1. Cognitive & Biopsychological
Perspectives
Structure & Functioning of Neuron
(Neuron 1)

2. Structure & Functioning of Neuron
To provide a basic understanding of:
• The structure of the neuron
• Transmission of the neural impulse along
the neuron

3. NERVOUS
SYSTEM
Central Nervous Peripheral Nervous
System (CNS) System (PNS)
Spinal Somatic System Autonomic Nervous
BRAIN Cord
(Motor & Sensory)
System (ANS)
Voluntary
Sympathetic
Parasympathetic

5. Side View

6. Structure of the
Neuron

7. Structure of Neuron

9. The Neuron
• Resting Potential
• Threshold
• Action Potential
• ‘All or none’ law

10. The Neuron
• Sodium ions (Na+)
• Potassium ions (K+)
• Chloride ions (CL-)
• (Also, Protein ions An-)

11. Resting Potential
Axon
- - - - - -
- - - - - - -

12. Distribution of Negative Ions
Axon
CL- CL- CL- CL-
An- CL- An- An-
An- An- CL-
CL- CL- CL- CL-
An- Trapped inside axon
CL- greater concentration outside axon than inside

13. Distribution of Positive Ions
Axon
Na+ Na+ Na+ Na+ K+
Na+ K+ K+ K+
K+ K+ Na+ K+ K+
Na+ Na+ K+ Na+ Na+
K+ greater concentration inside axon than outside
Na+ greater concentration outside axon than inside

14. Resting Potential
The resting potential is maintained by:
1. Selectively Permeable Membrane
2. Sodium – Potassium Pump

15. Resting Potential
Axon
Na+ Na+ Na+ Na+ K+
Na+ K+ K+ K+
K+ K+ Na+ K+ K+
Na+ Na+ K+ Na+ Na+
3 Sodium ions (Na+) pumped out for every 2 Potassium ions (K+)
drawn in

16. Propagation
Propagation of the action potential
refers to the transmission of the action
potential along the axon.

17. Propagation
Axon
+
+++ - - - - -
+++ - - - - - -
+

18. Propagation
Axon
- - +++ - - - -
- - - +++ - - -

19. Propagation
Axon
- - - - - +++
- - - - - - +++

20. Saltatory Conduction
Saltatory conduction is the
transmission of the impulse
from node to node

22. "All or None" law
If the threshold is reached the neuron
will 'fire' (ie a neural impulse will
occur) if it is not reached the neuron
will not fire
• Therefore, the size and shape of the
action potential are independent of
the intensity of the stimulus that
initiated it

23. Refractory Period
For a few milliseconds following a neural
impulse the membrane is temporarily
unexcitable and the axon cannot be fired
again regardless of the strength of the
stimulus.
This interval is known as the
Absolute Refractory period

24. Refractory Period
Following the Absolute Refractory period
• there is a short period of time just before
the membrane returns to normal during
which the neuron will fire but a stronger
than normal stimulus is required
• This period of time is called the
Relative Refractory period

25. Neuron Plasticity & Age
The structure of the neuron is fairly
‘plastic’, that is the fibres of the
neuron can increase or decrease their
branching pattern as a function of
age, experience and chemical
influences.

26. Dendritic Growth

27. Glia (Neuroglia)
• Glia are the other main component of
the nervous system besides neurons
• Occupy about the same total space as
neurons
• They do not transmit information

28. Glia
Functions
• Remove waste
• Fill space left by dead neurons (form
scar tissue)
• Build the myelin sheath
- Schwann cells (PNS)
- Oligodendrocytes (CNS)

29. Spinal Research
Raisman (1997)
• Olfactory cells from the nose (although
CNS cells) can regenerate and form
functional connections after damage

30. Spinal Research
Raisman (1997)
• Studies using Schwann sheath, found
although they provide guidance to a
regenerating spinal cord, the cord can
not make the connection at the other
end into the oligodendrocyte
• Olfactory cells were able to make that
connection.

32. EEG
Electroencephalograph (EEG)
Machine that records the electrical activity of the
brain via electrodes placed on the surface of the
scalp
Electroencephalogram (EEG)
Trace or record of the electrical activity of the
brain

34. Brain Waves

35. References
Carlson, N. (2010). Physiology of Behavior, (10th
ed). London: Allyn & Bacon.
Kalat, J. (2009). Biological Psychology, (10th ed).
Belmont, California: Wadsworth.
Pinel, J.P. (2008). Biopsychology, (7th ed).
London: Allyn & Bacon.