Transcript Neuroanatomy Handout #3: Brain Structures The Cerebral Cortex

Chapter 3
Anatomy and Research Methods
Module 3.1:
• Structure of the
Vertebrate Nervous
System
Module 3.2:
• The Cerebral Cortex
Module 3.3:
• Research Methods
Correlating Brain and Behavior
Phrenology (1800s)
Franz Joseph Gall (1758–1828)
Trephining
Frontal Lobe Brain Damage
Phineas Gage, 1848
Louis Victor Leborgne, “Tan,” 1861
Frontal Lobe Brain Damage
Lobotomy (1930s-1950s)
Frontal Lobe Brain Damage
Travis Bogumill, 1998
Jarod Behee, 2007
Neurosurgery and Topographical Mapping
Wilder Penfield:
Mapping the Cortex
(1947)
Wilder Penfield video clip (3m):
https://www.youtube.com/watch?v=6
8MiW2KK1us
Neurosurgery
In this video clip, a woman
is having surgery to remove
a tumor near Broca’s area
(4m):
https://www.youtube.com/
watch?v=KpkH25XVpFU
Modern Techniques for Studying the Brain:
Neurosurgical Techniques
• Lesion
– damage to a brain area
(electrical or chemical)
• Ablation
– removal of brain area
• Stereotaxic instrument
– a device that allows for precise
neurosurgical procedures
• Sham lesion
– performing identical procedures
except for damaging the brain
– produced by an experimenter in
a control subject
Modern Techniques for Studying the Brain
• Positron-emission tomography (PET Scan)
– records emission of radioactivity from injected
radioactive chemicals to produce a highresolution image
– shows where activity occurs in the brain
Modern Techniques for Studying the Brain
Recording brain activity
involves using a variety
of noninvasive methods
including:
• Magnetic
Resonance
Imaging (MRI)
– involves the
application of a
powerful magnetic
field to image the
brain
– good for viewing soft
tissue
Modern Techniques for Studying the Brain
• Electroencephalography
(EEG)
– Records electrical activity
produced by cortical regions
of the brain
– Produces a record of
brainwaves.
– Widely used for sleep
research
Divisions of the Vertebrate Nervous System
Neuroanatomy:
• anatomy of the
nervous system
• the study of the
various parts of
the nervous
system and their
respective
function(s)
• consists of many
substructures,
each comprised
of many neurons
Divisions of the Vertebrate Nervous System
The Nervous System is
comprised of two major
subsystems:
1. The Central Nervous
System (CNS)—
brain and spinal cord
2. The Peripheral
Nervous System
(PNS)
Central Nervous System
 Brain
 Comprised of 100 billion
neurons
 “Command Central” of
the nervous system
 Spinal cord
 the part of the CNS
found within the spinal
column
 communicates with the
sense organs and
muscles below the level
of the head
 Functions according to
the Bell-Magendie law
Central Nervous System
The Bell-Magendie law states the
entering dorsal roots carry sensory
information and the exiting ventral
roots carry motor information.
Peripheral Nervous System
•
The Peripheral
Nervous
System (PNS)
sends
information to
the CNS and
is comprised
of the:
1. Somatic
Nervous
System
2. Autonomic
Nervous
System
Peripheral Nervous System
• The Somatic Nervous
System consists of
nerves that:
– Convey sensory
information to the
CNS.
– Transmit messages
for motor movement
from the CNS to the
body.
– Control skeletal
muscles
Peripheral Nervous System
•
The autonomic
nervous system
regulates behaviors
of internal glands
and organs
• Divided into 2
subsystems:
1. Sympathetic
Nervous System
2. Parasympathetic
Nervous System
Peripheral Nervous System
• Sympathetic nervous
system: a network of
nerves that prepares
the organs for
rigorous activity by
increasing:
– heart rate
– blood pressure
– respiration
– etc.
• Responsible for “fight
or flight” response
Peripheral Nervous System
• The parasympathetic
nervous system
facilitates vegetative,
nonemergency
responses by the
organs.
