Summer Undergraduate Research Program - Fred Hutchinson ...

Uncovering the Neural Circuitry in Fear
Joshua Onyango 1 Kunio Kondoh 2 and Linda B. Buck 2
2012 Best Poster Presentation Award
Results cont’d
Methods
Abstract
Figure 2: CRHiresCre Mice
changes mediated by the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is activated
by the release of corticotropin releasing hormone (CRH) from CRH neurons in the paraventricular
nucleus (PVN) of the hypothalamus. CRH causes secretion of adrenocorticotropic hormone
cortex. Previous studies have linked dysregulation of the HPA axis to a number of human
responses as well as human health. The mechanisms and neural circuits that regulate the HPA
axis are still unclear. To obtain anatomical and molecular insight into regulatory mechanisms in
retrogradely through chains of connected neurons to infect neurons upstream of CRH neurons.
The virus-infected neurons were analyzed for their locations and for markers of excitatory or
hybridization to detect markers of excitatory glutamatergic or inhibitory GABAergic inhibitory
hypothalamus that are upstream of CRH neurons and express a marker of excitatory neurons.
regulating the HPA axis.
Cre-dependent
PRV
Retrograde transport
PVN
CRH neuron
(Cre expression)
Introduction
Figure 3: Bartha Strain of PRV
-
113
Figure 6: Neurons likely to be directly upstream of CRH neurons
hybridization were analyzed. Virus-infected cells (HA+) and
SCh
Scp
SPa
hypothalamus
StA
SubC
SubI
SuMM
TC - Tuber cinerium area
Tz - Nucl of the trapezoid body
VDB - Nucl of the vertical limb of the
diagonal band
VMH - Ventromedial hypothalamic nucl
VMPO - Ventromedial preoptic nucl
MPA/O - Medial Preoptic area/nucl
Mtu - Medial tuberal nucl
PAG/Dk
PH - Posterior hypothalamic area
Pir - Piriorm cortex
PM - Premammillary nucl
PnC
part
PS - Parastrial nucl
Pv - Periventricular ber system
PV - Paraventricular thalamic nucl
PVN - Paraventricular Nucl
RCh - Retrochiasmatic area
Re - Reuniens thalamic nucl
Fi -
HDB - Nucl of the horizontal limb of
diagonal band
InC
LA - Lateroanterior hypothalamic nucl
LDTg - Laterodorsal tegmental nucl
LH - Lateral hypothalamic area
LPB - Lateral parabrachial nucl
LPGi - Lateral paragigantocellular nucl
LS
MA3 - medial accesory oculomotor nucl
Me5 - Mesencephalic trigeminal nucl
Maopt - Medial accesory optic tract
MeA - Medial amygdaloid nucleus
MnPO - Median preoptic nucl
Abbreviations
AcB -Acumbens nucleus
ADP - Anterodorsal preoptic nucl
AH - Anterior hypthalamic area
AMP - Anteromedial thalamic nucl
Arc - Arcuate hypothalamic nucl
AVPe - Anteroventral periventricular
nucl
BL - Basolateral amygdaloid nucl
BM - Basomedial amygdaloid nucl
BST
DM
nucl
DRI
DTM
nucl
EW
increased heart rate and cognitive alertness.
- An understanding of the characteristics of neural inputs to the CRH neurons in
mice could lead to a better understanding of the neural circuits involved in fear.
This knowledge could also reveal information relevant to the HPA axis and
stress-related pathologies in humans.
connections to the CRH neurons and whether neurons upstream of CRH neurons are likely to
transmit excitatory or inhibitory signals to CRH neurons.
-
stream neurons.
Conclusions
Figure 4: A Flowchart of the procedures used for the experiments;
neurons in the virus-infected neurons.
Neurons likely to be directly upstream of CRH neurons are detected in a number of regions
of the hypothalamus
The number of virus-infected neurons was low. More experiments are therefore needed
to draw conclusions.
(Vglut+) glutamatergic neurons.
Results
HA+ Vglut 1/2+ Merge (HA+ Vglut+)
Acknowledgments
binase
in order to replicate and
mice (CRHiresCre mice) that
exress Cre recombinase in CRH
studies from the Buck Lab
suggest that direct presynaptic
connections to the CRH neurons
CRH Neurons
(PVN)
CRH
Pituitary
ACTH
Adrenal
Cortex
HA+
Corticosteroids
Physiological changes
References
Figure 1: HPA Axis
from the pituitary causes the release of cortisol (humans)/ corticosterone (mice) from the adrenal cortex. These hormones lead to
physiological changes associated with fear.
Figure 5:
To determine if neurons upstream of CRH neurons express markers of
excitatory glutamatergic neurons or inhibitoryGABAergic neurons.
Objective: