Nuclei of the Brain

Hypothalamus

Function

Lesion

Mnemonics

H

Y

P

O

T

H

A

L

A

M

U

S

Anterior

Control parasympathetic – ↓temperature

Hyperthermia

 AC (anterior cooling)

Posterior

Control sympathetic – ↑ temperature

Poikilothermia (inability to control temperature)

& ipsilateral Horner

P for Poikilothermia

Medial

Satiety center

Obesity

Lateral

Hunger center, Thirst center

Weight loss & Starvation

Gas tank is lateral

Mammillary

Memory

Amnesia (Wernicke’s)

Suprachiasmatic

Controls circadian rhythm

Preoptic

Secretes GnRH

Supraoptic

Secretes ADH (vasopressin)

DI

Paraventricular

Secretes oxytocin, TRH, CRH

Arcuate

Secretes PIF

Thalamus

Function

Afferent

Efferent

T

H

A

L

A

M

U

S

Anterior

Attention & memory

Mammillary body

Cingulate gyrus

N

O

N

S

P

E

C

F

I

C

Medial Dorsal

Emotions & executive functions

Hypothalamus

Prefrontal cortex

Centro Medial (intralaminar)

Emotional content of pain

Slow pain pathway

Cortex

Pulvinar

Visual attention

Superior colliculus

Visual cortex

Reticular

Sensory inhibition

Generates sleep spindles

temporally inhibit sensory output from the thalamus so distracting sensations do not reach conscious awareness while attention is focused in another sensory modality.

Thalamic nuclei

Thalamic nuclei

Intralaminar

Arousal

Reticular formation

All cortex

VL, VI (intermediate)

Coordination of movements

Cerebellum & BG

Motor cortex

M

O

T

O

R

VA

Initiation & Planning of movement

BG

Premotor cortex

VPL

Somatic sensation

STT – ML

Sensory cortex

S

E

N

S

O

R

Y

VPM

Somatic sensation

Trigeminal nucleus

Sensory cortex

MGN

Hearing

Brachium of inf. colliculus

Auditory cortex

LGN

Vision

Optic tract

Visual cortex

Basal Ganglia nuclei

Summary of the Basal Ganglia

• Putamen and Caudate are the input nuclei
• GP is the main output nucleus.
• SNpc: sends dopaminergic fibers to Putamen
• STN: receive inhibitory fibers from GPe and send excitatory fibers to GPi.

Caudate

Play a role in:

– movement processing

– Cognitive executive functions

– working memory, learning and language.

 – Responds to visual beauty (neural correlate for romantic love)

Connections:

From dorsolateral prefrontal cortex  dorsolateral part of caudate  dorsomedial nucleus of thalamus  back to prefrontal cortex.

STN

Part of Indirect (inhibitory) loop of BG

(Send glutaminergic fibers to stimulate GPi)

lesion would cause hemiballismus – Impulsivity

GP

Input: from putamen, STN (no direct afferent from cortex)

Projects to: thalamus and STN

Other brain/brainstem nuclei

Amygdala

Part of limbic system, involved in memory, emotions and decision making.

Efferents go through 3 main pathways:

1-     Stria terminalis pathway (main pathway) from medial nucleus to nucleus of stria terminalis then to thalamus and hypothalamus.

2-     Amygdalofugal pathway: from lateral nucleus to thalamus (dorsomedial nucleus), hypothalamus, BG and brain stem.

3-     Anterior commissure pathway: to the opposite temporal lobe

Nucleus accumbens

Involved in anticipating reward and habit formation

Red nucleus

Motor coordination (mainly shoulder and upper arm), arm movements during walking, crawling (baby); movement initiation.

Locus ceruleus

Located in Pons. Involved in reaction to stress and panic, attention and memory. principal site for brain synthesis of norepinephrine

Nucleus basalis of Meynert

Located in basal forebrain, principal site for brain synthesis of Ach. Sends widespread projections to neocortex, lesion would cause marked decrease in mental capacity and learning as seen in Alzheimer and PD. 

Raphe nuclei

Located in the medial portion of the brainstem from medulla to pons. Major source for serotonin in the brain. Involved in sleep-wake cycle and circadian rhythm.