– decreases functions
increased by the
sympathetic nervous
system.
– dominant during our
relaxed states.
Anatomical Terms:
Views
Terms used to describe
views when referring to
the nervous system
include:
Ventral: toward the stomach
Dorsal: toward the back
Ventral
Dorsal
Anatomical Terms:
Views
Terms used to describe views
when referring to the
nervous system include:
Anterior: toward the front end
Posterior: toward the back end
Lateral: toward the side
anterior
posterior
lateral
Anatomical Terms:
Location/direction
Terms used to describe
location/direction in the
nervous system include:
Superior: above another part
Inferior: below another part
Anatomical Terms:
Location/Direction
Terms used to describe
location/direction in the
nervous system include:
Lateral: toward the side
Medial: toward the midline
Anatomical Terms:
Location/Direction
Terms used to describe
location/direction in the
nervous system include:
Ipsilateral: on same side
Contralateral: on opposite side
Anatomical Terms:
Planes/Sections/Cuts
Terms referring to
planes/sections/cuts:
Horizontal: shows brain
structures as seen from
the top
Sagittal: shows brain
structures as seen from
the side
Coronal: shows brain
structures as seen from
the front
Anatomical Terms:
Specialized Parts
Terms referring to
specialized parts of the
nervous system:
Gray matter: cell bodies
and dendrites
White matter: axons,
mostly myelinated
Anatomical Terms:
Specialized Parts
Terms referring to
specialized parts of the
nervous system:
Tract/projection: set of
axons in the CNS
Nerve: set of axons in the
PNS
Nucleus: cluster of
neuron cell bodies
within CNS
Ganglion: cluster of
neuron cell bodies in
the PNS
Anatomical Terms:
Specialized Parts
Terms referring to
specialized parts of the
nervous system:
Gyrus (pl: gyri): mound on
surface of brain
Sulcus (pl: sulci):
fold/groove separating
one gyrus from another
Fissure: long, deep sulcus
Neuroanatomy Handout #3: Brain Structures
•
The brain can be divided into three major
divisions:
1. Hindbrain.
2. Midbrain.
3. Forebrain.
Neuroanatomy Handout #3: Brain Structures
• The Hindbrain
consists of the:
– Medulla
– Pons
– Cerebellum
• Located at the
posterior portion of
the brain
Neuroanatomy Handout #3: Brain Structures
• The medulla (A):
– Located just above the
spinal cord
– Responsible for vital
reflexes such as
breathing, heart rate,
vomiting, salivation,
coughing and
sneezing.
• Cranial nerves allow the
medulla to control
sensations from the head,
muscle movements in the
head, and many
parasympathetic outputs
to the organs.
Neuroanatomy Handout #3: Brain Structures
• Pons (B)
– lies on each side of
the medulla (ventral
and anterior).
– along with the
medulla, contains the
reticular formation and
raphe system, which
work together to
increase arousal and
readiness of other
parts of the brain
Neuroanatomy Handout #3: Brain Structures
• Cerebellum (C):
– located posterior to the
brainstem with many
deep folds
– helps regulate motor
movement, balance and
coordination
– also important for
shifting attention
between auditory and
visual stimuli
Neuroanatomy Handout #3: Brain Structures
• The midbrain (D) is
comprised of the following
structures:
– Superior colliculus:
helps process visual
info
– Inferior colliculus: helps
process auditory
information
– Substantia nigra –
involved in movement
Neuroanatomy Handout #3: Brain Structures
• Brain stem consists
of the:
– Medulla
– Pons
– Midbrain
– Some forebrain
structures
Neuroanatomy Handout #3: Brain Structures
• Forebrain: most
prominent part of
the mammalian
brain, consisting of:
– the outer cortex
(“cerebral cortex”)
– subcortical
regions
Neuroanatomy Handout #3: Brain Structures
• The limbic system is
associated with
motivation, emotion,
drives and aggression,
and includes:
– Olfactory bulb
– Hypothalamus
– Hippocampus
– Amygdala
• Olfactory bulbs send
info about smell to
cortex
Neuroanatomy Handout #3: Brain Structures
• Hypothalamus (F)
– Conveys messages to the
pituitary gland to trigger the
release of hormones
– Regulates autonomic nervous
system
– Involved in emotions and drives
vital to survival:
• Eating
• Drinking
• Sexual behavior
• Fear
• Feeling rewarded
Neuroanatomy Handout #3: Brain Structures
• Pituitary gland (G)hormone producing
gland found at the base
of the hypothalamus.
