Neuro Lecture notes Flashcards
What are the general functions of the left hemisphere?
Verbal, linguistic description, mathematical, sequential, analytical and direct link to conscious mind
What are the general functions of the right hemisphere?
Almost non-verbal, musical, geometrical, spatial comprehension, temporal synthesis, possible link to conscious mind
What are the four lobes of the brain?
Frontal
Temporal
Parietal
Occipital
What is the central sulcus?
A division between the frontal and parietal lobe
What is the lateral sulcus?
A division between the temporal and the frontal&parietal.
What are the clinical signs of UMN lesion?
No change in aspect
Increased tone- spasticity
Pyramidal weakness
Increased reflexes
What are the clinical signs of LMN lesion?
Muscular atrophy
Decreased tone
Focal weakness
What are the four ventricles?
A pair of lateral ventricles
III
IV
What are the cranial nerves?
Olfactory Tract Optic Occulomotor Trochlear Trigeminal Abducens Facial Vestibulochlear Glossopharyngeal Vagus Accessory Hypoglossal
What are the arteries feeding into the Circle of Willis?
The internal carotid artery- a branch of the common carotid artery
The vertebral arteries
What are the main branches of the Circle of Willis?
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
What do the vertebral arteries merge to form?
The basilar artery
What percentage of the brain is water?
80%
What are the principles of dualism?
There are 2 kinds of “foundation”- mental and body
The mental cannot exist without the body; and the mind cannot think
What is reductive physicalism?
Everything is applicable to the physical
What is interactionism?
Entities have an effect on one another
What is epiphenomenalism?
Physical affects mental but mental can’t effect physical
What is mysterism?
Mind is only understood by reflection
Why does the biomedical model predominate?
Power, economics, convenient, familiar, reductionism
What is neurology?
Looking for abnormal brain chemistry, genetics, perfusion, structure
What is psychiatry?
The functional consequences of distress and interaction with environment, interpersonal, psychological, social and cultural issues
What are the functions of the dopamine pathways?
Reward, pleasure, motor function, compulsion, preservation
What are the functions of the serotonin pathways?
Mood, memory processing, sleep, cognition
Name 3 tests of executive function
Wisconsin card-sorting test
Proverb interpretation
Similarities test
How common is schizophrenia?
Affects roughly 1 in 100
What are the positive symptoms of schizophrenia?
Delusions, thought disorder, hallucinations
What are the negative symptoms of schizophrenia?
Withdrawal, can’t carry on normal activities
What are the biological correlations of schizophrenia?
Brain Volume
Functional imaging
Dopamine theory
Genetic factors
What are the non-biological correlations of schizophrenia?
Urbanicity
Childhood trauma
Stress
Why may it be good to classify a mental disorder?
Public health issues e.g. allocation of resources Facilitates meaningful communication Feeling of being understood Framework for research Treatment and prognosis
Why may it be bad to classify a mental disorder?
Arbatory thresholds
Stigma and prejudice
Over simplification and reductionism
What are the two divisions of the vertebrate nervous system?
- CNS= within the skull and spine
- PNS= Outside the skull and spine
What is the difference between the somatic and automatic nervous system?
The somatic is the part that interacts with the external environment, the automatic is the part that regulates the bodies internal environment: organs
What type of sensory input is received by the spinal cord?
Nervous or contact stimuli
What type of sensory input is received by the hind brain?
Sudden distal stimuli
What type of sensory input is received by the midbrain and hypothalamus?
Species specific threat stimuli
What type of sensory input is received by the thalamus?
Neural stimuli
What type of sensory input is received by the sensory cortex?
Complex neural stimuli
What type of sensory input is received by the hippocampus and septum?
Context
What type of sensory input is recieved by the frontal cortex?
Cognitive analysis
What type of output is produced by the frontal cortex?
Response supression
What type of output is produced by the amygdala?
Conditioned, emotional response
What type of output is produced by the midbrain and hypothalamus?
Species-specific response
What type of output is produced by the hind brain?
“Startle” response
What type of output is produced by the spinal cord?
Reflexive withdrawal
Is the dorsal root afferent or efferent?
Afferent
Is the ventral root afferent or efferent?
Efferent
What is the role of the medulla?
Low level sensorimotor control
Same with vital functions, sleep, motor
What is the role of the pons?
Relay from cortex and midbrain to cerebellum
What is the role of the cerebellum?
Co-ordinates movement and balance. Mainly fine coordinated voluntary movement
What is the difference between the superior colliculus and inferior colliculus?
The superior is sensitive to sensory change- orienting/defence movements
The inferior is similar but for auditory events
What are the three components to the tegmentum?
The periaquidal gray
The red nucleus
The substantia Nigra
What are the roles of the periaquiductal gray?
Role in defence, pain and reproduction
What are the roles of the red nucleus?
Target of cortex and cerebellum, project to spinal cord. Role in pre cortical motor control
What are the roles of the specific nuclei within the thalamus?
Relay signals to the cortex/limbic system for all sensations (Exc smell)
What are the roles of the non-specific nuclei within the thalamus?
Role in regulating state of sleep, wakefullness, and levels of arousal. Important relays from basal ganglia and cerebellum back to cortex
What is the role of the hypothalamus?
Regulates pituitary and role in hormonal role of motivated behaviour- co-ordinates drive related behaviour
What are the structures contained within the limbic system?
