Lecture 2 - Biopsych

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]


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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/Pons


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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.

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Lecture 2 - Biopsych