Biopsych

AQA - A Level Psychology - Biopsych

Divisions of Nervous System

Central Nervous System - Brain & Spinal Cord

Peripheral Nervous System - Autonomic Nervous System & Somatic Nervous System

Autonomic Nervous System - Sympathetic Nervous System & Parasympathetic Nervous System

Central Nervous System Role

Communication, controlling behaviours & regulatory physiology

Brain - Receives & processes sensory information

Spinal cord - conducts signals to and from the brain, controls reflex activities

Types of Neurons

Sensory Neurons (body cell in middle of axon)

Relay Neurons (short axon with no myelin sheath)

Motor Neurons (most normal neuron)

Neurons: Key Parts

Cell body

Dendrites

Axon

Myelin sheath

Nodes of Ranvier

Terminal buttons

Synaptic Transmission: Key Concepts

Action potential

Vesicles containing neurotransmitters

Open at membrane releasing NT into synaptic cleft

Reach specific receptors sites in post synaptic membranes

Neurotransmitters broken down by enzymes or reuptaked

Excitation & Inhibition: Key Concepts

Serotonin (inhibitory), dopamine (excitatory), adrenaline (excitatory)

Excitatory - increases positive charge which increases chances of another firing

Inhibitory - increases negative charge which decreases chances of another firing

Summation

Inhibitory/Excitatory post synaptic potential

Endocrine System: Key Concepts & Glands

Collections of glands that produce hormones for regulation

Negative feedback loop
Condition in body change from set point → change detected → corrective mechanisms activated → conditions return to set point → corrective mechanisms switched off

Examples: Glands, Hormone, Target, Functions

Pineal gland - melatonin - many - biological clock

Pituitary gland - FSH/LH, Oxytocin - Ovaries, uterus - menstrual cycle, birth contractions

Ovaries - oestrogen/progesterone - uterus - menstrual cycle

Fight or Flight Response

Amygdala senses danger

Hypothalamus commands ANS to activate sympathetic branch

Sympathetic branch stimulates adrenal medulla to release adrenaline and noradrenaline

Fight or Flight: Evaluation

- Gender Bias (Taylor)

- Additional freeze (Gray)

Fight or Flight: Gender bias research

Taylor (2000)

Females display tend and befriend

Higher levels of oxytocin and more advantageous than abandoning offspring

Research only conducted on males - beta bias

Fight or Flight: + Freeze Research

Gray (1988)

Most animals display freeze before fight or flight

Allows focusing of attention

Lobes

Frontal

Parietal

Occipital

Temporal

Cortexes

Motor

Somatosensory

Visual

Auditory

Broca’s Area: Key Words

Frontal lobe

Production

Lack fluency

Difficulty with prepositions

‘Tan’

Wernicke’s Area: Key Words

Temporal lobe

Comprehension

Fluent

Meaningless

Neologisms

Localisation of Function: Evaluation

- Equipotentiality (Lashley) Rat study

+ Support from research & case studies

Tan, Phineas Gage & PET scans (Tulving)

I/D: Nomothetic & Idiographic support

Localisation of Function: Equipotentiality Research

Lashley

Removed areas of cortex in rats learning maze

No area more important

Suggest higher cognitive processes aren’t localised

Localisation of Function: Research Support

Tan (Broca’s Area)

Phineas Gage (Amygdala/Frontal Lobe)

Tulving - PET Scans

Split Brain Research

Sperry & Gazzaniga

11 split brain patients due to epilepsy compared to those without split brain

Fixate on central point

Stimulus projected on a side for 1/10 sec

Asked to draw/name

Lateralisation: Evaluation

+ Support - Sperry

- Lateralisation changes with age (Szaflarski et al)

I/D: Biological Determinism - Certainty is useful

Split Brain Research: Methodology Evaluation

+ Well designed and standardised

- Small sample and confounding variable of medication

- Replication is rare

Lateralisation: Across Ages Research

Szaflarski et al (2006)

