2.3 The Brain and Behaviour
This trail mainly follows the outlay of Russel
Conduit's lectures at La Trobe
University, Autumn 2001. His lectures are also one of the main sources
for this material.
Behavioural Neuroscience draws upon the insights of both psychology and
biology, with a strong focus on the biological aspect. When we respond
to stimuli, what does actually happen in the brain?
To a certain extent, a behavioural neuroscientist is a biological reductionist.
He believes that all behaviour can be reduced to biological processes;
that the brain is the basis of behaviour, and that there is no "mind",
only the brain.
188.8.131.52 Studying the brain
There are three main ways of studying the brain:
When doing an autopsy, you study the structure of the brain, not the
2. Lesion Studies
When doing lesion studies, you study a brain that has been damaged, and
the functional effects of this damage. But beware, this method does not
necessarily pinpoint the localization of a brain function, because the
part that was damaged may be only a neural circuit (a link) of the function
or functions which seem to be affected.
3. Brain Imaging: EEG, MRI, PET
2.3.1 Cell Biology
2.3.2 Neurons and Glia
2.3.3 Neural Communication
Main source: Nolte
To communicate, neurons use electrical signals. The currents is not carried
by electrons, but by movement of ions. Neurons are bounded by a semipermeable
membrane that is electrically polarized to a resting membrane potential
of typically -65 mV. To communicate, neurons use two different mechanisms:
(1) passively propagated potentials (in the dendrites)-- graded, relatively
slow, local potential changes (e.g. synaptic potentials, receptor potentials).
These can be summed (temporal summation and spatial summation).
(2) actively propagated potentials (action potentials) (in the axons)
-- for sending information over long distances
184.108.40.206 Neural Membrane
The neural membrane is a lipid bilayer.
220.127.116.11 Action Potential
18.104.22.168 Synaptic Transmission
2.3.4 The nervous system on a large scale
Main source: Rosenzweig
On a large scale, the nervous system consists of central
and peripheral divisions.
22.214.171.124 The 3 components of the peripheral nervous
1) The cranial nerves
these are connected directly to the brain, and are mainly concerned
with sensory and motor
2) The spinal nerves
these are connected at regular intervals to the spinal cord
3) The autonomic nervous system
the a.n.s. originates both from the brain and the spinal cord
1. The 12 pairs of cranial nerves
I. Olfactory -- Smell.
II. Optic -- Vision.
III. Oculomotor -- All eye muscles except
superior oblique and lateral rectus.
IV. Trochlear -- Superior oblique muscle.
V. Trigeminal -- Face, sinuses, teeth.
VI. Abducens -- Lateral rectus muscle.
-- Tongue, soft palate.
Facial muscles, salivary glands, tear glands.
-- Inner ear.
IX. Glossopharyngeal -- Posterior tongue, tonsils, pharynx,
pharyngeal muscles. Same.
X. Vagus -- Heart,
lungs, gastrointestinal tract, bronchi, trachea, larynx.
XI. Spinal accessory --
Sternomastoid and trapezius muscle.
XII. Hypoglossal -- Tongue muscles.
2. The spinal nerves
3. The autonomic nervous system
The autonomic nervous system is divided into two components: the sympathetic
nervous system and the parasympathetic nervous system.
126.96.36.199 The central nervous system
The c.n.s. consists of brain and spinal cord
188.8.131.52.1 The brain
184.108.40.206.2 The spinal cord