Forebrain Flashcards
Rostral boundary of diencephalon
Anterior commissure and lamina terminalis (wall of 3rd ventricle)
Caudal boundary of diencephalon
Posterior commissure (divides diencephalon from midbrain)
Dorsal boundary of diencephalon
Roof of diencephalon
Ventral boundary of diencephalon
Base of hypothalamus
Lateral boundary of diencephalon
Internal capsule (divides it from lenticular nuclei)
Medial limits of diencephalon
3rd ventricle
Portions of thalamic nuclei
Anterior, medial,lateral
Anterior nucleus of the thalamus has connections with :
Hippocampal formation, cingulate gyrus, mammillary bodies
Anterior nucleus of thalamus function
Memory function and regulation of emotional behavior
What nucleus lies posterior to anterior nucleus
Dorsomedial nucleus
What separates dorsomedial nucleus from lateral thalamus
Internal medullary lamina
Dorsomedial nucleus function
Mediates affective processes and emotional behavior
Nuclei inside of lateral thalamus
VA, VL, LD, VPL, VPM, LP
Ventral anterior nucleus (VA) and Ventral lateral nucleus function
Control of motor functions
Ventral basal complex
VPL VPM
Function of VPL, VPM
Relay somatosensory info from body and head to POSTCENTRAL GYRUS
Lateral posterior nucleus (LP) function
sensory input and cognitive functions associated with them
Nuclei in posterior thalamus
Pulvinar nucleus, medial geniculate nucleus, lateral geniculate nucleus
Pulvinar nucleus functions
Cognitive function involving auditory and visual stimuli
Medial geniculate nucleus function
Important relay for auditory system
Lateral geniculate nucleus function
Relay of visual impulses to visual cortex from BOTH retinas
Non specific thalamic nuclei function
Modulate activity of the major nuclei of the thalamus
Non specific thalamic nuclei
Midline thalamic nuclei, reticular nucleus, intralaminal nuclei (centromedian nucleus)
Forms the roof of the diencephalon
Epithalamus
Epithalamus structures
Habenular complex, Stria medullaris, pineal gland
Habenular complex nuclei
Medial and lateral nucleus
Commissure that connects medial and lateral habenular nucleus
Habenular commissure
Pathway arising from medial habenular nucleus
Habenular peduncular tract
Habenular peduncular tract (fasciculus retroflexus)
Projects to ventral part of midline tegmentum (intrapeduncular nucleus) FUNCTION UNKNOWN
Pathway arising from lateral habenular nucleus
Stria medullaris
Stria medullaris contains
Habenular AFFERENT fibers
What passes through Stria medullaris
Afferent and Efferent fibers linking habenular nuclei with lateral hypothalamus, preoptic region, sustancia innominata ( region lateral to preoptic region), septal area, anterior thalamic nucleus
Habenular complex function
- Relay where limbic system and hypothalamus can influence activity of midbrain structures (reticular formation, brain stem neurotransmitter functions )
- pain processing
- stress
- learning
- reward processing
- depression * (deep stimulation of afferent fibers of Stria med. used to treat disorder )
Pineal gland location
Attached to roof of posterior 3rd ventricle
Where does Pineal gland receive info from
Sympathetic nervous system via superior cervical ganglia
Pineal gland circadian rhythm to light
Releases hormones, due to indirect pathway that relays info DIRECTLY from retina to Suprachiasmatic nucleus then INDIRECTLY to intermediolateral cell column of the thoracic cord. Then light cycle info is relayed to Superior cervical ganglia that has direct connection with pineal gland
Cells found in pineal gland
Secretory cells called pinealocytes that secrete: melatonin, serotonin, norepinephrine, hypothalamic releasing hormone (ThyrotropinRH, somatostatin, LHRH)
Subthalamus location
Posterior 3rd of diencephalon
Subthalamic function
Motor functions related to basal ganglia
Subthalamus nuclei
Subthalamic nucleus, zona incerta
Subthalamic nucleus function
Connects with globus pallidus and regulates motor function by basal ganglia
Zona incerta role
Function unknown, separates lenticular fasciculus from thalamic fasciculus
Hypothalamus regulates
Sympathetic, parasympathetic events, endocrine functions of pituitary gland, sexual behavior, feeding and drinking behavior, affective processes (fight or flight)
Lateral hypothalamus contains
Medial forebrain bundle and associated with behavior and predation
Medial hypothalamus contains
Most of releasing hormones that control pituitary gland, feeding, affective processes, autonomic functions
