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Biopsych (The Nervous System (Neurotransmitters (NEUROTRANSMITTERS SUMMARY…

- - - - Simple reflex actions
      - Transmission of information to&from brain&spinal cord
    - - Control of response and behaviour
        
        Forebrain, midbrain, hindbrain
  - - - Efferent nerves
      - Afferent nerves
    - - Sympathetic NS
      - Parasympathetic NS
  - - - Interneuron
      - Motor Neuron
      - Inside the neuron
        
        Glial (glue) cells
        
        Non-neural - maintain homeostasis (internal environment)
        
        For cortical development & they guide neurons
        
        Astrocytes(star) - largest, form BBB
        
        Microglia(mobile) - immune system - remove debris
        
        Myelin (outside of axon) formation
        
        Oligodendrytes - CNS
        
        Schwann - PNS
        
        Look at diagram for Myelin Sheath
        
        Myelin Sheath
      - Sensory Neuron
    - - Axon to dendrite
        
        Axodendritic exchange
      - Axon to cell body
        
        Axosomatic(body) exchange
      - Axon to axon
        
        Axoaxonic exchange
      - Dendrite to dendrite
        
        Dendrodendritic exchange
      - Resting potential = -70mv
      - Sodium-potassium pump
        
        Active process -Na+ out & K+ in
        
        3 Na+ out for every 2 K+ in
        
        Uses ATP
      - Action potential
        
        Transmits info
        
        All or nothing principle
      - Repolarization & refractory period
        
        Absolute refractory period
        
        Neuron is resistant to more stimulation
        
        Relative refractory period
        
        Neruon can be stimulated, but impulse has to be greater intensity than normal
        
        Repolarization
        
        resting potential back to -70mV
      - Saltatory conduction
        
        Myelin sheaths insulate axon segments
        
        Myelin Sheath
        
        Spaces between segments = nodes of ranvier
        
        Action potentials jump along axons at nodes - saltatory(jump) conduction
        
        Disorder of myelin = Multiple Sclerosis
      - Synaptic Transmission
        
        Action potential -> presynaptic terminal -> Ca++ ion channels open
        
        Open Ca++ ion channels cause vesicles to move & bind to presynaptic membrane
        
        Neurotransmitter diffuses across synaptic cleft
        
        They attach to receptor sites on postsynaptic membrane
      - Summation effects
        
        Additive effects of events occurring at the same time from different places on the neuron
      - Non-synaptic chemical communication
        
        Neuromodulators
        
        Widespread effect (compared to neurotransmitters)
        
        Usually peptides
        
        Hormones
        
        Chemicals released by endocrine system & effect target cells/organs
        
        eg. testosterone - aggression
  - - - Secrete hormones-
      - they influence metabolism
      - and body's response to stress
    - - Activates & controls part of NS that controls involuntary body functions
      - regulates sleep
      - stimulates appetite
    - - Ovaries - secrete hormones - female characteristics
      - tTesties - secrete hormones - male characteristics
    - - Secretes insulin - controls use of glucose
    - - Secrete hormone that maintains calcium level in blood
    - - For sleep cycles and biological cycles
    - - Number of hormones that influence other endocrine glands
    - - Immune system
    - - Hormones that stimulate heat production, bone growth, metabolism
  - - - Ionotrpic receptors (channel-linked)
        
        Ligand-gated ion channels
        
        Action is immediate and brief
      - Metabotropic (G protein-linked)
        
        Indirect, slow, complex, prolonged, widespread
    - - Neurotransmitter binds to channel-linked receptor and opens ion channels. Promotes rapid responses, eg ACh and amino acids
    - - Neurotransmitter binds to a G protein-linked receptor and acts through and intracellular second messenger. Promotes long-lasting effects, eg, biogenic amines, neuropeptides and soluble gases
    - - Main inhibitory neurotransmitter
        
