frontal lobe & language

Frontal Lobe & Language

Phineas Gage• Phineas Gage was foreman of a

dynamite crew working for the Rutland and Burlington Railroad in New England when a tapping iron, more than a meter in length and weighing 6 kg. shot through the left side of his head when a spark ignited the dynamite. Recovered in weeks but according to friends "Gage was no longer Gage." childlike, impulsive, given to profanity and drinking. He was fired, worked in a livery stable. then to South America to establish a coach line. Returned 8 years later, dying of epilepsy. He carried the tamping iron with him all those years.

Orbitofrontal cortex

• Orbitofrontal cortex inhibits hypothalamus, the area responsible for basic appetitive behaviors such as feeding, fighting, fleeing, and mating.

• 1890 - Friederich Golz calms dogs by cutting their brains.

• 1935 - Following demonstration by Jacobson and Fulton that frontal lobe mutilation produced a "calming effect" in monkeys, Antonio Egaz Moniz cut the frontal lobes of 20 of his psychiatric patients and reported a similar "calming" effect.

• 1936 - Walter Freeman and James Watts introduce a surgical technique for frontal lobe lobotomy into the U.S.A. Early 'technique' involved drilling burrholes, later Freeman developed his famous transorbital approach pushing literally an icepick into the brain via the eye sockets.

• 1942 - The icepick lobotomy has spread worldwide and by now approximately 5000 people are lobotomised each year during the 1940's!

• 1949 - Egaz Moniz wins nobel prize for his lobotomy techniques.

Neural Darwinism: growth & selection (or exuberance and elimination)

• Gray matter maturation – myelination doesn’t finish in frontal lobe until 30 y or so

• Adults use frontal lobe to recognize emotions; teens use amygdala

• Right DLF – mentalizing & deception

Frontal Lobe Functions• Environmental Control of Behavior• Difficulties using cues from the

environment to direct, control, or change personal behavior.

• Impaired ability to inhibit responses, leading to perseveration.

• Breaking rules and taking risks (e.g. gambling); not following task instructions

• Temporal Memory Impairment • Short-term memory impairment • Judgments about recency

• Impaired Interpersonal Behaviors: Social & Sexual

• Social & sexual behavior inappropriate or altered from previous forms

• Pseudodepression & Pseudopsychopathy

• Motor Function Disturbances• Loss of fine movement • Loss of speed and strength in hand &

limb movement • Poor programming of movements • Poor voluntary eye gaze • Broca's aphasia

• Loss of Divergent Thinking• Frontal lobe damage shows a loss of

divergent thinking in various forms (multiple correct answers).

• Loss of spontaneous behavior, e.g., speaking & verbal fluency, graphic designs & doodling, overall behavioral output (lethargy, initiation of daily routines

• Impaired strategy formation & planning, especially in response to novel situations

• Personality change

• Environmental dependency

• Mood disorders

• OCD

• Poor organizational strategies

• Poor memory search strategies

• Stimulus-bound behavior/environmental dependency

• Impaired set shifting and maintenance

Wisconsin Card Sorting Task

• Response inhibition - perseveration failures

Tower of Hanoi

NAME INK COLORS

GLP

XTPD

RSLGT

ZMQ

WXFG

HLBG

NAME INK COLORS

MAPLE

BAR

HORSE

CHILD

CLOUD

FORK

NAME INK COLORS

GLPXTPDRSLGTZMQSPRHLBGOSLGTZQXRTREYYPWXFG

ROSLGGWLSLPDRSLGTOMQFGYTJBBRSLGTXLLLLFGTLG

WXFGGLPRMSMQLXTPDRSLGTTTGHBGUJULGTZQP

XLLROLGGWLSLPDRGRZMQFGYTJUQELGTLLFGTLG

NAME INK COLORS

REDGREENBLUEBLUEREDBROWNGREENREDGREENBLUEBROWN

REDGREENBLUEGREENBROWNREDBLUEGREENREDGREENBROWN

BLUEREDREDBLUEBROWNGREENREDBLUEGREENREDBROWN

REDBLUEGREENBLUEBROWNREDGREENBLUEREDGREENBROWN

Stroop Task

• Reading is overlearned, difficult to stop

• Meaning of color word competes with ink name when incongruent ink-word correspondence

• Ability to Inhibit Automatic Processes

Frontal Lobe Functions

• Frontal areas modulate and control motor function, emotion, attention and other cognitive activity. – Impairments can be considered specific deficits of control.

• Cognitive Impairment– IQ is unaffected, however subtle cognitive impairments remain.

• Impaired Abstract Reasoning and Hypothesis testing– failure to maintain goal-directed behavior.– inability to perform abstract reasoning (requires complex associations

between semantic elements, identifying super-ordinate categories– failure to generalize experiences into rules or general principles– Mental flexibility (set shifting problems) and distractibility

• Disturbance of Behavior and Personality– lack of originality and creativity– inappropriate emotions and behavior, with little awareness of it – difficulty initiating behavior or stopping when started (perseveration).

• Language Impairment– Low verbal production, little initiation of conversation, sometimes to

mutism.

• Impairment of Social Behavior– deficits in maintaining appropriate social responses. (even minor deviations

in social behavior are noticeable). – generating appropriate behavioral options in social situations and choosing

the best alternative. Often base behavior on concrete simple motivations and cannot comprehend more complex or abstract reasons for acting.