Important nuclei of Anterior hypothalamus and preoptic region
Preoptic nuclei, suprachasmatic, supraoptic, paraventricular nuclei
Medial Preoptic region function
Regulation of endocrine function and temp regulation
Lateral preoptic region functions
Unknown
Suprachiasmatic nucleus function
Receives retinal input, associated with diurnal rhythms for hormone release
Paraventricular nucleus and supraoptic function
Synthesize vasopressin and oxytocin
Mid level of hypothalamus contains
Arcuate nucleus , ventromedial nucleus, tuberal nuclei
Arcuate nucleus function
Dopaminergic neurons , source of prolactin release-inhibiting hormone and feeding behavior
Ventromedial nucleus function
Endocrine control, rage behavior
Lesions of ventromedial nucleus
Obesity
Tuberal nuclei function
Release regulatory hormones (releasing or release-inhibiting hormones) transmitted through portal system to ant pituitary gland and control release of hormones from this region
Posterior hypothalamus structures
Mammilothalamic tract
Componentes of basal ganglia
Caudate nucleus, putamen, and globus pallidus, substancia nigra, subthalamic nucleus
Neostriatum
Caudate nucleus and putamen
Major site of input into the basal ganglia from cerebral cortex, thalamus and sustancia nigra
Neostriatum
Globus pallidus function
Primary region for outflow of info from the basal ganglia to cerebral cortex via thalamic nuclei
Ansa lenticularis (Fiber pathway of Basal ganglia)
Emerges from medial segment of globus pallidus and passes ventromedially and caudal to midbrain
Lenticular fasciculus
Passes in a dorsomedial direction from pallidum around dorsal surface of subthalamic nucleus
Dentatothalamic fibers
Where both ansa lenticularis and lenticular fasciculus appear to merge rostral to red nucleus + fibers of cerebellum
Collectively called THALAMIC FASCICULUS
H1 field of forel
Thalamic fasciculus
H2 field of Forel
Lenticular fasciculus
Limbic system structures
Hippocamapl formation, septal area, amygdala, and adjoining regions of cortex
Limbic system function
Associated with olfactory function
Additional structures associated with limbic system
Frontal cortex and cingulate gyrus
Major outflow pathway of hippocampal formation
Fornix
Component of Fornix that is distributed to diencephalon
Postcommissural fornix
Component of fornix that is distributed to septal area
Precomissural fornix
Hippocampal formation + septal area regulate
Emotional behavior, motivational processes, hormonal and autonomic regulation, and memory functions
Septal area alone modulates
Aggression, rage, endocrine and reproductive functions
Bed nucleus of Stria terminalis
Believed to regulate autonomic, endocrine, and effective processes normally associated with amygdala
Nucleus accumbens
Head of caudate nucleus; receives large dopaminergic projection from brainstem, amygdala, and parts of hippocampal formation and projects them to sustancia innominata, sustancia nigra, and ventral tegmental area.
Sequences of motor processes associated with affective processes
Sustancia innominata
Relay of signals from parts of amygdala to lateral hypothalamus
Pathway of Amygdala
Stria terminalis
Internal capsule fibers
Descending fibers from cerebral cortex to brain stem and spinal cord plus ascending fibers from thalamus to cerebral cortex
Internal capsule function
Sensorimotor functions
Anterior commissure fibers
Olfactory fibers from anterior olfactory nucleus to contralateral olfactory bulb
Thalamus injury
Thalamic pain syndrome- very painful and unpleasant sensation that persists
Damage to hypothalamic nuclei
Disorders of eating, endocrine function, temp regulation, aggression and rage, sympathetic disfunction,
Diabetes insipidus is an example ( damage to vasssopresin neurons in supraoptic or paraventricular nuclei)
Diseases of basal ganglia
Movement disorders (abnormal, involuntary movement at rest “Dyskinesia”) Example Parkinson’s disease ( loss of dopamine release from sustancia nigra) Chorea (hyperkinetic disorder loss of y-aminobutyric acid in stratium, heminallism (damage to subthalamic nucleus)
Disruptions in limbic system
Changes in emotional behavior, irritability, impulsivity, rage.
Hippocampal formation- loss of short term memory
Prefrontal cortex- decreased cognitive ability
Temporal lobe- seizures
Dysfunctions of Cerebral cortex
1- upper motor neuron paralysis (precentral and premotor cortices)
2- types of aphasias
3- apraxias
4- loss of somatosensory and auditory discrimination post central and superior temporal gyrus