Psychology-Biopsychology Flashcards
(204 cards)
1
Q
What is brain plasticity?
A
It refers to the brain’s ability to modify its own structure and function as a result of experience
2
Q
What is functional recovery?
A
It refers to the recovery of abilities and mental processes that have been compromised as a result of brain injury or disease
3
Q
What factors are known to affect plasticity?
A
Life experience, playing video games and meditation
4
Q
How can life experience affect plasticity?
A
New experiences mean nerve pathways that are frequently used develop stronger connections, whereas neurones that are rarely or never used eventually die, eg Maguire (posterior hippocampus), Rosenzweig and Bennet (cerebral cortex), Perry (cerebral cortex), and Boyke (teaching 60 year olds to juggle)
5
Q
How can playing video games affect plasticity?
A
It makes many different complex cognitive and motor demands. Kuhn found that playing video games for 30 minutes a day for two months had increased grey matter in brain areas including the cortex, hippocampus and cerebellum as the games led to new synaptic connections
6
Q
How can meditation affect plasticity?
A
Davidson et al compared Tibetan meditation practitioners and volunteers with no meditation experience. Whilst meditating, the monks had much greater activation of gamma rays (coordinate neurone activity), whilst the volunteers only had a slight increase. Meditation has short and long term affects on brain workings
7
Q
What are three evaluation points on plasticity?
A
Implications for real life (Boyke), application of research (support studies), and methodology eg animal studies
8
Q
What are two mechanisms for functional recovery after trauma?
A
Neuronal unmasking and stem cells
9
Q
What is neuronal unmasking?
A
Wall identified dormant synapses in the brain which are not active, but can be activated when the neural input increases due to a surrounding brain area becoming damaged or unmasked. Unmasking dormant synapses can open connections to regions of the brain which are not normally active, creating a lateral spread of activation which, in time, can give way to the development of new structures
10
Q
When was the localisation of brain function discovered?
A
In the 19th century
11
Q
What is the definition of localisation?
A
Theory that specific areas of the brain are associated with particular physical and psychological functions
12
Q
How is the brain divided?
A
Into two hemispheres (left and right) and each is responsible for specific functions
13
Q
What is the general rule for the hemispheres?
A
Activity on the left hand side of the body is controlled by the right hemisphere. Activity on right hand side of the body is controlled by the left hemisphere
14
Q
What is cerebral cortex?
A
The outer layer of both hemisphere, about 3mm thick, It is what separates humans from other animals because the human cortex is much more developed
15
Q
What are the six parts of the brain looked at in this section?
A
The motor cortex, the somatosensory cortex, Wenicke’s area, the visual cortex, the auditory cortex, and Broca’s area
16
Q
What parts of the brain are used for movement and touch?
A
The motor cortex and the somatosensory cortex
17
Q
What is the motor cortex responsible for?
A
The generation of voluntary motor movements (not reflexes)
18
Q
Where is the motor cortex located?
A
In the frontal lobe, in area called the pre-central gyrus
19
Q
Which hemisphere have a motor cortex?
A
Both hemispheres. One side of the motor cortex controls the opposite side of the body
20
Q
How are the regions attached?
A
Logically. The area which controls the foot is next to the area which controls the leg etc
21
Q
What is the somatosensory cortex responsible for?
A
Detecting sensory events related to touch from different regions of the brain
22
Q
Where is the somatosensory cortex located?
A
In the parietal lobe, in an area called the post-central gyrus
23
Q
Which hemisphere has a somatosensory cortex?
A
Both-one side of the somatosensory cortex receives sensory information for the opposite side of the body
24
Q
What somatosensory cortex produce?
A
Sensations of touch, pressure, pain and temperature which are localised to specific body regions
25
What parts of the brain are used for sight and sound?
The visual cortex and the auditory cortex
26
What does the visual cortex do?
It has several different areas, with each of the areas processing different types of visual information, such as colour, shape or movement
27
Where is the visual cortex located?
In the occipital lobe, in an area called the visual cortex ?
28
Which hemisphere contains the visual cortex?
Both-one side of the visual cortex receives information from the visual field from the opposite side of the body
29
How does visual information travel to the visual cortex?
Nerve impulse from retina to the optic nerve to the brain, to the thalamus, to the visual cortex
30
What is the auditory cortex responsible for?
Sound and producing an appropriate response
31
Where is the auditory cortex located?
In the temporal lobe in the auditory cortex?
32
Which hemisphere has a auditory cortex?
Both however information doesn't swap hemispheres in a clear cut manner
33
How does auditory travel to the auditory cortex?
Sound waves to nerve impulses, to auditory nerve, to brain stem for decoding, to thalamus for processing, to the auditory cortex
34
What parts of the brain are used language?
Broca's area and Wernicke's area
35
What is Broca's area responsible for?
Speech production-both verbally and internally (affecting expression thoughts in area)
36
Where is Broca's area located?
In the frontal lobe of the left hemisphere in an area known as the Broca's area?
37
Why is it called Broca's area?
After Paul Broca who studied Tan in 1861-called 'tan' as that was the only syllable he could express, but could understand spoken language
38
Since 2012 psychologists also believe what about Broca's area?
Parts of it is also used in demanding cognitive tasks
39
What is damage Broca's area is know as?
Broca's aphasia
40
What is Wernicke's area responsible for?
Comprehending language-speech is typically fluent but is empty of content in Wernicke's aphasia
41
Where is Wernicke's area located?
In the left posterior temporal lobe, in an area known as Wernicke's area?
