BBB Tutorial TWO:
17 March 2001 Glasgow Caledonian University
In this tutorial we discussed three areas: (i) a look back at
Book 1, behaviour and evolution, (ii) basics
of experimental design and (iii) looking
ahead to Book 2, neurophysiology.
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Important point stressed that when you consider selection, evolution,
adaptation etc., DO NOT suggest that adaptations occur, or features
are selected "for the benefit of the species" - this
is nonsense.
Group selection is not a valid concept.
Generally natural selection acts on the individual organisms.
But there is also kin selection - altruism - helping relatives
to pass on shared genes, as outlined in document on Evolution & Adaptation.
Emphasised: keep as SIMPLE as possible - see summary of basic principles.
Some of the points which cropped up were:-
- Progression from {general/vague question} => {more precise
/ limited question} => {question formulated in terms of independent
(Vind) and dependent variables(Vdep) }.
- Operational definitions of Vind and Vdep
.
- Recognition of potential confounding variables - ensure by
experimental design to eliminate their effects.
- Within-subject design (if possible) always preferable to between-subjects
design.
- Cannot eliminate order effects in within-S design, but can
eliminate their influence by counterbalancing.
- Express the null (H0) and alternative/experimental
(H1) hypotheses in terms of Vind and Vdep.
- Statistical test (appropriate to the data generated by the
experiment) tells you the probability (p) of H0
being true. If p is very small (>0.05) then you can
reject H0 and therefore accept H1 (the only
other possibility because of the experimental design).
- Outline of vertebrate nervous system and examples of different
neurons (nerve cells).
- Neuron as an input-output "device" - dendrites to
receive input, cell body, axon to send signal, terminal bouton
as output to synapse. Suitable anatomical structure relating to
amount of synaptic input, position of cell, length of axon, etc.
- Basically three categories of neuron:
Type of neuron
| Input from
| Output to
|
sensory neuron
| sensory receptor
| neuron
|
inter-neuron
| neuron
| neuron
|
motor neuron
| neuron
| muscle
|
- Sensory and motor neurons largely in peripheral nervous system
(PNS), interneurons largely in central nervous system (CNS) -
with functional centres and links between areas in the brain (see diagram).
- Semipermeable properties of cell membrane (of all cells) exploited
in neuron. Membrane with different properties of different parts
of the nerve cell. Of functional importance to nervous transmission
(action potential - electrical signal) is relative concentrations
of ions (especially Na+, K+ and Cl-,
but also organic anions inside cell) and equilibrium between electrical
(potential) and concentration gradients across the membrane, effected
by diffusion processes.
Some revision material issued:
General questions relating to early
chapters of Book 2 and
an exercise about membrane potentials
and neuronal functioning
- to be followed up in the April tutorial.
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