Welcome to the Edwards Lab!
Donald H. Edwards
Department of Biology
Georgia State University
Atlanta, GA 30302-4010
Tel: (404) 651-1645
FAX: (404) 651-2509
email: dedwards@gsu.edu
2005
Edwards/Derby Lab Picnic
Research
The Neural
Bases of Behavior
Dominance Hierarchy Formation
Synapses, Serotonin and Social Status
News Accounts
"Science Bits"
References
Coincidence Detection
Growth
and Neuronal Integration
Publications
List of
papers
Abstracts of
recent papers
Programs and Research Centers
Neuroscience at GSU
Center for Neural
Communication and Computation
Teaching
Bio 8010
Bio 8550
Bio 3840
Bio 8950
Research: The Neural Bases of Behavior
Our research concerns the mechanisms that govern behavior as they operate at
the level of molecules, synapses, neurons, networks and systems of the nervous
system, and with the interaction between the body and the world. The red
swamp crayfish Procambarus clarkii
has been the focus of our study, because of the animal’s broad repertory
of behavior and its easily accessible nervous system. In this, we follow after
Thomas Huxley (see The Crayfish: An
Introduction to Zoology), Sigmund Freud (“Ueber
den Bau der Nervenfasern und Nervenzellen beim Flusskrebs”,
Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, Wien,
85(1)-9-46, 1882), and Robert Yerkes (“Habit formation in the crawfish Camabrus
virilis (
Escape
Crayfish
escape from dangerous situations, including attack by predators and fights with
other crayfish, by making rapid flicks of the abdomen (see Fig.
1). These escapes are controlled by
three neural circuits named after sets of giant neurons that trigger them:
Lateral Giant (LG), Medial Giant (MG), and non-giant (NG), a circuit that lacks
giant neurons. The LG and MG neurons are
among the first neurons to be individually identified in any animal (Johnson,
J. Comp. Neurol. 36:323, 1924), and have provided a model of many areas of
neuroscientific inquiry ever since. The
LG is really a set of highly coupled neurons, one in each hemi-segment of the
abdomen, that form a ladder like network that functions like one neuron with
multiple input and output sites. The LG
is excited by a strong, sudden blow to the tail, like might occur during a
predator’s attack, and triggers a sudden jack-knife flip of the abdomen
that throws the animal up and forward (see the Fig. 1). The MG is a pair of neurons in the brain that
are excited by an attack to the front of the animal, and that evoke a quick
curling of the abdomen that throws the animal backward. The NG circuit is much less well defined; it
is excited by more gradual threats, and it triggers directed tail flip escapes
that carry the animal away from the direction of the threat.
Escape
from a predator Although it was clear from
the first studies of LG and MG (Johnson, 1924) that they triggered movements
appropriate for escape, it was only recently that we were able to show that
these neurons were used by the animals to trigger escape from a
predator’s attack. Jens Herberholz, a postdoc in the lab
(1999-2005) and Marjorie Sen, an undergraduate
researcher (2001-2005), videotaped the attacks of a dragonfly nymph on a
crayfish while recording the electrical potentials evoked in the aquarium by
the giant neurons and muscles of the crayfish.
These recordings allowed them to identify which circuit the attack had
excited, and to measure the efficacy of the escape it produced.
Dominance Hierarchy Formation
Social animals form hierarchies so as to divide resources without unnecessary
conflict. Conflict may occur at the outset, however, when two unfamiliar
animals meet, and they are of about equal size and strength. Then
agonistic interactions may escalate to full fighting. Usually these 
fights
are brief, and end when one animal suddenly withdraws. The new dominant
may pursue briefly, so as to 'pound in' the lesson of who won and who
lost. The sudden change in behavior, from fighting to retreat, is
indicative of a corresponding change in the brain about which we know very
little. We have found that in crayfish, this change in behavior is
reflected in the frequency with which several agonistic behaviors (approach,
attack, and offensive tailflip) and several defensive behaviors (retreat, three
forms of escape tailflip) are displayed (Herberholz et
al., 2001). Before the decision to withdraw by one animal, both
animals displayed similar patterns of attack and offensive tailflip,
accompanied by very few defensive behaviors. Suddenly one animal would
break contact and initiate a rapid series of tailflips that would carry it away
from the dominant. The tailflips were activated by two different neural
circuits, the 'medial giant' and 'non-giant' circuits, that trigger rearward
escapes in response to frontal attacks. The sudden release of these
tailflips indicates that the stimulus threshold for activating the circuits
must have changed from very high before the decision to withdraw to very low
thereafter. We don't yet know the mechanism for this transition, except
to say that both circuits are under strong inhibitory control; it is
likely that one consequence of the decision to withdraw is removal of that
inhibition. Interestingly, the lateral giant circuit (see below), which
triggers an upward tailflip escape in response to an attack from the rear, was
activated only once during fights between 8 pairs of animals, suggesting that
it is inhibited throughout such contests.
