bluuebunny/crossref_metadata_2025 huggingface dataset:
Fetal Dopaminergic Neurons Transplanted to the Normal Striatum of Neonatal or Adult Rats and to the Denervated Striatum of Adult Rats
Authors: Sable Vandana , Sailaja K. , Gopinath Gomathy , Tandon P. N.
Published: March 2007

Fetal ventral mesencephalon from the 15th gestational day was grafted into the striatum of neonatal and adult rats. In one group of adult rats, fetal nigra was transplanted into normal striatum. In a second group, the tissue was transplanted at sites where dopaminergic fibers were denervated with 6‐hydroxydopamine. The behavior of the dopaminergic neurons and glial reactions were studied by staining with cresyl violet to localize the transplants and by immunolabeling tyrosine hydroxylase (TH) and glial fibrillary acidic protein. In normal adults,
the transplants were small. At the edge of the transplants, TH‐positive neurons were packed into clusters, and an interface without any
significant crossover of TH‐positive fibers was present. Glial reaction was minimal in and around the transplant. In the denervated
striatum, transplants were generally larger than those in normal striatum and surrounded by a glial scar. TH‐positive neurons were both closely
packed and loosely arranged at the periphery of the transplants. Processes could be clearly defined and could be traced to the adjacent host striatum through the TH‐free denervated area. In neonates, the transplants were large and at times extended beyond the striatum. Most TH‐positive neurons were arranged linearly along the periphery of the transplant. Cell bodies were widely separated and a well‐developed neuropil was present. Fibers from the transplant mingled freely with the host striatum without any interface. In all three transplant groups, tracing the TH‐positive neurites was easy because they were thicker and coarser than other elements. No apparent glial reaction occurred in the neonates. Thus, the growth and maturation of dopaminergic neurons seemed to vary in different environments. The most conducive environment appears to be neonatal brain in which growth factors are readily available.
Apolipoprotein E Antibodies Affect the Retention of Passive Avoidance Memory in the Chick
Authors: Lancashire Chris , Mileusnic Radmila , Rose Steven P.R.
Published: March 2007

Isoforms of apolipoprotein E (ApoE) have been implicated as risk factors in Alzheimer’s disease. We have, therefore, examined the possible role of ApoE in memory formation, using a one‐trial passive avoidance task in day‐old chicks. Birds were trained on the task and
then at various times pre or post‐training were injected intracerebrally with anti‐ApoE. Immunofluorescence staining demonstrated the
presence of the antibody bound to the neuropil, close to the injection site and adjacent to the ventricle, with a residence time in the brain of
up to 30 min. Chicks that were injected 30 min pre‐training or just post‐training with 5μg/ hemisphere of the antibody learned the task, but
were amnesic when tested at 30 min or at subsequent times up to 24 hr Post‐training. When tested at 24 hr, birds injected 5.5 hr post‐training
showed unimpaired retention. Birds injected with 5μg/hemisphere of anti‐ApoA‐I (which has a brain distribution similar to that of
anti‐ApoE) at 30 min pretraining showed no amnesia, indicating the specificity of the effect to the ApoE. Possible mechanisms for this effect
are discussed.
The Role and Mechanisms of Action of Glucocorticoid Involvement in Memory Storage
Authors: Sandi Carmen
Published: March 2007

Adrenal steroid hormones modulate learning and memory processes by interacting with specific glucocorticoid receptors at different
brain areas. In this article, certain components of the physiological response to stress elicited by learning situations are proposed to form an
integral aspect of the neurobiological mechanism underlying memory formation. By reviewing the work carried out in different learning models in chicks (passive avoidance learning) and rats (spatial orientation in the Morris water maze and contextual fear conditioning), a role for brain corticosterone action through the glucocorticoid receptor type on the mechanisms of memory consolidation is hypothesized. Evidence is also presented to relate post‐training corticosterone levels to the strength of memory storage. Finally, the possible molecular mechanisms that might mediate the influences of glucocorticoids in synaptic plasticity subserving long‐term memory formation are considered, mainly by focusing on studies implicating a steroid action through (i) glutamatergic transmission and (ii) cell adhesion molecules.
Passive Avoidance Training and Recall are Associated With Increased Glutamate Levels in the Intermediate Medial Hyperstriatum Ventrale of the Day‐Old Chick
Authors: Daisley Jonathan N. , Gruss Michael , Rose Steven P. R. , Braun Katharina
Published: March 2007

In the young chick, the intermediate medial hyperstriatum ventrale is involved in learning paradigms, including imprinting and passive
avoidance learning. Biochemical changes in the intermediate medial hyperstriatum ventrale following learning include an up‐regulation of
amino‐acid transmitter levels and receptor activity. To follow the changes of extracellular amino acid levels during passive avoidance training,
we used an in vivo microdialysis technique. Probes were implanted in chicks before training the animals, either on a methyl‐ anthranylate‐or water‐coated bead. One hour later, recall was tested in both groups by presenting a similar bead. An increase of extra‐cellular glutamate levels accompanied training and testing in both groups; during training, glutamate release was higher in methylanthranylate‐ trained than in water‐trained chicks. When compared with the methylanthranylate‐trained chicks during testing, the water‐trained chicks showed enhanced extra‐cellular glutamate levels. No other amino acid examined showed significant changes. After testing, the chicks were anesthetized and release‐ stimulated with an infusion of 50 mM potassium. Extra‐cellular glutamate and taurine levels were significantly increased in both methylanthranylate‐and water‐trained chicks. The presentation of methylanthranylate as an. olfactory stimulus significantly enhanced glutamate levels, especially in methylanthranylate‐trained chicks. The results suggest that such changes in extra‐cellular
glutamate levels in the intermediate medial hyperstriatum ventrale accompany pecking at either the water‐ or the methylanthranylate‐bead. The taste of the aversant may be responsible for the greater increases found in methylanthranylate‐trained birds.
Activation of Human Auditory Cortex in Retrieval Experiments: An fMRI Study
Authors: Gaschler-Markefski Birgit , Baumgart Frank , Tempelmann Claus , Woldorff Marty G. , Scheich Henning
Published: March 2007

