Download The Cerebrum

The Cerebrum
• The Cerebrum
• Is the largest part of the brain
• Controls all conscious thoughts and intellectual
functions
• Processes somatic sensory and motor information
» Voluntary and involuntary
The Cerebrum
• The Cerebrum
• Gray matter found in…
» Superficial layer of neural cortex
» Deeper basal nuclei
• White matter found in…
» Deep to basal cortex
» Around basal nuclei
The Cerebrum
• Structures of the Cerebral Hemispheres
• Lateral and superior surfaces covered in neural
cortex called cerebral cortex
• Outer surface of cerebral cortex covered in a
series of elevated ridges called gyri (JĪ-rī)
» Increase surface area (number of cortical neurons)
• Gryi are separated by shallow depressions called
sulci (SUL-sī)
The Cerebrum
• Structures of the Cerebral Hemispheres
• The cerebral hemipsheres are separated by a
deep longitudinal fissure
» From the fissure, each hemisphere can be divided
into well-defined regions called lobes
• Lobes are named after the overlying bones of the
skull
• QUESTION:
» Can you remember the major bones of the cranium?
The Cerebrum
The Cerebrum
• Structures of the Cerebral Hemispheres
• Extending laterally from the longitudinal fissure is a
deep groove called the central sulcus
» This a major dividing line to separate the different
lobes
• Major Lobes
» Frontal lobe
» Temporal lobe
» Parietal lobe
» Occipital lobe
The Cerebrum
• Review of key features:
• Central sulcus divides:
» Anterior frontal lobe from posterior parietal lobe
• Lateral sulcus divides:
» Frontal lobe from temporal lobe
• Parieto-occipital sulcus divides:
» Parietal lobe from occipital lobe
Copyright © 2010 Pearson Education, Inc.
Copyright © 2010 Pearson Education, Inc.
The Cerebrum
• Review of key features:
• In each lobe, some regions are concerned with
sensory information and motor commands
• Each hemisphere receives sensory information
from, and sends motor commands to, the opposite
side of the body
» Left hemisphere controls right side of body
» Right hemisphere controls left side of body
The Cerebrum
• Motor and Sensory Areas of the Cortex
• Central sulcus separates motor and sensory areas
• Primary Motor Cortex
» Neurons control voluntary motor movements by
controlling somatic motor neurons in the brain stem
and spinal cord
» Located on the frontal lobe (anterior to the central
sulcus)
The Cerebrum
The Cerebrum
• Motor and Sensory Areas of the Cortex
• Central sulcus separates motor and sensory areas
• Primary Sensory Cortex
» Neurons receive somatic sensory information from
touch, pressure, pain, and temperature receptors
» Located on the parietal lobe (posterior to the central
sulcus)
» Consciously aware due to information sent through
brain stem
The Cerebrum
The Cerebrum
• Special Sensory Cortexes
• Smaller regions (cortexes) of the brain process
special sensory information
• Visual Cortex:
» Located on occipital lobe
» Receives visual information
The Cerebrum
The Cerebrum
• Special Sensory Cortexes
• Auditory Cortex:
» Located on temporal lobe
» Receives auditory information
The Cerebrum
The Cerebrum
• Special Sensory Cortexes
• Olfactory Cortex:
» Located on temporal lobe
» Receives information from odor receptors
The Cerebrum
The Cerebrum
• Special Sensory Cortexes
• Gustatory Cortex:
» Located on frontal lobe
» Receives information from taste receptors
The Cerebrum
The Cerebrum
The Cerebrum
• Association Areas
• Regions that interpret incoming data or coordinate a
motor response
• Areas are located within the different “lobes” of the
cerebrum
» Each “lobe” has a different association area
• Two Major Association Areas:
» Sensory Association Area
» Motor Association Area
Sensory Association Areas
• Frontal Lobe
• Prefrontal Association Area
» Reasoning skills
» Coordinates information from other association areas
» Controls some behaviors
Sensory Association Areas
Sensory Association Areas
• Parietal Lobe
• Somatic Sensory Association Area
» Receives and interprets information from skin,
musculoskeletal system, vicera (organs), and taste buds
» Works with primary sensory cortex
Sensory Association Areas
Sensory Association Areas
• Temporal Lobe
• Auditory Association Area
» Receives and interprets information for sound and
hearing from the auditory cortex
Sensory Association Areas
Sensory Association Areas
• Occipital Lobe
• Visual Association Area
» Receives and interprets information for sight from the
visual cortex
Sensory Association Areas
Motor Association Area
• Somatic Motor Association Area
• Responsible for coordinating learned movements
• Usually associated with a voluntary movements
• Also called the premotor cortex
• Located on the frontal lobe
The Cerebrum
• General Interpretive Area