Language became more lateralised as age increased

After 25, lateralisation decreased with each decade

Plasticity: Key Concepts

Neural pathways

Experience

Frequency

Cognitive pruning

Plasticity Examples

Learning juggling

Playing video games

Meditation

Negative effects

Plasticity: Juggling Research

Boyke et al (2008)

Evidence of plasticity in 60 year old taught juggling

Found increases in grey matter in visual cortex

Reverse when practise stopped

Plasticity: Video games research

Kuhn et al (2014)

Practised Super Mario for at least 30 mins a day for 2 months

Found increased grey matter in several areas

More syanptic connection related to spatial navigation, planning, working memory and motor performance

Plasticity: Meditation

Davidson et al

8 Tibetan monks and 10 volunteers who’d never meditated

Asked to meditate for short periods

Increased gamma waves (coordinate neurons) in monks even before meditation

May also produce permanent changes

Plasticity: Negative Effects

Marijuana linked with excess dopamine release

Ketamine linked with permanent memory issues

Old age associated with dementia

Plasticity: Evaluation

+ Animal Study support (Kempermann)
H Animals not humans

+ Taxi Driver study (Maguire)

- Plasticity reduces with age but still possible

I/D: nomothetic

Plasticity: Animal Study

Kempermann (1997)

12 rats in basic and 12 in complex cages

Increased neural activity in hippocampus (spatial awareness and memory function)

Plasticity: Human Study

Maguire (2000) - Taxi Driver Study

16 right handed male taxi driver vs control non taxi driver

MRI showed significantly larger posterior hippocampus (spatial awareness and navigation)

Functional Recovery: Key Concepts

After truama

Rewiring

Mechanisms for recovery

Mechanisms for Recovery

Axon Sprouting

Recruitment of Homologous Areas

Denervation Supersensitivity

Stem Cells

Functional Recovery: Evaluation

+ Stem cells - Animal research support

- Age differences in functional recovery

I/D Biological determinism

Functional Recovery: Research

Tajri et al (2013)

Rats with brain injury given two groups

One received transplants of stem cells, other received placebo

3 months later, stem cell showed clear development of neuron like cells and solid stream of cells migrating

Ways of Studying the Brain

fMRI

EEG

ERPs

Post Mortem

fMRI: Key Concepts

Functional Magnetic Resonance Imaging

Structure & Function

Blood flow

Oxygen

Deoxygenated haemoglobin

Different magnetic quality

fMRI: Evaluation

+ Spatial resolution is high (1-2mm)

- Temporal resolution is low (1-4 secs)

- Expensive

EEG: Key Concepts

Electroencephalogram

Function

Electrical impulses

Electrodes

Intensity, size and frequency

EEG & ERPs: Evaluation

+ High temporal resolution (1-10 millisecs)

+ Effective diagnostic tool

- Low spatial resolutions (only detects cerebrum activity)

ERPs: Key Concepts

Event-Related Potentials

Function

Voltage change

Stimulus

Specific

Averaged over presentations

Filtered out EEG

Post Mortem Examination: Key Concepts

Structure

Study alive behaviour

Study after death

Correlation

Post Mortem Examination: Evaluation

+ Excellent spatial resolution

+ Generates hypothesis for further study

- No temporal validity

- Only correlational

- Ethics

Types of Biological Rhythm

Circadian (about a day)

Ultradian (less than a day)

Infradian (more than a day)

Biological Rhythms: Key Concepts

Cyclical change

Endogenous pacemakers
Internal body clocks

Exogenous Zeitgebers
External cues

Circadian Rhythms: Key Concepts

Sleep-Wake Cycle

Suprachiasmatic Nucleus (Area of Hypothalamus)

Light enters eye and travels to SCN

SCN regulates pineal gland activity

Light decreases: SCN increases melatonin
Light increases: SCN decreases melatonin

