Development of Vocalisation and Speech Flashcards
What do syllables consist of?
Phonemes
What is the innate part of language?
At birth can discriminate phonetic units forming building blocks for phonemes
What is the learnt part of language?
Sensory - at 6 months discrimination of phonetic categories and phrases of native language - patterns of phonemes
Social - motherese - stretches acoustic space, emphasises phonemic distinctions, new vocabulary in stereotyped way
Sensorimotor - control vocal cords to make certain sounds
In what way is birdsong hierarchical?
Sequence of phrases before pause - phrase consists of syllables - syllables consist of notes
Give an example of a songbird species that learns its song
US swamp sparrow
What is the sensory learning component in a US swamp sparrow?
Gains memory representation of song template - subsong
What is the sensorimotor learning component in a US swamp sparrow?
Control vocal apparatus - match vocal output to template
What is the crystallisation component in a US swamp sparrow?
Song expression becomes stable
What is an age-limited learner in birds, and give an example species
Hearing only important during song acquisition -deafening after crystallisation has no effect on song
US song sparrow
What is an open-ended learner in birds, and give an example species
Songs differ between years - must learn new songs
Deafening after crystallisation deteriorates song in weeks
Canaries
What is the common audio input pathway in birds?
Cranial nerve VIII input - via cochlear nucleus - higher vocal centre (HVC)
What is the anterior forebrain pathway in birds?
HVC - area X - dlm - LMAN - robust nucleus
What is the song motor pathway in birds?
HVC - robust nucleus - hindbrain
How does brain circuit development enable sensory learning in birds?
HVC enables learning of song template - no anterior forebrain pathway / song motor pathway
How does brain circuit development enable sensorimotor learning in birds?
Practice refines subsong production
Weak song motor pathway connections modified by anterior forebrain pathway - reward of correct vocalisation - NMDA-dependent
How does brain circuit development enable crystallisation in birds?
HVC takes control via song motor pathway - anterior forebrain pathway not needed
What is the effect of switching off the HVC with optogenetics when the pupil sings and what does this show?
Decreases similarity to tutor’s song
HVC critical for acquiring template from tutor
What is the effect of disrupting pupil’s HVC activity when singing certain syllable?
Later general song production unaffected - poor production of previously-disrupted syllable
What is the effect of a anterior forebrain pathway lesion?
Minimal effect of adult song
Freezes song development
What is the effect of switching off the LMAN (output component) in adults and what happens after it is switched back on?
Sensorimotor learning can still occur - prevents changes in song production
Immediate presentation of effects of sensorimotor learning
What are the different types of vocalisation in human speech development and when do they occur?
0-3 months - non-speech sounds 3-7 months - vowel sounds 7-10 months - babbling 10-12 months - language-specific speech 12 months - words
How does social interaction aid human language learning?
Visual input - e.g. gesturing to object of conversation
Interactive - adjust speech if listener not understanding
How does brain activation change in response to speech after the 1st year in humans?
Initially only Wernicke’s area
After 1 year also Broca’s area
What is the human equivalent of the HVC?
Premotor cortex
