Paper 2: Bio-Psychology (REDUX)

Define the Central Nervous System

The brain receives information from sensory receptors and transmits signals to muscles and glands through the spinal cord (a collection of nerve cells in the spinal column)

* The brain is composed of the cerebrum, cerebellum, and brain stem, which enables conscious awareness and activates bodily functions
* The spinal cord transmits information and allows the brain to monitor bodily processes and coordinate voluntary actions
* The spinal cord also transmits simple reflexive action without brain involvement

Outline the Brain

The Cerebral Cortex is composed of grey matter and involved in higher cognitive, sensory, and motor tasks

* The brain is lateralised into two halves, the logical left and creative right, which communicate through the corpus callosum
* The cerebrum is divided into four lobes


1. Frontal Lobe (Logic and reasoning)
2. Occipital Lobe (Visual information)
3. Temporal Lobe (Auditory information)
4. Parietal Lobe (Integrates sensory information and aids spatial navigation)

Define the Peripheral Nervous System

The nervous system outside of the CNS, which includes the network of nerve cells which transmit impulses to-and-from the brain

* The Somatic Nervous System is a subdivision of the PNS and is composed of neurons involved in conscious and motor activity
* The Autonomous Nervous System is a subdivision of the PNS and is composed of neurons involved in unconscious activity with visceral organs

Define the Somatic Nervous System

The Somatic Nervous System is composed of nerve cells, or neurons, which transmit information

* Information is received by sensory neurons that transmit impulses to the CNS into complex sensations
* Information is transferred from sensory input to motor output through relay neurons (inter-neurons) within the brain and spinal cord
* Information is transmitted to effector organs, such as muscles, to contract or release, and gland, to produce or end production of a neurotransmitter

Outline the Structure of a Neuron

Neurons are composed of three segments: the axon, cell body, and dendrites

* The dendrites receive signals from other cells and transmit an action potential to the cell body
* The action potential carries into the axon and terminates at the axon terminal
* A myelin sheath can form an insulating layer around the axon to transmit signals faster

Outline Synaptic Transmission

1. The action potential strikes the membrane at the axon terminal of the pre-synaptic neuron
2. Channels release Calcium ions to prompt the vesicles to release neurotransmitters into the synapse
3. The neurotransmitters diffuse within the synapse and bind to receptors in the post-synaptic neuron
4. Depending on the neurotransmitter, the


1. Excitatory neurotransmitters, such as Adrenaline, increase the likelihood of a cell to fire an impulse
2. Inhibitory neurotransmitters, such as Serotonin, reduce the likelihood of a cell to fire an impulse
5. The neurotransmitters experience re-uptake and the effect is terminated

Define the Autonomic Nervous System

Regulates involuntary bodily process, such as digestion and the circulatory system, to maintain homeostasis without conscious awareness through two subdivisions

* The Sympathetic Nervous System is involved in the fight-or-flight response, where homeostasis is disrupted because of an emergency
* The SNS increases heart-rate/blood-pressure, dilates blood vessels, and inhibits digestion to release energy
* The Parasympathetic Nervous System is involved in the relaxation of the body to homeostasis following the fight-or-flight response
* The PSNS reduces heart-rate/blood-pressure, constricts blood vessels, and returns digestion to conserve energy

Define the Endocrine System

A network of endocrine glands that release hormones which stimulate and regulate cell activity, which causes physiological changes in an individual

* The Hypothalamus is a brain region that activates the Pituitary Gland, which stimulates and inhibits hormone production in other glands
* The anterior releases ACTH to the adrenal gland to produce cortisol during the fight-or-flight response
* The posterior releases LH and FSH to stimulate hormone production for sexual reproduction

Define the Fight-or-Flight Response

When an individual feels threatened, the amygdala in the brain sends a distress signal to the hypothalamus to activate the fight-or-flight response

* For acute stressors, the Sympathetic Nervous System triggers the adrenal medulla to release adrenaline to cause physiological differences
* Once a threat passes, the Parasympathetic Nervous System triggers the adrenal medulla to terminate the release of adrenaline
* For chronic stressors, the HPA Axis activates


1. The Hypothalamus releases the hormone CRH
2. CRH levels stimulate the Pituitary Gland to release the hormone ACTH into the bloodstream
3. ACTH activates the Adrenal Cortex to produce stress hormones such as Cortisol until the threat passes

