Sensorimotor interplay in vocal communication

SENSORIMOTOR INTERPLAY IN
VOCAL COMMUNICATION
Ms. Satadru De
M.Phil II year
Dept. of Neurophysiology
NIMHANS
Date: 05.08.2016

Significance of communication in society
Evolution of communication (taxonomical aspects)
Human speech
- History of the development of linguistic studies
- Peripheral phonation system
- Anatomical areas in speech perception
- Functional pathways
- Models
- Anatomical areas in speech production
- Models
Speech Disorders
Aphasias

o The fungal body is made up of a mass of thread-like structure called the
mycelium
o They act as a kind of an underground internet linking the roots of different
plants
o This fungus-plant relationship unit is called mycorrhiza
o Boosts the plant’s immune-system
o Suzanne Simard of British Columbia Univ in 1997 showed the evidence of
mycorrhiza between Doughlas Fir and Paper Birch trees.
“These plants are not really individuals in the sense Darwin thought they
were, competing for survival of the fittest.” –Simard,2011

Jim Westwood (Professor of plant pathology, physiology and weed science) discovered
the fact that plats communicate with each other on a MOLECULAR LEVEL -Science,
August 15,2014
EXCHANGE OF THOUSANDS OF mRNA MOLECULES CREATES AN
“OPEN DIALOGUE” BETWEEN TWO SPECIES.
Westwood examined the parasitic interation between Dodder (Cuscuta pentagona) and
tomato host plant.
Transport of RNA bwetween the two species.
mRNA from dodder “commands” the host plant to perform actions, like lowering the
defense system, via several proteins encoded by the mRNA.

ANIMALS
(honey bees, fishes, songbirds, primates)

Reproduction
Food foraging
Self Defense
-Vocal sounds (Crickets, frogs, monkeys)
- Gestures (honey bees, fireflies)
- Release of pheromones (moths)
The competition for the attention of the opposite sex has developed more
conspicuous signals and evolution of displays, signalling and morphology (Gould
and Gould, 1996).
Sexual competition – an important selective factor
Cues
Simultaneous Sequential
FundamentalNeuroscience,Squire,3rdedn.

Animal communication is mostly innate
Feature detectors in their nervous system that automatically isolate visual and
acoustic stimuli
Fundamental Neuroscience, Squire, 3rd edn.

The amorous hums of the Midshipman Fishes
(Porichthys notatus)
Science, July 18 2008
Andrew H. Bass, Cornell Prof. of Neurobiology and Behavior, New York
University:
- mapped the brain cells of newly hatched larvae using fluorescent dyes, and
compared them to other species
- clusters of cells in the larvaes’ hindbrain that developed into networks
controlling vocalisation
- mainly in rhombomere 8 (origin of CPG) that gives rise to the vocal motor
nucleus
- the neural network for voice production in vertebrates originated with aquatic
animals, and the fundamental attributes are conserved over the entire phylum of
vertebrates.
Please click to see videoPlease click on speaker icon to hear if video isnt runing

Birds have innate songs
Combination instinct and direct innate learning produce different results
Critical period of learning has impact on the perfection of the adult bird’s song
A chick deafened during critical period is unnable to produce even the innate sound
Learning process involves:
- Listening to each member of the species
-Checking to see of they match any element of memorised song
- Discarding unnecessary tones
- Rearranging, scoring and modifying
Component of auditory feedback
system
Evolutionary remnant of the
forward prediction system???

Neural substrates for birdsong
Some of the brain centres involved (White crowned sparrow, Zebra Finch, Canary etc):
HVC (High vocal centre)
RA (Robust nucleus of arcopallium)
DM
nXIIts (nucleus of twelfth cranial nerve)
Uva (Nuc. Uvaformis in thalamus)
CMM (Caudalateral mesopallidium)
NCM (Caudomedial neostriatum)
AFP (Anterior forebrain pathway, part of the basal ganglia circuit)
Area X (in the AFP)
RAm
PAm
LMAN (Lateral magnocellular nucleus of anterior neostriatum)
MMAN (Medial magnocellular nucleus of anterior neostriatum)
Peripheral parts include:
Lungs
Trachea
Syrinx

General neural circuitry for bird song production
HVCUva CMM
Area X
RA Intereurons
DM
nXIIts
NXIIts
(tracheosyrin
geal portion
of CNXII)
Uva Nlf HVC
(Nuc. Interface of neostriatum)
Nottebohm , F. (2005) in “The neural basis of birdsong”, PLoS
Biology, 3 (5).

