BRAIN ANATOMYPART II

TELENCEPHALON

Kaan Yücel M.D.,Ph.D. 6.December.2013 Friday

IN 15 QUESTIONS

Learning Objectives

Explain the components of the telencephalon

Explain the boundaries, gyri, sulci in each lobe

Explain the major Brodmann areas in each lobe

Explain the ventricular system

Explain the features of white matter tracts

1. Telencephalon is composed of… Cerebral hemispheresSulci, fissures, gyri, lobespartially separated by a deep longitudinal fissure, and which fill the area of the skull above the tentorium cerebelli and are subdivided into lobes based on their position.

Basal ganglia

Insula

Ventricular systemTwo lateral ventricles, third ventricle, fourth ventricle

White matter tractsCommissural, association, and projection fibres

2. Sulci & Gyri & Lobes Precentral gyrus

3. Temporal lobe & sulci & gyri

4. Occipital lobe & sulci & gyri

5. Occipital lobe & sulci & gyri

6. Insula Island of Reil

7. Medial and inferior aspects of the hemispheres

7. Medial and inferior aspects of the hemispheres

8. Brodmann areas

1909 Cytoarchitecture47 functional areas

Neocortex 6 layers

Paleocortex 3-5

layersArchicortex 3

layers

8. Brodmann areas

3

1

2

5 76

8

9

10

46

46

10

4

4 44 5

47

11

41,42

39

43

22

38

17

18

19

21

37

somesthetic association area

8. Brodmann areas

8. Brodmann areas

9. Lateral ventricles

10. Third ventricle

11. Fourth ventricle

1. Frontal Lobe. 2. Parietal Lobe. 3. Occipital Lobe. 4. Septum Pellucidum. a. Rostrum of Corpus Callosum.b. Body of Corpus Callosum.c. Splenium of Corpus Callosum.10. Pons. 11.Medulla Oblongata. 12. Cerebellum. 13. Spinal Cord. 14. Fourth ventricle. 15. Sinus Confluence.

Cisternae

Correction: Lenticular nucleus or lentiform nucleus

12. Basal gangliaDistributed set of brain structures in the telencephalon, diencephalon, and mesencephalon.

The forebrain structures include :Caudate nucleus Putamen Nucleus accumbens (or ventral striatum) Globus pallidus

Corpus striatum

12. Basal gangliaCaudate nucleus C-shaped structure closely associated with the lateral wall of the lateral ventricle. largest at its anterior pole (the head), and its size diminishes posteriorly as it follows the course of the lateral ventricle (the body) all the way to the temporal lobe (the tail), where it terminates at the amygdaloid nuclei.

12. Basal gangliaPutamen- Caudate separated by anterior limb of the internal capsuleConnected by bridges of cells across the internal capsuleA striated look striatum or neostriatum

Caudate+ Putamen=Striatum= Main recepient of afferent input.Globus pallidus= Major efferent output leaves from.

12. Basal ganglia

MRI of the brain, T1-weighted axial cut.1, Putamen. 2, Pallidum. 3, Caudate nucleus. 4, Insula. 5, Lateral ventricle. 6, Thalamus.

Third ventricle

Functional Anatomy of the Basal Ganglia

Traditionally, the basal ganglia have been viewed as motor structures.

It is only in the past 20 years that it has been recognized that these structures also may have a role in cognition and emotion.

Functional Anatomy of the Basal Ganglia

Alexander and his colleagues that the motor circuit is involved in

‘‘the control of movement direction and in the scaling of movement amplitude or velocity’’ and ‘‘in the programming and initiation of internally generated movements.’’

Functional Anatomy of the Basal Ganglia

o GABA, dopamine, acetylcholine, and glutamine

o Multiple pathways in the basal ganglia both with both excitatory and inhibitory functions.

o Input to the basal ganglia is received from both the cerebral cortex and the thalamus.

o Lesions in the basal ganglia result in uncoordinated and disorganized movement.

