Neuroanatomy of language functions

• Supported by post-mortemSupported by post-mortem
studiesstudies
• No consistent results – differentNo consistent results – different
types of aphasia share similartypes of aphasia share similar
behavioural disturbancesbehavioural disturbances
‘‘‘‘Anatamo-clinical principles’Anatamo-clinical principles’

Neuro-linguisticsNeuro-linguistics

 Studies the relation ofStudies the relation of language andlanguage and
communicationcommunication to different aspects ofto different aspects of
brain function.brain function.
 It tries to explore how theIt tries to explore how the brainbrain
understands and produces language andunderstands and produces language and
communication.communication.
Neuro linguisticsNeuro linguistics

 This involves attempting to combineThis involves attempting to combine
neurological/ neuro physiological theory
(how brain is structured and how it(how brain is structured and how it
functions) withfunctions) with linguistic theorylinguistic theory (how(how
language is structured and how itlanguage is structured and how it
functions).functions).

Studies of language and communicationStudies of language and communication
afterafter brain damagebrain damage are perhaps the mostare perhaps the most
common type of neuro linguistic studiescommon type of neuro linguistic studies

Let us study
How language is represented in the brain:How language is represented in the brain:
that is,that is,
how and where our brains store ourhow and where our brains store our
knowledge of the language (or languages)knowledge of the language (or languages)
that we speak, understand, read, and write,that we speak, understand, read, and write,
what happens in our brains as we acquire thatwhat happens in our brains as we acquire that
knowledge, andknowledge, and
what happens as we use it in our everydaywhat happens as we use it in our everyday
lives.lives.

1. What about our brains
makes human language
possible –
why is our communication
system so elaborate and so
different from that of other
animals?
Neuro
linguistics

2. Do people who read languages
written from left to right (like
English or Spanish) have
language in a different place
from people who read languages
written from right to left (like
Hebrew and Arabic)?
Neuro
linguistics

3. Does language use
the same kind of neural
computation as other
cognitive systems,
such as music or
mathematics?
Neuro
linguistics

4. Where in your brain is a word that
you've learned?
How does a word ‘come to mind’ when
you need it (and why does it
sometimes not come to you?)
Neuro
linguistics

5. If you know two languages, how do you
switch between them and how do you
keep them from interfering with each
other?
Neuro
linguistics

6. If you learn two languages
from birth, how is your brain
different from the brain of
someone who speaks only one
language, and why? Is the left
side of your brain really ‘the
language side’?
Neuro
linguistics

Neuroanatomy
The study of the
anatomy and
stereotyped
organization of
nervous systems.

Neurochemical
 The science of
neurochemistry studies
the functions of
neurochemicals.
 A neurochemical is an
organic molecule, such as
serotonin, dopamine, or
nerve growth factor, that
participates in neural
activity.

Neurophysiology
The branch of
Physiology that
deals with the
functions of the
nervous system.

Neuranatomical
correlates of
language Functions.

The complexity of human brain and theThe complexity of human brain and the
complexity of language behavior present acomplexity of language behavior present a
major challenge to anyone trying to explainmajor challenge to anyone trying to explain
how the one produces the other.how the one produces the other.

Although the sizes and shapes of theAlthough the sizes and shapes of the
brains of different people vary, just as facialbrains of different people vary, just as facial
features do, the component structures of thefeatures do, the component structures of the
brain are common to all the human beings.brain are common to all the human beings.

The Central nervous System (CNS)
Parts of the nervous system that are encased
in bone
1. Brain
2. Spinal Cord

The Peripheral nervous System (PNS)
All the spinal nerves that innervate the skin, joints,
muscles, etc. and under voluntary control:
Somatic PNS
Neurons that innervate internal organs, blood vessels,
glands, etc. and are involuntary:
Visceral PNS or Autonomic Nervous System (ANS)

 CNSCNS
Nuclei (gray matter) vs. nerve tractsNuclei (gray matter) vs. nerve tracts
(white matter)(white matter)
Brain, functional areasBrain, functional areas
Spinal cordSpinal cord
Blood-brain barrierBlood-brain barrier
Ventricular systemVentricular system
Blood supplyBlood supply
 PNSPNS
Cranial, cervical to sacral nerves,Cranial, cervical to sacral nerves,
autonomic nervesautonomic nerves
musclesmuscles

Describing locations in the brainDescribing locations in the brain

The locations of the layers, nuclei, andThe locations of the layers, nuclei, and
the pathways of the brain can be describedthe pathways of the brain can be described
by their placementby their placement
 with respect to other body parts of the animal,with respect to other body parts of the animal,
 w.r.tw.r.t to their relative locations andto their relative locations and
 w.r.tw.r.t to a viewer’s perspective.to a viewer’s perspective.

