Lesson 2 Flashcards
biggest area in the brain
Contains cerebral cortex
Outermost: gray matter
Inner most: white matter
Cerebrum
Functions of the Cerebrum
- Receives input from sense organs (via afferent neurons)
- Controls MOVEMENT and POSTURE
- Stores records/MEMORY
- HIGHER MENTAL functions
- Manages EMOTIONS
bone part of the coverings of the cerebrum
Skull/ Cranium
Thickest, outermost layer
Lines cranial cavity and vertebral canal
Covers cranial nerves
Dura mater (“Pachymeninx”)
2 Layes of Dura mater
Meningeal (inner layer) and Periosteal (closer to the bone)
Found in between meningeal and periosteal
confluence of venous sinuses or face drainages
Divides 2 cerebral hemispheres (left & right)
Falx Cerebri
Divides 2 cerebellar hemispheres
Falx Cerebelli
Separates
Cerebellum from Occipital lobe
Tentorium Cerebelli
Covers the Sella Turcica (protects pituitary gland)
Diaphragmatic Sellae
Middle layer
Thin and transparent
Doesn’t follow convolutions
Avascular, meaning it has no blood supply
Arachnoid mater
- inside the arachnoid mater
- houses:
Cerebrospinal Fluid and Arterial system
Cisterns
Subarachnoid space
Thinnest, innermost layer
● Follows convolutions
● Highly vascularized to supply nutrients
and oxygen to the brain
● No actual or potential space below it
Pia mater
below dura mater
Subdural space
Acts as buffer space
Contained in the subarachnoid space
Other functions include:
○ Shock absorption
○ Conveying of nutrients
○ Removing byproducts of metabolism
○ Lymphatic system of CNS
Produced by Choroid Plexus and drained by Arachnoid villi
On average, 500 mL of CSF is produced daily
The typical level of CSF is 100-150 mL
Cerebrospinal Fluid
What condition can it lead to if the CSF went beyond typical level of 500 mL?
Hydrocephalus
Elevated (paangat) portion of the brain’s
surface
Consists of gray matter (unmyelinated)
Contains neuronal cell bodies and dendrites, which are involved in processing and integrating information
Gyrus
Shallow groove (depression/palubog) on the brain’s surface
Consists of white matter (myelinated)
Contains axons
Sulcus
Deeper groove than the sulcus
Fissure
folded structure (composed of both gyri and sulci) for increasing the brain’s surface area which ultimately contributes to more areas for processing
convolutions
Involved in risk-reward behavior and emotional PROCESSING, as it is connected to the limbic system.
Plays a role in autonomic functions, such as respiration and heart rate regulation.
It is connected to all lobes of the brain except the occipital lobe
Feeling of physical effects of emotions
Insular
Responsible for mood regulation and EMOTIONAL RESPONSES.
Includes structures like the uncus, cingulate gyrus, and amygdala.
Plays a role in forming unconscious
associations, particularly in relation to smell, sight and emotions.
