biopsych

Nervous System

Consists of the brain, spinal cord, and nerves, and serves as the body's control system.

Central Nervous System (CNS)

Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the CNS to the rest of the body. Subdivided into the ANS and SNS.

Autonomic Nervous System (ANS)

Is subdivided into the sympathetic and parasympathetic nervous system.

Somatic Nervous System (SNS)

Controls voluntary and involuntary (reflexes) muscle movement and receives information from sensory receptors.

The Endocrine System

Instructs glands to release hormones directly into the bloodstream to be carried towards target organs.

Thyroid Gland

Produces thyroxine hormone that regulate metabolism, body heat, and bone growth

Pituitary Gland

The master gland of the endocrine system that controls the release of hormones from all other endocrine glands.

Testes

Produce testosterone which is the male sex hormone.

Fight or Flight - Stage One

Stressor is perceived by hypothalamus, which triggers activity in the sympathetic branch of the ANS.

Fight or Flight - Stage Two

Stress hormone adrenaline is released from the adrenal medulla, which triggers physiological changes in the body which creates physiological arousal.

Fight or Flight - Stage Three

The parasympathetic nervous system returns the body to its resting state. (rest and digest)

Motor Neuron

Connects the CNS to muscles and glands.
Short dendrites and long axons.

Relay Neuron

Connects sensory neurons to motor and other neurons.
Short dendrites and short axons.

Sensory Neuron

Carries messages from the PNS to the CNS.
Long dendrites and short axons.

Dendrites

Branchlike protrusions of a neuron that carry nerve impulses towards the cell body

Axons

Carry impulses away from the cell body

Myelin Sheath

Protects the axon and speeds up the transmission of an impulse

Nodes of Ranvier

Gaps in the myelin sheath that speed up electrical transmission of an impulse

Electrical Transmission

Signals within neurons

Chemical (Synaptic) Transmission

Signals between neurons

lock and key model

Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site.

Inhibitory Effect

Neuron becomes negatively charged and less likely to fire

Excitatory Effect

Postsynaptic neuron becomes positively charged and more likely to fire.

Localisation of function

The extent to which different parts of the brain control different behaviours, processes or activities

Cerebral cortex

The part of the brain where information processing takes place. Divided into four lobes.

Motor Area

Located at the back of the frontal lobe.
Controls voluntary movement.

Damage to the motor area

May result in a loss of control over fine movements

Somatosensory Area

Located at the front of both parietal lobes.
Where sensory information from the skin is located.

Visual Area

Located in the occipital lobe at the back of the brain.

Auditory Area

Located in the temporal lobe.
Corned with the analysis of speech-based information

Broca's Area

Located in the left frontal lobe.
Responsible for speech production.

Damage to Broca's area

Speech that is slow, laborious or lacking in fluency (Broca's Aphasia)

Wernicke's Area

Located in the left temporal lobe.
Responsible for language comprehension.

Damage to Wernicke's area

Production of neologisms (Wernicke's aphasia)

Petersen et al (1988)

Used brain scans to demonstrate how Wernicke's area was active during listening and Broca's area was active during reading

Tulving et al (1994)

Semantic and episodic memories reside in different parts of the prefrontal cortex

Dougherty et al (2002)

44 OCD patients received cingulotomy. Follow-up after 32-weeks showed 1/3 had met the criteria for a successful response. Suggests behaviours associated with mental illness are localised.

Lashley (1950)

After removing part of rat's cortex's they were still able to remember parts of a maze; no area was proven to be more important than others in terms of ability. Suggests learning is too complex to be localised.

Plasticity

Ability of brain tissue to modify itself and take on new functions as a result of experience and new learning.

Maguire et al (2000)

London taxi drivers have greater volume of grey matter in the posterior hippocampus than in control group.
Positive correlation between time spent in job and how pronounced structural difference was.

Draganski et al (2006)

Imaged the brains of medical students 3months before and after exams.
Observed learning-induced changes in the posterior hippocampus and the parietal cortex.

Mechelli et al (2004)

Found a larger parietal cortex in the brains of people who were bilingual than a matched monolingual control group.

