Neuroscience and Behaviour Flashcards
1
Q
What do neurons consist of?
A
- Dendrite - tree
- Cell body - soma
- Axon - myelin
2
Q
Diagram of neuron
A
3
Q
What are gilal cells?
A
Support cells
Cells that support the functionality of neurons by providing physical support, supplying nutrients and enhancing neuronal communication
Very important in brain function
4
Q
Where are gilal cells found?
A
central nervous system (brain and spinal cord)
5
Q
What does synpase do?
A
electrical signal (the action potential) into a chemical signal in the form of neurotransmitter release, and then, upon binding of the transmitter to the postsynaptic receptor, switching the signal back again into an electrical form
6
Q
What are the three major neuron types?
A
–sensory
–motor
–interneurons/relay
7
Q
What are neurons?
A
Cells in the nervous system that communicate with one another to perform information-processing tasks
8
Q
What is cell body other name as?
A
Soma
9
Q
What is cell body?
A
Largest component of the neuron
Coordinates the information-processing taska dn keeps the cell alive
Functions such as protein synthesis, energy production and metabolism take place here
Contains nucleus which has chromosomes contains DNA/genetic bllueprint
10
Q
What is the cell body surrounded by?
A
Porous cell membrane that allows molecules to flow into and out of the cell
11
Q
What are the two types of specialised extensions of the cell membraneto allow communication?
A
Axons and dendirtes
12
Q
What are the dendrites?
A
Recieve information from other neurons and relay it to the cell body
Many dendrites that look like tree brances
13
Q
What are axons?
A
Transmit information to other neurons, muscles or glands
Each neuron has a single axon that sometimes can be very long
14
Q
What are axons covered by?
A
Myelin sheath
15
Q
What are myelin sheath?
A
Insulating layer of fatty material made up of glial cells
16
Q
Advantages of myelin seath
A
When axons insulated with myelin it can more efficiently transmit signals to other neurons, organs or muscles
17
Q
What happens in demyelinating disease e,g multiple sclerosis
A
Myelin sheath deterioates causing a slowdown in the transmission of information from one neuron to another
Variety of problems such as loss of feeling in limbs, partial blindess and difficulties in corrdination
18
Q
What is synapse?
A
Junction or region between the axon of one neuron and the dendrites or cell body of another
19
Q
Who discovered the neurons?
A
Cajal
20
Q
What are sensory neurons?
A
Receive information from the external world and convey this information to the brain via the spinal cord
21
Q
How are sensory neurons specialised?
A
Specialised endingson their dendrites that recieve signals fro light, sound ,touch , taste and smell
e.g sensory neurons’ endings are sensitive to light
22
Q
What do motor neurons carry?
A
Signals from the spinal cord to the muscles to produce movement
23
Q
How are motor neurones specialised?
A
Long axons that can stretch to muscles at our extremeities
24
Q
What are interneurons?
A
Connect sensory neurons, motor neurons or other interneurons
Carry information from sensory neurons into the nervous system , others carry info from nervous system o the motor neurons
Perform variety of information-rpocessing functions within the nervous system
Work together to perform simple tasks e.g identifying location of sensory signal, recognising a familiar face
25
What are Purkinje cells?
Interneuron that carries information from the cerebellum to the rest of the brain and spinal cord
Dense,elaborate dendrites that resemble bushes
26
What are pyramidal cells?
Found in the cerebral cortex
Triangular cell body and single long dendrite among many smaller dendrites
27
What are biploar cells?
Type of sensory neuron found in the retinas of the eye
Have a single axon and few dendrites
28
Diagram of purkinje cell , hippocampal pyramidal and biploar cell
29
Our thoughts, feelings and action depend on neural communication but how does it happen?
Communication of information within and between neurones go in two stage
conduction and trasmission
conduction - conduction of electrical signal over relatively long distances within neurons from dendrites to cell body throughout axon
Transmission - electrical signal between neurons over the synapse
these are electrochemical action of neurones
30
Neurons have an natura electrical change called what?
