NEW NEURO LFGGG Flashcards
(239 cards)
1
Q
What are the 12 cranial nerves?
A
“Ooh, Ooh, Ooh To Touch And Feel Very Good Velvet. Such Heaven!”
1. Olfactory
2. Optic
3. Oculomotor
4. Trochlear
5. Trigeminal
6. Abducens
7. Facial
8. Vestibulocochlear
9. Glossopharyngeal
10. Vagus
11. Spinal accessory
12. Hypoglossal
2
Q
Week 1
Define neuroscience
A
The scientific study of the nervous system
3
Q
Week 1
What is the nervous system?
A
- Network of neurons in the brain, spinal cord and periphery
- CNS - brain and spinal cord
- PNS - nerves (cranial and spinal) and ganglia (mass of nerve cell bodies)
4
Q
Week 1
Explain the link between neuroscience and modern psychology
A
- Behaviour is initiated by the nervous system
- Therefore, neuroscience can help understand behaviour
- Advance of neuro-imaging and measures of brain function
5
Q
Week 1
History of neuroscience - prehistory
A
Neolithic
- Blunt force cranial trauma
- Cranial trepanning - 5-10% of all skulls
6
Q
Week 1
History of neuroscience - Ancient Egypt
A
- Earliest written reference to the brain (1600BC) - the Edwin Smith Surgical Papyrus
- Body and most organs preserved after death (mummification) apart from the brain
7
Q
Week 1
History of neuroscience - Ancient Greece
A
Hippocrates
- Theory of the four humours
- Brain is the source of emotion
Aristotle
- Brain not responsible for any sensations
- Emotions come from the heart
8
Q
Week 1
History of neuroscience - Roman Empire
A
Galen
- Brain is the ruling organ of the body
- Responsible for common sense, cognition and memory
- Discovery of ventricles fit Hippocrates’ theory of humourism
9
Q
Week 1
History of neuroscience - The Renaissance
A
Leonardo da Vinci (1452-1519)
- Sensation, cognition and memory attributed to the ‘3’ ventricles
Andreas Vesalius (1514-1564)
- Added more detail to understanding of brain structure
- Identified errors in Galen’s anatomy
René Descartes (1596-1650)
- Fluid-mechanical theory of brain function
- Reflexive theory
- Dualism
10
Q
Week 1
History of neuroscience - 18th & 19th Centuries
A
Key insights:
1. Nerves are wires
2. Localisation of specific brain functions
3. The neuron
4. Evolution of the brain
11
Q
Week 1
History of neuroscience - 18thC & 19thC - Nerves are Wires
A
Luigi Galvani (1737-1798)
- Stimulation of nerves in frogs caused muscle contraction
Hermann von Helmholtz (1821-1894)
- Human physiology is subject to the laws of nature
- Measured speed of nerve conduction
- ~90 ft/sec
- Slow - not just electrical, but physiological
12
Q
Week 1
History of neuroscience - 18thC & 19thC - Localisation of Specific Brain Functions
A
Johannes Müller (1801-1858)
- Proposed the ‘law of specific nerve energies’
Marie-Jean-Pierre Flourens (1794-1867)
- Experimental ablations
- Intellect = cerebral cortex
- Lower brain = vital bodily funtions
- Cerebellum = coordination and motor control
Paul Broca (1824-1880)
- Damage to left frontal cortex = difficulties in language production
Gustav Fritsch & Eduard Hitzig
- Muscle contractions contralateral to brain hemisphere
13
Q
Week 1
History of neuroscience - 18thC & 19thC - The Neuron
A
Camillo Golgi (1843-1926)
- Invented a new staining technique
- Proposed ‘reticular theory’
Santiago Ramón y Cajal (1852-1934)
- Worked out neural circuitry of many brain regions
- Proposed the ‘neural doctrine’
14
Q
Week 1
History of neuroscience - 18thC & 19thC - Evolution of the Brain
A
Charles Darwin (1809-1882)
- ‘On the Origin of Species’ (1859) considered a foundation of evolutionary biology
- Natural selection
- Also attributed to Alfred Russel Wallace
15
Q
Week 1
Define evolution
A
Gradual change in the structure of physiology of a species - generally producing more complex organisms - as a result of natural selection
16
Q
Week 1
Vertebrate brains
A
- All similar in organisation
- All have a forebrain, midbrain and hindbrain
- Brain areas may be specialised in distinct ways in response to environmental constraints
17
Q
Week 1
Name the 3 ways the human brain has evolved
A
- Brain size has increased
- Proportions of brain areas have changed
- Folding of the cerebral cortex has increased
18
Q
Week 1
Brain size and proportion
A
- Brain size has increased
- There is no link between brain size and behavioural complexity (e.g., shrews)
- There is a relationship between proportional brain size and complexity of behaviour
- The human brain is proportionally larger than any other large animal
19
Q
Week 1
Evolution in Hominids - 5 stages
A
- Australopithecus robustus
- Homo habilis
- Homo erectus
- Homo sapiens neanderthalensis
- Homo sapiens sapiens
20
Q
Week 1
Evolution in Hominids - foreheads
A
- Humans have high-straight foreheads
- These replaced the prominent brow ridges of ancestors
- Due to expansion of the cortex, especially the prefrontal cortex
21
Q
Week 1
Brain proportions
A
- Humans’ brain proportions are different than any other primates
- Differences in evolutionary development of parts of the brain have more effect on behaviour than brain size
22
Q
Week 1
The neocortex
A
- Size increased in primates
- Flexible & almost infinite learning abilities
- Reflects growing complexity of social lives
- Growth of certain parts of the cortex are responsible for social skills (e.g., language) because they improved this ability
23
Q
Week 1
The prefrontal cortex
A
- Developed greatly in primates
- Primarily responsible for motor control in other species
- Responsible for planning and abstract reasoning in humans
- Humans’ superior abilities are attributable to other specialised cortical regions and denser interconnections between the prefrontal cortex and the rest of the brain
24
Q
Week 1
Why are humans’ brains so big?
