Neuro physiology 🧠 Flashcards

Question

Describe arborisation of axons and dendrites

Answer 1

Cortical projection neuron Cerebellar Purkinje cell

Answer 2

* 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 * Provide metabolic support for axons

Answer 3

* Formed by wrapping of axons by oligodendrocyte processes (membranes) * Highly compacted – 70% lipid, 30% protein * Myelin specific proteins, e.g. myelin basic protein (MBP) can be used as “markers

Answer 4

* Resident immune cells of the CNS * Originate from yolk sac progenitors that migrate into the CNS * “Resting” state, highly ramified, motile processes survey environment (2-3 µm/min) * Upon activation (e.g. by ATP), retract processes, become “amoeboid” & motile * Proliferate at sites of injury - phagocytic Not like the other types- more like macrophages

Answer 5

* Immune surveillance * Phagocytosis – debris/microbes * Synaptic plasticity – pruning of spine * "bad" (M1) and "good" (M2) microglia

Answer 6

* “Star-like cells” * Most numerous glial cells in the CNS * Highly heterogeneous – not all star-shaped * Common “marker” glial fibrillary acidic protein (GFAP) Contribute to the blood-brain barrier

Answer 7

Processes of astrocytes wrap around capillaries

Answer 8

* Structural - define brain micro-architecture * Envelope synapses – “tripartite synapse” – buffer K+, glutamate, etc * Metabolic support – e.g. Glutamate-Glutamine shuttle * Neurovascular coupling – changes in cerebral blood flow in response to neural activity * Proliferate in disease = gliosis or astrocytosis

Answer 9

* Radial glia –important for brain development * Bergmann glia (cerebellum) - green * Müller cells (retina)

Answer 10

* Abundance of neuronal cell bodies in nuclei * Axons gathered into tracts * Tracts that cross midline = commissures * Grey matter abundant in neural cell bodies & processes – neuropil contains few cell bodies * White matter contains abundance of myelinated tracts & commissures

Answer 11

* Cell bodies & supporting cells located in ganglia – e.g. dorsal root ganglia (DRGs) * Axons bundled into nerves * Many PNS axons are enveloped by Schwann cells (myelinating cells of the PNS – neural crest derived c.f. oligodendrocytes, derived from CNSresident neural progenitors)

Answer 12

* Dyes injected into blood penetrate most tissues, but not the brain * Dyes injected into CSF – brain stains → specialised blood-brain barrier * Formed by endothelial cell tight junctions, basement membrane (few fenestrations), astrocyte end feet & pericytes (contractile, aid blood flow) * Sensitive to inflammation, hypertension, trauma, ischaemia * Problem for drug delivery!

Answer 13

* Epithelial-like, line ventricles & central canal of spinal cord * Functions - CSF production, flow & absorption * Ciliated – facilitates flow * Allow solute exchange between nervous tissue & CSF

Answer 14

* Frond-like projections in ventricles * Formed from modified ependymal cells - villi form around network of capillaries → highly vascularised with a large surface area * Main site CSF production by plasma filtration driven by solute secretion * Gap junctions between ependymal cells form bloodCSF barrier

Answer 15

Learned threat- cortex and limbic system Loom- Sensorimotor midbrain Pain- spinal cord

Answer 16

“There are two kinds of foundation: mental and body” “The mental cannot exist outside of the body; and the body cannot think” “Thus: mental events cause physical events and vice-versa

Answer 17

What is this “non physical” substance which is not brain? How can an “immaterial” mind cause anything in a “material” body and vice versa Theory leads to explanations involving another being - soul, animal spirits, deity? Lack of scientific evidence for this

Answer 18

What about “inexplicable” symptoms? Or where “biological reductionism” does not explain symptoms? “functional, conversion, psychosomatic, medically unexplained, persistent physical symptoms, overlay, psychogenic, hysterical, manipulative, factitious, Munchausen’s ” How do we reflect the importance of the fact that the individual is part of a range of larger (social /political /cultural) systems? What is the impact of environment /society is critical in our perception of self and our wellbeing How do we think about dualism when the WHO defines health in positivist terms as: “a state of complete physical, mental and social well-being” or “the capacity, relative to potential and aspirations, for living fully in the social environment” (Tarlov)

Answer 19

Familiar: 300 years of medical experience Economics: private enterprise (Big Pharma?) rely on this paradigm Power: health is traditionally the business of doctors (or is it – currently being challenged) Convenience: ability to design experiments to test NB not only biological reductionism, can also have social reductionism (e.g postnatal depression is not “valid” as the experiences can be understood as the adaptation to a significant environmental change??)

Answer 20

Facilitate reporting and inform public health issues such as allocation of resources Facilitate meaningful communication and debate between patients, professionals, organisations and legislators Promote a feeling of being understood (“we’ve seen this before – your problems are not unique”) Provide a framework for research Offer evidence for treatment options and some information about natural history and prognosis

Answer 21

Improved scientific understanding makes a mockery of previous attempts to classify (e.g. phrenology) Categorisation means defining thresholds which are arbitrary depression / dysthymia / fed up obese / well built / chubby / slender Categorisation can lead to stigma and prejudice Economy of thought may lead to oversimplification, reductionism and ultimately inhumane action

Answer 22

Motivator for learning Means of best obtaining rewards/ avoiding punishment - Stimulus-reinforcer associations - Instrumental (action-outcome) learning

Answer 23

Ability to act s

Answer 24

-Biologically privileged emotion automatically triggered by oblects and events -Hard-wired circuits -Variability: cultural

Answer 25

- Meaningful interpretation of an object or a situation by an individual - Action readimess - May be automatic

Answer 26

Psychial compounds of basic ingredients (affect and ideational component) Same ingredients involved in other mental states Internal state subject of meanig analysis

Answer 27

-limbus -described by broca - emotion result of network of sirect and trans synaptic connections-# - no single limbic system network of connections

Answer 28

-Appraisal - input: ventral cortical streams (identity) 0 Medial- reward- activation: subjective to pleasantness Lateral- punishment/ non reward- negative reward prediction error- expectation of punishment

Answer 29

- Older brain overshadowed by OFC - conditions responses to stimuli predicting harm - facial expression recognition - Little involved in subjective emotional experience - slower response in verbal? learning tasks