• Confabulation and Reduplication Syndrome– tend to fabricate quick, impulsive answers to questions. – reduplication. Claims current environment (e.g., hospital) is actually another

place. • Impairment of Motor Function

– Problems with highly controlled, volitional components of motor control. • perseveration, incoordination, motor impersistence and hypokinesia as

well as ideomotor apraxia. Worse for opposite extremities. • Impairment of Reflexes

– inhibition of fundamental reflexes such as grasp and sucking. Patient will grasp when palm stroked. Patient cannot release object even when told to attend to the hand. Or patient compelled to suck on an object placed in his/her lips.

Understanding Language

• Speech Origins: phylogeny, ontogeny (glottogenesis)

• Language Acquisition Failures: autism, deaf of hearing parents, feral/neglected, phonological and syntactical problems

• Language Loss: aphasias, hemispherectomy, split brain

• Normal development – individual differences, bilingualism

• Cultural differences• Its use and creation

What is Language?

• Unique to humans or not– Continuity vs discontinuity theories

• Nature of language– What constitutes language?

Essential features

Hockett’s Design Features

• Semanticity -- Specific signals can be matched with specific meanings.

Hockett’s Design Features

• Arbitrariness -- No necessary connection between the form of the signal and the thing being referred to. No resemblance of elements. (Onomatopoeic words are not entirely arbitrary.)

Hockett’s Design Features

• Discreteness -- Basic units of speech (such as sounds) belongs to distinct categories. No gradual, continuous shading from one to another in the linguistic system. Speakers perceive either a [p] or a [b], but not as blend, even if waveform falls somewhere between the two.

Hockett’s Design Features

• Displacement -- Speaker can talk about things which are not present, spatially or temporally.

Hockett’s Design Features

• Productivity -- Human languages allow speakers to create novel, never-before-heard utterances that others can understand.

Hockett’s Design Features

• Traditional Transmission -- Individual is not born knowing their entire communication system (not entirely hard-wired) but must learn much about it to use it.

Hockett’s Design Features

• Duality of patterning -- Discrete parts of a language can be recombined, reordered to create new forms.

Aphasia

• Loss or impairment of language comprehension or production

Aphasias

Broca’snonfluentcompr okrep poor

Wernicke’sfluentcompr poorrep poor

conductionfluentcompr okrep poor

anomicfluentcompr okrep ok

transcortical sensorynonfluentcompr poorrep poor

transcortical motornonfluentcompr okrep ok

Spontaneous Speech

• Fluent versus nonfluent

• Paraphasias

• Word finding difficulties

• Articulation

• Effort

• Prosody

Auditory Comprehension

• Single words

• Phrases

• Whole body commands

• Syntax

• Repetition– Single words– Phrases

• Reading– Single words– Phrases

Token test

Non-fluent Aphasias

• Broca’s aphasia

• Global aphasia

• Transcortical motor aphasia

• Mixed transcortical aphasia

Fluent Aphasias

• Wernicke’s aphasia

• Anomic Aphasia

• Conduction aphasia

• Transcortical sensory aphasia

• Conduction Aphasia– Fluent speech– Good comprehension– Poor repetition– Poor naming

• Possibly lesion in arcuate fasciculus or its connections in inferior parietal lobule

• Wernicke’s Aphasia– Fluent speech– Poor comprehension– Poor repetition– Poor naming

• Posterior superior temporal lobe lesion (first temporal gyrus)

• Broca’s Aphasia– Non-fluent speech– Good comprehension – Poor repetition– Poor naming

• Posterior inferior frontal lesion

• Global Aphasia– Non-fluent speech– Poor comprehension– Poor repetition– Poor naming

• Lesion involves frontal, temporal and parietal lobes, Including Broca’s and Wernicke’s area

• Transcortical Sensory Aphasia– Fluent speech– Poor comprehension– Good repetition– Poor naming

• Lesion in posterior temporo-parietooccipital junction while sparing Wernicke’s area

• Transcortical Motor Aphasia– Non-fluent speech– Good comprehension– Good repetition– Poor naming

• Lesion involves frontal lobe but spares Broca’s area

• Mixed Transcortical Aphasia– Non-fluent speech– Poor comprehension– Good repetition– Poor naming

• Anterior and posterior association cortex lesions while sparing perisylvian language region

• Anomic Aphasia– Fluent speech– Good comprehension– Good repetition– Poor naming

• Temporal or temporo-parietal lesion

The Hierarchy of Language

• Phonology

• Morphology

• Syntax

• Semantics

• Prosody

• Paralinguistics

• Pragmatics

Phonology

• Sound pattern of language, including basic elements (phonemes) and rules of combination

• Analogous to graphemes p vs /p/

• 45 or so English phonemes

• Infants can identify all 60+ human phonemes until age 8 months

Morphology

• Structure of words and rules for building words out of elements

• Morpheme = smallest unit of meaning

• Free vs bound morphemes

• Lexicon – our knowledge of words & word formation rules

Syntax

• Structure of sentences and rules for building propositions from words

• Role of order in changing meaning

Semantics

• Meaning at level of words, phrases, sentences

Prosody

• Alter sounds within phonemic category to change meaning of message – stress, elongate

Paralinguistics

• Non-linguistic sounds, movements, gestures that augment flow of language (body language, vocal qualifiers, intonation)

Pragmatics

• Rules for how literal meaning is altered by social context