        From glutamate via glutamate decarboxylase
        
        GABA's activity ends with re-uptake
        
        Dysfunction can cause seizures
    - - Inhibitory neurotransmitter
        
        Mainly in spinal cord, brain stem and retina
        
        Simple amino acid
        
        Formed from amino group + carboxyl group attached to carbon atom
        
        One glycine antagonist is strychnine
    - - Most common excitatory neurotrasnmitter
        
        NMDA glutamate is a subtype
        
        The amygdala and basal ganglia also contain high concentration of NMDA receptors
        
        NMDA receptors have a role in LTP
    - - Excitatory, stimulates NMDA receptors
        
        Opens ion channels, mainly in ventral spinal cord
        
        Inactivated when reabsored
    - - Aka 5-hydroxytryptamine (5HT)
        
        Serotonin synthesised via AA tryptophan
        
        Important role in CNS regulating emotions
        
        Pathways all over brainstem, cerebral cortex & spinal cord
        
        Stopped by reuptake of 5-HT
        
        SSRIS and TCAs used for depression
    - - Derived from melatonin within pineal gland and retina
        
        Role in sleep/wake cycle
        
        Also an inhibitor of the synthesis and secretion of dopamine and GABA
    - - Excitatory
        
        Found in locus coeruleus, pons and reticular formation
        
        Thought to play a key role in attention and arousal
    - - Monoamine neurotransmitters
        
        4 pathways: nigrostriatal, mesocorticolimbic, mesocortical and the tuberoinfundibular
        
        Shortage of cells that make dopamine in substantia nigra can lead to Parkinson's
        
        Excessive dopamine may be involved in schizophrenia
    - - First NT to be identified
        
        ACh present in peripheral and central NS
        
        Cholinergic pathways play role in cognitive functions, especially memory
        
        Alzheimer's patients have ACh deficiency in brain
        
        2 primary kinds of ACh receptors:
        
        Nicotinic ACh receptors (nAChR)
        
        Muscarinic ACh receptors (mAChR)
    - - Short amino acid chains, act as neurotransmitters
    - - Don't directly excite/inhibit postsynaptic cell, but increase/decrease the release of neurotransmitter or modify reaction of postsynaptic cells
    - - Some soluble gases can also act as neurotransmitters
        
        Nitric Oxide (NO) - produced by many cells - thought to play role in memory and learning
    - - Large Molecule
        
        Endogenous Opoids
        
        Substance P
        
        Oxytocin
        
        Antiduretic Hormone
        
        Chlolecystokin
      - Soluable gases
        
        Nitric Oxide
        
        Carbon monoxide
      - Acetylcholine
      - Small Molecule
        
        Monoamines
        
        Catecholamines
        
        Dopamine
        
        Adrenalin
        
        Anoradrenaline
        
        Indoamines
        
        Serotonin
        
        Melatonin
        
        Amino Acids
        
        GABA
        
        Glycine
        
        Glutamate
        
        Aspartate
  - - - Spinal cord
      - Brain
        
        Midbrain
        
        Hindbrain
        
        Forebrain
    - - Somantic NS
        
        Efferent Nerves
        
        Afferent Nerves
      - Autonomic NS
      - Sympathetic NS
      - Parasympathetic NS
  - - - Anatomical terms:
        
        Ventral: literally stomach but means bottom
        
        Medial - middle
        
        Lateral - away from middle (sides)
        
        Anterior - towards front (eyes, nose)
        
        Posterior - towards back
        
        Dorsal: literally back but means top
      - Planes of section:
        
        Transverse
        
        Sagittal
        
        Horizontal
      - Major divisions:
        