A
- Larger volume of white matter in PFC (compared to most other primates)
- White matter provides greater connectivity between PFC and the rest of the brain
- Connectivity is vital for working memory functioning
25
Week 1
Brain folding
- Increase in cortex folding has been a major factor in brain evolution
- Increases the cortical surface area that can fit inside the skull
- Allows for better organisation of complex behaviours
26
Week 2
CNS: Structure of the spinal cord
- Continuous with brain stem
- Long conical structure
- Thickness of an adult's pinkie
- Mediates transmission of information between the brain and body
- Protected by vertebrae (24 vertebra)
- Core of grey matter surrounded by white matter
27
Week 2
CNS: Function of the spinal cord
- Coordinating certain reflexes
- Conduit for sensory and motor information
- Messages between body and brain
28
Week 2
CNS: Spinal nerves in spinal cord
- Spinal nerves split into dorsal and ventral roots before entering the spinal cord
- Afferent neuron axons enter in the dorsal root and terminate in the dorsal horn
- Efferent neuron axons have a cell body in the ventral horn and leave through the ventral root
29
Week 2
PNS: Function
- Connects CNS to limbs and organs via cranial and spinal nerves
- Carries information from environment to CNS (afferent neurons)
- Carries information from CNS to muscles and glands (efferent neurons)
30
Week 2
PNS: Nerves
- Neuron axons grouped into bundles
- Only present in the PNS
- 43 pairs
- 12 cranial nerve pairs
- 31 spinal nerve pairs
31
Week 2
PNS: Cranial nerves
- 12 pairs
- 10 -> brainstem
- I & II -> forebrain
- Information between the brain and body above the neck
- Exception: Vagus nerve
32
Week 2
PNS: Spinal nerves
- 31 pairs
- Each pair is associated with a particular segment of the spinal cord
- Named dependent on the vertebral level they attach
- Spinal nerves can contain sensory & motor fibres
33
Week 2
PNS: Divisions
PNS
v
Somatic & Autonomic
v (Autonomic to...)
Sympathetic, Parasympathetic. Enteric
34
Week 2
Somatic NS
- Voluntary control of movement
- Receives sensory information and controls spinal nerves that innervate skin, joints and muscles
- Neurons are excitatory
35
Week 2
Afferent neurons
Carry sensory information from skin (sensory neuron)
36
Week 2
Efferent neurons
Control skeletal neurons (motor neurons)
37
Week 2
Which type of neuron carries sensory information from skin/are sensory?
Afferent neurons
38
Week 2
Which type of neuron control skeletal muscles/are motor neurons?
Efferent neurons
39
Week 2
Autonomic NS
- Controls involuntary functions and internal environment
- Afferent neurons carry sensory information from internal organs to CNS
- Efferent neurons control smooth muscle, cardiac muscle and glands
- Neurons are excitatory or inhibitory
- Three sub-divisions:
- Sympathetic
- Parasympathetic
- Enteric
40
Week 2
ANS: Sympathetic NS (SNS) Functions/Mechanisms
- Coordinates fight-or-flight
- Any responses for activities which expend energy
- Increase heart rate & blood pressure
- Depress digestive functions
- Mobilise glucose reserves
41
Week 2
ANS: Parasympathetic NS (PSNS) Functions/Mechanisms
- Coordinates rest and relax response (AKA rest and digest)
- Any response for activities involved with increase in the body's supply of stored energy
42
Week 2
ANS: Enteric NS (ENS) Functions/Mechanisms
- 'Second brain'
- Lines gastrointestinal tract from oesophagus to rectum
- Main role is controlling digestion
- Swallowing
- Release of enzymes
- Control of blood to facilitate nutrient absorption
43
Week 2
Neurons - Functions
- Transmit information to other neurons, muscles cells, or gland cells
- 80% are in the brain
44
Week 2
Neurons - Components (7)
- Dendrites
- Nucleus
- Cell body
- Nodes of Ranvier
- Myelin sheath
- Schwann cells
- Axon terminal
45
Week 2
Sensory neurons
- Part of PNS
- Contain sensory receptors for detecting changes
- Sends information about changes to CNS
- Cell body in PNS, axon enters CNS
46
Week 2
Interneurons AKA RELAY NEURONS KEEP TS SIMPLE
- In CNS
- Receive information from sensory neurons
- Send information to motor neurons
- Integrate/change signal:
- Integrate: inputs from several afferent neurons - average
- Change: interneurons can provide excitatory or inhibitory signals
47
Week 2
Motor neurons
- Part of PNS
- Synapses to skeletal muscle to command movement or onto glands to release hormones
- Relays signal from CNS to PNS
- Dendrites & cell body in CNS, axon enters PNS
48
Week 2
Neuronal membrane
- Made of two layers of lipid molecules - phospholipid bilayer
- Lipid molecules:
- Hydrophilic heads
- Hydrophobic tails
- Barrier: water soluble molecules cannot pass through
- Particularly impermeable to ions
49
Week 2
Fluid environment & relevant ions
- Fluid environment containing ions
- Intracellular fluid
- Extracellular fluid
Cations
- Sodium (Na+) - predominantly extracellular
- Potassium (K+) - predominantly intracellular
Anions
- Chloride (Cl-) - predominantly extracellular
- Organic ions (A-) - only intracellular
50
Week 2
Causes of ion movement
- Concentration gradients - diffusion
- Electrical force - electrostatic pressure
51
Week 2
What is diffusion?
Movement of ions from an area of high concentration to an area of low concentration - down the concentration gradient
52
Week 2
What is electrostatic pressure?
Movement of ions based on their electrical charge - opposite charges attract, same charges repel
53
Week 2
Describe the electrical polarity of neurons
- Neurons are polarised - negatively charged at rest compared to extracellular fluid
- -70mV
- While there is a difference, an electrical force tends to move ions across the membrane
54
Week 2
Membrane border guards
- Specialised proteins (channels and pumps) allow ion transport through the bilayer
Ion channels (leak channels)
- Passive ion-specific, allowing ions to rush down gradients of concentration and electrical potential
Ion pumps
- Active energy-consuming, transporting ions against gradients via active transport, maintaining and building gradients
55
Week 2
Are ion channels or ion pumps slower?
Ion pumps - require energy
56
Week 2
Define net force
- The combination of two forces that transport ions across the membrane: concentration & charge
57
Week 2
When do ions stop moving?
When opposing forces are equal - equilibrium
58
Week 2
Describe the movement of Potassium ions (K+)
Diffusion
- K+ highly concentrated in cell - want to move out and down the concentration gradient
- At rest, K+ leak channels allow ions to leave
- Inside the cell becomes more negative
Electrostatic Pressure
- Not many K+ ions move out
59
Week 2
Describe the movement of Chloride ions (Cl-)
Diffusion
- Cl- highly concentrated outside cell - want to move inside and down concentration gradient
Electrostatic Pressure
- Inside of the cell is negatively charged
- Cl- also wants to move out to repel negative charge
Net Force
- Stays where it is
60
Week 2
Describe the movement of Sodium ions (Na+)
Diffusion
- Highly concentrated outside cell - wants to move inside down concentration gradient
Electrostatic Pressure
- Inside cell is negatively charged
- Na+ ions want to move into cell due to charge attraction
Net Force
- Sodium ions move into cell (few sodium channels so ion movement is slight)
61
Week 2
Sodium/Potassium Pump
- Membrane proteins continually push Na+ out of the neuron
- Na+ ions are replaced with K+ ions
- Net movement of positive ions out - helps maintain negative charge of intracellular fluid
- Requires energy from ATP
62
Week 2
Resting membrane potential
- Membrane is permeable to K+ at rest, so K+ ions move
- K+ ion movement stops one opposing forces reach equilibrium
- Results in unequal distribution of positive and negative ions on the inside and outside of the membrane
- -70mV
63
Week 2
The Nernst Equation
- The electrostatic force required to balance the concentration gradient
- Different for each ion, dependant on Faraday's constant, gas constant, temperature, and ion valence (charge)
64
Week 2
How do the Nernst equation and the Goldman-Hodgkin-Katz equation?
