Introducing the brain: spatial memory in thalamus (Introduction)

by David Turell , Wednesday, May 18, 2022, 15:46 (918 days ago) @ David Turell

From mouse maze studies:

https://www.sciencedaily.com/releases/2022/05/220512092709.htm

"Researchers have identified a circuit in the anterior thalamus that is necessary for remembering how to navigate a maze. This region could offer a promising target for treatments that could help reverse memory loss in older people, without affecting other parts of the brain.

"As people age, their working memory often declines, making it more difficult to perform everyday tasks. One key brain region linked to this type of memory is the anterior thalamus, which is primarily involved in spatial memory -- memory of our surroundings and how to navigate them.

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"The thalamus, a small structure located near the center of the brain, contributes to working memory and many other executive functions, such as planning and attention. Feng's lab has recently been investigating a region of the thalamus known as the anterior thalamus, which has important roles in memory and spatial navigation.

"Previous studies in mice have shown that damage to the anterior thalamus leads to impairments in spatial working memory. In humans, studies have revealed age-related decline in anterior thalamus activity, which is correlated with lower performance on spatial memory tasks.

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"This suggests that the AV neurons are most important for keeping information in mind while it is needed for a task. In contrast, inhibiting the AD neurons disrupted performance during the sample phase but had little effect during the delay phase. This finding was consistent with the research team's earlier study showing that AD neurons are involved in forming memories of a physical space.

"'The anterior thalamus in general is a spatial learning region, but the ventral neurons seem to be needed in this maintenance period, during this short delay," Roy says. "Now we have two subdivisions within the anterior thalamus: one that seems to help with contextual learning and the other that actually helps with holding this information."

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"The researchers then tested the effects of age on this circuit. They found that older mice (14 months) performed worse on the T-maze task and their AV neurons were less excitable. However, when the researchers artificially stimulated those neurons, the mice's performance on the task dramatically improved.

"Another way to enhance performance in this memory task is to stimulate the prefrontal cortex, which also undergoes age-related decline. However, activating the prefrontal cortex also increases measures of anxiety in the mice, the researchers found.

"'If we directly activate neurons in medial prefrontal cortex, it will also elicit anxiety-related behavior, but this will not happen during AV activation," Zhang says. "That is an advantage of activating AV compared to prefrontal cortex.'"

Comment: it is important to know where certain types of mentation are handled in the brain. Geographic sense can be lost. An example is man who impregnated our cows for us. He had a stroke and could travel a short distance from his home to us or to his families' dairy ranch, but had to be driven twenty miles into Houston. This shows all neurons may look alike but have different functions in different brain regions. This has to be designed for proper organization of thought. A chance collection of neurons cannot do this.