Neuroanatomy Flashcards
What is the role of acetylcholine?
- Used by spinal cord to control muscles + neurones in brain to regulate memory
- Excitatory
What is the role of dopamine?
- Feelings of pleasure when released by brain reward system
- Multiple functions depending on where in brain it acts
- Inhibitory
What is the role of GABA?
Major inhibitory NT in brain
What is the role of glutamate?
Major excitatory NT in brain
What is the role of glycine?
- Used mainly by neurons in spinal cord
- Inhibitory
What is the role of norepinephrine?
- NT + hormone
- Part of fight or flight response in peripheral NS
- Acts as NT in brain
- Usually excitatory
What is the role of serotonin?
- Involved in mood, appetite + sensory perception
- In spinal cord, serotonin = inhibitory in pain pathways
What neuropsychiatric diseases are associated with acetylcholine?
Alzheimers
What neuropsychiatric diseases are associated with serotonin?
Depression Migraine Ageing ADD Anxiety
What neuropsychiatric diseases are associated with dopamine?
Increased in Schizophrenia
Decreased in Parkinsonism
What neuropsychiatric diseases are associated with GABA?
Epileptic seizures
What neuropsychiatric diseases are associated with glutamate?
Migraine
Stroke
Autism
What is grey matter made up of?
Cell bodies
What is white matter made up of?
Axons
White due to myelination
What does the forebrain (prosencephalon) divide into?
Telencephalon
Diencephalon
What does the midbrain (mesencephalon) divide into?
Mesencephalon
What does the hindbrain (rhombencephalon) divide into?
Metencephalon
Myelencephalon
What is the Telencephalon involved in?
- Olfactory lobes - smell
- Hippocampus - memory storage
- Cerebrum - association
What is the diencephalon involved in?
- Retina - vision
- Epithalamus - pineal gland
- Thalamus - relay centre for optic + auditory neurones
- Hypothalamus - temp, sleep + breathing reg
What is the mesencephalon involved in?
Midbrain - fiber tracts between anterior + posterior brain, optic lobes + tectum
What is the metencephalon involved in?
- Cerebellum - coordination of complex muscular movements
- Pons - fiber tracts between cerebrum + cerebellum
What is the myelencephalon involved in?
Medulla - reflex centre of involuntary activities
What is the cerebellum divided into?
- Flocculonodular lobe - regulates balance + co-ordination
- Posterior lobe
- Anterior lobe
What do the areas closes to the vermis regulate?
- Spinocerebellum/paleocerebellum
- Body + limb movements
What does the neocerebellum regulate?
Planning, sensory movements for action
Ataxic gait
Name some pontine disorders
- Locked in syndrome
- Central pontine myelinolysis
What can cause progressive supranuclear palsy?
- Supranuclear opthalmoplegia
- Neck dystonia
- Parkinsonism
- Pseudobulbar palsy
- Behavioural impairment
- Imbalance
- Frequent falls
What is the role of the reticular formation?
- Ascending/ descending through brainstem
- Included ARAS = role in arousal
- Serotonergic, Dopaminergic, Noradrenergic. Histaminergic, Cholinergic + Thalamic nuclei
What is the role of the tectum (mesencephalon)?
- Superior colliculus - visual processing + eye movement control
- Inferior colliculus - auditory processing
What is the tegmentum and what is its role?
- Floor of midbrain
- Homeostatic + reflexive pathways
- Motor inhibition from thalamus + basal nuclei
- Red nucleus = motor coordination
- Substantia nigra - reward co-ordination (via nigrostriatal pathway), movement control
- PAG - pain modulation (spinothalamic tract)
- Ventral tegmental area - mesocorticolimbic dopamine = reward circuit liked to nucleus accumbens
What changes take place in the mesencephalon in Parkinson’s?
Reduction in dopaminergic neurones in substantia nigra
What changes take place in the mesencephalon in Schizophrenia?
Increased dopamine in substantia nigra
What changes take place in the mesencephalon in multi system atrophy?
Degeneration of striatum and substantia nigra
What changes take place in the mesencephalon in ventral tegmental?
Primary sites of addictive drugs
What does the diencephalon contain?
- Thalamus
- Hypothalamus
- Pineal body
- Subthalamus
- Epithalamus
- Mamillary bodies
What is the role of the thalamus?
- Relay station for all sensory signals
- Lateral geniculate nucleus = visual
- Medial geniculate nucleus = auditory (pathway goes to inferior colliculus + auditory cortex
What is the role of the hypothalamus?
