Anatomy Forebrain Flashcards
What is the group of paired nuclei located in diencephalon that form the lateral walls of the 3rd ventricle?
Thalamus
The thalamus is subdivided by white matter into what groups?
Anterior, lateral, and medial groups
Thalamus functions to filter and process afferent input from what 3 things?
- Basal ganglia (VA, VL)
- Cerebellum (VL)
- All conscious sensory except olfaction
What part of thalamus do these sense travel to? Body somatosensory - Head somatosensory - Vision - Auditory - Taste - Balance -
Body somatosensory - VPL Head somatosensory - VPM Vision - lateral geniculate Auditory - medial geniculate Taste - VPM Balance - VPL?
Thalamus functions to send efferent output where?
Cerebral cortex
Thalamus is functionally divided into what 3 type of nuclei?
- Relay
- Association
- Nonspecific
Which nuclei connects the basal ganglia, cerebellum, and conscious sensory (except olfaction) to cerebral cortex?
What are the motor?
What are the sensory?
Relay thalamic nuclei
a) motor: VA, VL
b) sensory: VPM, VPL, medial geniculate, lateral geniculate
Which nuclei does sensory, memory and emotion (limbic function) integration?
Declarative memory -
Sensory integration -
Emotion -
Association nuclei
a) declarative memory: anterior nuc. lateral dorsal nuc. midline nuc.
b) sensory integration: lateral posterior, pulvimar
c) emotion: medial group
Which nuclei regulate consciousness, arousal, attention?
Nonspecific nuclei (modulate relay and associative nuclei)
- interlaminar nuc.
- reticular nuc.
How is the hypothalamus connected to the pituitary?
Infundibulum
hypothalamus nuclei:
preoptic nuclei -
circadian/endocrine/reproductive and temperature regulation
hypothalamus nuclei:
suprachiasmatic nucleus -
circadian rhythms
hypothalamus nuclei:
supraoptic nucleus
synthesize and release vasopressin (ADH) and oxytocin
hypothalamus nuclei:
paraventricular nucleus
also synthesize and release vasopressin (ADH) and oxytocin from posterior pituitary; ANS control center
hypothalamus nuclei:
arcuate nucleus
releasing factors to control anterior pituitary
hypothalamus nuclei:
ventromedial nucleus
releasing factors to control anterior pituitary, feeding/satiety, limbic rage behavior
hypothalamus nuclei:
dorsomedial nucleus -
also releasing factors to control anterior pituitary, feeding/satiety, limbic rage behavior
hypothalamus nuclei:
tuberal nuclei -
releasing factors to control anterior pituitary
hypothalamus nuclei:
mamillary bodies -
limbic
The visceral function of the hypothalamus is (conscious/unconscious)?
Unconscious (autonomic reflex)
Which nucleus is the reflex control center for viscerosensory afferent and autonomic motor efferent?
a) viscerosensory afferent for BP comes from where?
b) autonomic efferent for BP para and sympathetic travel through where?
Paraventricular nucleus a) afferent = solitary nucleus b) efferent = parasympathetic: dorsal motor nuc. sympathetic (ventrolateral medulla)
Endocrine:
Posterior pituitary hormones ADH and oxytocin come from which nucleus?
supraoptic and paraventricular nuc.
Endocrine:
Anterior pituitary hormone release is regulated by tropins from
- arcuate nuc.
- ventromedial nuc.
- dorsomedial nuc.
- tuberal nuc.
rhythmic endocrine control comes from which 2 nuclei?
- suprachiasmatic nuc.=circadian (time of year)
2. preoptic nuc.=diurnal (time of day – GH at night)
Thermoregulation of hypothalamus controlled by what nucleus?
preoptic nuc.
How does the heat loss center work in hypothalamus?
↑blood temp→hypothalamus thermosensory cells → cardiovascular & respiratory centers→vasodilation/perspiration & panting
How does heat conservation center work in hypothalamus?
↓blood temp→hypothalamus thermosensory cells → brainstem control centers →vasoconstriction, ↑CO, ↑metabolism, piloerection, shivering
Hypothalamus controls drinking through what nucleus?
paraventricular nucleus is thirst center
Hypothalamus controls eating through what 2 nuclei?
