Egleton - External Brain Morphology Flashcards
Forebrain:
Telencephalon
Cerebral hemispheres (Cortex, white matter, basal ganglia, basal forebrain nuclei)
Most recently evolved part of the brain
Midbrain: Mesencephalon
Cerebral peduncles, midbrain tectum, midbrain tegmentum
Chief role: vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation
Hindbrain:
Metencephalon
Cerebellum
Roles: Balance, equilibrium, posture, muscle tone, coordination, timing fo learned skilled motor movements, correction of errors while moving
Midline of Cerebellum = Vermis
Rounded lobule on the bottom of each hemisphere = Tonsil
Pons
Bridges brain to cerebellum via pontine nuclei
Dorsal Zone w/ CN V, VI, VII; Ventral contain pontine nuclei and corticospinal rtact fibers
Forebrain:
Diencephalon
Thalamus (dorsal):
Many relay nuclei, which project into cortex
Hypothalamus (ventral):
CNS center for regulation of autonomic and endocrine activity to maintain homeostasis
Mesencephalon: Tectum
Dorsal to cerebral aqueduct of Sylvius (can be blocked by lesions)
Involved in visual and auditory reflexes
Pineal tumors can occur in this region, and can cause non-communicating hydrocephalus
Mesencephalon: Tegmentum
Extends from aquaduct to substantia nigra
CN III, IV, red nucleus
Mesencephalon: Basal Portion
Substantia Nigra located here; major area which degenerates in Parkinson’s
Crus Cerebri located here
Hindbrain:
Myelencephalon
Medulla
Site of Pyrimidal decussation (85% fibers, 15% at level of origin)
Contains vital respiratory and cardiovascular centers
CN IX, X, XI, XII
Clinical: Tonsillar (Transforaminal) Herniation
Occur when lesions push cranium downward; tonsil of cerebellum herniates into the foramen magnum, compressing the medulla
Olive
Part of the lateral medulla
What structures just beneath chiasm of the Optic Nerve?
Median Eminence part of Hypothalamus
Infindibulum (stalk of Pituitary)
Mamillary Bodies (part of hypothalamus)
Cerebral Peduncle (crus cerebri)
What line separates the Temporal lobe from the Frontal and Parietal lobes?
What line separtes the Frontal and Parietal Lobes?
What line separates the Parietal Lobe from the Occipital Lobe?
Lateral Sulcus (Sylvian FIssure)
Central Sulcus (Rolandic Fissue)
Parietooccipital Sulcus
Three Major Functions of Cerebral Cortex
- Primary Motor and Sensory
- Higher-order Motor and Sensory (regulate primary)
- Association Areas (highest order–decision making, personality)
Importance of Allo-cortex
Memory, Learning
Brodmann’s Area - Frontal Lobe
Pre Central Gyrus (Area 4)
Primary Motor Cortex
Majority of axons in corticospinal tract, somatotopically organized
Face = lateral, legs = center, arms = between face/legs
Brodmanns Areas - Frontal Lobe
Superior and Inferior Frontal Sulci (Area 6, Area 8)
Area 6/8
6: Consists of supplementary/premotor areas, contribute to corticospinal tract
8: Paired eye movements to contralateral side, lesion causes deviation towards lesion
Brodmass Areas - Frontal Lobe
Area 44 / 45
(Pars Triangularis / Opars Operularis)
(In Dominant Hemisphere)
44/45 = Broca’s Area; motor production of language
Usually Left = Language
Damage = Understand o.k. , difficulty forming language fluently, extreme case become mute
Clinical/Broddman
Prefrontal Association Cortex
[Dorsolateral Prefrontal Cortex (dlPFC)]
Large role in executive function
Clinical: Substance abuse disorders can alter this process
Brodman:
10, 11, 12 (medial)
24, 25, 32 (ventral)
Clinical/Broddman
Limbic Association Cortex
Areas 10, 11, 12
Areas 24, 25, 32
Main Function: Personality, Social behavior
Clinical: Lesions produce marked changes in personality and social behavior
Temporal Lobe portion of the Limbic Association Cortex
Critical role in learning & memory
Clinical: Large, bilateral lesion of the prefrontal cortex?
Impaired decision making, emotional lability, social disinhibition, impulsiveness
***Phinease Gage***
Broddman Area - Parietal Lobe
Postcentral Sulcus/Gyrus - Area 3, 1, 2
Lesions?
Primary Somatosensory Cortex
Important for pain, temperature, discriminative touch, pressure, vibration, proprioception
Somatotopic Organization similar to motor cortex
Clinical: Lesions produce deficits with features listed above. Stem hint, “I can feel pain, but can’t localize it”
Broddman Area - Parietal Lobe
Intraparietal Sulcus - Part of Area 2, Part of Area 5
Lesions?
Higher order somatosensory areas; major role in integrating visual and somatosensory information
Clinical Lesion: Individual can recognize something on basis of touch alone, or somatosensory agnosias
Broddman Area - Parietal Lobe
Infraparietal Parietal Lobule:
Supramarginal (Area 40)
Angular Gyri (Area 39)
Lesions?
Major role in perception and interpretation of written language (include sight reading music)
Clinical: Lesion in area show loss of ability to read, write
“Musician suddenly can’t read their music”