Resting potential
31
What does resting potential mean?
Difference in electric charge between the inside and outside of neuron's cell membrane
## Footnote
–natural electric charge
–concentration of ions inside and outside cell
32
How does the resting potential arise?
From difference in concentrations of ions inside and outside the neuron's cell membrane
Ions carry + or -charge
33
Resting potential
sodium and potassium ion gradient
How this test shows differences in K+ concern is basis of resting potential
* Resting state: High con of K+ inside neuron compared to low K+ outside neuron
* Raising K+ in fluid outside neuron to match conc of K+ inside causing resting potential to disappear
*
34
Resting potential
sodium and potassium ion gradient
The concentration of K+ inside and outside an axon controlled by axon membrane that allow molecules to flow in and out of the neuron
Resting potential Chanells allow K+ molecules inside the neuron so K+ molecules move out neurons through the open channels leaving the inside of the neuron with charge of -70 millivolts to outside
35
Conduction of large electrical impulse down the length of axon
What is this called?
Action potential
36
What is an action potential?
Electrical signal that is conducted along the length of a neuron's axon to the synapse
37
When does action potential occur?
Only when electric shock reaches a certain level or threshold
Change in state of axon's membrane
38
What happens when an electric shock is below this threshold?
Researchers recorded only tiny signals which dissipated rapidly
39
What happens when the shock reaches the threshold?
A much larger signal the action potentia, onbserved
Did not increase the strength of action potential
occurs same magnitude regardless of whether stimulus is at or above threshold
40
What is the myelin sheath?
Made up of glial cells
41
The axons end in what?
Terminal buttons
42
What are terminal buttons?
Knoblike structures that branch out from an axon
43
What are the terminal buttons filled with?
Tiny vesicles that contain neurotransmitter
Neurotransmitter - transmit information across the synapse to a receiving neuron dendrites
44
What do dendrites of the recieving neuron contain?
Receptors - part of the cell membrane that receive neurotransmitters and initiate new electric siignal
45
46
How would dendrites know which of the neurotransmitters flooding to the synpase to reiceve and which to ignore?
1. Neurons tend to form pathways in the brain that are characterised by specific types of neurotransmitters; one neurotransmitter might be prevalent in one part of the brain and other may be prevalent in a different oart
2. Neurotransmitter and receptor act like lock and key model. bind to receptor specificlly.
47
What happens to the leftover neurotransmitter left in the synpase after chemical message is relayed to postsynaptic neuron?
Three processes where neurotransmitter leave the synapse
* Reputake occurs when neurotransmitters are reabsorbed by the terminal buttons of the presynaptic neuron axon
* Neurotransmitters can be destroyed by enzymes in synapse in process called enztme deactiviation where specific enzymes bind to receptor sites called autoreceptor on presynaptic neurons
* Autoreceptors detect how much of a neurotransmitter has been released into a synpase and signal the neuron to stop releasing the neurotransmitter when excess is in process
48
What is acetlycholine (ACh)
Neurotransmitter involved in a number of functions including voluntary motor colour
49
Diagram of neurotransmitter and functions
50
How can drugs affect the nervous sytem?
Increasing , interfering with or mimicking the manufacture or function of nuerotransmitters
51
What are agonists?
Drugs that increase the action of a neurotransmitter
52
What is anatagonists?
Drugs that block the function of a neurotransmitter
53
Agonists vs Antagonists?