Limbic
Divides the Right and Left cerebral
hemisphere
Longitudinal Cerebral Fissure
Separates the frontal & parietal lobe
Central Sulcus (Fissure of Ronaldo)
Separates the parietal and occipital lobe
Parieto-Occipital Lobe
Separates the temporal and parietal lobe
Lateral Cerebral Fissure (Sylvian Fissure)
Separates the lingual gyrus and cuneus
Calcarine Fissure
Separates the insular lobe from the rest of the brain
Circular Sulcus
Left hemisphere; 90% of population
Thinking part → analytical, logical, language, speech
DOMINANT HEMISPHERE
Right hemisphere; remaining 10%
Spatial recognition, facial recognition, music, arts, emotions
NON-DOMINANT HEMISPHERE
● Most important area in motor functions
● Voluntary muscle activation of the C/L
limb
○ Final station for conversion of the
motor plan into execution
● Axons descend as corticospinal tractand
become the motor nerves once they exit
the spinal cord
● Does not plan only execute
● Betz cells (large pyramidal cells for motor output)
Area 4: Primary Motor Area
Lesion of Area 4
C/L Paralysis (cannot move)
C/L Flaccidity (cannot move due to zero tone/muscle readiness)
Stores knowledge/programs of motor activity
Plans the coarse postural movements together with the Basal Ganglia
Can help in muscle activation only if the stimulation is very strong
Motor output is planned in this area and then the plan is transferred to Area 4 for execution
No Betz cells
Area 6: Supplementary Motor Area/Premotor Cortex
Lesion of Area 6
C/L Incoordination and Spasticity (abnormal muscle tightness due to
prolonged muscle contraction)
- Voluntary conjugate eye movements to the C/L side independent of visual stimuli
- Connects to occipital eye eld via
association fibers
Area 8: Frontal Eye Field
Lesion on Area 6
C/L Incoordination and Spasticity
Executive functions
● Individual personality
● Regulates emotions/depth of feeling
● Has an extensive connection to the
thalamus and limbic system
Area 9, 10, 11, 12: Prefrontal Cortex
Lesion on Area 9, 10, 11, 12
Left hemisphere: cautious and
depressed
Right hemisphere: impulsive
Motor part of speech
○ Has connections to Area 4
Area 44, 45: Broca’s Motor Cortex
Lesion on Area 44, 45
Dominant (L-side):
Broca’s/Motor/Non-uent aphasia
(can understand what to say but
cannot say it)
○ Non-dominant (R-side): Aprosody
(monotonous when speaking)
Receives and processes all sensations, except olfaction, from C/L side
Some sensations from the I/L oral
region
Sensations from the pharynx, larynx, and perineum
Area 3, 1, 2: Primary Somesthetic Area
Lesion on Area 3, 1, 2
C/L Hemianesthesia (loss of
sensation in either lateral half of the
body) or sensory disturbances
Receive and integrate different sensory
stimuli
○ C/L touch localization
○ Response to transient cutaneous
stimuli
○ Environmental exploration
● Receives signals from Area 3, 1, 2,
thalamus, and auditory and visual cortex
Area 5, 7: Secondary Sensory Area
Lesion on Area 5, 7
Astereognosis (inability to recognize
objects by touch)
Gnostic
○ Recognize previously learned
information
Area 39: Angular Gyrus and Area 40: Supramarginal Gyrus
Lesion on Area 39
Lesion:
○ Dominant (L-side): Alexia (inability to read) and Agraphia (inability to write)
○ Non-dominant: Gerstmann Syndrome
■ Left and right disorientation
■ Finger agnosia
■ Agraphia
■ Acalculia (inability to do simple
math)
Lesion on Area 40
Apraxia
■ Dominant: ideomotor (inability to
perform tasks when commanded)
and ideational (has an idea on
how to do the action but cannot
perform the action)apraxia
■ Non-dominant: dressing (inability
to dress), constructional (inability
to copy drawings or 3D
constructions), geographic
apraxia
■ Bilateral: complex visual, spatial,
and language defects
Hearing
Under Sylvian Fissure
Area 41: Primary Auditory Area
Lesion on Area 41
Partial deafness in both ears
■ greater loss in contralateral side
Interpretation of sounds
Association of auditory input with other sensory information
Receives impulses from Area 41 and thalamus
Area 42: Auditory Association Area
Lesion on Area 42
Acoustic Verbal Agnosia (inability to interpret or recognize verbal sounds)
Understanding taste sensation
Area 43: Gustatory Area
Lesion on Area 43
causes different interpretations of
taste (e.g. tasting sourness from a
sweet food)
● Language comprehension
○ written and verbal
● Reading, understanding, speaking
Area 22: Wernicke’s Area
○ Dominant (Left Side)
