Neurophysiology Flashcards
Nerve type
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Afferent
Nerve type
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Efferent nerve
Autonomic nervous system
Visceral motor (involuntary) function
Somatic nervous system
Somatic motor (voluntary) function
Glial cells
- Non-neuronal cells
- Provide support + nutrition
- Form myelin
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What characterises a neuron?
- Electrical excitability
- Presence of synapses
Name the three parts of a typical neuron
- Soma/body
- Dendrites
- Axon
The axon leaves the soma at the…
Axon hillock
Give the 5 functions of glial cells on neurons
- Secure
- Supply oxygen + nutrients
- Insulate between neurons
- Destroy pathogens
- Remove dead neurons
Resting membrane potential
- Potential gradient
- Between IC space and EC space
The potential of the IC space is…
Negative
Steps toward depolarisation of a cell
- Positive IC charge
- Decreased PD between IC and EC
Give the potential difference found between the IC + EC space of a neuron
-75mV
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- Na+: 140
- K+: 5
- Ca2+: 2.5
- Cl-: 100
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- Na+: 14
- K+: 95
- Ca2+: μmol/l
- Cl-: 3
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ATPase pump
- Na+ out
- K+ in
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K+
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Na+
RMP is a result of…
Outflow of K+ ions
Give the aim of the ATPase pump in the neuron cell membrane
Maintain concentration gradient
Which equation is used to calculate the change of permeability of a neuron
Goldman-Hodgkin-Kats (GHK) equation
EK
Potassium equilibrium potential
The lipid bilayer of a cell functions as an electrical…
Insulator
Ions pas via the channels
1
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Channel domains
2
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Outer vestibule
3
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Selectivity filter
5
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Phosphorylation site
Hyperpolarisation never evokes…
Action potential
Local response
A potential change remaining under a threshold
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What is conduction with decrement?
- The farther the recording electrode from the stimulation site
- The smaller the potential change which reaches the electrode
Give the types of synaptic signals?
- Excitatory
- Inhibitory
Source of action potential
Voltage-dependent ion channels
Sodium influx persist until depolarization reaches…
15-30mV
Give the process
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- MP at -70mV (RMP)
- Stimulus → MP raised to -55mV (Threshold potential)
- MP raises to +40mV
- Potential drops + overshoots to -90mV
- MP at -70mV (RMP)
‘All or nothing’ law
The strength at which a nerve responds to a stimulus is independent from stimulus strength
Tetrodotoxin (TTX)
- Fish toxin
- Blocks voltage-dependent sodium channel
The specific blocker of the voltage-dependent K+ channel
Tetraethyl ammonium (TEA)
Channel is either closed or open (no inactive state)
Title the figure
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Phase 0: Stimulation
Title + Annotate the figure
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Phase 1: Threshold potential
- Voltage-dependent Na+ channel opens
Title + Annotate the figure
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- Phase 2: Overshoot, Na+ channel inactivates
- Phase 3: Plateau, slow Ca2+ influx
Title + annotate the figure
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Phase 4
- Repolarisation, K+ efflux
Title + Annotate the figure
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Phase 5: Posthyperpolarisation
- Voltage dependent Na+ + K+ channels close
- ATPase pump restores conc. gradient
Describe propagation of AP in naked fibres
- AP propagates step-by-step
- Channel activates the next channel
- Slow process
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AP decreases
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AP regeneration
Fast conduction with myelinated fibres is made possible by the fact that…
Only the nodes of Ranvier contain the TTX-sensitive sodium channels
Conduction velocity of myelinated fibres is proportional to…
Diameter of the myelin sheet
What are the classifications of nerve fibres?
- Erlanger-Gasser
- Lloyd-Hunt
Give the steps of axonal transport
- Peptides/neurotransmitters produced in the soma of the neuron
- These are then transported to the presynaptic nerve ending
Which motor proteins are involved in the movement during axonal transport?