Answer 30

Action- outcome learning Anterior- outcome- subgenual reward signals from ofc Supracallosal punishment/ non reward from lateral ofc posterior- action- input from parietal lobes (spatial/ action related info output hippocampus mid output to premotor area

Answer 31

Modulated by: OFC via anteroventral insula and subgenual cingulate cortex, amygdala- hypothalamus and periaqueductal grey feedback from autonomic output not needed for emotional behaviour/ feelings

Answer 32

Ectoderm thickens in midline to form the neural plate- neural tube and then eventually spinal canal

Answer 33

Notochord forms from mesoderm cells soon after gastrulation is complete

Answer 34

Signals from the notochord cause inward folding of the ectoderm at the neural plate

Answer 35

Ends of neural plate fuse and disconnect to form an autonomous neural tube

Answer 36

Stem cells Lateral to the neural groove lie presumptive neural crest cells in ectoderm form- melanocytes, schwann cells and neurons in mesoderm- osteoblasts, adipocytes and chondrocytes

Answer 37

Sensory dorsal root ganglia of spinal cord and V/VII/IX/X Schwann cells Adrenal medulla Bony skull Meninges

Answer 38

The neural tube usually closes at the end of 4th embryonic week Failure to close cephalic region – anencephaly Failure to close spinal region – spina bifida Collectively called – neural tube defects

Answer 39

Accumulation of CSF with increased intracranial pressure Can cause macrocephaly in children (therefore always scan increasing head size) Obstructive (non-communicating): e.g. tumour, haemorrhage. Non-obstructive (communicating): e.g. increased CSF production

Answer 40

CSF circulates through the subarachnoid spaces and through the ventricles CSF cushions the brain and helps circulate metabolites Around 120 mLs Produced as filtrate of blood at choroid plexuses in ventricules Absorbed via arachnoid granulations in superior sagittal sinus

Answer 41

Prosencephalon-cerebral hemispheres and thalamic structures Mesencephalon – midbrain Rhombencephalon – medulla, pons and cerebellum

Answer 42

Telencephalon Diencephalon Mesencephalon fourth ventricle rhombencephalon

Answer 43

cortex is thin in development but complicated layered structure in adults

Answer 44

Microcephaly – reduced head circumference Macrocephaly – increased head circumference

Answer 45

Basic cellular unit of the nervous system Huge range - specialised for different functions All have same basic components Approximately 100 billion (109) neurons in the ‘average’ brain But, 0.15 quadrillion (1015) connections between them (synapses)

Answer 46

Dendrites Cell body/soma Axon Presynaptic terminals

Answer 47

Multipolar neuron Bipolar neuron Pseudo-unipolar neuron Unipolar-neuron

Answer 48

Transmission of information from location A to location B

Answer 49

Integration/processing of information and transmission between neurons

Answer 50

Some substances which are electrically charged (+ve or –ve) cross readily – potassium (K+) and chloride (Cl-) Some cross with difficulty – sodium (Na+) Some not at all – large organic proteins (-ve charge)

Answer 51

Diffusion – the force driving molecules to move to areas of lower concentration

Answer 52

electrostatic attraction/repulsion Electrostatic pressure - ions (like magnets) move according to charge – Like ions repel and unlike attract Ions: A- (anions - protein) Na+ (sodium ions) + (potassium ions) Cl- (chlorine ions)

Answer 53

A- (anions - protein) - restricted to inside of cell Na+ (sodium ions) - mostly outside neuron K+ (potassium ions) - mostly inside neuron Cl- (chlorine ions) - mostly outside neuron

Answer 54

Active process to transport Na+ ions out of neuron & K+ in Three Na+ for every two K+ Require energy supplied by ATP

Answer 55

Result is NA+ high concentration outside but with both forces pushing in Membrane and pump resists Na+ inward movement K+ & Cl- can move backward and forward across membrane so reach steady state determined by opposing forces of diffusion and electrostatic pressure Some sodium leaks back in but is expelled by the pump

Answer 56

Neuron fires – a sudden pulse where the negative resting potential is temporarily reversed Transmits information i.e. the message [digitally / all or none / 0 or 1]

Answer 57

Depolarization & threshold Reversal of membrane potential Repolarisation to resting potential Refractory period

Answer 58

The membrane potential remains in this resting ‘stable’ state until something disturbs the balance:Membrane permeability changes Neurotransmitters initiate such changes at the dendrites of neurons

Answer 59

Neurotransmitters activate receptors on dendrites / soma Receptors open ion channels Ions cross plasma membrane, changing the membrane potential The potential changes spread through the cell If the potential changes felt at the axon hillock are positive (+mV), and large enough, an action potential is triggered

Answer 60

The voltage of the potential spread thru the cell

Answer 61

Excitatory neurotransmitters depolarise the cell membrane increases probability of an action potential being elicited cause an Excitatory Post Synaptic Potential (EPSP)

Answer 62

Inhibitory neurotransmitters hyperpolarise the cell membrane decreases probability of an action potential being elicited cause an Inhibitory Post Synaptic Potential (IPSP)

Answer 63

An action potential will be elicited if the membrane potential is depolarised beyond the threshold of excitation

Answer 64

Voltage changes spread away (decrementally) from point of origin (Passive Conduction). Whether AP is generated depends on what reaches the axon hillock.

Answer 65

Inhibitory post synaptic potential

Answer 66

Excitatory post synaptic potential

Answer 67

EPSPs begin to depolarise cell membrane Threshold ~ -60mV When reached Na+ channels open (Na+ rushes in) and polarity reverses to +30 inside Membrane potential reverses with the inside going positive …at which point voltage-gated Na+ channels close and K+ channels open (K+ rushes out) …which restores resting membrane potential

Answer 68

The voltage changes are caused by the opening or closing of ion channels In the cell membrane there are channels which are opened by voltage changes…thus voltage changes control the ion channels which control the voltage changes…….... The action potential is therefore self perpetuating

Answer 69

Receptors- (neurotransmitter activated ion channels) Summation Voltage activated ion channels open

Answer 70

Speeds up axonal conduction Allows the conduction of current as it means it can jump from nodes of ranvie

Answer 71

Signal loss due to lack of insulation –could be overcome by continual opening of next ion channel But SLOW due to time to activate each channel. Mainly short axon interneurons

Answer 72

Saltatory Conduction Decremental conduction between nodes (but ‘re-boosted’ each time) But very fast along axon. Most CNS neurons.