RAm PAm
Motoneurons in nXIIts Respiratory neurons in brainstem
DM RA
CN SO LL
Mld (avian homologue of inferior colliculus)
Nuc. Ov (avian homologue of MGN)
Field L NCM (activated during conspecific song
perception)
CMM
Reiner et al.,(2004) Songbirds and the revised avian brain nomenclature, in Behavioral neurobiology of birdsong, Sci.,1016,
pp 77-108.

AFP HVC RA
Area X DLM LMAN
DMP MMAN
HVC
Song Output
Reiner et al.,(2004) Songbirds and the revised avian brain nomenclature, in Behavioral neurobiology of birdsong, Sci.,1016,
pp 77-108.

NON-HUMAN PRIMATES
o Most linguistic studies done using Vervets
o Large repertoire of innate calls for social communication (for e.g., 36 signals for 4
types of alarm calls)
o No voluntary control over respiration, vocal tract or vocalisation
o Researchers have tried to teach chimpanzees comm. system comparable to human
speech but with no fruitful results.
o Primate vocal centres lie medially in the Cingulate area, unlike humans who have lateral
cortical areas in speech control
o Motor planning takes place in brainstem
o Auditory cortex perceive conspecific calls
o Specialised nuclei for vocal sound production
o Assymmetry of hemispheres
o Sound perception and production centres overlap

EVOLUTION OF HUMAN COMMUNICATION
The evolution of human communication can be summarized as follows:
Oral Language (30,000 to 100,000 years ago)
Cave Drawings (about 15,000 B.C.)
The Written Word (5,000 B.C.)
The Printing Press (around 1450)
The Telegraph (1844)
The Radio (1920s)
Television (became more wide-spread in the 1950s)
Digital Technology
•The FOXP2 gene (forkhead box P2) has a lineage in Eukaryota; Metazoa; Chordata to
Hominidae; Homo sapiens.
•It is expressed in fetal and adult brain as well as in several other organs such as the lung and
gut.
•It is an evolutionarily conserved transcription factor; autosomal dominant
•This gene is required for proper development of speech and language regions of the
brain during embryogenesis
•Involved in a variety of biological pathways and cascades that may ultimately influence
language development.
Mutations in this gene cause speech-language disorder 1 (SPCH1), also known as
autosomal dominant speech and language disorder with orofacial dyspraxia.

o Saussure founded the study of linguistics in 20th century. Regarded language as a
rule-governed system, much like chess.
o B.F. Skinner (pre and post WW2) founded the paradigm of behaviorism. The
concept of Tabula rasa. Verbal behavior is malleable – initially lacking
structure,richness induced by environment.
o Noam Chomsky (1950’s) – The Chomskyan Nativism, complete contradiction
against Skinner’s behavioral theory.
o John Austin (philosopher) - Speech Act Theory – speech is for action in social
world.
o Howard Patte’s Biosemiotics – “Natural constraints” in evolution reduce the
possibility of evolutionary outcomes. Evolution of spoken language overcame the
natural constraint.
o Paul Broca (1800’s) – discovery of Broca’s area (BA44,BA45) in a patient with
speaking disorder (Broca’s Aphasia).
o Karl Wernicke, Norman Geschwind(late 19th century) – Wernicke’s area (BA22)
and Wernicke’s Aphasia from postmortem study of patient with a different speech
disorder.
o Penfield and Japser (1950) – mapping of brain areas using local anesthesia.
o Juhn Wada (1960) – Wada test using sodium amytal.
Current seminal works on neurolinguistics and
psycholinguistics with fMRI, PET, MEG, SPECT etc can
be credited to Gregory Hickok, Poeppel et al., Nina
Dronkers, Damasio et al.