Amygdala Mammillary body Hippocampus Septum Cingulate Gyrus Fornix
What is the role of the amygdala?
Associating sensory stimuli with emotion. Responsible for fear.
What is the role of the mammillary body?
Formation of recollective memory
What is the role of the hippocampus?
Long term and spatial memory. Critical for episodic memory. Essential for the construction of mental images. Has a vital role in short term memory.
What is the role of the septum?
Defense and aggression
What is the role of the cingulate gyrus?
Linking behavioural outcomes to motivation
What is the role of the fornix?
Carrying signals from the hippocampus to mammillary bodies and septal nucleus
What is the role of the precentral gyrus?
Motor instructions
What is the role of the primary motor cortex?
Contains many cells giving origin to the descending motor pathways
What is the role of the premotor and supplementary motor areas?
Higher level motor plans and initiation of voluntary movements?
Where are the precentral gyrus, primary motor cortex, premotor and supplemetary motor areas?
Within the frontal lobe
Where is the post-central gyrus and primary somatosensory cortex?
Within the parietal lobe
What is the role of the primary somatosensory cortex?
Body and head’s position in space
Permits complicated spacio-temporal predictions
Where are the primary auditory complex and inferotemporal cortex found?
Within the temporal lobe
What is the role of the inferotemporal cortex?
Recognition of faces and objects
Where is the visual corticies?
Within the occipital lobe
What is the dorsal stream?
Vision for movement
What is the ventral stream?
Vision for identification
What are the levels of description within the research of neuroscience?
Psychological Systems Microcircuit Neuronal Intracellular Molecular
What are some of the possible constraints of research within neuroscience?
Expertise, facilities, time, money, ethics
What is a contrast X-ray?
An x-ray, but using an injected substance. This provides image contrast between intravascular and extravascular components
What are the different techniques that can be used successfully on humans within neuroscience?
Contrast X-ray MRI fMRI PET EEG MEG TMS&TDCS
What are the different invasive methods that can be used in animal models of neuroscience research?
Direct measurement of brain activity
Determining connectivity between structures
Distrupting connectivity between structures to determine effects on circuit function
Leison specific structures to inform us about its function
Pharmacological research
Genetic manipulations
Optogenetics
What is fMRI?
Altered MRI to be sensitive to oxygenated or deoxygenated blood. Blood changes due to brain activity.
How can PET scan be used in neuroscience?
Use a contrast agent that is specific to a biological process. The chemical will bind to the target. Attach a radioisotope to a positron emitter. Inject the tracer then image. Poor spatial and temporal resolution.
How can an EEG be used in neuroscience?
Using electrodes on scalp, can analyse regional brain activity. Good temporal resolution and bad spatial resolution. Analysis is complex. Can be used to look at brains response to stimuli.
When are neurons formed?
Mainly, but not exclusively, formed during brain development
What are the two types of synapse? Which is more common?
Chemical- majority
Electrical- Less abundant
Briefly describe how a synapse works
Nerve travels down axon, causing depolarisation. This opens voltage-gated Ca2+. Neurotransmitter is released into synaptic cleft and attaches to receptor on the post synaptic membrane.
What is the importance of neural plasticity?
It is the basis of learning and memory
What can change between neurons? (heterogeneity)
Size
Morphology
Electrical properties
Neurotransmitters
What is the difference between upper motor neurons and striatal interneurons?
Upper motor neurons- large, excitatory, glutametergic, long projection pyramidal cells.
Striatal interneuron- small, inhibatory, GABAergic
Describe olgiodendrocytes
Myelinating cells of the CNS
Unique to vertebrates
Myelin insulates axon segments, enables rapid nerve conduction
Myelin sheath segments interrupted by nodes of ranvier- saltatory conduction
Provides metabolic support for axons
What is the myelin sheath?
Formed by wrapping of axons by olgiodendrocyte processes. Highly compacted- 70% lipid, 30% protein.
Myelin specific proteins e.g. MBP, involved in compaction.
Describe microglia
Resident immune cells of the CNS. Originate from yolk sac progenitors that migrate into CNS
“Resting” state- highly ramified, motile processes that survey the environment. Upon activation, they retract their processes, becoming “ameoboid” and motile. Proliferate at sites of injury- phagocytic.
What are the functions of microglia?
Immune surveillance
Phagocytosis- debris/microbes
Synaptic plasticity- pruning
What are astrocytes?
Star-like cells. Most numerous glial cells in the CNS. Highly heterogenous. Common “marker” glial fibrillary acidic protein.
What are the functions of astrocytes?
Developmental Structural- define brain architecture Envelope synapses Homeostatic- buffer K+, glutamate etc Metabolic support Disease- gliosis/astrocytosis Neurovascular coupling
What are the features of the blood-brain barrier?
Endothelial tight junctions Astrocyte end feet Pericytes Lacks fenestrations Specific transporters
What is the choroid plexus formed from?
Modified ependymal cells
What is the main site of CSF production?
The choroid plexus, mainly within the lateral ventricles
What are the functions of the frontal lobe?
Voluntary movement on opposite side of body
Frontal lobe of dominant area controls speech (Brocas area) and writing
Intellectual functioning, thought processes, reasoning and memory
What are the functions of the parietal lobe?
Recieves and interprets sensations, including pain, touch, pressure, size and shape, and body-part awareness
What are the functions of the temporal lobe?
