Basal nuclei : lecture notes

 

Basal nuclei

Terminology related to basal nuclei

Nerurological structure	Basal nuclei
Corpus striatum	Caudate nucleus + lentiform nucleus
Amygdala	Amygdaloid nucleus
Claustrum	Claustrum
Neostriatum	Caudate nucleus +putamen
Paleostriatum	Globus pallidus
Caudate nucleus	Caudate nucleus
Lentiform nucleus	Globus pallibus +putamen

 

Basal nuclei

•        They are the large masses of grey matter situated within the white core of each cerebral hemisphere

•        They form essential part of extra pyramidal system

•        Parts :

1. Corpus striatum : it has two parts

•        caudate nucleus:  neostriatum : relatively new

•        Lentiform nucleus : it has two part i) globus pallidus (paleostriatum: relatively ancient) ii) putamen: neostriatum : relatively new ) 

2. Claustrum

3. Amygdaloid body

Corpus striatum

•        It is situated lateral to the thalamus

•        It is formed by caudate nucleus and lentiform nucleus

•        Internal capsule, a band of nerve fibres divide the lentiform nucleus and caudate nucleus

Caudate nucleus

•        It is a comma shaped grey matter surround thalamus

•        Parts : head, body and tail

•        Amygdaloid body attached with terminal end of tail of caudate nucleus

Lentiform nucleus

•        It is a lens shaped grey matter

•        It forms lateral boundary of internal capsule

•        It has two part :

    i) globus pallidus (paleostriatum: relatively ancient)

     ii) putamen: neostriatum : relatively new )

Claustrum

•        It is a thin saucer shaped mass of grey matter

•        It is situated between putamen and insula 

Amygdaloid body

•        It is an almond shaped mass of grey matter in the temporal lobe

•        It is situated deep to uncus

•        Developmentally it is related to basal nuclei but functionally it is included in the limbic system

Connection of corpus striatum

•        Afferent fibres come from cortex, thalamus , substantia nigra

•        Efferent fibres goes to mainly in globus pallibus

•        Fibres of globus pallidus goes to thalamus

Function of basal nuclei

1. Regulate muscle tone
2. smoothening the voluntary motor activities of the body
3. Control automatic associated movements like swinging of arms during walking

Disorders of the basal ganglia

•        Disturbance of muscles tone

•        Unwanted involuntary movement

•        Name of disease: parkinsonism :

•        Resting tremors ( pill rolling tremor)  : diminished during movement

•        Loss of facial expression

•        Shuffling gait

•        Cogwheel type of muscular rigidity