Neuronal Plasticity

Physical activity (PA) is emerging as a safe and effective tool in the prevention and treatment of psychiatric disorders. PA subtypes include aerobic, resistance, flexibility, neuromotor (involving balance, agility and co-ordination), mind-body (e.g. tai chi, qi gong and yoga) and mixed type trainings. Evidence from clinical trials suggests that PA subtypes can have positive clinical effects, however the effects on the symptomatology may vary according to the PA subtype.

Physical activity (PA) is emerging as a safe and effective tool in the prevention and treatment of psychiatric disorders. PA subtypes include aerobic, resistance, flexibility, neuromotor (involving balance, agility and co-ordination), mind-body (e.g. tai chi, qi gong and yoga) and mixed type trainings. Evidence from clinical trials suggests that PA subtypes can have positive clinical effects, however the effects on the symptomatology may vary according to the PA subtype.

Cognitive plasticity, a developmental trait that promotes acquisition of complex skills such as language or playing musical instruments, diminishes substantially during puberty. The loss of plasticity has been attributed to surge of sex steroids during adolescence, but the phenomenon remains poorly understood. We hypothesize that pineal involution during puberty may contribute to plasticity decay. The pineal gland produces melatonin, the level of which declines dramatically during onset of puberty.

Insulin and insulin-like signaling regulate survival and lifespan in a variety of animal species, from nematodes and flies to higher vertebrates and mammals. Recently, it was shown that brain IGF-I receptor and brain IRS2 control mammalian lifespan, and that this occurs through neuroendocrine mechanisms, control of energy metabolism and modified stress resistance. Furthermore, it was demonstrated that insulin receptor substrate molecules are implicated downstream of insulin and IGF receptors in the extension of lifespan.

The author focused on the functional decline of synapses in the brain with aging to understand the underlying mechanisms and to ameliorate the deficits. The first attempt was to unravel the neuronal functions of gangliosides so that gangliosides could be used for enhancing synaptic activity. The second attempt was to elicit the neuronal plasticity in aged animals through enriched environmental stimulation and nutritional intervention. Environmental stimuli were revealed neurochemically and morphologically to develop synapses leading to enhanced cognitive function.

The introduction of high-resolution time lapse imaging and molecular biological tools has changed dramatically the rate of progress towards the understanding of the complex structure-function relations in synapses of central spiny neurons. Standing issues, including the sequence of molecular and structural processes leading to formation, morphological change, and longevity of dendritic spines, as well as the functions of dendritic spines in neurological/psychiatric diseases are being addressed in a growing number of recent studies.

The author focused on the functional decline of synapses in the brain with aging to understand the underlying mechanisms and to ameliorate the deficits. The first attempt was to unravel the neuronal functions of gangliosides so that gangliosides could be used for enhancing synaptic activity. The second attempt was to elicit the neuronal plasticity in aged animals through enriched environmental stimulation and nutritional intervention. Environmental stimuli were revealed neurochemically and morphologically to develop synapses leading to enhanced cognitive function.

Several lines of evidence support the role of an epigenetic-induced GABAergic cortical dysfunction in schizophrenia psychopathology, which is probably dependent on an increase in the expression of DNA-methyltransferase-1 occurring selectively in GABAergic neurons. The key enzyme regulating GABA synthesis, termed glutamic acid decarboxylase 67 (GAD67) and the important neurodevelopmental protein called reelin are coexpressed in GABAergic neurons. Upon release, GABA and reelin bind to postsynaptic receptors located in dendrites, somata, or the axon initial segment of pyramidal neurons.

Adaptation is a central organizing principle throughout biology, whether we are studying species, populations, or individuals. Adaptation in biological systems occurs in response to molar and molecular environments. Thus, we would predict that genetic systems and nervous systems would be dynamic (cybernetic) in contrast to previous conceptualizations with genes and brains fixed in form and function. Questions of nature versus nurture are meaningless, and we must turn to epigenetics--the way in which biology and experience work together to enhance adaptation throughout thick and thin.

For some neurobiologists, present biological descriptions of the brain may integrate the theoretical frame initiated by Freud. The recent acquisitions of neurobiology prove a plasticity of the neural network anabling the inscription of the experiment. The neuroplasticity constitutes the cornerstone of the reconciliation between the psychoanalysis and neurosciences. The brain must not be considered as a rigid organ, determined and determining but well as a dynamic structure, in constant rebuilding. Contrary to the genetic determinism, the plasticity involves diversity and singularity.