Electric fish

Unwelt

An organisms unique sensory world

Echolocation

High intensity sound wave (not always ultrasound) to analyze echo for the purpose of orientation

Electolocation

The capacity to perceive weak electric fields

Echolocation and electrolocation are types of

Active orientation mechanisms

Sensorimotor integration-simple

1. Sensory

2. Afferent neuron

3. CNS

4. Efferent neuron

5. Effector organ

Corollary discharge

From motor output to sensorimotor processing; subtracts the predictable component of sensory input (selfgenerated) from the overall sensory input received (external)

What is the importance of GCaMP?

Visualizes if a neuron was activated. In other words, it visualizes if there was calcium entry, indicating the release of neurotransmitters.

Chemical synapse

Where a chemical neurotransmitter is released

What does the mouse study tell us about neuron modulation?

The mouse study was conducted by teaching mice to tap something with their whiskers and they would be given water as a reward. Neuron activation was visualized using GcAMP. The whisker graphs showed that there is modulation of motor and sensory due to learning. If there wasn’t modulation, then the angles of movement of whisker would be the same for motor and sensory.

Strongly electric fish

Have their electric organs cover a large portion of their body

How do weakly electric fish locate food?

Their electric organ generated an oscillating electric field. A rock distorts field, reducing the density of the field across the body. A fish INCREASES local field density.

How does the jamming avoidance response work?

If the neighbor fish frequency is higher than the fish’s own frequency, then the “own” fish will lower its discharge frequency, while the higher frequency neighbor raises its even more.

How does the fish determine the sign of the frequency difference?

The fish compares its own frequency with the COMBINED frequency of both fishes.

Phase delay

If the combined frequency pits are happening after the “own” fish’s frequency, then the “own” fish will respond with a phase delay

Phase advance

If the combined frequency pits are happening before the “own” fish’s pits, then the “own” fish will respond with a phase advance

Phase influence on amplitude

Amplitude differs at point 0, where both fish’s waves equal the same frequency, AND the phase may differ from either side.

TU electroreceptor organ

Receptor is tuned in to alternating-current, or the current of both the “own” fish’s and the “mixed” current.

Phase and amplitude encoder are

Independently processed from the hindbrain to the midbrain which will follow either the decrease or increase frequency pathway