Estradiol-mediated modulation of memory and of the underlying dendritic spine plasticity through the life span.

The morphophysiology of the nervous system changes and adapts in response to external environmental inputs and the experiences of individuals throughout their lives. Other changes in the organisms internal environment can also contribute to nervous system restructuring in the form of plastic changes that underlie its capacity to adapt to emerging psychophysiological conditions. These adaptive processes lead to subtle modifications of the organisms internal homeostasis which is closely related with the activity of chemical messengers, such as neurotransmitters and hormones.

Modifications to cytoskeleton-associated proteins in dendritic spines underlie the adaptive plasticity involved in long term reference memory.

Spatial learning and memory enables individuals to orientate themselves in an external environment. Synaptic stimulation of dendritic spines on hippocampal place cells underlies adaptive cognitive performance, inducing plastic changes such as spinogenesis, pruning and structural interconversion. Such plastic changes are driven by complex molecular machinery that relies on several actin cytoskeleton-associated proteins (ACAP's), these interacting with actin filaments in the postsynaptic density to guide the conformational changes to spines in accordance with the synaptic information they receive.

Atomoxetine prevents working memory loss in hyperactive rats, mediating plastic changes in prefrontal cortex pyramidal neurons.

Attention Deficit Hyperactivity Disorder (ADHD) causes impaired visuospatial working memory (VWM), which primarily maps to the prefrontal cortex. However, little is known about the synaptic processes underlying cognitive loss in ADHD, or those ultimately involved in the preventive effect observed through the clinical use of Atomoxetine (ATX). To investigate the plasticity underlying ADHD related cognitive loss, and that potentially involved in the preventive action of Atomoxetine, allocentric VWM was assessed, as well as the dendritic spine number and proportional density on pyramidal neurons in the prefrontal cerebral cortex layer III of neonatal 6-hydroxydopamine-lesioned rats.

Spinogenesis and Plastic Changes in the Dendritic Spines of Spinal Cord Motoneurons After Traumatic Injury in Rats.

Background: Spinal cord injury (SCI) is highly incapacitating, and the neurobiological factors involved in an eventual functional recovery remain uncertain. Plastic changes to dendritic spines are closely related with the functional modifications of behavior.

Aim Of The Study: To explore the plastic response of dendritic spines in motoneurons after SCI.

Different patterns of motor activity induce differential plastic changes in pyramidal neurons in the motor cortex of rats: A Golgi study.

Rehabilitation is a process which favors recovery after brain damage involving motor systems, and neural plasticity is the only real resource the brain has for inducing neurobiological events in order to bring about re-adaptation. Rats were placed on a treadmill and made to walk, in different groups, at different velocities and with varying degrees of inclination. Plastic changes in the spines of the apical and basal dendrites of fifth-layer pyramidal neurons in the motor cortices of the rats were detected after study with the Golgi method.

Plastic changes to dendritic spines on layer V pyramidal neurons are involved in the rectifying role of the prefrontal cortex during the fast period of motor learning.

The prefrontal cortex participates in the rectification of information related to motor activity that favors motor learning. Dendritic spine plasticity is involved in the modifications of motor patterns that underlie both motor activity and motor learning. To study this association in more detail, adult male rats were trained over six days in an acrobatic motor learning paradigm and they were subjected to a behavioral evaluation on each day of training.

The motor learning induces plastic changes in dendritic spines of Purkinje cells from the neocerebellar cortex of the rat.

Purpose: The presynaptic stimulatory activity of parallel fibers on the dendritic spines of cerebellar Purkinje cells (PC) has a strong influence on the organization of motor learning. Motor learning has been shown to modify the synapses established on PC dendritic spines but the plastic changes of the different spine types, possibly underlying motor learning, have not been studied.

Methods: Adult male Sprague-Dawley rats were trained daily for 26 days using an acrobatic paradigm (AC), at the end of which dendritic spine density and the proportion of the different types of spines was assessed.

Plastic changes in dendritic spines of hippocampal CA1 pyramidal neurons from ovariectomized rats after estradiol treatment.

Cognitive impairment or its recovery has been associated with the absence or reestablishment of estrogenic actions in the central nervous system of female experimental animals or women. It has been proposed that these cognitive phenomena are related to estrogen-mediated modulatory activity of synaptic transmission in brain structures involved in cognitive functions. In the present work a morphological study was conducted in adult female ovariectomized rats to evaluate estradiol-dependent dendritic spine sprouting in hippocampal pyramidal neurons, and changes in the presynaptic marker synaptophysin.

Prefrontal serotonin depletion impairs egocentric, but not allocentric working memory in rats.

Working memory is a cognitive ability chiefly organized by the prefrontal cortex. Working memory tests may be resolved based on allocentric or egocentric spatial strategies. Serotonergic neurotransmission is closely involved in working memory, but its role in spatial strategies for working memory performance is unknown.

Guided motor training induces dendritic spine plastic changes in adult rat cerebellar purkinje cells.

The simple cerebellar lobule is involved in several neuromotor processes and it is activated during guided exercise. Although guided exercises are essential for motor rehabilitation, the plastic events that occur in the simple cerebellar lobule during motor training remain unknown. In this study, normal adult rats were intensely trained on a motorized treadmill during a period of four weeks (IT group) varying both the velocity and the slope of the moving belt, and they were compared to a mildly trained (MC) group and an intact control group (IC).