concept of psychobiology.concept of psychobiology.ppt

concept of psychobiology.concept of psychobiology.ppt

1. PRESENTATION
ON
CONCEPT OF PSYCHOBIOLOGY

BY
Ms. Sujitha.M
1
ST
YEAR M. SC. NURSING

2. Aim -At the end of presentation student
will gain in depth knowledge of concept of
psychobiology
Objective-
• Identify gross anatomical structures of the brain
and describe their functions.
•Discuss the physiology of neurotransmission in the
central nervous system.
•Describe the role of neurotransmitters in human
behavior.
•Discuss the association of endocrine functioning to
the development of psychiatric disorders.
•Describe the role of genetics in the development of
psychiatric disorders.
•Discuss the correlation of alteration in brain
functioning to various psychiatric disorders.

3. INTRODUCTION
•In recent years, a greater emphasis has
been placed on the study of the organic
basis for psychiatric illness. This
"neuroscientific revolution" began in earnest
when the 101st legislature of the United
States designated the 1990s as the "decade
of the brain." With this legislation came the
challenge for studying the biological basis of
behavior. Several mental illnesses are now
being considered as physical disorder that
are the result of malfunctions and/or
malformation of the brain.

4. CONT-
•This concept focuses on the role of
neurophysiologic, neurochemical,
genetic, and endocrine influences on
psy
­chiatric illness. Various diagnostic
procedures used to detect alteration in
biological function that may contribute
to psychiatric illness are identified and
the implications for psychiatric/mental
health nursing are discussed.

5. An organ that controls your emotions, your
thoughts, and every movement you make.

6. CORE CONCEPT
•Psychobiology is the study of the biological
foundations of cognitive, emotional, and
behavioral processes.

7. Anatomy & Physiology of the Human
Nervous System
•The nervous system is composed of two separate but
interconnected divisions:
•Central Nervous System (CNS)
–Composed of the brain, brain stem, and the spinal
cord
–Understanding of mental disorders involves in-
depth understanding of the structure and function
of the CNS
•Peripheral Nervous System (PNS)
–Contains peripheral nerves and includes cranial
nerves starting from just outside the brain stem

10. Divisions of the autonomic nervous system
•Parasympathetic division
•Sympathetic division
Serve most of the same organs but cause opposing
or antagonistic effects
10
Parasysmpathetic: routine maintenance
“rest &digest”
Sympathetic: mobilization & increased metabolism
“fight, flight or fright” or “fight, flight or freeze”

11. Where they come from
11
Parasympathetic:
craniosacral
Sympathetic:
thoracolumbar

12. 12

13. Central control of the
Autonomic NS
Amygdala: main limbic
region for emotions
-Stimulates sympathetic
activity, especially previously
learned fear-related behavior
-Can be voluntary when
decide to recall frightful
experience - cerebral cortex
acts through amygdala
-Some people can regulate
some autonomic activities by
gaining extraordinary control
over their emotions
Hypothalamus: main
integration center
Reticular formation:
most direct influence
over autonomic
function 13

14. Neuroanatomy of CNS
•I. Cerebrum
Largest part of the brain
Divided into left and right cerebral hemispheres
Each hemisphere is further subdivided into 4 lobes:
1.Frontal lobe
2.Parietal lobe
2.Occipital lobe
3.Temporal lobe

15. Neuroanatomy (cont)
II. Diencephalon
A.Hypothalamus
B.Thalamus
C.Pineal body
III.Cerebellum
IV. Brainstem
A. Pons
B. Medulla oblongata
C. Reticular activating system
D. Midbrain

16. Neuroanatomy (cont)
V.Basal Ganglia
VI.Limbic system
A. Hippocampus

17. Frontal Lobe
(Thought Processes)

18. Frontal Lobe
•Formulate or select goals
•Plan
•Decision making
•Insight
•Motivation
•Social judgment
•Expression of mood
•Voluntary motor ability starts in the frontal lobe
•Speech
•Memory
•reasoning
•problem solving skills

