Thalamus and Limbic System Flashcards
Thalamic Relay (TR) Neurons
- located in thalamus
- receive input from sensory system
- relay sensory information to cortex via Glu in layer 4 of cortex
- ex. LGN and visual sense
- awake: ~-55mV, depolarized when neurons fire high frequency action potentials
- sleep: slow wave stage inhibits TR neurons by releasing GABA, ~85mV, fire in bursts of action on top of Ca++ spike (Ca spike happens with 3Hz frequency)
T Type Ca Channel
- voltage gated
- found in thalamic relay neuron
- has activation gate (closed at /80mV) and inactivation gate (open at -80mV)
- movement of gates is very slow
Optogenetics
- used in mouse models to control seizures
- channelrhodopsin: blue light opens and depolarizes cell
Dorsomedian (DM) Nucleus of Thalamus
-to frontal associated cortex
Anterior Nucleus of Thalamus
-to cingulate gyrus of cortex
VA/VL Nucleus of Thalamus
-to motor cortex
VPM/VPL Nucleus of Thalmus
-to somatosensory cortex
Pulvinar Nucleus of Thalamus
-to parieto-occipital associated cortex
LGN of Thalamus
- to visual cortex
- incoming optic tract
MGN of Thalamus
- to auditory cortex
- incoming inferior brachium
General Concepts of Thalamocortical Connections
- all connections are reciprocal
- R thalamus deals with L side of body and interacts with R cortex
Centromedian Nucleus of Thalamus
-motor
Reticular Nucleus of Thalamus
- a sheet of cells on lateral surface of thalamus
- primarily inhibitory interneurons with connections to all the other nuclei
Papez Circuit
- limbic system circuit
- memory
- mammilary body -> anterior n. -> cingulate gyrus -> hippocampus (all connected by fornix?)
Amygdala
- Limbic System Circuit
- emtion
- outputs: BNST, septal area, hypothalamus, thalamus
- involved in: fear, motivation, attention, sexual drive