Psych Unit 3/4

Central nervous system

Composed of the brain and spinal cord. Carries messages to and from the PNS.

Peripheral nervous system

Composed of the autonomic and somatic nervous systems. Carries message to and from the CNS.

Brain

Responsible for everything we think, feel, and do.

Spinal cord

Connects the brain to the PNS; initiates spinal reflexes.

Somatic NS

Carries messages from sensory receptors in the body to the CNS, and motor messages from the CNS to skeletal muscles.

Autonomic NS

Connects CNS to internal organs and glands; self-regulating. Made up of the sympathetic, parasympathetic, and enteric nervous systems.

Sympathetic NS

Prepares the body for action.

Parasympathetic NS

Calms body after action.

Enteric NS

Dedicated to the functioning of the gastrointestinal tract.

Conscious responses

• can be learned

• mostly uses the somatic NS

• can be complex or simple responses

• tend to vary (inconsistent)

• requires attention to be paid to the stimulus

• goal-directed

Unconscious response

• first occur without learning

• mostly uses the autonomic NS

• usually simple responses

• tend to occur in the same way every time

• doesn’t require attention for it to occur

• purpose is to increase chances of survival

Spinal reflex

An unconscious, involuntary, and automatically occurring response to certain stimuli initiated within the spinal cord without any involvement of the brain.

Often referred to as a ‘reflex arc’.

Receptor cells

Typically detect external stimuli.

Motor neurons

Efferent; central → peripheral.

Sensory neurons

Afferent; peripheral → central.

Interneuron

Only in the CNS.

Dendrites

Branches of a neuron that receive information from other neurons.

Axon

A long extension that transmits neural information in the form of action potentials (electrical activity).

Myelin sheath

An insulating layer made of a white fatty substance, that allows for efficient transmission of information.

Axon terminals

Branches that allow one neuron to send information to many others.

Synaptic buttons

Knobs at the end of axon terminals that release neurotransmitters.

Neurotransmitter

A chemical substance produced by a neuron that carries a message to other neurons, by attaching to receptors sites on postsynaptic neurons that are specialised for that specific neurotransmitter.

Can have either an excitatory or inhibitory effect on the postsynaptic neuron.

Glutamate

The main excitatory neurotransmitter in the CNS → makes postsynaptic neurons more likely to fire.

Its release is associated with learning and memory.

Gamma-aminobutyric acid (GABA)

The main inhibitory neurotransmitter in the CNS → makes postsynaptic neurons less likely to fire.

Helps maintain levels of neural activity.

Neuromodulator

Changes the reactivity of receptors to another type of neurotransmitter to enhance their excitatory or inhibitory response.

Are released into broader areas, and thus affects many neurons at once, but have a slower effect than neurotransmitters.

Dopamine

Has important roles in:

• voluntary movements

• the experience of pleasure

• motivation

• appetite

• reward-based learning and memory

Also implicated in:

• Parkinson’s disease

• addiction

• schizophrenia

Serotonin

Has important roles in:

• mood

• emotional processing

• sleep onset

• appetite

• pain perception

Synaptic plasticity

The ability of the synapse to change in response to experience.

Sprouting

The creation of new extensions on a neuron to allow it to make new connections with other neurons.

Rerouting

Occurs when new connections are made between neurons to create an alternate neural pathway.

Pruning

The elimination of weak, ineffective, or unused synapses (and therefore connections to other neurons).

Long-term potentiation

The long lasting enhancement of synaptic transmissions due to repeated, strong stimulation.

Long-term depression

The long lasting decrease in the strength of synaptic transmissions and neuronal response due to a lack of use.

Stress

A state of physiological and psychological arousal produced by internal and external stressors that are perceived by the individual as challenging or exceeding their ability or resources to cope.

Stressors

Stimuli that cause or produce stress, and challenge the individual’s ability to cope.

Internal stressor

Originate within the individual.

External stressors

Originates outside the individual from situations and events in the environment.

Acute stress

Stress that lasts for a relatively short time → fight/flight/freeze response.

Chronic stress

Stress that continues for a prolonged period of time → release of cortisol.