Case Study - Michel Siffre

Circadian Rhythm: Research

Michel Siffre

2 months living in French caves with no EZ

Monitored activities: when he felt tired, hungry and when he slept

Investigated extent to which EZ affects circadian rhythms

Maintained sleep/wake cycles of around 25 hours
Erratic at first then settled

Need for EZ to reset cycle

Circadian Rhythms: Evaluation

+ Siffre as support
H Case study with small sample & Poor control as Siffre had lamp and interacted with people through phone

+ Practical application to shift work
Desynchronisation, night worker suffer circadian trough at around 6am making more mistakes

- Individual differences
Can vary widely (Duffy) so generalisations hard to make

I/D: Biological Determinism
Controlled purely by SCN is determinist
H May have free will as some work in day over night

Circadian Rhythms: Individual Differences

Duffy (2001)

Some have natural preference for early to sleep and rise (Larks) and some are Night owls

Preferences change with age

Ultradian Rhythms: Examples

Sleep Stages

Basic Rest Activity Cycle
90 minute cycles throughout day, periods of alertness followed by a spell of fatigue

Sleep Stages: Key Concept

5 distinct stages - 90 minutes
Diff level of brain activity

REM - dreaming - very light sleep
Stages 1 & 2 - light sleep - alpha & theta waves
Stages 3 & 4 - deep sleep - delta waves

Sleep Stages: Research

Dement & Kleitman (1957)

Used EEG

Small sample

Normal diet (no caffeine or alcohol)

Ppts woken during REM- 80% remembered dreams
In non-REM 7% remembered dreams

Infradian Rhythms: Example

Human Menstrual Cycle

Human Menstrual Cycle: EPs, EZs

EP: Oestrogen & Progesterone, Pituitary Gland & FSH

EZ: Diet, Exercise, Stress

Human Menstrual Cycle

FSH causes follicle to mature an egg and release oestrogen & progesterone

O & P cause uterus lining to thicken and maintain

Ovulation occurs

If egg not fertilised, lining is shed

Ultradian and Infradian Rhythms: Evaluation

- Individual differences in sleep
Significant variations between people (Tucker)
Limits usefulness

+ Support for role of Exogenous Cues
Women synching and pheromone research (McClintock)

I/D Nature/Nurture

Sleep Individual Differences Research

Tucker (2007)

Large differences in ppts in terms of duration of each sleep stage

Factors like hormones, age, activity & biological differences

Menstrual Cycle Exogenous Cues Research

McClintock (1988)

10 year longitudinal study
29 women 20-35 years with history of spontaneous irregular ovulation

Pheromones gathered from women at points in menstrual cycle and then wiped under nose of other women daily

68% responded to pheromones
Cycle either shortened or lengthened depending on when collected

Endogeneous Pacemakers: Key Concepts

Suprachiasmatic Nucleus
Obtains info on light from optic nerve
Light penetrates eyelid and special photo receptors in eyes

Pineal Gland
SCN passes info on day length and light
During low light, pineal gland increases melatonin production and vice versa

Exogenous Zeitgebers: Key Concepts

Light
Key zeitgeber in humans
Resets SCN
Indirect influence on key processes that control functions like hormone & blood circulation

Social Cues
Influenced by norms of people around us as to what time we wake and sleep

Exogenous Zeitgebers & Endogenous Pacemakers: Evaluation

+ Research support for role of SCN
Squirrels sleeping (DeCoursey et al)

+ Research support for social cues
Jet lag study (Klein & Wegmann)

I/D: Nature vs Nurture
Interactionist as nature of Endogenous and nurture of exogenous

Role of SCN in Sleep Study

Decoursey et al (2000)

Destroyed SCN connections in 30 chipmunks

Radio collared and tracker for 30 days

More SCN damaged chipmunks killed by predators as damage affected sleep patterns

Social cues as Exogenous Zeitgebers Study

Klein & Wegmann (1974)

Circadian rhythms of air travelers adjust more quickly if they went outside more at destination

Thought to be because they were exposed to social cues of their new time zone