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Revision supervisions
Neurobiology
Sanjay Manohar
Gonville and Caius College, University of Cambridge 2001
http://www.smanohar.com
Neural induction
• noggin + chordin
– dorsalisation of mesoderm
• follistatin
– activin antagonist, also dorsalises
• all inhibit BMP-4 (which is in TGF-b family)
What have studies of lesions in the human
brain taught us about its normal function?
Intro: context of other methods eg. animals, imaging, anat+dev
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Frontal
– Kluver-Bucy, Phineas Gage,
UMN, apraxia, dementia, Broca
aphasia
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Parietal
– Balint, motion blindness, patient
DF, Wernicke aphasia, acalculia
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Occipital
– blindsight
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Temporal
– anomia, agnosia, alexia,
prosopagnosia, achromatopsia,
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Basal ganglia
– Parkinson's, Huntington's
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Cerebellum
– ataxia
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Medulla
– brain stem death!
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Hippocampus
– amnesia
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Other
– hypothalamus, thalamus
Conclusion: limitations of lesions (ethics, control, approximation etc.)
Short notes
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Write short notes on the electrical time constant of a membrane.
What controls the survival of newly generated nerve cells?
How do cells in the ventral spinal cord respond to differing levels of Shh?
The genomic sequence of the “AMPA” receptor encodes a Ca2+ channel but most AMPA receptors
are only permeable to Na+. Explain.
Describe briefly the optical factors that affect visual acuity.
Write short notes on two of the following: visual agnosia; the pupil; bleaching adaptation.
What kinds of neurotransmitters and neuropeptides occur in the central nervous system?
What is the function of lateral inhibition?
What purposes may be served by altering the sensitivity of auditory receptors?
How do the response properties of neurons differ between the retina and the primary visual cortex?
Write a concise account of any two of the following: colour vision; visual acuity; dark adaptation.
Describe the response properties of cortical neurones responding to visual stimuli.
What is the evidence for columnar organisation in the cerebral cortex?
Describe how the phenotypes of Dros. mutants illustrate the properties of neurogenic & proneural
gene products.
Contrast the inactivation of adrenergic and cholinergic signalling.
How are gaze-fixing eye movements controlled?
Draw an annotated diagram explaining how the stretch reflex might operate as part of a servo control
system.
Describe the somatosensory pathways in the mammalian central nervous system.
What are the principal differences between control of eye movements and limb movements?
The fly employs a number of different sensory mechanisms to keep its eyes aligned with the external
horizon irrespective body orientation. What might be the advantages of using more than one sensory
mechanism?
Acetylcholine receptors cluster at the synaptic site in response to an innervating motor axon. Outline
the mechanisms that contribute to this phenomenon.
Explain the function of activity-dependent synaptic facilitation in Aplysia.
What is the "lateral hypothalamic" syndrome?
Provide a schematic diagram illustrating the major connections of the hypothalamus.
Sample short questions
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Write short notes on the electrical time constant of a membrane.
Describe briefly the optical factors that affect visual acuity.
Write short notes on two of the following: visual agnosia; the pupil; bleaching
adaptation.
What kinds of neurotransmitters and neuropeptides occur in the central nervous
system?
What is the function of lateral inhibition?
What purposes may be served by altering the sensitivity of auditory receptors?
How do the response properties of neurons differ between the retina and the primary
visual cortex?
Write a concise account of any two of the following: colour vision; visual acuity; dark
adaptation.
Describe the response properties of cortical neurones responding to visual stimuli.
Contrast the inactivation of adrenergic and cholinergic signalling.
How are gaze-fixing eye movements controlled?
Draw an annotated diagram explaining how the stretch reflex might operate as part of
a servo control system.
Describe the somatosensory pathways in the mammalian central nervous system.
What are the principal differences between control of eye movements and limb
movements?
How has the eye resolved the problem of needing transparency to let
the light to the rods and cones but also need supply of O2 + nutrients
from blood vessels which absorb the light?
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Structure of cornea: 75% water
Structure of vitreous
– Acellular; lining: Hyalocytes of Balazs
– 98% water
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Lens structure
– Lamellae of anucleate lens cells
– Densely packed crystallins
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Circulation of aqueous humour
– ciliary body - angle - canal of Schlemm - scleral veins
– nourish cornea and lens
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Structure of retina
– inner half vascular: plexiform layers contain vessels
– outer half avascular: diffusion of nutrients through RPE
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Adaptation
– Completely stationary objects fade
– Experiment with corneal glue! and pentorch