Evaluate the Fight-or-Flight Response

* Taylor suggests that females are more likely to follow the ‘Tend-and-Befriend’ response
* Tend: Nurturing behaviours
* Befriend: Protective alliances with others
* Gray argues that the first reaction to a threat is actually ‘Freeze’, where the animal is hyper-vigilant and alert
* Negative consequences; Cortisol can suppress the immune system during viral infection
* Von Dawans argues that stress can lead to higher levels of cooperation

Outline the Biological Rhythms

Biological rhythms are controlled through endogenous pacemakers, such as the Suprachiasmatic Nucleus, and exogenous zeitgebers, such as light

* Circadian rhythms refer to biological processes that occur on an approximately 24-hour basis
* Ultradian rhythms refer to biological processes that occur frequently throughout the day
* Infradian rhythms refer to biological processes that occur infrequently more than a day

Define the Sleep/Wake Cycle

A Circadian Rhythm involving sleep, where homeostatic control requires the individual to accumulate a need for sleep as they remain awake

* Light strikes photo-receptors in the eye, which triggers a signal to the optic chasm that is relayed subsequently to the Suprachiasmatic Nucleus
* The SCN additionally synchronises the rhythms of cells primarily through Photoentrainment
* The SCN activates the Pituitary Gland to either stimulate or inhibit Melatonin production in the Pineal Gland
* Siffre conducted a case study on himself where he was deprived of exogenous zeitgebers in a cave, where he found that his sleep/wake cycle would settle on a 25-hour Circadian Rhythm

Evaluate the Sleep/Wake Cycle

* Aschoff and Wever found that participants deprived of exogenous zeitgebers settled to a sleep/wake cycle of 25 hours
* De Coursey found that chipmunks with a damaged SCN would die or disappear after 80 days in the wild
* Morgan found that implanted SCNs would transfer sleep/wake cycles
* Methodology; SCN research often has confounding variables
* Buhr argues that body temperature is more important than light as an exogenous zeitgeber in the sleep/wake cycle

Define the Sleep Stages

An Ultradian Rhythm during sleep which repeats every 90-100 minutes throughout the night between NREM and REM Sleep stages

* Stage 1: Hypnagogic

Characterised by alpha/theta waves, mild hallucinations, and myoclonus

* Stage 2: Light Sleep

Characterised by theta waves, as well as low heart rate and blood pressure

* Stage 3-4: Deep Sleep

Characterised by delta waves, as well as rhythmic breathing and limited muscle movement

* Stage 5: REM (Rapid Eye Movement) Sleep

Characterised by similar brain activity to wakefulness + delta waves, vivid dreams, and muscle atonia (paralysis)

Evaluate the Sleep Stages

* Dement and Kleitman found a mean average of a 92-minute sleep cycle
* Gardner remained awake for 264 hours and experienced problems such as slurred speech and irritability
* Dement found REM-deprived participants more aggressive
* Borbely found that REM-deprived participants made 31 attempts to enter REM throughout the night
* Methodology; research often conducted in controlled conditions, and so may not be representative

Define the Menstrual Cycle

An Infradian Rhythm that occurs every 28 days, which is regulated by hormone production

* The pituitary gland produces Follicle-Stimulating Hormone to stimulate egg-containing follicles in the ovaries and Luteinising Hormone to stimulate ovulation
* Oestrogen promotes ovulation
* Oestrogen levels are highest at the half-way point of the Menstrual Cycle during ovulation
* Progesterone thickens the womb lining with blood to prepare for possible embryo development
* Progesterone levels are highest after ovulation

Evaluate the Menstrual Cycle

* McClintock used a longitudinal study and found that 68% of females experienced menstrual cycle changes when in contact with pheromones from other women
* Methodology; small sample + other factors
* Reinberg used a case study and found that the menstrual cycle shortened to 25 days
* Evolutionary psychologists suggest a reason for menstrual synchrony was to increase survival so that childcare could be shared between psychologists
* The majority of research struggles to find evidence for menstrual synchrony

Define Localisation of Function

Specific brain locations govern different bodily functions

* The Motor Cortex in each hemisphere of the frontal lobe is responsible for voluntary movement
* The Somatosensory Cortex in the parietal lobe detects and processes sensory information to create sensations such as touch and pain
* Broca’s Area in the left hemisphere of the frontal lobe controls language production
* Wernicke’s Area in the left hemisphere of the temporal lobe that processes language

Evaluate Localisation of Function

* Petersen found that Broca’s Area would activate during reading tasks while Wernicke’s Area would activate during listening tasks
* Lashley removed 10-50% of rat brains and found that the rats could still learn the layout of a maze
* Application; research into localisation of function can help create treatments for Aphasia
* Expressive Aphasia
* Receptive Aphasia
* Global Aphasia

How is sensory information processed?