Answer 73

action potential triggers opening of voltage gated Ca+ channels to open This causes the vesicles in presynaptic terminal release neurotransmitter into the synapse

Answer 74

allows for modulation of signal charge spread charge slowed

Answer 75

Would remain active in synapse if it wasn’t for: Enzymatic Degradation Reuptake Acetylcholinesterase is the name of the enzyme that breaks down the neurotransmitter acetylcholine

Answer 76

Bottom up processing- sensation Top down processing- perception

Answer 77

A mental process resulting from immediate external stimulation of a sense organ Touch, smell, taste, sight hearing

Answer 78

The ability to become aware of something or understand something following sensory stimulation Tactile, olfactory, gustatory, visual, auditory

Answer 79

Psychological factors that determine how you perceive your environment

Answer 80

Context, culture, expectations, mood & motivation

Answer 81

Proximity, common fate, continuity, similarity, closure, common region, symmetry

Answer 82

An instance of a wrong or misinterpreted perception of a sensory experience Realise quickly

Answer 83

Experiences involving the apparent perception of something not present Cannot shake it quickly like illusion

Answer 84

Visual and auditory cortices

Answer 85

Drugs, delerium, sleep deprivation, psychiatric illness

Answer 86

SCHIZOPHRENIA DEPRESSION WITH PSYCHOSIS BIPOLAR AFFECTIVE DISORDER SCHIZOAFFECTIVE DISORDER DRUG INDUCED PSYCHOSIS ACUTE TRANSIENT PSYCHOSIS

Answer 87

Medication Psychologists Social networks

Answer 88

The organic illnesses The dependency states – alcohol; drugs The mood disorders The anxiety states The psychoses The behavioural disorders Neurodiversity Childhood disorders Personality disorders

Answer 89

Dementias Delerium

Answer 90

Alzheimer’s Rx - Acetylcholine esterase inhibitors Rx - Glutamate blockade Vascular dementia Subcortical Stoke related Multi-infarct Lewy body Frontotemporal

Answer 91

B12 and Folate deficiency Cushing’s disease Thyrotoxic storm Wilson’s disease And many more physical illnesses

Answer 92

Drugs: Key examples Heroin Cocaine Marijuana Alcohol

Answer 93

Depressive illness (Unipolar) Mania (Unipolar) Bipolar (Manic-depression) Cyclothymia Low mood (adjustment disorders, burnout, life setting)

Answer 94

Generalised anxiety disorder Panic attacks OCD Derealisation-depersonalisation

Answer 95

Schizophrenia Acute and transient psychosis Monosymptomatic delusion Post-natal (Puerperal) psychosis Drug induced psychosis

Answer 96

Sleep Sex Eating Habits

Answer 97

Anxiety Gender identity Appetite Dampens startle response Social recognition Parental bonding

Answer 98

The developmental ‘disorders’ Autistic spectrum ADHD Learning disability

Answer 99

Medial PFC Posterior CC Angular gyrus Precuneus

Answer 100

Separation anxiety General anxiety states School refusal Other behavioural problems Sexual, psychological and physical abuse

Answer 101

Many recognised types Two key examples Borderline PD Dissocial PD

Answer 102

Positive stress which is beneficial and motivating; typically, the experience of striving for a goal which is within reach

Answer 103

Negative stress which is damaging and harmful. Typically occurs when a challenge (or threat) is not resolved by coping or (rapid) adaptation. The type of stressor is less important than how it is experienced ie negative (threat) or positive (challenge), whether it is experienced physically and/or psychologically and how long it goes on.

Answer 104

Stresses are physical and psychological. Different neuronal networks are involved but these are connected.

Answer 105

Stress responses are often characterised as either physiological or psychological (mind). But these overlap and both are mediated via the brain.

Answer 106

(processed in brainstem & hypothalamus: reflexive) Insults or injuries that produce direct physiological effects eg damage of body tissue and/or bodily threat (eg pain, haemorrhage or inflammation).

Answer 107

(Involving PFC, amygdala and hippocampus) Stimuli that are perceived as excessively demanding or threatening, often involving anticipation.

Answer 108

Alarm, adaptation, exhaustion

Answer 109

Threat identified; body's response is state of alarm (fight or flight)

Answer 110

Body engages defensive countermeasures

Answer 111

Body runs out of defences and resources are depleted

Answer 112

Stress as “non-specific response of the body to any demand for change”. Selye (1907-1982) found that different insults caused the same disease (eg heart attacks, stroke, kidney disease and rheumatoid arthritis). Early evidence of neuroendocrine mechanisms and role of HPA axis.

Answer 113

Maintaining internal environment necessary for cell functioning

Answer 114

How complex systems adapt (eg via HPA axis) to changing environments by changing set-points (“adaptation through change”).

Answer 115

refers to cumulative exposure to stressors (and cost to the body of allostasis), which if unrelieved leads to systems ‘wearing out’.

Answer 116

Continued attempts to restore balance have long-term effects on physiological systems, including structural changes (eg to the CNS).

Answer 117

Brief response to a novel but short-lived situation experienced by the body as a danger. Conscious perception of threat is not always involved. The acute stress response (‘fight or flight’) is healthy & adaptive and necessary for survival.

Answer 118

Arises from repeated or continued exposure to threatening or dangerous situations, especially those that cannot be controlled. More likely than acute stress response to involve appraisal and conscious perception.

Answer 119

- Physical illness, disability & pain - Physical or sexual abuse - Poverty including poor housing, hunger, cold or damp, debt - Unemployment - Bullying or discrimination - Caregiving

Answer 120

Individual differences are important, including differences in perception of threat & control and physiological differences in the timing and duration of the stress response

Answer 121

Biochemical Physiological Behavioural Cognitive Emotional

Answer 122

Stress responses are generic and not stressor-specific. Stress responses mediated via autonomic nervous system (ANS) and the hypothalamo-pituitary (HPA) axis. These responses lead to changes that influence future responses to stress, also reflecting brain plasticity.

Answer 123

hypothalamus activates adrenal medulla -> Adrenal medulla releases adrenaline and noradrenaline into the bloodstream -> Body prepares for fight or flight, adrenaline and noradrenaline reinfordes bthe pattern e.g increased hr and bp -> Energy

Answer 124

Steroids especially glucocorticoids (cortisol) Catecholamines (adrenaline & noradrenaline) The so-called sympathetic nervous system (SNS) ‘fight-or-flight’ chemicals

Answer 125

are important & complex, mediated and modified by adrenaline and cortisol. Effects can be pro- and anti-inflammatory, and GCCs also have direct effects on the CNS. Balance between immune activation & autoimmunity disrupted in chronic stress response (NB reduced vaccination response) Immunosenescence?