42
What did Carl Wernicke study?
Aphasia 1874
43
What has also been found out about Wernicke's area?
It is close to regions of the brain responsible for auditory and visual input-where information should be recognised with language and associated with meaning
44
What are the strengths of localised function theory?
There is support for language centres from aphasia studies (expressive aphasia-Broca's aphasia, and receptive aphasia-Wernicke's aphasia)
45
What are the limitations of localised function theory?
Conflicting theory (equipotentiality-Lashley), communication between brain areas may be more important than localisation (Dejerine), Individual differences in language areas (Bavelier et al), and Language production may not be confined to Broca's area alone (Dronkers et al)
46
What is hemispheric lateralisation?
Some mental processes in the brain are mainly specialised to either the right or left hemisphere
47
What are examples of hemispheric lateralisation?
Language is in the left hemisphere, and facial recognition is in the right hemisphere
48
What is the corpus callosum?
A bunch of nerve fibres that join the two lobes of the brain, so that, for example, you can see something in your left eye, have it register in your left hemisphere, and then talk about it from the left hemisphere
49
What is a split brain patient?
Some patients with epilepsy have the nerve fibres cut, to stop the seizures passing between hemispheres
50
What experiment did Sperry and Gazzniga conduct?
They placed different objects in one visual field at a time and asked the participant what they saw. If a dog was placed in the right visual field it would be picked up by the left hemisphere, if a cat was placed in the left visual field it would be picked up by the right hemisphere
51
What did Sperry and Gazzniga find?
If the dog was placed in the right visual field then participants could say that they could see a dog, but if a cat was in the left visual field, a split brain patient would not be able to say that they could see it
52
Why did Sperry and Gazzniga find the results that they did?
Because language is in the left hemisphere and so when a cat is seen in the left visual field, it goes to the right hemisphere and cannot move to the left (where language is) as their corpus callosum has been cut
53
What are the strengths of lateralisation and split brain research?
Language may not be restricted to the left hemisphere (Gazzniga-JW damaged left hemisphere bit can speak about information in both sides of the brain), and methodological evaluation (Sperry's research was wee designed, had standardised procedures, control and it was replicable)
54
What are the weaknesses of lateralisation and split brain research?
Theoretical evaluation(growing amount of pop-psychology literature concerning the functional distinction between hemispheres, oversimplifies and over emphasises the differences), lateralisation changes with age (lateralised patterns switch to bilateral patterns in older adults in many types of tasks and brain areas) and methodological evaluation (Andrewes-only small amounts of split brain patients exist and so studies are very small, where participants may have a confounding physical disorder)
55
What are biological rhythms?
Cyclical changes in the way biological systems behave
56
What are three biological rhythms?
Circadium (24 hours), ultradian (more than once every 24 hours) and infradian (less than one every 24 hours)
57
What is a circadian rhythm?
Comes from latin (circa=about and dies=a day). It is also known as the 'body clock'. Circadian rhythms are drived by our body clocks, found in all of the cells of the body, which are synchronised by the master circadian pacemaker-the suprachiasmatic nucleus, which is found in the hypothalamus. This pacemaker must constantly be rest to be in synchrony with the outside world
58
What is the nature of circadian rhythms?
Light proves primary input, light sensitive cells in eyes are brightness detectors, send messages about light levels to suprachiasmatic nucleus (SCN), SCN uses this information to co-ordinate activity of the entire circadian system, body clock is set to correct time "photoentrainment"
59
What are sleep and wakefulness determined by?
Circadian rhythms and homeostatic control
60
How do circadian rhythms affect the sleep and wake cycle?
Light and darkness are the external signals that determine when we should be sleeping or feeling awake. There are also dips and rises at different times of the day, ie our strongest sleep drive is between 2-4am and 1-3pm. This sleepiness is less intense if we have had sufficient sleep, and vice versa
61
How does homeostatic control affect the sleep and wake cycle?
When we have been awake for a long time, homeostasis tells us that the need for sleep is increasing due to decreased energy. This homeostatic drive for sleep increases gradually through the day, reaching its maximum in the evening when most people fall asleep. This homeostatic system tends to make us sleepier as time goes on, irrespective of it being night or day
62
The internal circadian 'clock' maintains a cycle of about what?
24-25 hours, even in the absence of external cues, however it is intolerant of any circadian rhythm sleep disorders, either intrinsic eg jet-lag and shift work sleep disorder, or extrinsic eg delayed sleep phase syndrome (common amongst teens who habitually sleep in late
63
What is a case study for circadian rhythms?
Michel Siffre-he lived underground in a cave to study his circadian rhythms. First stay was 61 days until September 17th but he thought it was August 20th. Then stayed for six months and his natural circadian rhythm was just over 24 hours. He stayed again at 60 years old to see the effects of ageing, and his circadian rhythm was about 48 hours
64
What are two other circadian rhythms?
Core body temperature and hormone production
65
Explain core body temperature as a circadian rhythm
Body temperature is lowest at 3:30am and highest at 6pm. Sleep occurs when core body temp begins to drop. It starts to rise during the last hours of sleep, prompting alertness. There is also a small drop at 2-4pm which explains afternoon tiredness
66
Explain hormone production as a circadian rhythm
Melatonin is a hormone produced by the pineal gland and controls sleep and wake cycles. In darkness the body produces more melatonin which signals to the body to prepare for sleep. In light melatonin drops and the person wakes
67
What is research support for the importance of light?