- Kinesin
- Dynein
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Dynein + kinesin are powered by…
Hydrolysis of ATP
Kinesin transports substance…
- From the centre to the periphery
- Known as anterograde transport
Dynein transports substance…
Toward the negative end of microtubules
Compared with chemical synapses, electrical synapses are…
- Fast reflex arches
- Often bidirectional
Used to give fast responses, such as defensive reflexes
Chemical synapses usually communicate with…
Muscles or glands
Name the connection of an electrical synapse between two neurons
Gap junction
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Metabotropic effect
Long term changes by activating signalling cascades
(Via chemical synapses)
Give the steps of metabotropic effect
- Binding of ligand to the receptor
- IC second messenger
- IC metabolic (metabotropic) effect
- Long lasting depolarisation or hyperpolarisation
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Give the synaptic processes of metabotropic effect
- Facilitation
- Inhibition
- Disfacilitation
- Disinhibition
- Spatial summation
- Temporal summation
The synaptic processes of metabotropic effect can lead to which kinds of potential?
- EPSP (Excitatory postsynaptic potential)
- IPSP (Inhibitory postsynaptic potential)
Which transmitters are involved in metabotropic effect?
Metabotropic transmitters
How do ion channels alter the flow of cations/anions?
By augmenting/attenuating ion permeability
List the types of ligand-dependent ion channels
- n-ACh
- Glutamate
- Anion
- G-protein mediated
List the types of ion channel
- Leaking Na+, K+ and Cl-
- Voltage-dependent Na+ and K+
- Ligand-dependent non-selective Na+, K+ and Cl-
- Mechano receptive
- Energy sensor
What acts as a stimulus of mechanoreceptive ion channels?
Deformation of an axon terminal
What acts as a stimulus of energy sensor ion channels?
ATP concentration of a cell
Describe the structure of the voltage-dependent Na+ channel
- IC, EC and transcellular parts
- Domains I-IV
- These join to form a closed channel
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Which ion channel segment changes its conformation when the membrane potential is detected
- 4th Membrane segment of each domain
- Causes an open state of the channel
n-Ach channel is located…
- Neuromuscular junction
- CNS
n-Ach delta subunit binds…
d-tubocurarine
Give the stimulators and inhibitors of n-Ach
- Nicotine (+)
- Curare (-)
Summarise: Glutamate-dependent cation channels
- Important excitatory system
- Depolarisation after a small Na+ influx
- LTP (Long-term potentiation) found here
- Basis of learning
The opening of anion channels causes
Hyperpolarisation
Give the mediators of Anion channels
- GABA
- Glycine
In ryanodine channels, the T-tubulus/ triad is blocked by…
Dihydropyridine (DHP)
The pore-forming part of the DHP receptor acts only as a…
Voltage sensor
Title the figure
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Calcium channel in the skeletal muscle
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Ryanodine channel in the SR membrane
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DHP channel (=voltage sensor) in the T-tubulus
IP3 receptor function
Mobilises Ca2+ from IC stores
Describe Energy sensor ion channels
- Low ATP = Open channel
- High ATP = Closed
Describe the mechanism of high ATP levels on energy sensor channels
- Regulator subunit - Conformational change
- Pore-forming subunits - Conformational change
- K+ efflux terminates
- IC K+ increases
- Depolarisation
- Ca2+ influx
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The electrical stimuli applied to tissue can be described by…
- Potential
- Length of time it is applied
Adaptation
- Stimulation potential reached slowly
- The opening of Na+ channels
- Inactivation of Na+ channels
- Inhibition of Na+ influx
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Summation
- Sub-threshold stimuli applied frequently
- AP may be triggered by this weaker-than-threshold potential
- (Accumulation of cations)
Rheobase
The minimal stimulus strength that is able to generate a response
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Chronaxie
The time necessary to elicit a response if the stimulus strength is set to double the value of rheobase
Give the layers of a nerve, starting from the inside
- Axon
- Endometrium
- Perineurium
- Epineurium
Give the classifications of neurons
- Unipolar
- Bipolar
- Multipolar
- Pseudounipolar
Unipolar neuron
Dendrite + axon emerges from the same process
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Bipolar neuron
Axon + single dendrite on opposite ends of the soma
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Multipolar neuron
Two or more dendrites separate from the axon
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Pseudounipolar neuron
Unipolar, but with one divided axon
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Neural network
- Organised for complex tasks
- The function of one neuron may be influenced by the functions of others (Convergence)
- Axons of one neuron may to many other neurons (Divergence)
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Function of interneurons
- May inhibit/excite collaterals between neural pathways
- May generate returning signals (Reverberation)
Types of reflexes
- Monosynaptic: One synapse responsible
- Polysynaptic: More than two neurons responsible
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Presynaptic inhibition
Inhibition acts on the region before the second neuron
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Postsynaptic excitation
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The second neuron is influenced by the excitatory or inhibitory effects
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Disfacilitation
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Disinhibition
The spinal cord is split into which elements?