The G-H-K equation has additional ions and the addition of a P variable (membrane permeability constant)
65
Week 2
Define an action potential
A brief electrical impulse that provides the basis for conduction of information along an axon - created when ion channels open, and ions rush across the membrane
66
Week 2
Describe the 3 phases of an action potential
1. Depolarisation: inside becomes more positive (towards 0)
2. Repolarisation: inside becomes more negative
3. Hyperpolarisation: more negative than at rest
67
Week 2
Describe the process of triggering an action potential
- A stimulus causes small depolarisation
- The size of the depolarisation is proportional to the size of the stimulus
- An AP occurs automatically if depolarisation reaches threshold (~ -55mV)
68
Week 2
Name the 2 ways in which a neuron can be stimulated
- Another neuron
- Sensory input (sensory neurons)
69
Week 2
Describe the features of an action potential
- 'All-or-nothing' phenomenon - AP only occurs if threshold is reached
- Large change in membrane potential (-70mV to +30mV)
- Standard size and shape
- Very rapid (1-4 ms)
- Frequent (hundreds per second) - depending on stimulus intensity
70
Week 2
What regulates the strength of a response?
- APs are subject to an all-or-nothing law
- The strength of a response is not dictated by the size of a single AP
- Strength is a function of the 'rate' law
- Rate of neural firing
71
Week 2
Voltage-gated channels
- Activated by changes in the charge of membrane
- Two types are important for APs:
- Voltage-gated Na+ channels
- Voltage-dependent K+ channels
NOTE: Channels not pumps - movement is rapid rather than slow
72
Week 2
Describe the process of an action potential (5)
1. Voltage-gated Na+ channels open, influx of Na+ -> more positive
2. Na+ channels become refractory at peak
3. Voltage-gated K+ channels open, K+ efflux -> less positive
4. Open K+ channels allow outflow
5. Overshoot caused by slow closing K+ channels
73
Week 2
Describe how the resting potential is restored
- The Na+/K+ ATPase pump moves 3 Na+ out and 2 K+ in
- The pump keeps the Na+ ion concentration low in the neuron
- K+ also diffuses back into the neuron
- This re-establishes the resting membrane potential
74
Week 2
Describe AP propagation
- Movement of AP across a neuron
- Signal travels from cell body to axon terminals
- AP first generated in axon hillock
- Na+ ions spread away from site of AP, depolarising the nearby area (more positive)
- This triggers another AP in this nearby area
- APs are triggered one after another all the way to the axon terminals
- If an axon branches, each branch continues the AP
- AP always stays the same size
75
Week 2
Describe the refractory period
- Prevents an AP from travelling backwards
- Determines upper limit on AP frequency
Two types:
- Absolute happens first - voltage-gated Na+ channels are inactivated for a short duration (~1 ms), preventing another AP from being produced
- Relative follows - voltage-gated Na+ channels are closed but no longer inactivated, but K+ is still flowing out, causing hyperpolarisation for ~2-4 ms, meaning only a very strong stimulus can produce an AP
76
Week 2
Describe synapses
- NTs are released from vesicles in terminal ends of an axon
- Excite, inhibit or modulate postsynaptic cell
- 2 (or more) NTs released from each neuron
77
Week 2
Name the 7 neurotransmitters we've studied
- Acetylcholine
- Serotonin
- Dopamine
- Nor/epinephrine
- Endorphins
- GABA
- Glutamate
78
Week 2
Acetylcholine
- Excitatory
- CNS and PNS
- Released by neurons in ANS
- Regulates heart rate, blood pressure and gut mobility
- Plays a role in muscle contractions, memory, motivation, sexual desire, sleep and learning
- Imbalances linked with Alzheimer's, seizures and muscle spasms
79
Week 2
Monoamines - serotonin
- Inhibitory
- Regulates mood, sleep patterns, libido, anxiety, appetite and pain
- Imbalances include SAD, anxiety, fibromyalgia and chronic pain
- Medications include SSRIs and SNRIs
80
Week 2
Monoamines - dopamine
- Reward system including feeling pleasure, heightened arousal, and learning
- Facilitates focus, concentration, memory, sleep, mood and motivation
- Dysfunctions include Parkinson's, schizophrenia, bipolar, restless legs syndrome, and ADHD
- Acted on by many highly addictive drugs (cocaine, methamphetamines)
81
Week 2
Monoamines - epinephrine and norepinephrine
- Responsible for fight-or-flight
- Stimulate body's response by increasing heart rate, breathing, blood pressure, blood sugar, blood flow to muscles, heightened attention and focus
- Excess can lead to high blood pressure, diabetes, heart disease and other health problems
- As a drug, used to treat anaphylaxis, asthma attacks, cardiac arrest and severe infections
82
Week 2
Peptides (endorphins)
- Pain relievers
- Play a role in perception of pain and 'feel-good' feelings
- Low levels may play a role in fibromyalgia and some types of headaches
83
Week 2
Amino acids - glutamate
- Most common excitatory NT
- Most abundant NT in brain
- Key role in cognitive functions like thinking, learning and memory
- Imbalances are associated with Alzheimer's, dementia, Parkinson's and seizures
84
Week 2
Amino acids - GABA
- The most common inhibitory NT of the nervous system, particularly in the brain
- Regulates brain activity to prevent problems in areas of anxiety, irritability, concentration, sleep, seizures and depression
85
Week 3
Meninges
- Tough connective tissue covering the CNS and some of the PNS
- Dura mater - out layer, thick, tough, flexible but not stretchable
- Arachnoid membrane - middle layer, soft and spongy
- Pia mater - clings to surface of brain and spinal cord, thin and delicate, smaller surface blood vessels found here
- Subarachnoid space - fluid-filled space between arachnoid membrane and pia mater, cushions brain
86
Week 3
How do the meninges differ between the CNS and PNS?
