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NEUROANATOMY - Coggle Diagram
NEUROANATOMY
PARTS OF
THE BRAIN
Brain Stem
= relay centre cerebellum and cerebrum, connecting them to the spinal cord, subserves many involuntary functions
Medualla Oblongata
= lowest part
Pons
= bridges different parts
Supratentorial
CEREBRUM
Higher functions
Infratentorial
CEREBELLUM
balance, posture, muscle
Posterior Fossa
LOBES
Frontal Lobe
articulation
grammatical competence
writing (planning + motor)
BM 4,6,8,9, 10, 11, 46, 47, 44, 45
Parietal Lobe
writing (spatial)
sensation, time and space
BM 1,2,3,5,7,39,40
Temporal Lobe
auditory comprehension
semantics (cfr. anterior pole)
listening and memory
BM 41, 42, 20,21,22,37,38
Occipital Lobe
reading
visual processing
17,18,19
Sylvian Fissure
connects temporal and frontal lobes
Rolandic Fissure
connects frontal and parietal lobes
Cortex
Motor Cortex
= involved in planning, control, execution of voluntary movements,
organised in a somatotopic manner
Sensory Cortex
= processing and interpreting of sensory stimuli, organised somatotopically
= thin outer layer, seems grey due to
glial cells
and cell bodies, made up of
sulci
(lines,grooves) and
gyri
(spaces between)
Basal Ganglia
= grey nuclei in that interconnect the brain stem, cortex, and thalamus (red nucleus, reticular formation, substantia nigra, subthalamic nucleus, cerebral peduncle, putamen, caudate nucleus, globus pallidus)
Thalamus
= relay centre deep in the brain, processes and sends sensory and motor signals to the appropriate areas of the cortex, works closely with the basal ganglia, almost all sensory info (except smell) passes through, helps regulate sleep, consciousness, alterness
ELECTRICAL SIGNAL
At rest = inside is more negatively charged,
resting potential
is -70 milivolts
Signal starts (
Depolarisation
) = neuron triggered, sodium channels open, inside more positive, reaches threshold, creates action potential, rises to +40 milivolts
Signal ends (
Repolerisation
) = sodium channels close, potassium ions bring charge back down, sometimes it drops too low (
Hyperpolarisation
)
AXONS
Commisural tracts
= connect left and right hemispheres (e.g.
Corpus Callosum
)
Association Tracts
= connect different parts of the same hemisphere (
Arcuate Fasciculus
)
Projection Tracts
= connect cerebral cortex with lower parts of the brain and the spinal cord, carrying sensory and motor signals
Corticobulbar Tract
via cranial nerves from cerebral cortex to brain stem to facial muscles to head and neck, goes through bulbar region (lower part brain stem)
Corticospinal Tract
from cerebral cortex to spinal cord, pyramidal decussation (crossing tracts at brain stem)
Lower Motor Neurons
part of the PNS (e.g. hypotonia)
Upper Motor Neurons
part of the CNS (e.g. hypertonia)
NEUROIMAGING
Structural
Diffusion Tensor Imaging (DTI)
non-invasive
white matter tracts, tractography
great spatial resolution
Electroencephalogram (EEG)
non-invasive
Records changes in voltages
signal from 1000 neurons firing simultaneously
Epilepsy, coma, sleep studies
Great temporal but bad spatial resolution
Measures Event Related Potentials (ERPs)
Relatively cheap
Computed Tomography (CT)
non-invasive
x-rays, for first diagnoses
Magnetic Resonance Imaging (MRI)
non-invasive
magnetic fields to visualise cortex
Better spatial resolution than CT
With or without contrast
Functional
functional Magnetic Resonance Imaging (fMRI)
non-invasive
very popular in clinical experiments
Measures BOLD (blood oxygenation level dependent)
cannot differentiate feedforward/back or in/exhibitory
very expensive!
Magnetic Encephalogram (MEG)
non-invasive
Combination of EEG and source localisation
Good spatial and temporal resolution
Very expensive
Direct Electrical Stimulation (DES)
invasive
electrical stimulation during awake surgery
Positron Emission Tomography (PET)
invasive
gamma rays, metabolic processes (e.g. glucose)
Single-Photon Positron Emission
Computed Tomography (SPECT)
invasive
gamma rays, biological processes (e.g. blood flow)
NERVOUS
SYSTEM
White Matter
= subcortical areas, many myelinated axons!
Grey Matter
= cortical areas, few myelinated axons
Hemispheres
Interhemispheric tracts!
Language is situated in the left hemisphere
for most people, prosody in right hemisphere
Most parts of the brain exert contralateral control
oval-shaped, asymmetrical masses
built up out of fatty proteins
Functions
Integration of sensory info
externally (e.g. vision)
internally (e.g. proprioception)
Coordinating (in)voluntary actions
Homeostasis
= stable state, constantly measuring the internal and external environment, regulation of body temperature, blood pressure, PH, fluid balance
PNS
= connection CNS and muscles
spinal nerves, cranial nerves, rest body
CNS
= brain + spinal cord
holds superior functions (e.g. memory)
sensory processing and impulses muscles
CRANIAL NERVES
CAUSE &
INCIDENCE
Cerebrovascular accident/stroke
Haemorrhage, Ischemia (embolism, thrombosis)
Tumor/Neoplasm
Cranial Traumatism
Neurodegenerative Progressive Disorders
Infections
PROTECTIVE
MECHANISMS
Failure:
Hydrocephalus
increase volume CSF
compression non-elastic skull
due to infection, inflammation, obstruction
Solution: VA or VP shunt!
Communicative
= CSF flows normally but cannot be absorbed properly due to a blockage
Normal Pressure
= in elderly people, CSF flows normally but cannot be
absorbed properly due to a blockage
Obstructive/non-communicative
= CSF is physically obstructed , preventing it from reaching the subarachnoid space!
Membranes
Dura Mater
= exterior, has an inner and outer layer, superior sagittal sinus collects blood
Pia Mater
= inner, enrobes gyri, very thin, highly vascularised, delicate
Arachnoid Mater
= web-like middle, subarachnoid space: blood vessels and CSF
Cerebrospinal Fluid
Production of cerebrospinal fluid
lateral ventricles
Foramina of Monro
3rd ventricle
Aqueduct of Sylvius
4th ventricle
Foramina of Luschka and Magendie
Subarachnoid space
protects the immune system
Protects the brain against external shocks
protects homeostasis
aids electrical conduction
Skull
Posterior Fossa
= cerebellum and brain stem
Anterior Fossa
= frontal lobe support
Middle Fossa
= temporal lobe support
Central Skull Base
= core brain foundation
