Research digest
The research digest
Every study below used the Morris water maze. We read each original article and summarised it in fresh words; follow the link for the full paper or report.
An underactive thyroid chips away at memory in stages
Male Wistar rats were made hypothyroid with propylthiouracil for 6, 10 or 14 weeks. Mood-like changes came first (open-field movement roughly halved at six weeks), object recognition slipped next, and only the 14-week group struggled in the water maze, taking about twice as long to find the platform and spending 40% less time in its quadrant. Hippocampal GLUT4 protein climbed while its mRNA stayed flat, and levothyroxine undid the changes. A tidy reminder that how long a model runs can decide which test catches it.
Read the original at Endokrynologia PolskaTwo plant diterpenes tested against amyloid damage
Pseudolaric acids A and B shielded cultured PC12 cells from amyloid-beta-induced cell death and damped inflammation in stimulated microglia and macrophages. The team then moved to mice given aluminium chloride as an Alzheimer's-like model, where pseudolaric acid B improved spatial learning and memory in the Morris water maze. The authors say plainly that the signalling story still has to be confirmed in living animals.
Read the original at ACS Pharmacology & Translational ScienceA brain support cell that seems to set the body's pace of ageing
FGF13 falls with age in the brain's non-neuronal cells. Deleting it from astrocytes in ageing mice made their water maze performance worse and raised markers of senescence in organs from the skin to the kidney. Boosting it did the opposite: older mice swam the maze about as well as young ones, did better in the elevated plus maze and open field and showed lower IL-6 and IFN-gamma. The study, reported from Aging Cell, points to more autophagy via a partner protein called Phafin2.
Aging Cell
Read the original at Lifespan.ioTreadmill time helps rat brains bounce back after morphine
Male rats, some castrated, received morphine twice a day for ten days and then 28 days of mild or moderate treadmill running, with or without testosterone. Withdrawal and castration each dented spatial learning, spatial memory and avoidance memory, and both lowered BDNF in the hippocampus and prefrontal cortex. Both exercise levels helped, moderate running more so, while testosterone's extra benefit was partial and depended on the group. Published in Behavioral and Brain Functions.
Behavioral and Brain Functions
Read the original at Bioengineer.orgToo much salt, and older mice lose their way
Twelve-month-old male mice ate chow with 8% salt or a normal 0.5% for two months, ten per group, with testers blinded. The salty group learned the water maze more slowly, with gaps opening on days four and five, and did worse on every probe measure: crossings, time over the old platform spot, distance and target-quadrant time. Swim speed and open-field behaviour didn't differ, which is exactly the control you want before calling it a memory effect. The authors link the deficit to more amyloid-beta and a mitochondrial clean-up response that tried, and failed, to keep up. Published in Frontiers in Neurology.
Frontiers in Neurology
Read the original at Bioengineer.orgHippocampal navigation can run on habit
Rats (20 males, 22 females) learned a maze where the same left or right turn led to milk or to water, depending on where the choice was made. After a day without water, only rats that re-experienced the maze while thirsty switched towards the water-linked turns; rats that merely tasted both drinks while thirsty kept heading for milk, even when the task needed the hippocampus. Not a water maze study in the swimming sense, but a sharp point for anyone who reads every direct path as goal-directed thinking.
Read the original at The Journal of NeuroscienceExercise order matters, and BDNF doesn't tell the whole story
Forty male Wistar rats were split into five groups for eight weeks: endurance running, rotarod training, each combination in either order, or no training. Endurance work gave the highest hippocampal BDNF, yet the group that did rotarod first and endurance second learned the water maze fastest. Probe trials, object recognition and passive avoidance showed no group differences. The neat lesson: a molecular marker and a behavioural score won't always rise together.
Read the original at Bioengineer.orgHuperzine A and a less obvious memory circuit
In mice with narrowed blood supply to the brain (bilateral carotid occlusion), huperzine A improved water maze, novel object and Y-maze scores without changing how much the animals moved. The China Pharmaceutical University team traced the effect to more acetylcholine in the dorsal striatum, acting through alpha-7 nicotinic receptors and a striatum to substantia nigra pathway. Delivering huperzine A, acetylcholine or donepezil straight into the dorsal striatum reproduced the benefit. The paper appeared in Targetome.
Targetome
Read the original at EurekAlert!A nasal treatment helped ageing males, not females
SAMP8 mice, a fast-ageing strain, received the Euphorbia-derived diterpene ER272 by nose for eight weeks from four months of age. Both sexes were impaired in the water maze and in object discrimination, but only treated males recovered, spending more time in the target quadrant at probe. Open-field testing ruled out changes in general movement. The case for testing both sexes, in one paper. Published in Aging Cell.
