B6: Brain and Mind Notes

Stimulus=Change in environment

Response=Action you take based on the stimulus

-Muscles contract-->escape quickly

-Knee jerk reflex

Simple reflex-Involuntary

1. Find food, shelter, mate

2. Escape predators

3. Conditions in environment e.g. too hot

If conditions change-->Can't change habits easily/ learn from experience

Complex animals= more likely to survive b/c they change behavior when environmental conditions change b/c they make conscious decisions

Innate behaviour=Inherited through genes

-Pupil reflex-Pupil becomes smaller when it gets darker, b/c allows less light in

Newborn reflexes

1. Missing at birth                          = Baby NERVOUS SYSTEM is not working properly

2. Present when should disappear

e.g.     Stepping:   Disappears and reappears as he learns to walk.

           Grasping:  Pull away finger=tighter grip. Disappears.

           Startle:     Loud noise/moved quickly. Screaming and spreading arms and legs.

           Sucking:    Replaced by VOLUNTARY sucking

           Rooting:    Stroke cheek=looks for food

Simple reflexes increase survival chances e.g. warning colours protect from predators

a.k.a Cot death

Simple reflexes not matured properly

1. Fetus detects 02 in blood is low-->moves less b/c less 02 will be used up in respiration

2. Airways covered (e.g. duvet), baby moves more-->MORE 02 used up in respiration

3. Baby lies still=Suffocation

Prevention:

-Backs to sleep b/c nose airways won't be blocked

-Not use soft bedding b/c more likely to block airway

-Place at end of the bed so if it moves it will have space to go back

Receptors- Detects stimuli e.g. pain receptor in skin

Sense Organs

Vision- Light entering eyes produces a 3-dimensional image

1. Light entering eye=Bent by cornea and lens

2. Pupil changes size to control amount of light entering

3. Nerve impulse carried from cells in retina to brain by optic nerve

4. Nerve impulses travel along NEURONS to optic nerve

5. Cells in back of eye respond to light

Effectors are glands or muscles

Can form parts of complex organs

Nerve impulses bring about fast, short-lived responses

Glands contain hormone secreting cells (release ADH)

Hormones travel along blood-->Response is slower but longer-lasting

Muscle cells CONTRACT

Evolution-->complex multi-cellular organisms

Nervous and hormonal systems allow animals to respond to surroundings= SURVIVAL

Cells in nervous system carry nerve impulses

CNS-Every part of the body is linked to the brain and spinal cord through sensory and motor neurons=Peipheral Nervous System

Nerves= specialised cells called neurons

Neurons have: Nucleus, cell-membrane around cytoplasm (axon)

Axons carry electrical impulses

Fatty (myelin) sheath insulates the neuron and increases speed of the nerve impulses

Branched endings make connections with other neurons/effectors

1. Stimulus is the candle

2. Pain receptors in the skin

3. Nerve impulses travel along the sensory neuron to CNS

4. Relay neuron on spinal cord carries nerve impulses to the motor neuron (it doesn't go the brain, it skips it so no information is ever processed)

6. Nerve impulses are carried from the motor neuron to the effector

7. Effector causes the muscle to contract

Transmitter substances (chemicals) are used to pass nerve impulses along the synapses

1. An electrical impulse travels along an axon.
2. This triggers the nerve-ending of a neuron to release chemical transmitters.
3. These chemicals diffuse across the synapse (the gap) and bind to the receptor molecules on the membrane of the next neuron.
4. The receptor molecules on the second neuron binds to only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the electrical impulses

Serotonin

Feelings of pleasure-->survival e.g. food=pleasure-->eating-->survival

Lack of serotonin=Depression

Prozac is an anti-depressant

Causes a higher concentration of serotonin in synapses-->person is happier

Blocks the re-uptake channel therefore serotonin is trapped-->happiness

MDMA=Ecstasy

Long-term usage--> synapses destroyed in pleasure pathways of the brain

Effects:

• Anxiety
• Depression
• Poor attention span and memory
• Interferes with body temperature control-->hot sometime, cold other times                                                                                 =FATAL
• Slows down ADH production in brain 

