Lecture 5 Flashcards
What does behaviour involve?
Behaviour involves a coordinated muscular response
Sensory system > Nervous system > Behaviour
Peripheral nervous system vs Central nervous system
Simple reflexes- PNS (peripheral) nerves ganglia outside of brain/spinal cord (connects CNS to limbs/organs)
Complex behaviours- CNS (central)
◼ Much more protected (spinal column/skull) so less damage
Often modulated by hormones
◼ Facilitate or inhibit a specific behaviour
What is an example of the Interaction of Physiology and Behaviour
High testosterone leads to increased aggression BUT Losing a fight decreases testosterone production
What are the differences between the Neural and sensory system and the hormonal and pheromonal system?
Neural and sensory systems
❑ electrical
❑ fast acting
❑ central (CNS) and peripheral (PNS)
Hormonal and pheromonal systems
❑ chemical
❑ longer acting ex. seasonal
❑ target specific tissues
The two systems are interconnected: Neural—> hormonal via hypothalamus
Pheromonal —> neural via sensory systems
Where is the hypothalamus?
in the Brain region adjacent to pituitary gland
What is the primary function of the
hypothalamus?
❑ Controls master gland (pituitary)- importance of these 2 organs
❑ 2 H’s homeostasis and hormones
◼ Senses what is wrong
❑ Produce releasing and inhibitory hormones
Brain region adjacent to pituitary gland
Secretes ‘releasing hormones’
◼ Ex. GHRH (growth hormone releasing hormone), CRH (corticotropin releasing hormone), GnRH (gonadotropin releasing hormone)
Causes release of pituitary hormones into
circulation -> act on target tissues
What are simple reflexes?
patellar, blink, swallow
What are Complex behaviours?
courtship, nesting, feeding
What are the properties of neural response?
Properties of neural response:
1. Initiation
2. Coordination
❑ Response Inhibition
3. Control
❑ Latency, refractory period,
homeostasis
What is initiation in the properties of neural response?
Stimulus internal or external
Threshold and Action Potential (Response) - Moving ions (sodium or potassium) depolarizes membrane potential, nerve gets excited and get a response
Summation – temporal or spatial- whether or not enough to cause action
Electrical activity of neurons
❑ Moving of ions to reach state where
membrane potential is depolarized to
initiate action potential
◼ Response to stimulus- neural
response must exceed threshold
to initiate an action potential
❑ ‘All or nothing’ response
What year was Neurophysiology discovered?
1906 by Sherrington
What is Summation?
Multiple inputs combine to initiate a response
What is Temporal summation?
Stimulus is repeated over time single neuron rapid-firing
What is Spatial summation?
Repeated at multiple site multiple neurons sending signals
What is inhibition and coordination in the properties of neural response?
Inhibition is necessary for coordination
◼ Neural inhibition
❑ Walking: opposing muscles are
inhibited
◼ Behavioural inhibition
❑ Can only do one thing at a time!
❑ Alternate bouts of feeding and
drinking
What is control in the properties of neural response?
Physiology and behaviour balance each other to maintain homeostasis
◼ Energy balance
❑ Input and output
❑ Growth and maintenance
What are models for homeostasis and what are examples?
◼ ‘Closed loop’ systems
◼ Feedback mechanisms- performing the behaviour results in inhibition (-)
Thermoregulation
◼ Cold: leads to huddling, shivering
◼ Heat: panting, wallowing, shade
seeking, drinking
Energy balance & hydration
◼ Hunger: hunting, foraging
◼ Thirst: Seek water, drink
2 important organs! - Hypothalamus and Pituitary
Do Hormones cause behaviour?
No, They initiate physiological actions which may be necessary for a behaviour
Release could cause another hormone to be released OR Release could directly cause an organ to change behaviour
Do hormones have dual action?
Yes, many hormones have dual action:
❑ Act as a neurotransmitter in nervous
system
❑ Act as hormones in circulatory system
What are pheromones?
Chemical that is released into the
environment which causes a specific behavioural or physiological reaction in member of same species
Pheromonal system affects hormones via sensory systems
❑ Two main roles-
◼ Signaling (eg estrous- female present)
◼ Priming (eg initiate ovulation cycle
What are examples of pheromones?
◼ Naked mole rat
❑ Pheromone suppresses
other females, turning off their cycle
so the male will only mate with her
◼ Synchronization of ovulation cycles (humans)
◼ Ram effect in sheep (initiates cycling by
introducing a ram)
What are the 5 main senses? are there any more?
Sight, hearing, touch, smell, taste
Yes depends on the animal
What is Umwelt?
German word meaning environment or surroundings, used to describe- “The individual sensory environment and behavioural capabilities of a species”
Animal perceptions vary greatly from human abilities - failure to understand this limits our understanding of animal behaviour
We cannot assume that animals perceive their environment as we do!
What is vison?
Vision- is a balance between light sensitivity and colour detection
Significant species differences
❑ Cones – bright light – color vision
❑ Rods – dim light – not responsive to
color
Balance depends on species behaviour and dependence on visual information
Nocturnal species
❑ one receptor type: see grey scale at
high resolution
Crepuscular species
❑ twilight
◼ 2 colours: blue-violet and green
Diurnal species
❑ Humans, birds: see full colour
What is the hearing range of humans, cats, dogs, elephants, and bats?
Humans 20 – 20,000
Cats 100 – 32,000
Dogs 40 – 46,000
Elephants 16 – 12,000
Bats 1000 – 150,000
Elephants: Low end- infrasonic
Bats: High end- ultrasonic
Elephant hearing
Elephants use infrasonic calls for
communication over long distances
❑ “Contact calls”- used to communicate
location
◼ 21 Hz calls; 4-5 sec in duration
◼ Sounds can travel multiple kilometers
What is Electroreception in fish?
using electrical current for Dark environments, Stunning prey, location, communication
Fish/amphibious since salt water is a good
conductor
What is Magnetoreception?
❑ Sense magnetic fields, Orientation using earth’s magnetic fields
How does it work?
❑ Possibly via magnetite crystals, or
vision?
❑ Chryptochrome in birds eyes?
What is it?
❑ Found in some bacteria, bees and migratory birds… and cows?
◼ Grazing cows orient predominantly
north-south (2008 study) We don’t
know where the receptors are