■ Wernicke’s/Sensory/Fluent/Recep
tive Aphasia (cannot comprehend
what they are saying)
○ Non-dominant (Right Side)
■ Affective aphasia
● Can’t understand/interpret
emotion in others’ voice
■ Amusia
● Can’t appreciate sounds heard
Lesion on Area 22
Also known as Calcarine Area or Occipital
Eye Field
● Vision
● Reex conjugate eye movements with
tracking of objects
○ Involuntary following of moving
objects (e.g. not having to think about
tracking a car you placed your bet on
using your eyes in a race, noticing a
ballpen that fell out of your desk)
Area 17: Primary Visual Area
Lesion on Area 17
○ Complete: Blindness, crossed
homonymous hemianopsia
○ Upper half: Inferior quadrantic
hemianopia
○ Lower half: Superior quadrantic
hemianopia
Also known as Visual Association Area
● Integrates visual information from Area 17
Area 18, 19: Secondary Visual Area
Lesion 18, 19
○ Loss of ability to recognize objects in contralateral eld
○ Dyschromatopsia (color /blindness)
○ Prosopagnosia (can’t point out
familiar faces)
Fluent: No
Comprehends: No
Repeats: No
Global Aphasia
Fluent: No
Comprehends: No
Repeats: Yes
Mixed transcortical aphasia
Fluent: No
Comprehends: Yes
Repeats: No
Broca’s Aphasia
Fluent: No
Comprehends: Yes
Repeats: Yes
Transcortical Motor Aphasia
Fluent: Yes
Comprehends: No
Repeats: No
Wernicke’s aphasia
Fluent: Yes
Comprehends: No
Repeats: Yes
Transcortical sensory aphasia
Fluent: Yes
Comprehends: Yes
Repeats: No
Conduction aphasia
Fluent: Yes
Comprehends: Yes
Repeats: Yes
Anomic aphasia
90% of the cerebral cortex (2-4 mm thick)
○ Indicates that cerebral cortex is not that thick
Gray matter (cerebral cortex)
Isocortex / Neocortex (GM)
With basic 6 layers
Homotypical
Cells produce only 1 sensory
modality; Surrounds primary areas
Unimodal association areas
Receive input from multiple
unimodal areas
Heteromodal association areas
Basic 6 layers are not present
Heterotypical
Poorly developed
NO Layers 2 and 4
Agranular
Within cerebral cortex; opposite is
extrapyramidal
○ Principal efferent neurons
i.) motor neurons
ii.) found in Area 4
○ Betz Cells - giant pyramidal cells
Pyramidal
Small, numerous, polygonal
Multiple branching dendrites and
one short axon
Stellate
Helps with motor functions
Some dendrites extend from Layer 6 to Pia mater
Multiform/ Polyform/ Fusiform
Small, fusiform
In supercial layers (layers 1-2)
Axons run parallel to cortical
surface and connects with
dendrites of pyramidal cells of
Layers 3 and 5
Horizontal cells of Cajal
Small, multipolar
In all Levels
Cells of Martinotti
Dense network of tangential nerve
bers (Cajal)
Many synapses
Has all types of cells
Molecular (plexiform)
Cells are:
■ Small, pyramidal
■ Stellate
■ Martinotti
Mnemonics: PMS
External Granular
Cells are:
■ Large Pyramidal
■ Martinotti
Mnemonic: PM
External Pyramidal
Afferent fibers
○ Cells:
■ Large pyramidal
■ Stellate
■ Martinotti
🫵 Outer band of Baillarger
(found in visual cortex)
Internal Granular
Efferent Fibers
○ Start of Lateral Corticospinal/Pyramidal tract
○ Cells:
■ Large and Medium
Pyramidal
■ Stellate
■ Martinotti
🫵 Inner band of Baillarger
Internal Pyramidal
Many pyramidal cells that connect cortex to thalamus
Cells:
Pyramidal
Multiform
Martinotti
Multiform Layer
Paleontologically old
Includes paralimbic areas
Transitional area
○ Sometimes they have 3-6 layers,
depending on its distance to isocortex
Mesocortex / Juxtalocortex
Includes limbic system
Has 3 horizontal layers:
○ Paleocortex - for olfaction
○ Archicortex - for olfaction
○ Periallocortex
Allocortex / Archicortex
Together with Allocortex: forms the Limbic Telencephalon
Corticoid areas
Connects left and right hemispheres
Commissural Fibers
Large bundle of myelinated and
unmyelinated bers
○ Contains commissural fibers
○ Unies attention and awareness
between hemispheres
○ E.g. Sharing of learning
Corpus Callosum
Parts of Corpus Callosum
Rostrum, Genu, Body, Splenium
Connects hippocampus of both
hemispheres
Hippocampus is responsible
for learning and memory
○ Efferent system of Hippocampus
Commissure of the Fornix/Hippocampus
Connects 2 olfactory bulbs and
temporal lobe
Anterior Commissure
Related to inferior part of stalk of
pineal gland
Posterior Commissure
Connects 2 regions within a hemisphere
● E.g. uncinate facivulus, arcuate fasciculus,
superior and inferior longitudinal fasciculus
Association Fibers
Connects the cerebrum to the lower parts of the NS i.e. the midbrain, brain stem, etc.
