The document discusses the structure and function of the brain and limbic system, and abnormal neurotransmission as it relates to psychopathology of mental disorders. It provides details on the central nervous system including the forebrain structures of thalamus, hypothalamus and limbic system. It also describes the peripheral nervous system, neurons, neurotransmission, neurotransmitters, hormones and their implications for mental illnesses. Key points are made about neurotransmitters like serotonin, dopamine and GABA being important in conceptualizing disorders like depression, schizophrenia and anxiety respectively.

1. Psychopathology of mental
disorders Review of
structure & functions of
brain, limbic system &
abnormal
neurotransmission
By:
Tejal D. Virola
M.Sc. Nursing (MHN)

2. Learning Objectives
• Discuss structure & function of brain and
limbic system
• Explain abnormal neurotransmission
• Describe psychopathology of mental disorders

3. Psychopathology of mental
disorders
• Psychopathology: Brach of psychiatry
which deals with the study of
manifestations of behaviour and
experiences indicative of mental illness
• Four D’s defining abnormalities:
• Deviance
• Distress
• Dysfunction
• Danger

4. Nervous System

6. Central Nervous System
• Central nervous system (CNS) consists
of brain and the spinal cord, which
act as the integrating and command
centres of the nervous system.

8. Forebrain
• Its important structures are thalamus,
hypothalamus, limbic system and the
cerebrum.
• All sensory impulses pass through
from thalamus to the higher centers,
therefore it is usually known as the relay
station.
• The thalamus has some control over the
autonomic nervous system and also plays a
role in the control of sleep and alertness

9. • Hypothalamus lies below the
thalamus.
• It exerts a key influence on all kind of
emotional as well as motivational
behavior.
• Centers in the hypothalamus have
control over the important body
processes like eating, drinking,
sleeping, temperature control and
sex.
• It also has control over the activities
of pituitary gland.

10. • Limbic system consists of structures in
the thalamus, hypothalamus and
cerebrum, which form a ring around the
lower part of the forebrain.
• Major structures within this system
include the olfactory bulb, septal nuclei,
hippocampus, amygdala and cingulate
gyrus of the cerebral cortex.
• The limbic system often called the
emotional brain, functions in emotional
aspects of behaviour related to survival,
memory, smell, pleasure and pain, rage
and aggression, affection, sexual desire
etc.

11. • Cerebrum is the most complex and
largest part of the brain.
• The cerebrum is covered by a thick
layer of tightly packed neurons called
the cerebral cortex.
• It is divided into two hemispheres; the
left and right hemispheres.

12. Right and Left
Hemispheres,
Association
Cortex

13. • Right and Left Hemispheres,
Association Cortex
• Cerebral cortex is responsible for many
higher order functions like language
and information processing.
• The cerebral cortex is divided into
sensory, motor and association areas

15. • Sensory area receives sensory input.
• Motor area controls movement of muscles.
• Association area is involved with more
complex functions such as writing.
• Each cerebral hemisphere is divided into four
lobes; frontal, parietal, occipital and
temporal lobes. The different parts of the
cerebrum are connected with different
mental functions. The visual area lying in the
occipital lobe is connected with the visual
organs or eye through the optic nerve. It is
the seat of visual sensations.

16. • The auditory area lies in the temporal lobe
and is connected with the auditory organs or
ears through the auditory nerves.
• It is the seat of auditory sensations and also
involved in memory.
• The parietal lobe lies in the upper rear
portion of the brain and is connected with
the information about special relationship
and structure.
• Frontal lobes contain several parts and are
concerned with organizing and planning our
actions, learning new tasks, generating
motivation and regulation of behaviour.

17. Right or Left
Brain
exercise

18. Try this!!!!
Read aloud, as quickly as possible,
the colour in which the words are written
but not the actual words.
GREEN YELLOW BLUE ORANGE
WHITE RED GREEN BLUE ORANGE
YELLOW WHITE GREEN RED BLUE
WHITE GREEN ORANGE YELLOW
ORANGE BLUE GREEN RED WHITE
YELLOW RED BLUE YELLOW
ORANGE RED WHITE BROWN WHITE

19. Midbrain
• Midbrain is concerned with the relaying of
messages particularly those related to
hearing and sight to higher brain centres.
One of its important structures is known as
reticular activating system (RAS).
• With the help of this structure an individual
is able to decide as to which impulses should
be registered consciously and, which should
be rejected.

20. Hindbrain
• Hindbrain is
composed of
three
structures the
medulla, pons
and
cerebellum.

21. • ‘Medulla’ controls breathing and many
important reflexes, such as those that
help us to maintain our upright
postures.
• It also regulates the highly complex
processes like digestion, respiration
and circulation.

22. • The ‘pons’ assist in breathing,
transmitting impulses from the
cerebellum to the higher brain regions
and in coordinating the activities of
both sides of the brain.
• ‘Cerebellum’ is responsible for body
balance and the coordination of body
movements like dancing, typing,
playing, etc.

