9.1 - Neuroscience and Behavior History of the Mind...

Neuroscience and Behavior
History of the Mind:
Phrenology - In 1800, Franz Gall suggested that bumps of the skull represented mental abilities.
His theory, though incorrect, nevertheless proposed different mental abilities were modular.
Neural Communication:
The body’s information system is built from billions of interconnected cells called neurons .
Neuron - a nerve cell or a neuron consists of many different parts.
Dendrite - responsible for receiving messages from other neurons (feelers)
Axon - passes the message on to the next neuron (extends away from the cell body)
Myelin Sheath - cylindrical cover over the axon that helps speed up the delivery of the message
Action Potential - it is a neural impulse. A brief electrical charge that travels down an axon
generated by the movement positively charged atoms in and out of channels in the axon’s
membrane.
Action Potential Properties:
All or None Response: When depolarizing current exceeds the threshold a neuron will fire, and
below threshold it will not.
Intensity of an action potential remains the same, throughout the length of the axon.
Synapse: a junction between the axon tip of the sending neuron and the dendrite or cell body of
the receiving neuron. This tiny gap is called the synaptic gap , or synaptic cleft .
Neurotransmitters: chemical transmitters released from the sending neuron, travel across the
synapse and bind to the receptor sites on the receiving neuron, thereby influencing it to generate
an action potential.