This operant conditioning protocol quantifies bird behavioral preferences for one bird song over another. We use this method to test the influence of dopamine on song preference in female zebra finches. This protocol was developed by undergraduate students and is relatively easy to use to test auditory preferences in many bird species.
To fabricate an operant conditioning chamber cut a four by five by six inch door on the side of each of two identical 15 by 15 by 17 inch chambers, 2.5 inches away from the center of the cage, between the chambers. Use a separate piece of the shelving to make a door that covers the window and use wire cutters to make a four by six inch opening between the two chambers to allow the birds to move between chambers. In each chamber place any kind of perch that is suitable for the type of bird being tested, 11 inches from the center of the cage and six inches from the bottom of the cage that will span the width of the cage.
Use zip ties to tether the emitter and receiver of the photoelectric sensor on the cage directly above each end of the perch. And place under cabinet LED lights on the top of the cage to provide enough illumination that the animals will move freely between the two side chambers. Place bird seed and water next to each of the perches, and place a speaker at each end of each chamber.
Place anechoic foam on the perimeter of the entire cage, leaving holes for the cage doors and water bottles. Then connect the speaker to an audio amplifier, and connect the audio amplifier to the sound output on a computer. To connect the sensors open the measurement and automation program associated with the digital IO card, and determine the device ID for the IO card within the devices in interfaces.
Select the device pin outs options to determine the port and line number that corresponds to the inputs. Use the test panels as an option to verify that the IO detects when the infrared beam is broken and note the channel and port IDs for each set of sensors. The green indicators on the sensors will change color when the status of the beam is altered.
To set up the sound analysis program open the soundanalysispro. exe file and select the operant devices tab. Check the enable operant training national instruments card installed box and select the appropriate device ID.For each detector indicate the corresponding port in line for the sensors.
In the main window of the sound analysis pro recorder, click train to activate the sensors for the appropriate channels. A yellow button will appear. Select the channel number of interest to record the name of the bird.
In the identification and mode window enter in the bird's identification in the name field. To ensure that sound is played to the speakers manipulate the settings in the output selection tab to select the appropriate speaker and channel that are connected to the speaker. To determine the female birds'side chamber preference first place the female in the testing cage for at least one hour to allow her time to adjust to the cage.
Use a hand or an object of interest to ensure that the finch explores both sides of the chambers through the opening as necessary. In Sound Analysis Pro open the playbacks tab and click sounds. Then select the audio.
wav file to play silence in chamber one and chamber two. In the main tab click reset and start. At the end of the session click stop and record the number of triggers at each perch as displayed in the blue boxes.
Next, under the playbacks tab select the audio. wav file of the partner song to play back the partner song from the side of the chamber with the fewest perch triggers and select an unfamiliar song from the chamber with the most perch triggers. In the main tab click reset and start to begin the one hour song preference test.
Then calculate the chamber and song preference by dividing the number of triggers on the side chamber playing the partner song by the total number of triggers. In this representative analysis paired females preferred their partner's song and a significant difference was observed between the side chamber preference during silence to that observed during song playback. Thus, the female preferentially triggered the song of her partner compared to the song of an unfamiliar male.
When individual naive females were housed with individual unfamiliar males for 24 to 48 hours, and given two subcutaneous injections of the dopamine two receptor agonist quinpirole, the female birds preferred the song of the male they were with for only 24 to 48 hours. Females that were paired with an unfamiliar male for 24 to 48 hours and additionally given saline injections did not have a preference for his song over the song of another unfamiliar male. To ensure there was no difference in the total activity of the females between treatment groups that could account for the difference in song preference, the total number of perch triggers for each group was compared.
As expected the total activity of the birds in any given treatment group was similar. When setting up the sensors make sure that the infrared beam is aligned correctly. Also be sure that each bird triggers a single count when she lands on a perch.
This procedure can be used to understand the neural circuits underlying song preference formation by injecting dopamine agonists directly into specific brain regions.
