Transcript SPHS 4050, Neurological bases, PP 03b

PP 03b-Gross anatomy, in
more detail
Anatomy of the Brain
• Dorsolateral Surface
– Central Sulcus (fissure of
Rolando)
• Separation of primary
motor from sensory
cortex
– Lateral fissure (Sylvian
fissure)
• Separation of frontal
from temporal lobe
– Parieto-occipital sulcus
• Separation of parietal
from occipital lobe
• Borders between lobes
convenient approximations,
and lobes are inter-connected
Frontal lobe
• Largest of the lobes
• Primary motor cortex (Area
4)
– Contralateral
sensorimotor
organization
– Topologic representation
of motor homunculus
here
• Premotor cortex (Area 6)
• Prefrontal cortex (Area 1012)-cognitive brain
– Personality, reasoning,
thinking, executive
decision
• Anterior language cortex
(Area 44/45) “Broca’s area”
Frontal lobe
• Clinical Information
– Prefrontal lobe damage
• Difficulty with planning, problem
solving, thinking, reasoning and
performing executive functions
– Orbital prefrontal damage
• Personality disorders, emotional
disintegration & impulsive social
behaviors
– Medial prefrontal damage
• Problems with attention, motivation
and responsiveness
– Example of Phineas Gage
Parietal Lobe
• Primary somatosensory
cortex (Area 3,1,2)
– Topologic representation of
sensory homunculus here
• Superior parietal lobule
•
(5/7)
– Sensory integration,
visual-spatial and
construction tasks
Inferior parietal lobule
(language [dominant], body
schema, & spatial
orientation [nondominant])
Parietal lobe
• Clinical Information
– Contralateral somatosensory loss
– Perceptual/conceptual
disorders of tactile
recognition
– Impaired constructional
(drawing/designing) skills
– Impaired spatial
orientation
– Visual spatial memory loss
– Tactile agnosia
Summary slide: Primary motor cortex and primary somatosensory cortex
Primary
somatosensory
cortex
(anterior
parietal lobe)
Primary
motor cortex
(posterior
frontal lobe)
Larger size of structure
represents greater
cortical area dedicated
to that structure
Occipital lobe
• Primary Visual Cortex
•
(Area 17, medial
surface, on either side
of calcarine sulcus)
– Visual perception
Secondary Visual
Cortex (Area 18)
– visual recognition
• Clinical: Damage
here associated
with problems with
______________
Temporal Lobe
• Superior, Middle, &
Inferior Gyri
– Primary auditory cortex
• Heschl gyri (Area 41,
42)
– Association language
cortex (Area 22)
• Comprehension of spoken
language
– Hippocampusverbal/nonverbal memory
on medial surface
– Olfaction
Temporal lobe
• Clinical presentation if
damaged
– Deficit in auditory
perceptual and
discriminative skills
– Wernicke’s Aphasia
(dominant temporal
lobe)
– Disorders of nonverbal
memory
• Music (right temporal
lobe)
– Prone to seizures
Ventral Surface
• Frontal, temporal &
occipital lobes
• Major structures
– Orbital cortex
– Olfactory bulb
– Occipito-temporal
gyrus (fusiform)
– Lingual gyrus
– Parahippocampal
gyrus
– Uncus
Clinical Information
Occipito-temporal
region, when damaged,
results in:
Impaired object
recognition, visual
hallucinations, and
failure of facial
recognition
Brain (encephalon)
Cerebrum (telencephalon)
CNS 3-D details (W pp. 9-10 & 97;
2 hemispheres
4 lobes in each hemisphere W&A pp. 25-44 & 48-54)
Deep in each hemisphere:
Limbic system
Basal ganglia
Ventricles
Diencephalon (“between brain”)
Brainstem
Notice the
Midbrain
shaded
Pons
structures and
Medulla
structures
Cerebellum
drawn with
dashed lines.
Spinal cord
Why are they
Cervical
drawn this way?
Thoracic
Lumbar
Of the
Sacral
structures in
Coccygeal
Note: Gradual
the list, which
(not shown)
two are not
transitions b/w the
depicted here?
parts
Here are 3-D views of the “dashed and shaded”
structures in the previous slide’s illustration
3-D views of the
rostral spinal cord, brainstem, diencephalon, and basal ganglia
Anterior view
Posterior view
Lateral view
Basal Ganglia
• Anatomy
– Structures: Caudate nucleus, putamen, globus pallidus, claustrum, &
amygdaloid nucleus
– Associated Structures: Substantia nigra and Subthalamic nucleus
• Function
– Regulation of motor cortical output & muscle tone
– Cognitive functions with multiple projections to prefrontal lobe
• Clinical Information
– Structural damage or reduction/overabundance of specific
neurotransmitters
– Inappropriate movement patterns i.e. tremor, chorea, athetosis, and
myoclonic jerks (hyperkinetic) or difficulty initiating movements
(hypokinetic)
Diencephalon
• Central Core of the Brain
• Structures
– Thalamus
– Hypothalamus
3-D views of the
rostral spinal cord, brainstem, diencephalon, and basal ganglia
Anterior view
Posterior view
Lateral view
Thalamus
• Anatomy
– Above the hypothalamus in
the floor of lateral ventricle
• Functions:
– Transmission of
sensorimotor information to
cortex
– Contribution to cortically
mediated sensorimotor,
speech & language
functions (cortico-thalamocortical connections
Coronal section through deep brain structures, to show relative
positions of thalamus, basal ganglia, and internal capsule
White spaces containing choroid plexus are ventricles
Hypothalamus
• Connections to brain,
brainstem, & spinal cord
by neural & hormonal
efferents, provides
specialized circuitry for:
– Autonomic nervous
system
– Body temperature, blood
volume, food & water
intake, body mass,
reproduction, circadian
rhythms, drives &
emotions