chemical control of brain & behaviour Flashcards
what are the forms of communication?
1) direct synaptic transmission
2) diffuse modulatory systems
3) neuroendocrine signaling
4) autonomic nervous system networks
what do the diffuse modulatory systems do?
coordinate activation of groups of neurons in broad brain regions
where does DMS originate from?
what does DMS activate?
- core neurons (small set, only several thousand)
- originate from brainstem nuclei
- activate CNS metabrotropic receptors
- synapse NT release, but also NT release into extracellular fluid
what does the noradrenergic system origin?
locus coeruleus
noradrenergic system projections?
cortex, thalamus, cerebellum
noradrenergic system purpose? 6
- attention
- arousal
- sleep wake cylce
- attentive tasks
responds to most new, unexpected stimuli
increases neuron responsiveness
serotonergic system origin?
raphe nuclei
serotonergic system projections?
forebrain
serotonergic system purpose? 3
acts as locus with NE system
- modulates sleep/wake cycle
- fires more during wakefulness
- fires least during sleep
mood control
- selective seretonin reuptake inhibitors combat depression
activates and deactivates forebrain
dopaminergic (substantia nigra) system origin?
substantia nigra
dopaminergic (substantia nigra) projections?
projects to the striatum (caudate and putamen)
dopaminergic (substantia nigra) purpose?
voluntary movement initiation
dopaminergic (mesocorticolimbic) origin?
ventral tegmental area
dopaminergic (mesocorticolimbic) projections?
- frontal cortex
- limbic system
dopaminergic (mesocorticolimbic) purpose?
reward system that reinforces behaviours
basal cholinergic system origin?
telencephalon
basal cholinergic system projections?
- basal nucleus of mynert -> neocortex
- medial septal nuclei -> hippocampus
basal cholinergic system function?
- learning and memory
- coordinate activity in large brain areas
- first area that degenerates with alzeheimers
ponto cholinergic system origin?
- pons
- tegmentum
ponto cholinergic system projections?
- thalamus
- telencephalon
ponto cholinergic system purpose?
- dorsal thalamus: regulate excitability of sensory relay nuclei
- telencephalon: ACh link between brainstem and basal forebrain complex
- ANS: neuromuscular junction
what are stimulants that effect the diffuse modulatory system?
cocaine and meth
what do cocaine and meth do?
cocaine
- blocks DA reuptake
meth
- blocks catecholamine reuptake, stimulates DA release
what is the effect of NE/DA reuptake being blocked?
emotional
- increases alertness and self-confidence, euphoria, decreased appetite, exhilaration
physical
- mimic sympathetic activation: increase heart rate and blood pressure, pupil dilation
what does the neuroendocrine system do?
cells in the periventricular hypothalamus coordinate neuroendocrine signaling
- communicates w/ body
- helps regulate ANS outflow and circadian rythyms
- contains neurosecretory neurons that send axons to the pitutary for hormone signaling
helos maintain homeostasis
- integrates different signals to drive behaviour
- signals (hormones, somatic, etc)
what does the neuroendocrine system connect to?
pituitary gland
what does the neuroendocrine contain?
- posterior pituitary
- anterior pituitary
- hypothalamus-pituitary adrenal axis/HPA axis
- HPA axis and the Hippocampus
what differentiates prairie voles from montane voles?
prairie voles - monogamus
- have oxytocin and vasopressin receptors, in the brains reward areas
montane voles - polygamous
- become monagomus when injected with oxytocin and vasopressin
how is the anterior pituitary different from the posterior pituitary?
posterior does not release hormones directly in the blood stream, amplifies signal for other cells to do that
what does the anterior pituitary do?
involved with the release of other hormones
what does the HPA axis do?
mediator of stress response, involves the anterior pituitary hormone cortisol
what does the feedback loop in the HPA axis do?
negative feedback loop
- inhibits CRH and ACTH release
what are the negative effects of chronic stress?
baboons low in the social heirarchy have higher stress which leads to higher cortisol without regulation
higher cortisol can lead to
- hypertension, ulcers, depression
what is the function of the autonomic nervous system?
commands every non-skeletal muscle
- smooth muscle
- cardiac
- gland
how does the ANS differ from somatic motor control?
somatic motor control is monosynaptic
ans is disynaptic
describe sANS
- where are its pre-synaptic fiber located?
- where do the fibers originate?
sympathetic : fight or flight
- presynaptic fibers synapse in ganglia close to spinal cord
- originate in thoracic and lumbar segments
describe pANS
- where are the presynaptic fibers located?
- where do they originate?
parasympathetic: rest and digest
- presynaptic fibers synapse in ganglia closer to target tissue
- originate in brainstem and sacral segment
what does the enteric division do?
functions relatively independently in the gastrointestinal system, works w/ viscera
where does the enteric division get its input?
what is it made up of?
- gets some input from ANS
- made up of neurons that line the gut
at do enterochromaffin cells do?
communicate gut info to the brain
- the gut has taste receptors similar to the toungt
