Chapter 15: Chemical Control of the Brain and Behavior Flashcards
() communication in sensory and motor systems need mechanisms that restrict synaptic transmission to synaptic cleft
point to point
describe the result of p2p connections in the nervous system
- release minute amt of NTs
- actions are brief and rapid responses
- tightly constrained
3 components of the NS that operate in expanded space and time
- secretory hypothalamus
- autonomic nervous system
- diffuse modulatory systems
main function of the hypothalamus
homeostasis
3 functional zones of the hypothalamus
- lateral
- medial
- periventricular
lateral and medial zones of hypothalamus have extensive connections with ()
brain stem and telencephalon
a group of cells in the periventricular zone constitutes the (), which lies above the optic chiasm and are involved in synchronization of circadian rhythms
suprachiasmatic nucleus (SCN)
how does the SCN regulate circadian rhythm
it receives direct retinal innervation and uses info from light dark cycle
other cells in the periventricular zone control the ANS and regulate outflow of ()
sympathetic and parasympathetic innervation of the visceral organs
the cells in a third group in the periventricular zone called () extend axons towards the stalk of the pituitary gland to secrete hormones
neurosecretory neurons
the posterior pituitary is technically part of the brain because it contains axons of () -> neurons that release chemicals into capillaries of posterior lobe
magnocellular neurosecretory cells
substances released into the blood by neurons
neurohormones
examples of neurohormones
oxytocin, vasopressin (ADH)
- “love hormone”
- promote social bonding
- stimulates lactation and uterine contraction
oxytocin
neurohormone that regulates blood volume and salt concentration
vasopressin (anti-diuretic hormone)
pipeline of angiotensin II production
low BP/BV -> kidneys release renin -> renin is converted to angiotensin I -> angio I breaks down to angio II
angiotensin II is also detected by the (), a part of the telencephalon that lacks BBB
subfornical organ
cells from the subfornical organs also activate hypothalamus in response to angio II -> induces (1) and (2)
- thirst, drinking behavior
- ADH release
“master gland”: anterior pituitary
“true master gland”: ()
hypothalamus
the anterior pituitary is under the control of () in the periventricular zone
parvocellular neurosecretory cells
parvocellular neurosecretory cells control the anterior pituitary by releasing (1) into (2) which then bind to specific receptors on anterior pituitary cells
- hypophysiotropic hormones
- hypo-thalamo-pituitary portal circulation
2 parts of the adrenal glands
- adrenal cortex
- adrenal medulla
the adrenal cortex produces () -> acts throughout the body to mobilize energy reserves and suppress immune system; stress hormone
cortisol
in response to detecting cortisol, parvocellular NCs release a peptide called (1), which travels to the anterior pituitary to stimulate the release of (2)
- corticotropin-releasing hormone
- corticotropin (ACTH)
how do blood cortisol levels self-regulate
cortisol reacts with specific receptors on the brain that lead to inhibition of CRH release
one feature of (Addison’s/Cushing’s) disease is adrenal insufficiency
Addison’s
Cushing’s disease is caused by () that results in elevated levels of ACTH and cortisol
pituitary gland dysfunction
explain an example of iatrogenic Cushing’s disease
excessive use of prednisone (cortisol medication)
preganglionic NT of sympathetic NS + parasympathetic NS
ACh
postganglionic NT of sympathetic NS
NE
postganglionic NT of parasympathetic NS
ACh
ACh/NE from postganglionic parasympathetic stimulation are detected by () ACh/adrenergic receptors
muscarinic
frenetically mobilizes the body for a for a short-term emergency at the expense of processes that keep it healthy over the long term (4 Fs)
sympathetic NS
works calmly for the long-term good (non-F processes)
parasympathetic NS
the “little” brain and its 2 networks
enteric NS; myenteric ad submucosal plexuses
the enteric NS is connected to the brain via the ()
vagus nerve, ANS
- integrates sensory info from internal organs and coordinates output to autonomic brain stem nuclei
- located in medulla and connected with the hypothalamus
nucleus of the solitary tract
ACh receptors that evoke a fast EPSP; found in NMJ and
nicotinic
metabotropic ACh receptors that lead to very slow EPSPs and IPSPs
muscarinic
examples of neuroactive peptides that are modulatory and serve to make postsynaptic neurons more sensitive to fast nicotinic effects
neuropeptide Y (NPY), vasoactive intestinal peptide (VIP)
postganglionic parasympathetic ACh has a very (widespread/localized) effect
localized
postganglionic sympathetic NE has a very (widespread/localized) effect
widespread
Preganglionic axons of the sympathetic division emerge only from the () of the spinal cord
middle third (thoracic and lumbar segments)
behaviors related to active sympathetic system
4 Fs: fight, flight, fright, fuck (sex)
processes controlled by parasympathetic NS
Non-F: digestion, growth, immune
responses, energy storage, etc.
