MCB 244 UIUC Final Exam Part II

Lobes of the Cerebrum

(named from cranial bones): Frontal, Parietal, Temporal, Occipital, Insular (not visible at the surface)

Frontal Lobe

Anterior

-Posterior border is deep central sulcus

-Lateral sulcus separates inferior frontal lobe from temporal lobe

Functions of the Frontal Lobe

Motor Control, concentration, verbal communication, decision making, planning, personality (think executive functioning)

Function of Precentral Gyrus

controls voluntary movement

Parietal Lobe

Supero-posterior

-Anterior border is central sulcus; postcentral gyrus is a ridge just posterior to central sulcus

-Posterior border is parieto-occipital sulcus

-Lateral border is lateral sulcus

Functions of the Parietal Lobe

General sensory functions (evaluating shape and texture of objects)

Where is precentral vs postcentral gyrus found?

Precentral Gyrus: Frontal Lobe, deep within central sulcus

Postcentral Gyrus: Parietal Lobe just posterior to central sulcus

Temporal Lobe

Inferior to lateral sulcus

Functions of the Temporal Lobe

hearing & smell

Occipital Lobe

Posterior part of Cerebrum

Functions of Occipital Lobe

Vision & visual memories

Insula Lobe

Deep to lateral sulcus

-Small lobe that can be observed by pulling away temporal lobe

Functions of the Insula Lobe

Memory & Sense of Taste

Where are motor areas found

Within the Frontal Lobes

Primary Motor Cortex (Somatic motor area)

Located in precentral gyrus

-controls skeletal muscle activity on opposite side of body (contralaterally)

Motor Homunculus

Distorted proportions of body -reflect amount of cortex dedicated to each part

Broca Area Synonym

Motor Speech Area

Broca Area (Motor Speech Area)

location: in inferolateral portion of left frontal lobe

Function: controls movements for localization

What happens if the Broca Area is injured?

Can form ideas but has difficulty expressing them.

Frontal Eye Field

Location: on superior surface of middle frontal gyrus

Function: regulates eye movements needed for reading/ binocular vision

Premotor Cortex Synonym

Somatic Motor Association Area

Somatic Motor Association Area (Premotor Cortex)

Location: Anterior to prefrontal cortex

Functions: learning coordinated, skilled activities

What would happen if the premotor cortex is damaged?

Apraxia (unable to button up a shirt)

Altered body orientation

Impaired motor planning

Primary Somatosensory Cortex Location

postcentral gyrus of parietal lobes

Function of Primary Somatosensory Cortex

Receives somatic sensory information from proprioceptors, touch, pressure, pain, temperature receptors

Sensory Homunculus

A map that used to show distorted proportions reflected by the amount of sensory information collected from that region.

What regions are most prominent in the sensory homunculus?

Lips, Fingers, Genital Regions

Somatosensory Association Area Location

immediately posterior to postcentral gyrus (in parietal lobe)

Somatosensory Association Area Function

integrates touch information allowing us to identify objects by feel

Primary Visual Cortex Location & Function

Location: Occipital Lobe

Functions:

-received, processes, stores visual information

Visual Association Area Location & Function

Location: Surrounds Primary Visual Cortex

Functions:

-Integrates and interprets color, form, to allow identification/recognition of things

What would be the result if the primary visual cortex or visual association area were injured?

Unable to remember/ process faces, dogs, etc.

Primary Auditory Cortex Location & Function

Location: Temporal Lobe

Functions:

Receives, processes, stores auditory information

Auditory Association Area Location & Function

Location: temporal lobe

Function:

Integrates and interprets sounds

Primary Olfactory Cortex Location & Function

Location: temporal lobe

Function: receives, processes, stores odor information

Primary Gustatory Cortex Location & Function

Location: within the Insula

Function: receives, processes, stores taste information

Main thing to remember about Cortex:

Receives, Processes, and Stores information related to their lobe

Main thing to remember about association areas:

Integrates & Interprets information related to their lobe

Functional Brain Regions Types & Function

Integrates information from multiple association areas

-Prefrontal Cortex

-Wernicke Area

Prefrontal Cortex Location & Function

Location: Rostral to premotor cortex (In frontal Lobe)

Function: complex thought, judgement, personality, planning, deciding, still developing in adolescence

Wernicke Area Location & Function

Location: typically left hemisphere

Function: involved in language comprehension

What would happen if Wernicke Area was damaged?

May speak nonsense, difficulty understanding speech from others

Damage to Wernicke Vs Broca Areas

Wernicke: Left Temporal Lobe

- Normal fluency & Speed

- Errors in sound & Word

selection

- Comprehension of language hurt

Broca: Left Frontal Lobe

-Impaired speech production may be slow, take great effort

-comprehension intact

Central White Matter Location & Composition

Deep to Gray Cerebral Cortex

Composed of myelinated axons grouped into tracts

Association Tracts Functions & Types

Function: Connect regions of cerebral cortex within same hemisphere

Types:

Arcuate (Bowed) Fibers: Short

Longitudinal Fasciculi: Long connect different lobes

Commissural Tracts

Connects regions in different hemispheres

Commissures locations

Corpus Callosum (C-Shaped), anterior, posterior commissures

Refer to Lec III - slide 49

Projections Tracts Function

Link Cerebral Cortex to inferior brain regions and spinal cord (example: corticospinal tracts carry signal from cerebral cortex to spinal cord)

Function of Internal Capsule

projection tract that passes between thalamus and cerebral nuclei

One type of anatomical asymmetry

Petalias

Petalias

protrusion of a love on one side compared to other side

Right Vs Left Handed individuals

Right handed: Petalias on Right frontal lobe and left occipital lobe

Left Handed: Petalias on Left Frontal Lobe, and right occipital lobe

Categorical Hemisphere is which side & its functions?