Main terminologies used in relation to
other body parts:
 Caudum (Latin: tail)-Caudal
 Rostum (Latin: beak)- Rostral
 Dorsum (Latin: back)- dorsal
 Ventrum (Latin: Stomach)- Ventral
Main terminologies used to
describe in relation to one
another from the frame of
reference of the face:
 Anterior/frontal
 Posterior
 Lateral(At side)
 Medial(Centre of between)
Locations

to describe the direction of the cut, or a section, through the brain from the
perspective of a viewer.
• Coronal: cut in vertical plane , from the crown of the head down.
• Horizontal: cut in the horizon.
• Sagittal: cut in lengthways, front to back, viewed from the ides
• Ipsilateral: on the same side
• Contralateral: opposite to each other.
• Bilateral : structures are bilaterally.
Locations

 Space restrictions force cerebral hemispheres to growSpace restrictions force cerebral hemispheres to grow
posteriorly over rest of brain, enveloping itposteriorly over rest of brain, enveloping it
 Cerebral hemispheres grow into horseshoe shape (b and c)Cerebral hemispheres grow into horseshoe shape (b and c)
 Continued growth causes creases, folds and wrinklesContinued growth causes creases, folds and wrinkles

Brain protection
1.Meninges
2. Cerebrospinal fluid
3. Blood brain barrier

Meninges
1.1. Dura materDura mater: 2 layers of fibrous connective tissue,: 2 layers of fibrous connective tissue,
fused except for dural sinusesfused except for dural sinuses
 Periosteal layer attached to bonePeriosteal layer attached to bone
 Meningeal layer - proper brain coveringMeningeal layer - proper brain covering
1.1. Arachnoid materArachnoid mater
2.2. Pia materPia mater
Note superiorNote superior
sagittal sinussagittal sinus

Dura mater - dural partitions
Subdivide cranial cavity & limit movement of brain
 Falx cerebriFalx cerebri
 In longitudinal fissure;In longitudinal fissure;
attaches to crista galli ofattaches to crista galli of
ethmoid boneethmoid bone
 Falx cerebelliFalx cerebelli
 Runs vertically alongRuns vertically along
vermis of cerebellumvermis of cerebellum
 Tentorium cerebelliTentorium cerebelli
 Sheet in transverseSheet in transverse
fissure betweenfissure between
cerebrum & cerebellumcerebrum & cerebellum

 Arachnoid materArachnoid mater
 Between dura and arachnoid:Between dura and arachnoid: subdural spacesubdural space
 Dura and arachnoid cover brain looselyDura and arachnoid cover brain loosely
 Deep to arachnoid isDeep to arachnoid is subarachnoid spacesubarachnoid space
 Filled with CSFFilled with CSF
 Lots of vessels run through (susceptible to tearing)Lots of vessels run through (susceptible to tearing)
 Superiorly, forms arachnoid villi: CSF valvesSuperiorly, forms arachnoid villi: CSF valves
 Allow draining into dural blood sinusesAllow draining into dural blood sinuses
 Pia materPia mater
 Delicate, clings to brain following convolutionsDelicate, clings to brain following convolutions

Cerebrospinal Fluid
CSF
 Made in choroid plexuses (roofs of ventricles)Made in choroid plexuses (roofs of ventricles)
Filtration of plasma from capillaries throughFiltration of plasma from capillaries through
ependymal cells (electrolytes, glucose)ependymal cells (electrolytes, glucose)
 500 ml/d; total volume 100-160 ml (1/2 c)500 ml/d; total volume 100-160 ml (1/2 c)
 Cushions and nourishes brainCushions and nourishes brain
 Assayed in diagnosing meningitis, bleeds, MSAssayed in diagnosing meningitis, bleeds, MS
 Hydrocephalus: excessive accumulationHydrocephalus: excessive accumulation

CSF circulation: through ventricles, median and lateral apertures,
subarachnoid space, arachnoid villi, and into the blood of the superior sagittal
sinus
CSF:
-Made in choroid plexus
-Drained through arachnoid villus

Blood-Brain Barrier
 Tight junctions between endothelial cells ofTight junctions between endothelial cells of
brain capillaries, instead of the usualbrain capillaries, instead of the usual
permeabilitypermeability
 Highly selective transport mechanismsHighly selective transport mechanisms
 Allows nutrients, O2, CO2Allows nutrients, O2, CO2
 NotNot a barrier against uncharged and lipida barrier against uncharged and lipid
soluble molecules; allows alcohol, nicotine,soluble molecules; allows alcohol, nicotine,
and some drugs including anestheticsand some drugs including anesthetics

Blood-brain barrier
endothelial cells (tight junctions in-between),
pericytes, and astrocytes (end-foot processes)

Anatomical classification
 Cerebral hemispheresCerebral hemispheres
 DiencephalonDiencephalon
 ThalamusThalamus
 HypothalamusHypothalamus
 Brain stemBrain stem
 MidbrainMidbrain
 PonsPons
 MedullaMedulla
 CerebellumCerebellum
 Spinal cordSpinal cord

Parts of Brain
CerebrumCerebrum
DiencephalonDiencephalon
BrainstemBrainstem
CerebellumCerebellum

Usual pattern of gray/white in CNS
 White exterior to grayWhite exterior to gray
 Gray surrounds hollowGray surrounds hollow
central cavitycentral cavity
 Two regions withTwo regions with
additional gray calledadditional gray called
“cortex”“cortex”
 Cerebrum: “cerebral cortex”Cerebrum: “cerebral cortex”
 Cerebellum: “cerebellar cortex”Cerebellum: “cerebellar cortex”
_________________
____________________________
_____________________________

Gray and White Matter
 Like spinal cord butLike spinal cord but
with another layer ofwith another layer of
gray outside the whitegray outside the white
 CalledCalled cortexcortex
 Cerebrum andCerebrum and
cerebellum havecerebellum have
 Inner gray: “Inner gray: “brainbrain
nucleinuclei” (not cell nuclei)” (not cell nuclei)
 Clusters of cell bodiesClusters of cell bodies
Remember, in PNSRemember, in PNS
clusters of cell bodiesclusters of cell bodies
were called “ganglia”were called “ganglia”
More words: brains stem is caudal (toward tail)
to the more rostral (noseward) cerebrum