Understanding the spoken word, sounds as well as memory and emotion
What are the functions of the occipital lobe?
Understanding visual images and meaning of written words
How does a neuron stain under H&E?
The haemotoxylin stains the nucleic acids blue, and the eosin stains the proteins red
What are the basic components of neurons?
Dendrites
Cell body/Soma
Axon
Presynaptic terminals
What are the symptoms of multiple sclerosis?
Eye movements are controlled Slurred speech Paralysis Tremor Loss of co-ordination Sensory weakness
What is diffusion?
The force driving molecules to move to areas of lower concentration
What is the ratio of sodium ions to potassium ions pumped by the sodium-potassium pump?
Three sodium ions for every two potassium ions
What is temporal summation?
One axon firing many times
What is spatial summation?
Lots of axons firing once
What are the symptoms of novichok poisoning?
Muscle convulsions Paralysis Heart Failure Asphyxiation Constricted Pupils Vomiting
What are the five fundamental processes of synaptic transmission?
- Manufacture
- Storage
- Release
- Receptor activation
- Inactivation
How long do fast neurotransmitters last and give some examples
Short lasting
Acetyl choline, glutamate, gamma-aminobutyric acid
How long do slow neurotransmitters last and give some examples
Slow acting
Dopamine, Noradrenaline, Serotonin
What chemicals affect ACh?
Cigarettes
Poison Arrows
Spider Toxins
Nerve gas
What chemicals affect Noradrenaline?
Antidepressants (imipramine blocks reuptake)
Antidepressants (MAO inhibitors block break-down)
Stimulants
What chemicals affect dopamine?
Antipsychotic drugs
Stimulants
Antiparkinsons drugs
What chemicals affect serotonin?
Antidepressant drugs
Hallucinogens
Ecstacy
What are the side effects of GABA?
Anti anxiety
Anti convulsant
Anaesthetic
What are the side affects of L-DOPA?
Anti-psychotic
Causes Parkinsons symptoms at high doses
Why may CT Scans be used instead of MRI scans to analyse the brain?
Better for bone and calcification
Quicker scan times than MRI
MRI can be noisy and claustrophobic
Why may MRI scans be used instead of CT scans to analyse the brain?
CT scans require ionated contrast media= allergic reaction? (MRI do not)
CT scans use a high dose of X-rays
MRI provides excellent anatomical detail
What are the two muscles that control lid position?
Orbicularis oculi (Closes lid, controlled by CN VII- facial) Levator palpebrae muscle (elevates upper lid, sympathetic nervous supply)
Where are the meibomian glands and why are they important?
There is a series of openings on the lid. The glands themselves lie in the tarsal plate. They secrete the early components of the tear film
What is the function of the conjunctiva?
Acts as a barrier
Produces mucin from the goblet cells and aqueous part of tear film from the accessory lacrimal glands
What are the layers of the tear film and roles of each?
Anterior lipid layer- stabilizes tear film and reduces evaporation
Middle aqueous layer- Contain antibodies, enzymes and vitamin C
Deep mucin layer- Allows aqueous layer to spread over relatively hydrophobic cornea apithelial cells
What are the general functions of the tear film?
Protects
Provides smooth, clear, anterior refracting surface for cornea
Where are tears produced and what is their function?
Produced by main lacrimal gland in response to stimuli
Acts as a protective agent when the eye is irritated and helps wash out foreign bodies
What is the nervous supply to the cornea?
Opthalmic divison of the trigeminal nerve (CN V)
What are the layers of the cornea?
Epithelium (anterior)
Stroma (Middle)
Endothelium (Posterior)
Describe the stroma of the cornea
Regular lamina of collagen fibres, dehydrated, no blood vessels, thickest part
What is the function of the fluid pump in the endothelium of the cornea?
To counteract the tendancy of the cornea to become cloudy
Where does the cornea receive nutrients from?
No vessels (transparent) so receives nutrients from the tear film anteriorly and aqueous humour posteriorly
What is the site of the trabecular meshwork?
The anterior chamber angle
What are the muscles of the iris and their nervous supply?
Dilator muscle (sympathetic branch of nerves to eye, has alpha receptors) Sphincter muscles (parasympathetic fibres within CN III, contains muscularinic receptors)
What is the function of the iris?
To control light entry
What is the function of the lens?
To focus light onto the retina. Also can alter shape thus increasing or decreasing the refracting power of the eye
What is the function of the ciliary body?
Pars plicata: ciliary processes that secrete aqueous humour. Enhanced by folds to increase SA
Pars plana: Thin part which merges with choroid
What is the innervation of the ciliary muscle?
Parasympathetic fibres in CN III
Where is the vitreous humour found?
Between the posterior lens and retina
What does the vitreous humour consist of?
A scaffold of collagen fibres and large, negatively charged molecules.
What is the retina made up of?
Outer layer photoreceptors
1st and 2nd order neurons (bipolar and ganglion cells)
Interneurons (amacrine and horizontal cells)
Neuroglial cells
Pigment cells
Supporting membranes
What tools would be used to view the surface of the retina?
An opthalmoscope
Describe the macula
3mm Central area temporal to optic disc
Thickest part of retina
Highest concentrations of cones
Yellowish pigment
Describe the fovea
Central zone of macula (concave profile) Thinnest part of retina Just consists of cones No retinal blood vessels Best visual acuity
What is the role of the choroid?