activity of the () NS is required for the sexual reponse, esp in male
sympathetic
2 complicated networks of the Enteric NS
- myenteric, Auerbach’s: outside muscles
- submucosal, Meissner’s: inside muscles
central control of the ANS:
() in the HT sends axons to the brain stem and spinal cord nuclei that contain sympathetic and parasympathetic preganglionic neurons
periventricular zone
central control of the ANS:
() in the medulla is connected with the HT and autonomic brain stem nuclei; integrates sensory info from internal organs and coordinates output to autonomic brain stem nuclei
nucleus of the solitary tract
the 4 diffuse modulatory systems of the brain
- ACh basal forebrain and brain stem complexes
- NE locus coeruleus
- 5-HT raphe nuclei
- DA substantia nigra, ventral tegmental area (VTA)
common principles of the diffuse modulatory systems of the brain
- small set of neurons at the core
- neurons arise from brain stem
- one neuron influences many others
- synapses release NTs into extracellular fluid
Because of its widespread connections, the () can influence virtually all parts of the brain
locus coeruleus
the NE-ergic LC is activated in response to (1); least active during (2)
- new, unexpected, nonpainful sensory stimuli
- non-vigilant state
The locus coeruleus may participate in a () of the brain during interesting events in the outside world
general arousal, increase brain responsiveness
The general function of norepinephrine is to ()
mobilize the brain and body for action.
2 kinds of raphe nuclei projections
- caudal (medulla) - innervates SC, modulates pain signals
- rostral (pons and midbrain): innervates most of the brain
the 5-HT-ergic raphe nuclei and the NE-ergic system together comprise the ()
ascending reticular activating system
the ascending reticular activating system is particularly involved in ()
sleep-wake cycles, mood
serotonin release is most active during (1), least active during (2)
- wakefulness (aroused and active)
- sleep
DA-ergic system
- axons project to striatum
- facilitates initiation of voluntary movements
substantia nigra
DA-ergic system
innervates circumscribed region of the telencephalon
ventral tegmental area
the DA-ergic system in the VTA is also known as (1); it is particularly involved in (2)
- mesocorticolimbic dopamine system
- reward and value processing
the VTA is implicated in psychiatric disorders such as ()
schizophrenia, ADHD, addiction
2 components of the cholinergic diffuse modulatory system
- basal forebrain complex
- pontomesencephalotegmental complex
ACh system responsible for most of the neocortical cholinergic innervation
basal forebrain complex
the basal forebrain complex includes (1) and (2)
- medial septal nuclei -> HC
- basal nucleus of Meynert -> neocortex
ACh system
the () complex acts mostly on the dorsal thalamus, but also projects to the telencephalon -> functions to regulate excitability of thalamic sensory relay nuclei
pontomesencephalotegmental complex
() drugs act on CNS and interfere with chemical synaptic transmission
psychoactive (“mind-altering” compounds)
most psychoactive drugs act on () systems
diffuse modulatory
e.g. of depressants
alcohol, barbiturates
slow down brain function
e.g. of stimulants
cocaine, methamphetamine
speed up brain function
e.g. of halucinogens
LSD, ketamine
alters perception of reality
e.g. of opiates
morphine, heroin
induce euphoria
LSD is a strong agonist of () receptors to inhibit the action of these nuclei
raphe nuclei serotonergic
cocaine and amphetamine affect the () systems -> sympathomimetic (mimic endogenous versions of the NTs)
DA and NE
common action of stimulants is to block ()
catecholamine reuptake
cocaine targets (1) reuptake
amphetamine blocks (2) reuptake and stimulates (3) release
- DA
- NE and DA
- DA
why are stimulants like cocaine and meth addicting
they short-circuit the systems normally reinforcing adaptive behaviors