2 DiencephalonThis represents the central core of the forebrain and is surrounded by the cerebral hemispheres. It is made up of three major paired structures: The thalamusThe hypothalamusThe epithalamus
3 DiencephalonThalamus is a bilateral egg shaped nuclei that makes up 80% of the diencephalon. It is the relay station for information coming into the cerebral cortex.
4 ThalamusThe thalamus is a collection of smaller nuclei, each having a functional specialty. All afferent impulses converge on to the thalamus and synapse with at least one of its nuclei. It serves as the gateway to the cerebral cortex.
5 ThalamusAll the sensory fibers except olfaction go through one of the thalamic nuclei. For example the lateral geniculate nuclei receive input from the retina. The thalamus also plays an important role in sleep.
6 Dorsal nucleiMedialLateraldorsalLateralposteriorPulvinarAnteriornucleargroupMedialgeniculatebodyReticularnucleusLateralgeniculatebodyVentralpostero-lateralVentralanteriorVentrallateralVentral nuclei(a) The main thalamic nuclei. (The reticular nuclei that “cap” the thalamus laterally are depicted as curving translucent structures.)
7 ThalamusDisorders of the Thalamus are usually due to stroke which can lead to the thalamic pain syndrome.
8 HypothalamusHypothalamus lies just below the thalamus and forms the lower walls of the third ventricle. It is the major visceral control center of the body and is the major center for regulating the body’s homeostatic mechanisms.
9 These functions include: HypothalamusThese functions include:Autonomic controlEmotional responseTemperature regulationFood intakeWater balanceSleep wake cyclesEndocrine function
10 Epithalamus forms the roof of the third ventricle Epithalamus forms the roof of the third ventricle. Its most visible landmark is the pineal gland which secretes melatonin and is involved in the sleep wake cycle.
12 Brains StemThe brain stem is made up of the midbrain, pons and medulla oblongata. The brain stem produces programmed automatic behaviors necessary for survival. It is similar in make up to the spinal cord and consists of projection fibers.
13 PonsIt is noticeable as a bulge on the anterior surface of the brain stem. It is made up of conduction tracts. Dorsally it forms part of the forth ventricle.
14 Medulla OblongataIt is the most inferior part of the brain stem. As it passes through the foramen magnum, it becomes the spinal column.
16 Medulla OblongataThe medulla plays an important role in maintaining certain autonomic functions including: Heart rateRespirationSwallowing, sneezing & vomiting
17 HangingThe medulla oblongata is destroyed when a person is hung, leading to “instant” death.
18 CerebellumIt consists of two hemispheres connected by the vermis. It is highly convoluted and has gyri known as folia. The cerebellum controls body movements. It is also involved in recognizing the sequence of events so adjustments in limb action can be made. Disorders are described as an ataxia.
20 Functional Brain Systems Functional brain systems are networks of neurons that incorporate various areas of the brain. Two major systems are the:Limbic systemReticular formation
21 Limbic SystemLimbic System is a groups of structures located on the medial aspect of each cerebral hemisphere and the diencephalon. Its cerebral structures encircle the brain stem.
22 Limbic SystemIt is a complex system with multiple functions. Included in it are the:Septal nucleiCingulate gyrusParahippocampal gyrusDentate gyrusHippocampusAmygdalaThese are all found in the cerebrum
23 Limbic SystemIn the diencephalon:HypothalamusThalamic nuclei
24 The limbic system is our emotional brain. The Amygdala recognizes angry or fearful facial expressions and assesses danger.The cingulate gyrus plays a role in expressing our emotions through gestures and helping us to “cope”.The hippocampus is involved with long term memory
25 The limbic system is our emotional brain. Dentate gyrus is thought to regulate happiness Parahippocampal gyrus is thought to regulate spatial memory
26 Primary somatosensory cortex CingulategyrusPrimarymotor cortexPremotor cortexCentral sulcusCorpuscallosumPrimary somatosensorycortexFrontal eye fieldParietal lobeSomatosensoryassociation cortexPrefrontalcortexParieto-occipitalsulcusOccipitallobeProcesses emotionsrelated to personaland social interactionsVisualassociationareaOrbitofrontalcortexOlfactory bulbOlfactory tractPrimaryvisual cortexFornixTemporal lobeUncusCalcarine sulcusPrimaryolfactory cortexParahippocampalgyrus(b) Parasagittal view, right hemispherePrimary motor cortexMotor association cortexPrimary sensory cortexSensory association cortexMultimodal association cortex
30 Reticular FormationThis system extends from the medulla oblongata, pons and midbrain. The reticular formation is involved in actions such as awaking/sleeping cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli.
31 Reticular FormationLesions affecting the reticular formation cause severe alterations in level of consciousness and coma.