The peripheral phonation system
Lungs
Larynx
Pharynx
Oral and nasal cavities
Tongue,teeth,lips
•Vowels are “voiced sounds” – have
periodicity;
•Consonants are “unvoiced” – vocal
folds are either fully open /f/, /s/, or
in intermediate position /h/;
•Consonants can be:
Labial - /p/, /b/
Dental - /f/, /v/
Palatal - /sh/
Glottal - /h/
•Natural resonances of the vocal
tract - FORMANTS
Neuroscience, Purves 5th edn

Functionally these areas are connected by a Ventral pathway and a Dorsal pathway
Ventral pathway – Auditory to comprehension
– Local syntactic structure building
Dorsal pathway – Auditory to motor mapping
– Syntactic processing
First dorsal pathway:
TEMPORAL CORTEX PREMOTOR CORTEX
IFC
SLF
Second dorsal pathway:
TEMPORAL CORTEX BA44
Arcuate fasciculus

ANTERIOR INFERIOR
VENTRAL FRONTAL CORTEX TEMPORAL POLE
Inferior frontal cortex Temporal cortex Occipital cortex
Uncinate fasciculus (UF)
Extreme capsule fibre system (ECFS)
Inferior fronto-occipital fasciculus (IFOF)
Anterior temporal cortex Posterior temporal cortex
ILF
MLF

o The Dual-route model of speech processing - acoustic speech must be linked to
conceptual semantic representations,i.e., speech much be understood; the brain must
link acoustic speech information to the motor speech system, i.e., speech sounds must
be reproduced with the vocal tract.
o This paper focuses on two things curently: The Dual stream model as it is
understood till date;
The concept of predictive coding
o Predictive coding is a notion that is focal in both motor control and in perceptual
processing, i.e., in the two processing streams.

THE VENTRAL STREAM:-
1. Dominant processing network for speech comprehension –
lexical,semantic,syntactical;
2. More left lateralised forming a gradient from superior temporal lobe towards ATL;
3. Hierarchically organised – auditory perception starts in the posterior STL and
semantic processing progresses towards ATL.
Posterior Superior Temporal Areas:-
1. Consists of primary and secondary auditory cortices;
2. Belongs neither to ventral or dorsal stream per se;
3. The dorsal and ventral stream diverges from the middle and posterior STS.

Middle and posterior STS:-
1. Speech comprehension network;
2. Post. STS – complex sounds; Middle STS – phonological and sub-lexical
information;
3. Division of labor between left and right STS:-
fMRI studies – left STS in phonetic and phonological processing (Turkeltaub &
Coslett,2010);
right STS responds to all vocal sounds, processing of emotional
prosody (Belin et al., 2004,2011).
Posterior middle and inferior temporal gyrus:-
1. Posterior MTG (BA21)
Posterior ITG (BA20) Lexico-semantic interface;
2. ITG and IFC – lexical system (Hickok & Poeppel, 2007);
3. MTG, angular gyrus, prefrontal areas, posterior cingulate gyrus, fusiform and
parahippocampal gyri – semantic system (Binder et al.,2009);
4. Border of posterior ITG with occipital lobe forms the VWFA – visual stimuli
processing during reading;
5. Anterior area to post. ITG – modality independent (Cohen et al.,2004).

Anterior Temporal lobe:-
1. The posterior-anterior extension of the STG – hierarchy of the ventral stream;
2. More linguistically complex information – greater spread of info. to ATL
IFG, ITG;
3. Sentence processing (Price, 2012) in concert with angular gyrus (Jang et al., 2013);
4. Strongly left lateralised semantic processing.
Inferior Frontal gyrus:-
1. The ventral and dorsal streams terminate in IFG;
2. Serves as a component of speech production;
3. Modality independent lexical processing;
4. BA45 maybe the end point of ventral stream.
Additional Areas:-
1. Supramarginal gyrus – categorical speech perception (Turkeltaub & Coslett, 2010)
2. Angular gyrus – phonological decision making
Semantic and conceptual retrieval
Finger counting, writing, reading aloud
(contd in next slide)

3. Wernicke-Geschwind Model of language (1965)
4. Basal ganglia – processing of emotional prosody
5. Cerebellum – internal model of speech motor control
parietal and cerebellar circuits in sensory-motor coordination:-
Cortico-cortical circuits – motor control at syllable level
Cerebellar-cortical circuits – motor control at phonetic level