In a previous functional magnetic resonance (fMRI) study, a subdivision of the human auditory cortex into four distinct territories was
achieved. One territory (T1a) exhibited functional specialization in terms of a foreground‐background decomposition task involving matching‐to‐sample monitoring on tone sequences. The present study more specifically determined whether memory‐guided analysis of tone sequences is part of the T1a specialization. During the encoding periods, an arbitrary and unfamiliar four‐tone‐sequence
(melody) played by one instrument was presented. The melody‐instrument‐combination was different in each period. During subsequent
retrieval periods, learned and additional combinations were presented, and the tasks were either to detect the target melodies
(experiment I) or the target instruments (experiment II). T1a showed larger activation during the melody retrieval. The results
generally suggest that (1) activation of T1a during retrieval is determined less by the sound material than by the executed task, and (2) more
specifically, that memory‐guided sequential analysis in T1a is dominant over recognition of characteristic complex sounds.
Ultrastructure of Mauthner Cells in Fish Adapted to Long‐Duration Vestibular Stimulation and the Effect of Ethanol
Authors: Tiras Nadezhda R. , Zherdev Georgy V. , Moshkov Dmitry A.
Published: March 2007

Adaptation or resistance of fish Mauthner cells (M‐cells) to long duration (2 h) vestibular stimulation (LDS)was produced by daily brief
and gradually increasing vestibular stimulation (training). The LDS resistance was accompanied by an increase in the number of desmosome‐like junctions in the afferent axosomatic synapses. F‐actin, the main component of desmosome‐like contacts, has been suggested to be responsible for the increased resistance of M‐cells to LDS. The purpose of the present study was to investigate
the capacity of M‐cells to adapt to LDS under the influence of ethanol, which alters the content of F‐actin in cells. The experiments were carried out in goldfish fry. Vestibular stimulation (training and LDS) was performed in special drums that were rotated in two
planes. The training time was increased from 1 min on day 1 to 30 min on day 30. For ethanol exposure, fish were immersed daily in a 2%
ethanol solution for 20 min. To assess the level of resistance to LDS, motor activity indicating the functional state of M‐cells was evaluated before and after LDS. The results show that exposure to ethanol reduces the resistance to LDS in both untrained and trained fish. Electron microscopic data demonstrated some structural changes in the synaptic endings located on M‐cell soma in ethanol‐exposed fish.
Wrapping of boutons by cytoplasmic out‐ growths and myelin‐ like structures was observed. Morphometric analysis revealed that
exposure to ethanol without training decreases the number of desmosome‐like contacts, probably due to ethanol‐induced depolymerization
of cytoskeletal actin. Ethanol exposure also partly suppressed the increase in the number of desmosome‐like contacts that occurs as a result of training. In ethanol‐treated trained fish, however, a concomitant increase in the length of desmosome‐like contacts was observed. As training alone leads to the formation of additional desmosome‐like contacts of standard length, it is possible that although a sufficient amount of such structures cannot be formed in the M‐cells of ethanol‐exposed trained fish, the existing contacts can be elongated. Thus, possibly changes of the actin state are involved in the adaptation of M‐cells to LDS.
Characteristics of Glial Reaction in the Perinatal Rat Cortex: Effect of Lesion Size in the ‘Critical Period’
Authors: Kálmán Mihály , Ajtai Béla M. , Sommernes Jon Håvard
Published: March 2007

In this study we investigate the capability of
lesions, performed between embryonic day E18
and postnatal day P6, to provoke glial reaction.
Two different lesion types were applied: ‘severe’
lesion (tissue defect) and ’light’ lesion (stab
wound). The glial reaction was detected with
immunostain[ng against glial fibrillary acidic
protein. When performed as early as P0, severe
lesions could result in reactive gliosis, which
persisted even after a month. The glial reaction
was detected at P6/P7 and became strong by P8,
regardless of the age when the animals were
lesioned between P0 and P5. Namely, a strict
limit could be estimated for the age when
reactive glia were already found rather than for
the age when glial reaction‐provoking lesions
could occur. After prenatal lesions, no glial
reaction developed, but the usual glia limitans
covered the deformed brain, surface. Light
lesions provoked glial reactions when
performed at P6. In conclusion, three scenarios
were found, depending on the age of the animal
at injury: (i) healing without glial reaction,
regardless of the remaining deformation; (ii) depending on the size of the lesion, either healing without residuum or with remaining
tissue defect plus reactive gliosis; and (iii) healing always with reactive gliosis. The age limits between them were at P0 and P5. The glial reactivity seemingly appears after the end of the neuronal migration and just precedes the massive transformation of the radial glia into astrocytes. Estimating the position of the appearance of glial reactivity among the events of cortical maturation can help to adapt the experimental results to humans.
Tyrosine Hydroxylase in Vasopressinergic Axons of the Pituitary Posterior Lobe of Rats Under Salt‐Loading as a Manifestation of Neurochemical Plasticity
Authors: Abramova Marina , Calas André , Thibault Jean , Ugrumov Michael
Published: March 2007