Synapses, Serotonin and Social Status. It has been known for some time that
serotonin, a psychoactive neurochemical implicated in the control of mood,
aggression, blood flow, and digestion, also affects the response of the lateral
giant (LG) neuron (picture at right) in crayfish to its normal sensory inputs (Glanzman and Krasne, 1983).
The LG neuron is excited by a tap on the tail that might occur when the animal
is attacked, and it triggers a tail flip escape response that moves the animal
quickly away from the stimulus (see picture above). Recently we found
that the effect of serotonin on LG's response depends on the social status of
the crayfish (Yeh, et al.,
1996; Yeh, et al., 1997).
Serotonin increases the responsiveness of the LG neuron in crayfish that have
been isolated for a month or more ("isolates"), and this increase
persists for several hours after the serotonin is removed. In social
subordinates, however, serotonin inhibits LG's response, whereas in social
dominants, LG's response is increased again. In these last two, the
effects of serotonin persist only as long as the drug is present.
Social hierarchies form
when unfamiliar animals get together (Issa et
al., 1999). The larger animal will usually become the dominant member
of the pair, with first choice of all the available resources (e.g., food,
shelter), whereas the smaller will become subordinate. Although the
social status of the two animals is decided within the first hour of pairing,
usually after a few brief bouts of fighting, the differences in the
effect of serotonin on LG's response take nearly two weeks to develop
fully. Other aspects of the animals' behavior changes gradually
during this period as they settle into their new social roles.
Should the subordinate be
reisolated, or should it be re-paired with another subordinate and become
dominant to that new animal, the inhibitory effect of serotonin will change to
the facilitatory effect characteristic of isolate or dominant
animals. Should a dominant animal be paired with and become
subordinate to another dominant animal, the effect of serotonin does not change
to that typical of the other subordinates. Rather it retains its
facilitatory character, even after more than a month of subordinate
status. These results suggest that if dominant status is the preferred
social state, then the facilitatory effect of serotonin is a preferred
physiological state.
Many different drugs activate
different classes of receptor molecules for serotonin in vertebrates.
When two of these were substituted for serotonin in the crayfish experiments,
one had inhibitory effects on LG's response in both dominant and subordinate
animals, and the other had facilitatory effects in both animals. These
and other data suggest that the changes in the effect of serotonin following a
change in social status resulted from changes in the receptors for
serotonin in the LG neuron.
This work is significant because it
is the first report that a change in an animal's social status can change the
population of molecular receptors for, and the effect of, a neurochemical
like serotonin in the nervous system. In view of this result, it
appears likely that the obvious difference in the behavior of dominant and
subordinate animals occurs in part because their nervous systems are different,
so that serotonin now has different effects in the two animals. This
suggestion is supported by recent behavioral experiments which showed that
LG-evoked tail flips become much more difficult to evoke in subordinate
crayfish than in dominant crayfish during a fight, when serotonin may be
naturally released in the nervous system (Krasne et al., 1997).
News Accounts of this Work. Several press accounts of this work
are available. These include:
- "Status goes to the brain", Science Bits cartoon by Donna Okino, The Boston Globe, March 11, 1996 (on the right).
- "Social Status Sculpts Activity in Crayfish Neurons" by Marcia Barinaga, Science 271: 290-291, (1996).
- "Serotonin and Crabby Behavior" by Christine Folz, Journal Watch for Psychiatry 2(3): 21-22 (1996).
- "Animal Watch: Chemistry and Status", by Rachel Preiser, Discover, July 1996, p. 34
- "Losers Get an Attack of
Nerves", by Alison Motley, New Scientist,
- "Crawdad War and Peace: The Nature Cafe Closes Shop" by Eddie Nickens, in "The Nature Cafe: Discovery Channel Online"
- "Macht geht auf die Nerven", in Focus, 8/1996, p. 130.
- "Social Rank Makes Brain
Act Fish", by Ron Haybron, in The Cleveland Plain Dealer,
- "Time to get up off the
couch?; Through the Eighties and Nineties, psychotherapy has reigned
supreme. Now, research suggests much mental illness may have
physical origins. Will the shrink soon be out of a job? Jerome
Burne reports" by Jerome Burne, The Independent (U.K.)
