Nb2 - Diencephalon: Thalamus

Front 1

What type of matter is diencephalon, where is it located, and what are its 4 parts?

Back 1

Diencephalon is grey matter located in the walls and on the floor of third
ventricle, and situated rostral to the midbrain and surrounded by the cerebral hemispheres. There are
four major parts.
1) Thalamus
2) Hypothalamus
3) Epithalamus
4) Subthalamus

Front 2

Thalamus - located where, relation to hypothalamic sulcus, function (relation to what 3 pathways)

Back 2

located on the walls of 3rd ventricle

dorsal to the hypothalamic sulcus

The thalamus is the
synaptic relay for most subcortical inputs proceeding to cerebral cortex, including inputs from ascending sensory pathways, motor pathways from basal ganglia and cerebellum, and limbic system pathways.

Front 3

Hypothalamus - located where, relation to hypothalamic sulcus, function, also part of what system

Back 3

located on the floor of the 3rd ventricle

Ventral to the
hypothalamic sulcus

Functions in controlling the autonomic nervous system and endocrine glands; also a major part of the limbic system.

Front 4

Epithalamus - located where, includes what gland (function) and what nucleus (part of what system)

Back 4

located on the roof of the 3rd ventricle

includes the pineal gland, which produces
melatonin, and the habenular nucleus, which is part of the limbic system.

Front 5

Subthalamus - located where, includes what nucleus and what's the nuclei's function

Back 5

Subthalamus is located at the transition zone between the diencephalon and midbrain;

includes the subthalamic nucleus which is involved in somatic motor activity.

Front 6

Major parts of the thalamus - what are the 2 types of fiber bundles found here

Back 6

1) Internal Medullary Lamina
2) External Medullary Lamina

Front 7

Fiber Bundle - Internal Medullary Lamina - consists of what 2 types of fibers running between what, divides the thalamus into what groups

Back 7

Internal medullary lamina consists of input and output fibers running between the
thalamic nuclei;

divides the thalamus into three major nuclear groups: anterior, medial, and
lateral.

Front 8

Fiber Bundle - External Medullary Lamina - consists of what 2 types of fibers to what 2 areas of brain, what type of nuclei are found here, and what is the nuclei's function

Back 8

consists of inputs and outputs to the thalamus and cerebral cortex.

Reticular nucleus is located within these fibers, and regulates thalamocortical transmission by forming connections with the thalamic nuclei which project to cerebral cortex.

Front 9

Major thalamic nuclei - Midline and Intralaminar nuclei - located where, inputs from where, projects where, involved in regulation of what (2)

Back 9

located in the internal medullary lamina

inputs are
from diverse sources, including basal ganglia, spinothalamic fibers, brainstem reticular
formation

project to diffuse areas of cerebral cortex, mainly in frontal and parietal lobes

involved in regulation of alertness and consciousness.

Front 10

Major thalamic nuclei - Anterior nuclei and LD - belong to what 2 systems, major input from what, major output to what

Back 10

belong to the limbic system

major inputs from the mammillary
body by the mammillothalamic tract

major output to the cingulate gyrus

part of the Papez
circuit

Front 11

Major thalamic nuclei - Medial nuclei - important nucleus found here, what it forms, concerned with what trait, major input from what

Back 11

most important nucleus is the mediodorsal nucleus (MD)

MD forms
reciprocal connections to prefrontal cortex

Concerned with mood

major input from the
amygdala

Front 12

Major thalamic nuclei - Ventral anterior (VA) and ventral lateral (VL) nuclei - receive inputs from what 2 areas of brain, project to where

Back 12

receive inputs from the basal
ganglia and cerebellum

project to motor areas in frontal lobe (areas 6, 8 and 4).

Front 13

Major thalamic nuclei - Ventral posterior (VP) - main region of what in thalamus, subdivided into what to parts and what are the functions of these 2 parts

Back 13

the main somatosensory region of thalamus (pain, temperature,
and touch fibers mediated by medial lemniscus, spinothalamic and trigeminothalamic
tracts)

VP is subdivided into a lateral part (VPL) conveying impulses for the body

and a medial part (VPM) conveying impulses for the face to somatosensory cortex (areas 3, 1, 2)
in the postcentral gyrus.

Front 14

Major thalamic nuclei - Lateral posterior (LP) and Pulvinar - have major connections with areas of what part of cortex, what is so special about these areas in this region of the cortex

Back 14

Have reciprocal connections with extensive areas of
Association Cortex in parietal, occipital, and temporal lobes.

Association areas of cerebral
cortex are those regions which receive their major input from other cortical areas rather
than the thalamus.

Front 15

Major thalamic nuclei - Lateral geniculate nucleus (LGN) - receives input from where, what tract involved, projections go where

Back 15

receives fibers from both eyes;

the optic radiations
(geniculocalcarine tract) projects to the primary visual cortex of the occipital lobe.