In this.study, we attempted to test whether
tyrosine hydroxylase (TH), the first ratelimiting
enzyme of catecholamine synthesis, is
confined to the perikarya of activated magnocellular
vasopressinergic (VPergic) neurons or
is also present in their distal axons in the
pituitary posterior lobe (PL). In addition, we
evaluated the possible correlation between TH
and VP turnover in the axons of rats drinking
2% NaCl for 1, 2, and 3 weeks. To this aim, we
examined the large swellings of VPergic axons,
the so‐called Herring bodies, using the doubleimmunofluorescent
technique and the avidinbiotin
technique, combined with image analysis.
Here we have demonstrated for the first time a
colocalization of TH and VP in Herring bodies,
which is a strong argument in favor of TH
transport from the perikarya of VPergic
neurons via axons toward their terminals. THimmunoreactive
(IR) and VP‐IR materials were distributed in Herring bodies with seeming
zonality. The number of VP‐IR Herring bodies
decreased by a factor of four over the first week
of osmotic stimulation, remaining at almost the
same low level until the end of the experiment.
Conversely, the content of the VP‐IR material
within the individual Herring bodies fell
gradually during the three weeks of saltloading.
The results suggest that VP depletion
from Herring bodies prevails in its transport
into these structures during the whole period of
osmotic stimulation. In contrast to VP‐IR
Herring bodies, the number of TH‐IR Herring
bodies and the content of TH‐IR material
within the individual Herring bodies increased
progressively during the entire experiment. The
synchronization of the VP depletion and TH
accumulation in Herring bodies during longterm
osmotic stimulation raised the question
about a possible functional interaction between
both substances.
GABA and Muscimol as Reversible Inactivation Tools in Learning and Memory
Authors: Majchrzak M. , Di Scala G.
Published: March 2007

Reversible inactivation of brain areas is a useful method for inferring brain‐behavior relationships. Infusion of GABA or of the GABA receptor agonist muscimol is considered one interesting reversible inactivation method because it may not affect fibers of passage and may therefore be compared to axon‐sparing types of lesions. This article reviews the data obtained with this method in learning and memory experiments. A critical analysis of data, collected in collaboration with Simon Brailowsky, with chronic GABA infusion is presented, together with an illustration of data obtained with muscimol‐induced inactivation.
Neonatal 5,7‐DHT Lesions Cause Sex‐Specific Changes in Mouse Cortical Morphogenesis
Authors: Hohmann Christine F. , Richardson Celena , Pitts Ella , Berger-Sweeney Joanne
Published: March 2007

Both monoaminergic and cholinergic afferent
projections to the neocortex putatively modulate
cortical morphogenesis and plasticity. Previously
we showed that neonatal,electrolytic lesions:
the cholinergic nucleus basalis magnocel!ularis
(nBM) projections to the neocortex result in
significant decreases‐of cortical layer width that
correlate with cognitive alterations. Such electrolytic
lesions, performed for lack of a selective
neurotoxin in mice, may affect mono‐ aminergic
fibers of passage. Here, we investigate the effects
of neonatal 5,7 dihydroxytryptamine (5,7‐DHT)
focal injections into the nBM region on cortical
laminar morphology in adult male and female
mice. 5,7‐DHT lesions on the first postnatal day
resulted in significant cortical depletion of both
serotonin and norepinephrine that attenuated
with age. Generally, cortical layer widths
increased in response to the lesion; the effects
were layer, region, and sex specific. Previous
reports from our laboratories described longterm
behavioral alterations after comparable
focal, neonatal 5,7‐DHT lesions. The studies
described here provide an anatomical basis for
such behavioral alterations. Our data suggest
that monoaminergic and cholinergic projections to the cortex may have opposite effects on the
developing cortical neuropil. Jointly, our
morphological and behavioral findings may
have important implications for a variety of
developmental disorders in humans and
provide some insights into sex differences in the
penetrance of these disorders.
Parental Deprivation Induces N‐Methyl‐D‐Aspartate‐Receptor Upregulation in Limbic Brain Areas of Octodon degus: Protective Role of the Maternal Call
Authors: Ziabreva Irina , Schnabel Reinhild , Braun Katharina
Published: March 2007

