2. • Aristotle: People are THINKING
ANIMAL.What makes peoplr special
History
is they can overcome their brutish
emotions.
• Rousseau: Emotiuons are what
makes people special and gives us
reason for living.
• Hippocrates: Brain is the site of
emotion
3. Introduction • The word emotion is derived from
the latin word emovere which means
to stir up to get agitated
• Complex feeling state with psychic,
somatic, autonomic and behavioral
components.
4. • Emotion has two components:
– Mental
– Physical
• Mental component:
– Cognition- Awareness of sensation and it’s
cause.
– Affect- The feeling itself.
– Conation- urge to take action.
5. Oh it’s a roar. The
roar seems to be
that of lion
(Cognition)
I feel
frightened
Roaring of lion
(stimulus) (Affect)
Must run to
safety
(conation)
6. • Physical components:
– Changes in viscera and skeletal muscle
– Coordinated activity of autonomic and
somatic nervous system
– Example: tachycardia, tachypnoea,
cutaneous vasoconstriction etc in fear
7. Theories of emotion
• James-Lang theory
• Cannon-Bard theory
• Schachter-Singer theory.
• Current Theory
8. James lange theory
• Developed independently by Williams
James and Carl Lange in 1884
• According to the theory an emotional
event causes response in ANS. This
response is detected by CNS to produce
an emotional experience.
• Different emotional stimuli produces
different bodily response and lead to
different emotions
10. Cannon-Bard Theory • Walter Cannon and Phillip Bard – 1927
• The physiological reaction and the emotion
are assumed to occur at the same time.
• Emotional stimuli simultaneously produce a
response in the ANS and in the cerebral
cortex.
• The emotional experience is the
combination of these two system.
11. Cannon-Bard Theory • The influence of the cerebral cortex in
controlling emotion is show in the
phenomenon of Sham rage.
• When animals have their cortex
removed they go in extreme rages at
the slightest provocation.
• The response is often unrelated to
provocation and is short lived
13. theory
Schachter-Singer
• Also called cognitive arousal theory.
• A two-stage theory stating that for an
emotion to occur, there must be (1)
physiological arousal and (2) an
explanation for the arousal.
• Emotions are produced when autonomic
arousal is noticed by the person. He/She
tries to come up with an explanation for
the arousal and depending on the
explanation, label their emotion.
15. Current Theory • No single neural system produces emotions
• Different emotions may depend on
different neural circuits, but many of these
circuits converge in the same parts of the
brain
• The limbic system may be involved in some
emotional experiences, but it is not the sole
neural system underlying emotion
• Feelings (emotion) result from the interplay
between:
– The amygdala, hypothalamus, brain stem &
autonomic nervous system.
16. Limbic system • Limbus means a ring
• Limbic system part of cortical and
subcortical structure forming a ring around
brainstem.
• The French physician Paul Broca first called
this part of the brain "le grand lobe
limbique" in 1878.
• Formerly called rhinencephalon.
• The components of the limbic system
located in the cerebral cortex have fewer
layers than the classical 6-layered
neocortex, and are classified as allocortex
or archicortex.
17. Limbic system • Consist of limbic lobe and related
subcortical nuclei.
• Limbic lobe includes
– Cingulate gyrus
– Isthmus
– Hippocampal gyrus
– Uncus
• Subcortical nuclei include
– Amygdala
– Septal nuclei
– Hypothalamus
– Anterior thalamic nuclei
21. • Described by James Papez in 1937.
Papez circuit
• Papez Proposed that there is an
emotion system that links the cortex to
the hypothalamus.
• Discovered the circuit after injecting
rabies virus into a cat's hippocampus
and monitoring its progression through
the brain.
• One of the major pathways of the limbic
system and is chiefly involved in the
cortical control of emotion.
22. Papez circuit
• The original circuit proposed by Papez is shown by thick lines and more
recent connections as proposed by Paul D. MacLean are shown by thin line
23. • Buried within the anterior-inferior
temporal lobe.
Amygdala
• Essential in the control of love,
friendliness, affection, fear, rage,
aggression
27. Amygdala nuclei • Medial nucleus: Sensory input,
especially odour, relayed to
forebrain and hypothalamus
• Central nucleus: Sensory input via
cortex and thalamus, relayed to
hypothalamus and brainstem nuclei
• Basal nucleus: Sensory input relayed
to rest of amygdala and to PAG
28. Central nucleus • Plays the major role in emotional
response patterns
• Affects hypothalamus and both branches
of ANS: Increased HR and BP; ulcers,
urination, and defecation
• Affects brainstem nuclei to increase
arousal (VTA), vigilance (LC), cortex
activation (DLTN and nucleus basalis) and
startle (pons)
• Destruction of central nucleus limits
emotional response patterns.
