Limbic system

Our memories have contexts with specific places and times

gettingwell4 5+ stars Premium, Hippocampus, Limbic system, Memory

This 2014 rodent study was of the place aspect of a memory’s context. The researchers found that the CA3 segment of the hippocampus stored a unique representation of the location where the memory was formed:

“Place cells are hippocampal cells (in CA3) that fire specifically when the animal is at a certain location.

Form unique representations for every single environment.

When the animal was introduced to one of the rooms a second time the spatial map from the first exposure was reactivated.”

Our memories are formed within a specific context tied in the time aspect of a memory’s context:

“Hippocampal neurons not only track time, but do so only when specific contextual information (e.g., object identity/location) is cued.”

Our memories have contexts with specific places and times. Accessing a memory’s specific context would be a necessary part of accessing a full memory.

http://www.pnas.org/content/111/52/18428.full “Place cells in the hippocampus: Eleven maps for eleven rooms”

Our memories are formed within a specific context

gettingwell4 4-5 stars Advanced knowledge, Hippocampus, Limbic system, Memory

This 2014 primate study provided evidence that our memories are formed within a specific context:

“The hippocampus, a structure known to be essential to form episodic memories, possesses neurons that explicitly mark moments in time.

We add a previously unidentified finding to this work by showing that individual primate hippocampal neurons not only track time, but do so only when specific contextual information (e.g., object identity/location) is cued.”

As the study may apply to humans, it would follow that accessing a memory’s specific context would be a necessary part of accessing a full memory.

http://www.pnas.org/content/111/51/18351.full “Context-dependent incremental timing cells in the primate hippocampus”

Sorry to disable comments, but this post has somehow become a spam target. Readers can comment on Our memories have contexts with specific places and times which incorporates this study’s findings.

Problematic research on human brain development

gettingwell4 < 0 Detracted from science, Brain development, Cerebrum, Limbic system , ,

This 2013 UK human study provided details of the growths of infants’ cerebral and limbic system structures. With 55 of the 65 infants in the study born prematurely, the UK researchers found:

“Rapidly developing cortical microstructure is vulnerable to the effects of premature birth, suggesting a mechanism for the adverse effects of preterm delivery on cognitive function.”

The infants’ first set of measurements were taken from 27 to 46 weeks after birth. Follow-up measurements were taken when the infants were two years old.

Only the politically-correct adverse effects on brain development were included in the study, which led to the researchers making only politically-correct findings. Is this what we want from publicly funded scientific research?

  • Although 40 of the 65 infants experienced Caesarian deliveries, no attempt was made by the researchers to study any effects on brain development of their delivery method, an omission presumably due to the political incorrectness of suggesting any adverse effects to non-vaginal deliveries.
  • Similarly disregarded for analysis were the effects on brain development in 14 infants of preeclampsia, a serious complication of pregnancy associated with the development of high blood pressure and protein in the urine.
  • Also disregarded for analysis were the effects on brain development in 13 infants of chorioamnionitis, a condition in pregnant women in which the membranes that surround the fetus and the amniotic fluid are infected by bacteria.

Further, was this all we should expect from the peer review process? The data was presumably there for the reviewers to go back to the researchers and suggest analysis of something other than the predetermined agenda.

http://www.pnas.org/content/110/23/9541.full “Development of cortical microstructure in the preterm human brain”

Conscious mental states should not be the first-choice explanation of behavior

gettingwell4 4-5 stars Advanced knowledge, Amygdala, Cerebrum, Hippocampus, Limbic system, Memory , ,

Here are some 2014 ruminations by Joseph LeDoux, the grandfather of studies of the amygdala. He attempted to disambiguate feeling brain structures’ activations and responses from ideas of what feelings are, specifically regarding fear:

“Damage to the hippocampus in humans disrupts explicit conscious memory of having been conditioned but has no effect on fear conditioning itself, whereas damage to the amygdala disrupts fear conditioning but not the conscious memory of having been conditioned.

Conscious mental states should not, in the absence of direct evidence, be the first-choice explanation of behavior.

Neither amygdala activity nor amygdala-controlled responses are telltale signatures of fearful feelings.

Conscious fear can cause us to act in certain ways, but it is not the cause of the expression of defensive behaviors and physiological responses elicited by conditioned or unconditioned threats.”

http://www.pnas.org/content/111/8/2871.full “Coming to terms with fear”