23. Spinal Cord
• Spinal cord works as a
channel of communication
from and to the brain.
• It is a rope-like structure,
made up of long round nerve
fibers.
• It also works as an organ for
effective reflex actions like
withdrawal of the hand when
something is hot.
• These reflex actions are
almost automatic in nature.

24. Peripheral Nervous System
• Nerve tissues lying
outside the bony
case of the CNS
come in the region
of the peripheral
nervous system.

25. • It consists of a network of nerves,
which helps in passing the sense
impressions to the CNS as well as in
conveying the orders of the CNS to
the muscles.
• This peripheral nervous system is
subdivided into two parts, the somatic
system and the autonomic system.

26. • The somatic system is both a sensory
and a motor system.
• The autonomic system is only a motor
system consisting of two divisions, the
sympathetic and parasympathetic
system.
• The sympathetic system is connected to
the spinal cord and carries messages to
the muscles and glands particularly in
stress situations to prepare for an
emergency.

27. • The parasympathetic system is connected to
the brain and to the lower portion of the
spinal cord. It tends to be active when we are
calm and relaxed.
• The messages conveyed by the nerve fibres of
this system direct the organs to do just the
opposite of what the sympathetic system had
done.
• It directs the body organs to return to the
normal state after the emergency has passed.
• The sympathetic and parasympathetic
divisions of the autonomic nervous system
work in close co-ordination for maintaining
the equilibrium of the body function.

28. Brain &
behaviour

29. • How we will behave in a particular
situation depends upon the judgment of
our brain.
• The sense impressions, which are
received through the sense organs, do
not bear any significance unless they are
given a meaning by the nervous system.
• Learning also to a great extent is
controlled by the nervous system.
• The proper growth and development of
nerve tissues and nervous system as a
whole helps in the task of proper
intellectual development.

30. • Any defect in the spinal cord or the brain
seriously affects the intellectual growth.
• The emotional behaviour is also influenced
by the nervous system, especially at the
time of anger, fear and other emotional
changes.
• The process of growth and development is
also directly and indirectly controlled by
the functioning of the nervous system.
• The personality of an individual is greatly
influenced through the mechanism of the
nervous system.

31. Nature of
Behaviour of an
Organism,
Integrated
Responses

33. • The cerebral cortex has primary
areas, which control the incoming
sensory stimuli and the outgoing
motor responses.
• An individual is able to adjust
himself effectively to the
environment, because the various
nerve impulses are systematically
integrated by the brain.

34. • There are millions of nerve fibers,
which connect the various neurons of
the brain. The connecting nerve fibers
are known as ‘associate fibers’.
• The associate fibers are the
foundations of memory, language,
reasoning and other higher mental
processes.

35. Neuron

36. • A nerve cell with all its branches is called a
neuron. These are the basic elements of the
nervous system.
• A neuron has a nucleus, a cell body and a
cell membrane to enclose the whole cell.
There are tiny fibers extending out from
the cell body called ‘dendrites’.
• Their role is to receive messages through
electrical impulses from the sense organs
or adjacent neurons and carry them to
the cell body.

37. • The messages from the cell body further
travel the length of a nerve fiber known
as the axon.
• A group of axons, bundled together like
parallel wires in an electrical cable, is
referred to as a nerve.
• The axon (but certainly not all of them)
is surrounded by a fatty covering called
the ‘myelin sheath’. It serves to increase
the velocity, with which the electrical
impulses travel through the axons.

40. Neural impulses
Neurons are the
receivers and
transmitters of
messages. These
messages are
always in the
form of
electrochemical
impulses.

41. Synapse
• Information is
transmitted through
the body from one
neuron to another. The
junction between two
neurons is called a
synapse.
• The small space
between the axon
terminals of one
neuron and the cell
body or dendrites of
another is called the
synaptic cleft.

42. • Neurons conducting impulses toward
the synapse are called presynaptic
neurons and those conducting
impulses away are called
postsynaptic neurons.
• A chemical, called a
neurotransmitter is stored in the
axon terminals of the presynaptic
neuron. An electrical impulse
through the neuron causes the
release of this neurotransmitter into
the synaptic cleft.

43. Neurotransmitters
• Neurotransmitters play an essential function
in the role of human emotion and behaviour.
These are chemicals that convey information
across synaptic cleft to neighbouring target
cells.
• They are stored in small vesicles in the axon
terminals of neurons.
• When electrical impulse reaches this point,
the neurotransmitters are released from the
vesicles.

44. • They cross the synaptic cleft and bind
with receptor sites on the cell body of
dendrites of the adjacent neuron to
allow the impulse to continue its
course or to prevent the impulse from
continuing.
• After the neurotransmitter has
performed its function in the synapse,
it either returns to the vesicles to be
stored and used again or it is
inactivated and dissolved by enzymes.