CNS
- 3 layers: dura mater, arachnoid membrane, pia mater
PNS
- Two layers fuse - dura and pia mater
- Sheath protects spinal and cranial nerves, and automatic ganglia
- Arachnoid membrane (CSF) not present
87
Week 3
Ventricular system
- Ventricles - hollow spaces within the brain, filled with CSF
- Interconnected
- CSF - clear fluid similar to blood plasma
88
Week 3
Describe the 4 ventricles of the brain
Lateral ventricles - sited in the centre of the telencephalon, the largest
3rd ventricle - sited at the midline in the centre of the diencephalon
Cerebral aqueduct - long tube in the mesencephalon connecting 3rd and 4th ventricles
4th ventricle - found between cerebellum and pons
89
Week 3
What are the two central functions of the brain ventricles?
1. Production and flow of CSF
2. Protection of the CNS and maintenance
90
Week 3
Describe cerebrospinal fluid
- Extracted from blood
- Consists of ions, water, protein and glucose
- Produced constantly from choroid plexus
- Total volume is ~125 ml
- Takes 3 hrs for half to be replaced
91
Week 3
Describe how CSF is produced
- Produced by the choroid plexus
- Found in the lateral ventricles, epithelium and ependymal cells
92
Week 3
Why is the choroid plexus designed to produce CSF?
- Tissue with very rich blood supply
- Protrudes into ventricles
93
Week 3
Describe the process of CSF flow (5)
- Produced by choroid plexus of lateral ventricles
- Flows to 3rd ventricle where more is produced
- Flows through cerebral aqueduct to 4th ventricle
- Leaves ventricles to subarachnoid space around CNS
- Reabsorbed into blood stream through arachnoid granulations
94
Week 3
What are the 4 vital functions of CSF?
1. Protection (reduce shock from sudden head movements)
2. Buoyancy (reduces weight of brain by allowing it to 'float')
3. Waste reduction (immunological protection - removes waste/harmful chemicals, particularly during sleep)
4. Transport (of hormones through brain)
95
Week 3
Describe hydrocephalus
- Accumulation of CSF within the cerebral ventricles
- Leads to ventricular dilation
- Classified into two types:
- Obstructive (caused by blockage)
- Communicating (reduced absorbance of CSF by arachnoid villi)
96
Week 3
Glia
- Supporting cells of the nervous system
- Several types:
- Astrocytes
- Microglia
- Oligodendrocytes
- Schwann cells
97
Week 3
Glia: Astrocytes & phagocytosis
- Physical support - 'neuron glue'
- Nourish neurons: wrap blood vessels to receive, store and release nutrients
- Help control chemical composition of extracellular fluid
- Surround & isolate synapse (limit NT dispersion)
Phagocytosis
- Cleans up debris (e.g., dead cells) in the brain
- Special astrocytes move around CNS, engulfing & digesting debris
- Form scar tissue in place of dead tissue
98
Week 3
Describe Amyotrophic lateral sclerosis (ALS)
- Most common form of motor neuron disease
- Attacks nerve cells
- Rapidly progressive, leading to fatality
- Lose all voluntary muscle control, including respiration
99
Week 3
How are astrocytes linked to memory?
- Help orchestrate and mediate synaptic activity
- This is the basis of how we learn, think and remember things
100
Week 3
Glia: Microglia
- Smallest glial cells
- Phagocytes
- Representative of immune system in brain - protect brain from invading microorganisms
- Primarily responsible for inflammatory response to brain damage
- Thought to have a role in neurodegenerative disorders and viral infections (HIV)
101
Week 3
Glia: Oligodendrocytes and Schwann cells
- Schwann cells (PNS) - wrap individual axons
- Oligodendrocytes (CNS) - wrap several axons
- Contain fatty tissue (myelin) that wraps around neuron axons
- Forms insulating coating - myelin sheath
102
Week 3
Brain blood supply
- Brain receives 15-20% of body's blood supply
- Nutrients and oxygen carried to brain by blood vessels
103
Week 3
What are the two main functions for blood in the brain?
1. Brings materials necessary for brain function (oxygen, nutrients, hormones)
2. Removes materials - CO2, lactate, hormones, ammonia
104
Week 3
Describe the blood-brain barrier
- Semi-permeable
- In most parts of the body, capillaries are lined with endothelial cells
- Small spaces exist between each so substances can move across capillary walls - these gaps are not present in the brain
105
Week 3
What are the 3 vital functions of the BBB?
- Protects the brain from foreign substances
- Protects from hormones and NTs from the rest of the body
- Maintains a constant environment - keeps the blood the same so the brain can do its job
106
Week 3
What can and cannot cross the BBB?
- Lipid soluble molecules can penetrate through relatively easily via lipid membranes of cells
- Water soluble molecules can only use specialised carrier-mediated transport mechanisms
- Active transport allows some substances across, e.g., glucose transporters
- Barrier is weak in some areas - within this is the chemoreceptive zone which detects poisons in the blood and can induce vomiting
107
Week 4
Describe the process of synaptic transmission (6)
1. AP arrives at axon terminal, triggering Ca2+ ions to move into cell
2. Ca2+ ions cause the migrations of vesicles containing NTs to the pre-synaptic membrane
3. The vesicles fuse to the pre-synaptic membrane and break open, emptying the NTs into the synaptic cleft - exocytosis
4. NTs diffuse across the synaptic cleft towards the post-synaptic membrane
5. NTs bind to receptor sites on the post-synaptic membrane with lock-and-key specificity
6. This binding opens NT-dependent ion channels which change the excitability of the post-synaptic cell, making it more or less likely to fire an AP
108
Week 4
Describe the two types of postsynaptic receptors
Direct (ionotropic)
- Binding site for a NT
- Ion channel opens when NT *molecule* binds
Indirect (metabotropic)
- Only a binding site for the NT itself
- Activates enzyme
- Ion channel opens elsewhere
109
Week 4
Describe the process/change in postsynaptic potential
Postsynaptic potential - ions move across post-synaptic membrane and alter the membrane potential
- Depolarising (excitatory) - increased AP likelihood
- Hyperpolarising (inhibitory) - decreased AP likelihood
- Signal converted from chemical to electrical
110
Week 4
Na+ Channels
- Na+ channels open
- Na+ move into neuron
- Depolarisation increases AP likelihood
- Produce excitatory postsynaptic potentials
111
Week 4
K+ Channels
- K+ channels open
- K+ leaves neuron
- Hyperpolarisation decreases AP likelihood
- Produce inhibitory postsynaptic potentials
112
Week 4
Cl- Channels
- Cl- channels open
- Rest - nothing happens, forces balance
- Depolarised - Cl- enters neuron
- Stabilisation decreases AP likelihood
113
Week 4
Describe the ways of NT removal from a synapse (3)
1. Reuptake - NT quickly pumped back into nearby glia or the axon terminal that released it