Front 16

Major thalamic nuclei - Medial geniculate nucleus (MGN) - receives fibers from where, project where in what gyrus

Back 16

receives fibers composing the ascending auditory
pathway, from the inferior colliculus and projects via the auditory radiations to primary auditory cortex (area 41) in the superior temporal gyrus (Heschl's gyri).

Front 17

Two fiber classes provide inputs to the thalamic nuclei.

Back 17

Specific inputs

Regulatory Inputs

Front 18

What are Specific Inputs

Back 18

Specific inputs are axons running in specific subcortical pathways. This information is
relayed to the cerebral cortex

Front 19

What are Regulatory Inputs and where do they come from

Back 19

Regulatory inputs are those contributing to the decision as to whether information leaving the thalamic nuclei will be relayed to cerebral cortex.

These inputs come mainly from the cerebral cortical areas to which the thalamic nucleus projects. Other regulatory inputs come from the thalamic reticular nucleus, brainstem reticular formation, and thalamic intralaminar
nuclei.

Front 20

Specific Inputs include - Medial lemniscus: what type of pathway, projects to what, function

Back 20

Sensory Pathway

Medial lemniscus projects to VPL (two-point tactile, vibration for the body).

Front 21

Specific Inputs - Lateral and anterior spinothalamic tracts: what type of pathway, projects to what, function

Back 21

Sensory Pathway

Lateral and anterior spinothalamic tracts project to VPL (pain temperature, and light
touch for the body).

Front 22

Specific Inputs include - Crossed and uncrossed trigeminothalamic tracts: what type of pathway, projects to what, function

Back 22

Sensory Pathway

Crossed and uncrossed trigeminothalamic tracts project to VPM (two-point tactile,
vibration; pain, temperature, and light touch for the face).

Front 23

Specific Inputs - Optic radiations: what type of pathway, projects to what, function

Back 23

Sensory Pathway

Optic radiations project to LGN (vision).

Front 24

Specific Inputs - Auditory radiations: what type of pathway, projects to what, function

Back 24

Sensory Pathway

Auditory radiations project to MGN (hearing).

Front 25

Specific Inputs - Basal ganglia: what type of pathway, projects to what

Back 25

Motor pathway

Basal ganglia projects mainly to VA

Front 26

Specific Inputs - Cerebellum: what type of pathway, projects to what

Back 26

Motor pathway

Cerebellum projects mainly to VL.

Front 27

Specific Inputs - Mammillary bodies: what type of pathway, projects to what

Back 27

Limbic system pathway

Mammillary bodies project to the Anterior/LP nuclei.

Front 28

Specific Inputs - Prefrontal Cortex: what type of pathway, connections to what

Back 28

Limbic system pathway

Prefrontal cortex has reciprocal connections with MD.

Front 29

Thalamic relay nuclei - Sensory relay nuclei - part of what thalamic nuclei (4), process what inputs (5)

Back 29

(VPL, VPM, lateral and medial geniculate nuclei) processing pain, temperature, two point tactile, visual and auditory inputs.

Front 30

Thalamic relay nuclei - Motor relay nuclei - part of what thalamic nuclei (2) and process inputs from what 2 places

Back 30

(VA and VL) processing inputs from the basal ganglia and
cerebellum.

Front 31

Thalamic relay nuclei - Limbic system nuclei - part of what 2 thalamic nuclei and process inputs from what 2 places

Back 31

(MD and Anterior/LD nuclei) processing inputs from prefrontal
cortex and the mammillary bodies.

Front 32

Thalamic relay nuclei - Association nuclei - project where

Back 32

These thalamic nuclei project to association areas of cerebral cortex

Front 33

All of the above are Thalamic relay nuclei. What are Thalamic relay nuclei and where do they project?

Back 33

These nuclei receive specific fibers and project to distinct regions of cerebral cortex.

Front 34

Lesions to the thalamus - most lesions are due to what

Back 34

Most lesions are due to vascular accidents

Front 35

Blood supply to the thalamus - 3 major arteries and what do they supply?

Back 35

1. Posterior choroidal artery supplies dorsomedial part.

2. Posterior cerebral and posterior communicating arteries supply the remainder.

Front 36

Damage to the posterior thalamus (VPL/VPM) causes a syndrome called the...
And what are the 3 symptoms associated with this syndrome?

Back 36

Thalamic Syndrome

1. Thalamic Pain: pain is distorted; perceived abnormally in intensity and/or modality.

2. Loss of somatic sensation to the contralateral head and body is called Hemianesthesia.

3. Ataxia is loss of balance and a tendency to fall. This is a sensory type of ataxia due to loss of discriminative tactile sensibility contralateral to the thalamic lesion.