45. • The process of being stored
for reuse is called reuptake.
• Deficiency or an excess of a
neurotransmitter can
produce severe behavioural
disorders.

47. Neurotransmitters function and
implications for mental illness
Neurotransmitter Function
Implications for
mental illness
I. Cholinergics
a. Acetylcholine Sleep, arousal,
pain perception,
movement,
memory
Decreased levels:
Alzheimer’s disease
Increased levels:
Depression
II. Monoamines
a. Norepinephrine Mood, cognition,
perception,
locomotion,
cardiovascular
functioning,
sleep & arousal
Decreased levels:
Depression
Increased levels:
Mania, Anxiety states,
schizophrenia

48. Neurotrans
mitter
Function
Implications for
mental illness
b. Dopamine
Movement and co-
ordination, emotions,
voluntary judgement,
release of prolactine
Decreased levels:
Parkinson’s disease
and depression
Increased levels:
Mania &
schizophrenia
c. Serotonin
Sleep, arousal, libido,
appetite, mood, aggression,
pain perception, co-
ordination, judgement
Decreased levels:
Depression
Increased levels:
Anxiety states
d. Histamine
Control of gastric secretions,
smooth muscle control,
cardiac stimulation,
stimulation of sensory nerve
endings; and alertness
Decreased levels:
Depression

49. Neurotrans
mitter
Function
Implications for
mental illness
III. Amino acids
a. GABA
Slowdown of
body activity
Decreased levels: Anxiety
disorders, schizophrenia
and various forms of
epilepsy
b. Glycine
Recurrent
inhibition of
motor neurons
Decreased levels: Are
correlated with spastic
motor movements
Increased levels: Glycine
encephalopathy
c. Glutamate
and aspartate
Relay of sensory
information and
in the regulation
of various motor
and spinal
reflexes
Increased levels:
Huntington’s disease,
temporal lobe epilepsy,
spinal cerebellar
degeneration

50. Neurotrans
mitter
Function
Implications for
mental illness
IV. Neuropeptide
a. Endorphins &
enkephalins
Modulation of pain
and reduced
peristalsis
Modulation of dopamine
activity by opioid peptides.
May indicate some link to the
symptoms of schizophrenia
b. Substance P Regulation of pain
Decreased levels: Huntington’s
disease and Alzheimer’s
disease
Increased levels: Depression
c. Somatostatin
Inhibits release of
norepinephrine,
stimulates release
of serotonin,
dopamine and
Decreased levels: Alzheimer’s
disease
Increased levels: Huntington’s
disease

51. Neurotransmitters and related
mental disorders
Neurotransmitter
related state
Mental disorder
Increase in dopamine level schizophrenia
Decrease in norepinephrine
level
Depression
Decrease in serotonin level Alzheimer’s disease
Decrease in GABA level Anxiety
Decrease in glutamate level Psychotic thinking

52. Most important
neurotransmitters
• Acetylcholine is important in
conceptualizing the pathology and
treatment of Alzheimer's disease and
parkinsonism
• Dopamine is important in conceptualizing
the pathology and treatment of
schizophrenia and parkinsonism
• GABA is important in conceptualizing the
pathology and treatment of anxiety

53. • Glutamate is an excitatory
neurotransmitter and might be
important in conceptualizing the
pathology and treatment of
Alzheimer's disease
• Norepinephrine is important in
conceptualizing the pathology and
treatment of mania and depression
• Serotonin is important in
conceptualizing the pathology and
treatment of mania and depression.

54. Hormone functions and
implications for mental illness
Hormone Functions Implications for
mental illness
Antidiuretic
hormone
Conservation of body
water and maintenance
of BP
Altered pain
response, modified
sleep pattern
Oxytocin Contraction of the
uterus for labor; release
of breast milk
May play role in
stress response by
stimulation of
ACTH
Growth
Hormone
Growth in children;
protein synthesis in
adults
Anorexia nervosa

55. Hormone Functions Implications for mental
illness
TSH Stimulation of
thyroid hormone
secretion, needed
for metabolism of
food and
regulation of
temperature
Increased levels: insomnia,
anxiety, emotional lability
Decreased levels: depression &
fatigue
ACTH Stimulation of
cortisol secretion;
which plays a role
in response to
stress
Increased levels: mood
disorders, psychosis
Decreased levels: depression,
apathy, fatugue, alzheimer’s
disease
Prolactin Stimulation of
milk production
Increased levels: depression,
anxiety, decreased libido,
irritability
Decreased levels: negative
symptoms in schizophrenia

56. Hormone Functions
Implications
for mental
illness
Gonadotropic
hormone
Stimulation of
estrogen secretion,
progesterone and
testosterone
Increased levels:
increased sexual
behaviour and
aggressiveness
Decreased levels:
depression and
Anorexia nervosa
Melanocyte
stimulating
hormone
Stimulation of
ssecretion of
melatonin
Increased levels:
depression