Removes heat from retina
What is the diameter of the optic disc?
1.5mm
What is the general colour of the optic disc and why?
Pink as there are lots of capillaries
Where is the blind spot?
In the optic disc
What is the sclera?
Tough, protective outer layer of globe. Perforated posteriorly by optic nerve. Openings for vessels. Irregularly arranged collagen fibres for strength. Covered in a thin, vascular episclera
What causes the pupil diametre to change?
- Changes in light intensity
- Proximity of object
- State of arousal
What are the causes of abnormal light response?
Afferent= Optic nerve disease, severe retinal disease Efferent= Third nerve palsy, adie pupil, damage to iris, atropine
What is the dark response?
Active dilation by sympathetic stimulation of dilator muscle as well as inhibition of sphincter muscle
What is the ciliospinal reflex?
Painful stimulation of neck causes pupil dilation on the same side
Why is there a high intraocular pressure?
To allow the eye to move without deforming
What tool is used to measure intraocular pressure?
Tonometer
What is glaucoma and hypotony?
Glaucoma- high intraocular pressure
Hypotony- Low intracular pressure
What are the branches of the opthalmic artery and what do they supply?
Central retinal artery- inner retina
Ciliary arteries- outer retina and anterior part of globe
Additional Branches
Are the retinal capillaries or choroidal capillaries leaky?
Choroidal
What are the two visual systems of each eye?
Scotopic (monochromatic, low light conditions, function of rods)
Photopic (chromatic, bright light conditions, function of cones)
What is the trichromatic colour theory?
There are three types of cones and they respond differently to wavelengths of light. The maximum response roughly matches red, green and blue light. Different cones response to different wavelengths are perceived as colour.
What factors limit visual fields?
Extent of retinal photoreceptors
Facial anatomy
What are the dimensions of the visual fields?
Nasally 60 degrees
Temporally 100 degrees
Superiorly 70 degrees
Inferiorly 80 degrees
What is myopia and hyperopia?
Myopia- the eye is too long, short sightedness
Hyperopia- The eye is too short, long sightedness
What happens when images are brought closer to the eye?
Near reflex
- The lens increases its refracting power
- The eyes converge
- The pupils constrict
What tool is used to measure visual acuity?
The snellen chart
What is a strabismus?
A squint
What are the clinical features of a retinal problem?
- Total loss of vision in one eye
- Loss of part of visual field in one eye that mirrors area damage
- Loss of the upper or lower half of field of vision
- Loss of centre of vision; central scotoma
- Tunnel vision
What are the clinical features of an optic nerve problem?
- Enlarged blind spot
- Loss of centre of vision
- Loss of vision in arc shape
- Tunnel vision
What are the clinical features of an optic chiasm problem?
-Loss of temporal field of vision in both eyes; bitemporal hemianopia
What are the clinical features of an optic tract problem?
- Loss of field of vision on the contralateral side to the side of the problem. Problem is homonymous (temporal in one eye and nasal in other), affecting up to 1/2 of the visual field and greater in one eye than the other
What are the clinical features of an optic radiation problem?
- Contralateral homonymous field defects that are either predominantly in the inferior visual field (parietal lobe lesion), or the superior visual field (temporal lobe lesion). The effects are similar in both eyes.
What are the clinical features of a visual cortex problem?
- Highly congruous, contralateral, homonymous hemianopia
- As they are often vascular and the occipital lobe has a blood supply from the middle and posterior cerebral arteries, the central visual field is often spared.
In what order should one clinically examine the eye muscles?
- Lateral and medial rectus
- Superior and inferior rectus
- Inferior and superior oblique
How should you examine lateral and medial rectus?
Sit in front of the patient. Place a finger at eye level, at about an arms length from their face and move it right to left. Observe each eye in turn.
How should you examine superior and inferior rectus?
Sit in front of the patient. Get the patient to look 23 degrees to the side. Place a finger about an arms length from their face and move it up and down. Observe each eye in turn.
How should you examine inferior and superior oblique?
Sit in front of the patient. Place a finger at eye level at about an arms length from their face and out to the side. Move the finger up and down. Repeat on both sides.
What are the three semi-circular canals?
Anterior, posterior and lateral
Why does dizziness occur?
When the semi-circular canals send signals to the brain when there is no movement.
Physiological cause= after spinning
Pathological cause= Labarynthitis
Describe the vestibulo-ocular reflex test
Lie patient on side
Poor ice-cold water in the ear. This creates a convection current in the canal.
This sends a signal to the brian
The eyes should slowly move towards the cold water, then jump back to normal position.
Define sensation
The mental process that results from the immediate external stimulation
Define perception
The ability to become aware of something, or understand something following sensory stimulation
What are the 5 types of perception?
Tactile, gustatory, visual, auditory, olfactory
What is the perceptual set?
The psychological factors that determine how you perceive your environment. Context Culture Expectations Mood and motivation
What is bottom up processing and top down processing?
Broadly speaking, bottom up processing is sensation, and top down processing is perception
What is a hallucination?
Experiences involving the apparent perception of something not present.
An error in top down processing. They are unique in individuals due to their different perceptual set.
What is the normal human hearing range?
20 Hz- 20 KHz
Describe the Pinna
A cartilaginous structure. It is formed from pharyngeal arches 1 and 2 (6x hillocks of his).
