diencephalon i
DESCRIPTION
DIENCEPHALON I. Dr. Ahmed Fathalla Ibrahim. DIENCEPHALON. ORIGIN: from prosencephalon COMPONENTS: from dorsal to ventral: epithalamus, thalamus, subthalamus & hypothalamus CAVITY: third ventricle. EPITHALAMUS. SITE: above superior colliculus, dorsal to thalamus COMPONENTS: - PowerPoint PPT PresentationTRANSCRIPT
Dr. Ahmed Fathalla Ibrahim
DIENCEPHALONDIENCEPHALON• ORIGIN:ORIGIN: from prosencephalon
• COMPONENTS: COMPONENTS: from dorsal to ventral: epithalamus, thalamus, subthalamus & hypothalamus
• CAVITY: CAVITY: third ventricle
EPITHALAMUSEPITHALAMUS• SITE: SITE: above superior colliculus,
dorsal to thalamus• COMPONENTS:COMPONENTS:1.1. Pineal gland: Pineal gland: secretes melatonin that
regulates onset of puberty2.2. Habenular nuclei: Habenular nuclei: a part of limbic
system
THALAMUSTHALAMUS
SHAPE: SHAPE: • An oval mass of grey matter• Both thalami are joined by
interthalamic adhesioninterthalamic adhesion
RELATIONS OF THALAMUSRELATIONS OF THALAMUS
THALAMUSTHALAMUSRELATIONS:RELATIONS:• Superior:Superior:1.1. Its lateral part Its lateral part is related to caudate nucleus2.2. Its medial part Its medial part forms the floor of lateral
ventricle• Inferior: Inferior: hypothalamus & subthalamus• Medial: Medial: forms the lateral wall of third
ventricle• Lateral: Lateral: posterior limb of internal capsule
separating it from lentiform nucleus
SUBDIVISIONS OF THALAMUSSUBDIVISIONS OF THALAMUS
CONNECTIONS OF THALAMUSCONNECTIONS OF THALAMUS
ANTERIOR GROUP OF NUCLEI:ANTERIOR GROUP OF NUCLEI:• A part of limbic system limbic system• Concerned with recent memory, recent memory,
emotion, behavioremotion, behaviorAnterior groupAnterior group Cingulate gyrusCingulate gyrus
HippocampusHippocampusMammillary bodyMammillary body
CONNECTIONS OF THALAMUSCONNECTIONS OF THALAMUS
MEDIAL GROUP OF NUCLEI:MEDIAL GROUP OF NUCLEI:• A part of limbic system limbic system• Concerned with control of mood & of mood &
emotionemotion
HypothalamusHypothalamus
Prefrontal cortexPrefrontal cortexMedial groupMedial group Prefrontal cortexPrefrontal cortex
CONNECTIONS OF THALAMUSCONNECTIONS OF THALAMUS
LATERAL GROUP OF NUCLEI:LATERAL GROUP OF NUCLEI:• Specific nucleiSpecific nuclei• Non specific nucleiNon specific nuclei
SPECIFIC NUCLEISPECIFIC NUCLEI
VENTRAL POSTERIOR:VENTRAL POSTERIOR:• VENTRAL POSTERIOR LATERAL (VPL)VENTRAL POSTERIOR LATERAL (VPL)• VENTRAL POSTERIOR MEDIAL (VPM)VENTRAL POSTERIOR MEDIAL (VPM)LATERAL GENICULATE BODY (LGB)LATERAL GENICULATE BODY (LGB)MEDIAL GENICULATE BODY (MGB)MEDIAL GENICULATE BODY (MGB)VENTRAL ANTERIOR (VA)VENTRAL ANTERIOR (VA)VENTRAL LATERAL (VL)VENTRAL LATERAL (VL)
SPECIFIC NUCLEISPECIFIC NUCLEI
Medial leminiscusMedial leminiscus
Spinal leminiscusSpinal leminiscusVPLVPL
Trigeminal leminiscusTrigeminal leminiscus
Taste fibresTaste fibres
VPMVPM
Sensory cortexSensory cortex
SPECIFIC NUCLEISPECIFIC NUCLEI
Optic tractOptic tract LGB LGB Visual cortexVisual cortex
Inferior Inferior MGB MGB Auditory cortex Auditory cortexcolliculuscolliculus
Globus Premotor &Globus Premotor &pallidus Motor cortexpallidus Motor cortex
VAVAVLVL
NON SPECIFIC NUCLEINON SPECIFIC NUCLEI
• LATERAL DORSALLATERAL DORSAL• LATERAL POSTERIORLATERAL POSTERIOR• PULVINARPULVINAR
They are connected to wide areas of They are connected to wide areas of cerebral cortexcerebral cortex
CONNECTIONS OF THALAMUSCONNECTIONS OF THALAMUS
INTRALAMINAR NUCLEUS (IL):INTRALAMINAR NUCLEUS (IL):• Control all level of activities of cerebral
cortex
Reticular formationReticular formation
Specific thalamic nucleiSpecific thalamic nucleiILIL All cortical areasAll cortical areas
CONNECTIONS OF THALAMUSCONNECTIONS OF THALAMUS
RETICULAR NUCLEUS (RN):RETICULAR NUCLEUS (RN):• Control mechanism of cerebral cortex
over thalamus
All cortical areasAll cortical areas RNRN All thalamic nucleiAll thalamic nuclei
THALAMIC LESIONTHALAMIC LESION
THALAMIC SYNDROME:THALAMIC SYNDROME:• Contralateral hemianaesthesiaContralateral hemianaesthesia• Occurrence of spontaneous painOccurrence of spontaneous pain• Contralateral hemiparesisContralateral hemiparesis• ChoreoathetosisChoreoathetosis