Drugs alter a step in production or release neurotransmitter
Whereas others have a chemical structure so similar to a neurotransmitter that the drug is able to bind to neuron receptor
If bind to receptor, drug activates neurotransmitter agonist
If blocks the action of the neurotransmitter it is antagonist
54
Diagram of agonist vs antagonist
55
More information on L-dopa
* Developed to treat Parkinsons movement disorder characteristced by terms and difficulty to initiate momvent caused by loss of neurons that use the neurotransmitter dopamine
* Dopmaine is created by amount of L-dopa in the brain and spur the surviving neurons to produce more dopamine
* L-dopa is an agonist for dopamine
* Effectiveness of L-dopa decreases when used over a long period of time
56
Evidence for central role of dopamine to regulate movement and motor performance
1982 study
* 6 people ranging from age (25-45) from San Franciso Vay admitted to emergency rooms with symptoms: paralysis, drooling and inability to speak
* Diagnoise of Parkinson was made
* Unusal for 6 people to have Parkinson this young with advanced at the time at same area
* None had Parkinson but were heroin addicts
* They thought they were ingesting a synthetic form of heroin MPPP but instead ingested derivative called MPTP effect of destroying dopamine producing neurons in brain crucial for motor performance
* Recovery recieeving L-dopa acts agonist by enhancing properties of dopamine
* Drugs like MPTP act as antagonists destryoing dopamine producing neurons
57
How can Amphetamine alter neurotransmitter function
Stimulates release of noradrenaline and dopamine
Both amphetamine and cocaine prevent the reuptake of noradrenaline and dopamine
Combination of increased release of noradrenaline and dopamine and prevention of their uptake flood synapse with neurotransmitter resulting increased activation of their receptor
Both drug strong agonist
Noradrenanline and dopamine play role in mood control either neurotransmitter result in euphoria, wakefulness and burst of energy
However, noradrenaline increase heart rate
Overdore of amphetamine or cocaine cause heart to contract so rapidly that heartbeats di not last long to pump blood effectively leading to fainting and sometimes to death
58
How does Prozac work?
Drug used to treat depression e.g agonist
Blocks the reuptake of neurotransmitter serotonin (drug is elective sertonin reuptake inhibiter SSRIS)
Depression have reduced levels of serotonin in brain
Blocking reuptake more of the neurotransmitter reminas in synapse longer and produces great activation of sertonin receptor
Help elevate mood relieve depression
59
What is beta blockers
Antagonist?
Obstruct a receptor site for noradrenaline in heart
Noradenline cannot bind to receptor heart rate slows down which is helpful for disorders which heart beats too fast or irreguarly
Prescribed to reduce agitation , racing heart and nervousness associated with stage fright
60
What is nervous sytem?
Interacting network of neurons that conveys electrochemical information throughout the body
61
What are the two major divsions of the nervous system?
1. Central Nervous System CNS
2. Peripheral Nervous System PNS
62
What is CNS?
Composed of brain and spinal record
Recieve sensory information from the external world, processes and coordinates this information and sends commands to the skeletal and muscular system for action
Rests the brain which contain sutrctures that support complex perceptual, motor, emotional and cognitive functions of the nervous sytem
Spinal cord branches down from the brain; nerves process sensory information and relay commands to the body connect to the spinal cord
63
What is PNS?
Connects the central nervous system to the body's organ and muscle
Composed of two major subdivisions
64
What are subdivsions of PNS?
* Somatic nervous system
* Autonomic nervous system
65
What is somatic nervous system?
Set of nerves that convey information in and out of CNS
Humans have conscious control over this system and use it to perceive, think and coordinate behaviours
e.g pick up coffee cup involves elegantly orchestrated activities of somatic nervous system
info from receptor in eye travels to brain registering cup from table
signals from your brain travel to arm and hand
Feedback from muscles tells your brain that cup has been grasped
66
What is ANS Autonomic nervous system?
Set of nerves that carry involuntary and automatic commands that control blood vessels, body rogans and glands
System works on its own to regulate bodily system and largely outside conscious control
67
What is ANS two major subdivisions?
1. Sympathetic nervous system
2. Parasympathetic nervous system
68
What is sympathetic nervous system?