What is the role of the outer ear?
Direct sound waves towards the ear canal.
How much of the outer ear canal is cartilage and how much is bone?
1/3 cartilage, 2/3 bone
What is the pars flaccida and pars tensa?
The pars flaccida is the top 1/3 of the tympanic membrane
The pars tensa is the bottom 1/3 of the tympanic membrane
What muscles are within the middle ear, and what bone are they attached to?
Tensor Tympani (malleus) Stapedius (Stapes)
What is the role of the middle ear?
To amplify air-bone sound vibration
What are the roles of the middle ear muscles?
Protection of inner ear from acoustic trauma
Stiffens the ossicular chain
Stapedius is stimulated acoustically
25 ms reaction time in man
Tensor tympany- Voluntary and involuntary control
Chewing
What are the roles of the eustachian tube?
Ventilation of the middle ear space, keeping pressure equal
Drainage of secretions
Describe the inner ear
A set of fluid filled sacs, encased in bone
Innervated by the vestibulocochlear nerve
What is the role of the labyrinth?
Balance
How many spirals are formed in the cochlear?
2.7
What are the two openings of the cochlear?
Round window and oval window
What are the three compartments of the cochlear?
Salca tympani
Salca media
Salca vestibuli
What are the endolymph and perilymph? Where are they found?
Endolymph- High K+ solution , found in scala media
Perilymph- like ECF and CSF, Na+ rich, found in Scala tympani and scala vestibuli
What is the difference between the basilar membrane base and apex?
The base (tympanic membrane) is narrow and stiff. It detects high frequencies. The apex is wide and floppy. It detects low frequencies.
What are the roles of the inner and outer hair cells?
Inner= mechanical transducens Outer= Fine tuning
How does movement of the stereocilia cause release of neurotransmitter?
Movement of sterocilia
Rapid response required
Mechanically gated K+ channels are opened, causing depolarization
This results in opening of voltage-gated Ca2+ channels
Release of neurotransmitter
What are the parts of the central auditory pathway? (ECOLI)
Eighth nerve Cochlea Olive Lateral lemniscus Inferior colliculus
What is conductive hearing loss?
A defective outer or middle ear
What is sensorineural hearing loss?
A defective inner ear
What are the latin names of the midbrain, forebrain and hindbrain?
Forebrain- Prosencephalon
Midbrain- Mesencephalon
Hindbrain- Rhombencephalon
What are the parts of the prosencephalon?
Telencephalon (hemispheres and basal ganglia)
Diencephalon (thalamus, subthalamus, hypothalamus, epithalamus)
Define psychological stress
The state of mental or emotional strain or tension resulting from adverse or demanding circumstances
What is eustress?
Positive stress which is beneficial and motivating. Typically the experience of striving for a goal which is within reach,
What is distress?
Negative stress which is damaging and harmful. Typically when a challenge is not resolved by coping or adaptation.
What is acute stress?
Short lived response to a novel situation experienced by the body as a danger.
What is chronic stress?
Arises from repeated or continued exposure to threatening or dangerous situation, especially those that cannot be controlled.
What are some causes of chronic stress?
Physical illness Physical or sexual abuse Poverty Unemployment Bullying Caregiving
What are the 3 phases of Selye’s syndrome?
Alarm- Threat is realised
Adaptation- Body engages defense response
Exhaustion- Body runs out of defensive responses
What are the five elements of the human stress response?
Biochemical Physiological Behavioural Cognitive Emotional
Describe the sympathomedullary path of the stress response
Hypothalamus activates adrenal medulla
Adrenal medulla releases adrenaline and noradrenaline into bloodstream
Body prepares for fight or flight. Adrenaline and noradrenaline reinforces the pattern of sympathetic activation
Energy
Describe the pituitary-adrenal system of the stress response
Higher brain centre activates hypothalamus
Hypothalamus releases corticotrophin
Pituitary gland releases adrenocorticotrophic
Adrenal cortex releases corticosteroids
Corticosteroids causes changes- liver releases energy and immune system is suppressed
What is the biochemical stress respose?
Glucocorticoids (Cortisol)
Catecholamines (Adrenaline and noradrenaline)
Inflammation and immune response
What are the immediate physiological stress responses?
Rapid breathing Increased blood flow Increase HR and BP Tense muscles Glucose release RBC discharged from spleen Dry mouth Sweating
What are the later physiological stress responses?
Headache Chest pain Stomach ache Low energy Loss of labido Colds and infections
What are the behavioural stress responses?
Easily startled Change in appetite Change in weight Procrastination or avoiding responsibilities Alcohol, drugs Nail biting, fidgeting Sleep disturbances Withdrawal
What are the cognitive stress responses?
Worrying Racing thoughts Forgetfulness Inability to focus Poor judgement Pessimistic Learning
What are the emotional stress responses?
Depression and sadness Tearfulness Mood swings Irritibility Restlessness Aggression Low self-esteem Boredom Overwhelmed Rumination, anticipation and avoidance
What is allostasis?
It refers to how multiple and complex systems adapt collectively in changing environments through dynamic change
What are the symptoms of PTSD?
Vivid flashbacks and nightmares Sweating Nausea Trembling Hyper vigilance Insomnia Irritibility
Define natural selection
The differential survival and reproduction of individuals due to differences in phenotype
What is evolutionary medicine?