        Midbrain
        
        Tectum
        
        Superior colliculi
        
        Visual
        
        Inferior colliculi
        
        auditory
        
        Tegmentum
        
        Periaqueductal gray - pain and defensive behaviour
        
        Red nucleus - motor
        
        Reticular formation - arousal
        
        Substantia nigra - motor - Parkinson's
        
        Hindbrain
        
        Myelencephalon
        
        Medulla oblongata
        
        respiration, muscle tone
        
        Metencephalon
        
        Cerebellum
        
        Smooth muscle action
        
        Pons
        
        Sleep and arousal
        
        Forebrain
        
        Diencephalon
        
        Thalamus
        
        One in each hemisphere
        
        Contains sensory relay
        
        Hypothalamus
        
        ANS control
        
        Homeostasis
        
        Fighting, feeding, fleeing, fucking
        
        Telencephalon
        
        Striatum
        
        Caudate
        
        Putamen
        
        Globas pallidus
        
        Function
        
        Motor
        
        Cognitive - attention?
        
        Limbic system
        
        poorly defined
        
        Hippocampus & mammillary bodies
        
        memory
        
        Amygdala
        
        Emotion anxiety/fear
        
        Neocortex
        
        White matter
        
        Fibre tracts
        
        Grey matter
        
        Cortex
        
        cell bodies
        
        Gyri (humps)
        
        Sulci (valleys)
        
        Fissures (big valleys)
      - Six layer cortex
        
        Molecular layer
        
        External granular layer
        
        External pyramidal layer
        
        Internal granular layer
        
        Internal pyramidal layer
        
        Multiform layer
      - Lobes:
        
        Occipital
        
        Posterior end of cortex
        
        Receives input from visual pathways
        
        Most posterior part is primary visual cortex/striate cortex
        
        Damage to that causes loss of vision (cortical blindness)
        
        Extrastriate areas are distinct, colour processing and motion perception
        
        Parietal
        
        Between occipital lobe and central sulcus
        
        Deals with spatial awareness and navigation
        
        When there's injury, esp. right side, can experience hemispatial neglect
        
        Temporal
        
        Lateral on each hemipsphere under lateral fissure
        
        Left temporal lobe for human speech
        
        Also contributes to complex aspects of vision eg face perception
        
        also contributes to motivation and emotional behaviours
        
        Frontal
        
        Anterior to parietal lobe and dorsal to temporal
        
        Processes like planning, coordinating, controlling and carrying out behaviour
        
        Primary frontal cortex is in frontal love, responsible for control of voluntary movements
        
        Left frontal lobe is Broca's areas
        
        Prefrontal cortex receives info from all sensory systems
        
        Ventricular system
        
        Hollow structures in brain joined to spinal cord's central canal
        
        4 ventricles:
        
        Right & left
        
        Third
        
        Fourth
      - NEUROANATOMY SUMMARY
        
        Structure
        
        Forebrain
        
        Telencephalon
        
        Limbic system
        
        Basal Ganglia
        
        Cerebral cortex
        
        Six layer structure
        
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        Frontal Love
        
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        Occipital lobe
        
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        Temporal lobe
        
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        Parietal lobe
        
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        Diencephalon
        
        Thalamus
        
        Hypothalamus
        
        Pituitary gland
        
        Midbrain
        
        Mesencephalon
        
        Tegmentum
        
        Red nucleus
        
        Substantia nigra
        
        Reticular formation
        
        Tectum
        
        Inferior Colliculus
        
        Superior Colliculus
        
        Hindbrain
        
        Metencephalon
        
        Cerebellum
        
        Pons
        
        Raphe system
        
        Myencephalon
        
        Medulla oblongata
    - - How do you study a brain?
        