Hughes-tested circadian hormone release in 4 participants at an Antarctic Station. At end of Antarctic summer, cortisol levels followed the familiar pattern (highest point=woke and lowest point=sleep) After 3months of continuous darkness, this pattern changed peak levels of cortisol at noon rather than when waking up. Suggests extremes of daylight in polar regions may be responsible for variations in circadian hormone release. However other research in the Arctic who found similar prolonged winter darkness found no disruption in cortisol release patterns
68
What are the evaluation points for circadian rhythms?
Practical applications to shift work (leads to desynchronisation of circadian rhythms which can lead to accidents and heart disease due to stress so research has economic implications in terms of maintaining productivity and preventing accidents ), Real life applications: Chronotherapeutics (can determine best time to administer drug treatments eg risk of heart attack is greatest in early mornings so drugs can be taken at night and released in the morning, increasing efficiency ), issues with case study evidence (Siffre study was one individual, hard to generalise especially with age research ), and poor control in studies (Cave studies still had artificial lights that weren't controlled which can influence circadian rhythms so original studies lack validity )
69
When do ultradian rhythm cycles occur?
More than once a day, so its a period is less than 24 hours
70
What is an example of an ultradian rhythm?
Sleep
71
How stages of sleep are there?
Five
72
What is stage 1 sleep?
2-5% of sleep cycle. Light sleep. Muscle activity slows down. Occasional muscle twitching
73
What is stage 2 sleep?
45-55% of sleep. Breathing pattern and heart rate slows. Slight decrease in body temperature
74
What is stage 3 sleep?
4-6% of sleep cycle. Deep sleep begins. Brain begins to generate slow delta waves
75
What is stage 4 sleep?
12-15% of sleep cycle. Rhythmic breathing. Limited muscle activity. Brain produces delta waves
76
What is stage 5 sleep?
20-25% of sleep cycle. Rapid eye movement. Brain waves speed up and dreaming occurs. Muscles relax and heart rate increases. Breathing is rapid and shallow
77
What is supporting research for the sleep cycle?
Dement and Kleitman-studied 9 sleeping participants for 61 nights in a lap. They monitored the EEG record during sleep and woke participants during each of the different stages of sleep, then asked them to report their experiences and emotions
78
What did Dement and Kleitman find?
People awakened during REM sleep reported dreams 80-90% of the time in great detail and involved elaborate visual image but only 7%recall in nonREM sleep. This shows stage 5 dreaming and that delta waves make dreams less accessible. This was also shown by the fact that in deep sleep participants reported confusion and though they'd been dreaming but couldn't describe them
79
What are strengths of Dement and Kleitmans research?
The use of EEG is an objective measurement and so it is factual meaning everyone should find the same thing. Also later replications of the study have found similar things, showing the research was replicable which increases it's reliability
80
What are limitiations of Dement and Kleitmans research?
It was a lab study and so lacked mundane realism meaning sleep may have been different to if participants were at home asleep
81
What did Kleitman call the 90 minute cycle found during sleep?
The basic rest activity cycle (BRAC) and suggested however that this 90 minute ultradian rhythm continues through the day, even when we are awake, but instead of sleep stages we move to stages of alertness and physiological fatigue every 90 minutes
82
What are the different stages of the BRAC?
Awakening, morning peak, mid-morning slump, noon peak, post-lunch time slump, afternoon peak, late afternoon slump, dinner time peak, after dinner slump, intimacy peak, preparing for sleep
83
What is supporting research for BRAC?
Ericsson et al who studied practice sessions of a group of elite violinists, finding that sessions were limited to no more than 90 minutes at a time with practice systematically distributed throughout the day, and that they frequently napped to recover from practice with the best violinists napping more than teachers
84
What are the evaluation points for Ericsson?
Supported by other groups such as musicians, athletes and so it increases reliability, however these are atypical people and so this reduces validity
85
What are the evaluation points for ultradian rhythms?
Individual differences in sleep stages (Study by Tucker showed significant differences in sleep cycles between participants) and research support for the BRAC (Ericsson)
86
What are infradian rhythms?
Takes less than a day to complete, and there are weekly, monthly and annual cycles
87
What are endogenous pacemakers?
Mechanisms within the body that govern the internal, biological bodily rhytms
88
What is an exogenous zeitgeber?
An environmental cue, such as light, that helps to regulate the biological clock in an organism
89
What research did Russell et al complete?
Applied female donors underarm sweat which had been combined with alcohol to the upper lips of female participants. Found the menstrual cycle of the participants began to synchronise, suggesting that pheromones act as exogenous zeitgebers. This can conclude that menstrual cycles are governed by environmental factors
90
What is a positive evaluation point for Russel et al?
Despite the sample size being small it was a well-controlled single blind study, which is a study where only the researcher knows what group is the control group and which groups are not
91
What are annual rhythms?
In most animals, annual rhytms are related to the seasons such as migration due to lower temperatures and decreased food sources in winter. In humans there are seasonal changes in medical conditions such as depression (SAD) and chronic heart failure
92
What is seasonal affective disorder (SAD)?
A depressive disorder which has a seasonal pattern of onset and is described and diagnosed as a mental disorder by the DSM 5. It is also known as winter blues as this is when symptoms develop hence it being an infradian rhythm. It is a particular type of infradian rhythm called a circannual rhythm as it is subject to a yearly cycle
93
What do graphs displaying the correlation between SAD and day length show?
As day light decreases, depression increases
94
What are the two main endogenous pacemakers that control SAD:
The hormone melatonin and the neurotransmitter serotonin
95
What happens when melatonin and serotonin are not in a balanced equilibrium?