Visual information is received once light strikes the retina


1. Optic Nerve transmits information to the Thalamus
2. Thalamus transmits information to the Visual Cortex in the Occipital Lobe
3. Visual information is processed in different brain regions to determine colour and shape

Auditory information is received once sound strikes the Cochlea in the Inner Ear


1. Auditory Nerve transmits information to the Brain Stem for basic procession (e.g. volume, duration)
2. Brain stem transmits information to the Thalamus
3. Thalamus transmits information to the Auditory Cortex in the Temporal Lobe for deeper processing

Define Plasticity

The brain’s ability to adapt over a lifetime through synaptic pruning, where underused neural pathways are removed, while useful connections are strengthened

* Maguire found London taxi drivers had more grey matter in the posterior hippocampus, which is associated with spatial navigation
* Maguire also found a positive correlation between grey matter and job experience
* Kuhn found an increase in grey matter for participants that regularly played video games
* Draganski found that medical students had a larger hippocampus and parietal cortex after exams
* Mechelli found that bilingual people had a larger parietal cortex compared to monolingual people

Define Functional Recovery

After physical trauma, the brain is able to rewire to reallocate function to another brain area

* Functional recovery is achieved through reformation of blood vessels, axonal sprouting, and the use of homogeneous brain regions
* Danelli found that EB, whose left hemisphere was removed at 2, saw improved language fluency at 5 years-old and appeared virtually normal by 17

Evaluate Plasticity and Functional Recovery

* De la Plata found Functional Recovery decreased in older patients compared to younger patients
* Schneider found that the time somebody spent in education improved their functional recovery
* 60-80% of amputees suffer Phantom Limb Syndrome due to plasticity in the Somatosensory Cortex
* Application; research can help recovery after brain trauma such as strokes (Neurorehabilitation)

Define Hemispheric Laterlisation

The brain is lateralised into two hemispheres with functional specifications

* The right hemisphere controls creative tasks, such as intuition and spatial tasks
* The left hemisphere controls cognitive tasks such as language and analytical thinking
* Contralateral control refers to how either hemisphere controls the opposite side of the body
* The hemispheres share information through the corpus callosum

Outline Sperry and Gazzaniga’s Research

Sperry researched participants with a Commissurotomy where the corpus callosum was removed, which would prohibit inter-hemispheric communication

* Sperry used a T-Scope and instructed participants to focus on a fixation point to isolate information from each hemisphere
* Sperry found participants could identify visual information from the right side but not the left side
* The left hand could point to a matching object but could not verbalise information
* If images were projected simultaneously, patients could identify the right image but could only draw the left image
* Objects felt on the right side could be described, but both sides were able to identify a specific object from others

Evaluate Hemispheric Lateralisation

* Methodology; standardised procedure and controlled conditions
* Methodology; small and unrepresentative sample
* Application; debate about the hemispheres

Outline Functional Magnetic Resonance Imaging (fMRI)

fMRI machines detect changes in oxygenation as blood flow becomes redirected to active brain regions because of the haemodynamic response

* Virtually risk free and non-invasive
* High spatial resolution (by the millimeter)
* Can only detect blood flow and cannot detail specific neural activity
* Poor temporal resolution (4-5 seconds)

Outline Electroencephalogram (EEG)

An EEG measures electrical activity with electrodes fitted into a skull cap to scan and represent brainwave patterns

* Can diagnose medical conditions such as epilepsy with unusual brainwave activity
* High temporal resolution (real time)
* Poor spatial resolution (cannot detect deeper brain activity, such as in the hippocampus)

Outline Event-Related Potentials (ERP)

An ERP uses similar equipment to an EEG but also shows a stimulus to patients that allows researchers to analyse brain activity related to the stimulus

* Quantitative data; provides continuous information in response to a stimulus
* Can identify mental health issues, such as phobias in response to phobic stimuli
* Impossible to eliminate extraneous brainwave activity which could interfere with research

Outline Post-Mortem Discussion

A PME is an examination of a human brain to investigate structural abnormalities, which is typically performed for severe mental illness

* Formed a foundation for certain concepts, such as Broca’s Area and Wernicke’s Area
* Causation; brain damage may have been the result of physical abuse or decay
* Ethics; some patients may have been too ill or injured to provide informed consent