Functional Recovery

Following damage through trauma, the brain's ability to redistribute or transfer functions usually performed by damaged areas to other intact areas.

Axonal Sprouting

Growth of new nerve endings to connect with undamaged nerve cells and form new neuronal pathways

Doidge (2007)

Structural changes in the brain to allow for functional recovery (axonal sprouting, reformation of blood vessels, recruitment of homologous areas on the opposite side of the brain)

Practical application of plasticity

Neurorehabilitation —\> the brain reauires further intervention through means of physical therapy for FR to be entirely successful

Ramachandran and Hirstein (1998)

60-80% of amputees develop phantom limb syndrome, which is believed to be a result of cortical remapping in the somatosensory cortex that occurs as a result of limb loss.

Bezzola et al (2012)

fMRI scans observed reduced motor cortex activity in a group of 40-60 year old novice golfers after 40 hours of training

Hemispheric Lateralisation

The idea that the two halves of the brain are functionally different and certain mental processes and behaviours are controlled by one hemisphere rather than the other.

Sperry (1968)

Epileptic patients who had all undergone a commissurotomy - Split Brain research
Image or word presented to right visual field (processed by left hemisphere) and vice versa. —\> commissurotomy means information could not be shared between both hemispheres to give a full picture

Sperry - Describing what you see

Picture of an object show to right visual field - could easily explain what was seen.
Object shown to left visual field - could not.

Sperry - Recognition by touch

Could not attach verbal labels to objects in left visual field but could select matching object from grab bag using left hand.

Sperry - Composite words

'Key' on left visual field presented at same time as 'ring' on right visual field ➡️ would write word 'key' with left hand and say word 'ring'

Sperry - Matching Faces

Right hemisphere dominant in terms if recognising faces

Pucetti (1977)

Suggests that the two hemispheres are so functionally different that they represent a form of duality ➡️ we are two minds

Functional magnetic resonance imaging (fMRI)

Detects changes in blood oxygenation in different brain regions.
Produces 3D activation maps that show which parts of the brain are involved in a particular mental process

Haemodynamic response

When a brain area is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to the active area

Advantages of fMRI's

Virtually risk-free ➡️ No radiation
High spatial resolution

Weaknesses of fMRI's

Expensive
Poor temporal resolution
Can only measure blood flow, not individual neurons' activity

Electroencephalogram (EEG)

Graphical record of brain-wave activity and electrical impulses obtained through electrodes placed on the scalp and forehead

Advantages of EEG's

Invaluable in diagnosis (epilepsy; characterised by random bursts of brain activity)
High temporal resolution

Weaknesses of EEG's

Generalised nature of information ➡️ not useful for pinpointing exact sources of neural activity

Event-related potentials (ERP)

Changes in electrical activity in areas of the brain in response to specific stimuli or events
Statistical analysis of EEG data

Advantages of ERP's

More specific measurement of neural processes
High temporal resolution

Weaknesses of ERP's

Lack of standardisation in methodology
Hard to eliminate extraneous variables

Post-mortems

Brain is analysed after death to determine whether certain observed behaviours during the patients lifetime can be linked to abnormalities in the brain

Advantages of post-mortems

Vital in providing a foundation for early understanding ➡️ was the basis for Broca + Wernicke's conclusions
Help generate hypotheses for further research

Weaknesses of post-mortems

Observed damage may not be linked to the deficits under review, but some other trauma or decay
Patients may not be able to provide informed consent (HM couldn't but it happened anyway)

Temporal resolution

The precision of a measurement with respect to time

Spatial Resolution

The number of pixels utilized in construction of a digital image

Circadian Rhythm

Subject to a 24 hour cycle
ie sleep/wake cycle

Siffre

Deprived himself of natural light and sound and went underground for 2 months. Found his sleep/wake cycle adjusted to 25 hours.

Aschoff and Wever (1976)

Participants spent 4 weeks in a WWII bunker deprived of natural light. All but one extended sleep/wake cycle to 25 hours (one to 29 hours)

Folkard et al (1985)

12 people live in cave for 3 weeks, going to bed at 11:45pm and waking at 7:45am. Unbeknownst to participants, they gradually sped the clock until 22hours pass a day. Only one participant was able to comfortably adjust. Suggests circadian rhythm cannot be easily overridden by external environment.