• Electrical stimulation of central nucleus
triggers fear, agitation, stress illness
30. Amygdala lesion • Reduced ability to identify motivational and
emotional significance of events
• Electrical stimulation of amygdala can lead
to emotional attacks (rage)
Kluver-Bucy Syndrome:
• Results from bilateral removal of the amygdala and
inferior temporal cortex. Includes:
– loss of fear
– Indiscriminate dietary behaviour
– Greatly increased autoerotic sexual activity
– Tendency to attend to every visual stimulus
– Tendency to examine all objects by mouth
– Visual agnosia (cannot recognize objects visually)
– Inability to recognize facial expression
31. Effect of emotion Autonomic nervous system
• In threatening situation sympathetic
nervous system releases norepinephrine
that causes
– Palm sweating
– Increased heart rate
– Focused attention
– Greater skin conductance
Immune system
• Depressive disorders are associated with
decreased lymphocyte production
32. Effects of emotion Endocrine disturbances
• HPA activity: elevated in stress
increased in depression
• Thyroid axis activity: In depression both
hypothyroidism (5-10%) & hyperthyroidism
(20-30%) found.
Growth hormone:
• NE and dopamine stimulates growth hormone
secretion whereas somatostatin inhibits it.
• Decreased csf somatostatins are found in
depression, increased level is seen in mania
33. Physiology of special emotion Fear
• Site: The hypothalamus and amygdaloid
nuclei
• Effects of lesion: After destruction of
amygdala the fear reaction and its
autonomic and endocrine manifestation are
absent.eg monkeys are normally terrified of
snakes but after bilateral lobectomy they
approach snake pick them n eat them
• In humans amygdala damage causes
deficient fear response to visual and
auditory stimulus
34. The classical and curious case of
Phineus Gage.
• Phineas P. Gage (July 9, 1823 – May 21,
1860) was an American railroad construction
foreman now remembered for his
improbable survival of an accident in which a
large iron rod was driven completely through
his head, destroying much of his brain's left
frontal lobe.
• The damage to Gage’s frontal cortex had
resulted in a complete loss of social
inhibitions, which often led to inappropriate
behaviour. In effect, the tamping iron had
performed a frontal lobotomy on Gage, but
the exact nature of the damage incurred to
his brain has been a subject of debate ever
since the accident occurred.
35. Physiology of special emotion Anxiety: It is normal emotion in
appropriate situation but excessive
anxiety & anxiety in inappropriate
situation is disabling.
• Site: associated with bilateral increase in
blood flow in discreet portion of
anterior end of each temporal lobe.
• Facts: Anxiety is relieved by
benzodiazepine which binds to GABA
receptors and increase conductance of
these ion channels.
36. Physiology of special emotion Rage and placidity:
– Rage- extreme form of anger
– Placidity- Calm and peaceful
• Site: Neocortex, ventromedial
hypothalamic nuclei
• Facts: Human maintains a balance
between rage and placidity. Major
irritation make normal individual loose
temper but minor stimuli are ignored.
37. Motivation
• Motivation literally means that
which moves the will.
• It is a factor in most of the
behaviour.
• Factors that are responsible for goal
direction of a behaviour are the
motivation for that behaviour.
38. Reward and punishment Rewards:
• Things that an individual work for
• They make the behaviours leading to
them more often to occur.
Punishments:
• Opposite of rewards
• Associated with avoidance leading to
behaviour where an individual tries to
escape a painful situation.
39. Reward and punishment Neural mechanism involved:
• The neural mechanism of motivation has
ben obtained by studying the effect of brain
self stimulation.
• An unanaesthetised animal (rat) regulates
the rate at which electrical stimuli are
delivered through electrode implanted in
defined area of limbic system.
40. Reward and punishment • The brain area where stimulation leads
to repeated bar pressing are located in:
– The medial fore brain bundle
– Midbrain tegmentum
– Nucleus accumbens
– Dorsal brain stem
– Ventral tegmental area
• Stimulation of these sites produce
pleasurable sensation like relief of
tension, relaxed feelings
41. Reward and punishment
• The brain area where stimulation is
avoided are:
– Lateral portion of posterior hypothalamus
– Dorsal midbrain
– Entrorhinal cortex
• Stimulation of these sites produces
sensation ranging from vague fear to
terror
42. in reward system
Neurotransmitter involved
• The catecholamines (dopamine and
norepinephrine), morphine, enkephalin
are involved in the pathways mediating
reward system.
• Drugs that increase the self stimulation
are:
– Amphetamine- cause increase release of
dopamine
– Cocaine- binds and inhibit dopamine
transporter-dopamine uptake is reduced-
extracellular dopamine level is increased.
43. in reward system
Neurotransmitter involved • Drugs that block postsynaptic D3
dopaminergic receptors such as
chlorpromazine hydrochloride lower
activity in catecholamine pathways
and decrease self stimulation.
45. Physiology of addiction • A kind of dependence which manifests as:
– compulsive non-medical use of a substance
– loss of control over its use despite negative
consequences
• Despite many differences, virtually all
substances with the potential for addiction
affect dopamine levels in the pleasure /
reward pathway of the brain.
