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Week 2: Neuroanatomy - Coggle Diagram

- - - - Genetic variations give
        rise to various phenotypes
    - - Species with favourable traits more likely to survive and reproduce
    - - Offspring also have
        favourable traits
  - - - Forebrain, midbrain, hindbrain all present in ancestors
      - Different selection pressures lead to varying complexities of neural structures
      - Hindbrain :arrow_forward: Midbrain :arrow_forward: Forebrain
    - - Evolved from common ancestors
  - - - brain and spinal cord coordinate activity in the animal
        
        close proximity to
        major sensory organs
        
        protected by bone
        
        dorsal location
        easier to defend
      - Evolutionary
        Development
        
        :chart_with_upwards_trend: in size of cerebrum and cerebellum
        
        :chart_with_upwards_trend: in convolution or folding of the cortex
    - - ventral location is
        vulnerable
      - unprotected by
        spinal column
- - - - Cushions the brain
        from impact or pressure
        
        Neurons do not fire haphazardly (eg. seizures due to pressure from tumours)
      - Prevents neurons from responding to external pressure
    - - waste materials in CSF useful biomarker for medical conditions
        
        Spinal tap
        
        CSF obtained from lumbar region of spinal cord using a needle
  - - - caused by large volume of CSF due to ventricle blockages
      - hinders normal brain development which can cause intellectual disability
      - treated using shunt or surgery to enhance CSF drainage
      - diagnosed by Chun gun
    - - commonly associated
        with enlarged ventricles
- - - - supplies oxygenated blood to most of the brain
      - circular configuration minimises brain damage from blockage in a major artery
      - Origin of posterior
        cerebral arteries
  - - - Neurons highly vulnerable to oxygen deprivation :skull_and_crossbones: due to high metabolic rate
- - - - Microstructural
        Integrity
        
        Fractional
        Anisotropy
        
        Mean Diffusivity
        
        measured with
        diffusion MRI
    - - Association
        
        connects different areas
        in the same hemisphere
      - Commissural
        
        connects bilateral regions
        across both hemispheres
      - Projection
        
        connects cortical areas to
        subcortical areas and spine
    - - structure that curls upwards
        from the hippocampus
      - considered both
        commissural and
        associative
  - - - Cortical
        Thickness
        
        distance between cerebrospinal fluid
        and white matter
        
        studied by structural MRI
      - GM Volume
      - Brain Activity
        
        studied by functional MRI
  - - - sensory axons found in
        dorsal parts of spinal cord
      - motor axons found in ventral parts of spinal cord
    - - neurons in dorsal horns receive sensory input
      - neurons in ventral horns pass motor information to muscles
        
        involved in
        spinal reflexes
    - - complex reflexes that allow for rhythmic movement
        
        Shifting weight from
        one leg to the other
        
        hopping
    - - Lumbar damage
        
        loss in all four limbs
      - Cervical damage
        
        loss in lower torso
      - Loss of sensation and
        voluntary movement
      - Loss of control over bladder and bowel functions
        
        brain cannot voluntarily
        control sphincter muscles
- - - - Parietal
        
        somatosensory
        processing
        
        spatial navigation
        
        language
      - Temporal
        
        memory
        
        language
        
        sensory processing
        
        separated from frontal
        lobe by lateral sulcus
      - Occipital
        
        Visual Processing
        
        found at the back
        of the cortex
      - Frontal Lobe
        
        Functions
        
        higher-order
        cognition
        
        associated with more
        anterior brain sections
        
        Attention
        
        social functions like
        theory of mind
        
        separated from parietal lobe
        by the central sulcus
        
        Dorsolateral
        Prefrontal Cortex
        
        Functions
        
        Attention
        
        Working Memory
        
        Planning of
        behaviour
        
        top and side
        of frontal lobes
        
        Complications
        
        Apathy
        
        Personality changes
        
        Inability to plan
        
        Orbitofrontal
        Cortex
        
        Functions
        
        Impulse control
        
        Delayed gratification
        
        located above and
        behind the eyes
        
        Complications
        
        Emotional Disturbances
        
        Impulsitivity
        
        Extreme antisocial behaviour associated with reduced volume
        
        Lower activity
        
        Schizophrenia
        
        ADHD
        
        Broca Area
        
        speech production
        
        damage results in
        speech difficulties
      - six distinct layers numbered 1 to 6 from surface to centre
        