2. Deactivation - NT destroyed (inactivated) by enzymes near receptors, so it is not recognised by receptor
3. Removal - diffuses into surrounding area, e.g., blood
114
Week 4
Describe drugs (5)
- Exogenous chemicals
- Unnecessary for normal functioning
- Alter molecular functions
- Effects are physiological or behavioural
- Natural or artificial
115
Week 4
Describe agonists and antagonists
Agonists
- Facilitate or mimic action of a NT
- Facilitate postsynaptic effects
- Indirect - increase availability
- Direct - through receptor binding
Antagonists
- Inhibit action of a NT
- Block postsynaptic effects
116
Week 4
Describe the mechanisms of drug action (6)
1. Synthesis
- Altered by inactivation of enzymes (antagonist), or introduction of precursor molecules (agonist)
2. Storage
- Packaged into vesicles
3. Release
- Prevent release of NT (antagonist), or trigger NT release (agonist)
4. Receptors
- Agonists open, antagonists close
5. Reuptake
- Blocked or reduced by agonists
6. Destruction
- Myasthenia gravis - rare autoimmune neuromuscular junction disorder
117
Week 5
Describe the telencephalon
- Cerebrum
- Contains limbic system and basal ganglia
- Part of the forebrain
- Divided into symmetric left and right cerebral hemispheres - function contralaterally
118
Week 5
Telencephalon: Sub-regions
- Cerebral cortex - outer layer of neural tissue, responsible for many higher-order functions
- Limbic system - interconnected nuclei and cortical structures located in telencephalon & diencephalon important for olfaction, emotions, learning and memory
- Basal ganglia - group of nuclei located beneath cortical surface vital for movement
119
Week 5
Cerebral cortex structure
- Cortex surface enlarged 3x by folding
- Gyrus: bulges
- Sulcus: small grooves
- Fissure: large grooves
120
Week 5
Describe grey and white matter
Grey Matter
- Outer layer
- Composed of cell bodies, dendrites and ganglia
White Matter
- Inner layer composed of myelinated axons
121
Week 5
Name the four lobes of the cerebral cortex
- Frontal lobe
- Parietal lobe - perception of awareness and space, somatosensory cortex integrating all sensory systems
- Temporal lobe - auditory cortex, recognition, identification, awareness
- Occipital lobe - processing of visual information from retina
122
Week 5
Name the key functions of the prefrontal cortex
- Planning and strategies
- Executive function
- Personality
- Mood
- Language production (Broca's area)
- Coordinates voluntary movement
123
Week 5
Name and locate the 3 primary sensory cortices
- Primary visual cortex - occipital lobe
- Primary auditory cortex - temporal lobe
- Primary somatosensory cortex - parietal lobe
124
Week 5
Define lateralisation
- Two hemispheres do not perform identical functions
- Left hemisphere: information analysis, recognising serial events, controlling sequences of behaviour
- Right hemisphere: synthesis
125
Week 5
Association cortices
- Receive information from relevant primary cortices
- Sensory association cortex:
- Perception & memories
- Located behind central sulcus
- Motor association cortex:
- Directly controls primary motor cortex and thus behaviour
- Includes premotor cortex
- Located in front of PMC
126
Week 5
Describe the corpus callosum
- Large bundle of axons in the centre of the brain
- Interconnects corresponding regions of the cortex on each hemisphere
127
Week 5
The limbic system
- Cortical and subcortical structures concerned with emotions
- Hippocampus
- Amygdala
- Cingulate gyrus
128
Week 5
The limbic system: Hippocampus
- Forebrain structure of temporal lobe
- Looks like a seahorse
- Functions:
- Learning & memory
- Storing & retrieving explicit memories
129
Week 5
The limbic system: Amygdala
- In the interior of rostral temporal lobe
- Set of nuclei
- Involved in multiple aspects of emotions
- Vital for decoding emotion, particularly to threatening stimuli
- Functions:
- Fear, fear-learning & aggression
- Activation of stress response
130
Week 5
Explain the collaboration between the amygdala and hippocampus
- The amygdala receives connections from the hippocampus
- This explains why strong emotions may be triggered by memories, e.g., PTSD
131
Week 5
The limbic system: Cingulate gyrus
- Part of limbic cortex
- Located above corpus callosum
- Regulates emotions, pain and behaviours
132
Week 5
The limbic system: Mammillary bodies
- Protrusion on the bottom of the brain
- Part of the hypothalamus
- Integral to memory recollection
133
Week 5
The limbic system: Fornix
- Bundle of axons connecting the hippocampus to brain regions including mammillary bodies
- White matter bundle
- Plays a key role in cognition and episodic memory
134
Week 5
Basal ganglia
- Part of the telencephalon
- Group of subcortical nuclei
- Tightly interconnected
- Involved in control of movement
135
Week 5
Basal ganglia: Functions
- Process information from several regions of the cerebral cortex
- Returns information to the motor cortex via the thalamus
- Operates in conjunction with a loop involving the cerebellum
- Important in Parkinson's and Huntington's
136
Week 5
The diencephalon
- Division of the forebrain
- Located between the telencephalon and mesencephalon
- Surrounding the third ventricle
- Two main structures: thalamus and hypothalamus
137
Week 5
The diencephalon: Functions
- Relays sensory information (thalamus)
- Controls many autonomic functions of PNS, connect endocrine system to NS (hypothalamus)
- Involved in emotions and memories alongside limbic system (hypothalamus)
138
Week 5
Thalamus - Structure
- Largest portion of the diencephalon
- Two lobes connected by bridge of grey matter, piercing the third ventricle - 'massa intermedia' - missing in ~30% of the population
- Made up of a number of nuclei
139
Week 5
Thalamus - Function
- Receiving and relaying auditory, visual and somatosensory signals to the cerebral cortex
- Controlling states of being asleep and awake
- Motor control
- Memory and emotions
140
Week 6
Phineas Gage (1848)
- Iron rod driven through his head
- Much of the left frontal lobe destroyed
- Example of facts becoming fictionalised
141
Week 6
Auguste Deter
- Progressive cognitive impairment, hallucinations, disorientation, paranoia, and psychosocial impairment
- Autopsy revealed arteriosclerotic changes, plaques, and neurofibrillary tangles
142
Week 6
Karl Lashley and 'Mass Action' (1951)
- Found that rats trained to obtain food rewards in mazes retained memories even after progressive brain lesions
- Concluded that memories were not localised, but distributed through the brain
- Developed the principle of 'mass action' - the amount of memory loss is proportionate to the amount of brain tissue loss
143
Week 6
Wilder Penfield and the Montreal Procedure (1954)
- Used electrical brain stimulation in awake patients
- Produced vivid memories - smell, auditory, and déja vu experiences
