Straightforward reductionistic stances, however, are unfounded because there is clear evidence that our subjective experiences affect the brain.
Multimedia Abstract The number of individuals older than 65 years is projected to exceed While this dramatic increase in the number of individuals at risk for Alzheimer and vascular disease will pose a significant challenge to the health care industry, many older individuals will not actually die of these age-related dementias.
Instead, a significant proportion of those older than 65 years will have to cope with alterations in memory function that are associated with normative aging. A clear understanding of the Neurobiological changes resulting from psychotherapy mechanisms underlying normal age-related changes will be essential in helping elderly populations maintain cognitive performance with increasing age.
This review covers the major age-related alterations in the hippocampus, a critical structure for learning and memory. It has been known for some time that many individuals will exhibit deficits in memory that are unrelated to neuropathologies.
This subtle age-associated decline in normal memory function is not as drastic as the devastating effects of Alzheimer disease, but is nevertheless unsettling. Biological studies of the human nervous system are difficult for many reasons, including ethical issues of invasive studies in living persons and the nearly impossible task of controlling for all genetic and environmental variables among individuals.
To investigate normal age-related impairments at the neuronal or synaptic level with the greatest range of experimental techniques, animal models must be used.
However, animal studies have the limitation that animals cannot describe their experiences directly, making the investigation of certain cognitive functions, such as episodic memory, difficult.
To make inferences about the aging process from the animal model back to the human, rigorous behavioral paradigms must be used to ensure that the same function is being examined across species. Fortunately, the domain of spatial memory provides a common ground between species and happens to be a domain where age-related deficits are described consistently for humans, nonhuman primates, and species such as dogs, rats, and mice.
Because of its critical role in memory in general, and specifically in spatial memory, the hippocampus has been the focus of a productive line of research into the mechanisms of normative aging. Neurobiological changes resulting from psychotherapy hippocampus and spatial memory The importance of the hippocampus in spatial memory was known decades before the discovery of place cells, hippocampal neurons that fire in a location-specific manner.
This finding has been confirmed in targeted lesion studies in a variety of species from rodents to nonhuman primates. In rats, the Morris water maze is frequently used as a test of spatial memory.
In this test, a rat learns the location of a hidden platform below the surface of a tank of opaque water. This platform is always in the same place relative to the tank and the external cues of the testing room.
Aged rats demonstrate impairments in learning this task despite good performance when the platform is visible, 2 indicating that the impairment is attributable to a deficit in spatial memory, as opposed to deficits in visual perception or motivation to leave the water.
Aged rats are also impaired on another test of spatial memory, the Barnes circular platform task. One of the holes leads to a dark tunnel and is rewarding for the rat, as it allows the animal to escape the brightly lit platform. External cues hang on the walls and provide landmarks for the rat to use in learning the relative location of the reward hole.
Aged rats have deficits in learning the position of the escape tunnel, taking significantly longer to reach asymptotic performance on the task. In a study of senescent mice, the same spatial memory deficits were observed as in rats; however, aged animals could perform equivalently to younger animals when the location of the escape tunnel was cued, similar to the results described above for the Morris water maze.
Interestingly, an analog of the Morris water maze reveals memory deficits in humans that parallel findings in rats. Aged subjects were less accurate in locating the target than were the young controls, suggesting deficits in spatial memory that are consistent with the results of rodent experiments.
Age-related morphological and electrophysiological changes Given that neuronal cell death underlies many neurological disorders, an obvious possibility would be that loss of neurons may contribute to age-related deficits in memory function.
Early studies of autopsy material indeed suggested that humans had lost neurons during the aging process; however, these studies measured neuron density and were confounded by differential shrinkage of young vs old brain tissue during histological processing.
More recent studies using modern design-based stereological techniques, which are unaffected by tissue shrinkage, have revealed an overall preservation of neuron number in the brains of aged rats, mice, monkeys, and humans 6 ; one study of hippocampal neuron numbers in the human brain described a loss of cells in the subiculum and hilus of the dentate gyrus, but the granule cells of the dentate gyrus and the principal cells of the hippocampus proper were unaffected.
Several studies have investigated the basic biophysical properties of aged neurons, another likely candidate for age-related declines in function. A variety of basic parameters such as the resting membrane potential, input resistance, membrane time constant, and certain characteristics of excitatory postsynaptic potentials EPSPs 37 were investigated in both young and old rats, but the results of these studies predominantly show that basic electrophysiological properties of aged neurons compared with young neurons are preserved.
The preservation of neurons in both numbers and basic cellular properties leaves open the possibility that the cause of age-related alterations in memory function is rooted in the functional connections between these preserved elements.
In fact, this is where most changes are observed. Concurrent with these observations is a decrease in the amplitude of the presynaptic fiber potential, which suggests a reduction in the number of perforant path axon collaterals passing through the dentate gyrus.
In the CA1 subfield of the hippocampus, different alterations of the functional connections are evident. In this subfield, there is no loss of synapses 10 and no age-related change in the presynaptic fiber potential from the incoming Schaffer collaterals 11 ; yet, there is still a reduction in the field EPSP of CA1 principal cells.
An electron microscopic study of Schaffer collateral synapses in aged rats supports this view. Reductions in postsynaptic density area may contribute to the observed reduction in field EPSP in the CA1 subfield of aged rats. Because the unitary EPSPs are not different in size between young and old rats, these data suggest that the synapses with reduced postsynaptic densities are silent.
Age-related changes in hippocampal synaptic plasticity Inthe Canadian psychologist Donald Hebb, PhD, proposed a means by which synapses could be modified and thus perform the role of information storage.Home Essays Neurobiological Changes Neurobiological Changes Resulting from Psychotherapy Topics: Brain, Cerebrum, Limbic system Pages: 6 ( words) Published: April 24, A Review of the Neurobiological Effects of Psychotherapy for Depression.
rizes the neurobiological changes that occur dur- be a result of methodological limitations in mea-. The Neurobiology of Psychotherapy.
Randon Welton, MD; Jerald Kay, MD The psychiatric community should also look into the neurobiological changes that accompany and may be responsible for an intervention’s effect. Gleich T, Lorenz RC, et al. Playing Super Mario induces structural brain plasticity: gray matter changes resulting from.
Rigidly adhering to one way of thinking or approaching therapy often limits results and misses the whole picture, and may result in an approach that feels foreign or false to the patient. Neurobiological Changes Resulting from Psychotherapy?The effects of psychotherapy and the tools related to its effect have typically been investigated by measuring changes in symptoms, psychological abilities, personality, and social functioning.
"hi-jacked" by these neurobiological changes, and the trauma victim responds before the "thinking" part of the brain (i.e., cerebral cortex) can weigh threats.
The resultant hypervigilance seen in trauma victims can cause them to go.