Ventricles
 Central cavities expandedCentral cavities expanded
 Filled withFilled with CSFCSF (cerebrospinal fluid)(cerebrospinal fluid)
 Lined by ependymal cells (these cells liningLined by ependymal cells (these cells lining
the choroid plexus make the CSF: see laterthe choroid plexus make the CSF: see later
slides)slides)
 Continuous with each other and centralContinuous with each other and central
canal of spinal cordcanal of spinal cord

 Lateral ventriclesLateral ventricles
Paired, horseshoe shapePaired, horseshoe shape
In cerebral hemispheresIn cerebral hemispheres
Anterior are close, separated only by thinAnterior are close, separated only by thin
Septum pellucidumSeptum pellucidum

 Third ventricleThird ventricle
In diencephalonIn diencephalon
ConnectionsConnections
Interventricular foramenInterventricular foramen
Cerebral aqueductCerebral aqueduct

 Fourth ventricleFourth ventricle
In the brainstemIn the brainstem
Dorsal to pons and top of medullaDorsal to pons and top of medulla
Holes connect it with subarachnoid spaceHoles connect it with subarachnoid space

Subarachnoid space
 Aqua blue in this picAqua blue in this pic
 Under thickUnder thick
coverings of braincoverings of brain
 Filled with CSF alsoFilled with CSF also
 Red: choroid plexusRed: choroid plexus
(more later)(more later)
________

Surface anatomy
 GyriGyri (plural of(plural of gyrusgyrus))
Elevated ridgesElevated ridges
Entire surfaceEntire surface
 Grooves separate gyriGrooves separate gyri
AA sulcussulcus is a shallowis a shallow
groove (plural,groove (plural, sulcisulci))
Deeper grooves areDeeper grooves are
fissuresfissures

 GyriGyri (plural of(plural of gyrusgyrus))
Elevated ridgesElevated ridges
Entire surfaceEntire surface
 Grooves separate gyriGrooves separate gyri
AA sulcussulcus is a shallow groove (plural,is a shallow groove (plural, sulcisulci))
Deeper grooves areDeeper grooves are fissuresfissures

simplified…simplified…
Back of brain: perceptionBack of brain: perception
Top of brain: movementTop of brain: movement
Front of brain: thinkingFront of brain: thinking

Cerebral hemispheres: note lobes
 Divided byDivided by longitudinal fissurelongitudinal fissure into right & leftinto right & left
sidessides
 Central sulcusCentral sulcus divides frontal from parietaldivides frontal from parietal
lobeslobes

 Lateral sulcusLateral sulcus separates temporal lobe fromseparates temporal lobe from
parietal lobeparietal lobe
 Parieto-occipital sulcusParieto-occipital sulcus divides occipital anddivides occipital and
parietal lobes (not seen from outside)parietal lobes (not seen from outside)
 Transverse cerebral fissureTransverse cerebral fissure separates cerebralseparates cerebral
hemispheres from cerebellumhemispheres from cerebellum

coronal section
 Note: longitudinal fissure, lateral sulcus, insulaNote: longitudinal fissure, lateral sulcus, insula
 Note: cerebral cortex (external sheet of gray),Note: cerebral cortex (external sheet of gray),
cerebral white, deep gray (basal ganglia)cerebral white, deep gray (basal ganglia)

Cerebral hemispheres
 Lobes: under bones of same nameLobes: under bones of same name
FrontalFrontal
ParietalParietal
TemporalTemporal
OccipitalOccipital
Plus: Insula (buried deep in lateral sulcus)Plus: Insula (buried deep in lateral sulcus)

Cerebral cortex
 Executive functioning capabilityExecutive functioning capability
 Gray matter: of neuron cell bodies, dendrites, shortGray matter: of neuron cell bodies, dendrites, short
unmyelinated axonsunmyelinated axons
 100 billion neurons with average of 10,000 contacts each100 billion neurons with average of 10,000 contacts each
 No fiber tracts (would be white)No fiber tracts (would be white)
 2-4 mm thick (about 1/8 inch)2-4 mm thick (about 1/8 inch)
 Brodmann areas (historical: 52 structurally differentBrodmann areas (historical: 52 structurally different
areas given #s)areas given #s)
 Neuroimaging: functional organizationNeuroimaging: functional organization
(example later)(example later)

 Prenatal life: genes are responsible for creating thePrenatal life: genes are responsible for creating the
architecture of the brainarchitecture of the brain
 Cortex is the last to develop and very immature at birthCortex is the last to develop and very immature at birth
 Birth: excess of neurons but not inter-connectedBirth: excess of neurons but not inter-connected
 11stst
month of life: a million synapses/sec are made; this is geneticmonth of life: a million synapses/sec are made; this is genetic
 11stst
3 years of life: synaptic overgrowth (connections)3 years of life: synaptic overgrowth (connections)
 After this the density remains constant though some grow, some dieAfter this the density remains constant though some grow, some die
 Preadolescence: another increase in synaptic formationPreadolescence: another increase in synaptic formation
 Adolescence until 25: brain becomes a reconstruction siteAdolescence until 25: brain becomes a reconstruction site
 Connections important for self-regulation (in prefrontal cortex) areConnections important for self-regulation (in prefrontal cortex) are
being remodeled: important for a sense of wholenessbeing remodeled: important for a sense of wholeness
 Causes personal turbulenceCauses personal turbulence
 Susceptible to stress and toxins (like alcohol and drugs) during theseSusceptible to stress and toxins (like alcohol and drugs) during these
years; affects the rest of one’s lifeyears; affects the rest of one’s life
 The mind changes the brain (throughout life)The mind changes the brain (throughout life)
 Where brain activation occurs, synapses happenWhere brain activation occurs, synapses happen
 When pay attention & focus mind, neural firing occurs and brainWhen pay attention & focus mind, neural firing occurs and brain
structure changes (synapses are formed)structure changes (synapses are formed)
 Human connections impact neural connections (ongoing experiencesHuman connections impact neural connections (ongoing experiences
and learning include the interpersonal ones)and learning include the interpersonal ones)
adapted from Dr. Daniel Siegel, UCLA