- Results consistent with localisation of brain function
144
Week 6
Name the 4 main modern methods of neuroscience
- Histology
- Experimental ablation
- EEG
- Imaging (CT, MRI, PET, fMRI)
145
Week 6
Histology
- Visualisation of a particular brain region
- Tracing neural connections
- Efferent neurons - anterograde labelling
- Afferent neurons - retrograde labelling
146
Week 6
Experimental ablation
- Brain tissue is destroyed and alterations in behaviour are observed
- Allows identification of neural circuits and localisation of behaviour
- Lesions created by electrical currents using electrodes, or excitatory lesions created using injections of excitatory amino acid
147
Week 6
Explain the importance of sham lesions in experimental ablation
- The procedure to allow lesion creation (stereotaxic surgery) causes some damage itself
- Sham lesions must be created in a control group before any group comparisons are made
148
Week 6
Measuring electrical activity
- Acute vs chronically implanted
- Using microelectrodes:
- Single-unit recordings
- Using macroelectrodes:
- Scalp recordings, e.g., EEG/MEG
149
Week 6
Studying the structure of the brain
CT - Computerised Tomography
- Measures x-rays passed through the brain
MRI - Magnetic Resonance Imaging
- Measures magnetic field passed through the brain
150
Week 6
Measuring metabolic activity
PET - Positron Emission Tomography
- Radioactive markers
SPECT - Single Positron Emission Computerised Tomography
- Different radioactive markers
fMRI - Functional Magnetic Resonance Imaging
- Oxygen in blood vessels of brain
151
Week 6
Explain the mechanism of fMRI scans
- Uses magnetic fields to detect oxygen levels in blood
- Deoxygenated haemoglobin is more magnetic than oxygenated haemoglobin
- Brain activity requires oxygen
- Identifies brain activity by detecting changes in cerebral blood flow
- Areas that 'light up' are associated with that cognitive activity
152
Week 6
Polysomnography (PSG)
- Combines EEG with eye-movement (EOG) and muscle tension (EMG) measures to measure sleep patterns
- Sleep latency - time taken to get to sleep ('lights out' to stage N1)
- Total sleep = total(N1+N2+N3+R)
153
Week 6
Name the 4 EEG sleep stages
- Stage N1 - drowsiness, not quite fully awake
- Stage N2 - 'true' sleep, but light
- Stage N3 - deep sleep
- REM - rapid eye movement sleep
154
Week 6
Compare PSG with subjective experience
- People generally overestimate sleep latency
- People generally underestimate total sleep time
155
Week 7
Name the 3 types of muscle
- Smooth
- Cardiac
- Muscle
156
Week 7
Define a neuromuscular junction
The synapse between a motor neuron and a muscle fibre
157
Week 7
Describe the process of muscle twitch/contraction (5)
1. AP in motor neuron
2. Release of Ach
3. EPSP in muscle fibre (endplate potential)
4. AP in muscle fibre
5. Contraction (twitch)
158
Week 7
Muscle spindles
- Fibrous capsules containing specialised muscle fibres
- Detect change in muscle length
- Contractions of spindle poles keep 1a axons within the working range
- -> Contraction
159
Week 7
Golgi tendon organs
- Located at the junction of a muscle and tendon
- Innervated 1b sensory axons
- Monitors muscle tension (tendon stretch)
- -> Muscle inhibition
160
Week 7
Control of movement by the motor cortex
- Cortical structures involved in the control of movement
- The primary motor cortex (M1) - top centre of brain
- Parts of the Frontal association cortex:
- Supplementary motor area (SMA)
- Premotor cortex (PMA)
161
Week 7
Primary motor cortex
- Involved in the execution of movement
- Organised somatotopically: motor homunculus
- Input:
- Frontal association cortex
- Primary somatosensory cortex (S1)
- S1 neurons in particular location send information to the primary motor cortex area responsible for muscles in that body part
- Rapid feedback to the motor system
162
Week 7
Supplementary motor area
- Learning and planning of behaviours consisting of sequences of movements
- Damage disrupts ability to execute well-learned sequences of responses
- Pre-SMA is associated with the perception of control of spontaneous movement
- Stimulation of SMA and Pre-SMA provokes the urge to make a movement or the anticipation that a movement will occur
163
Week 7
Premotor cortex
- Learning and executing of complex movements
- Guided by sensory information
- Contains Mirror neurons
164
Week 7
Mirror neurons
MAYBE EXPLAIN IT ON THE SLIDES BITCH
I'll read up on it and fill this in dw
165
Week 7
Basal ganglia
- Part of the telencephalon
- Important for the control of voluntary movement
- Striatal nuclei receive input:
- Primary motor cortex
- Primary somatosensory cortex
- Substantia nigra
- Output
- Primary motor cortex
- Supplementary motor cortex
- Premotor cortex
- Motor nuclei of the brainstem
166
Week 7
Huntington's Disease
- Hereditary disease
- Caused by degeneration of the striatal neurons
Symptoms:
- Uncontrollable jerky limb movements
- Impaired ability to cease movements
- Cognitive and emotional change
167
Week 7
Cerebellum
- Not part of the brainstem
- Part of the mesencephalon (with Pons)
- 2 hemispheres
- Functions ipsilaterally
- Connected to brainstem via cerebellar peduncles
- Outer surface is tightly folded
168
Week 7
Cerebellum - Functions
- Involved in motor control
- Smooths and integrates ongoing movement
- Important for independent rapid skilled limb movements
- Important for postural reflexes
- Integrates movement sequences
- Partly responsible for motor learning
169
Week 7
Cerebellum - Damage
- Possible causes: stroke, haemorrhage, alcoholism, tumour, physical trauma, chronic degenerative conditions
- Cerebellar Ataxia - lack of coordination of movements
- Can manifest as difficulty walking, particularly with a narrow base (one foot in front of the other)
- Intention tremor - involuntary, rhythmic muscle contractions (oscillations) that occur during a purposeful, voluntary movement
170
Week 7
Reticular formation
- Includes a large number of nuclei in the brainstem (midbrain, pons and medulla oblongata)
- Important in a variety of motor functions:
- Regulates muscle tone
- Controls (semi)automatic responses, e.g., coughing
- Controls posture
- Plays a role in locomotion
171
Week 7
Name the 2 groups of descending motor tracts
- Lateral pathways
- Ventromedial pathways
172
Week 7
Lateral pathways
- Originate in the cortex
- Composed of 3 tracts:
- Lateral corticospinal
- Corticobulbar
- Rubrospinal
- Control voluntary independent movement of distal muscles (forearm, hand, fingers)
173
Week 7
Ventromedial pathways
- Originate in the brain stem
- Composed of 4 tracts:
- Ventral corticospinal tract
- Vestibulospinal tract
- Tectospinal tract
- Reticulospinal tract
- Controls automatic movements of proximal and axil muscles (e.g., movements related to posture and locomotion)
174
Week 8