When an increase in melatonin occurs, leading to a fall in serotonin levels, depression can develop
96
What is a key exogenous zeitgeber in this cycle (of SAD)?
Daylight, during winter months when there is much less sunlight
97
How do stem cells act as a mechanism for functional recovery?
Number of ways. One is stem cells implanted in brain to directly replace dead/dying cells. A second way is transplanted stem cells secrete growth factors to 'rescue' injured cells. A third way is transplanted cells from a neural network, which links an uninjured brain site, where new stem cells are made, with the damaged region of the brain
98
What are the evaluation points for infradian rhythms?
Application of treatment-exposure to artificial light levels using light box helps alleviate symptoms of SAD (strength), Research studies-testing impact of infradian rhythms on hormones (strength as it's objective), biological reductionism simplistic to suggest that the disorder is purely a result of biological factors (weakness)
99
What are endogenous pacemakers for?
They are the factors inside the body that regulate biological rhythms
100
How is melatonin produced?
Within the hypothalamus there is the suprachiasmatic nucleus, which is believed to control the Pineal gland which secretes the hormone melatonin
101
What have psychologists found about melatonin?
Melatonin levels are lowest during light hours and highest during dark hours, suggesting the SCN controls the levels of melatonin to make sure we sleep during the night and stay awake during the day
102
What study was conducted by Menaker et al?
Lesioned the SCN in hamsters and found their sleep-wake cycle was disrupted. Supports view that endogenous pacemakers, at least partly, control our biological rhythms, because without it the hamsters rhythms were disrupted
103
What is the suprachiasmatic nucleus?
Tiny cluster of nerve cells in the hypothalamus that acts as 'master clock' in generating body's circadian rhythms
104
How does the suprachiasmatic nucleus link to the sleep wake cycle?
Links with other brian regions that control sleep and arousal, as well as other biological clocks throughout the body. This detects sunlight and alters out sleep-wake cycle when needed, putting the biological rhythm in time with the environment
105
How does the suprachiasmatic nucleus keep the biological rhythms in time with the environment?
It stimulates the pineal gland to produce more melatonin, which induces sleep by inhibiting the mechanisms that create wakefulness
106
How long would the brains day be without light?
25 hours long
107
Why is light an especially important zeitgeber for animals living in the dark?
Just flashes of light are enough to 'reset' the internal clocks
108
What did Aschoff 1979 study?
A blind man who needed to take stimulant and tranquillising drugs to maintain a 24 hour cycle
109
What happens if the endogenous clock is running slow?
Eg when the sun rises earlier than the day before, morning light automatically shifts clock ahead so rhythm is in step with the world outside
110
What is another endogenous pacemaker that is not the suprachiasmatic nucleus?
The pineal gland-it receives information from the SCN, when to increase production and secretion of melatonin,, and to decrease it as the light levels increase
111
Why does light cause melatonin production to stop?
So when levels of light fall, melatonin is produced, therefore inducing sleep, although the need for sleep is not affected by light, melatonin plays a role in the coordination of the sleep-wake cycle
112
What did Campbell and Murphy 98 find?
When light was shone on the back of participants' knees, many were able to shift the circadian rhythms of body temperature and melatonin secretion. Suggests that light can reach the brain without passing through the eyes
113
What does exogenous mean?
Outside the organisms
114
What does zeitgeber mean?
Time-giver
115
How is the biological clock reset every day?
By cues in the environment, such as the cues of sunrise and sunset (entrainment)
116
What is entrainment the opposite of?
Opposite of 'free running' where the biological clock works free of exogenous cues
117
What would happen if organisms were lacking in these zeitgebers?
Biological rhythms such as the sleep wake cycle would be on a different time frame to the external environment in winter as decrease in daylight or the shorter days would not be detected
118
What are some examples of zeitgebers?
Sunlight, noise and social interaction
119
Explain social cues as exogenous zeitgebers
Biologists used to think they were the main zeitgebers for human circadian rhythm. Meals eaten at socially determined times, go to bed and wake up at times designated appropriate for our age etc. Daily rhythms reset by social convention, not internal biology
120
Explain light as an exogenous zeitgeber
Dominant zeitgeber in humans after discovery that bright light suppresses melatonin production (Wever et al). Importance of light as time-giver can be difficult for blind people and messes up sleep patterns. (Miles et al studied blind mans circadian rhythms which was 24.9 hours even with exposures to exogenous zeitgebers and found it hard to reduce internal pace, suggesting light=most important zeitgeber
121
Explain temperature as an exogenous zeitgeber
Biological rhythms can be entrained by temperature eg leaves on deciduous trees change colour/fall due to change in temperature. Temperature is also a factor of hibernation, however there is no evidence to show that temperature affects human biological rhythms
122
What are the strengths for endogenous pacemakers and exogenous zeitgebers?
Animal research (Morgon et al bred mutant hamster with circadian rhythms of 20 hours then transplanted SCN into normal hamsters and rhythms swapped-supports SCN but extrapolation/generalisation and ethical issues), and implications for real life (Burgess et al-sleep wake cycle knowledge help find ways to overcome jet-lag: exposure to bright light prior to east-west flight decreased the time needed to adjust to local time on arrival by up to 2.1hours)
123
How is the nervous system divided?
It is split into the central nervous system (which is the brain and spinal cord), and the peripheral nervous system (which is the somatic nervous system and the autonomic nervous system (split into the sympathetic nervous system and the parasympathetic nervous system))
124
What is the central nervous system?
