0916 - Organisation of the Cortex

Question 1

What are the three different types of cortex?

Answer 1

Paleocortex/Entorhinal Cx (Limbic system) - Paleostriatum (globus pallidus) - consists of Olfactory cortex plus emotional motor system, interoception.

Archicortex - Hippocampus - Archistriatum (amygdala) - Role in memory of places and spatial relationship

Neocortex - The rest - Neostriatum (caudate/putamen).

Question 2

How does the archicortex relate to the deep cerebral nuclei?

Answer 2

Extensive connections with medial thalamus, hypothalamus, amygdala and entorhinal cx. It is about where you are in the environment (spatial relationships). Afferents come from all over cortex.

Main output is the fornix. Goes to septal area, diencephalon (anterior thaalamic nucleus) and C/L hypothalamus and hypothalamus, as well as Cx.

Archicortex (Hippocampus) - Archistriatum (amygdala).

Question 3

How does the paleocortex relate to the deep cerebral nuclei?

Answer 3

Forms a ring around the core of the brain.

Question 4

List the components of the limbic lobe and describe their functions

Answer 4

Limbic cortex

Cingulate gyrus - Pain and emotion.

Enterorhinal cortex

Amygdala - Alarm system based on functional fear. Mediates adaptive responses and the MOST powerful regulator of hypothalamus/endocrine functions.

Hippocampal formation - Learning and memory formation by processing and categorising new info, and modulates aggression/rage and endocrine functions of hypothalamus.

Septal area - Relay nucleus for hippocampus to hypothalamus. Control of aggression and rage, endocrine regulation, reward/pleasure.

Question 5

Describe the laminar organisation of the neocortex.

Answer 5

6 Layers. Generally input to layer IV, between columns and hemispheres in layers 2/3 (commisural and association), and outputs (projection) in 5 and 6.