1.
Neural System
 The structural and functional unit of the neural system is neuron,which shares
certain similarities regardless of what message they conduct.
 The variation in the length and diameter of the axon is important because”
the speed of the nervous impulse affects the speed at which animal respond
behaviourally” and the thicker the diameter of an axon,the faster the norvous
impulse travels along it.[Dugatkin]
 It is the evolutionary and comparative approach to the study of animal
behaviour and it’s underlying mechanistic control by the nervous system.
Neuroethology
NEURAL CONTROL OF
ANIMAL BEHAVIOUR

2.
The Nervous Impulse
 In response to an stimulus (such as tactile),a wave of electrical activity
sweeps down along the axons of sensory nerve cells that are in contact with
the skin.
 Not all stimuli produces such a response.
 For this process to begin,the stimulus must exceed the nerve cell’s
“threshold”.
 Threshold is a function of the amount of change in the voltage across a
neuron‘s membrane,but what is important is that stimuli that don’t meet this
threshold fail to cause the nerve cell to fire,and stimuli above the threshold
always cause the nerve cell to fire.
 Conduction of impulses occurs via an electrical impulse jumping across the
synaptic gap between neurons or,more commonly,the release of a
neurotransmitter- for example, acetylcholine.

3.
Reflexes and behaviour
 In all vertebrates,the spinal cord has two main functions, integration of reflex
actions and conduction of nerve impulses to and from the brain,establishing
connection between peripheral and central nervous system.
 A reflex arc is the simplest but complete functional unit of the nervous
system capable of detecting changes and causing a response.

4.
Mammalian brain has three primary vesicles and five secondary vesicles
which gives rise to different parts of the brain.
Embryonic vesicle Embryonic vesicle Main components in
adults
Early Embryo Late Embryo
Forebrain
(Prosencephalon)
Telencephalon
Diencephalon
Cerebrum
Thalamus
Hypothalamus
Midbrain
(Mesencephalon)
Mesencephalon
Metencephalon
Optic lobes (tectum
midbrain nuclei)
Cerebellum
Pons
Hindbrain
(Rhombencephalon)
Myelencephalon Medulla oblongata

5.
Different areas of brain and functions
controlled by them.
Area Controlled functions
OCCIPITAL LOBE Ability to recognise objects, vision.
TEMPORAL LOBE Hearing, Memory, Meaning and Language.
PARIETAL LOBE Senses such as touch,pain,taste, pressure and
temperature.
Also have language function.
FRONTAL LOBE Emotions, reasoning, planning, movements and parts of
speech.
Also involved in purposeful acts such as creativity,
judgement and problem solving.

6.
Area Controlled functions
CEREBELLUM Movement,balance,posture and coordination.
Also in thinking, novelty and emotions.
HYPOTHALAMUS Body temperature, emotions,hunger,thirst, appetite,
digestion and sleep.
THALAMUS Control of sensory integration and motor integration.
PITUITARY GLAND Control of hormone and it helps to conversion of food
into energy.
PINEAL GLAND Controls growth and maturity.
AMYGDALA Emotions (happy or sad)

7.
Area Controlled functions
CEREBRAL CORTEX Thinking, voluntary movements, languages, reasoning
and perception.
MID BRAIN Controls breathing reflexes and swallowing reflexes.
PONS Motor control and sensory analysis.
MEDULLA OBLONGATA Breathing.
HIPPOCAMPUS Forms and stores memories.

8.
Different areas of brain and functions controlled by
them

9.
How Neuron Controls Behaviour
 The neuroloical control of behaviour is among the most exciting topics in modern
biology and much research in this field has traditionally utilizes a small number of
well known hemimetabolous insect models.
 Marie et al.(2000),focused on developmental neuroplasticity in Periplaneta.
Neuroplasticity – It is the ability of the brain to change continuously
throughout an individual’s life.
 Most recent work by Ma et al.(2011), targeted the dopamine synthesis pathway in
Locusta migratoria,in an attempt to nuravel the importance of neurotransmitter in
locust swarming behaviour.
 A more widely studied process concerned with neuronal restructuring and
development is that of learning and formation of both long and short term
memory. Nitric Oxide (NO),plays a role in the development of long term
memory,by directing synapse growth via the well characterized protein kinase A
and CREB- mediated pathway.

