Neurophysiology lab

Virtual Neurophysiology Lab

Definitions of Key Terms

• Voltage
    - Definition: The electrical potential difference between two points.
    - Explanation: It represents the amount of work needed to move a unit of electric charge between those two points.

• Membrane Potential
    - Definition: Refers to the difference in electrical charge between the inside and outside of a cell membrane.
    - Explanation: This difference arises due to the unequal distribution of ions (charged particles) across the membrane, leading to a polarized membrane.

• Resting Potential
    - Definition: The membrane potential of a cell at rest.
    - Explanation: It is the electrical charge inside the cell when it is not actively transmitting signals, such as writing a message.

• Action Potential
    - Definition: A rapid, short-lasting change in the electrical potential across a nerve cell membrane.
    - Explanation: It is how neurons transmit signals, and ganglion polarization is a key part of the action potential.

• Ganglion
    - Definition: A cluster of nerve cell bodies located outside the central nervous system (brain and spinal cord).
    - Explanation: Ganglia act as relay stations for nerve signals.

• Dorsal
    - Definition: Refers to the back or upper side of an organism.
    - Explanation: In the nervous system, it often refers to structures located toward the back of the body or spinal cord.

• Ventral
    - Definition: Refers to the front or lower side of an organism.
    - Explanation: In the nervous system, it often refers to structures located toward the front of the body or spinal cord.

• Electrode
    - Definition: A conductor through which electricity enters or leaves an object, substance, or region.
    - Explanation: Electrodes are used to measure electrical activity in specific areas or to stimulate them.

Mechanoreceptor Response

• T Mechanoreceptor
    - Function: Responds to touch.
    - Initial Response: Responds first to light force.
    - Importance for Animals:
      - Detection of subtle changes in the environment can be crucial for survival.
      - Assists in sensing prey, predators, or navigating terrain.

Neuron Classification and Function

• Sensory Neurons
    - Four Identified Sensory Neurons: T (Touch), P (Pressure), N (Extra Pressure), R (nervous-system related).
    - Identification Rationale: Based on the types of stimuli they respond to (light/touch, medium/pressure, heavy/extra pressure).

• Motor Neuron Identification
    - Identified Neuron: X is a motor neuron.
    - Conclusion Rationale: It lacks sensory receptors and does not react to physical stimuli.

Leech Dissection Experiment

• Leech Dissection Overview
    - Task: Follow all slides showing how the leech is dissected for the neurophysiology experiment.
    - Experiment Setup: The dorsal side is oriented up, and the skin is cut open along the dorsal midline.
    - Focus Area: The ventral nervous system is being studied.

• Mapping Neurons on the Ganglion
    - Objective: Map locations of different types of nerve cells on a ganglion in the dissected piece of leech.
    - Report Documentation:
      - Print a report after completing the lab.
      - Document work by taking a photo of identification in front of the report or screen showing results.

• Identified Neuron Types:
    - N, T, P, R, X.
    - Observed different responses to light (brush), medium (probe), and heavy (forceps) force applied on neurons.

Pain Receptor Analysis

• Nociceptor Response
    - Definition: N is identified as a nociceptor or a pain receptor.
    - Response to Force: Responds first to heavy force.
    - Importance:
      - Signals potentially damaging stimuli, enabling the animal to feel pain.
      - Critical for avoiding contact with harmful objects, restricting movement for healing, and other survival-dependent responses.