An optimal coordination between parents
and their offspring involves a sequence of
reciprocal behaviors to ensure the adequate
care of the young, which is critical for a healthy
physical, emotional, and social development.
Parental deprivation, particularly an impaired
child‐mother attachment, induces lasting
changes in emotional as well as in cognitive
capacities in later life. We assessed in the South
American precocial species, Octodon degus,
whether alterations of glutamatergic function
of the limbic system induced by parental
deprivation may be a neural correlate for such
behavioral changes. Further, we analyzed
whether the mother′s voice can protect from
separation‐induced changes of brain function.
Changes of N‐methyl‐D‐aspartate (NMDA)
receptor expression were examined in the
following three groups of 2‐week‐old Octodon degus
pups: (I) control animals who remained
undisturbed with the family; (II) animals who
were repeatedly separated from the family and
individually placed in an unfamiliar environment
for behavioral analysis (open field); and (III)
animals who were treated like the group described under (lI) but were presented with
maternal vocalizations during separation.
Relative to those in the control group I, the
animals in group II showed an upregulation of
NMDA receptor density in the (a)anterior
cingulate, prelimbic, infralimbic, and anterior
insular cortices; (b)CA1/stratum radiatum;
(c)CA1/stratum lacunosum moleculare and
CA3/stratum radiatum; and (d)in the basomedial
amygdaloid nucleus. Presentation of the
maternal call during the separation period
(group III) suppressed the separation‐induced
NMDA receptor upregulation in all regions.
The results demonstrate that early life events
can influence the expression of transmitter
receptors and that maternal behavior, acting to
control the pup′s socio‐emotional environment,
is a key factor for regulating such developmental
events.
Improvement of Impaired Memory in Mice by Taurine
Authors: Vohra Bhupinder P. S. , Hui Xiang
Published: March 2007

Taurine was extracted from Pegasus later-narius Cuvier
to study its effects on learning and
memory in mice. Mice were treated with different
doses of taurine (10 mg/kg, 20 mg/kg, 40 mg/kg).
The mice were treated with various chemical
agents (pentobarbital, cycloheximide, sodium
nitrite, alcohol) to disrupt the normal memory
process. We measured the effect of taurine on
step‐down latency (SDL) and escape latency (EL)
in a passive avoidance task after 10 or 30 days.
Treatment with taurine alone did not change
either SDL or EL. Taurine protected mice .from
the memory disruption induced by alcohol,
pentobarbital, sodium nitrite, and cycloheximide
but had no obvious effect on motor coordination,
exploratory activity, or locomotor activity as
measured using the rota‐rod test and the hole
board test. We conclude that taurine can be
effective in attenuating the amnesia produced
by alcohol, pentobarbital, cycloheximide, and
sodium nitrite without compromising the
behavioral aspects of the animals tested.
Enhanced Behavioral Recovery from Sensorimotor Cortex Lesions After Pyramidotomy in Adult Rats
Authors: Fanardjian V. V. , Gevorkyan O. V. , Mallina R. K. , Melik-Moussian A. B. , Meliksetyan I. B.
Published: March 2007

Unilateral transection of the bulbar
pyramid, performed before the ablation of the
ipsilateral sensorimotor cortex, has been shown
to facilitate the recovery of operantly conditioned
reflexes and compensatory processes in rats.
Such enhanced behaviorai recovery was absent
when only the sensorimotor cortex was ablated.
This phenomenon is explained by the switching
of motor activity under the control of the
cortico‐rubrospinal system. Switching of the
descending influences is accomplished through
the following loop: cortico‐rubrai projectionred
nucleus‐inferior olive‐cerebellum‐thalamuscerebral
cortex. This suggests that a preliminary
lesion of the peripheral part of the
system, represented by a descending spinal
projection, facilitates the recovery processes to
develop during the subsequent destruction of its
central part.
CREB Phosphorylation Coincides with Transient Synapse Formation in the Rat Hippocampal Dentate Gyrus Following Avoidance Learning
Authors: O′Connell Cormac , Gallagher Helen C. , O′Malley Aoibheinn , Bourke Mary , Regan Ciaran M.
Published: March 2007

Spine density change in the hippocampal
dentate gyrus accompanies memory consolidation
and coincides with the increased expression of
ribosome‐rich, hyperchromatic granule cells.
Although this suggests increased protein synthesis
to be required for synaptic growth in the 5 to 7 h
post‐training period, little temporal mapping of
the associated molecular mechanisms has been
done. Here, we demonstrate a similar frequency
of hyperchromatic cells in naïve animals and in
those sacrificed 6 h post‐training, suggesting a
transient repression of protein synthesis in the
early post‐training period. Immunoblot analysis
of CREB phosphorylation in the dentate gyrus
supported this view, with downregulation from
basal levels observed at 2 to 3 h and at 12 h posttraining.
Protein synthesis reactivation appears to
be specific for de novo spine production as no
change in spine frequency accompanies the
immediate post‐training period of depressed
protein synthesis. These findings support the view
that CREB‐mediated gene transcription is a
requirement for long‐term memory consolidation
and may be directly implicated in the process of
synaptic growth.
ACTH4 ‐10, Substance P, and Dizolcipine (Mk‐801) Accelerate Functional Recovery After Hemilabyrinthectomy in Goldfish
Authors: Mattioli R. , Huston J. P. , Spieler R. E.
Published: March 2007

In this study, we evaluated the goldfish model
of hemilabyrinthectomy for investigating potential
recovery‐promoting drugs. In this lesion model,
the unilateral removal of the labyrinth induces a
postural imbalance in response to light (Dorsal
Light Reflex), from which the animals can
recover over time. The behavioral effects of two
neuropeptides were tested–namely, of substance
P and ACTH4‐10, both of which are known to
promote functional recovery in several other
lesion models. Furthermore, the effect of MK‐
801, an antagonist of the glutamatergic NMDAreceptor
subtype, was tested because this
substance has also been shown to exert a
neuroprotective effect. After lesion of the right
labyrinth, the animals (n=12)
were treated intraperitoneally
daily either with vehicle (n=12),
substance P (n=11)
, ACTH4‐10 (n=12)
, or MK‐
801 (n=12)
. Another group (n=11)
, which served
as a non‐lesion control, did not receive hemilabyrinthectomy
or systemic injections. The
lesion group, treated post‐operatively with vehicle,
did not recover from the postural deviation over
the 24‐d testing period. In contrast, all three test
substances accelerated the functional recovery
after unilateral labyrinthectomy. The decrease of
the dorsal light reflex persisted even after
cessation of drug treatment after 20d. The
results indicate that using the dorsal light reflex
in the model of hemilabyrinthectomy in goldfish
provides a useful approach to studying the
ability of potential new neurotrophic or neuroprotective
drugs to promote functional recovery.
Functional and Anatomic Correlates of Two Frequently Observed Temporal Lobe Seizure‐Onset Patterns
Authors: Velascol Ana Luisa , Wilson Charles L. , Babb Thomas L. , Engel Jr Jerome
Published: March 2007

