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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Book 1

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.

Experimental Design

Emphasised: keep as SIMPLE as possible - see summary of basic principles.

Some of the points which cropped up were:-

  1. Progression from {general/vague question} => {more precise / limited question} => {question formulated in terms of independent (Vind) and dependent variables(Vdep) }.
  2. Operational definitions of Vind and Vdep .
  3. Recognition of potential confounding variables - ensure by experimental design to eliminate their effects.
  4. Within-subject design (if possible) always preferable to between-subjects design.
  5. Cannot eliminate order effects in within-S design, but can eliminate their influence by counterbalancing.
  6. Express the null (H0) and alternative/experimental (H1) hypotheses in terms of Vind and Vdep.
  7. 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).

Preview of Book 2

  1. Outline of vertebrate nervous system and examples of different neurons (nerve cells).
  2. 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.
  3. 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
  1. 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).
  2. 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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