Set of nerves that prepare the body for action in threatening situations
Nerves emanate from top and bottom of spinal cord and connect to variety fo organs such as eyes, salivary glands, heart and lungs, digestive organs and sex organis
Coordinate control of these organs so body can take action by fleeing the threating situation/ prepare fight of flight
69
Sympathetic nervous sytem
e.g fight or flight
* Hear footsetps behind you in a dark ally
* Feel frightened and turn to see someone approaching you from behind
* Dilates pupils to let in more light, increases your heart rate and respiration to pump more oxygen to muscles
* Diverts blood flow to brain and muscle to activate sweat glands and to cool body
* Converse energy Sympathetic nervous system inhibit salivation and bowel movement and immune responses and suppresses to pain and injury
* Likelhood to deal threat on ground or making escape
70
What does parasympathetic nervous system help?
Body to return to nomral resting state
e.g Far away from attacker body doesn't need to remain on red alert and kick in reverse effects of the sympathetic nervous system and return the body to a normal state
Mirror connection of the sympathetic nervous system
e.g parasympathetic constricts your pupils and slows down heart rate and respiration
diverts blood flow to your digestive system and decreases activity in your sweat gland
71
How do synpathetic and parasympathetic nervous system coordinate to control many bodily functions
e.g Sexual behaviour
* In men the parasympathetic nervous system enorges the blood vessels of the penis to produce an erection
* However, sympathetic nervous system is responsible for ejacuation
* In women: parasympathetic nervous system produces vafinal lubritication but sympathetic nervous system underlies orgasm
72
How do synpathetic and parasympathetic nervous system coordinate to control many bodily functions
e.g Sexual behaviour
Men and women successful suxal experience depends on balance of two systems
anxiety about sexual performance disrupt this balance
e.g
* Sympathetic nervous system activation caused by anxiety can lead to premature ejaculation in males and lack of lubrication in females
73
Connections between sensory inputs and motor neurons in the spinal ord mediate what?
Spina reflexes
74
What are spinal reflexes?
* Simple pathways in the nervous system that rapidly generate muscle contractions
75
Example of using spinal reflexes
If you touch a candle flame, the sensory neurons that register pain and send inputs directly into the spinal cord
Through a few synaptic connections within the spinal cord, interneurons relay these sensory inputs to motor neurons that connect to your arm muscles and direct you to quickly retract your hand
76
What could happen to elaborate tasks?
Collabration of spinal cord and the brain
Peripheral nervous system communicates with CNS through nerves that conduct sensory info into the brain carry commands out of the brain or both
Brain sends commands for voluntary movement through the spinal cord to motor neurons whose axons project out to skeletal muscles and send message to contract
77
What happens if spinal cord is damaged?
Severs the connection from the brain to the sensory and motor neurons that are essential to sensory perception and movement
78
Location of spinal injury often determine the
extent of abilities are lost
different regions of spinal cord control different systems of the body
79
What happens with paitents with damage at particular level of spinal cord?
Lose sensation of touch and pain in body parts below of the level of injury as well as loss of motor control of muscles in same area
80
What happens if higher area of spinal cord is damaged?
Usually predicts a more poorer pognosis such as quadriplegia (loss of sensation and motor control over all limbs)
breathing through a respirator and lifelong immobility
81
Where is the hindbrain?
Follow spinal cord from your tailbone to where it enters your skull you will find it difficult to determine where your spinal cord ends and brain begins
because spinal cord is continuous with hindbrain
82
Definition of hindbrain
Area of the brain that coordinates information coming in and out of the spinal cord
83
What is the hindbrain sometimes known as?
Vrain stem
84
What does the hindbrain control?
Most of the basic functions of life:
respiration
altertness
motor skills
85
What does the three antaomical structures include in hindbrain?
1. Medulla
2. Cerebullum
3. Pons
86
What is the medulla?
Extension of the spinal cord into the skull that coordinates heart rate, circulation and respiration
87
What does the medulla inside?
Small cluster of neurons called reticular formation
88
What is reticular formation?
Brain structure that regulates sleep, wakefulness and levels of arousal
89
What happens if the reticular formation is damaged?
Large consequences of behaviour
E.g Researchers stimulated recticular formation of sleeping cat
Caused animal to awaken almost instantouesly and remain alert
However, serving connections between this and rest of brain caused animal to relapse into a coma
90
Where is the cerebullum located?