Cerebral cortex
 All the neurons areAll the neurons are interneuronsinterneurons
By definition confined to the CNSBy definition confined to the CNS
They have to synapse somewhere before theThey have to synapse somewhere before the
info passes to the peripheral nervesinfo passes to the peripheral nerves
 Three kinds of functional areasThree kinds of functional areas
MotorMotor areas: movementareas: movement
SensorySensory areas: perceptionareas: perception
AssociationAssociation areas: integrate diverseareas: integrate diverse
information to enable purposeful actioninformation to enable purposeful action

Controlling our behaviour inControlling our behaviour in
response to the social or environmentalresponse to the social or environmental
situation that we are in –situation that we are in – Considerable skillConsiderable skill

Fontal lobeFontal lobe
 Controls our behaviour with respect toControls our behaviour with respect to timetime
and space.and space.
(only with all the relevant sensory and(only with all the relevant sensory and
mnemonic i.e., memory information).mnemonic i.e., memory information).

Subdivisions of the frontal lobe
 In the human brain, the frontal lobesIn the human brain, the frontal lobes
includes all the tissue anterior to the centralincludes all the tissue anterior to the central
sulcus.sulcus.
 It constitutes 20% of the neo-cortex andIt constitutes 20% of the neo-cortex and
made up of several distinct regions aremade up of several distinct regions are
groupedgrouped

 The motor cortex: Area 4The motor cortex: Area 4
 Pre motor cortex:Pre motor cortex:
Lateral Area 6: pre motor cortexLateral Area 6: pre motor cortex
Medial Area 6: Supplementary motor cortex.Medial Area 6: Supplementary motor cortex.
Area 8: frontal eye field.Area 8: frontal eye field.
Area 8A: Supplementary eye field.Area 8A: Supplementary eye field.

 In humans, the lateral pre motor areaIn humans, the lateral pre motor area
expanded as Broca’s area. (Area 44)expanded as Broca’s area. (Area 44)
developed.developed.

 The frontal cortexThe frontal cortex
are multimodal. Cellsare multimodal. Cells
responsive toresponsive to
combinations ofcombinations of
visual, auditory, andvisual, auditory, and
somatic stimuli aresomatic stimuli are
found in the lateralfound in the lateral
pre motor cortexpre motor cortex
Area 6 and Area 46.Area 6 and Area 46.

Connections of the frontal lobe.
 The motor and pre motor area are part of aThe motor and pre motor area are part of a
functional system to control movementsfunctional system to control movements
directly.directly.
 The motor cortex projects to the spinalThe motor cortex projects to the spinal
motor neurons to control limb, hand, andmotor neurons to control limb, hand, and
foot, and digit movements and to thefoot, and digit movements and to the
appropriate cranial-nerve motor neuron toappropriate cranial-nerve motor neuron to
control facial movements. It connects withcontrol facial movements. It connects with
basal ganglia, and the red nucleus.basal ganglia, and the red nucleus.

 The pre motor cortex influences movementsThe pre motor cortex influences movements
directly through cortico spinal projectionsdirectly through cortico spinal projections
or indirectly through projections to theor indirectly through projections to the
motor cortex. It receives projections frommotor cortex. It receives projections from
the posterior parietal areas.the posterior parietal areas.
 The pre motor regions are connected toThe pre motor regions are connected to
areas concerned with the execution of limbareas concerned with the execution of limb
and eye movements.and eye movements.

 The temporal organization of behavior andThe temporal organization of behavior and
the sequential organization is the generalthe sequential organization is the general
function of the frontal lobe.function of the frontal lobe.
 The frontal lobe contains control systemsThe frontal lobe contains control systems
that implement different behavioralthat implement different behavioral
strategies in response to both internal andstrategies in response to both internal and
external cues.external cues.
 These temporal systems are called asThese temporal systems are called as
‘executive functions’ in recent days.‘executive functions’ in recent days.

 Motor cortexMotor cortex: Provides a mechanism for: Provides a mechanism for
executing individual movementsexecuting individual movements
 Pre motor cortexPre motor cortex..
 Selects the movements to be executed.Selects the movements to be executed.
 The movements can be the response toThe movements can be the response to
either internal or external environmentaleither internal or external environmental
cues or stimuli.cues or stimuli.

 Richard Passingham (1993) suggested thatRichard Passingham (1993) suggested that
the pre motor regions functions primarily tothe pre motor regions functions primarily to
choose behavior in response to externalchoose behavior in response to external
cuescues
 Supplementary motor cortex:Supplementary motor cortex: contributioncontribution
to selection of behavior for internal stimulito selection of behavior for internal stimuli
or when there is no any external cues.or when there is no any external cues.

 The limb and eye movements for a stimulusThe limb and eye movements for a stimulus
directed (Area 8) or for internal cues aredirected (Area 8) or for internal cues are
made (Area 8A).made (Area 8A).
 Per Roland (1980): Supplementary motorPer Roland (1980): Supplementary motor
region plays a special role in the selectionregion plays a special role in the selection
and direction of motor sequences. (Moreand direction of motor sequences. (More
activation for 16 sequential movement of aactivation for 16 sequential movement of a
finger than repetitive movements of thefinger than repetitive movements of the
finger).finger).