Fight-flight-freeze response

An involuntary response to a sudden and immediate threat/stressor in readiness to:

• fight → confront and fight off the threat

• flight → escape by running away to safety

• freeze → avoid detection by remaining absolutely still and silent

All three are considered adaptive responses that enable us to deal with the threat at hand and help minimise harm.

Fight-flight physiological symptoms

Release of adrenaline and noradrenaline cause:

• increased heart rate and blood pressure

• increased breathing rate

• dilation of pupils

• muscles tense

• suppression of functions that aren’t immediately essential in order to preserve energy

Freeze physiological symptoms

• body movements and vocalisations stop

• decreased heart rate and breathing

• blood pressure drops significantly (can cause fainting)

• muscles relax

Cortisol

Considered the main stress hormone; it is slow acting, and has long lasting effects, which help keep the body at an elevated level of arousal.

The gut-brain axis (GBA)

A bidirectional communication link between the central and enteric nervous systems.

Vagus nerve

Connects cognitive and emotional regions of the brain to the intestinal tract via a collection of sensory and motor neurons.

Selye’s General Adaptation Syndrome

A biological model of stress → a 3-stage (S.C.A.R.E.) physiological response to stress that occurs regardless of the stressor that is encountered.

Strengths:

• explains both immediate and long-term effects of stress

• connection between stress and disease

Limitations:

• is a “one size fits all” model

• primarily based on animal research

Lazarus and Folkman’s Transactional Model of Stress and Coping

The individual’s interpretation of the situation determines whether a stress response occurs and how they cope.

Strengths:

• explains why different people respond in different ways to the same types of stressors

• focuses on psychological determinants of stress response over which we have control

Limitations:

• we can experience a stress response without having thought about the situation (shows that appraisal is not necessary)

• difficult to experimentally test, as it is subjective

• overlooks the physiological responses to a stressor

Context-specific effectiveness

Refers to a “good match” between a coping strategy and the stressful situation.

Coping flexibility

The ability to effectively modify or adjust one’s coping strategies to suit the demands of different stressful situations.

Approach coping strategies

• activity is focused towards the stressor

• deals with the underlying problem

• engagement with the stressor

• adaptive

Avoidant coping strategies

• activity focused away from the stressor

• no attempt to confront the stressor and its causes

• disengagement from the stressor

• maladaptive

Learning

A relatively permanent change in behaviour that occurs as a result of experience → can occur intentionally or unintentionally.

Behaviourist approach

Emphasises the study of observable behaviour alone to understand and explain learning, without regard to underlying mental processes.

Classical conditioning (key terms)

• before/during/after conditioning

• neutral stimulus

• unconditioned stimulus

• unconditioned response

• conditioned stimulus

• conditioned response

Factors that influence C.C.

• nature of the response → UCR must be an automatic/involuntary response

• association of stimuli

• timing of NS and UCS pairing

Operant conditioning (key terms)

• antecedent

• behaviour

• consequence

• positive/negative reinforcement/punishment

Factors that influence O.C.

• order of presentation → consequence occurs after the response

• timing → consequence is immediate

• appropriateness → reinforcer must actually be desired, and punisher actually be unpleasant

Social cognitive approach

Emphasises the social context in which learning occurs, and the cognitive processes that influence the individual and the learning process → that learning can be done vicariously.

Observational learning (key terms)

• model (live or symbolic)

• attention

• retention

• reproduction

• motivation - reinforcement

Situated multimodal system of learning

Recognises that the culture we grow up in, the landscapes that surround us, and the languages we speak strongly influence how we come to understand the universe and our place in it.

Memory

The processing, storage, and retrieval of information acquired through learning.

incoming sensory info → encoding → storage ⇄ retrieval

Sensory memory

Where new, incoming sensory info is stored in its original, raw state for a very brief time; we are not consciously aware of this info.

Short term memory

Where info is stored for a relatively short time, unless renewed in some way. It also maintains info in conscious awareness and functions as ‘working memory’.

Long term memory

Stores a potentially unlimited amount of info for a very long time after original learning → possibly permanently.

Explicit memory

LTM that can be consciously retrieved and stated → episodic or semantic.