The application of modern evolutionary theory to understand health and disease. It considers a species perspective with related interests to evolutionary psychology and medicine.
What are tinbergen’s questions?
Mechanism- How does this behavior occur in an individual?
Development- How does this behavior arise in an individual
Evolution- How does this behavior arise in the species
Adaptive value- Why is this behaviour adaptive for the species
What is compassion focussed therapy?
Therapy rooting in evolutionary and neuroscience approach to physiological processes. CFT is aimed at facilitating development of soothing and social safeness system
What are the three types of retinal ganglion cells and what does each do?
Parvocellular- Low contrast, High linear spatial resolution layers 1 and 2
Konicocellular- Blue-yellow colour oppenency, layers 3 to 6
Magnocellular- High contrast, low resolution, motion detection, colour blind, interspersed
What does the brain use for analysing depth perception?
Familiar size Occlusion Linear perspective Size perspective Shadows and illumination Motion Parallax
What are the symptoms of a lesion affecting the middle temporal visual area?
Akinetopsia (loss of motion vision)
Impaired saccades
What are the three types of saccades?
Spontaneous
Reflexive
Voluntary
What is the function of a vestibular eye movement?
Holds eye steady on retina during brief head rotations or translations
What is the function of the visual fixation eye movements?
Holds the image of a stationary object on the fovea by minimising ocular drifts
What is the function of the optokinetic eye movement?
Holds images steady on the retina during sustained head rotation
What is the function of the smooth pursuit eye movement?
Holds the image of a small moving target on the fovea; or holds the image of a small near target on the retina during linear self-motion
What is the function of a nystagmus quick phase eye movement?
Reset the eyes during prolonged rotation and direct gaze towards the oncoming visual scene
What is the function of a saccade eye movement?
Bring images of objects of interest onto fovea
What is the function of a vergence eye movement?
Moves the eyes in opposite directions so that images of a single object are placed or held simultaneously on the fovea of each eye
Where do pyramidal motor pathways originate?
The cerebral cortex
Briefly describe the difference between the lateral and anterior corticospinal tract
Lateral- crosses over at medulla, terminates at ventral horn synapsing with lower motor neurons. Carries limb information. Roughly 90% of pyramidal fibres are lateral
Anterior- Remains ipsilateral, terminates at ventral horn of cervical and upper thoracic segments. Carries info about axial muscles. Roughly 10% of pyramidal fibres.
Describe the corticobulbar pyramidal tract
Supplies musculature of the head and neck
Terminates at the brainstem on the motor nuclei of the cranial nerves
Lower motor neurons carry motor signals to muscles of face and neck
Where do extrapyramidal motor tracts originate?
The brain stem
What are the four extrapyamidal tracts and each of their actions?
Tectospinal- head turning in response to visual stimuli
Rubrospinal- Assists in motor function
Vestibulospinal- Muscle tone and posture
Reticulospinal- Spinal reflexes
What are the main differences between a UMN lesion and a LMN lesion?
UMN- No muscle wasting, hypertonia, paralysis affects movements of groups of muscles, hypereflexia, absent fasciculation, present babinski sign and clasp-knife reflex
LMN- Atrophy, hypotonia, flaccid paralysis, hyporeflexia, present fasciculation, absent babinski sign and clasp-knife reflex
What are the 12 cranial nerves?
Olfactory Optic Occulomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal
Which of the cranial nerves have parasympathetic innervations?
3, 7, 9, 10
Which cranial nerves have special sensory innervation?
Olfactory (smell) Optic (Vision) Facial (Taste to anterior 2/3 of tongue) Vestibulocochlear (Auditory) Glossopharyngeal (Taste to posterior 1/3 of tonuge) Vagus (Taste to epiglottis)
Where does each cranial nerve exit the skull?
1- Cribriform plate 2- Optic Canal 3- Superior orbital fissure 4- Superior orbital fissure 5- V1 - Superior orbital fissure V2- Foramen rotundum V3- Foramen Ovale 6- Superior orbital fissure 7- Internal acoustic meatus then stylomastoid foramen 8- Internal acoustic meatus 9- Jugular foramen 10- Jugular foramen 11- Jugular foramen 12- Hypoglossal canal
What are the tests for each cranial nerve?
1- Smell test
2- Snellen chart, Fundoscopy, cover aspects of eye
3,4,6- H eye test
5- Clench teeth, test face sensation
7- Inspect face for asymmetry during facial expression, taste test
8- Whisper number into patients ear
9- Taste test
10- Analyse patients voice, gag reflex test
11- Turn head against resistance, shrug shoulders
12- Protrude tongue, inspect for asymmetry
Cranial nerves: Is the optic nerve sensory function, motor function, or both?
2- Sensory (special sense of vision)
Cranial nerves: Is the opthalmic nerve sensory function, motor function, or both?
1- Sensory (special sense of smell)
Cranial nerves: Is the occulomotor nerve sensory function, motor function, or both?
3- Motor ( Movement of eye muscles)
Parasympathetic (pupillary reflex)
Cranial nerves: Is the trochlear nerve sensory function, motor function, or both?
4- Motor (Movement of superior oblique)
Cranial nerves: Is the trigeminal nerve sensory function, motor function, or both?
5- Sensory ( Face and mouth)
Motor (muscles of mastication by V3)
Cranial nerves: Is the abducens nerve sensory function, motor function, or both?