- "Crayfish fights trigger link to body changes" by Rachel Preiser, Discover Magazine, in The San Diego Union-Tribune, August 7, 1996, p. E-1.
- "Lobster's tale is a
salty saga of serotonin and social status" by Tom Siegfried, The
Dallas Morning News, 7D,
· Glanzman, D.L. and Krasne, F.B. Serotonin and octopamine have opposite modulatory effects on the crayfish's lateral giant escape reaction. J Neurosci 3:2263-2269, 1983.
· Krasne, F.B., Shamasian,
A., and Kulkarni, R. Altered excitability of the crayfish lateral giant escape
reflex during agonistic encounters. J.Neurosci. 17(2):692-699, 1997.
(Return to Contents)
Coincidence Detection. Coincidence detection is important for functions as diverse as Hebbian learning, binaural localization, and visual attention. We have found that extremely precise coincidence detection is a natural consequence of the normal function of rectifying electrical synapses (Edwards et al., 1998). Such synapses open to bidirectional current flow when presynaptic cells depolarize relative to their postsynaptic targets, and remain open until well after completion of presynaptic spikes. When multiple input neurons fire simultaneously, the synaptic currents sum effectively and produce a large EPSP. However, when some inputs are delayed relative to the rest, their contributions are reduced by the early EPSP and by postsynaptic current shunts through junctions already opened by the earlier inputs. These mechanisms account for the ability of the lateral giant neurons of crayfish to sum synchronous inputs, but not inputs separated by only 100 msec. This coincidence detection enables crayfish to produce reflex escape responses only to very abrupt mechanical stimuli. In light of recent evidence that electrical synapses are common in the mammalian CNS, the mechanisms of coincidence detection described here may be widely used in many systems. (Return to Contents)
Growth and Neuronal Integration. Neurons must
work both when they are small in young animals and when they are larger in
adult animals. The increase in size that neurons experience, however,
changes the way in which electrical current flows through them, and so changes
they way in which they respond to synaptic inputs. We have found
that two sets of giant neurons, one in cricket and one in crayfish, exemplify
two different patterns of neuronal growth that have different effects on
neuronal integration. The medial giant interneurons (MGI) in cricket
maintains its response properties as it grows. It grows approximately
uniformly, but such that the diameters of its processes increase as the square
of their increase in length (Hill et al., 1994).
The lateral giant (LG) neuron in crayfish becomes more of a low-pass filter as
it grows, which causes it to switch input circuits and become susceptible to
response habituation. It grows approximately isometrically (Edwards et
al., 1994a, b) . A cable
analysis of these different patterns of uniform growth indicates that,
regardless of the initial shape or distribution of active and passive membrane
properties, a cell that grows uniformly and with neurite diameters increasing
as the square of their increase in length will not change the way voltage is
distributed through the cell (Olsen et
al., 1996). This "isoelectrotonic" pattern of growth will enable
a synaptic potential created at corresponding positions in the small and large
cells to evoke identical responses at all other corresponding points in the two
cells. Conversely, uniform isometric growth causes the cell to become
electrically larger, and to become a low-pass filter. These analytical
results account for the different effects of growth on the two cells, in which
MGI grows isoelectrotonically, and LG grows isometrically. (Return
to Contents)
Review of this Work.
Marder, Eve Electrical Synapses: Beyond Speed and Synchrony to
Computation. Current Biology. (in press)
Recent Lab Publications
(for reprints, contact dedwards@gsu.edu)
Papers
· Song,
C.-K., Herberholz, J. and Edwards, D.H. (2006) The effects of social experience
on the behavioural response to unexpected touch in crayfish. J. Exp. Biol. 209: 1355-1363
· Antonsen, B. and Edwards, D.H. (2003) Differential dye-coupling reveals the lateral giant escape circuit in crayfish. J. Comp. Neurol. 466: 1-13.
· Herberholz, J., Antonsen, B.L. and Edwards, D.H. (2002) A lateral excitatory network in the escape circuit of crayfish. J. Neurosci. 22: 9078-9085.
·
Herberholz, J., Issa, F.A., and Edwards, D.H.
(2001) Patterns of neural circuit activation during dominance hierarchy
formation in freely behaving crayfish. J. Neurosci. 21: 2759-2767.