Answer 126

Immune suppression (anti-inflammatory)

Answer 127

Partial immune suppression + low-grade chronic inflammatory response, possibly through epigenetic effects on gene expression

Answer 128

Breathing more rapid to increase oxygen Blood flow increases up to 400%, directed to heart & muscles Increased heart rate & blood pressure Muscles tense Glucose released, insulin levels fall: boost energy to muscles Red blood cells discharged from the spleen Mouth becomes dry & digestion is inhibited Sweating Cytotoxic & surveillance WBCs go where injury & inflammation may occur i.e. bone marrow, skin, lymph nodes

Answer 129

Headache Chest pain Stomach ache Musculoskeletal pain Low energy Loss of libido Colds & infections Cold hands & feet Clenched jaw & grinding teeth

Answer 130

- Easily startled & hypervigilant Change in appetite – both directions Weight gain (obesity) or weight loss Procrastinating and avoiding responsibilities Increased use of alcohol, drugs & smoking Nail biting, fidgeting and pacing Sleep disturbances especially insomnia Withdrawal

Answer 131

- Constant worrying - Racing thoughts - Forgetfulness and disorganisation - Inability to focus - Poor judgement - Being pessimistic or seeing only the negative side - Altered learning

Answer 132

- Depression & sadness - Tearfulness - Mood swings - Irritability - Restlessness - Aggression - Low self-esteem and worthlessness - Boredom & apathy - Feeling overwhelmed - Rumination, anticipation & avoidance

Answer 133

Anticipatory reaction Lack of recovery- stress decreases at normal rate but doesn't fully stop Lack of habituation response continues for a while but does decrease Lack of habituation and recovery- response doesn't decrease and doesn't go away

Answer 134

Ppl vary Different parts of the brain mediate responses to different types of stressor (but amygdala and hippocampus are key). Context, appraisal, vulnerability and learning (past experience) modify perception of threat and hence the stress response. People exposed to adversity in early life are more sensitive to stress later on. Stress mechanisms alter affect (mood, anxiety levels). This is likely to mediate the effects of stress on other bodily systems including through behaviours (eg alcohol, diet etc).

Answer 135

Stress is related to a host of illnesses, esp of cardiovascular and GI systems, ie those with strong ANS connections. Stress exacerbates physical illnesses and slows recovery and increases susceptibility to infection. Strong evidence of association between depression and mortality following an MI. Evidence of causal association between stress and physical illness is still limited, though note emerging evidence that chronic stress increases ‘immune ageing’. Exposure to stress (trauma)

Answer 136

- Cancer: stress linked to survival rather than incidence - Cardiovascular disease: high blood pressure, abnormal heart rhythms, MI and stroke - Obesity & eating disorders - Infertility, recurrent miscarriage & menstrual problems - Rheumatoid arthritis - Skin & hair problems eg acne, psoriasis, eczema - Gastrointestinal problems: inflammatory bowel disease, irritable bowel syndrome. - Medically unexplained symptoms (MUS) - Infectious diseases especially covid-19

Answer 137

- Vivid flashbacks & nightmares - Intrusive thoughts and images - Sweating - Nausea - Trembling - Hypervigilance & increased startle response - Agoraphobia - Insomnia - Irritability - Impaired concentration

Answer 138

- Shiatsu, T'ai Chi, Yoga - Mindfulness - Meditation - Exercise - Sleep hygiene - Friends and family - Healthy diet - Exposure to natural environments - Aromatherapy - Cognitive Behavioural Therapy

Answer 139

Ask questions about why natural selection has left us vulnerable to developing mental disorders

Answer 140

Ontogeny mechanism phylogeny adaptive significance

Answer 141

Mismatch- body unable to cope with modern environment Infection- bacteria and viruses evolve faster than us Constraints- some things evolution can't do Trade off- everything has advantages and disadvantages Reproduction- ns maximises reproduction not health Defensive responses- responses such as pain and anxiety are useful in the face of threats

Answer 142

Want alarm system to go off if there is an actual fire- benefits So false alarms happen to err on the side of caution

Answer 143

Manufacture – intracellular biochemical processes Storage – vesicles Release – by action potential Interact with post-synaptic receptors – diffusion across the synapse Inactivation – break down or re-uptake

Answer 144

– short lasting effects Acetylcholine (ACh) Glutamate (GLU) Gamma-aminobutyric acid (GABA)

Answer 145

slower timescale Dopamine (DA) Noradrenalin (NA) (norepenephrine) Serotonin (5HT) (5-hydroxytryptamine)

Answer 146

A region of the brain engaged in a particular function uses several neurotransmission systems e.g. basal ganglia Glutamate GABA Dopamine Acetylcholine Substance P Enkephalin Regions of the brain engaged in different functions use the same neurotransmission systems Glutamate GABA Acetylcholine Serotonin Dopamine/Noradrenalin

Answer 147

Hallucinogenic drugs include LSD, Magic Mushrooms, Ketamine They mimic serotonin, and can activate numerous different serotonin receptor subtypes But the hallucinogenic effect itself appears to be specifically related to the way they target the serotonin ‘2a’ receptor (5-HT2a)

Answer 148

- Involuntary: eye movements, facial expressions, jaw, tongue, postural muscles throughout trunk, hand and fingers, diaphragm, cardiac, intercostals (around lungs), digestive tract…… - Goal-directed: conscious, explicit, controlled. - Habit: unconscious, implicit, automatic - Voluntary: running, walking, talking playing guitar etc.,……

Answer 149

Motor control governed by lower and upper motor neurons. The lower motor neuron begins (has its cell body) in brainstem or spinal cord and projects to the muscle The upper motor neurons originate in higher centres and project down to meet the lower motor neurons

Answer 150

Muscles can only contract or relax (i.e. stop contracting) The activation of muscle fibres is all or none So how do we achieve such a range of movements and forces ?? Antagonistic arrangement – combined co-ordinated action Recruitment of muscle fibres – fast/slow twitch, small and large motor units (see later)

