forebrain, diencephalon. meninges of the brain. cerebro-spinal fluid
DESCRIPTION
The diencephalon The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to posterior forebrain structures including the thalamus, hypothalamus, posterior portion of the pituitary gland, and pineal gland. The hypothalamus performs numerous vital functions, most of which relate directly or indirectly to the regulation of visceral activities by way of other brain regions and the autonomic nervous system.TRANSCRIPT
Forebrain, diencephalon. Meninges of the brain. Cerebro-spinal
fluid. The diencephalon The diencephalon is the region of the
embryonic vertebrate neural tube that gives rise to posterior
forebrain structures including the thalamus, hypothalamus,
posterior portion of the pituitary gland, and pineal gland. The
hypothalamus performs numerous vital functions, most of which
relate directly or indirectly to the regulation of visceral
activities by way of other brain regions and the autonomic nervous
system. THE DIENCEPHALON EPITHALAMUS THALAMUS SUBTHALAMUS
HYPOTHALAMUS Diencephalon Thalamus dorsal thalamus Hypothalamus
pituitary gland
Epithalamus habenular nucleus and commissure pineal gland
Subthalamus ventral thalamus subthalamic nucleus (STN) field of
Forel Diencephalon Hypothalamus Command for the Thalamus
control of autonomic functions such as heart rate, blood pressure,
hunger, thirst. Role in emotions and motivation (e.g., thoughts
about fear get translated into arousal through hypothalamus.)
Thalamus Chief relay centre for directing sensory messages Helps
regulate awareness Relays commands going to the skeletal muscles
from the motor cortex. Hypothalamus also controls sexual
desire.Together with the pituitary systems (a structure located
close to the hypothalamus, the hypothalamus helps regulate the
endocrine system (I.e., hormones such as adrenaline and
noradrenaline). Classification of Thalamic Nuclei
I. Lateral Nuclear Group II.Medial Nuclear Group III.Anterior
Nuclear Group IV.Posterior Nuclear Group V.Metathalamic Nuclear
Group VI.Intralaminar Nuclear Group VII.Thalamic Reticular Nucleus
Summary of Thalamic Connectivity
I.Sensory Input general sensation special sensation taste,
equilibrium, hearing, vision II.Motor Input cerebellum, basal
ganglia III. Reticular Formation IV.Limbic System mammillary
nucleus hippocampal formation Thalamus Functions of the thalamus I.
Relay functions fromthe spinal cord, brainstem, cerebellum basal
ggl. to the cortex II. Modulatory functions Influences the
excitability of the cx, synchronised vs. desynchronised states
(repetitive and burst firing) III. Integrative functions 1. Sensory
connections (sensory relay station) 2. Motor coordination 3.
Psychological functions (instinct, affection, limbic functions etc)
4. Autonom function control 5. Cortical activation Clinical
Syndromes of the Thalamus
Posterolateral thalamic syndromes sensory disorders Thalamic
(Dejerine-Roussy) syndrome ----- VP nucleus - pain Medial thalamic
syndromes disorders of consciousness thalamic neglect, thalamic
amnesia, akinetic mutism Anterolateral thalamic syndromes motor
disorders paresis, ataxia, motor incoordination, dysphagia Visual
(Optic) Pathway
Modality:Vision Receptor: Photoreceptor Cell of Retina Cranial
Nerve: II (Optic nerve) 1stNeuron: Bipolar Cell 2nd Neuron:
Ganglion Cell optic nerve optic chiasm optic tract 3rdNeuron:
Lateral Geniculate Nucleus optic radiation Termination: Visual
Areas (V I, V II) Brodmann area 17 (V I), 18, 19 (V II) Visual
Pathway 1. Optic nerve 2. Optic chiasm 3. Optic tract
4. Lateral geniculate body 5. Optic radiation 6. Visual cortex
Visual (Optic) Pathway Clinical Features of Visual Pathway
Lesion
1. optic nerve 2. optic chiasm 3. optic tract 4. 5. optic radiation
A. unilateral blindness B. bitemporal hemianopsia C. left
homonymous hemianopsia D. left inferior homony- mous quadranopsia
E. left superior homony- Signs of Visual Pathway Lesion
Optic nerve - ipsilateral blindness Optic chiasm - bitemporal
hemianopsia Optic tract - contralateral homonymous hemianopsia
Optic radiation - contralateral homonymous quadranopsia - intact
light reflex Visual Cortex - macular sparing left inferior optic
radiation lesion right superior quadranopsia
Visual Field Defect left inferior optic radiation lesion right
superior quadranopsia Hypothalamus Limbic System Diencephalon 3rd
ventricle Surrounded by cerebrum Thalamus
Intermediate mass Pineal body Hypothalamus Epithalamus Mammillary
body Pituitary gland epithalamus Located at dorsal part of the
diencephalons, it includes the pinieal body. It secretes melatonin
which signals the nighttime stage of the sleep-wake cycle. pineal
body internal secretion gland habenular triangle habenular nucleus
habenular commissure thalamic medullary stria posterior commissure
subthalamus subthalamic nucleus participate in the function of
extracorticospinal tract