Cerebral Cortex Flashcards
What part of the neural tube forms the brain
Rostal part of the neural tube
What part of the neural tube forms the spinal cord?
Caudal part
What become the Forebrain?
What does this develop into?
Prosencephalon becomes the forebrain
It develops into the Telencephalon and Diencephalon @ 7 weeks
which go onto form the 2 cerebral hemispheres
what becomes the midbrain?
Mesencephalon
what becomes the hindbrain?
Rhombencephalon
What are the 4 lobes of the Cerebral cortex?
- Frontal
- Parietal
- Occipital
- Temporal

What can happen at the poles?
Contusion a.k.a bruising
on frontal, temporal, occipital lobes
which lobe does not have a pole?
Parietal
What are the parts of the Forebrain?
- Cerebral hemisphere
- Olfactory bulb
- Diencephalon
what are the parts of the Cerebral Hemisphere?
- Cerebral cortex
- Basal Ganglia
- Various small nuclei
What are the parts of the Diencephalon
- Thalamus
- Subthalamus
- Hypothalamus
- Epithalamuc (a.k.a Pineal gland)
Is brain shrinkage a normal process?
Yes with ageing it is
- @ 70 - 5% lost
- @80 - 10% lost
- @90 - 20% lost
Cortex
Outer layer of gray matter - 1-4mm thickness
Controls all of cognition
What is the gateway to the Cortex?
What doesn’t go through here?
The Thalamus
Only Olfaction (sense of smell) doesn’t go through here, it goes direct to the cortex
Result of Cortical Damage to
Primary Somatosensory Cortex:
- somatosensory anaesthesia (loss of touch).
- Pain remains intact (= parieto-insular supplementary area)
Result of cortical damage to
Supplementary somatosensory areas
Superior Parietal Lobe:
- contralateral somatosensory agnosia
- (inability to recognise common objects by palpation alone: = touch and proprioception)
Result of cortical damage to
Supplementary somatosensory areas
Inferior Parietal Lobule:
in the dominant hemisphere
- (Left) concerned especially with language (alexia).
Damage of non-dominant hemisphere
- = bizarre disturbances of “body image”
- known as somatosensory disregard:
- eg patients ignore parts of their body, believing they belong to someone else (contralateral to lesion) in spite of the fact that the body part is not anaesthetic to any stimulus
What is critical for memory?
where does this sit?
Hippocampus
Sits in the temporal lobe
This degenerates in Alzheimer’s pts
Homunculus
Degree of innervation is proportional to the organ size representation
larger the innervation the larger the organ size on the homunculus
Cortical Connections
Ascending Connections:
Somatosensory from the thalamus:
- (inputs from spinal cord via VPL, and trigeminal via VPM)
Auditory:
- from the thalamus (inputs from the cochlea via the medial geniculate nucleus)
Visual:
- from the thalamus (inputs from the retina via the lateral geniculate nucleus)
Smell
- (direct into the olfactory cortex) and Taste (via VPM)
Complex information from the cerebellum and basal ganglia via the thalamus
Corical connections
Descending Connections
- Motor to the spinal cord (corticospinal tract)
- Motor to the brainstem motor nuclei (cortico-bulbar tract)
- To the motor control centres (targeted to the basal ganglia and cerebellum)
- To the limbic system
Cortical connections
Connections within the cerebral cortex
On same side:
- association fibres connecting different brain regions
On opposite sides:
- commissures including the corpus callosum
Where does the visual cortex lie?
In the OCCIPITAL LOBE
Primary sensory and motor areas on the medial surface
picture