Define sound
- Changes in air pressure produced by objects that vibrate
- Alternating compression and expansion of air molecules
175
Week 8
Outer ear
- External ear = pinna
- Protects the middle and inner ear
- Sound is funnelled through pinna and auditory canal
176
Week 8
Middle ear
- Impedance matching - increases efficiency of sound transfer into the cochlea
- Area effect: greater pressure is exerted at the oval window than at the tympanic membrane
- Lever effect: ossicles act as a lever, amplifying the force exerted on the tympanic membrane
- Middle ear reflex - muscles attached to ossicles (middle ear bones) contract when exposed to intense sounds and reduction from self-generated sounds
177
Week 8
Inner ear - two sections
- Cochlea (involved in hearing)
- Vestibular system (involved in balance)
178
Week 8
Cochlea
- Three fluid-filled canals
- Scala vestibula (upper)
- Scala media (middle)
- Scala tympani (lower)
- Organ of corti in lower canal
179
Week 8
Organ of corti
- Receptive organ
- Contains basilar membrane, hair cells and tectorial membrane
- Hair cells transform sound vibrations into neurotransmissions
180
Week 8
The auditory nerve
- 300,000 nerve endings are tonotopically organised - different fibres correspond to different frequencies
- Fibres innervating IHC responding to low frequencies are near the centre of the nerve
- Fibres innervating IHC responding to high frequencies are near the peripheries of the nerve
181
Week 8
Describe the 6 steps of the auditory pathway
1. Organ of corti (auditory nerve)
2. Cochlear nucleus (medulla)
3. Superior olivary complex (medulla)
4. Inferior colliculus (midbrain)
5. Medial geniculate nucleus (MGN; thalamus)
6. Auditory complex (temporal lobe)
182
Week 8
Auditory complex
- Hierarchical arrangement
- Core region
- Contains the primary auditory complex (A1)
- Tonotropically organised isofrequency bands
- Belt region
- First level of auditory association cortex
- Parabelt region
- Highest level of auditory association cortex
183
Week 8
Describe the differences between the two auditory processing streams (V & D)
Ventral stream
- Anterior parabelt -> anterior temporal lobe
- The what pathway
Dorsal stream
- Posterior parabelt -> posterior parietal cortex
- The where pathway
184
Week 8
Perception of loudness
- Corresponds to physical dimension of amplitude of sound waves
- Loudness signalled by the rate of firing
185
Week 8
Perception of pitch
- Corresponds to physical dimension of frequency
- Signalled by:
- Place coding - different neurons fire depending on location on the basilar membrane
- Rate (temporal) coding - information carried by the timing of the AP fired
186
Week 8
The vestibular system
- In the inner ear
- Comprised of vestibular sacs and semicircular canals
- Functions:
- Balance
- Maintenance of head position
- Eye movements for image stability
187
Week 8
Vestibular system - Vestibular sacs
- Saccule and utricle
- Sensitive to the force of gravity and inform about the head's orientation
188
Week 8
Vestibular system - Semicircular canals
- Ring-like structures that approximate the three major planes of the head (sagittal, transverse, and horizontal)
- Receptors in each canal respond to angular acceleration in one plane
189
Week 8
Somatosensory system
- A subset of the sensory nervous system
- Provides information about the surface of the body as well as the inside
Organic senses
- Provide information about pleasant and unpleasant sensations - internal organs - visceral
Proprioception and kinesthesia
- Provide sensory information about body position and movement
Cutaneous sense (skin senses)
- Commonly referred to as 'touch'
- Includes perception of temperature and pain
190
Week 8
Skin anatomy
- Consists of epidermis, dermis and subcutaneous tissue
- Variable appearance of skin
- Free nerve endings
- Encapsulated somatosensory receptors:
- Ruffini corpuscles
- Pacinian corpuscles
- Meissner's corpuscles
- Merkel's disks
191
Week 8
Perception of touch
- Touch receptors = mechanoreceptors
- Respond to vibration in the skin and changes in pressure against it
- Use large myelinated Aβ fibres (i.e., high conduction velocity)
192
Week 8
Name the 2 factors responsible for accuracy of touch sensation
- Density of mechanoreceptors
- Receptive field size
193
Week 8
Perception of temperature
- Temperature receptors = thermoreceptors
- Free nerve endings
- 'Warm' receptors
- Located deep in the skin
- Use unmyelinated C fibres
- 'Cold' receptors
- Located just beneath the epidermis
- Use unmyelinated C fibres and lightly myelinated Aδ fibres
- Some thermoreceptors respond to chemicals, e.g., menthol
194
Week 8
Perception of pain
- Pain receptors = nocireceptors
- Free nerve endings
- Pain information conveyed via unmyelinated C fibres and lightly myelinated Aδ fibres
195
Week 8
Describe the 4 types of nocireceptors
- Mechanical - sensitive to strong pressure, e.g., a pinch
- Thermal - sensitive to burning heat and extreme cold
- Chemical - sensitive to histamine
- Polymodal - respond to mechanical, thermal and chemical stimuli
196
Week 8
Describe the 2 distinct ascending somatosensory pathways
Dorsal column-medial lemniscus pathways
- Tactile sensation and proprioception
Spinothalamic pathway
- Pain and temperature sensation
197
Week 8
Somatosensory cortex
Two main cortical areas:
- Primary (S1)
- Secondary (S2)
- Somatotopic representation of the body parts
- Amount of somatosensory cortex not proportionate to body surface
198
Week 8
Components of pain perception
Sensory component (perception of intensity)
- Involving pathway to S1 and S2
Immediate emotional component (unpleasantness)
- Involving pathways including the insular cortex and anterior cingulate cortex
Long-term emotional component (chronic pain)
- Pathways to prefrontal cortex
199
Week 8
Name the 6 psychological factors influencing pain
- Previous experience
- Perceived self-efficacy
- Attention
- Anxiety
- Depression
- Perceived helplessness
200
Week 8
Olfaction
- Chemical sense
- Second to vision in number of receptor cells (10m)
201
Week 9
Explain the process of accommodation (5)
1. Enters the eye through the cornea
2. Progresses through the pupil
3. Bend by the lens (image reversed and inverted
4. Continues through the vitreous humour (clear gel)
5. Projected onto the retina
202
Week 9
The structure of the retina
- Photoreceptors - convert light energy into neural activity
- Bipolar cells - transmit information to ganglion cells
- Ganglion cells - integrate information and send APs to brain
- Horizontal and amacrine cells - lateral neurites influence cells close by
203
Week 9
Describe the differences between the 2 types of photoreceptor cells
Rods
- 92 million
- Found mainly in retinal periphery
- Very sensitive to light
- Monochromatic information
- Poor acuity
Cones
- 4.6 million