Answer 151

The number of muscle fibres varies across individuals, but changes little with either time or training – appears to be genetically determined Muscle size (+ strength) is more about cross sectional area of individual fibres and different proportions of the different types of fibre (see later)

Answer 152

A skeletal muscle is attached to the bone by the tendon A skeletal muscle comprises several muscle fasciculi (group of muscle fibres) A muscle fasciculus comprises several muscle fibres (= muscle cells) A muscle fibre is constituted of several myofibrils Myofibrils contain protein filaments: Actin and Myosin myofilaments When the muscle fibre is depolarised actin and myosin slide against each other which produce muscle contraction

Answer 153

The release of acetylcholine causes a cascade of events resulting in the release of packets of calcium from inside the muscle cell (fibre) This causes the myosin head to change shape, enabling it to bind with the actin filament ATP (provides energy for cells) is required to break the bond between the myosin head and the actin filament ATP is produced by oxidative metabolism, which stops upon death So the muscle become contracted and remain that way until enzymes begin to disrupt the actin/myosin

Answer 154

Single alpha () motor neuron + all the muscle fibres it innervates – Different motor neurones innervate different numbers of muscle fibres – fewer fibres means greater movement resolution - those innervating finger tips and tongue

Answer 155

The motor unit is the final common pathway for motor control Activation of an alpha motor neuron depolarises and causes contraction of all muscle fibres in that unit (all or none) Muscle fibres innervated by each unit are the same type of fibre and often distributed through the muscle to provide evenly distributed force (and may help reduce effect of damage) More motor units fire – more fibres contract – more power

Answer 156

Average number of muscle fibres innervated by single motor neuron (a motor unit) varies according to two functional requirements for that muscle: 1. Level of control 2. Strength Typically a range of motor units in a muscle, some with few, some with many fibres.

Answer 157

Units are recruited in order of size (smallest first) Fine control typically required at lower forces Try playing the violin with weights attached to your arms!!

Answer 158

Slow Fast fatigue resistant Fast fatigable

Answer 159

All the lower motor neurons that innervate single muscle The motor pool contains both the alpha and gamma motor neurons (see later) Motor pools are often arranged in a rod like shape within the ventral horn of the spinal column

Answer 160

Cell bodies in the ventral horn: activated by: Sensory information from muscle Descending information from brain

Answer 161

Muscles can be contracted or relaxed to provide movement, but a good control system (the CNS) needs to know two things: how much tension is on the muscle- golgi tendon organs sense tension what is the length (stretch) of the muscle- muscle spindles sense stretch

Answer 162

The GTO is within the tendon (where the muscle joins to bone) Mostly, it sends ascending sensory information to the brain via the spinal cord about how much force there is in the muscle Critical for proprioception Under conditions of extreme tension, it is possible that GTOs act to inhibit muscle fibres (via a circuit in the spinal cord) to prevent damage

Answer 163

Muscle spindles sense the length of muscles, i.e. the amount of stretch This information forms a key part of reflex circuits…….

Answer 164

Ones that do stuff

Answer 165

Sensory neuron connected so it can sense stretch

Answer 166

Quadrupeds will walk on treadmill if weight supported if spinal cord damaged at thoracic level Will change to appropriate patterns of limb movement as treadmill speed is altered Complex reflex system responding to nothing more than stretch of muscle spindles!!

Answer 167

Reciprocal Innervation Principle described by Sherrington (also called Sherrington’s Law of reciprocal innervation) Reciprocal innervation of antagonistic muscles explains why the contraction of one muscle induces the relaxation of the other Permits the execution of smooth movements

Answer 168

Pathways and nuclei within the brainstem (and midbrain) connect sensory input to motor output in quite direct ways, providing an evolutionarily ancient but still very important control system. E.g balance and speech

Answer 169

Primary motor cortex exerts quite direct, top down control over muscular activity, with as few as one synapse (in the spine) between a cortical neuron and innervation of muscle cells

Answer 170

Motor command originates in motor cortex pyramidal cells (in layer 5-6, grey matter). These are the upper motor neurons. Pyramidal cell axons project directly or indirectly (e.g. via brainstem) to spinal cord, where they synapse with lower motor neurons. The axons of these upper motor (pyramidal) neurons form the pyramidal tract Most cortical projections innervate contralateral motor units

Answer 171

Basal ganglia- inhibitory Cerebellum- excitatory

Answer 172

Homunculus is a reasonable representation, but an oversimplification: damage to a single finger area doesn’t mean loss of voluntary control of that finger. Representations are more complex and overlapping After all, few motor commands require isolated activation of a single motor unit

Answer 173

In spinal white matter Innervate contralateral side of one segment of spinal cord Sometimes project directly to alpha motor neuron Project to distal muscles, e.g. fingers

Answer 174

Direct route Diffuse innervation projecting to both sides and multiple segments of spinal cord Project to proximal muscles of trunk and limbs

Answer 175

A group of structures beneath the cortex that act as a ‘gate-keeper’ for control of the motor system (muscles) - The basal ganglia are a group of nuclei lying deep within cerebral hemispheres - Widely studied (including here at Sheffield) - Role in motor control not fully understood- inhibitory - Basal ganglia dysfunction implicated in many disorders

Answer 176

Receives excitatory input from many areas of cortex (Glutamate) Output goes back to cortex via the thalamus Output is mainly inhibitory (GABA) Complex internal connectivity involving 5 principle nuclei

Answer 177

Multiple command systems Spatially distributed Processing in parallel All act through final common motor path [Cannot do more then one thing (well) at a time] How do you resolve the competition?

