Lecture 11 - Language (Cognitive Neuroscience, UU)

Phonology: the study of the abstract sound patterns of a particular language, usually according to some system of rules.

Syntax: the rules for arranging items into their possible permissible combinations in a language.

Semantics: the analysis of the meaning of a language.

Language is a system of discrete infinity. There is a finite number of elements, but unbounded use of those elements.

Human language is grounded on a particular computational mechanism, realized neurally. Each expression is assigned an interpretation at two interfaces.

There is a sensitive period for learning a 2^nd language:

Language wars:

• Language involves Universal Grammer
• Language acquisition is usage-based through statistical learning.

Language has a hierarchical structure.

Aphasia: an impairment in language understanding and/or production that is caused by brain injury.

Damage to Broca’s area and Wernicke’s area is different and expresses itself differently. The damage is always on the left side of the brain, because language is lateralized.

Late 20^th century view:

• Broca’s area: syntax
• Wernicke’s area: lexicon

Contemporary view:

There are two networks; in the frontal and temporal lobes. They interact all the time. There are interactions through dorsal and to ventral pathways.

Neural mechanisms for syntax and hierarchical structures

• Assembly of hierarchical structures involves Broca’s area
• Complex sentence proceeding involves VA 44 and STC via their dorsal connection
• STC supports integration of syntactic and semantic information to achieve sentence interpretation
• STS-PMC connection is present at birth and supports auditory-based phonological learning, but NOT complex syntax

Newborn’s Wernicke’s area is not yet connected to Broca’s area. But it is connected to the premotor cortex.

So there is a sensory-to-motor mapping system. And there is a dorsal system (syntax, hierarchical structures) and ventral system (processing of semantic information.

Ability to imitate sounds is necessary for language in humans. Not in monkeys.

Convergence: different species have come up with similar solutions for similar problems.

2 month old infants: the brain responds more to the sound of the mother than a stranger (is related to memory).

FOXP2 gene mutation causes aphasia to develop. Other animals can have this mutation as well. It is however not a language gene, because:

• Genes make proteins, not behavior
• FOXP2 affects other genes
• Whatever effect it has is in combination with numerous other genes
• Mutation has multiple effects, not only on speech.

Conclusions:

• Language is not the same ass peech or communication
• Language is a computational system, in the mind
• Broca’s & Wernicke’s area / aphasia
• Language is lateralized neurally
• It involved complex interactions between frontal and temporal networks
• Language likely evolved very recently, only in humans.

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