Behind the medulla
91
What is the cerebullum?
Large structure of the hindbrain that controls fine motor skills
Orcherstates proper sequence of movement when e.g riding bike, playing piano
92
What does the cerebullum contain?
Layer of Purkinje cells
Largest neurons in the brain and sole output for motor coordination and orginating the cerebellum and spreading it to the rest of the brain
93
What happens if the cerebellum is damaged?
* Produces impairment in coordination and balance
* NOT paralysis or immobility
* Role in crebullum as contributes to fine tuning of behaviour rather than initiation of bheaviour
94
What is pons?
Structure that relays information from the crebullum to the rest of the brain
Acts as relay station or bridge between the cerebellum and other structures in the brain
95
Where is midbrain?
Sitting ontop of the hindbrain
96
What two structures do the midbrain contain?
Tectum and tegmentum
97
What is the tectum?
Orients an organisim in envirnoment
Recieve stimulus input from eyes, ears and skin and moves organism in a coordinated way to stimulus
e.g when studying in quiet room and hear click behind and to the right of you, body swivel and orient to the direction of the sound
98
What is tegmentum ?
Involved in movement and arousal and helps organism orient towards sensory stimuli
abundance of dopamine producing neurons found in midbrain structure
dopamine contributes to motor , behaviour, motivation and pleasure
seretonin also contributes to mood
99
How to survive with only hindbrain and midbrain?
Structures in hindbrain would take care of all the boduily functions necessary to sustain life
Structures in midbrain would oreint you towards or away from pleasuring or threatening stimuli
100
What is the forebrain?
Highest level of the brain
Controls complex cognitive, emotional, sensory and motor functions
Forebrain divided into main sections :crebral cortex and subcortical structures
101
What is cerebral cortex?
Outermost layer of the brain visibile to the naked eye and divided into two hemispheres
102
What is subcortical structures?
Areas of the forebrain housed under the cerebral cortex near the very centre of the brain
103
What is the thalamus?
Relays and fitlers information from the senses and transmits the information to the cerebral cortex
Recieves inputs from all the major senses expect smell which has direct connections to the cerebral cortex
Closes pathway of incoming sensations during sleep, providing valuable function is not allowing information to pass to rest of the brain
104
What is hypothalamus?
Below thalamus
Regulates body temperature, hunger, thrist and sexual behaviour
Overseas wide range of behaviours
e.g make sure body temp, blood sugar levels and metabolism kept within an optimal range
105
What happens if there is lesions in hypothalamus?
Result in overeating whereas ther areas leave animal no desire for food at all
106
e.g sex
hypotalhalamus role
Messages from cerebral cortex are sent to hypothalamus to release hormones
107
Electrical stimulation in cats prduce
e.g hissing and biting
when hypothalamus can also produce intense pleasure for an animal
108
What did James Olds and Peter Milner found?
Small electric current delivered to certain region of rat's hypothalamus was extremely rewarding for the animal
When allowed to press bar attached to electrode to initiate their own stimulation
Rats do it repeatedly to point of exhausation
Therefore, hypothalamus in charge of behaviour: fighting, fleeing, feeding and mating
109
Where is pituarity gland located?
* Below hypothalamus
110
Definition of pituarity gland
Master gland of the body's hormone producing system
Releases hormones that direct functions of many other glands in the body
Hyothalamus sends hormone signals to pituarity gland and sends hormonal signals to other glandsto control stress, digestive activities and reporductive process
e.g when baby suckles on its mother;s breast sensory neurons in breast send signals to her hypothalamus then piturarity gland to release hormone oxytocin into blood stream to release milk
111
How is pituaritty gland related to stress?
* When we sense a threat
* Sensory neurons send a singal to the hypothalamus which stimulates release of ACTH hormone from the pitruarity gland
* ATCH stimulates adrenal glands (above kidneys) to release hormones that activate sympathetic nervous system
112
The hypothalamus is part of limbic system what doesn't that mean?
Group of forebrain structures which also include the amygdala and the hippocampus which are involved in motivation, emotion, learning and memory
113
What does the limbic system form?