- Consciously perceived
- Somatic
- Subconscious, automatic
The simplest unit of a function is the…
Reflex
White matter + Grey Matter
- White matter: Nerve fibres
- Grey matter: Nerve cells
In a cross-section of a grey matter, what can be distinguished?
Rexed’s zones
(With the exception of the lateral horn)
Give the Rexed’s zones/fields
- I-VI = Upper horn
- VII-IX = Lower horn
- II-III → Mostly interneurons
- IX → Large motor neurons
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In Rexed’s zones, motor cells show what kind of arrangement?
Somatotopic arrangement
Describe the size principle of zones in the ventral horn
- Postural, tonic muscles are innervated by a low threshold, small neurons
- Neurons associated with complicated movements are large
Cells leaving the vertebral canal are called…
Radicular cells
List the types of radicular cell
- Somatosensory cells
- Somatomotor cells
- Sympathetic cells
- Parasympathetic cells
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Give the cells inside the grey matter
- Excitatory interneurons
- Inhibitory interneurons
Segments of the skin associated with a sensory nerve
Dermatomes
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Important for determination of the origin of skin sensitivity disturbances
Skin zones belonging to a visceral organ are called…
Head-zones
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Known as referred pain
Give the types of reflex
- Spinal cord reflex
- Cranial nerve reflex
- Primitive reflex
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Steps of a reflex arc
- Stimulus
- Sensory neuron activated
- Processing in CNS
- Motor neuron activated
- Response by effector
Reflex when the receptor is found in the same organ/muscle as the effector
Proprioceptive reflexes
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Give the main types of proprioceptive reflex
- Myotatic
- Inverse myotatic
- Stretch evoked flexor reflexes
How does the proprioceptive reflex differ from the exteroceptive reflex
- Reflex arc is monosynaptic
- No latency
- Immediate response
- No fatigue
Common features of the proprioceptive reflexes + exteroceptive reflexes
- The response has a local character
- Response intensity is proportional to stimulus
- Reciprocal innervation is typical
- Higher brain levels modulate the reflex
Myotatic (stretch) reflex receptors are located…
- 2 sites in the intrafusal fibre:
- Nuclear bag
- Nuclear chain
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The receptors of the myotatic reflex synapse directly + through excitatory interneurons to the…
- Alpha motor neuron of the corresponding extrafusal fibre
Antigravitational musculature
Extensor/flexor reflex (seen in sloth)
Reflectorial contraction
The most important connections of afferents coming from the muscle spindle…
Alpha motorneurons
Fine tuning of the myotatic reflex is completed by…
Recurrent inhibition
The function of Renshaw cells
Cause retrograde inhibition
Strong afferent effects are smoothed
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Inverse stretch/inverse myotatic reflex
- Passive stretching of Muscle → Contraction (Fusimotor system)
- Further stretching → Sudden relaxation (lengthening)
Which organs are activated in the inverse myotatic reflex?
Golgi tendon organs
The function of the inverse myotatic reflex
- Protection against overstretching and rupture
- Fine-tuning roll in normal movement
Beside Golgi tendon organs, what else can explain the myotatic reflex?
Active muscle contraction → Antagonising the fusimotor system
Flexor stretch reflex
Extension both in extensor and flexor muscles
Extensor thrust
- Pressing the sole of the foot on the ground extends the limb
- Ensures a reliable support during stepping
Exteroceptive reflexes
Reflex arc found outside of the effector organ
- Averting
- Nociceptive
- Pain avoiding behaviour
How does the exteroceptive reflex differ from the proprioceptive reflex?
- Tactile + pain receptor
- Polysynaptic
- Very long latency
- Slow response
- Easily fatigues
Give the pathway of an exteroceptive reflex
- Nociceptive/thermoreceptors → Grey matter
- Afferent activation:
- Relaxes ipsilateral extensor muscles
- Activated ipsilateral flexor muscles
- Every muscle of the joint participates
As well as the ipsilateral muscles, the exteroceptive reflex also affects…
Contralateral muscles
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How can reflexes be clinically used in the case of lesions?
