Chapter 6: Biopsychology Flashcards
what is the nervous system?
a specialised network of cells and our primary communication system. it is divided into the central nervous system and the peripheral nervous system.
what are the two main functions of the nervous system?
to collect, process and respond to information in the environment.
to coordinate the working of different organs and cells in the body.
what is the central nervous system (CNS) made up of?
the brain and the spinal cord.
what is the brain and its function in the CNS?
the brain is the centre of all conscious awareness.
the outer layer of the brain which is the cerebral cortex is highly developed in humans and is what distinguishes our higher mental functions from those of animals.
what is the spinal cord and its function in the CNS?
the spinal cord is an extension of the brain and is responsible for reflex actions.
it passes messages to and from the brain and connects nerves to the peripheral nervous system (PNS).
what is the peripheral nervous system (PNS) made up of?
it is subdivided into the autonomic nervous system (ANS) and the somatic nervous system (SNS).
what is the function of the PNS?
the peripheral nervous system transmits messages, via millions of neurons, to and from the nervous system.
what is the function of the autonomic nervous system?
the ANS governs vital functions in the body, such as breathing, heart rate, digestion, sexual arousal and stress responses.
it can also be subdivided into the sympathetic nervous system and the parasympathetic nervous system.
what is the function of the somatic nervous system?
the SNS controls muscle movement and receives information from the sensory receptors.
what is the function of the parasympathetic nervous system?
parasympathetic nervous system – calms the body to conserve and maintain energy. e.g. slows down heart rate. ‘rest and digest’
what is the function of the sympathetic nervous system?
sympathetic nervous system – arouses the body to expend energy. neurones from the SNS travel to virtually every organ/gland in the body, in case of rapid action being needed when under threat. ‘fight or flight’
What is the role of the endocrine system?
The endocrine system works alongside the nervous system to control vital functions in the body through the action of hormones.
How does the speed of the endocrine system compare to the nervous system?
The endocrine system works much more slowly than the nervous system but has widespread and powerful effects.
What are glands in the context of the endocrine system?
Glands are organs in the body that produce hormones.
What is the major endocrine gland and its function?
The major endocrine gland is the pituitary gland, located in the brain. It is called the ‘master gland’ because it controls the release of hormones from all the other endocrine glands in the body.
What are hormones?
Hormones are secreted in the bloodstream and affect any cell in the body that has a receptor for that particular hormone.
Can you provide an example of a hormone and its effect?
Thyroxine produced by the thyroid gland affects cells in the heart and also cells throughout the body which increase metabolic rates. This in turn affects growth rates.
How do the endocrine system and the ANS work together?
The endocrine system and the ANS often work in parallel, for instance during a stressful event.
What happens when a stressor is perceived?
The hypothalamus triggers activity in the sympathetic branch of the ANS, changing from its normal resting state to the physiologically aroused sympathetic state.
What hormone is released during the fight or flight response?
The stress hormone adrenaline is released from the adrenal medulla into the bloodstream.
What physiological changes does adrenaline trigger?
Adrenaline triggers physiological changes in target organs in the body, causing increased heart rate, dilation of the pupils, and decreased production of saliva.
What happens after the threat has passed?
The parasympathetic nervous system returns the body to its resting state, sometimes referred to as the ‘rest and digest’ response.
What is the total number of neurons in the human nervous system?
There are 100 billion nerve cells (neurons) in the human nervous system, 80% of which are located in the brain.
What are the primary means of communication in the nervous system?
Neurons transmit signals electrically and chemically.
What are the three types of neurons?
- Motor neurons
- Sensory neurons
- Relay neurons
What is the function of motor neurons?
Motor neurons connect the CNS to effectors such as muscles and glands.
What is the structure of motor neurons?
Motor neurons have short dendrites and long axons.
What is the function of sensory neurons?
Sensory neurons carry messages from the PNS to the CNS.
What is the structure of sensory neurons?