Comprised of the brain and spinal cord, and has two main functions: the control of behaviour and the regulation of the body's physiological processes
125
How does the CNS carry out it's functions?
To do it's functions, the brain must be able to receive information from the sensory receptors (eyes, ears, skin etc) and be able to send messages to the muscles and glands of the body. This involved the spinal cord, a collection of nerve cells that are attached to the brain and run the length of the spinal column
126
What is the main function of the spinal cord?
To relay information between the brain and the rest of the body. This allows the brain to monitor and regulate bodily processes, such as digestion and breathing, and to coordinate voluntary movements
127
What is the spinal cord connected to?
It's connected to different parts of the body by pairs of spinal nerves, which connect with specific muscles and glands, eg spinal nerves which branch off from the thoracic region of the spinal cord, carry messages to and from the chest and parts of the abdomen
128
What else does the spinal cord contain?
Circuits of nerve cells that enable us to perform some simple reflexes without the direct involvement of the brain eg pulling your hand away from something hot
129
What happens if the spinal cord is damaged?
Areas supplied by spinal nerves below the damaged site will be cut off from the brain and will stop functioning
130
What four main areas can the brain be divided into?
The cerebrum, cerebellum, diencephalon and brain stem
131
What is the cerebrum?
Largest part of the brain and is further divided into four lobes, each of which has a different primary function eg frontal lobe for thought and speech, the occipital lobe for processing visual images. The cerebrum is also split into two hemispheres that are responsible for different functions and communicate with each other through the corpus callosum
132
What is the cerebellum?
Sits beneath the back of the cerebrum. It is involved in controlling a person's motor skills and balance, coordinating the muscles to allow precise movements. Abnormalities of this area can result in a number of problems including speech and motor problems and epilepsy
133
What is the diencephalon?
Lies beneath the cerebrum and on top of the brain stem. Within this area are two important structures, the thalamus and hypothalamus. The thalamus acts as a relay station for nerve impulses coming from sense, routing them to the appropriate part of the brain for processing. The hypothalamus has many important functions including regulation of body temp, hunger and thirst. It also acts as a link between endocrine system and nervous system, controlling release of hormones from pituitary gland
134
What is the brain stem?
It is responsible for regulating the automatic functions that are essential for life. These include breathing, heartbeat and swallowing. Motor and sensory neurons travel through the brain stem, allowing impulses to pass between the brain and spinal cord
135
What is the peripheral nervous system?
All the nerves outside the CNS make up the peripheral nervous system. The function of this part of the nervous system is to relay nerve impulses from the CNS to the rest of the body, and from the body back to the CNS, The two main divisions are the somatic and autonomic nervous systems
136
What is the somatic nervous system?
It is made up of 12 pairs of cranial nerves (nerves directly from underside of brain) and 31 pairs of spinal nerves (from spinal cord). These nerves have sensory neurons and motor neurons. Sensory neurons relay messages to the CNS and motor neurons relay information from CNS to other areas of the body. The somatic system is also involved in reflex actions without the involvement of the CNS to allow quick reflexes
137
What is the autonomic nervous system?
It regulates involuntary actions that happen without being consciously aware of them happening eg heart beats and digestion. The ANS is necessary because vital bodily functions such as heartbeat/digestion wouldn't be as efficient if they had to be thought about. The two parts of the ANS are the sympathetic and parasympathetic nervous systems. Both regulate the same organs but have opposite effects due to the neurotransmitters associated with each division (sympathetic is generally noradrenaline which is stimulating, and parasympathetic is generally acetylcholine which is inhibitory)
138
What is the sympathetic nervous system?
It is primarily involved in responses that help us deal with emergencies (fight/flight), such as increasing heart rate and blood pressure and dilating blood vessels in muscles. Neurons from SNS travel to virtually every organ and gland, preparing body for rapid action necessary when the individual is under threat. Eg it causes the body to release stored energy, pupils to dilate and hair to stand on end, and slows bodily processes that are less important in emergences such as digestion
139
What is the parasympathetic nervous system?
It relaxes everything once the emergency passes. It slows down heartbeat and reduces blood pressure. Digestion will begin again
140
What are neurons?
Cells that are specialised to carry neural information throughout the body. Neurons can be one of three types: sensory, relay or motor. Neurons typically consist of a cell body, dendrites and an axon. Dendrites at one end of neuron receive signals from other neurons or sensory receptors. Dendrites are connected to cell body (control centre of neuron). From cell body, impulses are carried along axon where it terminates at the axon terminal. In many nerves, including in brain and spinal cord, there is an insulating layer around the axon (the myelin sheath) which allows more nerve impulses to transmit more rapidly along axon
141
What happens if the myelin sheath is damaged?
Impulses slow down
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How big are neurons?
The length can vary more a few millimetres up to one metre
143
What are sensory neurons?
Carry nerve impulses from sensory receptors to the spinal cord and the brain. Sensory receptors are found in various locations in the body eg eyes, ears, tongue and skin. Sensory neurons convert information from receptors into neural impulses. When the impulses reach the brain, they are translated into sensations eg of visual input, heat, pain etc so the organism can react appropriately. Not all sensory information travels as far as the brain as some terminate in the spinal cord (reflexes)
144
What are relay neurons?
Most neurons are not sensory or motor, but lie somewhere between the sensory input and the motor output. Relay neurons allow sensory and motor neurones to communicate with each other. These relay neurones (or interneurons) lie wholly within the brain and spinal cord
145
What are motor neurons?
