1. CENTRAL NERVOUS SYSTEM: PART 2 HIGHER BRAIN
Ahmed H. Ahmed
Cell Physiologist
Biology department-College of Science- Salahaddin University
2023-2024
for 2nd year dental students
Nervous system
3. MORE THAN ONE DEFINITION :
• the terms that are used to describe humans’ differences in thinking
skills
• others, sometimes used as near-synonyms, include cognitive ability,
cognitive performance, cognitive functioning, and mental ability
• “Intelligence is a very general mental capability that, among other
things, involves the ability to reason, plan, solve problems, think
abstractly, comprehend complex ideas, learn quickly, and learn from
experience
4. • It is not merely book learning, a narrow academic skill, or
test taking smarts. Rather, it reflects a broader and
deeper capability for comprehending our surroundings—
‘catching on’, ‘making sense’ of things, or ‘figuring out’
what to do’ .
• More succinctly, intelligence has been described as, “rapid
and accurate problem solving”
5. HIGHER BRAIN
Extremely large memory storehouse.
The cortex never functions alone but always in association lower
centers of the nervous system.
Lower brain functions, without cerebral cortex, are often imprecise.
Essential for most of our thought processes.
Lower brain centers initiate wakefulness in the cerebral cortex,
thus opening its bank of memories to the thinking machinery of
the brain.
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7.
8. CEREBRAL CORTEX
1. Sensory perception
2. Voluntary control of movement
3. Language
4. Personality traits
5. Sophisticated mental events, such as thinking, memory, decision
making, creativity, and self-consciousness
9. BASAL NUCLEI
1. Inhibition of muscle tone
2. Coordination of slow, sustained movements
3. Suppression of useless patterns of movement
10. THE BASAL NUCLEI PLAY AN IMPORTANT INHIBITORY
ROLE IN MOTOR CONTROL
The basal nuclei play a complex role in controlling
movement. In particular, they are important in
(1) inhibiting muscle tone throughout the body (proper
muscle tone is normally maintained by a balance of
excitatory and inhibitory inputs to the
neurons that innervate skeletal muscles),
(2) selecting and maintaining purposeful motor activity
while suppressing useless or unwanted patterns of
movement, and
(3) helping monitor and coordinate slow, sustained
contractions, especially those related to posture and
support
11. The importance of the basal nuclei in motor
control is evident in Parkinson’s disease (PD).
This condition is associated with a gradual
destruction of neurons that release the
neurotransmitter dopamine in the basal nuclei.
Because the basal nuclei lack enough dopamine to
exert their normal roles, three types of motor
disturbances characterize
PD:
(1) increased muscle tone, or rigidity;
(2) involuntary, useless, or unwanted movements,
such as resting tremors (for example, hands
rhythmically shaking, making it difficult or
impossible to hold a cup of coffee); and
(3) slowness in initiating and carrying out
different motor behaviors
12. THALAMUS
1. Relay station for all synaptic input
2. Crude awareness of sensation
3. Some degree of consciousness
4. Role in motor control
13. HYPOTHALAMUS
1. Regulation of many homeostatic
functions, such as temperature
control, thirst, urine output, and
food intake
2. Important link between nervous
and endocrine systems
3. Extensive involvement with
emotion and basic behavioral
patterns
4. Role in sleep–wake cycle
14. CEREBELLUM
1. Maintenance of balance
2. Enhancement of muscle tone
3. Coordination and planning of
skilled voluntary muscle
activity
15. BRAIN STEM
1. Origin of majority of
peripheral cranial
nerves
2. Cardiovascular,
respiratory, and
digestive control centers
3. Regulation of muscle
reflexes involved with
equilibrium and posture
4. Reception and
integration of all
synaptic input from
spinal cord; arousal and
activation of cerebral
cortex
5. Role in sleep–wake cycle
20. AMYGDALAE
The amygdalae ,Latin, from Greek ἀμυγδαλή, amygdalē, 'almond',
'tonsil', are almond-shaped groups of nuclei located deep and medially
within the temporal lobes of the brain in complex vertebrates,
including humans. Shown in research to perform a primary role in the
processing of memory and emotional reactions, the amygdalae are
considered part of the limbic system.
21. HIPPOCAMPUS
The hippocampus (named after its resemblance to the seahorse, from
the Greek hippos meaning "horse" and kampos meaning "sea
monster") is a major component of the brains of humans and other
vertebrates. It belongs to the limbic system and plays important
roles in the consolidation of information from short-term memory to
long-term memory and spatial navigation. Humans and other
mammals have two hippocampi, one in each side of the brain.
22. EMOTION, BEHAVIOR, AND MOTIVATION
The limbic system is not a separate structure but a ring of
forebrain structures that surround the brain stem and are
interconnected by intricate neuron pathways. It includes portions
of each of the following: the lobes of the cerebral cortex
(especially the limbic association cortex), the basal nuclei, the
thalamus, and the hypothalamus. This complex interacting
network is associated with emotions, basic survival and
sociosexual behavioral patterns, motivation, and learning.
23. WERNICKE’S AREA
Wernicke’s area is highly developed in the dominant side of the
brain – the left side in almost all right-handed people.
Wernicke’s area plays the greater role for higher
comprehension levels of the brain that we call “intelligence”.
This area was first
described in 1874 by
German
neurologist Carl
Wernicke
24. Severe damage in Wernicke’s area causes
inability to arrange words into coherent
thoughts, that means reading words without
knowing the thought they conveyed.
Activation of Wernicke’s area can call forth
complicated memory patterns else where.
25. BROCA’S AREA
Broca’s area initiates and
executes plans and motor
patterns for expressing
individual words or even
short phrases.
Broca’s area works in close
association with the
Wernicke’s language
comprehension center.
Paul Broca was born on 28 June
1824 in Sainte-Foy-la-
Grande, Bordeaux, France
27. CORPUS CALLOSUM
Manly, makes information stored in the cortex of one hemisphere available
to corresponding cortical areas of the opposite hemisphere .
Corpus callosum, a thick band consisting of an estimated 300 million
neuronal axons that connect the two hemispheres . The corpus callosum
is the body’s “information superhighway.” The two hemispheres
communicate and cooperate with each other by means of constant
information exchange through this neural connection
28. FACIAL RECOGNITION AREA
• Prosopagnosia is inability to
recognize faces.
• This occurs in people who have
extensive damage on the medial
undersides of both occipital lobes
and along the medioventral
surfaces of the temporal lobes.
• But why so much of the cerebral
cortex should be reserved for the
simple task as face recognition?
29. ANGULAR GYRUS
INTERPRETATION OF WRITTEN INFORMATION
Located between Wernicke’s area and visual area of the occipital
lobe
Damage to this area causes difficulty in interpreting words meanings
a state called dyslexia or “ word blindness”
30. THE DOMINANT HEMISPHERE
• The cerebral hemisphere that is more involved than the other
in governing certain body functions, such as controlling the
arm and leg used preferentially in skilled movements.
33. COMA
Coma Is defined as unconsciousness from which the
person cannot be aroused.
34. DEPRESSION
Depression is among the psychiatric disorders
associated with defects in limbic system
neurotransmitters. (As a distinction, psychiatric
disorders involve abnormal activity in specific
neurotransmitter pathways in the absence of
detectable brain lesions, whereas neurological
disorders are associated with specific lesions of the
brain and may or may not involve abnormalities in
neurotransmission