Left Hemisphere

Functions: Language abilities, categorization and analysis, Wernicke & Motor Speech Area

Representational Hemisphere is which side & its function?

Right Hemisphere

Functions: visuospatial relationships, imagination, comparison of senses

Function of Corpus Callosum

helps the two hemispheres to communicate with each other and other commissures

When does Lateralization develop?

early childhood - prior to 5-6 years

Lateralization differences between the sexes?

Women- more connections due to thicker posterior corpus callosum

Men - more functional loss when one is damaged

Which hemisphere is almost always categorical and speech dominant in either right or left handed individuals?

Right Handed: Left hemisphere

Left Handed: either

Cerebral (Basal) Nuclei Found in where & its functions:

Found in: gray matter deep in cerebrum

Functions: Help regulate motor output; diseases of these nuclei associated with involuntary movements

Caudate Nucleus Shape & Function

enlarged head and slender tail paralleling lateral ventricle;

Function: helps produce pattern and rhythm of walking movements

Lentiform Nucleus

rounded mass between insula and diencephalon;

composed of:

-putamen

-globus pallidus

Function of the Putamen (Shell)

helps control movements at subconscious level

Function of the Globus Pallidas (Pale Ball)

influences thalamus to adjust muscle tone

Claustrum ('barrier') Location and Function

Location: thin sliver of gray matter immediately internal to insula cortex

Function: extensive connections to cerebral areas suggest involvement in consciousness

Function of the Amygdaloid body

expanded region at tail of caudate nucleus; functions in mood, emotions

Appearance of Corpus striatum

striated or striped appearance of the internal capsule

Basal nuclei Vs Basal ganglia

Nuclei: denotes cell bodies WITHIN the CNS

Ganglia denotes cell bodies EXTERNAL to the CNS

Headache Cause

Dilated blood vessels in skull or muscle contraction

Migraines Headaches

Unilateral, severe, recurring

Cerebral Palsy Cause & Outcome

Cause: damage to infant brain before, during, or right after birth

Outcome: Impairment of skeletal muscle, sometimes mental retardation

Huntington Disease affects what part?

Cerebral Nuclei

Huntington Disease Characteristics

Rapid, Jerky, involuntary movements, intellectual deterioration

-Fatal within 10 to 20 years after onset

Parkinson Disease characteristics, cause, and outcome?

Characteristics: Stiff Posture, Slow Voluntary movements, resting tremor

Cause: Decreased dopamine production in substantia nigra

Affects: muscle movement and balance

Diencephalon Includes what?

epithalamus, thalamus, and hypothalamus

Nickname for Diencephalon

"In-Between Brain"

Epithalamus forms what, covers which ventricle, and includes what other parts?

Forms: posterior part of roof or diencephalon and covers third ventricle.

Includes:

-Pineal Gland

-Habenular Nuclei

Pineal Gland Function

Endocrine Gland that Secretes melatonin, helps regulate day-night cycles, circadian rhythm

Habenular Nuclei Function

Help relay signals from limbic system to midbrain; involved in visceral and emotional responses to odor

Thalamus Characteristics

Oval Masses of gray matter on lateral sides of third ventricle.

Receives signals from all conscious senses except olfaction; relays some signals to appropriate part of cortex and filters out other signals distracting from subject of attention (Background Noise in Crowded room)

Interthalamic Adhesion Function & Composition

Midline mass of gray matter connecting left and right thalamus

Composed of about a dozen thalamic nuclei.

Thalamic Nuclei

Axons from a given nucleus project to a particular region of cortex

Hypothalamus Nickname

CEO of the ANS and endocrine system

Hypothalamus location

Anteroinferior region of the diencephalon

Name of the Stalk of pituitary that extends from hypothalamus

Infundibulum

Functions of the Hypothalamus

-Controls ANS

-Controls Endocrine system

-Regulates Body Temp

-Regulates hunger & Thirst

-Controls Sleep-Wake rhythms

-Controls Emotional Behavior & Responses

Think COMFORT for last four.

Brainstem Composition

-Connects cerebrum, diencephalon, and cerebellum to spinal cord

-Contains ascending and descending tracts

-Contains autonomic nuclei, nuclei of cranial nerves, and reflex centers

Parts of the Brainstem

-Midbrain (Top)

-Pons

-Medulla Oblongata (Bottom)

Parts of the Midbrain

-Cerebral Peduncles

-Superior Cerebellar Peduncles

-Medial Lemniscus

-Substantia Nigra

-Tegmentum

-Cerebral Aqueduct

-Tectum

Midbrain Houses what Nuclei?

CN III (oculomotor)

IV (trochlear)

Cerebral Peduncles Functions

motor tracts (pyramidal system) on anterolateral surface of midbrain

-carry voluntary motor commands from primary motor cortex

Superior Cerebellar Peduncles connects what to what?

connects cerebellum to midbrain

Medial Lemniscus composition

bands of ascending, myelinated axons running through brainstem

Substantia Nigra Appearance & Function

cluster of cells with black appearance due to melanin

-houses neurons producing dopamine (involved in movement, emotions, pleasure and pain response)

-its degeneration causes Parkinson disease

Tegmentum

involved in postural motor control; contains red nuclei (pigmented)and reticular formation

Cerebral Aqueduct connects which ventricles?

Third and Fourth Ventricles

Periaqueductal Gray Matter is found where?

Surrounding Cerebral Aqueduct

Tectum contains what?

Contains four mounds making a tectal plate

Tectal Plate gives way to pairs of what?

Pairs of Superior Colliculi

Pairs of Inferior Colliculi

Function of Superior Colliculi

Controls visual reflexes and tracking

Functions of Inferior Colliculi

Controls auditory reflexes