Functional anatomy: dynamic states in basal ganglia circuits
Functional Anatomy of the Basal Ganglia · Functional Anatomy of the Basal Ganglia • Four main...
Transcript of Functional Anatomy of the Basal Ganglia · Functional Anatomy of the Basal Ganglia • Four main...
Functional Anatomy of the Basal Ganglia• Four main nuclei
striatum, globus pallidus, subthalamic nucleus, & substantia nigra
• Two general frameworks– Anatomically-based physiological models
• Direct vs indirect pathway controling motor output– Systems/behavioral level
• Functional classification according to behavioral distruption caused by focal lesions
– Parallel Cortico-BG-cortical loops• Major inputs: neocortex & substantia nigra• Major output: neocortex via thalamus
Overview: Basal Ganglia & thalamus
Herrero et al (2002) Figure by MIT OCW.
Striatum = Caudate nucleus and putamenPallidum = Ext. and Internal segments of globus pallidus
Cerebral Cortex
Caudate
Putamen
Globus Pallidus
(Substantia Nigra)
Hippocampus
Amygdala
White Matter
Midbrain dopamine InputsSN: Substantia NigraVTA: ventral tegmental areaSC: sup. ColliculusRD: red nucleus Section of brainstem
stained for tryosinehydroxilase (DA)
Glutamate Input:Cortex
Organizing principlesProximity
Topograpic projections from motor/somatosensory cortices to putamen
LongitudinalTrans-striatal projections from association cortices to caudate
Tripartate pattern
Saint-Cyr (2003) J. Int. Neuropsych. Soc.Figure by MIT OCW.
Tripartate input/output organization“The neurologist’s, psychologist’s & psychiatrist’s basal ganglia” (Saint-Cyr, 2003)
Neurologists movement disorders Psychologists cognitive operationsPsychiatrists behavioral & emotional disorders
Nakano et al. (2000)
CN
CN
Put
IC
GPe
GPi
STN
CM
PfVAmc
VApc
VLo
Motor
Associative
Limbic
Figure by MIT OCW.
Multiple parallel loop model• Alexander et al (1986) proposed as many as five
separate cortico-BG-cortical circuits
1. Motor2. Oculomotor3. Cognitive4. Lateral frontal5. Emotional
• Complete segregation unlikely given anatomy• Main point: The basal ganglia isn’t just a motor
structure
Middleton & Strick (2000)
Cognitive Sensory
Planning,workingmemory
Spatialworkingmemory
Objectworkingmemory
Visualrecognition,
discrimination
9 46 12 TE
VApcVAmc VAmcVApc
MDmfVAmcMDmf
VAmcMDmf
GPi GPi GPiGPi
SNprGPi
SNprSNpr SNprSNpr
M1 SMA PMv FEF
VLo VLo VLoVLm
Movementparameters
Internally-guided
movements
Externally-guided
movements
EyeMovements
Skeletomotor Oculomotor
Function
Corticalarea
Thalamicnucleus
Outputnucleus
Figure by MIT OCW.
Major Output:Thalamus
Herrero et al (2002)
MAJOR OUTPUT: Thalamus
SomatosensoryCortex
Motor Cortex
Premotor Cortex
Prefrontal
Primary Visual Cortex
Primary Auditory Cortex
Cingulate Gyrus
Central Sulcus
Calcarine Sulcus
I
MD
VA
VLa
VLp
VPL
MGNLGN
Pulv
Figure by MIT OCW.
Basic Neuropathology
Dauer & Przedborski (2003)Figure by MIT OCW.
Lewy Bodies
• Intraneuronal inclusions• Stain positively for synuclein & ubiquitin• Found in SN, locus coeruleus, nucleus basalis,
cerebral cortex, & olfactory bulb
Cortico-BG-Cortical Circuitry
Herrero et al (2002)
SO+SI SO+SI
STN STN
Met-Enk Met-Enk
PutPut
GPe GPe
GPi GPi
SPSP
DA
Cerebral Cortex Cerebral Cortex
DA
D2
SNpc
SNpr SNpr
SNpc
D1D1
D2
CONTROL PARKINSONIAN SYNDROME
+
++
+
_
_
_
_
_
Figure by MIT OCW.