General Anatomy (some in autism deck) Flashcards
what is the amygdala involved in?
- emotional response to face recognition
- involved in reward and addiction
what is the reticular formation?
a diffuse ascending network regulating arousal
Where does the NAdr efferent pathways (tracts) originate from?
locus coeruleus
Where is the locus coeruleus located?
midbrain
What does the locus coeruleus play a role in?
its part of the reticular formation and has a role in the arousal, sleep/ wake cycle
what are the three main dopamine pathways?
- mesocortical pathway
- mesolimbic pathway
- nigrostriatal pathway
what role does the arcuate nucleus play in dopamine pathways?
sends a short projection into the median eminence, releasing dopamine which goes onto regulate the release of prolactin from the anterior pituitary
what are the three dopamine nuclei?
- substantia nigra
- ventral tegmental area
- arcuate nucleus of the hypothalamus
what are the two dopamine pathways and there roles?
nigostriatal : motor control
mesolimbic and mesocortical: behaviour
Where is the raphe nuclei located and what does it do?
In the medulla and is part of reticular formation. It acts by innervating the limbic system.
It has been shown that the level of neuronal activity increases immediately prior to and during periods of activity (in free moving animals).
what is the nucleus basalis of meynert involved in?
Cognitive formation and memory
what are the five methods for studying CNS disorders?
- imaging techniques
- indirect ‘markers’ for changes in neurotransmitter function
- post-mortem studies on human brain
- genetics - linkage analysis
- animal models
Name imaging techniques of the brain
- computerised tomography- CT
- MRI (magneticc resonance imaging)
- PET and SPECT
Name advantage and disadvantage of CT scans?
A: like an xray of the brain and can be useful to indicate structural changes
D: spatial resolution is only several mm so can’t tell you about any discrete changes
what does MRI depend on?
Different level of water content, in different regions of the brain as it gives you different resonance signal
Why is MRI better than CT?
Resolution is better (less than 1 mm)
what is the developmental MRI called and what is it based on?
Functional MRI (fMRI) and is based on the fact bthat oxyhemoglobin has different magnetic resonance to deoxyhemoglobin (can look at ratio between the two as depends on level of metabolic activity)
Name a problem with fMRI?
Does not tell you whether neurons are inhibitory or excitatory just shows which regions of the brain are activated
what can fMRI do?
It reveals patterns of activity in the intact brain
If an individual saw a visual stimulus what would an fMRI see?
The microvasculature responds by increasing blood flow, this increases the oxyhb to deoxyhb ratio
what does diffusion tensor imaging allow?
Allows tracking of fibre tracts in the brain, relying on the fact water molecules inside axons are much less mobile than in the extracellular fluid - relies on limited mobility of water
what is PET?
Positron Emission Tomography
what is SPECT?
Single photon Positron Emission Tomography
what is the main advantage of SPECT ?
Does NOT require on site cyclotron first unstable positron emission isotopes are created in cyclotron (eg. O (15) - half life of 2 min)
what two ways can SPECT be used for?
- isotopes are imjected they distribute according to the relative activity of the brain regions
- technique may be used to estimate receptor levels
Name two non-invasive techniques to study the brain?
- electroencephalography (EEG)
- magnetoencephalography (MEG)
Name the three places to look for metabolite levels as indirect markers for neurotransmitter functions
1) Cerebrospinal fluid
2) plasma
3) urine
disadvantages on post-mortem studies on brains
1) protein is labile - may degrade
2) patient may have been taking medication
(need to know drug history of patients)
what are RFLPs
Restriction-fragment length polymorphisms
what do RFLPs do?
they change where restriction endonucleases (enzymes) cleave DNA
When RFLPs are referred to as inherited in a Mendelian manner what does this mean?
it requires family ‘pedigree’ of inheritable disease - easiest to study in ‘genetically isolated’ communities
What disease did RFLP allow gene mutation mapping for?
Huntigdon’s chorea
whats a disadvantage of RFLPs?
less successful for other disorders - as these may involve multiple genes or mitochondrial DNA
whats an advantage and disadvantage of animal models mimicing neurochemical changes that occur in disease?
A: Drug screening therapy
D: not an exact ‘phenocopy’ of the disease
what does the medial forebrain bundle consist of?
dopaminergoic, noradrenergic and serotonergic projections
what is CRF
Cortoicotrophin releasing factor
(a neuropeptide)
where are mu opiate receptors expressed ?
GABA interneurons in the VTA
What do mu receptors do ?
- inhibit GABA release
- increase activity in the dopamine mesolimbic pathway
If LSD decreases 5-HT turnover in rat brain what is that evidence for?
LSD acts as a 5-HT2 receptor agonist