Answer 178

dopamine drives disinhibitory effect

Answer 179

The cerebellum is a large brain structure that acts as a ‘parallel processor’, enabling smooth, co-ordinated movements. It may also be very important in a range of cognitive tasks Like basal ganglia, no direct projection to the lower motor neurons – instead modulate activity of upper motor neurons

Answer 180

Contains approx half total number of CNS neurons Just 10% of total brain weight Projects to almost all upper motor neurons

Answer 181

Cerebral cortex via pons Vestibular system spinal cord

Answer 182

Via thalamus to motor cortex

Answer 183

-It knows what the current motor command is -It knows about actual body position and movement -It projects back to motor cortex Computes motor error and adjusts cortical motor commands accordingly

Answer 184

Not just motor control, but motor learning too, in collaboration with basal ganglia and cortical circuits. Functional brain imaging studies have demonstrated that the cerebellum is involved in a wide variety of non-motor tasks

Answer 185

Record brain activity Decode Specify desired movement sequence Move limbs

Answer 186

Emmetropia- normal vision Myopia- short sightedness as refractive power is too high Hypermetropia- long sightedness as refractive power is too low

Answer 187

Underpowered to focus near objects on the retina May be due to: Corneal curvature too shallow Lens not flexible enough Axial length of eyeball too short

Answer 188

Vitreous humour Avascular viscoestalic gel Hyaluronic acid (GAG) Collagen

Answer 189

Lids- protect the globe Anterior skin Eye lashes Melbomian glands Orbicularis oculi Tarsal plate Tarsal conjunctiva Levator palpebrae superioris and sympathetic muscle Conjunctiva- palpebral (tarsal) vs bulbar (ocular) Limbal stem cells Conjunctival fornix Mucous membranes (goblet cells) Lymphoid cells ( protective) Tear film

Answer 190

Anterior skin Eye lashes Melbomian glands Orbicularis oculi Tarsal plate Tarsal conjunctiva Levator palpebrae superioris and sympathetic muscle

Answer 191

palpebral (tarsal) vs bulbar (ocular) Limbal stem cells Conjunctival fornix Mucous membranes (goblet cells) Lymphoid cells ( protective)

Answer 192

3 layers- anterior lipid, middle aqueous, posterior mucous Protective Nutrition for cornea

Answer 193

- Internal carotid a. -> Ophthalmic a. - Branches of the ophthalmic a. (ocular group): - central retinal a. - Posterior ciliary a. -> long and short - muscular a. -> anterior ciliary a. - Branches of the ophthalmic artery (orbital group: - lacrimal a. - several other branches supply the face and lids - External carotid a. -> facial a. -> angular a.

Answer 194

Pain due to a stimulus that does not normally provoke pain.

Answer 195

An unpleasant abnormal sensation, whether spontaneous or evoked.

Answer 196

Increased pain from a stimulus that normally provokes pain.

Answer 197

Diminished pain in response to a normally painful stimulus.

Answer 198

Peripheral receptor 1st order neuron 2nd order neuron 3rd order neuron

Answer 199

to detect the relevant stimulus

Answer 200

- from the periphery to the ipsilateral spinal cord

Answer 201

which crosses to the contralateral cord and ascends to the thalamus, the system’s integrative ‘relay station’

Answer 202

rom thalamus to midbrain and higher cortical centers

Answer 203

Transduction Physical stimulus  action potential Most are poly-modal (thermal / chemical / mechanical)

Answer 204

Nociceptors are the free nerve endings of primary afferent neurons AΔ fibres C fibres found in any area of the body that can sense pain either externally or internally External: skin / cornea / mucosa Internal: viscera / joints / muscles / connective tissue The cell bodies of these neurons reside in either Dorsal root ganglion (body) Trigeminal ganglion (face / head / neck)

Answer 205

Present on the dorsal root (sensory) Composed of cell bodies of nerve fibres that are sensory (afferent) First order neurons Pseudo-unipolar neurons Can be the source of pain pathology Trigeminal ganglion is the equivalent for the face / head

Answer 206

Info carried- proprioception Myelin sheath?- yes Diameter(micrometers)-13- 20 Conduction (m/s)- 80-120

Answer 207

Info carried- touch Myelin sheath?- yes Diameter (micrometers)- 6-12 Conduction- 35-90

Answer 208

Info carried- pain (mechanical and thermal) Myelin sheath?- yes Diameter 1-5 Conduction 5-40

Answer 209

On the posterior aspect of the SC the grey matter forms two horns called the dorsal horns. (the ones at the front are called the ventral horns) Contains distal nerve endings from primary afferents, cell bodies of second order neurones as well as a complex network of other nerves such as excitatory and inhibitory interneurons (and projection neurones) that transmit somatosensory info from the SC to the brain 1952 Rexed subdivided the grey matter of the SC into 10 laminae. Lamina 1 5/6 correspond to the DH. Some of these rexed laminae have special names e.g. lamina II (2) is called substantia gelatinosa

Answer 210

Aδ primary afferents synapse directly with secondary afferents that will eventually carry the pain signal to the thalamus. C fibres do not synapse directly with secondary afferents, but connect instead with interneurons that carry the signal on to secondary afferents in laminae I or V. These interneurons are important in modulation of the pain signal Visceral input differs in that fewer primary afferents activate a larger number of second order neurons, resulting in poorer localisation of pain. Visceral afferents also converge with somatic inputs, which may account for the phenomenon of referred pain

Answer 211

Sensory pathway that carries pain, temperature and crude touch information from the body 2nd order neurons Originate in the spinal cord (substantia gelatinosa and nucleus proprius) Axons decussate at / few levels above the site of entry / spinal segment Cross the midline in the anterior commissure Then form the anterolateral tract lateral STT (pain & temperature) and anterior STT (crude touch) Terminate in the thalamus (ventral posterior lateral nucleus)

Answer 212

Doral columns- fine touch, proprioception, vibration) Lateral spinothalamic tract- pain and tgemperature Ventral spinothalamic tract- light touch

Answer 213

Midline, paired symmetrical structure in the brain Approx 6 X 3 cms long All sensations (except olfactory) relay / pass through Multiple nuclei VPL Medial group Reciprocal connections to all parts of the cortex

Answer 214

severity of pain and addiction

Answer 215

emotional processing of pain

Answer 216

Emotional formation around pain

Answer 217

Grey matter located around the cerebral aqueduct Receives input from cortical and sub-cortical areas Projects onto neurons in the dorsal horn Modulate afferent noxious transmission Neurons bear opioid receptors Pathways also include noradrenergic and serotonergic neurones Stimulus of the PAG can result in profound analgesia

Answer 218

Pain affects all areas which then affects the pain

Answer 219

Beliefs and emotional response pain behaviours- being told something about how you should cope with pain affects how you will cope with it and its duration

Answer 220

Pain perception and relationship between work and health

Answer 221

System or contextual obstacles e.g ongoing lawsuit

Answer 222

This schematic has drawn a gate to illustrate what inhibitory interneurons would do functionally What you have to know about Melzack and Walls gate control theory is that it is the concept that onwards transmission of a nociceptive signal depends on the balance between inhibitory and excitatory inputs at points of integration along the path from transduction to perception.