Sensory neurons have long dendrites and short axons.
What is the function of relay neurons?
Relay neurons connect sensory neurons to motor or other relay neurons.
What is the structure of relay neurons?
Relay neurons have short dendrites and short axons.
What are the basic structures shared by all neurons?
- Cell body (or soma)
- Dendrites
- Axon
What does the cell body of a neuron contain?
The cell body includes a nucleus which contains the genetic material of the cell.
What is the function of dendrites?
Dendrites carry nerve impulses from neighbouring neurons towards the cell body.
What is the function of the axon?
The axon carries the electrical impulse away from the cell body down the length of the neuron.
What is the myelin sheath?
The myelin sheath is a fatty layer that covers the axon and protects it.
What are the nodes of Ranvier?
Gaps in the axon that speed up the transmission of the impulse.
What are terminal buttons?
Terminal buttons at the end of the axon communicate with the next neuron in the chain across a gap called the synapse.
What is the charge of a neuron in a resting state?
The inside of the cell is negatively charged compared to the outside.
What happens when a neuron is activated?
The inside of the cell becomes positively charged for a split second, causing an action potential to occur.
What does an action potential create?
An action potential creates an electrical impulse that travels down the axon towards the end of the neuron.
What is a synapse?
A tiny gap that separates each neuron from the next.
How are signals transmitted within neurons?
Signals within neurons are transmitted electrically.
How are signals transmitted between neurons?
Signals between neurons are transmitted chemically across the synapse.
What triggers the release of neurotransmitters?
The arrival of an electrical impulse at the presynaptic terminal triggers the release of neurotransmitters from synaptic vesicles.
What happens after neurotransmitters cross the synapse?
They are taken up by the postsynaptic receptor site on the next neuron, converting the chemical message back into an electrical impulse.
What are neurotransmitters?
Chemicals that diffuse across the synapse to the next neuron.
What is the lock and key model in neurotransmission?
Each neurotransmitter has a specific molecular structure that fits perfectly into a postsynaptic receptor site.
What is the function of Acetylcholine (ACh)?
It is found where a motor neuron meets a muscle, causing muscles to contract.
What role does serotonin play?
It affects mood and social behavior and has been implicated as a cause of depression.
What is the effect of adrenaline on neurons?
Generally excitatory, increasing the positive charge of the postsynaptic neuron.
What is the effect of serotonin on neurons?
Generally inhibitory, increasing the negative charge of the postsynaptic neuron.
What is unique about dopamine?
It can have either excitatory or inhibitory effects on the next neuron.
What is summation in neurotransmission?
Excitatory and inhibitory influences are summed and must reach a certain threshold to trigger the action potential.
What happens if the net effect of neurotransmitters is inhibitory?
The postsynaptic neuron is less likely to fire.
What happens if the net effect of neurotransmitters is excitatory?
The postsynaptic neuron is more likely to fire.
What is the holistic theory of brain function?
The holistic theory suggests that all parts of the brain are involved in processing thought and action.
What is the localisation theory in the brain?
The localisation theory links specific areas of the brain with specific physical and psychological functions.
What happens if an area of the brain is damaged?
If an area of the brain is damaged through illness or injury, the function associated with that area is also affected.
How is the brain divided?
The brain is divided into two halves: the left and right hemispheres.
What is lateralisation in the brain?
Lateralisation refers to the control of some physical and psychological functions by a particular hemisphere.
Which hemisphere controls the left side of the body?
The right hemisphere controls the left side of the body.
Which hemisphere controls the right side of the body?
The left hemisphere controls the right side of the body.
What is the outer layer of the brain called?
The outer layer of the brain is called the cerebral cortex.
How many lobes is the cerebral cortex divided into?
The cortex of both hemispheres is divided into four lobes: frontal, parietal, occipital, and temporal.
What is the function of Broca’s area?
Broca’s area is responsible for speech production.
What is the function of Wernicke’s area?
