Anatomy Intro - Lecture 1 Flashcards
intro
What is Physarum polycephalum?
What does LBA stand for?
A. Logical Block Addressing
B. Linear Ballistic Accumulator
C. Line Bisection Analysis
Who developed the diffusion model?
A. Roger Rabitt
B. Roger Ratcliff
C. Roger Randolf
Is the Subthalamic Nucleus part of the Basal Ganglia?
How much stronger is the 7 Tesla MRI magnetic field
compared to the earth magnetic field?
A. 20.000x
B. 70.000x
C. 140.000x
When the information of the cortical regions are transferred to the Basal Ganglia, is this then done in a:
A. Information segregated way
B. Information integrated way
C. There is no information transferred from the cortical
regions to the Basal Ganglia.
Describe the striatal vs. subthalamic theory of setting decision thresholds
How many subcortical structures are there in the brain? According to the Federative Community
on Anatomical Terminology (1998)
How many have been mapped with
MRI?
455
7%
Why is it so difficult to map the human subcortex?
Subcortical nuclei are small.
They lie in close proximity to
each other.
Some of them have high iron
content or neuromelanin.
What can deep-brain stimulation of the
human subcortex used to treat?
Movement
disorders
OCD
Anorexia
Depression
Chronic Pain
Cluster headache
Epilepsy
What are the three functional subdivisions in the STN?
Motivational
Cognitive
Motor
What can ultra-high field (UHF) MRI provide?
Allows the direct visualization of small subcortical nuclei.
Three major fibers connecting the limbic system (hippocampus)
The cingulum connecting the prefrontal, parietal and occipital cortex to the temporal lobe and hippocampus
The stria terminalis connecting the hypothalamus to the amygdala
The fornix, which is a projection fiber, connecting the medial temporal lobe to the mamillary bodies and hypothalamus.
5 main association fibers (connecting the cortical lobes)
The superior longitudinal orarcuate fasciculus connecting the frontal, temporal, and parietal lobe
The inferior longitudinal fasciculus connecting the temporal and occipital lobe
The superior fronto-occipital fasciculus, connecting the frontal and parietal lobe
The inferior fronto-occipital fasciculus connecting the orbital cortex to the ventral occipital lobe
The uncinate fasciculus connecting the anterior temporal lobe and lateral orbital frontal regions.
What are the five major brainstem white matter tracts?
the superior,middle, and inferior cerebellar peduncles, the corticospinal tract, and the mediallemniscus
What are projection fibers, association tracts and commissural tracts?
Projection fibers connect cortical and subcortical gray matter
Association tracts connect two cortical areas
Commissural tracts connect the brain’s hemispheres
Which brain region has the most neurons?
Cerebellum
What are the three peduncles that connect the cerebellum to the brain stem?
the superior cerebellar peduncle -> the midbrain
the middle cerebellar peduncle -> pons
the inferior cerebellar peduncle -> medulla oblonga
What are the three lobules of the cerebellum (in each hemisphere)?
anterior, posterior, and flocculonodular lobe
Degeneration of which specific, crescent-shaped, dopamine-producing region is a main hallmark of Parkinson’s disease.
The substantia nigra
Which two areas are functionally but not ontologically considered to be part of the basal ganglia?
The subthalamic nucleus (STN) and the substantia nigra
Where is the basal ganglia located?
Deep in white matter of the cerebral hemispheres anterior to the thalamus, positioned medial to the lateral ventricles.
3 regions of occipital cortex according to Broadmann’s classification
The occipital lobe consists of three areas (17–19)
The primary visual cortex corresponds to area 17
Area 18 and 19 form the visual association cortex
4 temporal cortex regions according to Broadmann’s classification
the primary auditory cortex (area 41)
Adjacent is the auditory association cortex (area 42, 22, partly overlays with Wernicke’s area)
The temporal visual association cortex (areas 20, 21, 37)
one of the paralimbic areas, occupies the temporopolar cortex (area 38)
What are the 4 regions of the parietal cortex according to Broadmann’s classification
Areas 1–3 correspond to the somatosensory cortex and its cytoarchitecture strongly resembles that of the primary motor cortex
The more laterally located areas 5 and 7 together form the superior polymodal parietal cortex
Areas 39 and 40 are located in the inferior polymodal parietal cortex, corresponding to the Geschwind’s territory
The medial parts of areas 31, 5, and 7 form the precuneus, and area 43 is considered a transition region of the fronto-parietal operculum
What are the 5 frontal cortex regions according to Broadmann’s classification?