Answer 223

NSAID’S Paracetamol Opioids LA’s ⍺2 agonists NMDA receptor antagonists TCA’s gabapentinoids SNRI’s

Answer 224

Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.

Answer 225

Pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors, or evidence for disease or lesion of the somatosensory system causing the pain.

Answer 226

Pain caused by a lesion or disease of the somatosensory nervous system

Answer 227

Pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors.

Answer 228

Acute- physiological- Pain < 12 weeks duration Chronic- pathological- Continuous pain lasting > 12 weeks Pain that persist beyond the tissue healing time classified into cancer and non-cancer pain

Answer 229

Transduction in the periphery, through transmission to the dorsal horn of the spinal cord, then on to the brain

Answer 230

Describes the neural processes involved in producing the sensation of pain

Answer 231

Later, persisting pain encourages us to immobilize the injured area, giving damaged tissue the best chance to heal.

Answer 232

Immediate pain warns of imminent tissue damage  withdraw from the source of injury

Answer 233

-Low mood, anhedonia, low energy -“Biological” symptoms ◦ Poor sleep ◦ Poor appetite ◦ Reduced libido ◦ Poor concentration -“Cognitive” symptoms ◦ Worthlessness (poor self esteem) ◦ Guilt ◦ Hopelessness ◦ Suicidal thought

Answer 234

- Increased CRH - Enlarged adrenals and pituitary - Reduced –ve feedback - Reduced GR expression in the brain ◦ “Glucocorticoid resistance”

Answer 235

Hypothalamus --(CRH- corticotropin releasing hormone)----> Anterior pituitary ---(ACTH- adrenocorticotropic hormone)---> Adrenal cortex ---(CORT)----> Negative feedback to the hypothalamus

Answer 236

History of childhood maltreatment (with or without current MDD) -> ↑ACTH release in response to stress  Offspring of “high licking” lab rats show high GR expression (higher ACTH suppression) ◦ Even if swapped at birth ◦ Or even if brushed by a research assistant! ◦ Blocked by 5HT antagonists ◦ Possibly oxytocin mediated

Answer 237

Subordinate monkeys have: ◦ Heavier adrenal glands. ◦ Increased cortisol in hair ◦ Reduced dexamethasone suppression

Answer 238

Findings suggest that steroids are: ◦ Neurotoxic ◦ Cause neuro-vulnerability ◦ Affect dendrite formation ◦ Reduces neurogenesis ◦ Cause changes to the EEG.  Particularly affects the frontal lobes and hippocampus.

Answer 239

 Medial PFC ◦ Evaluating emotional state ◦ Social cognition ◦ Less volume loss  Dorsolateral PFC ◦ Working memory ◦ Problem solving ◦ Large volume loss

Answer 240

 Reduced in size in MDD ◦ Up to 20% volume loss  A dose related effect ◦ Correlated with number of, and length of previous episodes.  Associates with learning based cognitive deficits.  Much of the volume loss is irreversible ◦ Is depression a neurodegenerative disease?

Answer 241

 Grow axons and dendrites, and integrate into existing networks  6% of the total dendate gyrus population a month!

Answer 242

 Restraint and shock stress causes reduced neurogenesis. Particularly when learned helplessness is induced.  ‘Social dominance stress’ reduces the number of surviving new cells (same rate)

Answer 243

Mediated by reduced neurotrophins  Eg. Brain derived neurotrophic factor (BDNF)

Answer 244

Stress -> ↓BDNF (animals). ◦ Reversed with antidepressants  Low BDNF in unmedicated depressives ◦ Normal to high in medicated patients  The lowest levels in post-mortems of successful suicide victims

Answer 245

- Original observations about their pharmacology -> ◦ “The monoamine theory of depression” - The answer is “by affecting gene expression” - Antidepressants increase GR expression ◦ (regulating HPA activity) - Antidepressants increase neurogenesis  They increase BDNF synthesis. ◦ ∴ improve connectivity and increase number of synapses.

Answer 246

It’s what comes on when there’s nothing to do (“resting state”) - The brain’s ‘screen saver’ - Daydreaming, internal ‘flow’ of consciousness. - Autobiographical details ◦ The self’s place in time and space ◦ Projecting to other places in time and space - Self reference ◦ Referring to traits or states ◦ Emotional and moral reasoning - Thinking about others ◦ Theory of mind ◦ Social judgements/evaluations

Answer 247

- Depressed people find it hard to appropriately switch off their DMN in response to a task.1 - We already knew depressed people excessively ruminate. - Dinner party with a deadline.

Answer 248

- Carhart Harris used modern functional scanning techniques on people in the acute psychedelic state. - Positive symptoms -> ?surely increased activity - Reduced activity in the DMN - Reduced alpha power in PCC

Answer 249

- Physical activity - Connect with others - Learn something new - Practice mindfulness - Acts of generosity

Answer 250

S:Conscious- A: unconscious S: no synapse after CNS - A: fibres synapse at a ganglion after the CNS S: SkM, stimulatory - A: SmM and CM stimulatory and inhibitory

Answer 251

Cranial nerves to head, thorax + abdm Sacral outflow to pelvic organs The vagus nerve to thorax and abdm

Answer 252

Cranial nerves to eye The sympathetic chain Other ganglia Post ganglionic fibres

Answer 253

In the middle of the motor neuron Before it is myelinated after it is not Usually uses acetyl choline or NE at the neuromuscular junction

Answer 254

Thermoregulation, Exercise, Digestion, Competition, Sexual Function, Fight/flight

Answer 255

Heart rate and force of contraction increases Blood vessel constriction Bronchodilation] Decreased motility in gut Sphincter contraction Decreased secretion in gut Male ejaculation

Answer 256

Heart rate and force of contraction decrease Blood vessels can dilate Bronchoconstriction Increased gut motility Sphincter relaxation Increased secretions in gut

Answer 257

Sympathetic chain running alongside spinal cord

Answer 258

parasymp acetyl choline symp adrenaline/noradrenaline

Answer 259

Oculomotor III Facial nerve VII Glossopharyngeal nerve IX Vagus nerve X

Answer 260

Only in parasympathetic

Answer 261

Only in sympathetic

Answer 262

Alpha- alpha 1, alpha 2 Beta- beta 1,2,3

Answer 263

Carotid body in carotid bifurcation Baroreceptors for BP Chemoreceptors for O2 Afferents to the brainstem Affect output of brainstem