Boundary where subcortical structures meet the cerebral cortex
Two remaining structure of limbic system are hippocampus and amygdala
114
What is the hippocampus?
Critical for creating new memories and integrating them into a network of knowledge so that can be stored indefinitely in other parts of cerebral cortex
115
What if people damage their hippomcapus?
Acquire new information and keep it in awareness for few seconds but forgot
116
What is amygdala?
Located at the tip of each horn of hippocampus
plays central role in many emotional process particular the formation of emotional memories
Attaches to significance to previously neural events that are associated with fear, punishment and reward
117
Example of amygdala
A car came speeding towards you as you cross the road
Stimuli car - don't have a panic attack each time
Emotional connection to events e.g fearful
118
What is basal ganglia?
Set of subcortial structurs that direct intentional movements
located near the thalamus and hypothalamus and they receive inputs from the cerebral cortex and send outputs to the motor centres in the brain stem
119
One part of the basal ganglia is the striaum involved in what?
Control of posture and movement
120
Paitents suffering from Parkinsons
Show symptoms of uncontrollable shaking and sudden jerks of the limbs and unable to initiate a sequence of movements to achieve a specific goal
Happens because dopamine-producing neurons in the substantial nigra are damaged
Undersupply of dopamine then affects the striatum turns to visible behavioural symptoms
121
Is the cortex highest level of brain?
Yes
Responsible for complex aspects of perception, emotion, movement and thought
122
What is the smooth surface of the cortex called?
Gyri
123
Identation or fissures of brain are called?
Sulci
124
Cerebral cortex can be understoof by three levels?
Separation of the cortex
Two hemispheres
Function of each hemisphere
Role of specific cortical areas
125
First level of organisation in cerebral cortex
Dvided cortex into left and right hemispheres
They are symmetrical
Each hemisphere controls the function of the opposite side
126
What does contralateral control mean?
Right cerebral hemisphere percieves stimuli from and controls movement on the left side of your body
Whereas left cerebral hemisphere perceives stimuli and controls movement on the right side of body
127
What are cerebral hemispheres connected by?
Commisures
Bundle of axons that mkae connuncation between parallel areas of the cortex in each half
Half o the commissions is corpus callosum
Info received in right hemisphere e.g pass along corpus callosum and registered virtually instanteously in left hemisphere
128
What is corpus callosum?
A thick band of nerve fibres that connect large areas of the cerbral cortex on each side of the brain and supports communication of information across the hemispheres
129
The second level of organisation
Cerebral cortex distinguishes the functions of different regions within each hemisphere
Each hemisphere is divided into four areas or lobes from front to back
130
Where is occitpal lobelocated at?
Back of the cerebral cortex
Processes visual information
Sensory receptor in eyes send info to thalamus which turns info to primary areas of occiptal lobe where simple features of the stimulus are extracted
Proceed to complex map of stimulus onto occital cortex leading to comprehension of what is being seen
131
What happens if occipital lobe is damaged?
Person with partial or complete blindless
Info still enter eyes which are functioning as normal
But without the ability to process and make sense of information at the level of cerebral cortex the information is as good ad lost
132
What is parietal lobe?
Located at the front of the occipital lobe
Carries out functions that include processing information about touch
Contains somatosensory cortex (outer layer of pariteral lobe containing representation of the body)
Each part of somatosensory cortex maps onto particular part of body
If body area is more sensitive larger part of somatosensory cortex is deovated to it
e.g part of samtosensory cortex that corresponds to lips and tongue is larger than area for feet
133
What does motor cortex initiate?
Voluntary movememnts and sends messages to basal ganglia , cerebellum and spinal cord
Motot and somatosensory corticies are sending and receiving areas of the cerebral cortex taking in information and sending out commands as the case might be
Type of premotor neuron seems to be capable to more socially relevant coordination for communication
Around one in ten neurons in motor cortex classified as mirror neurons
134
What are mirror neurons?
