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Topic E Stimulus and Response. Stimuli Stimulus- A distinguishable change in the internal or external environment Response- The reaction to a stimulus.

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Presentation on theme: "Topic E Stimulus and Response. Stimuli Stimulus- A distinguishable change in the internal or external environment Response- The reaction to a stimulus."— Presentation transcript:

1 Topic E Stimulus and Response

2 Stimuli Stimulus- A distinguishable change in the internal or external environment Response- The reaction to a stimulus Reflex- An innate behavior or reaction to a stimulus – A rapid unconscious autonomic response

3 Responses to Stimuli

4 Receptors Sensory receptors – Nerve ending that responds to a stimulus (internal or external) – Initiates sensory transduction By ACTION POTENTIALS

5 Neurons Sensory Neurons – Converts external stimuli of the environment into internal stimuli E.g. vision, touch, hearing… Relay Neurons – INTERNEURON ( part of CNS Central Nervous System) – Usually between sensory and motor – Can link up to the brain for controlled varied response Motor – Neuron that triggers physical response – By neurotransmitter

6 Synapses Special junctions used by neurons to pass signal molecules on to other neurons or receptor cells, such as muscles Allow neurons to form circuits from the CNS

7 Effector Effector cell- muscle, gland, or cell, capable of responding to a stimulus – At terminal end of an efferent neuron or motor neuron Effector molecule – Small regulatory molecule that binds to a protein, altering its activity

8 Reflexes Involuntary, fast, reaction to a stimulus

9 Pain Withdrawal Reflex Involuntary reaction to pain – Body can be trained to over-ride reflex – Unconscious, drugged, or drunk bodies will not exhibit reflex

10 Knee Jerk Reflex


12 Example The bird Sylvia atricapilla (blackcap) breeds during the summer in Germany 10% of blackcaps now migrate to the UK instead eggs were collected from parents who had migrated to the UK in the previous winter and from parents who had migrated to Spain Birds whose parents had migrated to the UK tended to fly west, wherever they had been reared, and birds whose parents had migrated to Spain tended to fly south- west.

13 Behavior is what an animal does and how it does it. What is Behavior?

14 Behavior Innate – Independent from environment Learned Develops as a result of experience

15 1.Kinesis: "change the speed of random movement in response to environmental stimulus“ 2.Taxis: "a directed movement toward or away from a stimulus; positive and negative taxes 3.Reflex: "movement of a body part in response to stimulus". 4.Fixed Action Pattern (FAP): "stereotyped and often complex series of movements, responses to a specific stimulus", hardwired, however, not purely genetic, may improve with experience a.programmed response to a stimulus b.stimulus of FAP = "releaser", sometimes called "sign stimulus“ c.examples: - courtship behavior - rhythms - daily (circadian); annual (circannual)

16 Learning - Learned Behavior: Five Categories A. Imprinting 1. a strong association learned during a specific developmental period a. "sensitive period" or "critical period" b. imprinting of baby geese on mother - Lorenz baby geese imprint on mother within hours of hatching will imprint on any object during that period 2. learning a releaser for an innate FAP

17 B. Habituation 1. decline in response to a harmless, repeated stimulus filter - prevents animal from wasting energy/attention on irrelevant stimuli adaptive

18 C. Conditioning - laboratory setting 1. classical conditioning animals make associations - Pavlov's dog associates bell with food, begins to salivate, can be extinguished and later followed by recovery (unconditioned stimulus - meat, unconditioned response - salivation, conditioned stimulus - bell, conditioned response - salivation) a.animal learns to perform an "old" response to a new stimulus b.Pavlov's dog - place dried meat powder in dog mouth - salivation - associate with bell - salivation to bell c.Stimulus first, behavior second (but of course there is an expectation of reward second)


20 2. operant conditioning a. perform behavior to receive reward or avoid punishment b. Skinner Box - levers, reward - self training elaborate protocols c. behavior first, reward second (but of course there is a stimulus, if only a thought of reward)

21 Innate Behaviors – inherited, instinctive A. programmed by genes; B. highly stereotyped (similar each time in many individuals) C. Four Categories 1.Kinesis 2.Taxis 3.Reflex 4.Fixed Action Pattern

22 D. Trial and Error Learning - nature setting 1. natural operant conditioning 2. modify responses to specific stimuli (releasers) - making both more adaptive 3. modify releaser to specific FAP - making both more adaptive Observational learning - social imitation

23 E. Insight, reasoning 1.manipulating concepts in the mind to arrive at adaptive behavior 2.mental trial-and-error 3.internal memory stores are used as additional sensory/information source All examples of tool-using: chickadees/tits and opening milk bottles Egyptian Vulture - uses rocks Cocos Finch - uses splinters of wood North American Gulls, Northwestern Crow - smash clams on sandy beaches

24 Cognition is the ability of an animal’s nervous system to perceive, store, process, and use information gathered by sensory receptors. The study of cognition connects nervous system function with behavior

25 Kinesis and taxis. –These are the simplest mechanisms of movement. Kinesis is a change in activity rate in response to a stimulus. –For example, sowbugs are more active in dry areas and less active in humid areas. Taxis is an automatic, oriented movement to or away from a stimulus. –For example, phototaxis, chemotaxis, and geotaxis. Animals use various cognitive mecha- nisms during movement through space Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

26 Taxis and Kinesis lecture DVs DVs Responses to stimuli Taxis is directional to or away Kinesis is random movement

27 How Learning Improves Survival Can prevent an animal from repeating dangerous behaviours Example: – Fox/wolf attempts to eat a porcupine – Gets pricked or poked – No longer attempts to eat porcupine

28 Songbird repertoires provide us with examples. –Why has natural selection favored a multi-song behavior? Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.5

29 It may be advantageous for males attracting females. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.6


31 Medulla Oblongata controls automatic and homeostatic activities, such as swallowing, digestion and vomiting, and breathing and heart activity.

32 Cerebellum: coordinates unconscious functions, such as movement and balance.

33 Hypothalamus: maintains homeostasis coordinates the nervous and endocrine systems, secreting hormones of the posterior pituitary, and releasing factors regulating the anterior pituitary.

34 Pituitary gland: the posterior lobe stores and releases hormones produced by the hypothalamus and the anterior lobe, and produces and secretes hormones regulating many body functions.

35 Cerebral hemispheres act as the integrating centre for high complex functions such as learning, memory and emotions.

36 Animal Experimentation On Brain Growth and Behavior – Rats placed on turntable had more mature brain cells in the vestibular area of the brain – Rats placed in a more stimulating environment had a larger cerebral cortex Also more “spines” which mostly serve as receivers in synaptic contacts

37 Sympathetic Control Sympathetic- Autonomic – Responsible for organs and glands (functioning unconsciously) Responsible for flight or fight response and homeostasis Used for actions requiring a quick/immediate response

38 Parasympathetic control responsible for stimulation of activities that occur when the body is at rest, including sexual arousal, salivation, lacrimation (tears), urination, digestion, and defection (pooping) – SLUDD Branches from the Autonomic system Functions in actions not requiring an immediate response

39 Pupil Reflex Controls the diameter of the iris when exposed to light Light stimulates photosensitive ganglion cell Synapses with the oculomotor nerve, which controls the muscle that constricts the pupil

40 Detecting brain death/damage Under normal conditions, the pupils of both eyes respond identically to a light stimulus, regardless of which eye is being stimulated a direct response in the right pupil without a consensual response in the left pupil suggests a problem with the motor connection to the left pupil Brain death is when a portion of the brain is no longer functional

41 Pain

42 Endorphins Prevent nerve cells from releasing more pain signals

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