Mammalian Physiology- Behaviour

Behaviour: An action that alters the relationship between an organism and its environment.

Behaviour may occur as a result of;

• an external stimulus (e.g. sight of predator)
• an internal stimulus (e.g. hunger)
• a mixture of both (e.g. mating)

Behaviour is largely controlled by genes. This is called Innate Behaviour.

Innate behaviour: A pattern of inherited, pre-set behaviour that does not require learning or practise. These behaviours are stereotyped and are inflexible and help adapt the animal to its environment.

Reflex actions: Rapid, autonomic responce to stimuli. (See reflex arc)

Animals can modify/refine stereotyped behaviour through experience

Pavlov's work on classical conditioning

• Ivan Pavlov- digestive activity in dogs
• Aim- to find the degree of salivation caused by different foods
• Made a hole in dogs mouth, tubed it so saliva flowed out. Dog not fed for a while, then meat powder blown through tube and saliva collected.
• Then a bell was rung before meat powder given and dog began to salivate upon the sound of the bell
• This kind of learning = classical conditioning
• Stimulus of taste/smell of food = unconditional stimulus
• Stimulus of bell ringing = conditional stimulus
• Whole reflex (responce to bell) = conditional reflex

Skinner's work on operant conditioning

• Involves a more complex process than salivation reflex, as dog is now making a decision about how and where to move = operant conditioning
• Uses a skinner box. A cage in which an animal can be placed containing a bar the animal can move. The animal eventually learns to associate pressing the bar with a reward.

Adaptive value of conditioning

• Both classical and operant can be described as associative learning
• The reward it gets is called a reinforcer
• Increases the chances of an animal's survival and reproductive success

Kohler's work on insight learning

• Chimpanzees, Sultan, banana with a stick
• Gave sultan 2 sticks which fit inside eachother to create a longer one. He eventually, after trial and error, worked out how to get the banana which was further away
• This is called insight learning- seemed as though the chimp had a moment of inspiration
• However, cannot be experimented on as cannot be repeated

Physiological basis of memory

• When the surface of the sea hare is touched, its gills retreat. However, if the gills are continually touched but nothing happens then the sea hare learns not to withdraw gills. This is because more and more AP's arrive at synapse in pre-synaptic membrane, thus less effect on Ca+ channels thus no transmitter is released, thus not enough to produce AP in post-synaptic membrane.

• The opposite is sensitisation. Before the dorsal surface is touched the sea hare is given a mild shock, thus it withdraws its gills quicker than usual. The synaptic connections are now strengthened.
• Short-term memory and long-term memory
• Damage to forebrain (hippocampus and thalamus) results in ability to form new memories
• Explicit memories = things we know we know (i.e. particular facts to recall and be tested on)
• Implicit memories = things we are not aware of (i.e. we had to learn but can now do without thinking, such as riding a bike)