- Size of the lesion can be localised
- Location of the lesion in the spinal cord can be localised
- Lesions can cause a change in the pattern of the reflex
Babinski sign in a diseased animal
- Plantar reflex (efferent has no modulating influence)
- Forelimb is withdrawn by the animal
- On the digits, instead of plantar flexion, dorsiflexion is seen
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Give the reflexes in the ‘movement patterns’ category
- Walking
- Scratch reflex
Movement patterns
- Stereotype
- They extend to more segments
- Rhythmically repeated
- They last longer than the stimulus
0
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Stimulus arrives from the sensory ganglion
1
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Adaptation to excitatory effects
2
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Spontaneous release from inhibitory effects
3
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Running toward the extensor motor neuron
4
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Running toward the flexor motor neuron
5,6
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Excitatory interneurons send collaterals to inhibitory interneurons
Sensory ascending pathways
- Travel toward the CNS
- Consist of three neurons
Motor, descending pathways contain which systems?
Somatic locomotor systems:
- Pyramidal system
- Extrapyramidal system
Give the most important ascending pathways
- Goll-Burdach
- Flechsig
- Gowers
- Lateralis et ventralis
Goll-Burdach
- Light tactile sensation, motor afferents
- Fasciculus gracilis (Goll)
- Fasciculus cuneatus (Burdach)
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Flechsig
Cerebellar muscle afferents: Dorsal spinocerbellar tract
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Gowers
Cerebellar muscle afferents: Ventral spinocerebellar tract
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Lateralis et ventralis spinothalmic tracts
Thermal and nociceptive sensory afferents
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Pyramidal tracts
Lateral corticospinal tract + Ventral corticospinal tract
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List the extrapyramidal tracts
- Rubro-spinal tract
- Vestibulo-spinal tract
- Reticulo-spinal tract
- Tectos-pinal tract
Rubrospinal tract
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Vestibulospinal tract
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Reticulospinal tract
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Tectospinal tract
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Autonomic nervous system (ANS)
- Automated control of metabolic processes
- Connection between the organism and the external environment
- Controlling:
- Smooth muscles
- Exocrine/endocrine glands
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Efferentation of the ANS is practically independent from…
The somatic motor system
Why is the ANS: Autonomic?
Essentially involuntary actions
Why is the ANS: Vegetative?
It controls the metabolism required to maintain the life of the organism
What are the ANS elements in the CNS?
Supraspinal regions
Function of the supraspinal regions
- Perception of the actual state (Afferentation)
- Processing
- Efferentation:
- Activating sympathetic, parasympathetic endocrine systems
- Responses of the behaviour
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- Processing of external stimuli
- Initiating behavioural responses
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Behavioural and emotional responses
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- Integration of internal stimuli
- Connection to the endocrine system
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- Respiration
- Circulation
- Digestion
The frontal and parietal association cortex influences…
Behavioural responses related to autonomic functions
Which cranial nerves contain afferent and autonomic neurons?
- III
- VII
- IX
- X
The PNS is built upon which features?
- Ach transmitters
- Postganglionic neurons
- Sympathetic neurons transmission by norepinephrine
- Signals can cause opposite effects on target cells (dependent on cell surface receptors)
Postganglionic neurons receive information from…
- Preganglionic neurons
- Collaterals
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Fate of ACh
- Binds to the receptor
- Metabolised by the present acetylcholinesterase enzyme
Function of the sympathetic nervous system
- Mobilisation
- Redistribution of blood
- Dilation of smooth muscle + vessels
- Redistribution of circulating blood
Title and annotate the figure
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Sympathetic postganglionic transmission
- Fibre reaches tissue
- Neurotransmitters are released in varicosities along the tissue
Main neurotransmitter for sympathetic postganglionic fibres
Norepinephrine
- Released via peptidergic synaptic co-transmission
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What occurs at the varicosity?
