Neurolinguistics: Brain and Language

Sydney Lamb

Ling/Anth 411

Introduction to the Course

Linguistics 411 – Neurolinguistics

Introduction and Course Outline

Basic Brain Anatomy

What this course is about

Linguistic neuroscience• A physical science of language• Unlike ordinary linguistics

o Most ordinary linguistics focuses on things people say – “texts”

• Linguistic neuroscience focuses on the system responsible for texts

The linguistic system of a person A system in the person’s brain

The linguistic system as an object of scientific investigation

It is represented in the brain

• The brain is a physical object Is it observable?

• Indirect observation Aphasiology

• Study of impaired linguistic systems

Study of unimpaired linguistic systems

• Direct observation Functional brain imaging Intra-operative mapping

The start of the investigation

We have to be realistic We have to start with observable phenomena First observation:

• People talk with one another

• They must have some means of doing so

• Call it the linguistic system The linguistic system must have a location

• It is mainly in the cerebral cortex

• Known from aphasiology

Next steps in the investigation

The cerebral cortex is a network

• Very large

• Dynamic Changes take place in connection strengths

The linguistic system is part of the cortex

• Therefore it is a large dynamic network

• Not necessarily all in one part of the cortex In fact, we know it is not We know from aphasiology that it

• Occupies several different cortical regions

• These regions are interconnected

Linguistic neuroscience

Linguistic neuroscience has a direct relationship not only to cognitive science but also to neuroscience• Therefore, to biology

Unlike ordinary linguistics But linguistic neuroscience provides a

bridge from neuroscience to other linguistic pursuits

Quote from Norman Geschwind

I gather … that the status of linguistic theories continues to be a difficult problem. … I would wish, cautiously, to make the suggestion, that perhaps a further touchstone may be added: to what extent does the theory tie in with other, non-linguistic information, for example, the anatomical aspects of language? In the end such bridges link a theory to the broader body of scientific knowledge. (1964)

The need to be realistic

Operational plausibility

• The linguistic system has to be able to operate Developmental plausibility

• The linguistic system has to be able to be built within the brain of a small child

Neurological plausibility

• A theory of the structure of the linguistic system must have a plausible relationship to what is known about the brain from neuroscience

Information Card..

LastName, FirstName email address

Major(s) Class

Previous linguistics courses Previous neuroscience courses Previous cognitive science courses

Languages

Why this course?

Introduction to the Brain

Brain Anatomywith special attention to

Linguistically Important Systems

The nervous system

Central nervous system

• Spinal cord

• Brain Peripheral nervous system

• Motor and sensory neurons connected to the spinal cord

The brain

Medulla oblongata – Myelencephalon Pons and Cerebellum – Metencephalon Midbrain – Mesencephalon Thalamus and hypothalamus – Diencephalon Cerebral hemispheres – Telencephalon

• Cerebral cortex

• Basal ganglia

• Basal forebrain nuclei

• Amygdaloid nucleus More..

The brain

Medulla oblongata – Myelencephalon Pons and Cerebellum – Metencephalon Midbrain – Mesencephalon Thalamus and hypothalamus – Diencephalon Cerebral hemispheres – Telencephalon

Brain Stem

Alternative partition: Brain stem Cerebellum Thalamus & hypothalamus Cerebral hemispheres

The brain

Medulla oblongata – Myelencephalon Pons and Cerebellum – Metencephalon Midbrain – Mesencephalon Thalamus and hypothalamus – Diencephalon Cerebral hemispheres – Telencephalon

• Cerebral cortex

• Basal ganglia

• Basal forebrain nuclei

• Amygdaloid nucleus

Thalamus and Cortex

We will concentrate on the cortex But the thalamus is also very important

• Relatively neglected

• Too bad! I wish I knew more about it

Metaphor:• The cortex is the orchestra

A very large orchestra • About 30 million members

• The thalamus is the conductor

Also very important: the Basal Ganglia

Two hemispheres

Left Right

Interhemispheric fissure (a.k.a. longitudinal fissure)

Corpus Callosum Connects Hemispheres

Corpus Callosum

Major Left Hemisphere landmarks

Central Sulcus

Sylvian fissure

The Sylvian Fissure

Major landmarks and the four lobes

Central Sulcus

Sylvian fissure

FrontalLobe

ParietalLobe

TemporalLobe

OccipitalLobe

Primary motor and somatosensory areas

Central Sulcus

Sylvian fissure

Primary Motor Area

Primary Somato-sensory Area

Some terms..

Fissures and sulci

• Singular: sulcus – Plural: sulci

• The major sulci are usually called fissures Interhemispheric fissure Sylvian fissure Sometimes the term Rolandic

fissure is used for the central sulcus Gyri

• Singular: gyrus – Plural: gyri

Alternatives terms for some fissures

Interhemispheric fissure

• Also known as Longitudinal fissure Sylvian fissure

• Also known as Lateral sulcus Central sulcus

• Also known as Rolandic fissure

Primary Areas

Primary Somato-sensory Area

Primary Motor Area

Primary AuditoryArea

PrimaryVisual Area

Divisions of Primary Motor and Somatic Areas

Primary Somato-sensory Area

Primary Motor Area

Primary AuditoryArea

PrimaryVisual Area

Mouth

HandFingers

Arm

Trunk

Leg

Higher level motor areas

Primary Somato-sensory Area

Actions performedby hand

Primary AuditoryArea

PrimaryVisual Area

Mouth

HandFingers

Arm

Trunk

Leg

Actions per-Formed by leg

Actions performedby mouth

Two basic language areas

Primary Somato-sensory Area

Primary Motor Area

Primary AuditoryArea

PrimaryVisual Area

Mouth

HandFingers

Arm

Trunk

Leg

PhonologicalRecognition

PhonologicalProduction

Areas important for language

View from the top..

Supramarginal gyrus

Angular gyrus

Principal cortical gyri (schematic)

Arcuate Fasciculus (from langbrain website)

www.rice.edu/langbrain

Where is the linguistic system?

Not in one place, but in several interconnected areas

Language involves operations in multiple cortical modalities Each of them may also have

non-linguistic functions The hypothesis of a “language

organ” is implausible

end