THE DORSAL STREAM:-
1. Initially thought to be involved in spatial hearing (Rauschecker,1998);
2. Supports auditory-motor integration (Hickok & Poeppel, 2000,2004.2007);
3. Links speech sounds with the motor system to reproduce sounds with the vocal
tract;
4. Dominating network for repitition learning(sub-lexical);
5. “Goal of speech production is not a motor configuration but to achieve a speech
sound” – Guenther et al.,1998;
6. Integrates the functioning of the following areas: Auditory areas in STS, motor
areas in lateral IFG (BA44), dorsal premotor site and area Spt (Sylvian fissure at
parieto-temporal boundary in left planum temporale) (Hickok et al., 2010);
7. STS codes sensory based representation of speech
Motor regions code motor based representation of speech
(Hickok 2003, 2009, 2011, 2012)
8. Auditory-motor integration in dorsal stream is based on internal forward models.
Spt as a sensorimotor
integration system
transforming sensory
speech
representations to
motor speech acts.

The State Feedback Control Model

The Hierarchical state feedback control model
aSMG anterior
supramarginal
gyrus;
M1 primary motor
cortex;
S1 primary
somatosensory
cortex;
vBA6 ventral BA6

In the left hemisphere:
1. Middle STG/STS
2. Posterior STG/STS (Wernicke’s area)
3. Middle MTG
4. Posterior MTG
5. Posterior fusiform gyrus
6. Posterior IFG (Broca’s area)
7. Ventral precentral gyrus (primary and premotor cortex)
8. Supplementary motor area SMA
9. Thalamus
10. Anterior insula
11. Medial cerebellum
In the right hemisphere:
1. Middle STG/STS
2. SMA
3. Lateral cerebellum
4. Medial cerebellum

The Lemma Model of Speech Production
Cognitive Neuroscience of Language, Kemmerer, 1st edn 2015 Levelt et al., 2001

o Two main subsystems – one for “lexical selection”, i.e., identifying the most
appropriate word in the mental lexicon; and another for “form encoding”, i.e.,
preparing the word’s articulatory shape.
o Conceptual focussing and Perspective taking – to map the expression into a
lexical concept (“thinking for speaking”)
Choosing words that express certain subjective conceptualisations of the situation;
o Lemma selection – the activated target lexical concept is propagated to the lemma
level so that the lemma matches the concept;
o Retrieving morphemic phonological codes – accessing the morphemic
representation and “spelling out” the segmental phonemic content.
- Slips of the tongue may not occur at this level.
- Retrieved incrementally

o Syllabification – ordered phonemic segments of the words are bundled into
syllables yielding a phonological word;
o Phonetic encoding – draws heavily upon the mental syllabary; phonological
representation of a word is matched in each unit with the corresponding syllabary
node;
o Articulation – activated syllable node is sent to the motor system that controls the
vocal apparatus;
o Self monitoring – to detect and correct our own speech errors.
- External feedback loop error detection – monitors auditory
signals of self produced speech;
- Internal feedback loop error detection – monitors the process of
generating phonological words.

Type of disorder Speech Comprehension
Other
diagnoses
Causes/Areas
affected
APRAXIA
Impaired articulation;
errors with consonant
clusters and fricatives
(eg. ‘ch’ of church or
‘strict’)
Intact
Pauses between
syllables and
words; slowed
rate of speech
Broca’s area,left
frontal and
temporoprietal
cortex,regions of
insula, basal ganglia
DYSARTHRIA
Slurred, mumbled
speech difficult to
understand; slow
rate; abnormal pitch
and rhythm
Intact
Limited
tongue,jaw
movement;
hoarse or breathy
voice
Cerebellum,
motoneurons and
skeletal muscles
(seen in PD, HD,
ALS), muscular
dystrophy
DEVELOPMENTAL
STUTTERING
Words or syllables
are repeated or
prolonged
Intact
Talking or
singing in chorus
improves speech
Area Spt; Sensory-
motor integration is
dysfunctional; the
error correction
signal is inaccurate
APROSODIA
Without tone or
expression/
emotions
Intact
Difficulty in
perceiving
emotional tones
Right hemisphere
speech areas/ right
STS

Do lower animals and non human primates suffer
from communication disorders???

Then…..
….and now!
THANK
YOU!

Sensorimotor interplay in vocal communication

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