Intracranial depth electrode EEG records
of 478 seizures, recorded in 68 patients
undergoing diagnostic monitoring with depth
electrodes, were evaluated to investigate the
correlates of electrographic onset patterns in
patients with temporal lobe seizures. The
seizure onsets in 78% of these patients were
identified as either hypersynchronous onsets,
beginning with low‐frequency, high‐amplitude
spikes, or low‐voltage fast (LVF) onsets,
increasing in amplitude as the seizure
progressed. The number of patients (35)
having hypersynchronous seizure onsets was
nearly twice that of patients (18) having LVF
onsets. Three major differences were seen
among patients with the two seizure‐onset
patterns. When compared with patients
having LVF onsets, patients with hypersynchronous
seizure onsets had a significantly
greater probability of having (1) focal rather
than regional seizure onsets (p<0.01), (2) seizures
spreading more slowly to the contralateral
mesial temporal lobe (p<0.003), and (3) cell
counts in resected hippocampal tissue showing
greater neuronal loss (p<0.001). The results
provide evidence that the most frequent electrographic abnormality associated with
mesial temporal seizures is local hypersynchrony,
a condition associated with major
neuronal‐loss in the hippocampus. The results
also indicate that LVF seizure onsets more
frequently represent widely distributed discharges,
which interact with and spread more
rapidly to surrounding neocortical areas.
Parallel Information Processing in Motor Systems: Intracerebral Recordings of Readiness Potential and CNV in Human Subjects
Authors: Rektor Ivan
Published: March 2007

We performed intracerebral recordings of
Readiness Potential (RP) and Contingent Negative
Variation (CNV) with simple repetitive distal limb
movement in candidates for epilepsy surgery. In 26
patients (in Paris), depth electrodes were located in
various cortical structures; in eight patients (in
Brno), in the basal ganglia and the cortex. RPs
were displayed in the conteral primary motor
cortex, conteral somato‐sensory cortex, and
bilaterally in the SMA and the caudal part of the
anterior cingulate cortices. CNVs were recorded in
the same cortical regiom as the RP, as well as in
the ipsilateral primary motor cortex, and
bilaterally in the premotor fronto‐lateral, parietal
superior, and middle temporal regions. In the basal
ganglia, the RP was recorded in the putamen in six
of seven patients, and in the head of the caudate
nucleus and the pallidum in the only patient with
electrodes in these recording sites. We suggest that
our results are consistent with a long‐lasting,
simultaneous activation of cortical and subcortical
structures, before and during self‐paced and
stimulus‐triggered movements. The particular
regiom that are simultaneously active may be
determined by the task context.
The Motor System: The Whole and its Parts
Authors: Otten E.
Published: March 2007

Our knowledge of components of the human
motor system has been growing steadily, but our
understanding of its integration into a system is
lagging behind. It is suggested that a combination
of measurements of forces and movements of the
motor system in a functionally meaningful
environment in conjunction with computer
simulations of the motor system may help us in
understanding motor system properties. Neurotrauma
can be seen as a natural deviation, with
recovery as a slow path to yet another deviant
state of the motor system. In that form they may
be useful in explaining the close interaction
between form and function of the human motor
system.
Exercise and Training to Optimize Functional MotorPerformance in Stroke: Driving Neural Reorganization?
Authors: Shepherd Roberta B.
Published: March 2007

Neurorehabilitation is increasingly taking account of scientific findings. Research areas directing stroke rehabilitation are neurophysiology; adaptability to use and activity; biomechanics; skill learning; and exercise science (task, context specificity). Understanding impairments and adaptations enables a reappraisal of interventions—for example,changes in motor control resulting from impairments (decreased descending inputs, reduced motor unit synchronization), secondary soft tissue changes (muscle length and stiffness changes) are adaptations to lesion and disuse. Changes in interventions include increasing emphasis on active exercise and task‐specific training, active and passive methods of preserving muscle extensibility. Training has the potential to drive brain reorganization and to optimize functional performance. Research drives the development of training programs, and therapists are relying less on one‐to‐one, hands‐on service delivery, making use of circuit training and group exercise and of technological advances (interactive computerized systems, treadmills) which increase time spent in active practice, Emphasis is on skill training, stressing cognitive engagement and practice, aiming to
increase strength, control, skill, endurance, fitness, and social readjustment. Rehabilitation services remain slow to make the changes necessary to upgrade environments, attitudes, and rehabilitation methodologies to those shown to be more scientifically rational and for which there is evidence of effectiveness.
Normal and Abnormal Development of Motor Behavior:Lessons From Experiments in Rats
Authors: Gramsbergen Albert
Published: March 2007

