History of Biological Psychology

• Plato was the first to suggest that the mind was in the head.

• In the 1800’s, Franz Gall proposed phrenology - studying bumps on the head for character traits and suggesting different parts of the brain control different aspects of behavior.

Biological Psychology

Biological Psychology is the scientific study of links between biological and psychological processes.

Biological Psychology

• Our study begins with bottom up processing: processing that begins with the nerve cells and goes up to the brain.

• We will also look at top down processing: how our thinking and emotions affect our behavior.

Neuronsand

Neurotransmitters

Nervous System

An extensive network of specialized cells that carry information to and from all parts of the body.

Brain(CNS)

SpinalCord(CNS)Nerves

(PNS)

• Neuron (NEW-ron) – the basic cell that makes up the nervous

system and which receives and sends messages within that system.

• Neurotransmitters – Specialized chemicals that facilitate or

inhibit the transmission of impulses from one neuron to the next

The Neurons and the Neurotransmitters: The Structure of the Neuron

The Neurons and the Neurotransmitters: The Structure of the Neuron

• Most neurons are made of three parts:– cell body (soma)

• contains the nucleus • keeps the cell alive and functioning

– dendrites• receives signals from other neurons

– axon • slender, tail-like extension of the neuron • sprouts into branches, each ending in a

bulbous axon terminal

The Neurons and the Neurotransmitters: The Structure of the Neuron

• Other parts of the neuron– axon terminal

• Bulbous end of the axon where signals move from the axon of one neuron to the dendrites or cell body of another

– myelin • Fatty substances that coat the axons of

neurons to insulate, protect, and speed up the neural impulse.

• Insulates the neuron.• Bundles of myelin-coated axons travel

together in “cables” called nerves.

• Resting potential• Action potential

− Neuron fires an impulse

• Neurons generate chemical electricity− Positive & negative ions

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Neural Communication

• All-or-none - referring to the fact that a neuron either fires completely or does not fire at all.

• Return to resting potential.

LO 4.2 What are neurons, and how do they work?

The Neurons and the Neurotransmitters: Neural Communication

• After a neuron fires there is a Refractory Period – a period of inactivity after it has fired.

The Neurons and the Neurotransmitters: Neural Communication

The Neurons and the Neurotransmitters: Communication between Neurons

• Axon terminals are separated from the receiving neurons by fluid-filled gaps: synaptic gap (or cleft).

• Synapse – junction where axon terminal of sending

neuron communicates with receiving neuron

The Synapse

The neuron's electrical impulse reaches the synaptic knobs, triggering the release of the neuron's chemical messengers, called neurotransmitters, from the synaptic vesicles and into the cleft.

Neurotransmitters

• Chemical substances that transmit messages between neurons

• Released into synapse by axon terminals of sending neuron

• Bind to receptor sites on dendrites of receiving neuron

• Taken back into axon terminal by the process of reuptake

How Drugs and Other Chemicals Alter Neurotransmission

• Agonist = a molecule that, by binding to a receptor site, stimulates a response.

• Antagonists = a molecule that, by binding to a receptor site, inhibits or blocks a response.