Projection Fibers
compact band at the upper part of the brainstem where the efferent and afferent fibers pass
Internal Capsule
radiating projection fibers of the internal capsule
Corona Radiata
Behavioral and emotional responses
● Includes behaviors for survival such as feeding, reproduction, caring for young, and fight or flight
Limbic System
Olfactory sensation
Connected to CN1 (nose)
Appropriate behavioral responses to scents
Uncus
Memory
● Encoding and retrieval of memories with
appropriate behavioral responses
Parahippocampal Gyrus
Emotions and behavior
● Autonomic functions
Cingulate Gyrus
Memory and learning
Seat of short-term memory
Lesion: Anterograde amnesia, cannot
make new memories
Hippocampus
● Emotional and sexual behaviors
● Lesion: Kluvery-Bucy/Hypersexual
behavior
● Almond-shaped mass of gray matter
● Related to the limbic system
● No known motor function
Amygdala
Also called the “Island of Reil”
● Important for planning or coordinating
articulatory speech movements
● Consists of tissues that form the oor of the
deep lateral aspect of the Cerebrum
Insula
Chemical messengers that allow the neurons
to communicate with each other
Through the formation of synapses
Neurotransmitters
Neuromuscular junction, autonomic ganglia, parasympathetic neurons
Acetylcholine (ACh)
GABA
main inhibitory
Glutamic acid
main excitatory
Masses of gray matter within the cerebral
hemisphere
Essential in motor control
Basal Nucleus
Main Components of Basal Nucleus
Caudate nucleus
Putamen
Globus Pallidus
Parts of extrapyramidal system
○ Corpus striatum
○ Subthalamic nucleus
○ Substantia nigra
○ Red nucleus
○ Brain stem reticular formation
Functions of Basal Nuclei
- Cognitive aspects of motor movement
- Sensorimotor integration
- Limbic Function
Caudate Nucleus + Putamen + Globus Pallidus
Corpus Striatum
Caudate Nucleus + Putamen
Striatum
Putamen + Globus Pallidus
Lenticular Nuclei
● Large C-shaped mass of gray matter
● Helps with feedback
● Has divisions:
○ Head
○ Body
○ Tail
● Continuous with the Globus Pallidus and
Putamen
Caudate Nucleus
Large, convex, gray mass
Afferent; receives projection from:
○ Premotor area
○ Primary motor area
○ Somatosensory area
Putamen
● Major site of input to Basal Ganglia
○ Receives afferent via the corticostriatal
projections from the cerebral cortex
○ Receives inputs from the intralaminar
thalamic nuclei, substantia nigra,
amygdala, hippocampus, and midbrain
raphe nuclei
● Sends inhibitory (GABA-ergic) axons to
Globus Pallidus (GPI)
STRIATUM (Caudate Nucleus + Putamen)
Small, light, medial portion of lenticular
nucleus
● Sends inhibitory axons (GABA-ergic)
Globus Pallidus
Efferent; Major outow of the Basal
Ganglia
GP Interna
Thin sheet of gray matter
Connects cortical and subcortical areas
Claustrum
● Lens-shaped area of the diencephalon
● Medial to the internal capsule, ventral to
thalamus, rostral to substantia nigra
● Important subcortical station for regulation
and control of voluntary muscular activities
● Excitatory (Glutaminergic)
Subthalamic Nucleus
Has large multipolar neurons containing
melanin
● Found throughout the length of the midbrain
SUBSTANTIA NIGRA
