Exam 1

• Moved to the 31 of January

Thebrainmcgill

• 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

• 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 bodiesNerve 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– 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

• 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

• 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 movementDisease 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– 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.