 The production of the movement sequenceThe production of the movement sequence
was self –paced, or internally driven.was self –paced, or internally driven.
(Counting , days in week, months in(Counting , days in week, months in
calendar etc, or slokas).calendar etc, or slokas).

 The pre motor cortex is activated whenThe pre motor cortex is activated when
movement sequences are paced externallymovement sequences are paced externally
by a cue. (Speaking to the rhythm of aby a cue. (Speaking to the rhythm of a
pulse).pulse).
 Not only are motor acts paced by cues, butNot only are motor acts paced by cues, but
they also can become associated with cues.they also can become associated with cues.
 When the subjects are trained for arbitraryWhen the subjects are trained for arbitrary
associations there is increase in functionalassociations there is increase in functional
activity in the pre motor cortex. (Learningactivity in the pre motor cortex. (Learning
of traffic signals).of traffic signals).

Functions of the Pre frontal cortex

Controls cognitive processes so thatControls cognitive processes so that
appropriate movements are selected at theappropriate movements are selected at the
correct time and place.correct time and place.

It can be due to internal cues or externalIt can be due to internal cues or external
cues or may be made in response to context orcues or may be made in response to context or
self-knowledge.self-knowledge.

 Internal cues:Internal cues:
Temporal memory, a neural record of recent eventsTemporal memory, a neural record of recent events
and their order related to things or to movementsand their order related to things or to movements
and thus derive their information from the object-and thus derive their information from the object-
recognition or motor streams of sensory processing.recognition or motor streams of sensory processing.

 The dorsolateral areas are especially engaged in theThe dorsolateral areas are especially engaged in the
selection of behavior based on the temporal memory.selection of behavior based on the temporal memory.

 External cues:External cues:
People whose memory is defective becomePeople whose memory is defective become
dependent on environmental cues to determinedependent on environmental cues to determine
their behavior.their behavior.
Frontal lobe injury leads to inability to inhibitFrontal lobe injury leads to inability to inhibit
behavior directed to external stimuli.behavior directed to external stimuli.

Learning by association is controlled byLearning by association is controlled by
orbitofrontal cortex.orbitofrontal cortex.

 Contextual cues:Contextual cues:
The choice of behaviors in context requires detailedThe choice of behaviors in context requires detailed
information which is conveyed to the inferior frontalinformation which is conveyed to the inferior frontal
cortex from the temporal lobe.cortex from the temporal lobe.

 Context also means effective context and isContext also means effective context and is
contributed by amygdala.contributed by amygdala.
 Persons with orbitofrontal lesions, whichPersons with orbitofrontal lesions, which
are common in TBI, closed head injury haveare common in TBI, closed head injury have
difficulty with context, especially in socialdifficulty with context, especially in social
situations.situations.

 Autonoetic awarenessAutonoetic awareness
 Lifetime experiences and goals can alsoLifetime experiences and goals can also
influence our behavior.influence our behavior.

 Tulving (2002) called this autobiographicTulving (2002) called this autobiographic
knowledge as autonoetic awareness. i.e.,knowledge as autonoetic awareness. i.e.,
self-knowledge.self-knowledge.
 This allows one to bind together theThis allows one to bind together the
awareness of oneself as a continuous entityawareness of oneself as a continuous entity
through time.through time.
Impairment results in a deficit in the selfImpairment results in a deficit in the self
regulation of behavior.regulation of behavior.

Our behavior is influenced by ourOur behavior is influenced by our
personal past experiences and life goals for thepersonal past experiences and life goals for the
future.future.
Such that we interpret the whole world in ourSuch that we interpret the whole world in our
daily life with in our owndaily life with in our own frame of referenceframe of reference..

Patients with ventral frontal injury often loosePatients with ventral frontal injury often loose
this self-knowledge and have difficulty in dailythis self-knowledge and have difficulty in daily
living.living.

Asymmetry of frontal lobe function

 The asymmetry of functions is relative ratherThe asymmetry of functions is relative rather
than absolute.than absolute.
 Right frontal lobe:Right frontal lobe:
 role in non verbal movements such asrole in non verbal movements such as
facial expressions.facial expressions.
 More engagement in retrieval ofMore engagement in retrieval of
information.information.

 Left frontal lobe:Left frontal lobe:
 role in language, Speech.role in language, Speech.
 Encoding information into memoryEncoding information into memory
Laterality of function disturbed by frontal –Laterality of function disturbed by frontal –
lobe lesions are less striking than thelobe lesions are less striking than the
posterior lobes.posterior lobes.

Heterogeneity of frontal lobe
functions
 Any individual patient is unlikely to show allAny individual patient is unlikely to show all
the symptoms and the severity of thethe symptoms and the severity of the
symptoms may vary with lesion location.symptoms may vary with lesion location.
 However , in recent homogeneity ofHowever , in recent homogeneity of
functions are favored i.e., at least in thefunctions are favored i.e., at least in the
orbitofrontal cortex there is evidence oforbitofrontal cortex there is evidence of
discrete localization of functions.discrete localization of functions.

Symptoms of frontal lobe lesions

Disturbance of motor function
 Damage to Primary motor cortexDamage to Primary motor cortex::
 Chronic loss of the ability to make fine,Chronic loss of the ability to make fine,
independent finger movements ,independent finger movements ,
presumably owing to a loss of directpresumably owing to a loss of direct
corticospinal projections onto motorcorticospinal projections onto motor
neurons.neurons.
Loss of speed and strength in both hand andLoss of speed and strength in both hand and
limb movements in the contralateral limbs.limb movements in the contralateral limbs.
Loss of strength : Area4, lesions restricted toLoss of strength : Area4, lesions restricted to
prefrontal cortex.prefrontal cortex.

