Somatic System

• Provides BIDIRECTIONAL control of all voluntary systems
  • (Into CNS from body, reverse)
• 2 divisions:
  • Somatosensory
    • Conveys info FROM SKIN & MS to brain
  • Somatic motor system
    • Transmits information FROM BRAIN TO SKELETAL muscles

Autonomic System

• Provides bidirectional communication BTW BRAIN & smooth muscle, cardiac muscle, gland cells
• 2 Divisions:
  • Sympathetic
    • Fight or flight
    • Response to stimulus
  • Parasympathetic
    • Concerned with VEGETATIVE functions
      • Digestion, glands....

Four regions of nervous system

1. Cerebral Region
   1. Cerebral hemispheres
   2. Diencephalon
2. Brain stem and cerebellar region
   1. Brain stem
   2. Cerebellum
3. Spinal region
4. PNS region

Cerebral Region

• Cerebral hemispheres
  • Cerebral cortex
  • Axons connecting cortex w/ other parts of NS
  • Deep nuclei
    • All 3 = cap over diencephalon
• Diencephalon
  • Thalamus
    • relay station
  • Hypothalamus
    • regulates autonomic function
    • "homeostatic thermostat"
  • Epithalamus
    • Pineal gland here, circadian rhythm, endocrine secretions
  • Subthalamus
    • Controls/contributes to movement

4 D's:

Four symptoms of damage to brain stem

1. Dysphasia
   • Swallowing difficulty
2. Dysarthria
   • Speech motor problems (any language articulation problems)
3. Diplopia
   • Double vision
4. Dysmetria
   • Difficulty motor planning distances

Brain Stem

(Superior to inferior)

1. Midbrain
   • Sensory/motor function
2. Pons
   • Sends movement information
3. Medulla
   • Autonomic stuff

31 spinal region segments

33 vertebrae

PNS

31 pairs of spinal nerves

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

Efferent

MOTOR

Sends commands FROM the CNS TO the PNS

****OUT****

Afferent

SENSORY

Brings info INTO CNS FROM PNS 

***IN****

(Tract= Bundle of axons working together)

Gray Matter

vs

White Matter

Gray

• Mostly cell BODIES
• Information INTEGRATED here

  ---

White

• Composed of AXONS and MYELIN
• Axons RELAYING info among NS parts
• Collection of axons = fasciculus, tract, funiculus, peduncles

Causes of Cortical Dysfunction:

STROKE

Stroke

Focal damage

Most common OT Dx

Ischemia (BLOCKS)

- 80% of all strokes

- Damage is result of BLOCKAGE of blood (O_2, nutrients, waste removal) supply to brain

»Thrombosis

Vessel that supplies blood gets OBSTRUCTED (Carotid)

»Embolism

Foreign thing (clot) traveling in blood supply causes blockage

("Thrombosis=There" ie originates in brain)

Hemorrhage (BLEEDS)

-Bleeds in brain that damage tissue

»Subarachnoid Hemorrhage

-Bleed located between Arachnoid and Pia Mater

»Intracerebral Hemorrhage

-Damaged caused by ↓BP in brain (Decreased flow to other brain areas)

-Increased cranial pressure due to pooling of blood=damage

Ischemia (BLOCKS)

- 80% of all strokes

- Damage is result of BLOCKAGE of blood (O_2, nutrients, waste removal) supply to brain

»Thrombosis

Vessel that supplies blood gets OBSTRUCTED (Carotid)

»Embolism

Foreign thing (clot) traveling in blood supply causes blockage

("Thrombosis=There" ie originates in brain)

Hemorrhage (BLEEDS)

-Bleeds in brain that damage tissue

»Subarachnoid Hemorrhage

-Bleed located between Arachnoid and Pia Mater

»Intracerebral Hemorrhage

-Damaged caused by ↓BP in brain (Decreased flow to other brain areas)