19. Frontal Lobe (cont)
•Neurospych testing and brain imaging studies
indicate that the frontal lobe seems to be involved in:
•Schizophrenia
•Obsessive compulsive disorders (OCD)
•Mood disorders
•Attention deficit hyperactivity disorders (ADHD)
•Dementias

20. Temporal Lobe
(Auditory)

21. Temporal Lobe
•Receives and processes auditory information
•Language comprehension
•Stores sounds into memory (language, speech)
•Moods & emotions

22. Occipital Lobe
(Vision)

23. Occipital Lobe
•Reception and integration of visual input

24. Parietal Lobe
(Sensory and Motor)

25. Parietal Lobe
•Receive and identify sensory information, ability to
read, to understand spoken language
•body awareness
•Abstraction
•Reading mathematics
•ability to recognize objects
•Calculate
•Write
•draw

26. Structures of the Diencephalon
•Hypothalamus
•Thalamus
•Pineal Gland

27. Hypothalamus
•Houses the pituitary gland and serves as a major control
center for maintaining physiological homeostasis
•Regulates some of the most basic human functions
•Sleep-rest patterns
•Body temperature
•Physical drives of hunger and sex

28. Thalamus
•A regulatory structure that acts as a gateway to the
cerebral cortex
•Relays all sensory info, except smell, from the PNS to
the CNS
•Helps filter incoming info to prevent the cortex from
being overloaded

29. Pineal Gland
•Secretes melatonin
•Possibly regulates sleep-wake cycle

30. Cerebellum
•Located in the posterior part of the brain behind the
brainstem
•Coordinates equilibrium, muscle tone, postural control,
and voluntary muscle activity

31. Brainstem
•Connects the spinal cord to the brain and contains the
control center for vital cardiac and respiratory functions
•Composed of:
•Pons
•Medulla oblongata
•RAS
•Midbrain

32. Brainstem (cont)
•Midbrain
–Unconscious regulation of motor activity
–Contains part of the basal ganglia which
manufactures the dopamine
•Pons
–Relay between the cerebrum and cerebellum
–Site of production for most of the brain’s
neurochemical
–Center to regulate breathing

33. Brainstem (cont)
•Medulla oblongata
•Responsible for conscious control of skeletal muscle
and is involved with balance and coordination
•Reticular activating system
•Stimulation of this area activates the cortex into a state
of alert wakefulness

34. Basal Ganglia
•Made up of cell bodies closely involved with motor
functions and association
•Involved in learning and programming of behavior
•For example: complex activities such as driving or
eating become so engrained that one does not
have to think consciously to perform them

35. Basal Ganglia (cont)
•Extrapyramidal motor system
•Muscle tone, common reflexes, and automatic
motor functioning of walking (posture) are
controlled by this track
•This track works by maintaining a balance
between excitatory and inhibitory neurons
•Diseases such as Parkinson’s and Huntington’s
cause dysfunction of this motor track and produce
abnormal muscle movements
•Antipsychotics also cause an alteration in
functioning of the basal ganglia and produce side
effects

36. Limbic System
•Instincts, drives, needs, and emotions are
considered functions of the limbic system
•Structures of the limbic system include:
•Amygdala
•Hippocampus

37. Amygdala
•Modulates common emotional states such as feelings
of aggression and anger, love, and comfort in social
settings
•Sexual arousal and aggression are also controlled by
the amygdala
•Researchers are looking into the misfirng of neurons
in the amygdala and the development of bipolar d/o

38. Hippocampus
•Plays a major role in the encoding, consolidation, and
retrieval of memories
•Damaged in Alzheimer’s disease

39. Neurophysiology -
Nerve Tissue
The tissue of the central nervous system (CNS)
consists of nerve cells called neurons that generate
and transmit electrochemical impulses. The structure
of a neuron is composed of a cell body, an axon, and
dendrites