- dorsomedial
2. ventromedial nuc.
Feeing center of hypothalamus is governed by what aspects?
governed by olfaction, taste, and amygdala
satiety center=set point of hypothalamus is relative to what aspects?
relative to metabolic rate, previous caloric intake, current caloric intake
Sexual behavior is controlled by what nucleus of the hypothalamus?
What are female/male receptors?
Preoptic
a) ♀ hypothalamus has estrogen & progesterone receptors
b) ♂ hypothalamus has testosterone receptors
Behavioral emotion is controlled by what nuclei of the hypothalamus?
aggression/fight or flight
- dorsomedial
- ventromedial
- mamillary bodies
Sleep behavior is controlled by what nucleus of the hypothalamus?
Suprachiasmic
Memory behavior is controlled by what nuclei of the hypothalamus?
- dorsomedial
- ventromedial
- mamillary bodies
The other diencephalon:
Subthalamus has what nucleus?
What is it’s role?
subthalamic nucleus is a relay for basal ganglion mediated motor modulation
The other diencephalon:
Epithalamus has what complex that acts as a relay linking the limbic system/hypothalamus to midbrain (mesencephalon)?
habenular complex
The other diencephalon:
Epithalamus has the pineal gland which functions to do what? What hormones does it secrete?
a) day length (light) modulated hormone release
b) hormones include:
1. neurosecretions: NEpi, serotonin, and melatonin
2. hypothalamic releasing/inhibiting factors
What is the overall function of the basal ganglia (nucleus)?
overall function is psychomotor modification
The limbic system has structures in what part of the CNS?
Tel and diencephalon
What is the overall function of the limbic system?
overall function is to modulate:
1. hypothalamus (behavior, endocrine, autonomic …)
2. periaquiductal gray (autonomic, emotion, pain modulation)
to affect:
1. emotional behavior (emotionally charged response)
2. motivation
3. short term memory
The hippocampal formation of the limbic system includes what 3 parts?
- hippocampus
- dentate gyrus
- subicular cortex (parahypacampical gyrus)
The septal area of the limbic system includes what 3 parts?
- lateral septal nuclei
- medial septal nuclei
- diagonal band of Broca
T/F the amygdale, the prefrontal cortex, the cingulate gyrus, and substantia innominate are parts of the basal ganglia
False, they are all a part of the limbic system
The insula does what?
limbic integration with pain, olfaction, taste
What is the defining property of limbic structures?
they communicate with hypothalamus or periaquiductal gray to modulate the activity of these structures
The 3 specific functions of the hippocampal formation are:
- modulation of aggression & rage
- autonomic & endocrine = visceral
- learning and memory
What NT does the hippocampal formation use for long term memory?
via effects of glutamate on NMDA channels and gene transcription → increased synaptic strength→long term memory
The 3 specific functions of the septal area are:
- modulation of aggression & rage
- autonomic visceral
- drinking (with paraventricular nuclei)
The 4 specific functions of the amygdale are:
- aggression, rage
- feeding
- cardiovascular, endocrine visceral
- learning & memory
The 4 specific functions of the prefrontal cortex are:
- emotional and intellectual processes
- suppresses aggression & rage
- affects feeding
- visceral functions: BP, respiration, gastric motility, thermoregulation
The functions of the cingulate gyrus are similar to that of what?
function similar to prefrontal cortex
The specific function of the substantia innominata is what?
- relay between amygdala and hypothalamus
The substantia innominata contains the basal nucleus of Meynert which does what?
Basal nucleus of Meynert: a cholinergic efferent to cortex and other limbic structures
Afferent input to the limbic system comes from what 4 areas?
- special senses: olfaction, taste, vision, auditory
- reticular formation
- hypothalamus feedback connections
- thalamus
The special sense travel to the limbic system via what?
via entorhinal cortex
The reticular formation signals travel to the limbic system via what?
monoamine neuronal projections
T/F The Different parts of the limbic system are not connected
False, different parts of the limbic system are interconnected
Efferent output from the limbic system travels to what 4 general areas?