· Herberholz, J., Issa, F. A., Edwards, D. H. (2001). Patterns of Neural Circuit Activation and Behavior during Dominance Hierarchy Formation in Freely Behaving Crayfish. J. Neurosci. 21: 2759-2767
· Edwards, D.H., Heitler, W.J., and Krasne, F.B. (1999) Fifty years of a command neuron: The neurobiology of escape in crayfish. Trends In Neurosci. 22(4): 153-161.
· Heinrich, R., Cromarty, S.I., Hörner, M., Edwards, D.H., and Kravitz, E.A. (1999) Autoinhibition of serotonin cells: An intrinsic regulatory mechanism sensitive to the pattern of usage of the cells. Proc. Nat. Acad. Sci. U.S.A. 96: 2473-2478.
· Issa, F.A., Adamson, D.J., and Edwards, D.H. (1999) Dominance hierarchy formation in juvenile crayfish, Procambarus clarkii. J. Exp. Biol. 202: 3497-3506.
· Katz, P. S. and Edwards, D.H. 1999
Metamodulation: the control and modulation of neuromodulation. In: Beyond
Neurotransmission: Neuromodulation and its importance for information
processing, edited by P. S. Katz,
· Edwards, D.H. The effects of neuronal growth
and social experience on the development of behavioral plasticity. In: The
Biology of Early Influences, Ed. F. Johnson, Plenum Press,
· Edwards DH, Yeh S-R, and Krasne FB. (1998) Neuronal coincidence detection by voltage-sensitive electrical synapses. Proc. Nat. Acad. Sci. USA 95: 7145-7150.
· Heitler W.J. and Edwards, D.H. (1998) Effect of temperature on a voltage-sensitive electrical synapse in crayfish. J. Exp. Biol. 201: 503-13
· Edwards, D.H. and Kravitz, E.A. (1997) Serotonin, social status and aggression. Curr. Opin. Neurobiol. 7: 811-819.
· Hörner M, Weiger WA, Edwards DH, Kravitz EA (1997) Excitation of identified serotonergic neurons by escape command neurons in lobsters. J Exp Biol 200: 2017-33
· Yeh S-R, Musolf BE, Edwards DH (1997) Neuronal adaptations to changes in the social dominance status of crayfish. J Neurosci. 17:697-708.
· Olsen O, Nadim F, Hill AA, Edwards DH (1996) Uniform growth and neuronal integration. J Neurophysiol 76: 1850-7
· Yeh S-R, Fricke RA, Edwards DH (1996) The effect of social experience on serotonergic modulation of the escape circuit of crayfish. Science 271:366-369.
· Edwards DH, Fricke RA, Barnett LD, Yeh S, Leise EM (1994) The onset of response habituation during the growth of the lateral giant neuron of crayfish. J Neurophysiol 72:890-898.
· Edwards DH, Yeh S-R, Barnett LD, Nagappan PR (1994) Changes in synaptic integration during the growth of the lateral giant neuron of crayfish. J Neurophysiol 72:899-908.
· Hill AAV, Edwards DH, Murphey RK (1994) The effect of neuronal growth on synaptic integration. J Comput Neurosci 1:239-254.
· Edwards DH (1991) Mutual inhibition among neural command systems as a possible mechanism for behavioral choice in crayfish. J Neurosci 11:1210-1223.
· Edwards DH, Heitler WJ, Leise EM, Fricke RA (1991) Postsynaptic modulation of rectifying electrical synaptic inputs to the LG escape command neuron in crayfish. J Neurosci 11:2117-2129.
· Heitler WJ,
Fraser K, Edwards DH (1991) Different types of rectification at electrical
synapses made by a single crayfish neurone investigated experimentally and by
computer simulation. Journal of Comparative Physiology A 169:707-718.
(Return to Contents)
Full
Citations of Recent Papers
Edwards, D.H., Yeh, S.-R., and Krasne, F.B. (1998) Neuronal
coincidence detection by voltage-sensitive electrical synapses.
Proc. Nat. Acad. Sci. USA 95: 7145-7150..