 Movement programming.Movement programming.
Removal of supplementary motor cortex-Removal of supplementary motor cortex-
Transient disruption of all voluntaryTransient disruption of all voluntary
movements.movements.
Disrupts copying of the facial movements.Disrupts copying of the facial movements.

 Voluntary gaze and visual search tasks.Voluntary gaze and visual search tasks.
 Corollary discharge or reafferenceCorollary discharge or reafference

 Teuber (1972), argued that voluntaryTeuber (1972), argued that voluntary
movements require two sets of signals.movements require two sets of signals.
 A movement command through motorA movement command through motor
system, effects the movement and asystem, effects the movement and a
signal(Corollary Discharge) from the frontalsignal(Corollary Discharge) from the frontal
lobe to the parietal and temporallobe to the parietal and temporal
association cortex presets the sensoryassociation cortex presets the sensory
system to anticipate the motor act.system to anticipate the motor act.

Speech
 Broca’s areaBroca’s area::
word retrieval on the basis of an object, word,word retrieval on the basis of an object, word,
letter, or meaning. It is like the premotor area’sletter, or meaning. It is like the premotor area’s
role in other behaviors.role in other behaviors.
 Broca’s area selects words on the basis of cues.Broca’s area selects words on the basis of cues.
People with Broca’s area damage are impairedPeople with Broca’s area damage are impaired
in their ability to use verbs and to producein their ability to use verbs and to produce
appropriate grammar, symptom ofappropriate grammar, symptom of
Aggrammatism.Aggrammatism.

 Supplementary Motor Area:Supplementary Motor Area:
Retrieval of words without external cues, whichRetrieval of words without external cues, which
also is consistent with the general function ofalso is consistent with the general function of
supplementary motor area.supplementary motor area.
Damage to supplementary area extended to leftDamage to supplementary area extended to left
medial frontal region are often mute.medial frontal region are often mute.
Ability to speak usually returns in unilateralAbility to speak usually returns in unilateral
region than in bilateral lesion.region than in bilateral lesion.
 Because of bilateral participation ofBecause of bilateral participation of
supplementary motor area in movementsupplementary motor area in movement
selection.selection.

Loss of divergent thinking
List of possible uses of Cup, a frontalList of possible uses of Cup, a frontal
lobe injury interferes with the processlobe injury interferes with the process
required for divergent thinking.required for divergent thinking.

Behavioral SpontaneityBehavioral Spontaneity
 Loss of Spontaneous Speech , word fluencyLoss of Spontaneous Speech , word fluency
testtest
( Patients are asked to write or say as( Patients are asked to write or say as
many as words starting with a given lettermany as words starting with a given letter
as they can think of in 5 minutes and asas they can think of in 5 minutes and as
many as four letter word of a given letter inmany as four letter word of a given letter in
4 minutes).4 minutes).

 Damage to left orbitofrontal and rightDamage to left orbitofrontal and right
orbitofrontal region leads to markedorbitofrontal region leads to marked
reduction in verbal fluency.reduction in verbal fluency.
 The spontaneity loss can be in daily routineThe spontaneity loss can be in daily routine
activities and lethargic too.activities and lethargic too.

Strategy formation:Strategy formation:
 Impairment in developing novel cognitiveImpairment in developing novel cognitive
plans or strategies for solving problems.plans or strategies for solving problems.

Environmental control of
behaviour

 Response inhibitionResponse inhibition
Frontal lobe damage leads to perseverations onFrontal lobe damage leads to perseverations on
responses.responses.
Difficulties in shifting response strategies.Difficulties in shifting response strategies.

 Poor performance inPoor performance in stroop task.stroop task.

 Risk taking and rule breakingRisk taking and rule breaking
Orbitofrontal cortex is part of neural decisionOrbitofrontal cortex is part of neural decision
making circuit that evaluates degrees ofmaking circuit that evaluates degrees of
uncertainty in the world.uncertainty in the world.

 Self regulationSelf regulation
The loss of biographic knowledge clearly makesThe loss of biographic knowledge clearly makes
it difficult to put ongoing life events in contextit difficult to put ongoing life events in context
and leads to difficulties in regulating behaviorand leads to difficulties in regulating behavior
flexibly.flexibly.
Difficulty in regulating own behavior because ofDifficulty in regulating own behavior because of
loss of autonoetic awareness.loss of autonoetic awareness.

 Poor temporal memory.Poor temporal memory.
There is unequivocal role of the frontal cortexThere is unequivocal role of the frontal cortex
in short term memory processes.in short term memory processes.
Different regions of the prefrontal cortexDifferent regions of the prefrontal cortex
control the storage of different types ofcontrol the storage of different types of
information.information.

Area 46 likely plays an important role inArea 46 likely plays an important role in
providing an internal representation of spatialproviding an internal representation of spatial
information, and the medial regions likely playinformation, and the medial regions likely play
a similar role in object formation.a similar role in object formation.
Cells in these area are active during theCells in these area are active during the
intervals in delayed-response tests, and theirintervals in delayed-response tests, and their
activity ends abruptly when an animalactivity ends abruptly when an animal
responds.responds.

