Week 3 Lecture Flashcards
(211 cards)
cerebrum
largest and most prominent area of the brain
- has both gray and white matter
- contains cerebral cortex as well as several subcortical structures like the hippocampus, basal ganglia, thalamus, limbic areas, and olfactory bulb
cerebral cortex
part of the cerebrum
- made of neuron cell bodies and their dendrites
- only gray matter
- forms a complete covering of the cerebral hemisphere
- vary in thickness from 2-4 mm
cortex organization
horizontal “laminar” (6-layer) organization and a vertical “columnar” structure
3 types of neurons in the cortex
pyramidal cells, spiny stellate cells, smooth stellate cells
pyramidal cells
excitatory and make excitatory connections with neighboring pyramidal cells
- primary output cells of the cortex
- largest
spiny stellate cells
type of granule neuron (small interneuron) that have a star-like shape formed by dendritic processes radiating from the cell body
- dendrites densely covered in spines to receive high levels of input from other neurons
- receive most of their input from the thalamus and other cortical areas
- form excitatory connections with pyramidal cells
smooth stellate cells
- non-spiny dendrites and are inhibitory neurons
- they receive input from pyramidal cells and form inhibitory (GABAergic) synapses w/ other pyramidal cells
- type of granule neron
laminar organization
the horizontal layers of the cortex
- 6 layers based on cell types and their connections that are generally found in the cortex
- mechanism for sorting its inputs and outputs
- afferents form other cortical areas
- the thalamus distribute themselves in distinctive spatial patterns in specific cortical lamina
molecular layer position and main connections
first layer; dendrites and axons from other layers
small pyramidal layer position, main connection, and alt name
second layer; cortical-cortical connections; external granule layer
medium pyramid layer position, main connections, and alt name
third layer; cortical-cortical connections; external pyramidal layer
granular layer position, main connection, alt name
fourth layer; receives input from thalamus; internal granule layer
large pyramidal layer position, main connections, and alt name
fifth layer; sends outputs to subcortical structures (other than thalamus); internal pyramidal layer
polymorphic position, main connections, and alt name
sixth layer; sends outputs to thalamus; multiform layer
layer 1 composition
mainly dendrites for neurons from deeper layers as well as axons
layers 2 & 3 composition
neurons that project mainly to other areas of the cortex
layer 4 composition
receives the majority of the inputs from the thalamus
layer 5 composition
projects mostly to subcortical structures other than the thalamus like the brainstem, spinal cord, basal ganglia, and the other cortical hemisphere via corpus callosum
layer 6 function
projects mainly to the thalamus
cortical organization
groupings of functionally connected neurons that extend vertically through all layers of the cortex
- commonly referred to as minicolumns
minicolumn
a group of 80-120 neurons arranged together functionally (via their connections and co-dependent activity)
- about 2x10^8 minicolumns in the human cortex
Brodmann map
splits the cortex into over 50 different areas
three parts of cortex
sensory, motor, and association areas (some include limbic as 4th)
sensory areas of the cortex
receive information related to sensation, with different areas corresponding to different senses