Basics of neurobiology of language

1. Vijay kumar

2. Language is the ability to encode ideas into signals
which will be streamed as speech.
It is one of the important cognitive ability humans
have.
Language is different from thinking or thought.
It involves usage of words which links sounds to the
meaning.

3. Syntax : rules for combining words into phrases and
sentences & determining relations among words.
Phonology : rules combining sounds into a consistent
pattern in language.
Grammer: system specifying how vocabulary units
can be combined into words,phrases & sentences .

4. Descartes gave his description on language 1637
Meynert, Hughling jackson
Paul broca – Broca’s motor speech area 1861
Carl Wernicke – Wernicke’s area for comprehension
in 1874.
Noam chomsky – Father of modern linguistics.

5. Marc D. Hauser et al Science 298,(2002)
.

6. Marc D. Hauser et al Science 298,(2002)
.

7. Language implementation system:
- Broca’s area (Broadmann area no 44)
- Wernicke’s area(Broadmann area no 22)
- Insular cortex
- Basal ganglia
Mediational system:
Regions in temporal ,parietal & frontal association
cortices.
Conceptual system: Higher order association cortices.

8. Marc D. Hauser et al Science 298,(2002)
.

9. Angela D. Friederici, Trends in Cognitive Sciences 2009

10. Lesion studies done by Broca and Wernicke helped to
identify the centers of language.
Later critical analysis of patients using new
techniques changed this view.
Sign language also stimulates the same brain areas
which are stimulated by verbal stimuli.

11. Left cerebral hemisphere is dominant in right handed
individual.
Right cerebral hemisphere is for colouring of language
i.e. adding of emotional intonation for spoken words.
Language centers are more prominent in left
hemisphere.

12. Arcuate fasciculus was the only link between
Wernicke’s area & Broca’s area.
Due to Functional MRI, MEG,Diffusion tensor imaging
tractography neural networks involved in language
processing can be dileneated.

13. Dorothee Saur et al, PNAS 2008

14. Dorsal stream: Responsible for repetition of speech.
Ventral stream: Listening to meaningful speech
Gregory Hickok Phys Life Rev. 2009

15. Dorothee Saur et al, PNAS 2008

16. Linguistic genes:
FOXP2 gene mutation in KE family with Specific
language impairment.
Quantitative trait loci – set of genes which are critical
for language function.
Critical period for language acquisition:
Time window during which proper input signals are
necessary for activation of the genetic programs
underlying the normal development of brain
structures and their functions.
Yuri I. Arshavsky, Brain research review 2009

17. At birth infants exhibits a universal capacity to detect
differences b/w phonetic contrasts used in world’s
language.
Native language phonetic abilities significantly
increase.
Infants make language like sounds at 5-7 months
Babble in syllables at 7-8 months
Patricia Kuhl et al Annu. Rev. Neurosci. 2008

18. Form sentence like streams by first year.
By the end of first year infant brain is primed for
language which it is exposed.
First words are spoken around first birthday.
Patricia Kuhl et al Annu. Rev. Neurosci. 2008

19. Patricia Kuhl et al Annual. Rev. Neurosci. 2008

20. Definition:
Aphasias are language
disorders which are
caused by focal brain
lesions due to stroke or
head injury.
Medical physiology, Ganong 22 nd edition

21. Principles of neuroscience,4th edi ,Kandel

22. Principles of neuroscience,4th edi ,Kandel

23. Principles of neuroscience,4th edi ,Kandel

24. Thank you