The term motor neuron refers to neurones in the CNS that project their axons outside the CNS and directly or indirectly control muscles. They form synapses with muscles and control their contractions. When stimulated the motor neuron releases neurotransmitters that bind to receptors on the muscle and triggers a response which leads to muscle movement. When the axon of a motor neuron fires, the muscle with the synapses contracts. The strength of the muscle contraction depends on the rate of firing of the axons of motor neurons that control it. Muscle relaxation is caused by inhibition of motor neurons
146
What is synaptic transmission?
It is the process by which a nerve impulse passes across the synaptic cleft from one neuron (presynaptic neuron) to another (postsynaptic neuron)
147
What is the process of synaptic transmission?
Action potential arrives at terminal button, action potential reaches synaptic vesicles, neurotransmitter is released, neurotransmitter is released across synaptic gap, neurotransmitter binds to specialist receptors, receptor cell is activated, receptor molecules produce effect (excitatory or inhibitory), post synaptic neuron re-uptakes leftover neurotransmitter for later release
148
How long does the process of synaptic transmission take?
Only a fraction of a second, with the effects terminated at most synapses by re-uptake. The quicker it is taken back, the shorter the effects on the postsynaptic neuron. Some antidepressants prolong the action of the neurotransmitter by inhibiting the re-uptake process so the neurotransmitter is in the synapse for longer. Neurotransmitters can also be turned off after they have stimulated the postsynaptic neuron which takes place through the action of enzymes produced, making the neurotransmitter ineffective
149
What are neurotransmitters?
Chemical messengers that carry signals across the synaptic gap to the receptor site on the postsynaptic cell. Neurotransmitters can be classified as excitatory or inhibitory in their action
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What are excitatory neurotransmitters?
Eg acetylcholine and noradrenaline, are the nervous systems 'on switches'. They increase the likelihood that an excitatory signal is sent to the postsynaptic cell, which is then more likely to fire
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What are inhibitory neurotransmitters?
Eg serotonin and GABA, are the nervous systems 'off switches'. in that they decrease the likelihood of that neuron firing. They are generally responsible for calming the mind and body, inducing sleep, and filtering out unnecessary excitatory signals
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What happens when an excitatory neurotransmitter binds with a postsynaptic receptor?
It causes an electrical change in the membrane of that cell, resulting in an excitatory post-synaptic potential (EPSP) meaning that the postsynaptic cell is more likely to fire
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What happens when an inhibitory neurotransmitter binds with a postsynaptic receptor?
It results in an inhibitory postsynaptic potential (IPSP), making it less likely that the cell will fire
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What happens when a nerve cell receives both EPSPs and IPSPs?
The likelihood of the cell firing is therefore determined by adding up the excitatory and the inhibitory synaptic input. The net result of this calculation (summation) determines whether or not the cell fires
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How can the strength of an EPSP be increased?
In two ways. In spatial summation, a large number of SPSPs are generated at many different synapses on the same postsynaptic neurone at the same time. In temporal summation, a large number of EPSPs are generated at the same synapse by a series of high frequency action potentials on the presynaptic neurone
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What is the rate at which a particular cell fires at determined by?
The rate at which a particular cell fires is determined by what goes on in the synapses. If the excitatory synapses are more active, the cell fires at a high rate. If inhibitory synapses are more active, the cell fires at a much lower rate, if at all
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What is the endocrine system?
A network of glands throughout the body that manufacture manufacture and secrete chemical messengers (hormones)
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What are endocrine glands?
They produce and secrete hormones, chemical substances that regulate the activity of cells or organs in the body
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What are the major glands of the endocrine system?
They include the pituitary gland, adrenal glands and the reproductive organs. They each produce different hormones which regulate the activity of organs and tissues in the body
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How is the endocrine system regulated?
By feedback similar to how a thermostat regulates temperature in a room. Eg a signal is sent from hypothalamus to pituitary gland un the form of a 'releasing hormone', causing the pituitary to secrete a 'stimulating hormone' into bloodstream, which then signals the target gland eg adrenal glands to secrete the hormone. As the levels of the hormone rises in the bloodstream, the hypothalamus shuts down secretion of the releasing hormone and pituitary glands stop secreting of stimulating hormone. This slows secretion of target gland's hormone resulting in stable concentration of hormones circulating the bloodstream
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What are hormones?
Chemicals that circulate in the bloodstream and are carried to target sites throughout the body. The word hormone comes from Greek word hormao meaning 'I excite' which refers to the fact that each hormone 'excites' or stimulates a particular part of the body
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How do hormones work?
They come into contact with most cells in the body, but a given hormone usually affects only a limited number of cells (target cells) which respond to a particular hormone as they have he receptors for it. If a cell doesn't have such a receptor, then they cannot be directly affected by that hormone. When enough receptor sites are stimulated, there will be a physiological reaction in the target cell
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Why is timing an important part of hormone release?
Timing is critical because too much or too little at the wrong time can result in dysfunctional bodily systems. Eg too high a level of cortisol can lead to Cushing's syndrome characterised by high blood pressure and depression-the most common cause of excess cortisol is a tumour in the pituitary gland which makes too much adrenocorticotrophic hormone (ACTH) which makes the adrenal glands produce too much cortisol
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What is the pituitary gland?
It produces hormones whose primary function is to influence the release of hormones from other glands, and in so doing regulate many of the body's functions. As the 'master gland' it produces hormones that travel in the bloodstream to their specific target, which either directly causes changes in physiological processes in the body or stimulates other glands to produce hormones
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What is the pituitary gland controlled by?