        Layer :one: has no cell bodies
        
        Layers :two: and :four:
        contain granule cells
        
        Layers :three: and :five: contain pyramidal cells
        
        Layer :six: has many cell types that merge into underlying white matter
      - Insula
        
        found in the
        lateral sulcus
  - - - Hypothalamus
        
        Functions
        
        Fleeing
        
        F$*%
        
        Fighting
        
        directs the automatic
        nervous system
        
        Feeding
        
        Regulated by the ventromedial nucleus of the hypothalamus (VMH)
      - Thalamus
        
        Functions
        
        receives input from sensory systems (except olfactory) and forwards it to cerebral cortex
        
        receives regulatory input from hypothalamus and other circuits
        
        coordinates information processing across different brain parts
      - Hippocampus
        
        learning, memory and stress
        
        Complications
        
        vulnerable to stress
        
        Anterograde
        Amnesia
        
        difficulty forming new long-term declarative memories
      - Amygdala
        
        associates stimuli with emotional meaning (positive / negative)
        
        responds to rewards
        
        receives sensory input through the thalamus and sends info to other limbic structures and cerebral cortex
        
        Complications
        
        abnormal emotional calmness
        
        inability to respond correctly to dangerous situations
        
        may underlie some symptoms of autism
    - - Striatum
        
        Putamen
        
        Nucleus
        Accumbens
        
        Caudate
      - Pallidum
      - reward processing and
        motivation regulation
      - Functions
        
        receives input from cortex and connects with motor areas in thalamus
        
        crucial for operant conditioning
      - Complications
        
        Movement disorders
        
        Hunington's
        
        Parkinson's
        
        Psychological
        disorders
        
        OCD
        
        ADHD
    - - Brain Stem
      - Cerebellum
      - Medulla
        
        contains large amounts
        of white matter
        
        most caudal region
      - Pons
        
        connects the medulla, higher brain centres and the cerebellum
        
        Cochlear Nucleus
        
        receives sound information
        
        Vestibular Nucleus
        
        receives information about head position and movement
  - - - processes
        sensory information
      - Found in occipital, temporal and parietal (OTP) lobes
        
        Primary visual cortex
        in occipital lobe
        
        Primary auditory cortex
        in temporal lobe
        
        Primary somatosensory cortex in postcentral gyrus
    - - highest level of control for voluntary motion
      - Primary motor cortex found in precentral gyrus (frontal lobe)
    - - found in frontal, temporal
        and parietal lobes
      - connect and integrate
        sensory and motor functions
- - - - found in the
        dura mater
      - provide space for CSF that carries toxins or foreign material to drain through
      - immune cells found in blood-filled sinuses detect antigens and initiate immune response
      - allow immune responses to occur on the margins of the brain to prevent adverse effects
  - - - contains CSF
      - separates arachnoid layer from pia mater
- - - - activated by external stimuli
        (detecting danger)
      - communicate with target organs through norepinephrine
    - - Heart-Rate
        Variability
        
        :chart_with_upwards_trend: variability indicates healthy balance of ANS
        
        :chart_with_downwards_trend: variability indicates sustained sympathetic activity
    - - transmit commands from the CNS to glands and organs
      - activated by internal stimuli
        (food in stomach)
      - communicate with target organs using acetylcholine
    - - emotion-related brain structures affect the hypothalamus and indirectly the ANS
    - - neurons embedded in the lining of the gastrointestinal system
      - Gut-Brain Axis
        
        two-way communication system between brain and ENS
    - - allows for a coordinated response to emergencies
      - series of ganglia just
        outside the spinal cord
  - - - 12 pairs of nerves that directly enter and exit the brain
    - - 31 pairs of nerves