECEPTOR Signaling: Electrical signals (GP) are generated by stretch sensitive dendrites Action potentials (APs) produced at trigger zone
14	THE CRAYFISH STRETCH RECEPTOR For This Exercise: We’ll record extracellularly from nerves that carry sensory info from MROs to CNS Accomplished by curling crayfish tail to stimulate sensory receptors
15	THE CRAYFISH STRETCH RECEPTOR Major Instruments: Suction Electrode Micromanipulator Dissecting Scope
16	THE CRAYFISH STRETCH RECEPTOR Major Instruments: Pre amplifier/filter Digitizer (iWorx Unit) Computer Audio Amplifier
17	THE CRAYFISH STRETCH RECEPTOR Exercises: Increasing Stimulus Intensity Observe MRO₁responses (freq) to sm, med, and large stimuli (stretch) Adaptation Experiment Observe responses to a stimuli of long duration and fixed intensity Tapping Experiment Elicit MRO1 & MRO2