Lecture 12 & 13: Patel

Question 1

How are birdsong’s represented?

Answer 1

Firstly by composers due to a lack of technology Nowadays by a sonogram

Question 2

What are the three parts of a sonogram/ bird song?

Answer 2

Notes - individual parts Syllables - a group of notes Phrase- repeated syllables

Question 3

How can you test whether birds learn songs from other birds?

Answer 3

Hand rear the birds in isolation Control the auditory input using a speaker Only test with juvenile birds

Question 4

Do birds learn songs from other birds? Experiments with chaffinches.

Answer 4

Raised with normal songs (adult tutor bird played) - Reproduces this song Raised in acoustic isolation - Produces a song with similar duration and tempo but different notes, syllables and phases Raised with a tutor song of a different but similar species - Learns the other species song (similar template?)

Question 5

Is bird song learnt or innate?

Answer 5

There is a critical window where the juvenile must hear the tutor song to produce the correct song However the bird will still sing if raised in isolation

Question 6

What are the stages of song development?

Answer 6

Sensory period, Sensory-Motor period, Crystallised

Question 7

Describe the sensory period of song development:

Answer 7

Critical window Birds listen and learns tutor song

Question 8

Describe the sensory-motor period of song development.

Answer 8

There is a sub song (soft, variable with rambling syllables). The song is also plastic- requires rehersal. Eventually the syllables and phrases are repeated, refined and can be recognised. Eventually the tutor birds songs is reproduced.

Question 9

Describe the crystallised period of song development?

Answer 9

Song develops characteristic volume, duration, and order Song then cannot be changed.

Question 10

What do sonograms look like throughout the stages of song development?

Answer 10

Decreased reproduction

Formation of distinctive characteristics: notes –> syllables –> phrases

Decreased plasticity

Question 11

What are the different mechanisms of learning bird song

Answer 11

Seasonally closed, age limited, open-ended

Question 12

What is an open-ended learner?

Answer 12

Those birds which are not limited by age to when they can learn a song. Can learn year on year. E.g. lyre bird

Question 13

What is a seasonally closed learner.

Answer 13

Strict seasons for different stages of song development. Once crystallised cant be changed

Question 14

What are age-limited learners?

Answer 14

Song development periods can overlap, but age is important in defining the critical window (first year). Once the song is crystallised it cant be changed.

Question 15

How is a bird song produced?

Answer 15

Air produced from sacs rather than lungs Body wall muscle must be coordinated to expell air from air sacs. Air movement causes tympaniform membranes to vibrate causing the production of sound waves. Internal and external syringeal muscles alter tension of the tympaniform membrane –> altering of vibration freq.

Question 16

How does the brain control birdsong - Posterior vocal pathway?

Answer 16

HVc has cell bodies with axons –> RA –> nXIIts and respiratory control

Question 17

How does the brain control birdsong - Anterior vocal pathway?

Answer 17

Loop between DLM, LMAN and area X

Question 18

What happens if you lesion different parts of the brain? - HVC lesion

Answer 18

Disrupts song production Disrupts the calls already learnt -evidence suggests HVC is always active during bird song not just when singing

Question 19

What happens when the RA is lesioned?

Answer 19

Disrupts the production of birdsong - Active just before singing

Question 20

What do birds learn about their song?

Answer 20

Creative with the songs they hear- improvise, imitate and invent. - out of 200 plastic syllables 45 crystalise (overproduction and reduction) - Phrase number decreases from 3 to 1.

Question 21

How to birds learn about their song?

Answer 21

Action based learning - Position vocalisations are reinforced Vocalisations are compared to a memory template - Listen to the syllables produced and remember the correct ones.

Question 22

How can you test whether birds recognise songs from con-specifics?

Answer 22

Rear song sparrows and swamp sparrows in isolation Expose fledglings to a variety of tape noises (song and swamp)

Question 23

What were the results of testing whether birds recognise songs from con-specifics?

Answer 23

Preffered conspecifics song but also copied features from other species song 20% of the time. - Swamp sparrow song is simpler - Song sparrows learn swamp sparrows syllables if in correct syntax an tempo

Question 24

Do birds appear to have innate templates?

Answer 24

Yes - still sing when raised in isolation (fewer, longer, simpler notes) - isolate songs vary between species

Question 25

How can you experimentally test whether birds need to hear themselves sing?

Answer 25

Remove the cochlea after the sensory learning period but before the senesory motor period - deaf birds songs are fragmented and non specific —> insert diagram

Question 26

What are song selective neurons?

Answer 26

Neurons which are active when the bird hears itself or a con-specifics song.

Question 27

Where are song selective neurons located?

Answer 27

HVc and LMAN - LMAN responds to own songs (order of syllables)

Question 28

What happens if you lesion LMAN?

Answer 28

In juvenile –> inhibition of mature singing In adult –> no change this shows the anterior vocal pathway is involved in learning songs (i.e. forms innate template)

Question 29

How are hormones responsible for singing?

Answer 29

Related to testosterone levels and size of song nuclei —> increase size of nuclei due to neurogenesis and synapse formation occurs during sensory period. Only males sing?

Question 30

How do we know that hormones are responsible for singing?

Answer 30

Castrate a male –> no longer sing Replace testosterone in castred male –> sing Give testosterone to a female –> sing

Question 31

How are testosterone and song crystallisation linked.

Answer 31

Castrated male cannot crystalise an advanced plastic song. Provide testosterone –> crystalisation

Question 32

What links are there between HVc and song repertoire?

Answer 32

Positive correlation Size of HVc increases –> larger song repertoire.