Place of final transmission of norepinephrine
Location of the sympathetic nervous system
Thoracolumbar spine segments
Paravertebral switch: Figure
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Prevertebral switch: Figure
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Functions of the parasympathetic nervous system
- Increase substance + energy stores
Effects are restricted to a defined area
Give the parts of the parasympathetic system
- Cranial part
- Sacral part
The longest fibres of the parasympathetic nervous system
Preganglionic fibres of the vagus nerve
The spinal parasympathetic division originates from the…
…preganglionic cells in the intermediomedial region of the sacral spinal cord
Via splanchnic nerve
Parasympathetic postganglionic transmission
- ACh release from postganglionic fibre
- Muscarinic target cell receptor receives ACh
- The effect of the ACh depends on the type of receptor (M1/2/3)
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Give the steps of sensory signal in the CNS
- Reception
- Spinal cord
- Transmission through ascending pathway
- Signal modulation
- Perception in the cortex
Pain stimuli can pass to the spinal cord via which pathways?
- Fast (A-Delta) reception
- Slow (C-fiber) (unmyelinated) reception
Pain sensation is based on which nerve endings?
Nociceptive free nerve endings
What explains the fact that slow fibres are arranged in multisynaptic connections?
Slow spreading of pain in emotional states
Rapid pain mainly elicits…
Flexor reflexes
What symptoms can be seen in slow pain responses?
- Decrease BP
- Sweating
- Nausea
Pain sensors receive which stimuli from an injury?
- Noxious stimulus (wound)
- Histamine (from basophil)
- Stretch stimulus (from blood vessel oedema)
SP =
Substance pain
Give the effect of SP
Multiplies the discharge of its own axons in many ways
E.g Oedema
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How can pain be decreased/controlled?
With Descending (opiate-mediated) pathways
- Pain stimulus is the same, only effect on pain-sensing structures decreases
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Signal modulation
- Nucl. gracilis et cuneatus
- Cross to the opposite side to thalamic nuclei
- Received by the relay (synaptic) nuclei
Give examples of relay nuclei
- VPL (Ventro postero-lateral) nucleus
- VPM (Ventro postero-medial) nucleus
VPL (Ventro postero-lateral) nucleus shows which organised arrangements?
- Somatotopy
- Co-localisation according to the modality of sensation
VPM (Ventro postero-medial) nucleus function
Receptors of the head send impulse patterns through CN-V
Nuclei which non-synapsin afferents run through are known as…
Bypass nuclei
Specific/relay system nuclei are involved in…
Relaying signals to the third order sensory neuron
- Allows the enhancement of a stimulus
Non-specific/bypass system function
Determination of the pain sensation and activation state
- Less important in the exact localisation of pain
The non-specific/bypass system receives fibres from…
Collaterals from axons travelling to the frontal cortex
From the thalamus, which two kinds of afferentation reach the cortical areas?
- Somatotopically + sensation specifically arranged fibres
- Fibres from the reticular formation
What is the basic unit of cortical representation?
The column of grey matter
Brodmann areas
Regions of the cerebral cortex in the human brain defined by its structure and organisation of cells
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Cortical somatotopy is proportional to…
The relative importance of the given area in sensation
Not necessarily the size of the area
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The secondary sensory area
Sylvian fissure
In dogs + cats, 90% of sensory formation is occupied by…
Lips, cheek and limbs
Columnar functional system
- Impulse is relayed to the cells of the columnar functional unit (usually Cajal’s double dendritic cell)
- Information is transmitted to large pyramidal cells
- Information leaves through two pathways:
- Fibres to near-by columns
- Fibres to the periphery
The column that forms a functional unit contains how many cells?
2500 cells
5% are pyramidal cells
The origin of posture and movement control are based on…
Heirarchical organisation
Neurons in the spinal cord that are involved in posture are under the control of…
Local regulatory systems supplimented by an additional supervisor, director system
The most important afferentation of posture
Vestibular apparatus
The main function of the vestibular apparatus
Support the body against gravitation
Give the order of voluntary movement hierarchy (upper motor system)
- Movement initiation
- Movement planning
- Movement plan reconsideration
- Movement execution
The control of both the posture and the voluntary movement can be divided into which levels?
- Upper motor system
- Spinal/lower motor system
The spinal/lower motor system is modulated by…
The upper system
It is capable of independent work
Postural reflexes are composed of…
- Spinal (LMS) reflexes
- Upper/supraspinal (UMS) reflexes
Postural reflexes perform which tasks?
