V. Natural & Analog Computation
A Very Brief Tour of
Real Neurons
(and Real Brains)

Slide 3
Left Hemisphere
Typical Neuron
Grey Matter vs. White Matter
Neural Density in Cortex
148 000 neurons / sq. mm
Hence, about 15 million / sq. cm

Cortical Areas
Neural Representations
Macaque Visual System
Hierarchy of Macaque Visual Areas
Bat Auditory Cortex
Neurons
Typical Neuron
Dendritic Trees of Some Neurons
inferior olivary nucleus
granule cell of cerebellar cortex
small cell of reticular formation
small gelatinosa cell of spinal trigeminal nucleus
ovoid cell, nucleus of tractus solitarius
large cell of reticular formation
spindle-shaped cell, substantia gelatinosa of spinal chord
large cell of spinal trigeminal nucleus
putamen of lenticular nucleus
double pyramidal cell, AmmonŐs horn of hippocampal cortex
thalamic nucleus
globus pallidus of lenticular nucleus

Axonal Terminations
(Tectum of Turtle)
Axonal Net
Layers and Minicolumns
Slide 19
Neural Networks in Visual System of Frog
Frequency Coding
Variations in Spiking Behavior
Chemical Synapse
Action potential arrives at synapse
Ca ions enter cell
Vesicles move to membrane, release neurotransmitter
Transmitter crosses cleft, causes postsynaptic voltage change

Typical Receptor
Axon Hillock
Dendrite & Dendritic Branches
Dendrite & Dendritic Spine
Neuropil
Myelinated Axon Making Synapse on Dendrite
Various Synapses
Excitatory Synapse Between Axon Terminal and Dendritic Thorn
Dendro-dendritic Synapses
Electrotonic Synapse