-Increased cranial pressure due to pooling of blood=damage

• Anoxia
  • Lack of O₂ to brain
  • MORE DIFFUSE DAMAGE AREA
• TBI
  • Falls
  • MVA
• Cerebral palsy
• Inflammatory disease
• Toxic and metabolic diseases
  • West Nile
  • Meningitis
• Brain Tumors
  • Malignant
    • Astrocytoma: Most common
    • Glioblastoma: Aggressive
    • Metastatic: Originated elsewhere
  • Benign
    • Meningioma
    • benign tumors can grow and cause damage that way even if they aren't spreading
• Brain Atrophy
  • Dementia

Lobes (From largest to smallest, superficial to deep)

Frontal

Parietal

Temporal

Occipital

Limbic

Insular

Sulci/Fissures

Longitudinal F

Central S

Lateral S

Parietooccipital S

Gyri

Precentral

Postcentral

Subcortical White Matter:

Types of White Matter Fibers

From longest to shortest:

1. Projection
   
2. Commisural
   
3. Association

PROJECTION FIBERS

• Longest
  
• Axons connecting subcortical structures with cerebral cortex (ie Cortico-spinal tract)
• Form the ascending and descending tracts

COMMISURAL FIBERS

• Intermediate Length
  
• Axons connecting the two cerebral hemispheres (usually homologous areas)
  
• Example: Corpus Collusum, anterior commisure

ASSOCIATION FIBERS

• Shortest Fibers
• Axons connecting gyri in the same hemisphere

LONG                                                     SHORT              

Connects different                                  Within same lobe

lobes                                                        (Gyri to Gyri)

(Frontal to Parietal)

1. Primary Areas
   • Initial sensory detection
     • Sound
2. Secondary Association Areas
   • Integration area
     • Dog bark vs Doorbell
3. Tertiary Association Areas
   • Complex integration of multiple cortical areas
     • eg when a song "takes you back"

Frontal:

3-2-1

(This makes sense because motor PLANNING must occur PRIOR to movement)

Parietal, Temporal, Occipital:

1-2-3

*Primary areas = symmetrical in both hemi's*

*Secondary areas= tend to be adjacent to their 1° areas*

Primary Motor Cortex

______ Lobe

Location

Function

Dysfunction

Primary Motor Cortex

Frontal Lobe

Location: Precentral Gyrus

F(x): Muscle contraction

         Execution of movement

-Motor Homunculus

Dysfunction

Hemiparesis:

One-sided dysfunction

Low tone, spasticity, paralysis, etc

Severity and type of damage correlates to area damaged

Dysarthria:

Speech disorders resulting from:

Paralysis

Incoordination

Spasticity of speaking muscles

PREMOTOR (secondary) CORTEX

             Lobe

Location

Function

Dysfunction

PREMOTOR (secondary) CORTEX

Frontal Lobe

Location: Anterior to Primary Motor Cortex

Function:   Coordinates movement

Control of gross or postural movements

Develops programs for motor routines for

skilled voluntary actions

Dysfunction:

Apraxia: (Motor coordination dysfunction)

Disorder of skilled, purposeful movement

Not caused by deficits in primary motor cortex or comprehension problems

Motor Apraxia:

Loss of kinesthetic memory patterns so that PURPOSEFUL MOVEMENT CANNOT BE ACHIEVED 

IDEA AND PURPOSE OF TASK IN TACT

Premotor Perseveration:

Compulsive repetition of the same movement

"Mmmmmargret" example Kathy gave

Motor Apraxia & Premotor Perseveration often comorbid due to anatomical proximity

FYI:

DYSpraxia= haven't developed a skill

Apraxia= loss of skill

SUPPLEMENTAL MOTOR CORTEX

______ LOBE

LOCATION

FUNCTION

DYSFUNCTION

SUPPLEMENTAL MOTOR CORTEX

Frontal Lobe

Location: Anterior to motor area, on medial side of hemi

Function: Drive for the INITIATION of movement

Dysfunction: Initiation problems; can't get started

MOTOR SPEECH AREA

(Broca)