Wernicke’s area is responsible for language comprehension.
What is the thickness of the cerebral cortex?
The cerebral cortex is about 3 mm thick.
Why does the cortex appear grey?
The cortex appears grey due to the location of cell bodies, hence the phrase ‘grey matter’.
Where is the motor area located?
The motor area is located at the back of the frontal lobe in both hemispheres.
What does the motor area control?
The motor area controls voluntary movement.
What is the function of the somatosensory area?
The somatosensory area processes sensory information from the skin (touch, heat, pressure, etc.).
Where is the visual area located?
The visual area is located in the occipital lobe at the back of the brain.
How does visual information travel from the eyes to the brain?
Each eye sends information from the right visual field to the left visual cortex, and from the left visual field to the right visual cortex.
What happens if the left hemisphere is damaged?
Damage to the left hemisphere can produce blindness in the right visual field of both eyes.
Where is the auditory area located?
The auditory area is located in the temporal lobe.
What does the auditory area analyse?
The auditory area analyses speech-based information.
What is Broca’s aphasia?
Broca’s aphasia is caused by damage to Broca’s area, resulting in slow, laborious speech that lacks fluency.
What difficulties do patients with Broca’s aphasia face?
Patients with Broca’s aphasia have difficulty finding words and naming certain objects.
What types of words do patients with Broca’s aphasia struggle with?
Patients have difficulty with prepositions and conjunctions (e.g., ‘a’, ‘the’, ‘and’).
What is Wernicke’s aphasia?
Wernicke’s aphasia is caused by damage to Wernicke’s area, leading to fluent but meaningless speech.
What do patients with Wernicke’s aphasia produce?
Patients often produce nonsense words (neologisms) as part of their speech.
What is plasticity in the brain?
Plasticity refers to the brain’s ability to form and prune synaptic connections.
What happens to synaptic connections during infancy?
The brain experiences rapid growth in synaptic connections, peaking at about 15,000 at age 2-3 years.
What is synaptic pruning?
Synaptic pruning is the process where rarely used connections are deleted and frequently used connections are strengthened.
Is plasticity limited to childhood?
No, recent research suggests that neural connections can change or be formed at any time due to learning and experience.
What did Maguire et al. (2000) find regarding London taxi drivers?
They found significantly more volume of grey matter in the posterior hippocampus of taxi drivers compared to a matched control group.
What is ‘The Knowledge’ test?
‘The Knowledge’ is a complex test taken by London cabbies to assess their recall of city streets and possible routes.
What did Draganski et al. (2006) study in medical students?
They imaged the brains of medical students three months before and after final exams, observing learning-induced changes.
What is functional recovery of the brain after trauma?
It is when unaffected areas of the brain take over lost functions, demonstrating neural plasticity.
What occurs during spontaneous recovery after brain trauma?
Neuroscientists suggest that recovery occurs quickly after trauma and then slows down, often requiring rehabilitative therapy.
How does the brain ‘rewire’ itself?
The brain rewires itself by forming new synaptic connections close to the area of damage.
What are some structural changes that may occur in the brain?
Structural changes may include axonal sprouting, reformation of blood vessels, and recruitment of homologous areas on the opposite side of the brain.
What is axonal sprouting?
Axonal sprouting is the growth of new nerve endings that connect with other undamaged cells to form new neuronal pathways.
What is split-brain research?
Split-brain research involves studying individuals who have undergone a commissurotomy to understand hemispheric lateralisation.
What is hemispheric lateralisation?
Hemispheric lateralisation refers to the specialization of the two hemispheres of the brain for certain functions.
Who devised the procedure for split-brain studies?
Sperry devised a unique procedure to test his split-brain patients.
What is a commissurotomy?
A commissurotomy is an operation to cut the corpus callosum, sometimes performed to control epileptic seizures.
What happens when an image is projected to the RVF?
When an image is projected to the RVF, the patient easily describes what is seen.
What happens when an image is projected to the LVF?
