Download primary motor cortex

Homework Week 2
 Due in Lab
 PreLab 2
 HW #2 – Synapses (Page 1 in the HW Section)
Reminders
No class next Monday
Quiz 1 is @ 5:30pm on Tuesday, 1/22/13
Study guide posted under “Study Aids” section of website
Thought Questions
When you have one of your mandibular teeth
worked on at the dentist and he gives you a shot to
deaden half of your mouth, what division of the
nervous system is being affected by the lidocaine?
2. What do you think it’s mode of action is?
1.

Hint: Remember Physio-EX in lab?
3. Is it affecting a cranial or spinal nerve?
Thought Questions
What 3 structures maintain resting membrane
potential in neurons?
2. What membrane structure is responsible for
depolarization during an action potential?
3. What membrane structure is responsible for
repolarization during an action potential?
1.
The Nervous System
THE CENTRAL NERVOUS SYSTEM
THE BRAIN
Introduction
 Integration
 Memory
 Learning
 Sensation and perception
Organization of Neural Tissue
 White matter versus gray matter
 Fiber bundles
 Nerves versus tracts
 Nerve cell bodies
 Nucleus versus ganglion
Organization of Neural Tissue

Generally


External white matter


Central cavity surrounded by a gray matter core
Composed of myelinated fiber tracts
Brain has additional areas of gray matter

Not present in spinal cord
Cortex of
gray matter
Inner gray
matter
Central cavity
Migratory
pattern of
neurons
Cerebrum
Cerebellum
Region of cerebellum
Outer white
matter
Gray matter
Central cavity
Inner gray matter
Outer white matter
Brain stem
Gray matter
Central cavity
Outer white matter
Spinal cord
Copyright © 2010 Pearson Education, Inc.
Inner gray matter
Figure 12.4
Organization of Neural Tissue
Similar pattern with additional areas of gray matter
The Brain
 Functions
 Conscious perception
 Internal regulation
 Average adult male 3.5 lbs
 Average adult female 3.2 lbs
Same brain mass
to body mass ratio!
The Brain
4 Adult brain regions

1.
2.
3.
4.
Cerebral hemispheres (cerebrum)
Diencephalon
Cerebellum
Brain stem (midbrain, pons, and medulla)
The Brain
The Brain
 Four major regions are connected by ventricles and aqueducts
The Brain
 Ventricles
 Filled with cerebrospinal fluid
 Lined by ependymal cells
 Continuous with one another
The Cerebrum
 Cerebral hemispheres form superior part of brain
 About 80% of brain mass
 3 tissue layers
 Superficial cortex = gray matter
 Internal white matter
 Basal nuclei = islands of gray matter
Anterior
Longitudinal
fissure
Frontal lobe
Cerebral veins
and arteries
covered by
arachnoid
mater
Parietal
lobe
Right cerebral
hemisphere
Occipital
lobe
Left cerebral
hemisphere
(c)
Posterior
Figure 12.6c
The Cerebrum
 Cerebral cortex
 Surface layer of cerebrum
 “Executive Suite”
 Convolutions
Gyri – elevated ridges
 Sulci – shallow grooves
 Fissures – deep grooves, separate larger regions of the brain

The Cerebrum
 Fissures divide cerebral hemispheres into 4 lobes
The Cerebrum
 3 types of functional areas in the cerebral cortex
1.
2.
3.
Motor areas
 Control voluntary movement
Sensory areas
 Conscious awareness of sensation
Association areas
 Integrate diverse information
The Cerebrum
 Functional areas of the cerebral cortex
 Contralateral orientation
 Hemispheres are functionally specialized
 Conscious behavior involves the entire cortex
Cerebral Motor Activity
Motor areas
Central sulcus
Primary motor cortex
Premotor cortex
Frontal eye field
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Sensory areas and related
association areas
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Cerebral Motor Activity
 Primary motor cortex
 Large pyramidal cells of the precentral gyrus
 Long axons  pyramidal (corticospinal) tracts
 Allows conscious control

Precise, skilled, voluntary movements
Posterior
Motor Homunculus
Somatotopy of precentral
gyrus (primary motor cortex)
Motor
Motor map in
precentral gyrus
Anterior
Toes
Jaw
Tongue
Swallowing
Motor homunculi:
upside-down caricatures
representing the
motor innervation
of body regions
Primary motor
cortex
(precentral gyrus)
Figure 12.9
Cerebral Motor Activity
 Premotor cortex
 Anterior to the precentral gyrus
 Controls learned, repetitious or patterned motor skills
 Coordinates simultaneous or sequential actions
 Involved in the planning of movements that depend on sensory
feedback
Cerebral Motor Activity
 Broca’s area
 Anterior to the inferior region of the premotor area
 Present in one hemisphere (usually the left)
 Motor speech area that directs muscles of the tongue