40. Neurophysiology
•Structural features of neurons:
•1. Cell body
•2. Axon (stem)—transmits signals from the neuron’s
cell body to connect with other neurons and cells
•3. Dendrites—collect incoming signals from other
neurons and send the signal to the neuron’s cell body

41. Basic Properties of
Neurotransmission -
•Information is transmitted through the body
from one neuron to another. Some
messages may be processed through only
a few neurons, while others may require
thousands of neuronal connections. The
neurons that transmit the impulses do not
actually touch each other. The junction
between two neurons is called a synapse

42. Synapse -
The small space between the axon terminals
of one neu
­ron and the cell body or
dendrites of another is called the synaptic
cleft. Neurons conducting impulses toward
the synapse are called presynaptic
neurons and those conduct
­ing impulses
away are called postsynaptic neurons.

44. A chemical, called a neurotransmitter, is
stored in the axon terminals of the
presynaptic neuron. An electri
­cal impulse
through the neuron causes the release of
this neurotransmitter into the synaptic cleft.

45. Synthesis and Storage of NTs
•Most NTs are stored in the terminal region of the neuron
•NTs are often synthesized from chemicals in our diets
•Before released into the synapse, NTs are stored in
membranous sacs called vesicles which protects them
from being destroyed by enzymes

46. Release and Response of NTs
•NTs are released from the nerve terminal following electrical
stimulation—inward movement of Na+ followed by outward
movement of K+
•After being released, a NT binds to a receptor (a unique
protein found in the membrane of a neuron)
•The analogy of a “lock and key” describes this relationship
•The lock is the receptor and the key is the NT

47. Release and Response of NTs (cont)
•After the receptor is bound, the action of the 1
st

message, the NT, is converted into action by a
“second messenger.”
•Second messenger systems can be described as the
effects of a single NT being amplified through the
subsequent activation of multiple systems
•The effects of 2
nd
messenger systems last longer and
the process is called neuromodualtion

48. Neurotransmitters
•NTs can carry 2 different types of messages:
•Excitatory
•Inhibitory
•Nerve cells stimulated by an excitatory NT will be
“turned on” or stimulated to start some action
•Those stimulated by an inhibitory NT will be “turned
off” causing slowing or stopping actions

49. NTs common in Mental Disorders
•5 NTs are important to the understanding of mental
disorders:
•Acetylcholine (Ach)
•Dopamine (Da)
•Norepinephrine (NE)
•Serotonin (5-HT)
•Gamma-Aminobutyric acid (GABA)

50. Acetylcholine (Ach)
•Formation of Ach depends on the dietary intake of its
precursor choline (red meat, vegetables)
•Can have an excitatory or inhibitory effect
•The role of Ach in the brain is to mediate cognitive
function

51. Acetylcholine (Ach)
•Decreased Ach is thought to produce the memory
impairing effects of Alzheimer’s disease (AD)
•This is the reason Aricept is useful in treating AD
•Aricept inhibits cholinesterase—the enzyme that
breaks down Ach
•This increase the amount of Ach

52. Acetylcholine (Ach)
•2 types of Ach receptors:
•Muscarinic
•When muscarinic receptors are blocked, pts
experience anticholinergic side effects
•Nicotinic
•Activity at nicotinic receptors has been shown to
improve learning and memory performance

53. Dopamine (Da)
•Dopamine is synthesized from the amino acid
tyrosine
•Generally has an excitatory effect

54. Dopamine (Da)
•Da receptors are classified into 2 main families, D1
and D2
•The D2 receptor family is inhibitory and is the
target of the antipsychotic meds
•Da levels are thought to be increased in pts with
schizophrenia and mania
•Drugs used to treat schizophrenia act to decrease Da
levels or transmission
•Da levels are decreased in pt’s with depression