In this essay a few relevant aspects of the neural and behavioral development of the brain in the human and in the rat are reviewed and related to the consequences of lesions in the central and peripheral nervous system at early and later age. Movements initially are generated by local circuits in the spinal cord and without the involvement of descending projections. After birth, both in humans and in rats it seems that the devlopment of postural control is the limiting factor for several motor behaviors to mature. Strong indications exist that the cerebellum is significantly involved in this control. Lesions in the CNS at early stages interfere with fundamental processes of neural development, such as the establishment of fiber connections and cell death patterns. Consequently, the functional effects are strongly dependent on the stage of development. The young and undisturbed CNS, on the other hand, has a much greater capacity than the adult nervous system for compensating abnormal reinnervation in the peripheral nervous system. Animal experiments indicated that the cerebellar cortex might play an important part in this compensation. This possibility should be investigated further as it might offer important perspectives for treatment in the human.
Physiological and Morphological Characterization ofOrganotypic Cocultures of the Chick Forebrain AreaMNH and its Main Input Area DMA/DMP
Authors: Endepols Heike , Jungnickel Julia , Braun Katharina
Published: March 2007

Cocultures of the learning‐relevant forebrain
region mediorostrai neostriatum and
hyperstriatum ventrale (MNH) and its main
glutamatergic input area nucleus dorsomedialis
anterior thalami/posterior thalami were morphologically
and physiologically characterized.
Synaptic contacts of thalamic fibers were lightand
electron‐microscopically detected on MNH
neurons by applying the fluorescence tracer
DiI‐C18(3) into the thalamus part of the coculture.
Most thalamic synapses on MNH neurons
were symmetric and located on dendritic shafts,
but no correlation between Gray‐type ultrastructure
and dendritic localization was found.
Using intraceilular current clamp recordings, we
found that the electrophysiological properties,
such as input resistance, time constant, action
potential threshold, amplitude, and duration of
MNH neurons, remain stable for over 30 days in
vitro. Pharmacological blockade experiments
revealed glutamate as the main neurotransmitter
of thalamic synapses on MNH neurons, which
were also found on inhibitory neurons. High
frequency stimulation of thalamic inputs evoked
synaptic potentiation in 22%
of MNH neurons.
The results indicate that DMA/DMP‐MNH cocultures,
which can be maintained under stable
conditions for at least 4 weeks, provide an
attractive in vitro model for investigating
synaptic plasticity in the avian brain.
Task‐ and Time‐Dependent Memory Enhancement byDehydroepiandosterone in Day‐Old Chicks
Authors: Johnston A. N. B. , Migues P. V.
Published: March 2007

We have previously reported the presence
of dehydroepiandosterone (DHEA) in the dayold‐
chick brain, and a role for it in enhanced
memory formation. Here we confirm that
intracerebral injections of DHEA 5 min before
training on the weak passive avoidance task
enhanced recall 24 hours after training. Recall
per se on an appetitive visual categorization
task was not altered by administration of
DHEA 5 min before training. However
administration of DHEA 5 min before limited
or very limited training on a visual categorization
task (20 or 10 pecks only) appeared to
enhance consolidation of this task at test 24 h
after training; reducing the latency and total
time taken to complete the test (60 pecks), while
not detrimentally altering accuracy. Moreover,
DHEA is unlikely to induce this effect via
possible anxiolytic effects because it did not
alter behavior in the open field test. We also
examined diffusion of DHEA throughout the
brain at various stages following intracerebral
injection.
Tyrosine Hydroxylase Expression in Differentiating Neurons of theRat Arcuate Nucleus: Stimulatory Influence of Serotonin Afferents
Authors: Melnikova Viktoria I. , Ugrumov Michael V. , Proshlyakova Evgenia V. , Calas André , Thibault Jean
Published: March 2007

The influence of serotonin afferents on
tyrosine hydroxylase expression in differentiating
neurons of the rat arcuate nucleus was studied
in vivo and in vitro. In the in vivo study, pchlorophenylalanine
inhibited serotonin synthesis
in fetal brain from the 11th
to the 20th
embryonic
day. We then used semiquantitative immunocytochemistry
to evaluate tyrosine hydroxylase
levels in neurons of the arcuate nucleus in
fetuses at the 21st
embryonic day or in offspring
at the 35th
postnatal day. Serotonin depltion
significantly decreased the tyrosine hydroxylase
content in neurons of males and females at the
21st
embryonic day and in males at the 35th

postnatal day. For the in vitro study, embryonic
neurons of the arcuate nucleus were cocultured
with embryonic neurons of the raphe
nucleus, the main source of serotonin innervation
of the brain, including the arcuate nucleus.
Co‐culture of the neurons resulted in a genderspecific
increase of the tyrosine hydroxylase
level in the neurons of the arcuate nucleus. In
turn, the neurons of the raphe nucleus showed
increased levels .of serotonin in both males and
females, with no sexual dimorphism. Thus, our
results suggest a stimulatory, long‐lasting effect
of serotonin afferents on tyrosine hydroxylase
expression in the differentiating neurons of the
rat arcuate nucleus during prenatal ontogenesis.
Alterations of Amino Acids and Monoamine Metabolism inMale Fmr1 Knockout Mice: A Putative Animal Model ofthe Human Fragile X Mental Retardation Syndrome
Authors: Gruss Michael , Braun Katharina
Published: March 2007