Gabriel Leonard (1988) had reported thatGabriel Leonard (1988) had reported that
patients with frontal lobe lesions performpatients with frontal lobe lesions perform
normally on the recognition trials, but they arenormally on the recognition trials, but they are
impaired in judging the relative recency of twoimpaired in judging the relative recency of two
previously seen items.previously seen items.
Asymmetry in functionsAsymmetry in functions
Right frontal lobe: important for memory for non-Right frontal lobe: important for memory for non-
verbal, or pictorial, recencyverbal, or pictorial, recency
Left frontal lobe: important for verbal recency.Left frontal lobe: important for verbal recency.
In contrast, lesions in temporal lobe lesions areIn contrast, lesions in temporal lobe lesions are
impaired in the recognition test but not in theimpaired in the recognition test but not in the
recency test.recency test.

 Impaired social and sexual behaviors.Impaired social and sexual behaviors.
Social and Sexual behaviors require flexibleSocial and Sexual behaviors require flexible
responses that are highly dependent onresponses that are highly dependent on
contextual cues.contextual cues.
Frontal lobe damage leads to a marked changeFrontal lobe damage leads to a marked change
in social behavior and personality. e.g., Phineasin social behavior and personality. e.g., Phineas
Gage case reported by John Harlow in 1868.Gage case reported by John Harlow in 1868.

Pseudodepression/ PseudopsychopathyPseudodepression/ Pseudopsychopathy
Outward apathyOutward apathy
Indifference, loss of initiative, reduced sexualIndifference, loss of initiative, reduced sexual
interest, little overt emotion, little or no verbalinterest, little overt emotion, little or no verbal
output.output.
General lack of social graces.General lack of social graces.

 Spatial DefecitSpatial Defecit
The dorsolateral frontal lobe playsThe dorsolateral frontal lobe plays
an important role in the visuomotoran important role in the visuomotor
guidance of movements in space and inguidance of movements in space and in
mental rotation. ( Per Roland and Larsmental rotation. ( Per Roland and Lars
Friberg,1985).Friberg,1985).

 Damage to Frontal Facial AreaDamage to Frontal Facial Area
- Unilateral removal of the cortical area- Unilateral removal of the cortical area
representing the face results in norepresenting the face results in no
significant chronic loss in sensory or motorsignificant chronic loss in sensory or motor
control of the face, presumably because ofcontrol of the face, presumably because of
the face’s bilateral representation in thethe face’s bilateral representation in the
cortex.cortex.

- It does result in chronic deficits in- It does result in chronic deficits in
phonetic discrimination, spelling, verbalphonetic discrimination, spelling, verbal
fluency and design fluency (Taylor, 1971).fluency and design fluency (Taylor, 1971).

Diseases affecting the frontal lobe
 SchizophreniaSchizophrenia
 Parkinson’s diseaseParkinson’s disease
 Korsakoff’s syndrome ( Chronic alcoholismKorsakoff’s syndrome ( Chronic alcoholism
induced metabolic disorder)induced metabolic disorder)
 Drug addiction (Inability control drugDrug addiction (Inability control drug
seeking behavior) – leads to changes in theseeking behavior) – leads to changes in the
structure of neurons in both thestructure of neurons in both the
orbitofrontal and the medial fontal regions.orbitofrontal and the medial fontal regions.

Frontal Lobe
LocationLocation
 Brodmann Area 6 - AreaBrodmann Area 6 - Area
1010
 Reciprocal connectionsReciprocal connections
with thalamuswith thalamus
FunctionFunction
 Control of fine movementsControl of fine movements
 Cognitive functionsCognitive functions
(Reasoning/Decision(Reasoning/Decision
making/Planning)making/Planning)

Frontal Lobe
LocationLocation
 Brodmann area – 44 ,Brodmann area – 44 ,
45 (BA 44,45)45 (BA 44,45)
 Connection withConnection with
Wernicke’s areaWernicke’s area
FunctionFunction
 Sentence generationSentence generation
 Overt verbal fluencyOvert verbal fluency
 Linguistic processingLinguistic processing
 Phonological ProcessingPhonological Processing

 1,2,3 and 43-1,2,3 and 43-
Somatosensory cortexSomatosensory cortex
 39,40, 5, 7-Posterior39,40, 5, 7-Posterior
Parietal cortexParietal cortex
1
2
3 40
7
5
39
43

 Object RecognitionObject Recognition
 Guidance movementGuidance movement
 SensorimotorSensorimotor
transformationtransformation
 Spatial NavigationSpatial Navigation

Parietal Lobe
LocationLocation
 Central sulcus to OccipitalCentral sulcus to Occipital
lobelobe
 Superior to temporalSuperior to temporal
lobelobe
FunctionFunction
 Integration of sensoryIntegration of sensory
informationinformation
 Visual recognition ofVisual recognition of
actionaction

Angular Gyrus
LocationLocation
 Brodmann area - 39Brodmann area - 39
 ““Association cortex forAssociation cortex for
association cortices”association cortices”
FunctionFunction
 Recognition of visualRecognition of visual
symbolssymbols
 ReadingReading
 Sound spellingSound spelling
correspondencescorrespondences

Supramarginal Gyrus
LocationLocation
 Brodmann area - 40Brodmann area - 40
 Posterior end of LateralPosterior end of Lateral
fissurefissure
 Sensory association areaSensory association area
FunctionFunction
Integration of kinestheticIntegration of kinesthetic
memories with auditorymemories with auditory
commandscommands
 Phonological processingPhonological processing
 Semantic representationSemantic representation

 ““my son’s wife” and “mymy son’s wife” and “my
wife’s son”wife’s son”
 ““tap” and “pat” have thetap” and “pat” have the
same letters, but thesame letters, but the
spatial organization isspatial organization is
different.different.

