Periplaneta Americana Experiment

The content of this section depends to a large extend on the nature of the experiment. Topics here should include a section labelled:

Action potentials can occur more frequently as long there is a continued source of stimulation, as long as the relative refractory period has been reached, which in experiment 2 the refractory period was complete.

In this weeks reflection I will be using the AFY100 textbook chapter five, as well as the Practical guide to Bolt action rifle Accurizing and Maintenance pages 1-44 as reference material.

Figure 1. A Comparison of a CAP Recording of an Earthworm to an Intercellular Recording. The “taller” graph is a depiction of a microelectrode recording of an action potential inside a neuron. The highlighted graph is a depiction of an extracellular recording suction electrode on a giant earthworm. The dotted line represents the minimum voltage needed to depolarize an action potential. The results are obtained from a PowerLab Data Acquisition Unit and a LabChart computerized software. The data are recorded in units of milliseconds and millivolts.

- I also tested the headstage configuration suggested by the Neuronexus representative for Ground and reference connection via the signal generator.

Another research arena is the area origin of these tinnitus producing changes, whether it is induced at one level, and then relayed to other levels, or at all levels of auditory pathways; more specifically the critical elements within the neuronal circuit. Research is needed to separate the mechanisms of tinnitus induced with salicylate, quinine or intense sound from those induced by ear infection, head trauma and other ototixicities. We need to account for the hyperactivity of the central auditory system in the absence of corresponding change in the auditory nerve. Evidence is abundant from human brain imaging studies demonstrating involvement of central structures not only in the inferior collculus, dorsal cochlear nucleus and auditory cortex but also linked to the limbic system associated with emotion and somatosensory areas. That would be the most surprising turn in the tinnitus research which is the discovery of the influence of non- auditory parts. Equally intriguing is the question about any accompanied changes in chemistry and gene structure with tinnitus, which can help in the development of effective drug therapies. It is widely agreed upon that tinnitus can be the result of imbalance in the excitatory and inhibitory

The snail like shape of the cochlear effectively boosts the strength of the vibrations caused by sound, especially for low pitches. When sound waves hit the ear drum, tiny bones in the ear transmit the vibrations to the fluid of the cochlea, where they travel along a tube that winds into a spiral. The tube’s properties gradually change along its length, so the waves grow and then die away, much as an ocean wave travelling towards the shore gets taller and narrower before breaking at the beach.

There are several specific questions this paper seeks to answer. One question is about animal models. They are often used as stand-ins for studying humans. These animal models provide much of the foundation of our understanding about the effects of noise in the elderly. Several animal studies will be examined, and the similarities and difference will between them will be compared, and the limitation of the aplicibility of animal model to human research will be discussed.

An eel was placed in a naturalistic experimental environment with other fish and the fishes’ response to high-voltage pulses was observed. If there was a strong enough discharge, the fish was unable to move on its on accord and was captured by the eel. A pitched fish was placed behind an agar barrier, which received the same discharge as the eel directed toward earthworms placed in the same environment. In order to determine if the discharges induced the muscle movement by initiating action potentials or by activating the motor neurons in the fish, two fishes were pitched; one of the fish was injected with an AcH antagonist and the other was injected with a placebo. To test doublet and triplet discharges

The instruments used in this experiment is an analytical balance to ensure precision. In order to

Hypothesis:The specific receptors on the antennas on the insect's head bind to molecules in the air. The neurons that correspond to these receptors send messages about this binding to the brain and allow the insect to perceive the sound.

The EEG recordings where collected with the Quickcap using twenty-six electrodes located to the 10-20 system. The data was recorded at sample rates

This experiment shall be repeated twice or more to enhance accuracy of the results obtained. Besides detecting systematic errors, this experiment would aid on the technique and understandings to the correct use of these equipments.

The compound action potential adds up all the action potentials that each individual neuron experiences in the sciatic nerve. Different stimulus amplitudes cause different neurons to fire an action potential; this is due to the fact that each neuron has a different threshold potential, or the minimum voltage the neuron needs to fire an action potential. The individual neuron action potential is an ‘all-or-nothing’ event, but the CAP, as a summation of different individual neurons, is not. The CAP amplitude will increase with larger stimulus potentials because more neurons with higher individual thresholds will be recruited. For this frog sciatic nerve, there are three fiber types, A, B, and C. A fibers are further divided, in the order of decreasing diameter, into α, β, γ, and δ fibers. There is an inverse relationship between the diameter of the nerve fiber and the threshold potential: the larger the diameter, the lower the threshold. Thus, as the largest fibers, the Aα neurons will be the first to be stimulated at a low stimulus potential, and the Aδ neuron fibers will be the last to be recruited. Because the sciatic nerve is mostly composed of A fibers, the recruitment of A-subtype nerve fibers are more readily distinguishable from the data. The minimum potential required to stimulate the Aα fibers was between 75 mV and 80 mV. Once the stimulus potential reached 90 mV, Aβ neurons were recruited and contributed to the increase in amplitude of the CAP. At a stimulus

The neurons in the brain tissue communicate with each other via electrical signals, generating measurable action potential activity. Electrophysiological techniques have been developed to measure this electrical activity. Electrophysiological techniques are some of the classic methods of brain research, partly because they are very sensitive and accurate. They provide quite a number of insights into the subject’s mind as well as allow for study of how the brain works. They can be used during brain surgery as well as when the patient is awake and conscious, as the brain itself does not sense pain during the measurements. Although electrophysiology has been around for close to half a century, it has attained appreciable advances only in the last two decades. These advances have revolutionized the study of brain structure and functions, allowing neurophysiologists to monitor the brain’s activities directly during experiments (Sutler et al., 1999). Even with its significant impact in neurology, however, its presence has been so commonplace that many people no longer realize its ubiquity. This essay explores three electrophysiological techniques namely patch clamp, sharp electrodes, and brain slice recording. It describes how each of these techniques works as well as how advances in the techniques have