10.
Some evidences showing the behavioural
control by neuronal system.
1. Complex response to simple stimuli.
 Male Centris pallida (bee),grasped the workers’thumb as if he were holding a
female of his species.Even though the thumb has only a slight similarity,at
best,to a female Centris pallida ,some males made repeated attempts to
copulate with it before giving up and flying away.
 Then it was evident that the bee’s nervous system was designed with some
special operating rules.
 Several experiments were done by Tinbergen and Lorenz that describes many
cases in which animals responded with an elaborate behaviour pattern to
stimuli that barely resembled the naturally occurring object that normally
triggers the behaviour.

11.
2. Neural Control of Instinct Behaviour
 A classic study by Tinbergen on begging behaviour of newly hatched herring
gull chicks shows the neural control of Instinct Behaviour.
 In his study he knew that begging gull chicks peck at the red dot towards the
end of their parents bill, which causes the adult to regurgitate a half-digested
fish or some other mouth-watering morsal for its offspring.
But he found that two-dimensional cardboard models of gull heads, and even
pointed sticks with bands on the end,also stimulated begging behaviour in
newborn herring gulls.
From this experiment, Tinbergen deduced that when a young gull looks at its
parent’s beak,it attends to a few simple cues, which activate sensory signals that
are relayed to its brain.Within the brain,other neurons generate a set of motor
commands that cause the chick to peck at the effective stimulus – whether it is
located on its mother’s beak or piece of cardboard.

12.
Instinct Behaviour in gull chicks

13.
3. Neural control in survival among Moths
 The classic work of Kenneth Roeder on the ability of night-flying moths to
evade predatory bats.
 Moths are attracted by the light.When a bat tries to chase a moth, sometimes
a moth turn abruptly or dive straight down just before a bat shows up,
evidence that at least some moths are able to detect and avoid these
predators.
 Acoustical signals triggers the turning or diving behaviour of moth.The moths
are also capable of detecting ultrasonic vocalisation with sound frequencies
between 20 and 80 kHz produced by bats.

14.
4. Control of escape behaviour in Tritonia Sea slugs
 When a Tritonia comes into contact with a releaser-chemicals associated with
the body of a predatory sea-star, the slug begins to swim,in the ungainly
fashion of sea slugs by bending its body up and down.If all goes well, it will
move far anough away from the sea star to live another day.
 This multistep escape response requires two to twenty alternative bends.The
slug bends its body through alternating contractions of its dorsal and ventral
muscles.These two sheets of muscles are regulated by two large motor
cells,the dorsal flexure neuron(DFN) and the ventral flexion neuron(VFN),
which fire in alternating sequence.
 This pattern of alternating contractions of its dorsal and ventral muscles was
explained by two scientists separately,Dennis Willows and P.A.Getting.
 Both gave a model to regarding its neuronal control of behavioural pattern.

15.
5. Neural control of Honeybee foraging.
 Honeybee foragers must navigate outside their hives or nest in search of foods,and
the ability to remember and retrieve information from the environment is critical.
 In invertebrates, the spatial navigation is most often linked with a cluster of small
neurons located at the front of the brain.
 This cluster, known technically as the Corpora pedunculata, is often referred to as
the Mushroom bodies, (Capaldi et al.,1999; Fahrbach,2006;).
 It plays a central role in spatial navigation and foraging behaviour in honeybee
(Visscher and Seeley,1982).
 When to hey first leave their home hive, rather than immediately beginning a
search for food in the nearby environment, would be foragers often turn back
towards the nest and hover up and down for several minutes, in what is referred
to as an Orientation flight orienting the foragers to the relative positions of their
hive in the environment (Willmer and Stone,).
 This study was later carried out by Withers and his team and they suggested that
‘activities related to foraging triggers a series of neural based changes in the
Mushroom body volume’ illustrating yet another instance of neural plasticity,
(Digger et al.,1997; Withers et al.,1993).

16.
Other examples of neural control in
behaviour.
1. Vocalization in plain din Midshipman fish.
2. Sleep and predation in Mallard duck.
3. Complex code breaking by a wasp.
4. Cortical magnification in the Tactile mode.
5. Circadian rhythm in cricket calling behavior, etc.