brain and disease Flashcards
dopamine
inhibitory neurotransmitter produced in the cells of the substantial nigra
the revised dopamine hypothesis of schizophrenia
abnormalities in dopamine with the mesolimib system and prefrontal brain regions are present in SZ
increased subcortical release of dopamine stimulates the D2 paths (positive symptoms) and reduced D1 paths are linked with the negative symptoms
neuroloigcal (organic) assessments in patients
state of consciousness mental state, attitutude insight cognitive funciton gait coordiination fine movements cranial nerves motor system (wasting, tremor, power, tone, reflexes) sensory system (vibration, touch, pain , 2 point dissemination)
psychiatric assesment
appearsenace general behaviour
mood and affect
speech-disorders of thought (Stream, form, content)
abnormal beliefs (E.g. delusions) and perception (e.g. hallucinations)
cognitive state (concentration, confusion, memory)
parkinsons disease
symptoms
decrease in spontaneous movement
gait diff
posture rigid tremor
degeneration of the pigmented neurones in the substantia nigra resulting in lower dopamine
1-2% incidnece
freq increase above 60
mortality between 45 and 100=7%
men and women equally affects
higher incidence in developed countries
two pathways int he basal ganglia
direct
and
indirect
direct pathway in BG
outflow from the striatum directly inhibits Globus plaids internus and substantial reticulate (SNr)
striatal neurons containing D1 receptors constitute the direct pathway and project to the GPi/SNr
indirect pathway in BG
comprises inhibitry connections between the striatum and the globus pallidus externus and between here and the sub thalamic nucleus.
striatal neurons containing D2 receptors are part of the indirect pathway and project to the globus pallidus externus
in parkinson’s the increased…..
inhibition of the thalamocortical pathway suppresses movement
parkinson’s accumulations of
a protein called alpha-synuclein into inclusions called lewy bodies in neurones
(and insuffient formation and activity of dopamine produced in retains neurones in parts of midlbrain )
deep brain stimulation where and hz
sub thalamic nucleus most effective site
frequencies of higher than 60Hz effectively alleviate symptoms freq smaller than 30Hz exacerbate sumps
deep brain stimulation hypothesis
stimulation prevents low frequency rhythm generation and desynchronises the extrastriastal basal ganglia and cortex
21st century treatments for parkinson’s disease
1)protection: Ca voltage channels blockers (SN cells have high energy calcium burden?)
glial derived neurotrophic factor Amgen
over stimulation of these channels - causes high electrical burden. By inhibiting the channel reduces the burden and reduces dopamine
(only about 30 years of this treatment)
2) Regeneration: transplantation, stem cells (induced, embryonic)
stem cells into brain cause probs e.g. tube formation
3) stimulation: smart stimulators optogenetics
Huntington’s disease symptoms
progressive
hyper/dyskinesias followed by akinesia and dystonia and dementia/psychoses
huntington’s pathology
striato- globus pallidus externa neurons die first, followed by stratio-globus pallidus interna and then more widepsread neurodegeneatrion (causing dementia/psychosis)
associated with nucear and cytoplasmic inclusions containing mutant huntintin and other proteins