55. Norepinephrine (NE)
•Generally excitatory
•Most prevalent NT in the body
•Has 2 main receptor subtypes:
•Alpha
•Beta

56. Norepinephrine (NE)
•Drives the sympathetic nervous system—
“fight or flight” response
•Studies indicate that pt’s suffering from depression
have decreased NE
•Research also shows that excess NE increases startle
reactions and aggression and has been implicated in
mania and anxiety d/os

57. Serotonin (5-HT)
•Mostly inhibitory
•Synthesis of 5-HT requires dietary intake of
tryptophan
•Plays a role in sleep regulation, hunger, mood states,
and pain perception
•Plays a role in aggression and sexual behavior

58. Serotonin (5-HT)
•Low levels of 5-HT have been implicated in
depression, aggression, and violent suicide attempts
•5-HT is structurally similar to LSD
•This has led researchers to hypothesize that 5-HT
is also dysregulated in psychosis

59. Gamma Aminobutyric Acid
(GABA)
•Inhibitory
•When GABA receptors are activated, chloride enters the
cell causing inhibition
•Antianxiety meds cause CNS depression by prolonging the
time the chloride channels are open

60. Neuroplasticity, The Kindling Effect, and
Behavioral Sensitization

61. Neuroplasticity
•Refers to the ability of the brain and nervous system to
change structure and functioning
•Kindling/Behavioral Sensitization
•Less stimulus in needed to evoke a response

62. NEUROENDOCRINOLOGY
•Study of the interaction between the
nervous system and the endocrine system,
and the effects of various hormones on
cognitive, emotional, and behavioral
functioning.

63. NEUROENDOCRINOLOGY
•Human endocrine functioning has a strong
foundation in the CNS, under the direction
of the hypothalamus, which has direct
control over the pituitary gland. The
pituitary gland has two major lobes—the
anterior lobe (also called the
adenohypophysis) and the posterior lobe
(also called the neurohypophysis).

64. The Anterior Pituitary
(Adenohypophysis)
•The hypothalamus produces releasing
hormones that pass through capillaries
and veins of the hypophyseal portal
system to capillaries in the anterior
pituitary, where they stimulate secretion of
specialized hormones. The hormones of
the anterior pituitary gland regulate
multiple body function.

66. The Posterior Pituitary
(Neurohypophysis)
•The hypothalamus has direct control over
the posterior pituitary through efferent
neural pathways. Two hor
­mones are found
in the posterior pituitary: vasopressin
(antidiuretic hormone) and oxytocin. They
are actually produced by the
hypothalamus and stored in the posteri
­or
pituitary. Their release is mediated by
neural impulses from the hypothalamus

68. Glands and Hormones
•Anterior pituitary
•Posterior
pituitary
•Pineal
•Thyroid
•Parathyroid
•GH, PRL, ACTH,
TSH
Antidiuretic
hormone,
oxytocin
•Melatonin
•T4, T3, calcitonin
•PTH
Foundation for Integrated
Medicine

69. Circadian Rhythms
•Human biological rhythms are largely
determined by genetic coding, with input
from the external environment influencing
the cyclic effects. Circadian rhythms in
humans follow a near-24-hour cycle and
may influence a variety of regulatory
functions, including the sleep–wake cycle,
body temperature regulation, patterns of
activity such as eating and drinking, and
hormone secretion.

70. CONTINUED
•The 24-hour rhythms in humans are affected to a
large degree by the cycles of lightness and darkness.
This occurs because of a "pacemaker" in the brain
that sends messages to other systems in the body
and maintains the 24-hour rhythm. This endogenous
pacemaker appears to be the suprachiasmatic nuclei
of the hypothalamus. These nuclei receive projections
of light through the retina, and in turn stimulate
electrical impulses to various other systems in the
body, mediating the release of neurotransmitters or
hormones that regulate bodily functioning.

71. COTINUED
•Mechanisms of the circadian rhythms
include the following:
•The Suprachiasmatic nucleus.
•Genes that produce certain proteins.
•Melatonin levels.

