Transcript Subcortical Neuroanatomy Russell M. Bauer, Ph.D. University of Florida January 23, 2006

Subcortical Neuroanatomy
Russell M. Bauer, Ph.D.
University of Florida
January 23, 2006
We will cover…
• Limbic System
• Subcortical circuits involving basal
ganglia
• Thalamocortical circuitry relevant to
cognition
Limbic System
Cingulate gyrus
Amygdala
Fornix
Septum
Mammillary body
Olfactory bulb
Two Limbic Circuits
Anterior
Thalamus
Cingulate
Gyrus
Dorsomedial
Thalamus
Mamillothalamic
Tract
Mammilary
Bodies
Orbitofrontal
Amygdalofugal
pathways
Fornix
Uncus
Hippocampus
Amygdala
PRPH
Medial (Papez)
Lateral
Bauer, Grande, & Valenstein, 2003
Thalamus
Blumenfeld, 2002
Blumenfeld, 2002
Blumenfeld, 2002
Basal Ganglia
Lateral view
Blumenfeld, 2002
ventral striatum
Anterolateral view
Blumenfeld, 2002
Basal Ganglia
• Caudate + Putamen = Striatum
• Putamen + Globus Pallidus = Lenticular
nucleus
• Subthalamic Nucleus
• Substantia Nigra
• Nucleus accumbens and ventral
pallidum also considered part of BG
Integrated Subcortical
Circuitry
General Organization of Frontal corticalstriatal-pallidal-thalamic-cortical loops
Blumenfeld, 2002
Blumenfeld, 2002
Blumenfeld, 2002
Dorsolateral (Prefrontal) Loop
• Critical for executive
function
• Damage produces
– Inflexibility
– Planning
– Problem-solving
– Goal-directed
behavior
Orbitofrontal (Limbic) Loop
• Involved in social
and emotional
functioning
• Damage produces:
–
–
–
–
–
Disinhibition
Hyperactivity
Emotional lability
Aggressiveness
Reduce selfawareness
Phineas Gage
(1823-1861, accident in 1848)
Phineas Gage’s lesion reconstructed
(H. Damasio and R. Frank, 1992)
Medial Frontal/Cingulate Loop
• Important in
behavioral activation
• Damage results in
– Akinetic mutism
– Abulia
– Impairments in
spontaneous
initiation of behavior
(Burruss, et. al., Radiology, 2000)
Motor Activation/Preparation
Heilman, Watson, & Valenstein, 2003
Selective Engagement and Disengagement of Cortex
Thalamus
A
E
G
Cortex
B
F
C
D
J
I
H
Nucleus Reticularis
Excitatory cortical projections to the thalamus (A) course through the nucleusreticularis (NR) sy napsing on inhibitory thalamic
interneurons (B), reticulo-thalamic neurons (C), and prov iding arborizing collaterals (D). The direct cortical projection to the thalamic
interneuron (B) results in the inhibition of thalamo-cortical projection (E). This inhibition of thalamo-cortical projections results in the
disengagement (inhibition) of select cortical areas. The reticulo-thalamic neuron (C) sy napses on, and inhibits, a thalamic interneuron
(F), resulting in excitation of thethalamo-cortical neuron (G). This excitation of thethalamo-cortical projection results in the engagement
of select cortical areas. The collateral (D) sy napses on, and inhibits, areticulo-thalamic neuron (H) which sy napses on a thalamic
interneuron (I). The thalamic interneuron (I) inhibits the thalamo-cortical neuron (J) resulting in the disengagement of select cortical
areas.
= Glutamatergic (excitatory )
= GABA-ergic (inhibitory )
Dashed lines represent inhibited neuron (neuron unable to exert it ’s inf luence on downstream neuron).
Selective Engagement
(Nadeau & Crosson, 1997)