Download Lecture 3

Exam 1
• Moved to the 31 of January
Thebrainmcgill
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Simple to complex
Neurological level
Intermediate level
Midsagittal view
Slides 5, 6, 8, 9
• Could be on test
• So be ready to label structures and their
functions
Brainstem Cerebellum & Deep
Structures
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Brainstem: Midbrain, Pons, Medulla
Thalamus
Cerebellum
Basal Ganglia
Limbic System
Nuclei
Collection of neuronal somas in
the deeper brain structures
Nerves
Contain the axons from the neuron cell
bodies aka soma
Nuclei is a collection of neuronal cell bodies
Nerve is a collection (fascicle) of neuronal axons
Brainstem
• Primitive Part of Brain
– Midbrain aka mesencephalon
– Pons metencephalon together with cerebellum
– Medulla Oblongata myencephalon
MIDBRAIN
• Functions in visual and auditory orientation
reflexes, maintaining posture and voluntary
movements of body and face
• Contains nuclei for cranial nerves 3,
oculomotor; 4, trochlear; 6, abducens
• a thoroughfare for axons entering and
leaving brain.
PONS
• Central portion of brainstem
• Regulates respiration, thoroughfare for motor and
sensory fibers, controls movement of face & jaw
muscles, eye movement & sensation to face
• Contains nuclei for cranial nerves: 5, trigem; 7,
facial
• Trigeminal, abducens, facial, vestibulocochlear
nerves run through it
Medulla Oblongata
• Caudal portion of brainstem, leads to spinal
cord
• Contains nuclei for CN 9-12 involved in
speech (tongue & vocal cords), swallowing,
move neck & shoulder muscles, salivation,
taste
• Thoroughfare for afferent & efferent fibers
Motor Modulation Systems
• Cerebellum
• Basal Ganglia
CEREBELLUM
• derived from hindbrain but not part of brain
stem.
• connected to pons and medulla by
cerebellar peduncles that are made up of
axons entering and leaving the cerebellum
• 4th ventricle separates it from brain stem.
Cerebellum
• Major functions
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Coordinate muscle activity
Posture
Equilibrium
Spatial Reasoning
Function
• Motor control for muscle coordination and in
planning complicated movements
• Cognitive tasks involved in learning and memory
of motor task.
• Lesions to humans or animals shows that distinct
areas of the cb are necessary for spatial reasoning,
keeping muscle tone during voluntary movement
or reflexes
• people can't walk in a coordinated smooth manner
after cb lesion ie they appear to walk as if drunk
Cerebellar Lobes
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Rostral or anterior
Caudal or posterior
Vermis
Flocculonodular
• Folia is a term used from gyri in cerebellar
cortex that are smaller than in cerebral
cortex
Deep Cerebellar Nuclei
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Emboliform
Dentate
Globose
Fastigial
• Are main output neurons from cerebellum
Deep Brain Nuclei
• Diencephalon: processing sensory & motor
information & endocrine role
• Basal Ganglia-Striatum: 3 forebrain nuclei
involved in motor control
• Limbic System: Involved in regulating emotion,
motivation & homeostasis
DIENCEPHALON
• Anterior to midbrain and forms the walls of
the third ventricle.
• Consists of two parts, the thalamus and
hypothalamus
– Thalamus: processes sensory info & relays
motor info
– Hypothalamus: part of limbic system, controls
pituitary
THALAMUS
• Subdividing into 6 nuclei
• Relay station for afferent incoming sensory
information on the way to the appropriate
cortical regions.
• Several nuclei in the thalamus receive
visual information from the optic nerves
• Other nuclei receive auditory information
and motor information.
HYPOTHALAMUS
• involved in maintaining homeostasis, controls
body temperature, blood pressure, salt and water
levels
• initiates and supresses eating, drinking
• Activates and inhibits pituitary gland, a
neuroendocrine organ
• regulates autonomic function such as blood
pressure & temperature
• involved in emotional responses such as changes
in blood pressure/heart rate/respiration, blushing
and sweating
BASAL GANGLIA
• Nuclei surrounding thalamus with common
function
– 3 components
• putamen, globus pallidus, caudate nucleus
aka striatum
• Substantia nigra
• Subthalamic nuclei
Deep Brain Nuclei involved in starting and stopping movement
Disease to substantia nigra causes parkinson’s disease
Function
• Function in initiation and planning of
voluntary movement and tone of antigravity
muscles.
Limbic System
• Limbic means “border/edge”
• Function to
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Regulate visceral motor function
Emotions , fear irritability depression aggresion
Memory
Olfaction—food aversions
Stop Here
Slides 40-43 have details that will not
be included in the test. They will be
covered during the 2nd half of the
course.