Sensation and Perception (II)3270

Speech

Keywords on hearing (introduction)auditory canal, ear drum, ossicles, oval window, cochlea, helicotrema, basilar membrane, tectorial membrane, hair cells, kinocilium, stereocilia,

amplification (by ossicles & area difference between ear drum and oval window), travelling wave, resonance, tonotopic coding, cochleotopic coding, transduction

auditory thresholds, effect of age, different animals, fundamental, harmonics, timbre, pitch/frequency, loudness/amplitude, pure tone, equal loudness, masking

place theory, periodicity theory, duplicity theory, missing fundamental, goldfish has no basilar membrane - can distinguish freqs, phase-locking, diplacusis,

PHONEMES

sounds that create meaning

47 in English

VOICINGPLACE OF MANNER OFARTICULATIONARTICULATION

voicedalveloar ridgestop unvoicedlabiodentalfricativeetcnasaletchttp://nationalstrategies.standards.dcsf.gov.uk/node/85357

time Formant 3 Formant 2 Formant 1

Formant transitionsFormantsSEGMENTATION PROBLEM

Segmentation problem

Where one sound is influenced by what sound came before or after because of CO-ARTICULATION

Same sounds, different spectrographs...VARIABILITY PROBLEM

IS SPEECH SPECIAL?

MOTOR THEORY OF SPEECH

-- mirror neurones?

http://www.teachersdomain.org/asset/hew06_vid_mirrorneurons/

IS SPEECH SPECIAL?

2. CATEGORICAL PERCEPTION

Voice Onset Time (VOT)ShortVOTLongVOT

SAMEDIFFERENT

IS SPEECH SPECIAL?

3. SPEECH PERCEPTION IS MULTIMODAL

McGurk Effect

Video demos

1. McGurk effect

video=gasound = bacombo= da

2. Vision helps degraded sound

IS SPEECH SPECIAL?

4. Are there INVARIANTS for phonemes?

-- practical importance-- some hints-- varied by neighbouring sound-- different conditions eg. speed of speech-- different speakers-- but TOP DOWN INFLUENCES

TOP-DOWN INFLUENCES

Segmentation influenced by meaning

Anna Mary Candy Lights Since Imp PulpLay Things.

I scream, you scream, we all scream for ice cream!!

TOP DOWN INFLUENCES

Segmentation influenced by meaningSemantics (meaning) and syntax (grammar) both influence your ability to shadow (repeat what you have heard) a text.

percent correct89%79%56%normal sentencesanomalous sentencesungrammatical sentences

TOP DOWN INFLUENCES

Segmentation influenced by meaningSemantics (meaning) and syntax (grammar) both influence your ability to shadow (repeat what you have heard) a text.Phonemic restoration.

Time to meet with their respective legi laturess time to aves the countryw the flagPink noise demo: http://www.youtube.com/watch?v=k74KCfSDCn8Legislatures: http://www.youtube.com/watch?v=UlJs24j3i8E&feature=related

SUMMARY Is speech special?

Motor theory of speechCategorical perceptionMultimodal aspectsInvariantsTop down influences(i) Segmentation influenced by meaning(ii) Shadowing influenced by meaning(iii) Phonemic restoration

PHYSIOLOGY OF SPEECH PERCEPTION

Might there be phoneme detectors in the brain?Voice onset time (ms)020406080Percentage heard as da100%50%0%Percentage heard as ba0%50%100%/da//ba/

ADAPT TO /ba//ba//ba/

/ba//ba//ba//ba//ba//ba//ba//ba//ba//ba/

After adapting to /ba/Voice onset time (ms)020406080Percentage heard as da100%50%0%Percentage heard as ba0%50%100%

As if that wasnt cool enough..

What happens after adapting to a McGurk effect?

Sound = /ba/

Vision = /ga/

Perception = /da/acousticperception

After adapting to McGurkVoice onset time (ms)020406080Percentage heard as da100%50%0%Percentage heard as ba0%50%100%??

It is the ACOUSTIC signal that adaptsVoice onset time (ms)020406080Percentage heard as da100%50%0%Percentage heard as ba0%50%100%

Brocas aphasia http://www.youtube.com/watch?v=f2IiMEbMnPMWernickes aphasia http://www.youtube.com/watch?v=B-LD5jzXpLE

Cells in cortex show:

Phoneme information carried in a population code

Special features in auditory cortex (eg, frequency sweeps) compatible with phonemic features

Background resting activity -- note more activity in frontal regionsGreen = averageblue = lessred = more

Looking aroundFrontal eye fieldsVisual cortex

Listening to words

Counting out loud

Internal speech -- counting in your head?????

Internal speech -- counting in your headFrontal regionsNOTBroca or Wernickesareas !!!!

olfactory binding protein, olfactory receptors cells continuously regenerate (about every 60 days), cilia (on olfactory receptor cells), glomerulus (contact zones between receptor cells and mitral cells:plural glomeruli), convergence (1,000:1), mitral cell, olfactory tubercle of cortex (part of paleocortex), medial dorsal nucleus of thalamus , orbitofrontal cortex, olfactory neocortex

paleocortex associated with limbic system, limbic system associated with emotions (electrical stimulation causes sham rage), limbic system associated with memories (H.M. had lesions here and lost the ability to memorize things), some hot spots in olfactory tubercle and on olfactory mucosa

KEYWORDS -- SMELL I

odour quality, no primaries identified in olfactory system, poor tuning of receptors (to chemicals or chemical types) (sharpened by lateral inhibition, inhibitory interneurones, granule cells), Henning smell prism, stereochemical theories based on lock and key partially successful, BUT no receptor sites identified, similar shaped molecules can be associated with different smell perceptions

cells broadly tuned (responding to many different chemicals associated with many different smells)

codingintensity= firing rate/recruitment, quality = distributed pattern code, problems in identifying many smells at once, binding problem KEYWORDS -- SMELL II

odour thresholds, olfactorium; unique technical problems!, humans very sensitive (eg. mercaton can be detected at 1 part per 50,000,000,000), affected by gender; can be affected by menstrual cycle, affected by age

adaptation, thresholds raised (by exposure), masking (by other chemicals), some cross effects: eg. adapting to orange affects smell of lemons

identification, can identify gender from shirt, prefer own odours, odour memories long lasting; associated with emotions (via limbic system) "designed not to forget, pheromones, releasers (immediate effect), eg. bitch on heat, territorial markers, humans?, McClintock effect (synchronized menstrual cycles), primers (longer term) eg. mice need males around for proper oestrus cyclesKEYWORDS -- SMELL III

PATHWAYS olfactory receptor cells to mitral cells in olfactory bulb to olfactory tubercle in paleocortex THEN

1 to medial dorsal thalamus to olfactory cortex (ORBITOFRONTAL CORTEX) 2 to limbic system 3 brain stem pathways associated with pheromones

ALSO

inhibitory pathway (via inhibitory interneurone: granule cells) from one olfactory bulb to the other to do with detecting the DIRECTION from which a smell originates KEYWORDS -- SMELL IV

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