Electric Fish Essay

Many people may ask the question: why study such an exotic sensory system such as the electrosensation in electric fish? Could it be because of the natural curiosity that we as human’s exhibit, or maybe because we are intrigued by the various morphological and physiological adaptations that are seen across a plethora of environments? Well, more evolved organisms have achieved their higher traits not from new mechanisms that spontaneously appeared, but from old mechanisms that they share with simpler organisms. Therefore, it is through the study of simpler process that humans hope to better understand their own complex process. Electric fish have perfected the analysis of temporal information and have shown that they can very easily decipher …show more content…
The behavioral aspect was resolved by using Eigenmannia and placing them in chambers of dimensions 26 X 12.5 X 12 cm (Bullock and others, I., 1972). The central compartment that held the fish in place was 22 X 6.5 X 3 cm which was just big enough to hold the fish in place (Bullock and others, I., 1972). This sub-chamber was defined by a plastic screen (Bullock and others, I., 1972). Two pairs of electrodes were built into chamber, one at the ends, and one into the sides (Bullock and others, I., 1972). The electrodes at the end were used to record the fish’s EOD, while the side electrodes were used to propagate the stimulus (Bullock and others, I., 1972). This procedure allowed them to determine many aspects of the JAR behavior. Specifically, they revealed that the time it took to elicit the response to a jamming stimulus was between 25 to 35 seconds, with a half time commonly between 10 and 15 seconds (Bullock and others, I., 1972). Furthermore, Bullock and his colleagues were able to determine that when the stimulating frequency was modulated 10 Hz above and below the fish’s frequency, the response was dependent on the span, symmetry around the response, voltage, and modulation (as shown by Figure 1) (I., 1972). Since the behavior is dependent on many aspects of the signaling stimulus, it has been observed that shifts sometimes occurs toward it instead of away. This phenomenon is termed the negative JAR, and was attributed to high intensity stimuli (Bullock and others, I., 1972). It was also noted that when this modulation of 10 Hz above and below the fish’s EOD continued for several minutes, the response was consistent (Bullock and others, I., 1972). However, there was an individual-dependent settling down period in which the magnitude of each period fluctuated by 50% (Bullock and others, I., 1972). This period was