Area 4 corresponds to the primary motor cortex, containing neuronal bodies, as well as cortico-spinal projection fibers which show a somatotopical organization
Area 6 contains the premotor region and is subdivided into the lateral premotor cortex (PMC), and the pre-supplementary motor area (pre-SMA)
Area 44 and 45 correspond to Broca’s area
Area 8–10, and 46 include dorsolateral prefrontal areas, and 47 to the ventrolateral prefrontal corex
areas 11 and 47 represent the main parts of the orbitofrontal cortex
Brain components overview:
Brain components :
Surface-level bulges & spaces
Gyri (bulges)
Sulci (spaces)
– Sylvian Fissure
– Central sulcus
Brain components:
Neurons
Parts:
cell body
axon
axon terminal
dendrite (input)
synaptic terminal (output)
astrocyte
nudeus
Several types, complex networks
Brain components:
Glia - Microglia
Microglia:
- Phagocytotic (they clean up)
** Activated microglia are hypothesized to give rise to MRI differences as observed in the substantia nigra of Parkinson patients
Brain components:
Glia - Astrocyte
- Control the microenvironment around the neurons
- Provide structural integrity
- Important in maintaining the blood brain barrier
Brain components:
Glia - Oligodendrocytes
Oligodendrocytes
- Important for myelination of neurons
- CNS
- Formation: 4 mo of preg - 2nd decade of life
- Myelinates mulitple axons
** When the myelin system fails: Demyelinating disease (MS), can exist for a long time
Schwann cells: Oligodendrocytes of the PNS
Brain components:
Glia - Ependymal cells
Line ventricular cavities and the central canal of the spinal cord
Brain components:
Lobes - Frontal
Primary motor cortex
– Damage: Contralateral spastic paresis (a weakening of voluntary movement)
Premotor cortex
– Damage: Apraxias (inability to perform purposeful actions)
Brain component Orientation:
Lobes - Frontal
premotor ctx
motor ctx
prefrontal
Brain components:
Lobes - Frontal - Motor homunculus
Muscles of the head:
Ventral: closest to lateral fissure
Dorsal: neck, upper limbs, trunk on lateral aspect
Medial: pelvis and lower limb
** Supplied by branches of the anterior cerebral artery
Brain components:
Lobes - Frontal - Prefrontal
Located rostral to premotor area
- ¼ of human cerebral cortex
- Organizing and planning of intellectual and emotional aspects of behavior
Lesions
– Loss of concentration
– Distraction
– Lack of initiative, foresight and perspective
– Apathy
– Suckling and grasp reflexes are evident
(Late-stage Alzheimer’s Symptoms)
LEFT-frontal:
Expressive Aphasia
- Area in left or dominant hemisphere affected
- Damage to Broca’s area produces motor, nonfluent/expressive aphasia resulting in difficulty to produce expressive speech
Brain components:
Lobes - Parietal
Primary somatosensory cortex
– Begins posterior to the central sulcus (postcentral gyrus)
Post-central gyrus
Sensory homunculus:
– Head, neck, upper limbs and trunk laterally
– Pelvis and lower limbs medially
Posterior parietal association cortex
– Lesions in the dominant hemisphere result in apraxia (inability to perform purposeful movements)
– Astereognosia may be present (inability to recognize objects by touch)
– No loss of tactile or proprioceptive sensations
Receptive aphasia
- Inability to comprehend spoken language
- Possible inability to read (alexia)
- Fluent verbalization, that lacks meaning
- Unawareness of the deficit
Brain components:
Lobes - Occipital
Primary visual cortex
- Retinal surface orderly represented
– Damage produces scotoma
– Lesions produce contralateral hemianopsia
Brain component Orientation:
Lobes - Temporal