When an image is projected to the LVF, the patient says ‘there’s nothing there’ because the RH usually lacks language centres.
How can a patient respond to objects shown in the LVF?
The patient could not name the objects but could select a matching object using their left hand.
What is an example of composite words in split-brain studies?
If ‘key’ is presented to the left and ‘ring’ to the right, the patient selects a key with their left hand and says ‘ring’.
What occurs when a composite picture of two different halves of a face is presented?
The LH dominates the verbal description while the RH dominates the selection of a matching picture.
What is the purpose of scanning in psychological research?
The purpose of scanning is often to investigate localisation - to determine which parts of the brain do what.
What does fMRI stand for?
Functional magnetic resonance imaging (fMRI) detects changes in blood oxygenation and flow due to neural activity.
How does fMRI indicate brain activity?
When a brain area is more active, it consumes more oxygen and blood flow is directed to that area (haemodynamic response).
What does MRI produce?
MRI produces a 3D image showing which parts of the brain are active and involved in particular mental processes.
What does EEG stand for?
Electroencephalogram (EEG) measures electrical activity within the brain via electrodes using a skull cap.
What does an EEG recording represent?
The scan recording represents the brainwave patterns generated from millions of neurons, showing overall brain activity.
What is EEG often used for?
EEG is often used as a diagnostic tool for abnormalities such as epilepsy, tumours, or sleep disorders.
What are Event-related potentials (ERPs)?
ERPs are what is left when extraneous brain activity from an EEG recording is filtered out.
How are ERPs related to cognitive processes?
ERPs are types of brainwave triggered by particular events and linked to cognitive processes like perception and attention.
What are post-mortem examinations?
A technique involving the analysis of a person’s brain following their death to establish the likely cause of a deficit or disorder.
What may post-mortem examinations involve?
They may involve comparison with a neurotypical brain to assess the extent of the difference.
What are circadian rhythms?
Biological rhythms governed by endogenous pacemakers and exogenous zeitgebers.
How long does a circadian rhythm last?
The circadian rhythm lasts for about 24 hours.
What internal and external mechanisms govern the sleep/wake cycle?
The sleep/wake cycle is governed by internal biological ‘clocks’ (endogenous pacemakers) and external changes in the environment (exogenous zeitgebers).
What did Siffre demonstrate about free-running circadian rhythms?
Siffre demonstrated a free-running circadian rhythm of about 25 hours.
What did Aschoff and Wever find regarding circadian rhythms?
Aschoff and Wever also found a similar circadian rhythm.
Which has a stronger influence on circadian rhythms: endogenous pacemakers or exogenous zeitgebers?
Endogenous pacemakers may have a stronger influence than exogenous zeitgebers.
What are the types of biological rhythms?
Biological rhythms include ultradian rhythms (occur many times a day), infradian rhythms (take less than a day to complete), and circannual rhythms (take much longer).
What does ‘circadian’ mean?
‘Circadian’ means ‘about’ (circa) ‘day’ (diem).
What is an example of a circadian rhythm?
The sleep/wake cycle is an important type of circadian rhythm.
What is an exogenous zeitgeber?
Exogenous zeitgebers are external cues, like daylight, that influence our sleep/wake cycle.
What is an endogenous pacemaker?
An endogenous pacemaker is a biological clock left to its own devices without external stimuli, known as ‘free-running.’
What is the role of the suprachiasmatic nucleus (SCN) in circadian rhythms?
The SCN governs a basic rhythm and receives light information directly.
How can light act as an exogenous zeitgeber?
Light can reset the SCN.
What did Siffre’s studies in dark caves reveal?
Siffre’s studies showed that his free-running circadian rhythm settled to just above 24 hours (about 25 hours) while maintaining a regular sleep/wake cycle.
What was the outcome of the World War 2 bunker study?
Participants displayed a circadian rhythm between 24 and 25 hours, suggesting a natural sleep/wake cycle slightly longer than 24 hours.