Active as one prepares to speak
Cerebral Motor Activity
 Frontal eye field
 Anterior to the premotor cortex and superior to Broca’s area
 Controls voluntary eye movements
Cerebral Motor Activity
Motor areas
Central sulcus
Primary motor cortex
Premotor cortex
Frontal eye field
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Sensory areas and related
association areas
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Cerebral Vascular Accident (Stroke)
 Types
 Ischemic stroke
 Hemorrhagic stroke
 Result
 Tissue death called an infarct
 Effects are determined by
Where it occurs
 How large the area involved

Stroke
Stroke
Cerebral Sensory Activity
Motor areas
Primary motor cortex
Premotor cortex
Frontal eye field
Central sulcus
Sensory areas & related
association areas
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Cerebral Sensory Activity
 Widely dispersed
 Parietal, temporal & occipital lobes
 Concerned with conscious awareness of sensation
Cerebral Sensory Activity
 Primary somatosensory cortex
 In the postcentral gyri, parietal lobe
 Stimuli from skin, skeletal muscles, and joints
 Capable of spatial discrimination

Identification of body region being stimulated
Posterior
Sensory
Anterior
Sensory map in
postcentral gyrus
Genitals
Primary somatosensory cortex
(postcentral gyrus)
Copyright © 2010 Pearson Education, Inc.
Intraabdominal
Figure 12.9
Cerebral Sensory Activity
 Somatosensory association cortex
 Posterior to the primary somatosensory cortex
 Integrates sensory input from primary somatosensory cortex
 Integrates and analyzes inputs
Temperature, size, texture
 Relationship of parts of objects being felt
 Example: keys in pocket

Cerebral Sensory Activity
 Visual areas
 Primary visual cortex
Occipital lobe
 Receives visual information from the retinas


Visual association area
Surrounds the primary visual cortex
 Uses past visual experiences to interpret visual stimuli
 Example: color, form and movement
 Complex processing involves entire posterior half of the
hemispheres

Cerebral Sensory Activity
 Auditory areas
 Primary auditory cortex
Temporal lobes
 Interprets information from inner ear
 Pitch, loudness and location


Auditory association area
Posterior to the primary auditory cortex
 Stores memories of sounds and permits perception of sounds

Cerebral Sensory Activity
Motor areas
Primary motor cortex
Premotor cortex
Frontal eye field
Central sulcus
Sensory areas and related
association areas
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Association Areas
 Receive inputs from multiple sensory areas
 Send outputs to multiple areas
 Including the premotor cortex
 Function
 Allows us to give meaning to information received, store it as
memory, compare it to previous experience, and decide on
action to take
 Multimodal association areas
Association Activity
 Three areas
 Prefrontal cortex
 Posterior association area (not discussed here)
 Limbic association area
Cerebral Association Activity
Motor areas
Primary motor cortex
Premotor cortex
Frontal eye field
Central sulcus
Sensory areas and related
association areas
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Association Activity
 Prefrontal cortex
 Most complicated cortical region
 Involved with intellect, cognition, recall and personality
 Contains working memory needed for judgment, reasoning
and conscience
 Development depends on feedback from social environment
Association Activity
 Limbic association area
 Part of the limbic system
 Provides emotional impact that helps establish memories
 Connections with prefrontal cortex regulate emotional
expression
Cerebral Association Activity
Motor areas
Primary motor cortex
Premotor cortex
Frontal eye field
Central sulcus
Sensory areas and related
association areas
Broca’s area
(outlined by dashes)
Prefrontal cortex
Working memory
for spatial tasks
Executive area for
task management
Working memory for
object-recall tasks
Solving complex,
multitask problems
(a) Lateral view, left cerebral hemisphere
Primary somatosensory
cortex
Somatic
Somatosensory
sensation
association cortex
Gustatory cortex
(in insula)
Taste
Wernicke’s area
(outlined by dashes)
Primary visual
cortex
Visual
association
area
Auditory
association area
Primary
auditory cortex
Vision
Hearing
Motor association cortex
Primary sensory cortex
Primary motor cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a
Cerebral Lateralization
 Left hemisphere




Math
Logic
Language
Controls right side of body
 Right hemisphere





Visual-spatial skills
Intuition
Emotion
Art and music
Controls left side of body
Cerebral White Matter
 Projection tracts
 Connect cerebrum w/other body locations
 Association tracts
 Interconnect cerebral cortex (same side)
 Commissural tracts
 Connect two hemispheres
White Matter Tracts
Cerebral Gray Matter
 Basal Nuclei
 Association of gray matter deep in cerebral hemispheres
 Contribute to muscle coordination by excitatory innervation

Ex. Parkinson’s
Basal Nuclei
Activity
52
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