        Ex-vivo
        
        Post-mortem
        
        Non-dynamic
        
        Macroscopic and microscopic observation of tissue
        
        Staining tissue to show structures
        
        Biochemical analysis of tissue
        
        Ex-vitro
        
        Slices, cultures
        
        In-vivo
        
        Whole animal
        
        animal studies:
        
        Induced lesion
        
        Aspiration
        
        Electrical
        
        Chemical
        
        Give cognitive task to animal, damage a part of it's brain, can it still perform task? If no, area must play role in cognitive operation
        
        An example:
        
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        Stereotaxic surgery
        
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        Stimulation
        
        Electrical
        
        Chemical
        
        Micro recording
        
        Single-unit
        
        Multi-unit
        
        Genetic engineering
        
        Knockouts
        
        Replacement
        
        Invasive
        
        Non-invasive
        
        Biochemical analysis of dynamic processes
        
        Electrophysiology recording of neural activity
        
        Effects of drugs, changed chemical environment, electrical stimulation
        
        EEG and ERP
        
        Electroencephalography (EEG)
        
        Electrical field of brain
        
        Records potential of neurons doing same thing at same time
        
        Event-related potential (ERP)
        
        Changes in electrical fields related to a stimulus or action
        
        Averages EEG signal
        
        Inverse problem with localisation bc of unknowns in brain structure
        
        Magnetoencephalogram (MEG)
        
        There's a magnetic field perpendicular to electric field
        
        Magnetic field not attenuated by skull
        
        Very small magnetic fields
        
        Inverse problem reduced
        
        CT/CAT scan
        
        Computed Axial Tomography
        
        Fancy x-ray with computer reconstruction
        
        Requires radiation exposure
        
        Structural MRI
        
        Magnetic Resonance Imaging
        
        Detect hydrogen density
        
        Hydrogen density independent upon water content
        
        different tissues have different water content
        
        MRI provides near-photographic detail with no radiation
        
        Functional MRI (fMRI)
        
        Oxygen & glucose carried in blood
        
        Parts of brain that are active require more fuel
        
        Measures changes in blood flow - 'hemodynamic'
        
        Positron Emission Tomography (PET)
        
        Radioactive tracer
        
        Metabolic activity measured
        
        Transcranial Magnetic Stimulation (TMS)
        
        A magnetic field induces electrical current in a nearby conductor
        
        A magnetic pulse in a coil induces breif electrical current in nearby brain area
        
        Transiently disrupts functioning in the brain area
        
        Cerebral dialysis
        
        Measures concerntration of neurochemicals outside cells in behaving animals
        
        Fine microdyalysis probe consists of a metal tube with artificial semi-permeable membrane at the bottom
        
        2-deoxyglucose method
        
        Animal injected with radioactive 2-deoxyglucose
        
        Placed in situation that will activate a behaviour
        
        Slices of brain are then examined at post-mortem under autoradiography
        
        In-vivo voltammetry
        
        Measurement of the extracellular concentration of neurochemicals in behaving animals
        
        monitor changes in flow of current as the voltage across carbon-based electrode rises
        
        There are chemicals in the nervous system that oxidise at different intensities and are thus identifiable
        
        Behavioural genetic techniques
        
        Study of influence of heredity and environment
        
        Nature vs nurture
        
        Twin studies
        
        Adoption studies
        
        Neuropsychological techniques
        
        Measurement of psychological function in particular brain structure or pathway
        
        Psychometric theory - comparison against norms from large population
        
        Used in rehab and assessment
        
        Cognitive function such as attention, executive function, working memory
        
        RESEARCH TECHNIQUES SUMMARY
        
        Brain
        
        Research techniques
        
        Structural imaging
        
        CT scan
        
        MRI
        
        Functional imaging techniques
        
        PET
        
        fMRI
        
        TMS
        
        Electrical recording
        
        ERP
        
        EEG
        
        MEG
        
        Lesion techniques
        
        Electrolytic techniques
        
        chemical techniques
        
        Temoorary lesions
        
        Pharmacological manipulations
        
        Neurochemical techniques
        
        Cerebral dialysis
        
        2-deoxyglucose method
        
        In Vivo Voltammetry
        
        Behavioural Genetic techniques
        
        Twin studies
        
        Adoption studies
        
        Neuropsychological techniques
        
        Clinical neuropsychology