6- Motor (Movement of lateral rectus)
Cranial nerves: Is the facial nerve sensory function, motor function, or both?
7- Motor ( Muscles of facial expression and stapedius)
Parasympathetic (Lacrimal gland and submandibular/sublingual glands)
Special sensory (Taste to anterior 2/3 of tongue)
Cranial nerves: Is the vestibulocochlear nerve sensory function, motor function, or both?
8- Special sensory (Hearing and balance)
Cranial nerves: Is the glossopharyngeal nerve sensory function, motor function, or both?
9- Motor (Stylopharyngeus muscle)
Sensory (Skin of external ear, posterior 1/3 of tongue, carotid body, carotid sinus, eustachian tube)
Special sensory (Taste to posterior 1/3 of tongue)
Parasympathetic (Parotid gland)
Cranial nerves: Is the vagus nerve sensory function, motor function, or both?
10- Motor (Muscles of pharynx and larynx) Parasympathetic (Viscera of abdomen and thoracic wall) Sensory (external ear) Special sensory (Epiglottis)
Cranial nerves: Is the accessory nerve sensory function, motor function, or both?
11- Motor (Sternocleidomastoid, trapezius)
Cranial nerves: Is the hypoglossal nerve sensory function, motor function, or both?
12- Motor (Intrinsic and extrinsic muscles of the tongue)
Define pain
Unpleasent sensory and emotion associated with actual or potential tissue damage or described in terms of such damage
Define nociceptive pain
Actual or threatened damage to non-neural tissue and is due to activation of nociceptors
Define neuropathic pain
Pain caused by a lesion or disease of the somatosensory nervous system
Define allodynia
Pain due to a stimulus that does not normally provoke pain
Define dysethesia
An unpleasent abnormal sensation, can be spontaneous or provoked
Define hyperalgesia
Increased pain from a stimulus that normally provokes pain
What is the difference between acute and chronic pain?
Acute = less than 12 weeks
Chronic pain= Continuous pain for more than 12 weeks. Pain persisting beyond tissue healing time
What are the roles of the insular cortex?
Perception, motor control, self awareness, interpersonal experience
Plays a role in addiction
Degree of pain judged here
What are the causes of cancer pain?
- Pain directly from tumour
- Cancer therapy pain
- Pain unrelated to the cancer
Describe the pain pathway
- Initial injury activates nociceptors peripherally
- Nociceptors begin to fire (inflammatory soup)
- The impulse within the afferent neuron rapidly goes into the dorsal root ganglion
- Here, it projects into the 2nd order neuron which travels on the ipsilateral side into the spinolthalamic tract
- This travels up spinal cord to the thalamus and in the thalamus it projects another impulse into the sensory cortex
What are the symptoms of depression?
General- Low mood, anhedonia, low energy
Biological- Poor sleep, Poor appetite, Reduced labido, Poor concentration
Cognitive- Worthlessness, guilt, hopelessness, suicidal thoughts
Describe the HPA axis
- In response to stress, the hypothalamus causes release of corticotropin releasing hormone
- The anterior pituitary detects this and secretes anderrinotopic hormone
- The adrenal cortex thus releases cortisone, which acts as a negative feedback loop to inhibit the hypothalamus and anterior pituitary
How does the volume of the brain alter in depressed patients?
Large vol loss of dorsolateral prefrontal cortex
Reduced hippocampus size
What affect do antidepressants have on the brain?
Increased GR expression thus regulating HPA activity
Increased neurogenesis
Increased BDNF synthesis, increasing the number of synapses
What is the default mode network?
The resting state of the brain- daydreaming and internal flow of consciousness. Includes autobiographical details, self reference and thinking about others.
What is a motor unit?
A single alpha motor neuron and all the muscle fibres it innervates. Different motor neurons innervate different numbers of muscle fibres. Fewer fibres means greater movement resolution.
What is the motor pool?
All the lower motor neurons that innervate a single muscle. They contain both alpha and gamma motor neurons. They are of ten arranged in a rod-like shape within the ventral horn of the spinal column.
What are the two ways in which cell bodies in the ventral horn can be activated?
- Sensory information from the muscle
2. Descending information from the brain
Where is the golgi tendon organs and what do they detect?
They are located within the tendon. Mostly, it is sending sensory information to the brain via the spinal cord about the tension in the muscle/ the muscle’s force.
What is the innervation of intrafusal and extrafusal fibres?
Intrafusal- gamma motor neurons
Extrafusal- Alpha motor neurons
Where are muscle spindles and what do they detect?
They are embedded within most muscles and are composed of intrafusal fibres. They detect stretch regardless of current muscle length.
What are the role of sensory fibres within muscle spindle feedback?
They coil around intrafusal fibres and are innervated by gamma motor neurons. They keep the intrafusal fibres set at a length that optimises muscle strength detection.
What is the size principle?
Units are recruited in order of size. Fine control is typically required at lower forces.
What are the numbers of muscle fibre variants?
- Level of control
2. Strength
What are the three fibre types?
Slow
Fast fatigue resistant
Fast fatiguable
What is the output of the basal ganglia?
Mainly inhibitory information- travels to the cortex via the thalamus
What is centralised selection?
There are multiple command systems that are spatially distributed. They process in parallel and all act through a final common motor path. Centralised selection decides which pathway to choose. It inhibits all other pathways to allow the chosen pathway through. It is done by the basal ganglia.
