neuro disorders 2 Flashcards
mechanism of generalized absence epilepsy
circuits between thalamus and cortex, T neuron excites C neuron but is dependent on T-Ca channel.
drug that strengthens GABA inhibition
benzodiazapine
responsible for emotional valence to pain sensation
limbic system
Three sensory fibers of cutaneous nerve
AB - light touch
AS - rapid conduction of Pain
C- - slow conduction of pain
AB and AS cutaneous fibers use what transmitter?
Glutamate
C- pain fibers use what transmitters?
Glutamate and substance P
Region of the midbrain that is partly mediated by opioids (mainly Enkephalin)
Periaqueductal gray region (PAG)
principal site for synthesis of NE
locus ceruleus
How is pain blunted endogenously?
Descending pathway - PAG neurons, NE, and Serotonin project from brain to spinal cord dorsal horn
How does enkephalin inhibit pain transmission
binds to presynaptic receptors and reduces release of glutamate and substance P from nocioceptors.
How do serotonin and NE inhibit pain transmission?
directly inhibits spinothalamic neuron
dorsal horn neurons become sensitized by glutamate and substance P.
Central Sensitization resulting in allodynia
Nociceptive terminals become sensitized by prostaglandins, bradykinin, substance p developing lowered thresholds for activation
Peripheral sensitization resulting in hyperalgesia
Abnormal firing of nociceptive fibers in the absence of any stimulation
Neuropathic pain
Arm flexor rigidity
Leg extensor rigidity
Decorticate posture
TBI results in bilateral loss of motor cortex while sparing brain stem
Decorticate posture
TBI increases intracranial pressure causing loss of midbrain red nucleus function
Decerebrate posture
Arms and legs are rigidly held in extensor position
Decerebrate posture
lack of quality control over movements can promote fatigue in ______ disorders
cerebellar
patient presents with slurred speech, dysmetria, dysdiadochokinesia
cerebellar disorder
deficits of controlled movements, postural instability, ataxia
cerebellar disorder
Amygdala activity suppresses prefrontal modulation - activates brainstem amines DA and NE
fight or flight response
Bottom up behavior regulation
PFC subdivisions contribute to appraisal and reflective reactions to challenges and stressors
Top Down behavioral regulation
PFC subdivision: cognitive processing, memory, Executive function, decision making
Dorsolateral
PFC subdivision: Gut feelings, appetite, reward - social/emotion linked decisions
Orbitofrontal cortex
PFC subdivision: Connects with amygdala and brainstem, generates autonomic response to stress - part of “bottom-up” response to negative emotions
Medial PFC