Temporal Lobe
LocationLocation
 Brodmann area - 41, 42Brodmann area - 41, 42
 Lies within lateral sulcusLies within lateral sulcus
FunctionFunction
 Auditory ProcessingAuditory Processing

Superior Temporal Gyrus
LocationLocation
 BrodmannBrodmann
Area - 38, 22Area - 38, 22
 BA 22 -BA 22 -
Wernicke’sWernicke’s
areaarea
 ReciprocalReciprocal
connectionsconnections
withwith
thalamusthalamus
FunctionFunction
 AuditoryAuditory
languagelanguage
associationassociation
 Analysis &Analysis &
elaboration ofelaboration of
speech soundsspeech sounds
 PhonologicalPhonological
processingprocessing
Buchsbaum, 2001Buchsbaum, 2001

Middle & Inferior Temporal
Gyrus
LocationLocation
 Brodmann Area - 21, 20Brodmann Area - 21, 20
FunctionFunction
•• Listening toListening to
sentencessentences
•• Reading tasksReading tasks
•• Lexical semanticLexical semantic

Temporal lobeTemporal lobe
 Language formulation areaLanguage formulation area
 Basal temporal languageBasal temporal language
areaarea
 Lexical–phonologicalLexical–phonological
retrievalretrieval
 Semantic processingSemantic processing
 Retrieval of the name of aRetrieval of the name of a
conceptconcept
Mummery et al, 1999Mummery et al, 1999
Posterior TemporoparietalPosterior Temporoparietal
CortexCortex
 Auditory processing forAuditory processing for
speech like stimulispeech like stimuli
 Lexical processingLexical processing
 Short term acousticShort term acoustic
storagestorage

Occipital Lobe
 VisualVisual
sensationsensation
 VentralVentral
pathway -pathway -
objectobject
recognitionrecognition
FunctionFunction
 DorsalDorsal
pathway -pathway -
visuallyvisually
guided actionsguided actions
 Letter byLetter by
letter readingletter reading
Shmuelof & Zohary 2005

Arcuate Fasciculus
LocationLocation
 PosteriorPosterior 
temporoparietaltemporoparietal
junctionjunction
 frontal cortexfrontal cortex
 Part ofPart of
superiorsuperior
longitudinallongitudinal
fasciculusfasciculus
FunctionFunction
 Broca’s areaBroca’s area

WernickesWernickes
 Generation &Generation &
UnderstandingUnderstanding

Sub cortical structures
&
Language

Thalamus
LocationLocation
FunctionFunction
 Anterior ventrolateral –Anterior ventrolateral –
Production of repeatedProduction of repeated
erraneous wordserraneous words
 Medial ventrolateral –Medial ventrolateral –
PerseverationPerseveration
 Posterior ventrolateral –Posterior ventrolateral –
Misnaming, OmissionsMisnaming, Omissions

Basal Ganglia
LocationLocation FunctionFunction
Distinct role in LanguageDistinct role in Language
ProcessingProcessing
 PhonologicalPhonological
 Syntactic processingSyntactic processing
 Monitoring theMonitoring the
semantic and lexicalsemantic and lexical
aspectsaspects

Hippocampus
LocationLocation
FunctionFunction
 Bottleneck for languageBottleneck for language
developmentdevelopment
 Verbal memoryVerbal memory
 Language learningLanguage learning
Knecht 2004Knecht 2004

Brain stem
 Language dependentLanguage dependent
operations begin at thisoperations begin at this
level before signal reacheslevel before signal reaches
cortexcortex
FunctionFunction
 Early stages of processingEarly stages of processing
of linguistic &of linguistic &
nonlinguistic inputsnonlinguistic inputs
Krishnan et al, 2005Krishnan et al, 2005

 Non - motor cognitive abilitiesNon - motor cognitive abilities
 Phonological processingPhonological processing
 Verb generationVerb generation
 Antonym generationAntonym generation
Gebhart, Petersen & Thach’02 , Walter & Joanette’07

Task Specific Representation
 Phonology

Task Specific Representation
 Frontal
Operculum
 Anterior STG
 BA 44/45
 Posterior
STG/STS
 Left Inferior
Frontal Gyrus –
phrase
structure
 Syntax processing

 Non-Syntax
processing
Frontal activation
 Semantic
processing
Müller et al.
(2003)
 Phonological
processing
Fiez et al. (1995)

Semantic Word Processing
Visual
processing
Area
•Striate cortex
•Prestriate area
Word processing
Auditory
processing Area
• 1°auditory cortex,
• Temporo-parietal
• Ant. Sup. temporal
• Inf. Ant. cingulate

Prosody
 Right HemisphereRight Hemisphere
FunctionFunction
 Left hemisphereLeft hemisphere
 Supra Marginal GyrusSupra Marginal Gyrus
 Inferior Temporal GyrusInferior Temporal Gyrus
(Ackermann et al., 2001;
Zatorre et al., 2002)

 fMRI: functional magnetic resonance imagingfMRI: functional magnetic resonance imaging
 Cerebral cortex of person speaking & hearingCerebral cortex of person speaking & hearing
 Activity (blood flow) in posterior frontal andActivity (blood flow) in posterior frontal and
superior temporal lobes respectivelysuperior temporal lobes respectively

Homunculus – “little man”
 Body map: human body spatially representedBody map: human body spatially represented
 Where on cortex; upside downWhere on cortex; upside down

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Neuroanatomy of language functions