Abstract. Coincidence detection is important
for functions as diverse as Hebbian learning, binaural localization, and visual
attention. We show here that extremely precise coincidence detection is a
natural consequence of the normal function of rectifying electrical
synapses. Such synapses open to bidirectional current flow when
presynaptic cells depolarize relative to their postsynaptic targets, and remain
open until well after completion of presynaptic spikes. When multiple
input neurons fire simultaneously, the synaptic currents sum effectively and
produce a large EPSP. However, when some inputs are delayed relative to
the rest, their contributions are reduced by the early EPSP and by postsynaptic
current shunts through junctions already opened by the earlier inputs. These
mechanisms account for the ability of the lateral giant neurons of crayfish to
sum synchronous inputs, but not inputs separated by only 100 msec. This
coincidence detection enables crayfish to produce reflex escape responses only
to very abrupt mechanical stimuli. In light of recent evidence that
electrical synapses are common in the mammalian CNS, the mechanisms of
coincidence detection described here may be widely used in many systems.(Return)
Hörner M,
Abstract. Serotonin-containing neurosecretory
neurons in the first abdominal ganglion (A1 5-HT cells) of the lobster (Homarus
americanus) ventral nerve cord have been shown previously to function as 'gain
setters' in postural, slow muscle, command neuron circuitries. Here we show
that these same amine neurons receive excitatory input from lateral (LG) and
medial (MG) giant axons, which are major interneurons in phasic, fast muscle
systems. Activation of either LG or MG axons elicits short-latency,
non-fatiguing, long-lasting excitatory postsynaptic potentials (EPSPs) in A1
5-HT cells which follow stimulus frequencies of up to 100 Hz in a 1:1 fashion.
Single spikes triggered in either giant axon can produce EPSPs in the A1 5-HT
cells of sufficient magnitude to cause the cells to spike and to fire additional
action potentials after variable latencies; action potentials elicited in this
way reset the endogenous spontaneous spiking rhythm of the A1 5-HT neurons. The
giant-axon-evoked EPSP amplitudes show substantial variation from animal to
animal. In individual preparations, the variation of EPSP size from stimulus to
stimulus was small over the first 25 ms of the response, but increased
considerably in the later, plateau phase of each response. When tested in the
same preparation, EPSPs in A1 5-HT cells evoked by firing the LG axons were
larger, longer-lasting and more variable than those triggered by firing the
MGs. Firing A1 5-HT cells through an intracellular electrode, prior to
activation of the giant fiber pathway, significantly reduced the size of
LG-evoked EPSPs in A1 5-HT cells. Finally, morphological and physiological
results suggest that similarities exist between giant fiber pathways in
lobsters and crayfish. The possible functional significance of an involvement
of these large amine-containing neurosecretory neurons in both tonic and phasic
muscle circuitries will be discussed. (Return)
Yeh SR, Musolf BE, Edwards DH 1997 Neuronal
adaptations to changes in the social dominance status of crayfish. J. Neurosci.
Jan 15 17:2 697-708
Abstract
The effect of superfused serotonin (5-HT; 50 mM)
on the synaptic responses of the lateral giant (LG) interneuron in crayfish
was found to depend on the social status of the animal. In socially isolated
animals. 5-HT persistently increased the response of
LG to sensory nerve shock. After social isolates were paired in a small cage,
they fought and determined their dominant and
subordinate status. After 12 d of pairing, 5-HT reversibly inhibited the
response of LG in the social subordinate and reversibly
increased the response of LG in the social dominant crayfish. The effect of
5-HT changed approximately linearly from response enhancement to inhibition in
the new subordinate over the 12 d of pairing. If, after 12 d pairing, the
subordinate was reisolated for 8 d, the response enhancement was restored. If
the subordinate, instead, was paired with another subordinate and became
dominant in this new pair, the inhibitory effect of 5-HT changed to an
enhancing effect over the next 12 d of pairing. If, however, two dominant
crayfish were paired and one became subordinate, the enhancing effect of 5-HT
persisted in the new subordinate even after 38 d pairing. These different
effects of serotonin result from the action of two or more molecular receptors
for serotonin. A vertebrate 5-HT, agonist had no effect on social isolates but
reversibly inhibited the response of LG in both dominant and subordinate
crayfish. The inhibitory effects of the agonist developed approximately
linearly over the first 12 d of pairing. A vertebrate 5-HT2 agonist
persistently increased the response of LG in isolate crayfish and reversibly
increased the response of the cell in dominant and subordinate crayfish.
Finally, although neurons that might mediate these effects of superfused 5-HT
are unknown, one pair of 5-HT-immunoreactive neurons appears to contact the LG
axon and initial axon segment in each abdominal ganglion in its projection
caudally from the thorax.