- Antigravitational support
- The stabilisation of the centre of mass
- Stabilise the relative position of body parts (controlled by vermis of cerebellum)
Which nuclei control postural reflexes?
In the brain stem:
- Nucl. ruber
- Nuclei of reticular formation
- Deiters nucleus
Deiter’s nucleus and nuclei of reticular formation increase activity of…
Motor sensors of the spinal cord
What is the effect of cutting the connection between nucl**. ruber and Deiter’s nucleus?
Disinhibition of the effects of Deiter’s nucleus
- Leads to a drastic increase in extensor tone in the whole body (Increase of alpha and gamma motor neuron activity)
- Known as Decerebration rigidity
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Give the symptoms of spinal shock
- Areflexia
- Hypotension
- Poikilothermia
- Irreversible loss of sensory & voluntary functions
Recovery from areflexia
Somatic restitution
Recovery from anaesthesia
Vegetative restitution
Give the reflex types in the UMS
- Tonic reflexes
- Supporting reflexes (Reflexes maintaining the upright position)
- Statokinetic reflexes
- Placing & hopping reflexes
Tonic reflexes
Stabilisation of centre of mass/maintain antigravitational posture
Deiter’s nucleus receives inhibitory afferentation from…
- Cerebellum
- Cortex
- Nucl. ruber
Give the typical example of supporting reflexes
Cat being dropped whilst upside-down, landing on its feet
Give the steps of the cat supporting reflex example
- Turning back of the head (by labyrinth-eye-muscle reflex)
- Head in the normal position
- Stimulation of the receptors of the neck
- Turning of the neck and back
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Statokinetic reflexes
Positional reflexes evoked by movement stimuli
Accomplished by the integration of the eye, labyrinth and otolith organ
E.g: ‘Gimble’ effect of a chicken’s head when the body is moved
Placing and hopping reflexes
At the moment of arriving at the ground, extremities always move into the optimal position
- Uses a series of posture reflexes
The vestibular nucleus is innervated by…
Pseudounipolar sensory neurons of Scarpa’s ganglion
The most important efferentations of Scarpa’s ganglion
- Oculomotor nuclei
- Cerebellum
- Reticular formation
- Alpha & gamma motor neurons of the spinal cord
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During intentional movement, which afferents play the main role?
- Those that directly innervate the motor cortex
- Originating from the thalamus and sensory cortex
What are the most important movement initiative areas of the brain?
- Limbic system
- Orbital cortex
- Hypothalamus
- System of basal ganglia
Brodmann area 6 is known as the…?
Pre-motor area
Brodmann area 4 is responsible for…?
Final execution of movement
Give the order of processes in the motor cortex
- Supplementary: Movement intention
- Pre-motor: Sequence of movements
- Primary motor: Execution
- Movement
Give the different areas of the motor cortex
- Primary motor cortex
- Brodmann 6:
- Pre-motor area
- Supplementary area
Half of the pyramidal tracts originate from the…
Primary motor cortex
Pre-motor cortex function
- Determines the sequence of movements following each other
- Investigation nd determination of movement order
Motor pathways originate from…
- Pyramidal tract
- Extrapyramidal system
Axons from the pyramidal tract leave the neocortex as…
Corticospinal & Bulbospinal tracts
Transection of the pyramidal tracts at one side results in…
Paralysis of muscles on the opposite side
Informed movements are afferented from the cortex to the…
- Basal ganglia
- Cerebellum
Function of the basal ganglia and cerebellum
- Compare the existing movement patterns within a plan
- Send them back to the cortex in a modified form
The sensory function of the thalamus continuously provides the cortex with…
Excitatory impulses
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If the activity of an inner regulatory circuit increases…
The basic inhibitory tone is enhanced significantly
The loop causing this is maintained by an increase in excitatory tone
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Parkinson’s disease is caused by
The substantia nigra contains a vast number of dopaminergic neurons
- These affect the thalamus activating/inhibiting loops
The cerebellum is the organ of…
- Movement coordination
- Movement learning
- Attention
- Language
- Accurate timing
Give the main functions of the cerebellum
- Correction and refinement of the movement plan
- Learning and storing complex movement plans
Give the parts of the cerebellum
- Archicerebellum
- Paleocerebellum
- Neocerebellujm
The afferentation of the cerebellum is integrated by…
Purkinje cells
- Although no direct connection to the spinal cord
Afferents arrive at the cerebellum from which locations?
