cerebral cortex Flashcards
Every cubic inch of cerebral cortex has about ____ miles of nerve fibers
10,000
The number of neurons in the brain is about ___ times greater than the number of humans on the planet
30
Typically a neuron is wired to about how many of its neighbors?
1000-2000
What is the advantage we have by being good at storing and processing sensory information?
We are better in effective responses to our environment
Most cortical neurons are a site of _____ input from multiple neurons
Converging
Most cortical neurons are a source of _____ output to multiple neurons
Diverging
What is Layer 1 of the cerebral cortex?
Molecular layer; mostly axons
What is Layer 2 of the cerebral cortex?
External granule layer
What is layer 2 made up of?
Granule (stellate) cells
What is the 3rd layer of the cerebral cortex?
External pyramidal layer
What is Layer 3 made up of?
Primary pyramidal cells
What is layer 4 of the cerebral cortex?
Internal granule layer; main granular cell layer
Most incoming sensory signals terminate in which layer of the cerebral cortex?
Layer 4
What is layer 5 of the cerebral cortex?
Internal pyramidal layer
Layer 5 is dominated by what?
Giant pyramidal cells
What is layer 6 of the cerebral cortex?
Multiform layer
What types of cells are found in layer 6?
All types; pyramidal, stellate, fusiform
Name the 3 major types of cells in the cerebral cortex?
Pyramidal
Granule
Fusiform
Which type of cell is a major efferent cell?
Pyramidal
____ cells are the least common of the three
Fusiform
Which cells give rise to output fibers from cortex?
Fusiform
Which cells are a source of cortiospinal projections?
Pyramidal
Granule cells have ___ axons
Short
Excitatory neurons release what?
1° glutamate
What do inhibitory neurons release?
1° GABA
Short axons of granule cells function as what?
Interneurons (intra cortical processing)
Most output leave the cortex via which layer(s)?
5 and 6
Spinal cord tracts originate from layer __
5
____ connections are from layer 6
Thalamic
Most intracortical association functions are in layer(s) ____
1,2,3
All areas of the cerebral cortex has extensive ___ and ___ connections with deeper structures of the brain (eg. Basal ganglia, thalamus)
Afferent; efferent
____ connections are extremely important and extensive
Thalamic
Which neurons can change their function as functional demand changes?
Cortical neurons