Yeh SR, Fricke RA,
Edwards DH 1996 The effect
of social experience on serotonergic modulation of the escape circuit of
crayfish. Science 271:5247 366-9
Abstract The neuromodulator serotonin has
widespread effects in the nervous systems of many animals, often influencing
aggression and dominance status. In crayfish, the effect of serotonin on the
neural circuit for tailflip escape behavior was found to depend on the animal's
social experience. Serotonin reversibly enhanced the response to sensory
stimuli of the lateral giant (LG) tailflip command neuron in socially dominant
crayfish, reversibly inhibited it in subordinate animals, and persistently
enhanced it in socially isolated crayfish. Serotonin receptor agonists had
opposing effects: A vertebrate serotonin type 1 receptor agonist inhibited the
LG neurons in dominant and subordinate crayfish and had no effect in isolates,
whereas a vertebrate serotonin type 2 receptor agonist enhanced the LG neurons'
responses in all three types of crayfish. The LG neurons appear to have at
least two populations of serotonin receptors that differ in efficacy in
dominant, subordinate, and socially isolate crayfish. (return)
Olsen O, Nadim F, Hill AA, Edwards
DH 1996 Uniform growth and neuronal integration. J Neurophysiol. 76:1850-7
Abstract. The cable equations
were analyzed to determine the effects of two patterns of uniform growth on the
passive and active integrative properties of neurons. 2. During uniform
isoelectrotonic growth, the diameters of all neuronal processes increase as the
square of their increase in length, while the specific electrical properties
and branch terminal conditions of the neuron remain constant. An analytic
inductive proof is given to show that, for any neuron, uniform isoelectrotonic
growth increases the input conductance everywhere by the cube of the growth
factor, but leaves the active and passive spread of membrane potential within
the neuron unchanged. The spread of membrane voltage is unchanged because this
pattern of growth enables both the axial and membrane currents everywhere in
the cell to increase by the cube of the growth factor. Synaptic inputs would
evoke the same responses in the isoelectrotonically larger cell as in the
smaller cell if the total postsynaptic conductance of the synapse increased
with the dendritic membrane area. 3. During uniform isometric growth, the
diameter and lengths of all processes increase by the same factor, while the
specific electrical properties and branch terminal conditions remain constant.
This pattern of uniform growth increases the input conductance by the square of
the growth factor, and also increases the attenuation, delay, and low-pass
filtering of the cell's responses. Voltage attenuation increases with isometric
growth because the axial current increases in proportion to growth, while the
membrane current increases in proportion to the square of the growth factor.
Isometric growth reduces the ability of distal synaptic inputs to affect the
membrane potential at proximal integrating sites, even after the synaptic
conductance has increased to compensate for the increased input conductance. 4.
These two patterns of uniform growth help define the consequences of all types of
uniform growth for neuronal integration and responsiveness. (Return)
Past and present lab members and current addresses:
Dr.
Jens Herberholz: Assistant Professor, Department of Psychology, Univ.
Dr. Esther Leise: Associate
Professor, Department of Biology, Univ.
Dr. Marc Weissburg: Associate
Professor,
Dr. Shih-Rung Yeh: Assistant
Professor,
Dr. Cliff Opdyke
Dr. Ted Simon, USEPA,
Dr. Brian Antonsen, Department of
Biology,
Dr. Jeffrey Triblehorn, Department
of Biology,
Dr. Jo Drummond, Astrazenica Corp., Melbourne, AU
Dr. Cha-Kyong Song, Department of Life Science, Ewha Womans University, Seoul, 120-750, Korea
Dr. Linda Anderson
Dr. Peri Naggapan
Ms. Barbara Musolf, Assist.
Professor, Dept. Biology,
Ms. Marjorie
Sen, Neuroscience Graduate Program,
Ms. Elizabeth DeGoursac,
Neuroscience Graduate Program,
Mr. Fadi Issa, Department of
Biology,
Ms. Nadja Spitzer, Department of
Biology,
Mr. David Cofer, Department of
Biology,
Ms. Laurel Johnstone
Mr. Jianyang Shi
Edwards/Derby/Guest
Lab Picnic 2005:
Front row: Barbara Musolf, Marjorie Sen, Nadja Spitzer, Kody, Laurel Johnstone, Don Edwards
2nd row: Emily Herberholz, Marjorie’s mom, Jack Edwards, Marly
3rd row: Brian Antonsen, Fadi (‘Pete’) Issa, Malcolm’s friend Mackenzie, Merry Clark, Katherine Herberholz, Katelyn Herberholz, Amy Horner
4th row: Catherine’s friend, Catherine McCurdy, Jeff Triblehorn, Malcolm Johns, Jeff Johnson, Cole Dickerson, Manfred Schmidt, Chuck Derby, Jens Herberholz
last modified:
Comments? contact: dedwards@gsu.edu