Limbic & emotions 18 april 2016

Limbic system and

physiology of emotions

Dr Madanmohan. MD, DSc, FIA

Prof. & Head, Department of Physiology

Mahatma Gandhi Medical College & research

Institute

Limbus: border, ring.

Rim of cortical tissue around hilum

and associated subcortical structures.

Emotion: a strong feeling

Limbic

system

Learning objectives

1. Draw a schematic diagram of limbic system and

label its components.

2. Name areas of brain that are functionally

connected to limbic system via afferents and

efferents.

3. Draw schematic diagram of Papez circuit and

describe its significance.

4. Define the terms: emotion, instinct, behavior,

motivation.

5. State the functions of lymbic system.

6. Briefly describe the nature of emotions.

Limbic system

• Visceral brain /rhinencephalon

• Medial aspect, on top of neuraxis

• Advanced part of primitive brain

Allocortex: primitive brain, phylogenetically oldest

3 layers. Hippocampus.

Juxtallocortex: transitional, 3-6 layers.

Cingulate, insula.

Neocortex: highest developed, 6 layers.

Phylogenetically newest

Limbic

system

Limbic: components

Limbic cortex/lobe:

Orbito-frontal cortex.

Insular area.

Cingulate gyrus.

Hippocampal gyrus.

Uncus.

Parts of parietal

and temporal lobes.

Related areas:

Hypothalamus.

Ant. thalamus.

Midbrain RF.

Frontal cortex.

Amygdala.

Septal nucleus.

Limbic: connections

1. Intrinsic

2. Neocortex

3. Olfactory area

4. Thalamus (somatic)

5. Hypothalamus (visceral)

6. Midbrain RF

Papez circuit

Papez circuit

Prefrontal cortex

Cingulate gyrus

Ant. thal Hypothal

Mam. body

Functions

1. Integrates afferent impulses:olfactory, visceral, somatic.

2. Emotions: lesion/stimulation: rage, placidity, fearlessness.

3.Motivation: reward/punishment areas.

4. Feeding behavior: survival of individual..

5. Sexual behavior & mating: survival of species.

6. Endocrine functions

7. Recent memory

8. Circadian rhythms

9. Preservation of self and species

Instinct: innate behavior pattern

playing, eating, mating, parenting.

Motivation: to stimulate/inspire to action,

incentive.

Behavior: the way we conduct ourselves.

Emotion: the way we feel. A strong feeling.

Emotions: components

1. Cognition: awareness of sensation.

2. Affect: feeling.

3. Conation: urge to act.

4. Physiological

responses: BP, fh, GSR……..

Negative emotions: anger, rage, grief, fear,

lust, greed, jealousy, ego.

Positive emotions: love, compassion,

human values.

Replace negative emotions by positive ones *

Emotions: neurophysiological correlates

Rage & fighting: lateral hypothalamus.

Tranquility: ventromedial hypothalamus.

Sex drive: anterior & most posterior hypothal.

Reward area: median fore brain bundle.

Punishment area: central grey around aqueduct

of Sylvius.

Limbic system & emotions: applied

Stimulation experiments: amygdala: anger/rage.

Aggressive patients: amygdaloidectomy.

Damage : encephalitis (influenza), tumor,

brain or pituitary surgery.

Gonadal hormones : aggressive behavior.

Sex steroids in uterus.

Uncontrolled emotions : destructive

Suppressed emotions : stress

Emotional disorders:

We have needs & desires.

Expectations too.

Can neocortex “satisfy” limbic needs ?

Cortex is above limbic system.

Mind-body interactions & civilized behavior.

Emotional and / or rational?

• Can we change our emotions and behavior?

• Can neocortex (prefrontal lobe) control basic,

limbic, animal behavior?

Emotions, morbidity and mortality:

new perspectives from

psychoneuroimmunology

Kiecolt-Glaser et al. Ann Rev Psychol 2002; 53: 83-

107

Yoga for drug abuse

Benson H. N Engl J Med 1969; 281: 1133

Nature Nurture

(genes) (practice)

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