Chest pains (Angina) triggered by excitement or stress

Nerve impulses stimulate the heart to speed up-->lack of 02 in heart muscles

Beta blockers:

• Reduce transmission of nerve impulses across synapses-->heart stops speeding
• Helps control nerve impulses in heart to ensure steady heartbeats

Neuroscientists study the brain

Brain=large mass of neurons which process information coming from receptors

Brain allows you to learn from experience

Consciousness=aware of your surroundings

Complex animals

Cerebral cortex is responsible for:                                                                

• Memory
• Intelligence                                            =makes up the MIND
• Language
• Consciousness

Each area of the cerebral cortex has a function

Complex beaviour allows you to adapt easier e.g.social interaction

Penfield applied electricity to stimulate the regions in the cerebral cortex in order to identify which muscles they controlled

No pain receptors in brain so patients were unharmed

fMRI scans show which areas of the brain are active (there is a greater flow of blood in active areas b/c it requires more energy to fulfil complex tasks)

Provides detailed information on brain structure without opening a skull

Learnt behaviour (conditioning) enables you to chnage your behaviour if the environment changes

Pavlov's experiment:

• Dog salivates (response) at sight of food (primary stimulus)
• Dog salivates when seeing food and bell (seconday stimulus) ringing at the same time
• Repeat over a period of time
• Dog salivates when just seeing the bell b/c it has gotten used to the bell being associated with food

Predators develop a conditioned reflex to animals with warning colours

a  +      -->

1. Hot plate is the stimulus

2. Pain receptors in skin are stimulated

3. Impulses travel along sensory neuron to spinal cord

4. Impulses are sent to a motor neuron, then to the muscle

5. Nerve impulse from the brain stops the reflex-You don't drop the plate                       

Animal testing used to study the brain e.g. cutting it open

Studying mental-health patients has improved medical knowledge

It is wrong to use animals, they are living creatures too/vertebrates

It isn't fair or morally right

New technologies (fMRI) have helped as analyse the brain

Social learning is the way humans/animals behave towards each other

Neurons in the brain are connected to form NEURON PATHWAYS

They develop when:

• A nerve impulse travels along a particular pathway, one neuron to another
• A connection is made between the neurons (it branches out and connects)
• If the experience is repeated, more nerve impulses follow that pathway
• Therefore, the connections between the neurons are strengthened
• This makes it easier for the nerve impulses to travel
• Hence, your response is easier to make

Repetition strengthens pathways

Visualisation strengthens pathways b/c thinking about using a muscle, triggers nerve impulses to that muscle

Feral children's development of new pathways would've passed, thus they find it difficult to learn new things

Memory is the ability to store and retrieve information

Long-term memory is a lasting storage of information. There is no limit to it.

Alzheimers disease-->not knowing what day it is BUT can remember their childhood

Therefore, short/long-term memory works separately in the brain.

Sensory memory store is used to store sound and visual information for a short time

Short-term memory can store up to 7 items, hence you should break it into chunks

The use of sensory, long-term and short-term memory

Explains how neurons in the brain work to give you memory

• Words on page (stimulus) are read from the eyes (receptor=retina)
• Nerve impulses travel from eyes to sensory memory (visual and sound)
• Some sensory memory is passed to short-term memory (only information that you pay attention to is passed on)
• More information arrives
• Short-term memory cannot hold, therefore information is lost
• Some information is passed to long-term memory-You will remember these words
• The last bits of information your short-term memory receives will be remembered

These words are usually the first and last words.

Repetition helps to memorise things.

Rehearsal moves information from long-term to short-term memory.

Rehearsed information is processed and stored rather than lost from short-term memory

More likely to remember if you process it deeply

Processing can be through the information meaning something to you, or a pattern

Active working memory=Short-term memory:

• -Holds and processes information that you are consciously thinking about
• -Communication between long and short-term memory is in both direction-->retrieve and  store information for later

A highlighter pen processes information for active memory