What did Folkard et al. (1985) study reveal about circadian rhythms?
Only one participant adjusted to a 22-hour day, suggesting a strong free-running circadian rhythm that is hard to override.
What is an example of an infradian rhythm?
The female menstrual cycle is an infradian rhythm.
What may synchronize menstrual cycles?
Exogenous zeitgebers may synchronize menstrual cycles.
What is Seasonal Affective Disorder (SAD)?
SAD is a depressive disorder with a seasonal pattern.
What hormone may cause SAD?
SAD may be caused by the hormone melatonin.
How long is the human female menstrual cycle?
The human female menstrual cycle is about 28 days.
What happens during ovulation?
Rising levels of estrogen cause the ovary to develop and release an egg.
What occurs if pregnancy does not happen?
The egg is absorbed into the body and the womb lining comes away, resulting in menstrual flow.
What did Stern and McClintock (1998) study?
They studied 29 women with irregular periods and found that 68% experienced changes to their cycle.
What is the effect of light on melatonin secretion during winter?
The lack of light in the morning means melatonin secretion goes on for longer.
What are ultradian rhythms?
Ultradian rhythms are cycles that occur more than once in 24 hours.
What is the sleep pattern duration?
Sleep patterns occur in 90-minute periods.
How many stages of sleep have been identified?
Five stages of sleep have been identified.
What characterizes stages 1 and 2 of sleep?
Stages 1 and 2 are light sleep where the person may be easily woken.
What characterizes stages 3 and 4 of sleep?
Stages 3 and 4 are deep sleep characterized by delta waves.
What occurs during stage 5 of sleep?
Stage 5 is REM sleep, where there is fast eye movement and increased brain activity.
What is the SCN?
The suprachiasmatic nucleus (SCN) is a tiny bundle of nerve cells in the hypothalamus which helps maintain circadian rhythms (e.g. sleep/wake cycle).
What are endogenous pacemakers?
Endogenous pacemakers are internal mechanisms that regulate biological rhythms.
How does the SCN influence the sleep/wake cycle?
The SCN passes information on day length to the pineal gland which increases production of melatonin during the night.
What is melatonin?
Melatonin is a hormone that induces sleep and is inhibited during periods of wakefulness.
It has also been suggested as a causal factor in seasonal affective disorder.
What was demonstrated in DeCoursey et al. (2000)?
DeCoursey et al. destroyed SCN connections in the brains of 30 chipmunks, which led to their sleep/wake cycle disappearing and many being killed by predators.
What did Ralph et al. (1990) discover?
Ralph et al. bred ‘mutant’ hamsters with a 20-hour sleep/wake cycle, and SCN cells transplanted from these hamsters into normal hamsters resulted in 20-hour cycles.
What are exogenous zeitgebers?
Exogenous zeitgebers are external environmental factors that reset biological clocks.
What does the term zeitgeber mean?
The German word zeitgeber means ‘time giver’.
What is the process of resetting biological clocks called?
Resetting biological clocks is known as entrainment.
What is a key exogenous zeitgeber that influences the sleep/wake cycle?
Light is a key exogenous zeitgeber that influences the sleep/wake cycle.
How does light influence the SCN?
Light can reset the body’s main endogenous pacemaker (SCN) and influences key processes in the body controlling hormone secretion, blood circulation, etc.
What did Campbell and Murphy (1998) find?
Campbell and Murphy woke 15 participants at various times and shone a light on the backs of their knees, producing a deviation in the sleep/wake cycle of up to three hours.
How do social cues influence the sleep/wake cycle?
Schedules imposed by parents, including adult-determined mealtimes and bedtimes, are a key influence on the sleep/wake cycle.
When do most babies become entrained to the sleep/wake cycle?
Most babies are entrained by about six weeks.
What helps tackle jet lag?
Adapting to local times for eating and sleeping helps entrain circadian rhythms and tackle jet lag.