The hypothalamus, a region of the brain just above the pituitary gland. It receives information from many sources about the basic functions of the body, then uses the information to help regulate these functions. One of the ways it does this involves controlling the pituitary gland
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What is negative feedback?
High levels of hormones produced in other endocrine glands can stop the hypothalamus and pituitary releasing more of their own hormones, which is negative feedback, and prevents hormone levels from rising too high
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What are the two main parts to the pituitary gland?
The anterior (front) pituitary and the posterior (back) pituitary. These two parts release different hormones, which target different parts of the body
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What does the anterior pituitary release?
An example is ACTH as a response to stress. ACTH stimulates the adrenal glands to produce cortisol. The anterior pituitary also produces two hormones important in the control of reproductive functioning (LH and FSH)
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What does the posterior pituitary release?
An example is oxytocin, which simulates contraction of the uterus during childbirth, and is important for mother-infant bonding. Recent research using mice has found that oxytocin is necessary for healthy maintenance and repair, and it declines with age
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What are the adrenal glands?
There are two, and they sit on top of the kidneys. The name 'adrenal' relates to their location (ad-near renes-kidneys). Each one is made of two parts. The outer part is the adrenal cortex and the inner region is the adrenal medulla. They both have very different functions. One difference is the hormones released by the adrenal cortex are necessary for life but those produced by the adrenal medulla are not
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What hormones are produced by the adrenal cortex?
It produces cortisol which regulates/supports a variety of important bodily functions such as cardiovascular and anti-inflammatory functions. It is also increased in response to stress (if it is low then there will be high blood pressure, poor immune function and inability to deal with stress). It also produces aldosterone which is responsible for maintaining blood volume and pressure
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What hormones are produced by the adrenal medulla?
It releases adrenaline and noradrenaline, hormones that prepare the body for fight or flight. Adrenaline helps the body respond to stressful situations eg my increasing heart rate and blood flow to muscles/brain. Noradrenaline constricts blood vessels to increase blood pressure
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What is the fight-or-flight response?
A sequence of activity within the body that is triggered when the body prepares itself for defending or attacking (fight) or running away to safety (flight). This activity involves changes in the nervous system and the secretion of hormones that are necessary to sustain arousal
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When an individual is faced with a threat, what part of the brain becomes involved?
The amygdala is mobilised, which associates sensory signals such as what we hear/see, with emotions associated with fight or flight such as fear/anger. The amygdala then sends a distress signal to the hypothalamus which functions like a command centre in the brain, communicating with the rest of the body throughout the sympathetic nervous system. The body's response to stressors involve two major systems-one for acute stressors and one for chronic stressors
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What is involved in response to acute (sudden) stressors?
The sympathetic nervous system, adrenaline and the parasympathetic nervous system
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How is the sympathetic nervous system involved with responding to acute stressors?
When the sympathetic nervous system is triggered, it begins the process of preparing the body for the rapid action necessary for fight or flight The sympathetic nervous system sends a signal throughout the adrenal medulla, which responds by releasing the hormone adrenaline into the bloodstream
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How is adrenaline involved with responding to acute stressors?
As it circulates through the body, it causes a number of physiological changes. The heart beats faster, pushing blood to muscles, heart and other vital organs, and blood pressure increases. Breathing becomes more rapid in order to take in as much oxygen as possible with each breath. Adrenaline also triggers release of glucose and fats which flood into bloodstream to supply energy to parts of the body associated with fight/flight response
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How is the parasympathetic nervous system involved with responding to acute stressors?
When the threat has passed, the parasympathetic branch of the autonomic nervous system dampens down the stress response. It slows the heartbeat again and reduces blood pressure, it also begins the process of digestion again
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What are chronic stressors?
If the brain continues to perceive something as threatening, the second system begins. As the initial surge of adrenaline subsides, the hypothalamus activates a stress response system called the HPA axis, consisting of the hypothalamus, pituitary gland and adrenal glands
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What is the 'H' part of the HPA axis?
The hypothalamus. The HPA axis relies on a series of hormonal signals to keep the sympathetic nervous system working. In response to continued threat, the hypothalamus releases a chemical messenger, corticotrophin-releasing hormone (CRH) which is released into bloodstream into response to the stressor
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What is the 'P' part of the HPA axis?
The pituitary gland. On arrival at the pituitary gland, the CRH causes the pituitary to produce and release adrenocorticotrophic hormone (ACTH). From the pituitary, ACTH is transported in the bloodstream to its target site in the bloodstream to its target site in the adrenal glands
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What is the 'A' part of the HPA axis?
ACTH stimulates adrenal cortex to release various stress-related hormones, including cortisol, which is responsible for several effects in the body that are important in fight-or-flight response. Some are positive eg quick burst of energy, and others are negative eg lowered immune response
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How is the HPA axis regulated?
It is very efficient at regulating itself. Both the hypothalamus and pituitary gland have special receptors that monitor circulating cortisol levels. If these rise above normal, they initiate a reduction in CRH and ACTH levels, thus bringing cortisol levels back to normal
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What are the evaluation points for fight or flight?
The 'tend and befriend' response, negative consequences of the fight or flight response, 'fight or flight' does not tel the whole story, positive rather than 'fight or flight' behaviours, and a genetic basis to sex differences in the fight or flight response
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How is the 'tend and befriend' response an evaluation point for the fight or flight response?