The Fragile X syndrome, a common form of
mental retardation in humans, is caused by
silencing the fragile X mental retardation (FMR1)
geneleading to the absence of the encoded fragile
X mental retardation protein 1 (FMRP). We
describe morphological and behavioral abnormalities
for both affected humans and Fmr1
knockout mice, a putative animal model for the
human Fragile X syndrome. The aim of the
present study was to identify possible neurochemical
abnormalities in Fmr1 knockout mice,
with particular focus on neurotransmission.
Significant region‐specific differences: of basal
neurotransmitter and metabolite levels were
found between wildtype and Fmr1 knockout
animals, predominantly in juveniles (post‐natal
days 28 to 31). Adults (postnatal days 209 to
221) showed only few abnormalities as compared
with the wildtype. In juvenile knockout mice,
aspartate and taurine were especially increased
in cortical regions, striatum, hippocampus, cerebellum,
and brainstem. In addition, juveniles
showed an altered balance between excitatory and
inhibitory amino acids in the caudal cortex,
hippocampus, and brainstem. We detected very
few differences in monoamine turnover in both
age stages. The results presented here provide
the first evidence that lack of FMRP expression
in FMRP knockout mice is accompanied by
age‐dependent, region‐specific alterations in
neurotransmission.
Early Brain Damage and the Development of Motor Behaviorin Children: Clues for Therapeutic Intervention?
Authors: Hadders-Algra Mijna
Published: March 2007

The Neuronal Group Selection Theory (NGST) could offer new insights into the mechanisms directing motor disorders, such as cerebral palsy and developmental coordination disorder. According to NGST, normal motor development is characterized by two phases of variability. Variation is not at random but determined by criteria set by genetic information. Development starts with the phase of primary variability,during which variation in motor behavior is not geared to external conditions. At function‐specific ages secondary variability starts, during which motor performance can be adapted to specific situations. In both forms, of variability, selection on the basis of afferent information plays a significant role. From the NGST point of view, children with pre‐ or perinatally acquired brain damage, such as children with cerebral palsy and part of the children with developmental coordination disorder, suffer from stereotyped motor behavior, produced by a limited repertoire or primary (sub)cortical neuronal networks. These children also have roblems in selecting the most efficient neuronal activity, due to deficits in the processing of sensory information. Therefore, NGST suggests that intervention in these children at early age should aim at an enlargement of the primary neuronal networks. With increasing age, the emphasis of intervention could shift to the provision of ample opportunities for active practice, which might form a compensation for the impaired selection.
Parkinson′s Disease: Clinical Signs and Symptoms,Neural Mechanisms, Positron Emission Tomography,and Therapeutic Interventions
Authors: Leenders K. L. , Oertel W. H.
Published: March 2007

Parkinson′s disease is one of the most
frequent neurodegenerative brain diseases. Its
time course is slow and is characterized by
progressive loss of dopaminergic and other
brainstem neurons resulting in malfunctioning of
the cerebral neuronal systems responsible for
motor functions. The clinical signs are slowness
of movement, muscle rigidity and rest‐tremor
amongst other features. The cause of the disease
is unknown, but recently involvement of genetic
factors is being researched. Positron emission
tomography (PET) allows in vivo determination
of striatai dopaminergic activity. This has
increased our insight in the pathophysiology of
the disease and permits direct study of disease
progression at a biochemical level and equally to
monitor whether potential neuroprotective interventions
are indeed effective. Thus far no drug
has emerged but promising substances are
currently being studied.
Vision After Early-Onset Lesions of the Occipital Cortex:I. Neuropsychological and Psychophysical Studies
Authors: Kiper D. C. , Zesiger P. , Maeder P. , Deonna T. , Innocenti G. M.
Published: March 2007

We analyzed the visual functions of two
patients (MS, FJ) with bilateral lesion of the
primary visual cortex, which occurred at gestational
age 33 wk in MS and at postnatal month 7
in FJ. In both patients basic visual functions—
visual acuity, contrast sensitivity, color, form,
motion perception—are similarly preserved or
modestly impaired. Functions requiring higher
visual processing, particularly figure‐ground
segregation based on textural cues, are severely
impaired. In MS, studied longitudinally, the
deficits attenuated between the ages of 4.5 and 8
y, suggesting that the developing visual system
can display a considerable degree of adaptive
plasticity several years after the occurrence of a
lesion. In FJ (age 18:9 to 20:6 y), who is more
impaired, the recovery, if any, was less.
Transcortical Alterations in Na+‐K+ ATPase and Microtubule‐Associated Proteins Immunoreactivity in the Rat Cortical Atrophy Model Induced by Hypoxic Ischemia
Authors: Suh Jun-Gyo , An Sung-Jin , Park Jae-Bong , Ryoo Zae-Young , Lee Jeong Woong , Oh Yang-Seok , Won Moo Ho , Kang Tae-Cheon
Published: March 2007