. Angular
Wernicke’s
Area 41
Area 42
Broca’s
- Angular Gyrus
- Broca’s (area 44, 45)
- Wernike’s (area 22)
A-1 Region: - Transverse Temporal
gyrus of Heschl (area 41) - Area 42
Brain components:
Lobes - Temporal
Primary auditory cortex
– On the two transverse gyri
of Heschl
– Cross the superior
temporal lobe deep within
the lateral sulcus
– Unilateral lesions result in
difficulties locating sounds
in the contralateral field
Brain components:
Cerebellum
- Derived from metencephalon
- Dorsal to pons and medulla
- 4th Ventricle between pons and cerebellum
- Fine tuning of movement and muscle coordination
Cerebellar lesions:
- Tremor with intended movement without paralysis or paresis
- Ipsilateral symptoms
- Posture, gait or balance are affected by lesions
Brain components:
Cerebellum - Microzones
Deep cerebellar nuclei:
- GABA/Purkinje
- Glutamate/mossy and climbing fibers
Brain components:
Thalamus
Major relay for ascending tactile, visual,
auditory, and gustatory information to the
neocortex
~ 25 individual nuclei
Brain components:
Hypothalamus
- Water balance
- Adenohypofysis (releasing factors)
- Neurohypofysis (hormones)
- Hunger
- Autonomic regulation
- Thermoregulation
- Sexual urges and behavior
- ~25 individual nuclei
Brain Components:
Basal Ganglia
Striatum
– Caudate nucleus
– Putamen
Globus pallidus
– Externa
– Interna
Substantia Nigra
Subthalamic nucleus
Brain Components:
Ventricular system
- Brain and spinal cord are in a bath of protective
CSF - Constant production by the Choroid Plexus
- Four ventricles
– 2 lateral ventricles deep in each hemisphere
– 3rd ventricle midline diencephalon
– 4th ventricle, dorsal surface of the pons, and upper medulla - Ventricles are connected and CSF flows through
Brain Components:
Ventricular system - CSF
Cerebrospinal fluid
- Lateral ventricles è
- interventricular foramen of Monro è
- third ventricleè
- cerebral aqueductè
- fourth ventricleè
- subarachnoid space either through the foramen of Magendie or of Luschska
Sidestep: Hydrocephalus
Brain Components:
Blood Brain Barrier
Formed by capillary endothelium, connected by tight junctions
- Astrocytes important for maintenance
- Numerous long processes with expanded vascular end foot attaching to capillary walls
- Water goes through passive diffusion, for most molecules active transport is needed
What can and what can we
not see with MRI in vivo?
- Cortical folding?
- Borders between cortical areas?
- Individual cells?
- Signal from neurons or glia?
- Lesions?
- Activation or inhibition?
- Deep cerebellar nuclei?
- Thalamic and hypothalamic nuclei?
- CSF?
- Cortical folding?
- Borders between cortical areas?
- Individual cells?
- Signal from neurons or glia?
- Lesions?
- Activation or inhibition?
- Deep cerebellar nuclei?
- Thalamic and hypothalamic nuclei?
- CSF?
Orientations
. Dorsal/Superior
Rostral (<eye)rat Caudal
Ventral/Inferior
Orientations - Lobes
.frontal parietal
occipital
temporal
Sagittal plane
divides the brain in a left and right part
Axial/Transverse plane
divides the brain in inferior and superior parts
Coronal/Frontal plane
the vertical plane perpendicular to the sagittal plane
Dorsal/Superior
Ventral/Inferior
Rostral & Caudal
Distal & Proximal
Directional orientations:
indicates location of an area relative to another area
Distal: moving away from
Proximal: moving towards
Ipsilateral & Contralateral
Bilateral & Unilateral
Ipsi: (connections between areas)
on the same side
Contra: (connections between
areas) on different sides
Bilateral: present in both hemispheres
Unilateral: present in one hemisphere