- Found mainly in the fovea
- Less sensitive
- Provide information about hue
- High acuity
204
Week 9
Describe the process of transduction
- A process that converts an external stimulus to an internal stimulus
- Transduction of light energy into changes in membrane potential
205
Week 9
Receptive field
- The area of the visual space in which a stimulus must be presented in order to change the activity of a neuron
- The size of a neuron's receptive field determines its acuity (smaller is better) and sensitivity (larger is better)
- Fovea: small, as few photoreceptors converge on ganglion cell
- Periphery: large, as many receptors converge
206
Week 9
Retinofugal projections
Visual information from the eye transmitted to the visual cortex
207
Week 9
Visual (hemi)field
- Each eye has an optic nerve
- Nasal half of axons cross to opposite hemisphere
- Lateral half of axons stay on same hemisphere
- Axons cross at optic chiasm
208
Week 9
Lateral geniculate nucleus
- Where our optic tracts feed into and end
- Each receives information from both eyes, but only about the contralateral visual field
- 6 specialised layers, innervated by the contralateral layers (1, 4 and 6) and ipsilateral (2, 3 and 5) eye
209
Week 9
LGN - Layers 1 & 2
Magnocellular - relay information about form, movement, depth, light-dark contrast
210
Week 9
LGN - Layers 3 to 6
Parvocellular - relay information about colour (red & green) and fine detail
211
Week 9
LGN - Sublayers
Koniocellular - relay information about colour
212
Week 9
The striate cortex
- AKA the primary visual cortex (V1)
- Cortical region organised into 6 layers
LGN
v
Striate cortex
v
Extrastriate cortex
213
Week 9
The extrastriate cortex
- Surrounds the striate cortex
- Combines information for perception
- Arranged hierarchically (V2-V8)
- Information moves up the cortices to be analysed
214
Week 9
Describe the 2 pathways/processing streams of the extrastriate cortex
Dorsal - 'where'
Ventral - 'what'
215
Week 9
Name the 2 systems of colour perception
Trichromatic coding (cones)
Opponent-processing coding (ganglion cells)
216
Week 9
Trichromatic coding
- Retina contains three types of cones responsible for colour vision:
- Blue (short nm)
- Green (medium nm)
- Red (long nm)
- Red-green colourblindness is caused by a genetic defect resulting in 'red' cones being filled with 'green' cone pigment, or vice versa
217
Week 9
Opponent-process coding
- Three-colour system is converted into opponent-colour system
- 2 types of colour-sensitive ganglion cells, respond to colour pairs (blue & yellow, green & red)
218
Week 9
Negative afterimage
- Due to adaptation in the rate of firing of ganglion cells
- If ganglion cells are excited/inhibited for a prolonged time, they will fire less/more relative to baseline activity - a rebound effect
219
Week 10
Teaching chimpanzees language
- Attempts currently unsuccessful
- Larynx is higher and closer to mouth, restricting possible range of sounds
- Gestures may be used in a more sophisticated way
220
Week 10
Define aphasia
Difficulty producing or comprehending speech, caused by brain damage rather than deafness or motor deficit
221
Week 10
Lateralisation of language
- Language is mostly lateralised
- Left is dominant for speech in 90% of the population
- Right side is dominant in 27% of left-handed people and 15% of ambidextrous, but only 4% of right-handed
222
Week 10
Neuroanatomy of language (3)
- Broca's area - important in language production
- Wernicke's area - important in language comprehension
- Auditory cortex
223
Week 10
Language comprehension
- The brain works like a dictionary
- Audio and visual
- We look up words based on how they look and sound (Wernicke's area)
- Memories associated with words are activated (via posterior language area)
224
Week 10
Comprehension of metaphors
- Likely involves more of the right hemisphere
- This probably extends to the comprehension of moral stories
225
Week 10
Bilingualism
- Different languages are processed in different areas of the brain, with some overlapping
226
Week 10
Voice recognition
- Speech conveys information beyond the meaning of the words, e.g., age and gender
- Phonagnosia - impaired voice discrimination abilities
227
Week 10
Name the 4 forms of aphasia
1. Broca's (non-fluent)
2. Conduction
3. Wernicke's (fluent)
4. Anomic
228
Week 10
Broca's aphasia
- Damage to inferior left frontal lobe
- Comprehension of speech intact
- Speech is slow, non-fluent, costs effort
- Content words still used - nouns & verbs
- Function words are more difficult - e.g., articles
229
Week 10
Describe the 3 speech deficits in Broca's aphasia
1. Agrammatism - difficulty in use of grammatical constructions
2. Anomia - word-finding difficulties
3. Articulation problems - mispronunciations
230
Week 10
Conduction aphasia
- Characterised by meaningful fluent speech and comprehension, but poor repetition
- Caused by damage to pathway between Broca's and Wernicke's - arcuate fasciculus
- Synonyms often used
231
Week 11
Define neuro-control/regulation
Functional integrations between networks of neurons that regulate/control a behaviour/function
232
Week 11
Neural control of breathing
- Controlled by the brainstem
- Dorsal respiratory group is located in the distal portion of the medulla
- When more air is needed, innervation of external intercostal muscles increases lung volume
233
Week 11
Hypothalamus function
- Hormone production
- Primary function is homeostasis
- Organises survival behaviours
234
Week 11
The pituitary gland
- Attached to the base of the hypothalamus via the pituitary stalk
- Two main lobes - anterior & posterior
- Anterior is considered the 'master' gland
235
Week 11
Communication between the hypothalamus and pituitary gland
Anterior pituitary gland (indirect) = hormones
Posterior pituitary gland (direct) - synaptic transmission
236
Week 11
Hypothalamic Pituitary Axis (HPA) (4)
- Paraventricular nucleus of hypothalamus secretes corticotropin-releasing hormone (CRH)
- Stimulates anterior pituitary gland to release adrenocorticotropic hormone (ACTH)
- Enters blood and stimulates adrenal cortex to release cortisol
- The stress response
237
Week 11
Cortisol and epigenetics
- Stress responses seem to be altered by the environment and epigenetics
- Alteration in the expression of genes due to nurture
- Rat studies (nurturing/negligent mothers)
238
Week 11
Sexual behaviour
- Spinal areas involved - lumbar region
- Medial preoptic area in males
- Ventromedial nucleus of hypothalamus (VMH) in females
- Medial amygdala receives chemosensory information from the vomeronasal system and somatosensory information from the genitals
- Mediates signals to the midbrain and medulla
239
Week 11
Eating behaviour
Hypothalamus
- Role in hunger (lateral) - signalled by ghrelin
- Role in satiety (ventromedial) - signalled by leptin