- Vestibular apparatus
- Collaterals of the visual pathway
The main role of the vestibulocerebellum
- Eye movement
- Balance of the body
Give the efferentation of the vestibulocerebellum
- Alpha + Gamma neurons of spinal cord
- Nucleus fastigii
- Then to:
- Deiters nucleus
- Reticular formation
- Nucleus ruber
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Spinocerebellum is composed of…
- Spinocerebellar tracts
- Paleocerebellum
The main function of the spinocerebellum
Finely adjust the strength of the muscle according to the actual status
In the spinocerebellum, the original movement plan is modulated through which loops?
- Thalamus-motor cortex-spinal cord loop
- Nucleus ruber-spinal cord loops
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Give the afferentations of the cerebrocerebellum
- Brodmann 4
- Brodmann 6
- Gyris postcentralis
The afferentations of the cerebrocerebellum switch in the pons allowing…
Comparison of:
- The cortical movement plan
- Cerebellar movement pattern
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Give the efferentation of the cerebrocerebellum
- Dentate nucleus
- Nucleus ruber
- Thalamus
- Motor cortex loop
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Function of the cerebrocerebellum
- Movement planning
- Timing of movements
Give the most important cell types in the cerebellar module
- Inhibitory cells
- Facilitating cells
Title the figure
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The cerebellar module
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Deep cerebellar nuclei
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Purkinje cell
Function of the basal activity of the Purkinje cell
Inhibition of the firing of deep nuclei
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Releasing deep cerebellar nuclei from Purkinje inhibition can lead to…
Increased main discharge frequency of the afferents originating here
Decreasing the activity of the Purkinje cell leads to…
Disinhibition - facilitation of the deep nuclei
The main efferentation centre of the cerebellum
Area of cerebellar deep nuclei:
- Nucl. fastigii
- Interpositus nuclei
- Dentate nucleus
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- Climbing fibre
- Mossy fibre
In the cerebellar module, an increase in the activity of granular cells leads to…
Activation of Purkinje cells in parallel with the inhibition of the Purkinje cells of the neighbouring zone
Consequences of removal of the cerebellum
Loss of refined coordinated movements
- Ataxia: Poor coordination
- Hypotonia
- Dysmetria
- Tremor
During sleep, … predominance is found
Parasympathetic
Give the phases of sleep
- SWS (Slow-wave sleep)
- REM/Paradoxical sleep
Sleep is measured with which equipment?
Electroencephalography (EEG)
REM accounts for …% of total sleep time
20-25%
Which figure shows the sleep cycles
A hypnogram
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Give the graph showing physiological changes during the phases of sleep
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Give the EEG waves seen during sleep stages
- Stage 1: Theta waves
- Stage 2: Sleep spindles and K-complexes
- Deep sleep: Delta waves
- REM sleep: Sawtooth waves
Title and annotate the figure
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Features of an early night sleep cycle
- NREM reaches its greatest depth at stage III and IV
Title and annotate the figure
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Late-night cycle
- NREM descends only to stage III
During sleep, the mean activity of the cortex…
Is not significantly decreased
Slow wave sleep is seen in phase numbers…
3 and 4
As well as reticular formation, sleep-wake cycles are also determined by the…
Suprachiasmatic nucleus
Suprachiasmatic nucleus (SCN) function
- Receives external stimuli by vision
- Biological clock - 24 hour circadian rhythms
Circadian rhythms are adjusted by…
Zeitgebers (such as daylight)
SCN is located in the…
Hypothalamus
How is sleep generated?
Serotonin facilitating synchronisation
What causes the shift to the REM phase?
Locus coeruleus produces norepinephrine
The reticular formation is formed by which Afferents?
- Viscerosomatic sensory system
- Afferent cranial nerves
- Sensory cortex
- Motor cortex
- Thalamus
- Hypothalamus
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The reticular formation is formed by which efferents?