Cells that are active when performing an action onself or when observing the same action performed by another
discovery have neural basis for how we imitate and copy each other - important social skills
135
Where it temporal lobe located?
Lower side of each hemisphere
Responsible for hearing and language
Auditory cortex in temporal lobe is analogous to somatosensory cortex in parietal lobe and primary visual areas of the occpital lobe
Recieves sesnory information from ears based on frequencies of sounds
Secondary areas of the temporal lobe then process info into useful units e.g speech and words
Temporal lboe house the visual association areas that interpret the meaning of visual stimuli and help us recognise common objects in the environment
136
Frontal lobe sits behind the forehead
Has specialised areas for movement, abstract thinking, planning, memory and judgement
Contains motor cortex which coordinate thought processes that help us manipulate information and retrieve memories which we can use to plan our behaviours and interact socially with others
Frontal cortex allows u to do the kind of thinking, imagining and planning that sets humans apart from most species
137
Third level of organisation in cerebral cortex involves representation of information within specific lobes in the cortex
Hierarchy of processing stages from primaryareas handling fine details of information all the way up toassociation areas
composed of nueorns that help provide sense and meaning to information registered
e.g
Primary visual cortex
Outermost layer of the occital lobe area where visual information is processed are highly specilaised
detect features of enivnroment that are in horizontal orientation others detect movement and still process information about humans vs nonhuman forms
138
What is primary auditory cortex?
Outermost layer of temporal lobe where auditory information is processed and register sound frequences
association areas of temporal lobe that allow you to turn to noises
139
Neurons in the association areas are usually less specialised and
more fliexibile than neurons in primary areas
Shaped by learning and experience to do their job more effectively
This kind of shaping of neurons by environmental forces allow the brain flexibility or plasicity
140
What is not fixed in brain?
Sensory cortices
Adapt to changes in sensory inputs
a quality researcher called plasticity ability to be molded
Functions assigned to certain areas of the brain may be capable of being resigned to other areas of brain to accommodate changing input from envirnoment
Suggests sensory inputs compete for representation in each cortical area
141
Example of plasicity
142
Phantom limbs and brain plasicity
* Limb amputated many paitents feel sensations where missing limb would be - phantom limb syndrone
* Feel missing limb moving and some report pain in their limb
* Evidence suggest that phantom limb syndrome arise due to plasticity in brain
* Experiment: Researchers stimulated skin surface in various regions around face, torso and arms while monitoring brain activity in amputees and control
* Scan displayed somatosensory cortical areas activated when skin was stimulated
* Allowed researchers to map how touch represented in somatosensory cortex for different area of the body
* e.g face touched, determine areas in somatosensory cortex most active
* Brain scans of amputees relevaed stimulating areas of face and upper arm activated area in somatosensory cortex that is previously would be activated by missing hand
* Face and arm were represented in somatosensory cortex in area adjcaent to person's ahdn now amputated
* Stimulating face or arm produced phantom limb sensations in amputees reported feeling sensation in missing limb
* Brain plasticity explain findings
* Cortical representations for face and upper arm normally lie on either side of the representation for hand
* Somatosensory areas for face and upper arm larger in amputees and had taken over the cortex normally representing hand
* New face and arm representations now adjacent to each other filling space occupied by hand representations
* Some of these new mappings ere concise
* e.g specific areas of facial skin activated in amputees, patient reported sensation in one finger of phantom limb
* Research suggests brain plasticity adaptive process and established new mappings led to novel sensations
143
Plasiciity doesn't only componestate for missing digits or limbs e.g violinists
Asymmetry in their motor and somatosensory cortex with greater activity for the region that represents left hand more dexterous than right hand
144
Asymmetry absent in non-musicians and appears to be related with movement
Similar findings with quilt makers who have highly developed areas for thumb and forefinger
Critical to their performance and taxi divers
Overdeveloped brain areas in hippocampus that are used during spatial navigation
Studies of rats and non human animals indicate that exercise such as this increases the no of synpases and promotes the development of new neurons in the hippocampus