- Anterior - vasopressin, oxytocin, somatostatin, sweating + thermoreg
- Tuberal - BP, HR, satiety, GHRH
- Posterior - memory, BP, vasopressin, orexin
What is the role of the pineal body?
- Secretes melatnin
- Not isolated from BBB
Which part of the diencephalon is damages form thiamine deficiency?
Mammillary bodies
Wernicke-korsakoff
What is the limbic system?
- Connecting structures surrounding brainstem - cingulate gyrus, hippocampus, hypothalamus + anterior thalamic nuclei
- Enables cortical control of emotion + role in memory storage
What is included in the limbic system?
Telencephalon, diencephalon + mesencepahlon
What are the cortical areas of the limbic system and their functions?
- Limbic lobe
- Orbitofrontal cortex - involved in frontal lobe, decision making
- Pineform cortex - olfactory system
- Entorhinal cortex - memory
- Hippocampus - consolidation of new memories
- Fornix - white matter, connects hippocampus + other structures
What are the subcortical areas of the limbic system and their functions?
- Septal nuclei - pleasure zone
- Amygdala - emotional processes
- Nucleus accumbens - reward, pleasure, addiction
What are the diencephalic structures of the limbic system and their functions?
Hypothalamus
- centre limbic system
- connected with frontal lobes, septal nuclei + brainstem reticular formation via medial forebrain bundle
- connected with thalamus via mammillothalamic fasciculus
Mammillary bodies
- part of hypothalamus
- receives signals from hippocampus via fornix + projects to thalamus
Anterior nuclei of thalamus
- receive input from MB
- memory processing
Where is the Hippocampus and what is its role?
- Telencephalon
- Medial temporal lobe
- ST > LT memory
- Spatial memory
- Includes dentate gyrus - new episodic memories, contains granule cells
- Alzheimers + other dementias = hippocampal atrophy
What is the cortex?
- From telencephalon
- Memory, attention, cognition, awareness, thought, language + consciousness
- 7 layers, grey matter with underlying white matter
What are the parts of the frontal lobe and their functions?
- Superior frontal gyrus - self-awareness/laughter
- Middle frontal gyrus
- Inferior frontal gyrus - broca’s area (expressive aphasia)
- Paraolfactory area - limbic
- Medial frontal gyrus - executive mechanisms
- Orbitofrontal cortex = stimulus-reward, addiction
- Ventromedial prefrontal cortex - decision making, emotion regulation, addiction
What is the prefrontal cortex?
Planning + executing actions
What can lesions of the PFC produce?
- Dramatic changes in personality
- Loss of spontaneity/problems with initiating speech/movements
- Inability to make and carry out sequence of actions/plans
Give an example of a cortical-subcortical-cortical loop
- Dense reciprocal connections between PFC + parts of limbic system
- So any loss of connectivity from limbic system > cortical targets will affect normal function of that area
What is the main function of the parietal lobe?
Integrates sensory information
What is the dominant hemisphere of the parietal lobe involved in?
- Dysphasia, aphasia
- Dyscalculia
- Dyslexia
- Apraxia
- Agnosia
What is the non-dominant hemisphere of the parietal lobe involved in?
- Spatial disorientation
- Constructional apraxia
- Dressing apraxia
- Anosognosia
What is Gerstmann syndrome?
Dyscalculia
Dysgraphia
Finger agnosia
LR disorientation
What are the parts of the temporal lobe and their functions?
- Transverse temporal gyri (Heschl’s gyri) + Superior temporal gyrus = auditory cortex
- Posterior STG = Wernicke’s area
- Middle temporal gyrus
- Fusiform gyrus - facial recognition, synaesthesia, dyslexia, prosopagnosia
- Inferior temporal gyrus - visual object recognition
What are the parts of the occipital lobe and their functions?
- Lingual gyrus - vision + dreaming, word processing, limb integration + encoding complex images
- Cuneus - basic visual processing
- Calcarine sulcus/fissure - primary visual cortex - takes signal from later geniculate nucleus via thalamus
Where is the primary motor cortex?
Precental gyri
Where is the primary somatosensory cortex?
Postcentral gyri
What does the arcuate fasciculus do?
Links Broca’s area to Wernicke’s area
What does the uncinate fasciculus do?
- Links temporal inferior frontal gyrus + frontal lobe
- Links hippocampus + amygdala with orbitofrontal cortex
