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THALAMUSTHALAMUS

Epithalamus: Habenular NucleiEpithalamus: Habenular Nuclei

Thought to be involved in emotional andvisceral responses to odors.Thought to be involved in emotional andvisceral responses to odors.

Projects to septal nuclei (in thalamus)Projects to septal nuclei (in thalamus)

Via stria medullaris thalami.Via stria medullaris thalami.

Projects to interpeduncular nucleusProjects to interpeduncular nucleus

Via habenulointerpeduncular tract.Via habenulointerpeduncular tract.

Epithalamus: Pineal BodyEpithalamus: Pineal Body

Secretes melatonin (hormone):Secretes melatonin (hormone):

Regulates circadian rhythms.Regulates circadian rhythms.

Activity is modulated by light-dark cycle:Activity is modulated by light-dark cycle:

Via sympathetic inputs activated byhypothalamic suprachiasmatic nucleus.Via sympathetic inputs activated byhypothalamic suprachiasmatic nucleus.

Calcification accrues with maturity.Calcification accrues with maturity.

Lesions associated with precociouspuberty.Lesions associated with precociouspuberty.

ThalamusThalamus

80 percent of diencephalon80 percent of diencephalon

Separated from hypothalamus via:Separated from hypothalamus via:

Hypothalamic sulcus (groove)Hypothalamic sulcus (groove)

Other landmarks:Other landmarks:

Optic recessOptic recess

Infundibular recessInfundibular recess

Pineal recessPineal recess

Thalamus: CommissuresThalamus: Commissures

Habenular :Habenular :

Above the pineal recessAbove the pineal recess

Posterior:Posterior:

Below the pineal recessBelow the pineal recess

Thalamus: FunctionsThalamus: Functions

Relays all sensory information exceptsmell to the cerebral cortex.Relays all sensory information exceptsmell to the cerebral cortex.

Provides crude awareness.Provides crude awareness.

Initial autonomic response of the body tointense pain (physiologic shock).Initial autonomic response of the body tointense pain (physiologic shock).

Interpretation center for crude pain,temperature, light touch, pressure.Interpretation center for crude pain,temperature, light touch, pressure.

Thalamus: FunctionsThalamus: Functions

Plays a role in arousal and alerting.Plays a role in arousal and alerting.

Plays a role in complex reflex movements.Plays a role in complex reflex movements.

Thalamic Sensory Relay NucleiThalamic Sensory Relay Nuclei

Medial geniculate body:Medial geniculate body:

AuditoryAuditory

Projects to primary auditory cortex in temporal lobeProjects to primary auditory cortex in temporal lobe

Lateral geniculate body:Lateral geniculate body:

VisualVisual

Projects to primary visual cortex in occipital cortexProjects to primary visual cortex in occipital cortex

Ventral posterior nuclei:Ventral posterior nuclei:

General sensations and tasteGeneral sensations and taste

Thalamic Motor Relay NucleiThalamic Motor Relay Nuclei

Ventral lateral:Ventral lateral:

Voluntary motorVoluntary motor

Ventral anterior:Ventral anterior:

Voluntary motor and arousalVoluntary motor and arousal

SubthalamicSubthalamic

Thalamus Reticular NucleusThalamus Reticular Nucleus

Modifies neuronal activity in the thalamus.Modifies neuronal activity in the thalamus.

May be involved in regulating sleep-wakefulness cycle and levels ofawareness.May be involved in regulating sleep-wakefulness cycle and levels ofawareness.

Thalamus Anterior NucleusThalamus Anterior Nucleus

Concerned with certain emotions andmemory.Concerned with certain emotions andmemory.

Receives input from hippocampus andmamillary bodies (mamillothalamic tract).Receives input from hippocampus andmamillary bodies (mamillothalamic tract).

Thalamus White MatterThalamus White Matter

Internal capsuleInternal capsule

Stratum zonaleStratum zonale

External medullary laminaExternal medullary lamina

Internal medullary laminaInternal medullary lamina