To identify the chronological transcortical
change in the contralateral hemisphere
following ischemic insults, we investigated the
changes in microtubule associated protein
(MAP) and Na+‐K+ ATPase expressions in the
peri‐infarct zone and contralateral hemisphere,
including the hippocampus. Two days after
hypoxic ischemia, Na+‐K+ ATPase immunoreactivity
was significantly enhanced in the
contralateral cortex and was maintained up to 7
days after ischemia, whereas Na+‐K+ ATPase immunoreactivity in the peri‐ and infarct zones
was unaffected by hypoxic ischemia. In contrast,
2 to 7 days after ischemia, MAP1A and MAP2
immunoreactivity in the ipsi‐ and contralateral
cortex significantly decreased, whereas in layer
V, MAP1 immunoreactivity obviously accumulated
in the neurons and their processes. In the
hippocampus, 2 days after insults both MAP1A
and MAP2 immunoreactivity was significantly
reduced within the ipsi‐ and contralateral
hippocampus. In the contralateral hippocampus,
however, the distribution of MAP2 immunoreactivity
recovered to the sham level 7 days
after ischemia, whereas MAP1A immunoreactive
axons remained 2 months after
ischemia. The results suggest that the unilateral
elevation of Na+‐K+ ATPase immunoreactivity
reflects elevated neuronal activity. In addition,
this asymmetric hyperexcitability might play an
important role in the recovery or the
reorganization of the brain, accompanied by
transcortical changes in MAPs expression.
Different Modes of Pitch Perception and Learning‐InducedNeuronal Plasticity of the Human Auditory Cortex
Authors: Schulte Michael , Knief Arne , Seither-Preisler Annemarie , Pantev Christo
Published: March 2007

We designed a melody perception experiment
involving eight harmonic complex tones of
missing fundamental frequencies (hidden auditory
object) to study the short‐term neuronal plasticity
of the auditory cortex. In this experiment, the
fundamental frequencies of the complex tones
followed the beginning of the virtual melody of
the tune “Frère Jacques”. The harmonics of the
complex tones were chosen so that the spectral
melody had an inverse contour when compared
with the virtual one. Evoked magnetic fields were
recorded contralaterally to the ear of stimulation
from both hemispheres. After a base line measurement,
the subjects were exposed repeatedly to the
experimental stimuli for 1 hour a day. All subjects
reported a sudden change in the perceived melody,
indicating possible reorganization of the cortical
processes involved in the virtual pitch formation.
After this switch in perception, a second measurement
was performed. Cortical sources of the
evoked gamma‐band activity were significantly
stronger and located more medially after a switch
in perception. Independent Component Analysis
revealed enhanced synchronization in the gamma‐band
frequency range. Comparing the gamma‐band
activation of both hemispheres, no
laterality effects were observed. The results
indicate that the primary auditory cortices are
involved in the process of virtual pitch
perception and that their function is modifiable
by laboratory manipulation.
Correlation of Clinical Neuromusculoskeletal and CentralSomatosensory Performance: Variability in Controls and PatientsWith Severe and Mild Focal Hand Dystonia
Authors: Byl Nancy N. , Nagarajan Srikantan S. , Merzenich Michael M. , Roberts Tim , McKenzie Alison
Published: March 2007

Focal hand dystonia (FHd) is a recalcitrant,
disabling movement disorder, characterized by
involuntary co‐contractions of agonists and
antagonists, that can develop in patients who
overuse or misuse their hands. The aim of this
study was to document clinical neuromusculoskeletal
performance and somatosensory
responses (magnetoencephalography) in healthy
controls and in FHd subjects with mild versus
severe hand dystonia. The performance of
healthy subjects (n = 17) was significantly better
than that of FHd subjects (n = 17) on all clinical
parameters. Those with mild dystonia (n = 10)
demonstrated better musculoskeletal skills,
task‐specific motor performance, and sensory
discrimination, but the performance of sensory
and fine motor tasks was slower than that of
patients with severe dystonia. In terms of
somatosensory evoked field responses (SEFs),
FHd subjects demonstrated a significant
difference in the location of the hand
representation on the x and y axes, lower
amplitude of SEFs integrated across latency,
and a higher ratio of mean SEF amplitude to
latency than the controls. Bilaterally,. those with
FHd (mild and severe) lacked progressive
sequencing of the digits from inferior to
superior. On the affected digits, subjects with
severe dystonia had a significantly higher ratio
of SEF amplitude to latency and a significantly
smaller mean volume of the cortical hand
representation than those with mild dystonia.
Severity of dystonia positively correlated with
the ratio of SEF mean amplitude to latency
(0.9029 affected, 0.8477 unaffected; p<0.01).
The results of the present study strengthen the
evidence that patients with FHd demonstrate
signs of somatosensory degradation of the hand
that correlates with clinical sensorimotor
dysfunction, with characteristics of the dedifferentiation
varying by the severity of hand
dystonia. If these findings represent aberrant
learning, then effective rehabilitation must
incorporate the principles of neuroplasticity.
Training must be individualized to each patient
to rebalance the sensorimotor feedback loop
and to restore normal fine motor control.
Aging and Synaptic Plasticity: A Review
Authors: Bergado Jorge A. , Almaguer William
Published: March 2007

Aging affects all systems, but the brain seems
to be particularly vulnerable to the action of
negative, age‐dependent factors. A gradual loss
of memory functions is one of the earliest and
most widespread consequences of brain aging.
The causes for such impairment are still unclear.
Long‐term potentiation (LTP) is one form of
neural plasticity, which has been proposed as the
cellular correlate for memory. LTP is affected by
aging, and such alteration might be causally
related to memory dysfunction. In the present
paper, we review the evidence sustaining the
existence of a causal link between cognitive and
LTP impairments, as well as the possible
mechanisms involved. New results indicate a
possible involvement of a deficient reinforcement
of LTP by affective influences.