Download ANPS 019 Beneyto 11-06

Cerebrum
Parietal
Frontal
Occipita
l
Temporal
November 6, 2013
Chapter 13: 496 - 505
Dr. Diane M. Jaworski
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The Cerebrum
• Is the largest part of the brain
• Controls all conscious thoughts and
intellectual functions
• Processes somatic and visceral
sensory and motor information
2
Functional Principles of the
Cerebrum
• Each cerebral hemisphere receives sensory
information from, and sends motor commands to, the
opposite side of the body
• Although similar in structure, the 2 hemispheres have
different functions (e.g., language on left, face
recognition on right)
• Specific regions of the cerebral cortex have specific
functions, but there is overlap in function
• Primary motor and sensory areas are organized into
topographic maps representing specific body
regions
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Hemispheric
Lateralization
• “brain sided-ness” does not always
correspond to “handed-ness”
• Right side - “Creative”:
- Musical and artistic awareness
- Spatial and pattern perception
- Face recognition
- Emotional part of speech
• Left side - “Analytical”:
- Spoken and written language
- Numerical and scientific skills
- Reasoning
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© McKinley et al. A & P 2013
The Corpus Callosum is made of the axons (white
matter) of cortical neurons communicating between the
left and right cerebral hemispheres
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© McKinley et al. A & P 2013
Everyone has the same pattern of gyri
and sulci on their cerebral cortex
Different gyri deal with different types of
information
Sulcus
shallow depression
(plural: sulci)
Gyrus
elevated ridge
(plural: gyri)
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© McKinley et al. A & P 2013
Different areas of the cortex perform
different functions
“Primary” areas : neurons receive sensory information
or directly send out motor instructions
“Association” areas : neurons make sense of sensory information
or plan motor activities (muscle movements)
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© McKinley et al. A & P 2013
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© McKinley et al. A & P 2013
Frontal Lobe:
Motor and Limbic Functions
Premotor Cortex
Primary
Motor Cortex
Prefrontal
Cortex
Broca’s Area
Motor speech
Central sulcus
Separates frontal and parietal lobes
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Frontal Lobe:
Primary Motor Cortex
Central sulcus
12
© McKinley et al. A & P 2013
Frontal Lobe:
Primary Motor Cortex
• Primary Motor Cortex = Precental gyrus
- Directs voluntary muscle movement
- Contains a map of all skeletal muscles
- Pyramidal neurons in this gyrus project via the internal
capsule to synapse in the brainstem or spinal cord;
they talk to the neurons that contact the muscles
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(they do NOT directly synapse on the muscles!!)
The internal capsule contains Pyramidal neuron axons
leaving the cortex (motor info) AND the axons of
neurons bringing sensory info into the cortex
Internal
Capsule
© McKinley et al. A & P 2013
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Neurons in the primary motor cortex are arranged
according to the muscles they control
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Frontal Lobe:
Premotor Cortex
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Frontal Lobe:
Premotor
Cortex
* learned motor activities
planning of motor activities
• Directs neurons in the primary motor cortex; therefore,
less discrete topographic map
• Contains two specialized regions:
- Frontal eye fields
- Broca’s speech area
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Frontal Lobe:
Frontal Eye Fields
The purpose of this region is to keep the eyes directed forward.
The right frontal eye field forces both eyes to the left while the left
frontal eye field forces both eyes to the right. In a unilateral lesion,
both eyes will deviate TOWARDS the side of the lesion.
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Frontal Lobe:
Broca’s Speech Area
Broca's Aphasia
http://www.youtube.com/watch?v=f2IiMEbMnPM&feature=related
• Primarily located in left hemisphere - produces speech
•
Expressive (motor, non-fluent) aphasia
- anomia (inability to name objects)
• Patient aware of deficit
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Frontal Lobe:
Prefrontal Cortex
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Frontal Lobe:
Prefrontal Cortex
• Largest part of the frontal lobe
• Many connections to other areas
• Vague limbic functions (e.g., personality)
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© McKinley et al. A & P 2013
Parietal Lobe: Somatosensation
(the sense of touch, awareness of body)
Primary Somatosensory Cortex
Somatosensory
Association Cortex
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Parietal Lobe:
Primary Somatosensory Cortex
Central sulcus
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© McKinley et al. A & P 2013
Parietal Lobe:
Primary Somatosensory Cortex
• Primary Somatosensory Cortex = Postcental gyrus
• Receives somatic sensory information from skin
receptors, joints and muscles:
– Touch, pressure, vibration
– Pain and temperature
– Taste
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Neurons in the primary somatosensory cortex
are arranged according to the body region they
receive information from
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The maps in the primary motor and somatosensory
cortices are the same,
just the amount of cortex devoted differs!
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Parietal Lobe:
Somatosensory Association
Cortex
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Parietal Lobe :
Somatosensory Association Cortex
• Interpretation of sensations
– Shape and texture of object
– Orientation of object (where an object is in space)
– Relationship of body parts
stroke to right parietal association cortex results in a fascinating
syndrome in which the patient disregards the left side of their
body = syndrome of hemineglect
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Syndrome of Hemineglect
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© McKinley et al. A & P 2013
Temporal Lobe:
Hearing, Limbic Function, Visual Association
Primary
Auditory
Cortex
Wernicke’s
Speech
Lateral fissure
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Area
Separates frontal, parietal & temporal lobes
Temporal Lobe
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Temporal Lobe:
Primary Auditory Cortex
• Primary Auditory Cortex
– Receives sound information, sorts by frequency
(tonotopic map)
– Pitch, rhythm
© Bear et al. Neuroscience 1996
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Temporal Lobe:
Wernicke’s
Speech Area
Wernicke’s Area
• Primarily located in left hemisphere
• Speech comprehension
• Receptive (sensory, fluent) aphasia
- language comprehension affected
- nonsensical speech, but patient unaware of deficit
- anomia, impaired repetition, non-fluent reading
- apraxia (inability to execute motor activity based
on verbal command)
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Temporal Lobe:
Auditory Association Cortex
Wernicke’s Speech Area
Wernicke's Aphasia
http://www.youtube.com/watch?v=aVhYN7NTIKU
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Temporal Lobe:
Limbic System
(will be discussed later in the course)
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© McKinley et al. A & P 2013
Occipital Lobe: Vision
Visual
Association
Cortex
Primary Visual
Cortex
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Occipital Lobe:
Primary Visual Cortex
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© McKinley et al. A & P 2013
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© McKinley et al. A & P 2013
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© McKinley et al. A & P 2013