THALAMUS
| A | Vision | |
| B |
Hearing |
|
| C |
Balance |
|
| D |
Smell |
The medial geniculate body is an eminence on the inferior surface of the thalamus lateral to the midbrain. Which of the following function is related to medial geniculate body?
| A |
Vision |
|
| B |
Hearing |
|
| C |
Balance |
|
| D |
Smell |
- Ans.B
- Medial geniculate body receives input independently from the cochlear nuclei (hearing). Projections then continue on to the primary superior temporal convolution (transverse gyri of Heschl).
- Lateral geniculate body is concerned with vision.
Which of the following in not a part of Epithalamus:
| A |
Pineal body |
|
| B |
Posterior commissure |
|
| C |
Trigonum Habenulae |
|
| D |
Geniculate bodies |
D i.e. Geniculate body
Which of the following is/are the ventral posterior neucleus of thalamus:
| A |
Medial lemniscus |
|
| B |
Lateral lemniscus |
|
| C |
Corticospinal |
|
| D |
All |
A. i.e. Medial lemniscus
The nucleus involved in Papez circuit is:
| A |
Pulvinar |
|
| B |
Intralaminar |
|
| C |
VPL nucleus |
|
| D |
Anterior nucleus of Thalamus |
D i.e. Anterior nucleus of Thalamus
Sensations which are appreciated in thalamus
| A |
Proprioception |
|
| B |
Pain & temperature |
|
| C |
Tactile sensations |
|
| D |
Pressure |
Ans. is ‘b’ i.e., Pain & temperature
Pain and temperature are primarily appreciated by the thalamus.
For other forms of sensation, the thalamus is unable to analyze the details of sensations.
Fibers carrying tactile and proprioceptive information ascend through the thalamocortical pathway to area 3 of primary somatic sensory cortex through the thalamic radiation.
Therefore, if the somatosensory cortex is removed, tactile sensations and proprioceptions are lost, but pain and temperature sensations persist.
| A | Anterior nucleus | |
| B |
Intralaminar nucleus |
|
| C |
Dorsal nucleus |
|
| D |
Pulvinar nucleus |
Ans. is ‘a’ i.e., Anterior nucleus
Motor nuclei (ventral anterior and ventral lateral) of thalamus relay and process messages from basal ganglia (especially globus pallidus) and cerebellum to the motor and premotor cortex.
From a functional point of view, thalamic nuclei are divided into:‑
A) Specific sensory nuclei (relay nuclei):- These nuclei receive all sensory afferents from ascending pathways and project to the somatosensory cortex. These include ventroposterior nucleus and medial & lateral geniculate bodies.
B) Association nuclei:- These nuclei have reciprocal connections with the association areas of the cerebral cortex and therefore help in integration of different type of sensory information. These nuclei include the lateral group of nuclei (Pulvinar, lateral dorsal, lateral posterior nuclei) and part of the medial dorsal nucleus.
C) Nonspecific nuclei:- These nuclei also receive sensory information but project to the cortex in a diffuse manner. Therefore they seem to be involved in the arousal induced by sensory stimuli. These nuclei are intralaminar and reticular nuclei.
D) Motor nuclei:- There nuclei relay and process messages from the basal ganglia and cerebellum to motor and premotor cortex. These nuclei are ventral anterior and ventral lateral nuclei.