72. Fig. 9-4, p. 269

73. COTINUED
•Melatonin secretion usually begins 2 to 3
hours before bedtime.
•Melatonin feeds back to reset the
biological clock through its effects on
receptors in the SCN.
•Melatonin taken in the afternoon can
phase-advance the internal clock and can
be used as a sleep aid.

74. The Role of Circadian Rhythms in
Psychopathology
•Circadian rhythms may play a role in
psychopathology. Because many
hormones have been implicated in
behav
­ioral functioning, it is reasonable to
believe that peak secretion times could
be influential in predicting certain
behaviors. The association of depression
to increased secretion of melatonin
during darkness hours is present.

75. COTINUED
•Neurochemical Influences. A number of
neurochemicals have been shown to
influence the sleep-wake cycle. Several
studies have revealed information about
the sleep-inducing characteristics of
serotonin

76. Genetics-
•Study of the biological transmission of
certain characteristic (physical and / or
behavioral) from parent to offspring.
•Human behavioral genetics seeks to
understand both the genetic and
environmental contributions to individual
variations in human behavior . This type of
study is complicated by the fact that
behaviors, like all complex traits, involve
multiple genes.

77. COTINUED
•The term genotype refers to the total set of genes
present in an individual at the time of conception,
and coded in the DNA. The physical manifestations
of a particular genotype are designated by
characteristics that specify a specific phenotype.
Examples of phenotypes include eye color, height,
blood type, language, and hair type. As evident by
the examples presented, phenotypes are not only
genetic, but may also be acquired (i.e., influenced
by the environment) or a combination of both. It is
likely that many psychiatric disorders are the result
of a combination of genetics and environmental
influences.

78. COTINUED
•Investigators who study the etiological implications
for psychiatric illness may explore several risk
factors. Studies to determine if an illness is familial
compare the percentages of family members with the
illness to those in the general population or within a
control group of unrelated individuals. These studies
estimate the prevalence of psychopathology among
relatives, and make pre
­dictions about the
predisposition to an illness based on familial risk
factors. Schizophrenia, bipolar disorder, major
depression, anorexia nervosa, panic disorder,
somatization disorder, antisocial personality disorder,
and alcoholism are examples of psychiatric illness in
which familial tendencies have been indicated.

79. Psychoimmunology
•The branch of medicine that studies the
effects of psychological and social factors
on the functioning of the immune system.

80. Implications of the Immune System in
Psychiatric Illness
•In studies of the biological response to stress, it
has been hypothesized that individuals become
more susceptible to physical illness following
exposure to a stressful stimulus or life event .
This response is thought to be due to the effect
of increased glucocorticoid release from the
adrenal cortex following stimulation from the
hypothalamic-pituitary-adrenal axis during
stressful situations. The result is a suppression
in lymphocyte proliferation and function.

81. COTINUED
•Increased production of epinephrine and
norepinephrine occurs in response to
stress, and may decrease immunity.
Serotonin has demonstrated both
enhancing and inhibitory effects on
immunity .

82. IMPLICATION OF
PSYCHOBIOLOGY IN NURSING
•Psychiatric nurses must integrate
knowledge of the biological sciences into
their practices if they are to ensure safe
and effective care to people with mental
illness.

83. ROLE OF NURSE IN MENTAL
ILLNESS
•Dealing with patients’ problems of attitude,
mood, and interpretation of reality
• Exploring disturbing and conflicting
thoughts and feelings
• Using the patient’s positive feelings
toward the therapist it bring about
psychophysiological homeostasis
• Counseling patients in emergencies,
including panic and fear
•Strengthening the well part of patients

84. BIBLIOGRAPHY
•Mary C. Townsend ,Psychiatric Mental
Health Nursing, Jaypee Brothers, Medical
Publishers (p) LTD,6
th
edition.
•R Sreevani, Mental Health and Psychiatric
Nursing, Jaypee Brothers, Medical
Publishers (p) LTD,2
nd
edition.
•http//www . google .com