Taylor et al suggest that, for females, behavioural responses to stress are more characterised by a pattern of ten and befriend than fight or flight, involving protecting themselves and young through nurturing behaviours and forming protective alliances with other women. Women may have a completely different system for coping with stress due to evolution in the context of being the primary caregiver of children so they aren't left at risk
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How are negative consequences of the fight or flight response an evaluation point for the fight or flight response?
The physiological response may be adaptive for a stress response that requires energetic behavioural responses. However, the stressors of modern life rarely require such levels of physical activity. The problem for modern humans arises when the stress response is repeatedly activated eg increased blood pressure can lead to physical damage in blood vessels leading to heart disease. Also although cortisol assists in fighting viral infections/healing damaged tissue, too much of it suppresses the immune response as a whole
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How is 'the fight or flight does not tell the whole story' an evaluation point for the fight or flight response?
Gray argues the first phase of reaction to a threat isn't fight or flight, it is to avoid confrontation. He suggests that prior to responding with attacking or fleeing, most animals (+humans) display a freeze response. The initial freeze is essentially 'stop, look and listen' where the animal is hyper-vigilant. The adaptive advantages are that is focuses attention in order to make the best response decision to a particular threat
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How is 'positive rather than fight or flight behaviours' an evaluation point for the fight or flight response?
Von Dawans et al challenge the classic view that under stress, men only respond with fight or flight and women are more prone to tend and befriend. The study found that acute stress can actually lead to greater cooperative/friendly behaviours, even in men. This could explain human connection that happens in times of crisis such as 9/11 in New York. This may be because humans are fundamentally social with a protective nature, allowing the species to thrive
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How is 'a genetic basis to sex differences in the fight or flight response' an evaluation point for the fight or flight response?
Lee and Harley found evidence of a genetic basis for gender differences in fight or flight response. The SRY gene found only in the male Y chromosome, directs male development, promoting aggression and the fight or flight response. They suggest this gene may prime males to respond to stress in this way by releasing stress hormones such as adrenaline and increased blood flow to organs involved in fight or flight. The absence of this gene in females + the action of oestrogen and oxytocin may prevent this response to stress
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What are the ways of studying the brain?
Post-mortem examinations, functional magnetic resonance imaging, electroencephalogram, and event-related potentials
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What are post mortem examinations used for?
To establish the underlying neurobiology of a particular behaviour. When a person dies, abnormalities in the brain can be found to explain a behaviour
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What are examples of how post-mortem examinations have been used in psychology?
It has found links between psychiatric disorders and underlying brain abnormalities, eg Cotter et al who found a link between depression and reduced numbers of glial cells in the frontal cortex
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What are the strengths of post-mortem examinations?
Allow for more detailed exam of anatomical and neurochemical aspects of the brain, not possible with non-invasive scanning techniques, eg it can reach the hypothalamus and hippocampus. Another strength is that it has played a central part in understanding the origins of schizophrenia (claimed by Harrison)
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What are the limitations of post-mortem examinations?
People die in a variety of circumstances and at varying stages of disease, so these factors can influence the post-mortem brain. So can time between death and the exam, drug treatments and age at death (confounding influences). Also it is limited as it is retrospective-the person already died so the researcher cannot follow up on anything that arises from the exam concerning possible relationships between brain abnormalities and cognitive functioning
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What is functional magnetic resonance imaging?
It measures changes in brain activity while doing a task, by looking at changes in blood flow in areas of the brain to show where there is increased neural activity. More active areas need more oxygen so more blood is needed, therefore a map of brain activity for particular mental tasks can be produced
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What is an example of how fMRIs can be used in psychology?
Participants alternate between a task and control state, eg 30 seconds of visual stimuli then 30 seconds with eyes closed, so a map can be produced to show what brain areas where involved with the visual stimuli
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What are the strengths of fMRIs?
They are noninvasive and do not produce any harmful radiation like with other scanning techniques. Also they are more objective and reliable than verbal reports so they can also study things that aren't possible with verbal reports
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What are the limitations of fMRIs?
They measure blood flow changes so it isn't a direct measure of neural activity, and isn't truly quantitative. Also it overlooks the networked nature of brain activity by only focusing on localised activity in the brain when it is communication among different regions that is the most critical mental function
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What is an electroencephalogram?
It measures electrical activity in the brain by electrodes on the scalp that detect small electrical charges from activity of brain cells. It can be used to detect brain disorders (epilepsy/alzheimers etc). The four basic EEG patterns are alpha (awake/relaxed), beta (REM sleep), delta and theta (both sleep)
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What are the strengths of EEGs?
Brain activity is recorded in real time rather than still images so it can be seen during different tasks so the effect of that task can be accurately measured. Also it is really useful in clinical diagnosis, eg for diagnosing epilepsy
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What are the limitations of EEGs?
They can't reveal what happens in deeper regions of the brain as that would be too invasive to use this technique to look at areas such as the hypothalamus that are deeper in the brain. Also it is hard to pinpoint the exact source of activity as neighbouring electrodes can also detect activity, so it can be hard to distinguish between activities originating in different but closely adjacent locations in the brain
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What are event related potentials?
Very small voltage changes in the brain triggered by specific events or stimuli, such as cognitive processing of a specific stimulus [add to later]
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What are the strengths of event related potentials?
Continuous measure so can look at how processing is affected by specific experimental manipulation. It can also measure this in the absence of a behavioural response
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What are the limitations of event related potentials?
Small/difficult to pick out so need large numbers of trials. Also only strong voltage changes are recorded so important electrical activities deeper in the brain aren't recorded. It can only measure the neocortex