EXTRAPYRAMIDAL SYSTEM

Functional Anatomy of the Basal Ganglia1. motor - between additional motor area of the cerebral cortex and

the lateral part of dorsal striatum – putamen automatic motor activity control of muscular tensioninitiating and fluent performing of motor actions executed by skeletal muscles especially during will dependent movements

2. oculomotor - between the frontal visual eye field of the cerebral cortex and the corpus of the caudate (nucleus caudatus) belonging to the medial part of dorsal striatum

Functional Anatomy of the Basal Ganglia

3. prefrontal (associative) - between dorso-lateral prefrontal cortex and the dorso-lateral part of the head of caudate (nucleus caudatus) (the frontal part of the medial part of dorsal striatum)

choice of aims, planning, programming of the sequence of mental actions and behaviours, switching between sentences (the ability to change attitude flexibly), verbal and spatial working memory, selfcontrol and metacognition (self-consciousness)

Functional Anatomy of the Basal Ganglia

4. latero-orbito-frontal - between lateral orbito-frontal cerebral cortex and the ventromedial part of the head of caudate (medial part of the dorsal striatum

initiating social behaviours motivated by an award and in inhibiting behaviours, which can trigger punishment Dysfxn=> disinhibition

Functional Anatomy of the Basal Ganglia

5. limbic (circuit of the anterior part of the cingular gyrus) - between the anterior part of the anterior cingulate gyrus and the ventral striatum (of which the main part is the nucleus accumbens).

behavior control and adaptation of behaviours after making a mistake.

responsible for correcting behavior following a mistake

12. Basal ganglia

12. Basal gangliaPangelinan MM, Zhang G, VanMeter JW, Clark JE, Hatfield BD, Haufler AJ. Beyond age and gender: relationships between cortical and subcortical brain volume and cognitive-motor abilities in school-age children. Neuroimage. 2011 14;54(4):3093-3100.

Almeida Montes LG, Ricardo-Garcell J, Barajas De La Torre LB, Prado Alcántara H, Martínez García RB, Fernández-Bouzas A, Avila Acosta D. Clinical correlations of grey matter reductions in the caudate nucleus of adults with attention deficit hyperactivity disorder. J Psychiatry Neurosci. 2010;35(4):238-246.

Mitelman SA, Canfield EL, Chu KW, Brickman AM, Shihabuddin L, Hazlett EA, Buchsbaum MS. Poor outcome in chronic schizophrenia is associated with progressive loss of volume of the putamen. Schizophr Res. 2009;113(2-3):241-245.

12. Basal ganglia

MRI of the brain, T1-weighted coronal cut.1, Lateral ventricle. 2, Caudate nucleus. 3, Putamen. 4, Temporal lobe (left side). 5, Sylvian fissure (lateral sulcus).

13. Commissural fibers CORPUS CALLOSUMFreitag CM, Luders E, Hulst HE, Narr KL, Thompson PM, Toga AW, Krick C, Konrad C.Total brain volume and corpus callosum size in medication-naïve adolescents and young adults with autism spectrum disorder. Biol Psychiatry. 2009;66(4):316-319.

Kitayama N, Brummer M, Hertz L, Quinn S, Kim Y, Bremner JD. Morphologic alterations in the corpus callosum in abuse-related posttraumatic stress disorder: a preliminary study. J Nerv Ment Dis. 2007;195(12):1027-1209.Ballmaier M, Kumar A, Elderkin-Thompson V, Narr KL, Luders E, Thompson PM, Hojatkashani C, Pham D, Heinz A, Toga AW. Mapping callosal morphology in early- and late-onset elderly depression: an index of distinct changes in cortical connectivity. Neuropsychopharmacology. 2008;33(7):1528-1536.

Black SE, Moffat SD, Yu DC, Parker J, Stanchev P, Bronskill M. Callosal atrophy correlates with temporal lobe volume and mental status in Alzheimer's disease. Can J Neurol Sci. 2000;27(3):204-209.Venkatasubramanian G, Jayakumar PN, Reddy VV, Reddy US, Gangadhar BN, Keshavan MS Corpus callosum deficits in antipsychotic-naïve schizophrenia: evidence for neurodevelopmental pathogenesis. Psychiatry Res. 2010;182(2):141-145.

1. Genu of corpus callosum

2. Forceps minor 3. Anterior limb of

internal capsule 4. Septum

pellucidum 5. Caudate nucleus 6. Putamen 7. Globus pallidus 8. Posterior limb of

internal capsule 9. Thalamus 10. Splenium of

corpus callosum 11. Forceps major

13. Commissural fibers ANTERIOR COMMISSUREPOSTERIOR COMMISSURE

14. Association fibers

15. Projection fibers

1st neuron2nd neuron3rd neuron

Internal capsuleAnterior limb [3]Posterior limb [8]Genu

Motor homunculusSensory homunculus

Motor homunculusSensory homunculus