pathophysiology - positive symptoms of schizophrenia
‘hyperdopaminergic’ state in the mesolimbic pathways
pathophysiology - negative symptoms of schizophrenia
‘hypodopaminergic’ state in the mesocortical pathways
define pain?
“ an unpleasant sensory or emotional experience associated with potential or actual tissue damage”
Pain sensation can be sub-divided into which two processes:
- Nociception
2. Perception
Detection: nociception?
involves detection by transducers (nociceptors) located on the terminals of specialised primary sensory nerve fibres.
Perception?
he activation of second-order sensory fibres that relay signals to higher cortical centres
pain mediators?
- TRPV channels: cation channels activated by numerous extracellular substances & intracellular mediators
- Bradykinin B2 receptors: these cause pain by PKC-mediated activation of TRPV channels
- μ-opioid receptors: during inflammation – opioid receptors transported to nerve terminals & recruited immune cells secrete endogenous opioid peptides.
Pain - spinal mediators?
Peripheral nociceptors terminate on the dorsal horn of spinal chord.
Tachykinin peptides released from primary afferent nerve ending - act on neurokinin receptors .
Opoid receptors - activated bt opoids from interneurones and descending pathways
Pain - central mediators?
secondary fibres in spinothalamic tract terminate in thalamus.
These nerve endings release glutamate - activate post-synaptic glutamate receptors
define Epilepsy?
sudden changes in behaviour caused by electrical hypersynchronisation of neuronal networks in the cerebral cortex”.
General seizures - Tonic-clonic seizures?
loss of consciousness → muscle stiffening → jerking/twitching → deep sleep → wakes up
Tonic/atonic seizures?
sudden muscle stiffening/sudden loss of muscle control
Myoclonic seizures
sudden, brief muscle contractions