______ Lobe

Location

Function

Dysfunction

MOTOR SPEECH AREA

(Broca)

Frontal Lobe

Location: Inferior frontal gyrus of the LEFT cerebral hemi

Function: Planning movements of the mouth during speech

  Grammatical aspects of speech

Dysfunction: Broca's Aphasia

Difficulty expressing one's self using language

Motor planning of speech is impaired

Comprehension and control of muscles for other actions (chewing, etc) still IN TACT

Speech presents as choppy, difficult to get out: "car.... crash... hurt"

Premotor Perseveration

Compulsive repetition of the same movement

"Mmmmmargret" example Kathy gave

Prefrontal Perseveration

Compulsive repetition of same task

Eg. Brushing teeth. Terminating. Go to wash face but instead begin brushing teeth again

Dysfunction:

Premotor Cortex

VS

Prefrontal Cortex

PREMOTOR CORTEX                      PREFRONTAL CORTEX

-Motor Apraxia                                     - Ideational Apraxia

-Premotor Perseveration                       - Prefrontal Perseveration

PREFRONTAL CORTEX

DORSOLATERAL FRONTAL CORTEX

______ LOBE

Location

Function

Dysfunction

PREFRONTAL CORTEX

DORSOLATERAL FRONTAL CORTEX

Frontal Lobe

Location: Anterior to premotor cortex

Function: Concerned with EXECUTING GOAL-DIRECTED

ACTIVITIES ("Executive functions")

Dysfunction:

Ideational apraxia

Prefrontal perseveration

Intellectual deficits

Sequencing & organizational deficits

Poor judgment (affects safety)

Loss of abstraction (concreteness)

Bradykinesia w/ L CVA

Impulsivity w/ R CVA

(Impacts safety)

Poor problem solving

IDEATIONAL APRAXIA

IDEATIONAL APRAXIA

BREAK DOWN OF KNOWING WHAT NEEDS TO BE DONE

COMPREHENSION DIFFICULTY

INAPPROPRIATE TOOL USE

Prefrontal Cortex

ORIBITOFRONTAL CORTEX

______ LOBE

Location

Function

Dysfunction

ORIBITOFRONTAL CORTEX

Frontal Lobe

Location: Base and medial aspect of the frontal lobe

Function: Tertiary association cortex of limbic system

Involved w/ consciusness/arousal

Personality

Emotions

Memory

Dysfunction:

Arousal deficits

eg. volitional dysfucntion

Personality/Emotional distrubances

eg. Lability, Apathy

Impaired Judgment

Lack of Insight

Memory deficits/Confabulation

Filling in memory gaps

1. DORSOLATERAL FRONTAL CORTEX
   
2. ORBITOFRONTAL CORTEX

Prefrontal Speech Deficits

Prefrontal Speech Deficits

Echolalia

Repeats words

Anomia

Difficulty naming

Paraphasia

Misuse or replacement of words

(Saying brother instead of sister)

Primary Sensory Area

______ Lobe

Location

Function

Dysfunction

Primary Sensory Area

Parietal Lobe

Location: Post central gyrus

Function:     Detection of touch,

Conscious proprioception

Kinesthesia (Movement sense)

SENSORY HOMUNCULUS

Dysfunction: Lack of sensation to contralateral side

Secondary Sensory Association Area 

_____ Lobe

Location

Function

Dysfunction

Secondary Sensory Association Area 

Parietal Lobe

Location: Superior Parietal Lobe

Function: Coordinates

Integrates

(and) Refines perception of sesory input

***Making sense of sensation***

Dysfunction: Impaired or absent:

- Localization

- 2-point discrimination

- Sharp/dull discrimination

- Stereognosis

- Graphesthesia

Tertiary Association Area

Location

Function

Dysfunction

Tertiary Association Area

Location: Inferior PARIETAL lobe

Function: Complex functions that REQUIRE INTEGRATION of P,T,O

lobes

Dysfunction: APRAXIA

- Motor

- Ideational

- Constructional

*Inability to construct 3-D designs

-Dressing apraxia

PERCEPTUAL DEFICITS

- Figure-ground deficits

- Spatial positioning, position in space...