Implicit memory

LTM that doesn’t require conscious or intentional retrieval → procedural or classically conditioned.

Alzheimer’s disease

A type of dementia characterised by the gradual, widespread degeneration of brain neurons.

Characterised by high levels of abnormal structures at a neuronal level → amyloid plaques ad neurofibrillary tangles.

Aphantasia

A disorder characterised by an inability to conjure mental imagery.

Acronym

Pronounceable words formed from the first letters of a group of words to be remembered.

Acrostic

Making verbal associations for words to be remembered by constructing phrases, where the first letter of each words to be remembered corresponds to the first letter of a word in the phrase, acting as a retrieval cue.

Method of loci

A mnemonic device where the item to be remembered are converted into a mental image and associated with specific locations.

Songline

A route composed of a sequence of locations, where at each, a story, song, dance, or ceremony may be performed, communicating certain information, so that the information is associated with the specific location.

Hippocampus

Encodes and consolidates explicit memories for transfer to long-term storage.

Neocortex

Stores long-term explicit memories.

Amygdala

Enhances the encoding and consolidation of emotional memories.

Basal ganglia

Involved in procedural learning.

Cerebellum

Involved in conditioned responses and motor learning.

Consciousness

A psychological construct → our awareness of the external and internal world. It is:

• personal

• selective

• continuous

• changing

Normal waking consciousness

Associated with being awake and aware of objects and events in the external world, and of one’s sensations, mental experiences, and own existence.

Altered state of consciousness

A state of awareness that is distinctly different from normal waking consciousness in terms of level of awareness and experience → can be natural or induced.

Sleep

A regularly occurring altered state of consciousness that typically occurs naturally and is primarily characterised by partial or total suspension of conscious awareness.

Electroencephalograph (EEG)

Detects, amplifies, and records general patterns of electrical activity in the brain.

Electromyograph (EMG)

Detects, amplifies, and records electrical activity of muscles → shows changes in muscle activity and tone.

Electro-oculograph (EOG)

Detects, amplifies, and records electrical activity in eye muscles that control eye movements.

Sleep diaries

A log used to self-record and self-report sleep and waking time activities over a period of time.

Video monitoring

Video cameras which monitor and record externally observable physiological responses throughout a sleep episode.

Biological rhythms

Naturally occurring patterns of cyclic changes in a bodily function or state that repeats itself over a period of time → maintained and controlled by an internal mechanism or neural system.

Circadian rhythm

A biological cycle that goes over a period of approximately 24 hours.

Ultradian rhythm

A biological cycle that goes over a period of less than 24 hours.

Suprachiasmatic nucleus (SCN)

An area of the brain’s hypothalamus that regulates the timing and activity of the sleep-wake cycle (and other biological rhythms).

Melatonin

A hormone involved in the intiation of sleep and in the regulation of the sleep-wake cycle.

Pineal gland

Produces and secretes melatonin into the bloodstream when signalled to by the SCN.

nREM

Makes up about 75-80% of total sleep time. Is characterised by the gradual reduction of physiological activity from stage 1 to 3.

nREM stage 1

A period of relatively light sleep → 4-5% of total sleep time.

May experience hypnic jerks (muscle twitches) as muscles begin to relax.

nREM stage 2

A period of light-moderate sleep → 50% of total sleep time.

May observe sleep spindles (brief bursts of electrical activity in the brain) → their presence indicates transition into this stage.

More time spent in this stage as the sleep period progresses.

Typically precedes the first REM period.

nREM stage 3

A period of deep sleep → 10-15% of total sleep time.

Less time spent in this stage as the sleep period progresses.

REM

Makes up around 20-25% of total sleep time.

REM periods lengthen and occur closer together as the sleep period progresses.

Shares the properties of both light and deep sleep → paradoxical.

Changes in sleep across ages

From infancy → elderly:

• less time spent sleeping altogether

• less time spent in REM sleep

• more time spent in nREM sleep

• gradual loss of nREM stage 3 across late adulthood and elderly

• sleep becomes lighter overall

Sleep deprivation

A state caused by inadequate quantity and quality of sleep.

Total sleep deprivation

Involves not having any sleep at all over a short or long term.