AQA GCSE Psychology Unit 7 - The Brain and Neuropsychology

Central Nervous System

Brain : descision making and basic functions

Spinal cord : carries messages between brain and body

Peripheral Nervous System

• Somatic NS : takes info from sense organs and controls voluntary muscle movement

• Autonomic NS: controls homeostasis and involuntary movement such as breathing and digestion

Autonomic NS

• Sympathetic division

  • Fight or flight

  • a state of physical arousal

• Parasympathetic

  • Rest and Digest

  • works opposed to sympathetic to keep body balanced

Fight or Flight response

• Threat is present

  • Dilation of pupils to take in more info

  • Fast breathing to take in more oxygen

  • slow digestion as blood is redirected to muscles

• Threat is no longer present

  • Parasympathetic reverses Sympathetic changes

James-Lange theory of emotion

• Event > Arousal > Interpretation > Emotion

• Event occours and leads to activation of sympathetic division

• adrenaline is released creatinh physiological arousal

• brain interprets physiological changes and decides an emotion

Evaluation of James-Lange theory of emotion

• disconnecting nerves that tell the brain what is happening dont stop emotion from occouring

• Alternate Canon-Bard theory argues we experience emotion and physiological changes at the same tme

• James-Lange theory may be too simple

How do Neurons communicate

Neurons communicate using electrical and chemical signals

How many neurons are in the human body

About 110 billion neurons with 86 billion in the brain

Parts of a Neuron

• Dendrite: Receives signals from other neurons.

• Soma: Cell body that processes signals and maintains neuron life.

• Axon: Transmits impulses away from soma.

• Myelin Sheath: Insulates axon to speed signal transmission.

• Node of Ranvier: Gaps which increase transmission speed

• Axon Terminal: The point where neurotransmitters are released to communicate with other neurons or muscles.

Sensory neuron

• Long dendrites

• short axons

• Carry messages from PNS to CNS

Motor Neuron

• short dendrites

• longaxons

• Carry messages from CNS to effectors (Muscles or Glands)

Relay Neuron

• shortdendrites

• short axons

• connect two different neuron types

Parts of a Synapse

• Presynaptic Neuron: Sends the signal and contains synaptic vesicles.

• Axon Terminal: Releases neurotransmitters into the synaptic cleft.

• Synaptic Vesicle: Stores neurotransmitters for release.

• Neurotransmitters: Chemical messengers transmitting signals.

• Synaptic Cleft: Space where neurotransmitters travel to the postsynaptic receptor.

• Postsynaptic Receptor Site: Binds neurotransmitters to initiate response.

Neuroplasiticity

The brains ability to change and reorganise itself throught life

Hebb’s Thoery of learning and neuronal growth

• “cells that fire together wire together“

• The brain adapts in response to new learning (neuroplasticity)

• groups of neurons that fire together have stronger synaptic connections and are more efficient

• learning can be made permanent due to neuroplasticity

Evaluation of Hebb;s theory

• Methods used to investigate were scientific and objective

• Black cab drivers had larger areas that were used to store ‘internal maps’ than non cab drivers

• Hebb’s Theory reduces learning to the activity of the brain cells

Areas of the Brain

• Frontal

• Parietal

• Temporal

• Occipital

• Cerebellum

Function of areas within the brain

• Frontal: Movement + Higher processing like planning

• Parietal: Sensation

• Temporal: areas related to language speech and hearing

• Occipital: area for processing visual information

• Cerebellum: Balance/Coordination and fine movements

Broca’s area

controls speech production; damage impairs speech construction while interpretation remains intact.

Wernicke’s area

controls speech understanding; damage impairs speech interpretation while construction remains intact.

Montreal procedure

Surgeon exposes the brain under local anesthetic and stimulates areas with electricity while the patient describes sensations. in order to find the part responsible for starting siezures

Penfield’s Study of the interpretive cortex

• Research Design: over 1000 case studies

• Method: Surgeon exposes the brain under local anesthetic and stimulates areas with electricity while the patient describes sensations.

• Results: Stimulating the visual cortex would result in subjects seeing images etc….

• Conclusion: There was evidence for Localisation of Function (the idea that some psychological functions are controlled by particular parts of the brain) + the interpretive cortex is an area of the temporal lobe where interpretations of memories are stored

Evaluation of Penfield’s Study

• The study demonsatrated how certain areas of the cereberal cortex were involved in particular functions of the brain using living brains

• His study of the interpretive cortex was successful in isolating the precise area where patients’ memories were triggered

• The patients were epileptic and were not representative of the whole population

• The findings from his study were different for each induvidual

CT scan

• X- Rays fired at brain from inside doughnut shaped scanner which is rotated around to take images from many different angles

• Useful for showing structure

• more radiation than normal x-rays

• cant show brain activity

PET Scan

• Measures metabolic activity (respiration) within brain using a radioactive tracer placed into bloodstream. areas that emit most radiation are in use

• Show the brain in action

• results hard to interpret

• uses radiation

• very expensive

fMRI Scan

• track changes in blood oxygen levels to show which parts of the brain are in use

• shows the brain in action

• safer as no radiation is used

• very expensive

• 5 second delay between screen and brain

• patient must stay VERY still

Tulvng’s Gold Study

• 6 ppts injected with radioactive gold which spreasd through the bloodstream

• areas of the brain being used would show up on pet scan

• ppts asked to think about a “semantic“ memory (fact) four times

• then an episodic memory four times

Evaluation of Tulvings Gold study

• study produced scientific evidence: conclusion was made from brain scans which are hard to fake

• Sample was restricted:only six were tested and only 3 showed similar results

• semantic and episodic memores are often similar: memories of personal events also contain facts and knowledge