Thalamus and Limbic system

مالحظة: .هذا الملف للمراجعة وترتيب المعلومات فقط وليس مرجع للمذاكرة النه ليست كل المعلومات متضمنة

Done by: رند الحميضي “found in “:

is the largest nuclear mass of the body , it is our pathway to the cortex “ last relay site “ , except “ olfaction “ they go directly to the cortex without passing by it.

lateral nuclear group , medial , anterior “names only”: Lateral:(L) :Posterior limb of the internal •its projection called the capsule Anterior anterior tubercle. •It lies just behind the end interventricular foramen. Medial: Superior: (s) "3rd ventricle" Lateral has 4 connected to ventricle and surfaces fornix. thalamus of the opposite side by the Massa intermedia. • projection called Pulvinar Posterior • lies above the superior Inferior: (I) colliculus and the lateral & , end: medial Geniculate bodies anteriorly & posteriorly.

Internal medullary lamina: External medullary lamina: Bundle of myelinated (afferent & efferent) fibers. Covers the lateral surface. divide the thalamus into: anterior , It consists of thalamocortical & medial, lateral nuclear groups each corticothalamic fibers one of them contain bunch of nuclei

Projection of thalamic nuclei :

Name of Nucleus Afferent Efferent

Anterior Thalamic Nucleus .” under the Cingulate gyrus, (limbic system) hypothalamus Medial Nucleus or dorso medial Hypothalamus. Frontal &Prefrontal cortex Ventral Anterior Nucleus body. . Ventral Lateral Nucleus Dentate Nucleus “cerebellum “ . Ventral Posterior Lateral Nucleus Medial and spinal leminsci. Sensory cortex. Ventral Posterior Medial Nucleus Trigeminal Leminiscus Sensory cortex. Lateral geniculate body optic tract. visual cortex Medial geniculate body auditory cortex.

LIMBIC SYSTEM Latin word means edge or border, separates the medial surface of the cerebral cortex from the diencephalon, consists of a number of cortical & subcortical structures with looped connections that all project to the hypothalamus (particularly mammilary bodies).  4 main Function: Emotions, Memory, Visceral & Motor responses, Olfaction.  4 main structure : Limbic cortex, Hippocampus”memory” Amygdala, Septal area.

Cortical structure Hippocampus Amygdala Septal area 1. Limbic lobe. 1-Site: horseshoe paired 1-site: temporal 1-site :anterior to the C-shaped ring of structure found in temporal pole. interventricular surrounding the corpus callosum. lobe. septum It includes: 2-function: FEAR , Subcallosal area ,Cingulate gyrus 2-function: Emotions Anger, Isthmus,Parahippocampal gyrus and *forming new memories and &Hormonal 2-Function: theUncus. connecting emotions to it. secretions. pleasure zone *acts as a memory indexer by sending memories to cerebral 3-main connection: 3-Main connections: hemisphere for long-term *Inputs: 1-To Hypothalamus storage and retrieving . Association areas of 2-To The hippocampus necessary for visual, auditory & consolidation of new short- somatosensory term memories. cortices.

3-main connection: * Outputs: efferent pathway “FORNIX”: Hypothalamus & C-shaped group of fibers Autonomic nuclei in connecting the hippocampus the brain stem, with mammillary body. 2. Hippocampal consists of: 4-Lesion: formation.”hippocampus Fimbria, Crus,Body ,Column. Lack of emotional with dendate gyrus” The Fornix is an important responses &docility.

3. Septal areas. component of PAPEZ CIRCUIT 4. Prefrontal area.

Lesions associated with limbic lobe disorders: Korsakoff’s psychosis Temporal lobe epilepsy Alzheimer’s disease: Schizophrenia

Deficiency of thiamine The hippocampus is a The hippocampus is failure to recognize (vitamin B-1) & alcoholic common focus site in one of the first brain what is real. intoxication. epilepsy can be damaged areas to show damage

Will lead to: through chronic seizures. in Alzheimer's. 1-Retrograde :loss of new memories at the time of lesion with retained old *sometimes damaged in memories diseases such as” herpes 2- Anterograde amnesia: encephalitis” inability to gain new memories.

*very helpful video “ limbic system “ by khan academy :

https://www.youtube.com/watch?v=GDlDirzOSI8

Best of luck.