- Unilateral spacial neglect

- Body scheme disorders

- Somatoagnosia

* can't recognize body part as own

* typically w/ sever hemiparesis

- L/R discrimination

LANGUAGE DEFICITS

- Wernicke's/receptive aphasia

- Agraphia

* Difficulty writing

- Alexia

* Reading

- Acalcula

Primary Auditory Cortex

Temporal Lobe

Location: Superior temporal gyrus

Function: Reception of auditory information

Dysfunction: Decreased hearing acuity in both ears

-Greater loss to contralateral side

Secondary Association Area

Temporal Lobe

Location: Wernicke's area

Function:     Language comprehension

Sound modulation

Perception of music

Auditory memory

Dysfunction: In Dominant/Left hemi:

- Unable to understand spoken language

- Deficits in discrimination of phonemes

In Non-Dominant/Right hemi:

- Impairment in discriminating tones

- Impairment w. loudness

Tertiary Association Area

(part of limbic association cortex)

Location: Temporal Pole

Function:     Memory

Emotional behavior

Personality

Motivation

Dysfunction: Memory deficits

- Verbal and visual memory

- STM and LTM

- Retrograde memory loss

*Loss of memory prior to trauma

- Anterograde memorry loss

* Can't remember moving forward

Emotional disorders

Personality disorders

Visual Association Area

 and

Tertiary Association Area

Visual Association Area and Tertiary Association Area

Occipital Lobe

Location

Adjacent to the primary visual area

Function

Synthesizes visual information and integrates it

Aides in the formation of visual memory

Dysfunction

Visual object agnosia

Not being able to recognize an object

Prosopagnosia

Can’t recognize faces

Left brain damage

• Right sided paralysis and or sensory loss
• Speech and language deficits
• Slow, cautious behavior
• Memory deficits
• Helpful hints: Show these individuals how to do something, do not use language. .. Best to give commands and limit language.

Right brain damage

• Left sided paralysis and/ or sensory loss
• Spatial-perceptual deficits
• Quick-impulsive behavior
• Memory deficits
• Helpful hints: Use language when describing things, do not demonstrate….  Stay away from viso-spatial descriptions.

Blood Supply to Brain

2 Internal Carotid Arteries

+     2 Vertebral Arteries

4 Total arteries supplying brain

L & R vertebral arteries merge to form ________

L & R vertebral arteries merge to form BASILAR ARTERY

Basilar Artery terminates by bifurcating into ________

Basilar Artery terminates by bifurcating into POSTERIOR CEREBRAL ARTERIES (PCA)

ACA supplies______

ACA supplies  MEDIAL SURFACE of cerebral hemispheres

 MCA supplies __________

MCA supplies LATERAL SURFACE of cerebral hemispheres

PCAs supply ______

PCAs supply POSTERIOR surface of hemispheres ESPECIALLY medial and basilar surf.

Circle of Willis

2 Internal Carotid Arteries

2 Anterior Cerebral Arteries (ACA)

2 Posterior Cerebral Arteries (PCA)

2 Posterior Communicating Arteries

1 Anterior Communicating Artery

9 Total Arteries = Circle of Willis 

of

ACA Occlusion- Location of Damage

ACA Occlusion- Location of Damage

• Medial and Superior
  • of FRONTAL AND PARIETAL

1. Lateral Ventricles
2. Intraventricular Foramina
3. 3rd (THIRD) Ventricle
4. Cerebral Aqueduct
5. 4th (FOURTH) Ventricle
6. Lateral and Medial Foramina
7. Subarachnoid Space