• Also called Wernicke area
• Present in only one hemisphere
» Usually the left hemisphere
• Receives information from all sensory association
areas
• Coordinates access to complex visual and auditory
memories
• Damage Report:
» Can affect the ability to interpret what is read or
heard
The Cerebrum
• Other Integrative Areas
• Speech center (Brocha Area):
» Is associated with general interpretive area
» Coordinates all vocalization functions, including
breathing and vocalization
» Motor commands from this area are adjusted by
auditory association area
• Damage Report:
» Difficulty speaking (mixing words or continuous
speaking)
The Cerebrum
• Other Integrative Areas
• Prefrontal cortex of frontal lobe:
» Integrates information from sensory association
areas
» Performs abstract intellectual activities
» Feelings of frustration, tension and anxiety are
generated here
• Damage Report:
» Difficulty estimating time relationships between
events
Hemispheric Lateralization
• Hemispheric Lateralization
• Functional differences between left and right
hemispheres
• Each cerebral hemisphere performs certain
functions that are not ordinarily performed by the
opposite hemisphere
• Hemispheres are connected by the corpus
callosum
Hemispheric Lateralization
• Corpus Callosum
• Region of white matter that lies beneath the
cerebral cortex
• Axons of different lengths interconnect within a
single hemisphere
Hemispheric Lateralization
• The Left Hemisphere
• In most people, the left brain (dominant hemisphere)
controls:
» Reading, writing, and math
» Decision making
» Speech and language
» Analytical tasks and logical reasoning
• Location of premotor cortex involved with hand
movements
» Control of right-handedness or left-handedness
Hemispheric Lateralization
Hemispheric Lateralization
• The Right Hemisphere
• Right cerebral hemisphere relates to:
» Analyzes sensory information
» Interpretative ability based on senses (touch, smell,
sight, taste, hearing)
» Recognition (faces, voice inflections)
Hemispheric Lateralization
The Cerebrum
• The Basal Nuclei
• Also called cerebral nuclei
• Are masses of gray matter
• Are embedded in white matter of cerebrum
• Direct subconscious activities
The Cerebrum
• Functions of Basal Nuclei
• Involved with:
» The subconscious control of skeletal muscle tone
» The coordination of learned movement patterns
(walking, lifting)
• Example  walking
» Basal nuclei controls cycles of arm and thigh
movements that occur while walking
The Basal Nuclei
The Basal Nuclei
The Limbic System
• The Limbic System
• Is a functional grouping that:
» Establishes emotional states
» Links conscious functions of cerebral cortex with
autonomic functions of brain stem
» Facilitates memory
storage and retrieval
The Limbic System
• Functions of the Limbic System
• Regulation of heart rate during “fight or flight”
response
• Linking of memories to emotions
• Storage of long-term memories
• Control of emotional states
• Reflex movements that can be consciously
activated
The Limbic System
The Diencephalon
• Functions of the Diencephalon
• Made up of the thalamus, epithalamus, and
hypothalamus
• Integrates conscious and unconscious sensory
information and motor commands
The Diencephalon
• Functions of the Epithalamus
• Contains the pineal gland
» Secretes hormone melatonin
» Helps to regulate day-night cycles
• Functions of the Thalamus
• Final relay point for all ascending sensory information
• Acts as a filter to pass on ONLY the most important
sensory information
• Coordinates voluntary and involuntary motor
commands
The Diencephalon
• Functions of the Hypothalamus
• Subconscious control of skeletal muscle contractions
• Coordinates activities between nervous and endocrine
systems
• Produces feelings of “hunger” and “thirst”
• Regulates normal body temperature
• Coordinates cycles of activity
The Diencephalon and Brain Stem
The Midbrain
• Functions of the Midbrain
• Helps to process visual and auditory sensations
» Causes you to flinch when you hear a loud noise
• Maintenance of muscle tone and body posture
• Integrates information from cerebrum and
cerebellum
The Diencephalon and Brain Stem
The Pons
• Functions of the Pons
• Links cerebellum with midbrain, dienchephalon,
cerebrum and spinal cord
• Involuntary control of respiration pace and depth
The Diencephalon and Brain Stem
The Medulla Oblongata
• Function of the Medulla Oblongata
• Allows brain and spinal cord to communicate
• Coordinates complex autonomic reflexes
• Controls visceral functions
• Nuclei in the medulla:
» Autonomic nuclei: control visceral activities
» Sensory and motor nuclei: of cranial nerves
» Relay stations: along sensory and motor pathways
The Diencephalon and Brain Stem