- thalamus
- hypothalamus
- cerebral cortex
- periaquiductal gray
When signals from the limbic system get to the hypothalamus, what 2 structures will they go to?
- mammillary bodies
2. medial hypothalamus
What is the reticular system?
- diffuse set of nuclei located in core of brainstem, from diencephalon to spinal cord
- synaptic connections with ascending and descending tracts, and CN nuclei
The reticular system will modulate what general type of activity?
- sensory
- motor
- autonomic activity
- behavioral
The more specific activity the reticular system modulates are:
- sleep/wake (RAS – reticular activating system = alarm clock)
- consciousness
- emotion
- refine motor signals
- pain modulation
The conscious discriminative pain sensation from body/head pathway ->
spinothalamic tract/trigeminothalamic → reticular formation → thalamus (VPL/VPM) → cortex postcentral gyrus → localized pain response
The nondiscriminative pain sensation from body pathway ->
spinoreticular tract → reticular formation → thalamus (non discriminative) → hypothal/cortex → emotional non localized pain response
The 5 special senses that input to reticular formation:
vision, auditory, equilibrium, olfaction, taste
T/F Probably all conscious sensory input is modulated by the reticular system
True
The sensory/motor pathway from the cortex through the reticular formation ->
sensory/motor cortex→reticular formation (PPN)→reticulospinal tracts→affect extensor motor neurons→affect posture
The motor pathway from the cerebellum through the reticular formation ->
cortex→reticular→fastigial nuc. & vermal/paravermal
The autonomic chemo and baro receptors pathway through the reticular formation ->
chemo- & baro-receptors→CN 9, 10→inf. Gang. CN9,10→solitary nuc→reticular formation →dorsal motor nuc/ventrolateral→ parasympathetic/sympathetic control blood pressure
T/F the reticular afferent input includes input from the limbic and hypothalamus
True
Efferent output of reticular system to nonspecific thalamic nuc. (reticular, intralaminar nuc.)→
a) cortex directly to modulate (excite or inhibit) sensory function/cortical excitability→state of consciousness
b) specific thalamic nuclei directly → cortex indirectly→state of consciousness
Efferent output of reticular system to periaquiductal gray ->
-> raphe nuc→serotonin→spinal cord→inhibit spinothalamic tract pain transmission
Efferent output of reticular system monamine and cholinergic nucleus:
raphe nuclei→
Serotonin
Efferent output of reticular system monamine and cholinergic nucleus:
locus ceruleus→
NEpi
Efferent output of reticular system monamine and cholinergic nucleus:
pedunculopontine nuc→
ACh
Efferent output of reticular system monamine and cholinergic nucleus:
ventral tegmental nuc.→
dopamine
Efferent output of reticular system to the spinal cord:
Medial and lateral reticulospinal tract -
entire SC stim axial m:
-facilitate posture, modulate muscle tone, and mediate spinal cord somatomotor reflex activity
Efferent output of cerebellar cortex through the reticular system ->
cortex→reticular→fastigial nuc. &v ermal/paravermal→posture/balance
Efferent output of horizontal gaze center through the reticular system:
CN 3 (med. Rectus) & CN 6 (lat. Rectus)→horizontal eye movements in response to changes in body/head position
The autonomic medullary reticular formation of the ventrolateral medulla sympathetic pathway on BP ->
sympathetic→spinal cord lateral horn sympathetic → vasoconstrict/dilate→affect BP
How does the reticular formation affect respiration ->
reticular formation→ spinal cord ventral horn phrenic nerve → diaphragm → respiration
What is the RAS?
Sleep/Wake, Level Conscousness
What will an ECG show us?
rhythmic brain electrical activity
What are alpha rhythms?
Awake
What are beta rhythms?
REM sleep = dreaming
What will the reticular formation do to prevent us from acting out dreams?
inhibits muscle activity
How does the reticular formation regulate our wakefulness/sleep?
reticular formation increases or decreases activity of thalamus and cortex to regulate wakefulness/sleep
When the Pedunculopontine nuc secretes ACh and the raphe nucleus secretes serotonin, what state are we in?
Sleep
When locus ceruleus secretes NEpi, what state are we in?
Awake
