pt707 thalamus

thalamus

located in diencephalon and is part of the forebrain

• sensory relay info center

• helps motor cortex in coordination of voluntary movement

• one part located on each side of third ventricle and anterior part of thalamus forms the posterior boundary for the interventricular

anterior nucleus

function: memory

dorsomedial nucleus (DM)

function: emotions and non-motor frontal lobe functions

ventral anterior nucleus (VA)

function: MOTOR

ventral lateral nucleus (VL)

function: MOTOR

ventral posteromedial (VPM)

present within the internal medullary lamina

• function: somatic sensation of head

ventral posterolateral (VPL) nucleus

present within the internal medullary lamina

• function: somatic, sensation of body

medial geniculate body

function: audition

lateral geniculate body

function: vision

pulvinar

function: visual perception and language

midline (reticular nuclei)

function: attention and arousal

centromedian and intralaminar

function: attention and arousal

role of thalamus

• emotional control (mammillothlamic tract)

• integration of sensations with emotions (smelling something and emotional response of love, disgust, etc.)

• hearing and visual pathway processes (impaired MGB or LGB will affect hearing and vision)

• consciousness (interlaminar nuclei)

• motor control (VA and VL) - voluntary movement control circuit 

  • receive info from GP and send to primary motor cortex

VPM and VPL nuclei lesion

damage causes complete sensory loss

• epicritic and protopatr

lesions of thalamus

may result in:

• complete sensory loss if VPM and VPL nuclei damage

• involuntary, abnormal movements (choreathetosis and ataxia)

• thalamic hand: wrist is pronated and flexed, MCPs flexed, extension of interphalangeal joings

• thalamic pain: excessive pain after thalamic infarct (STROKE) that is contralateral and spontaneous (comes and goes)