- Descending reticular formation (reticulospinal tract)
- Efferents to the upper brain areas
- Thalamus
- Cortex
- Limbic system
- Cerebellum
- Hypothalamus
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Functions of the descending reticular system
- Inhibition of myotatic reflexes
- Increases intensity of the motor processes
Function of the ascending reticular system
Gears up the activity of all the upper centres
Title the figure
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The norepinephrine system
Title the figure
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Serotonin (5-HT) system
Title the figure
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Dopamine system
Title the figure
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The histamine system
Title the figure
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The cholinergic system
The limbic system supports which functions?
-
Integration of primitive cortical mechanisms:
- Emotional, sexual and visceral function
- Adrenaline flow
- Emotion
- Behaviour
- Motivation
- Long-term memory
- Olfaction
The limbic system is divided into…
- Medial limbic ring
- Amygdalic/basolateral limbic ring
The two main afferents of the limbic system
- Spinothalamic tract
- Olfactory tract
Give the main efferent of the limbic system
Pepez-circuit
The papez-circuit has efferent fibres to…
- Hypothalamus
- Thalamus + tectal nuclei
- Cingulate gyrus
Why is the pepez-_circuit_ named as such?
The efferent fibres reach the limbic system again
Mesopallium function
- Stimulation of amygdala - Attacking reaction
- Extirpation of the amygdala - Tame behaviour
- Septal nuclei - Evokes fear
Archipallium function
- Learning + Control of cortical memory processing
- Emotional reactions
Give the types of behavioural pattern group
- Ordinary
- Signalling
- Exploratory
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Give the three basic forms of instinctive behaviour
- Reflexes
- Taxes - Orientation instincts
- Modal series of action - Defence, attack, mating
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Instinctive behavioural patterns are evoked by…
Releasers
Motor response to a stimulus can either be…
Hereditary or acquired
-Pavlov
Unconditioned reflex example
Saliva production when meat is placed in a dogs mouth
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Define an unconditioned reflex
Congenital motor or secretory responses to external stimuli
Conditional reflex
Neutral stimulus becomes connected to the unconditioned stimulus
- Evoking the same reflex as the unconditioned stimulus
- E.g the bell in Pavlov’s experiments
Positive/negative reinforcement
To build up a conditional reflex of pleasant/unpleasant stimuli
If the reinforcement is not caused by the experimenter but by the animal, it is known as…
Operant reflex
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Increase behaviour
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- Remove noxious stimuli following correct behaviour
- Pressing the snooze button on an alarm clock
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- Behaviour avoids noxious stimulus
- Studying to avoid a bad grade
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Decrease behaviour
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- Add noxious stimuli following behaviour
- Spanking a child for swearing
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- Remove appetitive stimulus following a behaviour
- Telling a child to go to his room for cursing
What are the three main stages of memory formation and retrieval?
- Encoding
- Storage
- Retrieval, recall and recollection
Procedural memory
The memory of performance of an action
- Residing below the level of conscious awareness
Declarative memory
Memories that can be consciously recalled, such as facts and knowledge
Divided into:
- Episodic memory
- Semantic memory
Short-term memory
- Reverberation circuits
- Linked with the frontal lobe and association cortex
Middle-term memory
- Memory store for hours/days and longer
- Hippocampus, amygdala - Emotions and vegetative functions
- LTP - long-term potentiation
Long-term memory
- Not associated with one anatomical structure
- ‘Whole association cortex’
- Engrams: Morphological changes caused by repeated stimuli
During habituation experimentation with a gastropod’s syphon, Ca2+ open as well as…
Ca2+-activated inhibitory K+ channels
After repeated touching of the gastropod syphon, a gentle touch on the syphon results in…
Strong retraction of the gill
- Caused by the serotonergic axon terminating the syphon afferent
The gill muscle motorneuron is constantly stimulated by…
The syphon afferent
NMDA glutamate receptors can only be stimulated by…
- Significant depolarisation
- Transmission of a large amount of glutamate
In the hippocampus: A single/less intensive stimulation results in…
The opening of the non-NMDA glutamate receptor
- Therefore only a short-term AP transmission occurs
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In the hippocampus: A long-lasting stimulation causes…
- Prolonged depolarisation
- Releasing NMDA-linked cation (Na+ and Ca2+)
- Evokes a long-lasting Ca2+ signal
- Generation of retrograde signals
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