Answer 264

Volume in ventricle

Answer 265

Pan-dysautonomia with neurological features

Answer 266

Pure autonomic failure Multiple system atrophy (Shy-Drager syndrome) Autonomic failure with Parkinson’s disease

Answer 267

Diabetes mellitus Chronic renal failure Chronic liver disease Alcohol induced

Answer 268

Inflammatory- Guillian-Barré syndrome Infections- Bacterial: tetanus Parasitic: Chagas’ disease Viral: HIV Neoplasmia- Brain tumours, especially of third ventricle or posterior fossa

Answer 269

Postural hypoternsion Supine hypertension Liability of BP Paroxysmal hypertension Tachycardia Bradycardia Fainting

Answer 270

Erectile failure Ejaculatory failure Retrograde ejaculation Priapism

Answer 271

Hypo/anhidrosis Hyperhidrosis Gustatory sweating hypothermia Hyperpyrexia

Answer 272

Gastric stasis Dumping syndrome Constipation Diarrhoea

Answer 273

Pupillary abnormalities Ptosis Alachryma

Answer 274

HR and BP- preferably beat by beat -> can do it using the radial artery Tilt test Baro-reflex testing- By Phenylephrine test

Answer 275

Pupillometry Sweat measurement Skin blood flow, thermoregulation Gastric acid secretion Sexual function

Answer 276

- BOLD contrast reflects blood flow changes secondary to neuronal activation - Simple or complex tasks compared with a “rest” state - Statistical analysis of significant changes in BOLD contrast demonstrates areas of “activation” which are overlaid on anatomical images

Answer 277

- Study the auditory pathway both in cortical & subcortical structures - 3T -HIGH Resolution 2x2x2 mm3 -HIGH SENSE factor 2.5 -“Silent gap” scanning -Binaural auditory stimulation

Answer 278

An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage

Answer 279

Body/nervous system Attention Expectation Past experience (incl. trauma) Thoughts/words Senses Emotions Feedback/response

Answer 280

DIM- Danger SIM- Safety

Answer 281

- Sensitisation - catastrophic thinking - not only more likely to experience pain, but more likely to have an acute pain become chronic - situation where sustaining an injury would have high levels of consequence - more general psychological states of threat (e.g. abuse)

Answer 282

- Neurons that fire together (path through the woods) (playing the pain song) - Nervous system - “Smudging” etc.

Answer 283

A warning – (generally) helpful and protects you from further physical damage Can usually be explained and treated E.g. toothache, sprained ankle, broken bone Others tend to understand and offer sympathy Temporary - you can carry on as normal afterwards

Answer 284

Typically serves no useful warning purpose – a ‘nuisance’ Medical investigations may not provide a diagnosis or an explanation Treatment is aimed at relieving pain, not curing it Others might not understand Ongoing and often has a negative and widespread effect on life

Answer 285

Ability to work Activities (e.g. social and daily activities) Satisfaction and enjoyment from activities Contact with others Relationships with family and friends Self confidence Sleeping patterns Poor concentration Mood Sense of self -‘Not the person I used to be’ pre-occupation with pain Uncertainty about the cause of pain and the future

Answer 286

- Pacing - Prioritising - Planning

Answer 287

Limiting the time spent on an activity to prevent marked increases in pain, and keeping to a regular amount of activity to prevent the problems of too much rest. Planning activity rather than just doing things according to how you feel. Taking frequent short breaks, breaking tasks or activities down to smaller tasks and changing position regularly.

Answer 288

Involves thinking about when and how activities are going to be done. Make sure that difficult activities are spread out Balance essential with non-essential activities Taking regular breaks

Answer 289

Means making (difficult) choices about what is done Try to balance what needs to be done with what is pleasurable or interesting.

Answer 290

When we know something is going to hurt the natural and automatic response is for our muscles to tense up in anticipation to protect ourselves Pain leads to muscle tension Egs: something being thrown at us, injections Muscle tension can make the experience of pain worse

Answer 291

cause aches, discomfort and tiredness cause simple movements, e.g. walking or getting out of a chair, to become stiff and slow become normal - maybe physically tense without being aware of it

Answer 292

Be beneficial to a person’s general health Help to change their experience of pain Help to manage pain and feel more in control Be a useful means of distraction Be helpful in dealing with stress

Answer 293

Pain is a powerful signal which gets your attention, but we can influence that attention Awareness of pain is affected by mental activity Distraction is a very valuable and practical approach to managing pain

Answer 294

Help patients Plan for flare ups Remember the ‘box of tools’ Advise patients to talk to others about flare ups and how best they can help Advise patients to focus on getting through the short period of time during a flare up. Review medication use during and after a flare up.

Answer 295

-Motor circuit -Limbic circuit -Oculomotor circuit

Answer 296

Parkinson’s Disease Huntington’s Disease Dystonia Gilles de la Tourette syndrome

Answer 297

Obsessive compulsive disorder Attention Deficit Hyperactivity Disorder (ADHD)

Answer 298

Cerebral Palsy Wilson Disease

Answer 299

Increased muscle tone Reduced movements Not enough dopamine

Answer 300

-Decreased muscle tone -Overshooting movements -Too much dopamine

Answer 301

-Tyrosine- amino acid -L-DOPA -Dopamine

Answer 302

loss of dopaminergic receptors in the substantia nigra Presence of lewy bodies

Answer 303

GABA- produced in striatum

Answer 304

Substantia nigra

Answer 305

Loss of substantia nigra means decreased dopamine and so more GABA and less movement

Answer 306

Loss of striatum means loss of GABA so more dopamine and more movement

Answer 307

Brady/Akinesia Problems with doing up buttons, keyboard etc Writing smaller Walking deteriorated: Small steps, dragging one foot etc Tremor At rest May be on one side only Rigidity Pain Problems with turning in bed

Answer 308

Drugs mostly aim at correction of dopamine deficit But: More and more cells die The drugs work shorter and shorter The longer on treatment, the more likely are the patients to develop side effects, in particular dyskinesias

Answer 309

Functional lesioning of the subthalamic Nucleus leads to dramatic improvement of PD It deactivates the break (subthalamic nucleus)

Answer 310

Chorea Dementia/psychiatric illness Personality change

Answer 311

Autosomal dominant Fully penetrant Trinucleotide repeat expansion

Answer 312

Trinucleotide repeat expansion

Neuro physiology 🧠 Flashcards

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