What are the symptoms of cerebellar damage?
DANISH D- Dysdiodochokinesia A- Ataxia N- Nystagmus I- Intention Tremor S- Slurred speech H- Hypotonia
What is a commisure?
A tract connecting one hemisphere to the other
What is asynergia?
Loss of co-ordination of motor movement
What is nystagmus?
Abnormal eye movements
How many layers are there of neocortex?
6
What are the inputs/projections of each layer of neocortex?
1- No inputs/projections 2- Inputs from other cortical areas 3- Projects to other cortical areas 4- Input from thalamus 5- Project to brainstem and spinal cord 6- Projects to thalamus
What are the components of the parasympathetic nervous system?
- Cranial outflow- CN 3,7,9,10
- Sacral outflow
What are the components of the the sympathetic nervous system?
Sympathetic chain T1-L2
Adrenal gland
What receptors and neurotransmitters are present in the sympathetic ns?
ACh with a nicotinic receptor, then noradrenaline
- Receptors are alpha 1 (in smooth muscle) and alpha 2 (in blood vessels)
What receptors and neurotransmitters are present in the parasympathetic ns?
ACh with a nicotinic receptor, then ACh with a muscarinic receptor
- Receptors are beta 1 (in heart), beta 2 (in bronchi) or beta 3
Give an example of an acute and a chronic primary ANS disorder
Acute- Pan-dysautonomia
Chronic- Parkinson’s disease
How can the autonomic NS CVS problems be tested?
Testing BP
Testing BPM
Head up tilt test
What are the components of the striatum?
Putamen
Caudate nucleus
What are the components of the globus pallidus?
Internal segment
External segment
Where is dopamine produced and where does it act?
It is produced in the substantia nigra (melanin is produced as a byproduct). It acts on the axons in the striatum.
What is the pathalogical cause of parkinsons disease?
There is disease of the dopamine neurons in the substantia nigra so dopamine is not produced effectively.
The subthalamic nucleus is inhibited.
What is the pathalogical cause of Huntington’s disease?
The head of the caudate and the cortex shrinks making ventricles appear bigger (can be seen on a CT). This means that there is too much dopamine.
It is autosomal dominant and fully penetrant
What are the symptoms of Parkinsons?
Increased muscle tone Reduced movement Not enough dopamine Problems with doing up buttons/ keyboards Smaller writing Deteriorated walking; small steps, dragging one foot, feet close together, etc. Tremor at rest (may be on one side only) Pain
What are the treatments for Parkinsons?
L-DOPA (to correct dopamine deficit)- but becomes less effective and more side effects develop the longer that it is used
Deep brain stimulation- functional lesioning of the subthalamic nucleus
What are the symptoms of Huntington’s disease?
Chorea Dementia/psychiatric illness Personality change Decreased muscle tone Overshooting movements Too much dopamine
What is the treatment for choriform movements?
Dopamine receptor blockers
What is the WHO definition of mental health?
Mental health is a state of well being in which every individual realizes his or her own potential, can cope with normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community
List some CMHDs
Depression Generalized anxiety disorder Social Anxiety disorder Panic Disorder OCD PTSD Phobias
What are the symptoms of depression?
Loss of interest Decreased energy Feelings of guilt or low self worth Disturbed sleep or appetite Poor concentration These must last most of each day, every day for more than 2 weeks
How much more likely are women than men to have a CMHD?
2x more likely
What are some social determinants of CMHDs?
Low education Material Disadvantage Unemployment Debt Loneliness
What are the different levels of interventions for CMHDs?
Individual level
Service level
Community level
What is included in individual level intervention?
Medication, psychological therapy, CBT
Culturally sensitive
Collaborative
What is included in service level intervention?
Management within primary care, focusing on prevention and early identification
Holistic approach
Outcomes focused
Joining the gaps
What is included in community level intervention?
Strengthening protective factors e.g. programmes in schools
Reducign risk factors
What is IAPT and what is its goal?
Improving access to psychological therapy
Low or high intensity
Lower socio-economic groups are more likely to access treatment
Shorter waiting times
Describe the “take it easy” trap of chronic pain
Avoidance of activities due to concerns about doing harm, and avoiding activities associated with pain. The patient therefore does less and less over time, and has less contact with others. This can lead to a loss of fitness and depression.
What are the three P’s of pain management?
Pacing
Planning
Prioritising
What cells line the ventricles?
Ciliated ependymal cells
How does CSF drain?
Arachnoid granulations
Peripheral nerves to lymphatics
How does interstitial fluid drain into the CSF?
Perivascular channels
What nucleus does the superior colliculus communicate with?
Lateral geniculate nucleus of thalamus
What nucleus does the inferior colliculus communicate with?
Medial geniculate nucleus of thalamus
What does a small response from a NCS suggest?
Axonal degeneration
What does a slow response from a NCS suggest?
Demylenation
Briefly explain an EMG
Use a needle to pick up electrical activity from a muscle when the patient contracts it. Record the activity of individual motor units. Large motor unit- compensatory innervation, small motor unit- breakdown of muscle
Briefly explain an EEG
Electrodes are placed in specific locations on the head. Ask the patient to do various things such as close eyes.
What are the characteristics of a frontal lobe seizure?
Brief
Often arise in sleep
Fencing posture