• AKA: “Master Gland”
Neuroanatomy Handout #3: Brain Structures
• Hippocampus is a large
structure of the limbic
system critical for
storing certain types of
memory.
• H.M., 1953
Neuroanatomy Handout #3: Brain Structures
• Amygdala: almond-shaped
structure important for:
– initial emotional response to
stimuli
– directing motivated
behavior at an appropriate
target
Neuroanatomy Handout #3: Brain Structures
• Forebrain structures
include:
– Thalamus (E) - relay
station for the sense
organs and main
source of input to the
cortex.
Neuroanatomy Handout #3: Brain Structures
• Basal Ganglia comprised of the
caudate nucleus, the
putamen and the
globus pallidus.
– Associated with
planning of motor
movement, and
aspects of memory
and emotional
expression .
Neuroanatomy Handout #3: Brain Structures
• Nucleus basalis:
– receives input
from the
hypothalamus
and basal
ganglia
– key part of the
brain’s system
for arousal,
wakefulness,
and attention
Neuroanatomy Handout #3: Brain Structures
• The ventricles are four fluid-filled cavities
within the brain containing cerebrospinal fluid.
The central canal is a fluid-filled channel in
the center of the spinal cord.
Neuroanatomy Handout #3: Brain Structures
• Cerebrospinal fluid (CSF)
is a clear fluid similar to
blood plasma found in the
brain and spinal cord:
– Provides “cushioning”
for the brain
– Reservoir of hormones
and nutrition for the
brain and spinal cord
– Choroid plexus: groups
of cells in the 4
ventricles that
continually manufacture
CSF
Neuroanatomy Handout #3: Brain Structures
• Meninges: thin
membranes surrounding
brain and spinal cord
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• The cerebral cortex is the most prominent part
of the mammalian brain and consists of the
cellular layers on the outer surface of the brain.
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• The four lobes of the cerebral cortex:
•
•
•
•
Occipital lobe
Parietal lobe
Temporal lobe
Frontal lobe
2 hemispheres
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• The Frontal lobe (H):
– involved in attention,
planning, decision-making,
etc.
– contains Broca’s area
(principal speech area) (H1)
– contains Precentral gyrus
(primary motor cortex) (H2),
responsible for control of
fine motor movement
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• Parietal lobe (I) :
– involved in body sensations
– contains postcentral gyrus
(I1) (primary sensory area), a
main target for touch
sensations
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• Temporal Lobe (J):
– involved in hearing
– also responsible for some
emotional and
motivational behaviors
– contains primary auditory
cortex (J1): Target for
auditory information and
essential for processing
spoken language
Neuroanatomy Handout #3: Brain Structures
The Cerebral Cortex
• Occipital lobe (K):
– Highly responsible for
visual processing
– contains striate cortex
or primary visual area
(K1)
– damage can result in
cortical blindness
Neuroanatomy Handout #3: Brain Structures
Central sulcus (L)
Longitudinal fissure (M)
Lateral fissure (N)
Neuroanatomy Handout #3: Brain Structures
• Corpus callosum
(O): large bundle of
axons joining the 2
hemispheres
• Anterior
commissure (P):
small bundle of
axons joining the 2
hemispheres
The Cerebral Cortex
• The binding problem
refers to the question
of how the visual,
auditory, and other
areas of the brain
produce a perception
of a single object.
– All areas of the
brain
communicate with
each other