Boivin et al (1996)

Night workers engaged in shift work experience a circadian trough around 6am, meaning mistakes and accidents are more likely

Knutsson (2003)

Shift workers are three times more likely to develop heart disease

Baraldo (2008)

Research into circadian rhythms has revealed that there are certain peak times during the day or night when drugs are at their most effective

Infradian Rhythms

Biological rhythms that occur once a month or once a season (subject to a frequency of less than one cycle per 24 hours)

Stern and McClintock (1998)

29 women with a history of irregular periods. Pheromones collected from 9 women at diff stages of their periods using cotton pad under armpit. Other 20 women given pad from 1st day of sample 9 period, then 2nd and so on.
68% of women experienced changes to menstrual cycle bringing them closer to odour donor.

Methodological issues in synchronisation studies

Many confounding variables not controlled (ie stress, diet)
Small sample - hard to generalise

Seasonal Affective Disorder (SAD)

Depression that involves recurrent depressive episodes in a seasonal pattern.
Melatonin is implicated in SAD because at night the pineal gland secretes melatonin until dawn (when there is light) but during winter the light comes later so melatonin is secreted for longer.

Ultradian Rhythm

Biological Rhythm with a period of less than 24 hours (more than one cycle in one day)

The Sleep Cycle - Stages 1 and 2

Light sleep - easily woken
Alpha and theta waves

The Sleep Cycle - Stage 3 and 4

Slow wave sleep - harder to rouse
Delta waves

The Sleep Cycle - Stage 5

Rapid Eye Movement
Highly correlated with experience of dreaming

Evolutionary basis of the menstrual cycle

Females menstruating together can therefore fall pregnant at the same time meaning newborns can be cared for collectively and have an increased chance of survival

Schank (2004)

Too many females cycling together within a social group creates more competition for the highest quality males ➡️ avoidance of menstrual synchrony may be more adaptive

Dement and Kleitman (1957)

Monitored the sleep patterns of 9 adults using EEG, controlling for caffeine or alcohol.
REM correlated with dreaming.
Suggests there are clear stages of sleep.

Eastman et al (1998)

Lightboxes relieve symptoms in up to 69% of SAD sufferers.
Placebo effect identified in 30% of sufferers.
Casts doubt on chemical influence of phototherapy.

Endogenous pacemakers

Mechanisms within the body that govern the internal, biological bodily rhythms

Suprachiasmatic Nucleus (SCN)

Tiny bundle of nerve cells located in the hypothalamus.
Primary endogenous pacemakers.
Lies just above the optic chiasm and receives information about light from it.

DeCoursey et al (2000)

Destroyed SCN connections in 30 chipmunks then returned them to their natural habitat and observed for 80 days.
Sleep/wake cycles disappeared and most of them were killed by predators.

Ralph et al (1990)

Bred mutant hamsters with a 20hour sleep/wake cycle. Transplanted SCN cells into normal hamsters + observed how they adjusted to have a 20 hours sleep/wake cycle.

Exogenous zeitgeber

An environmental cue, such as light, that helps to regulate the biological clock in an organism.

Campbell and Murphy (1998)

15 participants woken at various times and torch shone on the back of their knees. Managed to produce a deviation in their sleep/wake cycle of up to 3 hours.

Social Cues

Babies rhythms are entrained by bedtimes and mealtimes
BUT they cry when hungry or sleepy

Damiola et al (2000)

Changing feeding patterns in micr could alter the circadian rhythms of cells in the liver by up to 12hours without affecting the SCN.
Suggests other complex influences on sleep/wake cycle.

Miles et al (1997)

Man blind from birth with circadian rhythm of 24.9 hours. Social cues could not affect his sleep/wake cycle.
Suggests exogenous zeitgebers have little influence on our internal rhythm.

Interactionism

Endogenous pacemakers and exogenous zeitgebers interact in real life so it makes little sense to separate the two for research