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8/3/2019 Lecture 2 - Biopsych
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PL1101E INTRODUCTION TO PSYCHOLOGY
SEM. 2 AY2010/2011
WEEK 2
Lecturer: Dr. Travellia Tjokro.
E-mail: [email protected]: AS4-03-41.
mailto:[email protected]:[email protected]8/3/2019 Lecture 2 - Biopsych
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TODAYSAGENDA
Biopsychology: The Brain & Behavior.
Ch. 4 of your textbook.
Focus today:
Structure of a neuron & neuronalinformation conduction brief.
Structure of the nervous system brief.
Brain: Basic neuroanatomy.
Hemispheric lateralization.
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STRUCTURE OF ANEURON
Neurons: the basic building blocks of the
nervous system.
Three main parts:
Soma: the cell body.
Dendrites: specialized receiving units.
Axon: conducts electrical impulses away from
the cell body to other neurons, muscles, or
glands. Myelin sheath.
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A motor neuron
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NEURONAL INFORMATION CONDUCTION
Resting potential:
Cell membrane.
At rest, the membrane maintains an electricalpolarization or a difference in the electrical
charge of two locations (i.e., inside the cellmembrane and outside the cell membrane).
The inside of the membrane is slightlynegative with respect to the outside.
(approximately -70 millivolts).
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NEURONAL INFORMATION CONDUCTION
Action Potential.
The electrical shift that occurs when a
neuron is stimulated.
Positive sodium ions enter the neuron, causingbrief depolarization.
Information is propagated down the axon.
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Refractory periods:
Absolute.
Relative.
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NEURONAL COMMUNICATION
Neurotransmitters: chemical substances
that carry messages across the synaptic
space to other neurons, muscles, or
glands. Step 1: synthesis: the transmitter molecules are formed.
Step 2: storage: transmitter molecules are stored in
synaptic vesicles (in axon terminal).
Step 3: release: action potential causes transmitter
molecules to move from synaptic vesicles across the gap.
Step 4: binding: transmitter molecules bind themselves
to receptor sites embedded in the receiving neurons cell
membrane.
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Neurotransmitters:
Excitatory.
Likelihood of AP.
Inhibitory.
Likelihood of AP.
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STRUCTURE OF THE NERVOUS SYSTEM
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Lets now focus on the brain anatomy
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THE BRAIN: BASIC NEUROANATOMY
The orientation in the brain.
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TO PUT THINGS IN PERSPECTIVE
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BASIC NEUROANATOMY
Three major subdivisions of the brain:
Hindbrain
Midbrain
Forebrain
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HINDBRAIN
Lowest and most primitive level of the brain.
Consists of:
Medulla oblongata (medulla)
Pons
Cerebellum
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Medulla: plays an important role in vital body
functions such as heart rate and respiration.
Pons: carries nerve impulses between higher and
lower levels of the nervous system.
Cerebellum: concerned with muscular movement
coordination, learning, and memory.
Regulates complex movements that require precise
timing.
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MIDBRAIN
Midbrain: contains clusters of sensory and motor
neurons.
Example:
Reticular Formation: alerts higher centers of the
brain that messages are coming and then either
blocks or allows those messages.
Centered roughly in the pons. The reticular formation is the
core of the brainstem running through the mid-brain, pons
and medulla.
Hindbrain structures, the midbrain and other
central structures of the brain combine and make
up the brain stem.
http://en.wikipedia.org/wiki/Ponshttp://en.wikipedia.org/wiki/Pons8/3/2019 Lecture 2 - Biopsych
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BRAINSTEM
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Image Source: http://thebrain.mcgill.ca/flash/a/a_11/a_11_cr/a_11_cr_cyc/a_11_cr_cyc_1b.jpg
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FOREBRAIN
The brains most advanced portion from an
evolutionary standpoint.
Cerebrum: the major structure of the
forebrain.
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FOREBRAIN
Subcortical structure examples.
Thalamus: switchboard that organizes inputs from
sensory organs and routes them to the appropriate
areas of the brain.
Hypothalamus: plays a major role in motivation andemotion.
Controls hormonal secretions that regulate sexual
behaviour, metabolism, reactions to stress, and
pleasure/pain.
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Limbic System: helps coordinate behaviors
needed to satisfy motivational and emotional
urges that arise in the hypothalamus.
Hippocampus: involved in forming and retrieving
memories. Amygdala: organises motivational and emotional
response patterns
Aggression and fear.
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Cerebral Cortex: a 1/4 in. sheet of gray,
unmyelinated cells that form the outermost layer
of the human brain
Fissures: folds in the cerebral cortex; allows
greater surface area in a smaller space
Fissures separate the brain into four lobes:
frontal, parietal, occipital, and
temporal
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THE FOUR LOBES
Occipital Lobe
Posterior end of cortex.
Striate cortex / primary visual cortex.
Visual input processing.
Parietal Lobe Postcentral gyrus / primary somatosensory cortex.
Temporal Lobe
Lateral portion of each hemisphere - near the temples.
Processing of auditory info, spoken language, complexvision.
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Frontal Lobes:
29% of human brain; less in all other
mammals
Least understood part of the brain
Damage can result in loss of intellectual
abilities, such as planning and carrying out
action sequences
Involved in emotional experience.
Prefrontal cortex executive functions.
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Lets look at some sample areas in the four
lobes
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Motor Cortex: controls the 600 or more muscles
involved in voluntary body movements.
Sensory Cortex: receives input from our sensory
receptors.
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Wernickes area: an area in the temporal lobe
that is primarily involved in speech
comprehension.
Brocas Area: an area in the frontal lobe that is
involved in the production of speech through its
connections with the motor cortex region.
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BrocaWernicke
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HEMISPHERIC LATERALIZATION
Lateralization of function:
Lateral to the side.
Lateralization specialization of function.
L hemisphere R hemisphere
A
P
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CORPUS CALLOSUM: THE BRIDGE
Corpus Callosum: a
neural bridge that
acts as a major
communication link
between the twohemispheres and
allows them to
function as a single
unit
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Left hemisphere:
Verbal abilities, speech, mathematical andlogical abilities
Aphasia: the partial or total loss of the
ability to communicate; results from damageto Brocas or Wernickes areas in the lefthemisphere.
Right hemisphere: spatial relations, faces, mentalimagery, musical and artistic abilities.
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So, how does each hemisphere get information
from the environment?
Each hemisphere of the brain gets input from the
opposite half of the visual world.
The visual field is what is visible at any moment.
Out in the environment.
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A lot of what we now know about the left and
right brain functional specialization come from
studies done on split brain people.
Split brain people: people with severed corpus
callosa.
To help in cases of severe epileptic seizures.
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So, how does an experiment with split brain
people go?
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ANOTHER EXAMPLE OF HEMISPHERIC LATERALIZATION
Brain damaged patients.
Not split brain.
Spatial processing.
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Other lateralized functions:
Language.
Emotions.
Spatial relations.