Aging Cell
Read the original at Bioengineer.orgA liver-acting drug, a better memory in Alzheimer's model mice
The pan-AMPK activator MK-8722 was given to APP/PS1 mice aged six to eight months. It switched on AMPK in the liver but not the hippocampus, yet treated mice did better on hippocampus-dependent spatial memory and had more mature dendritic spines. Long-term potentiation didn't change. Blood lipid and metabolite profiles that were off in the model mice moved partway back to normal, hinting that metabolism outside the brain can nudge memory inside it.
Read the original at Journal of NeurochemistryA muscle-powered robot the size of a stick of gum
A different kind of water maze: MIT engineers built a flat gel strip with fins of light-sensitive muscle cells. Flash one fin and it contracts, so the robot can be steered through a small obstacle course. Top speed is about four body lengths a minute, roughly the cruising pace of a sixgill shark. For tracking fans, it's a fresh case of following a swimmer frame by frame.
Read the original at NotebookcheckPressing on the shinbone helped injured brains recover
Researchers gently compressed the shinbones of mice, 300 times at two per second, five days a week, after brain injury. More treated mice survived, damage was smaller, and they found the hidden platform in a water maze better than untreated mice. The effect needed a pressure sensor called PIEZO1 in bone cells, serum from treated mice protected other injured mice, and the approach also helped miniature pigs. Published in Nature Neuroscience.
Nature Neuroscience
Read the original at ScienceAlertA carbon football that calms the brain after radiation
A team at UTHealth Houston gave mice a single oral dose of a water-soluble C60 fullerene, C60-ser, a day after cranial irradiation. It restored spatial working memory and damped chronic brain inflammation. The most telling test was Y-maze alternation, and the authors suggest adding the Morris water maze next. Published in Biomedical Microdevices, with an eye on cancer patients and even deep-space crews.
Biomedical Microdevices
Read the original at Bioengineer.orgNewborn anaesthesia: the Y-maze caught what the water maze didn't
Seven-day-old rats had two hours of sevoflurane or propofol. Both raised hippocampal caspase-3 and left a lasting working-memory dip in the Y-maze at day 42, yet the Morris water maze showed no difference. Metabolomics found drug-specific fingerprints: six metabolites stayed high after propofol, and one phosphatidylcholine stayed low after sevoflurane. A useful case for running more than one test.
Read the original at Scientific ReportsIcariin and the stressed nucleolus
Icariin, the main active compound of the herb Herba Epimedii, was tested in APP/PS1 mice and in cultured microglia. In the water maze (four trials a day for four days, then a probe and a contraposition exploration test), treated mice crossed the old platform spot more often and swam distances closer to healthy controls, though the time to find the platform didn't clearly improve. The authors connect the effect to relief of nucleolar stress, the cell's ribosome factory under strain.
Read the original at Bioengineer.orgAfter blood loss and rescue, memory hinges on microglia
Male mice that survived haemorrhagic shock and resuscitation were tested on object recognition at day 31 and in the water maze from day 32. They took longer to find the platform, crossed its old spot less and spent less time in the target quadrant, while swimming at normal speed. Blocking the NLRP3 inflammasome in microglia brought performance back. Published in Behavioral and Brain Functions.
Behavioral and Brain Functions
Read the original at Bioengineer.orgAn Astragalus saponin after traumatic brain injury
A Lanzhou University group gave astragaloside IV to male C57BL/6 mice after controlled cortical impact, at 40 or 80 mg/kg every other day for four weeks, with GM1 ganglioside as the comparison treatment. The 40 mg/kg dose shortened water maze escape times, and NMDA receptor blockers cancelled the benefit, pointing to glutamate signalling. Published in Frontiers in Pharmacology.
Frontiers in Pharmacology
Read the original at Bioengineer.orgAnabolic steroid, foggier spatial memory, and a careful design
Twenty-seven male Wistar rats received nandrolone at 5 or 15 mg/kg, or vehicle, every third day for 22 days. Animals were coded, the tester was blind and a separate person ran the statistics. In the water maze (four trials a day for four days, platform 1 cm under the surface) the probe trial showed a memory deficit while movement stayed normal, and hippocampal calcineurin rose. Published in Behavioral and Brain Functions.
Behavioral and Brain Functions
Read the original at Bioengineer.orgApigenin, noradrenaline and the brain's lactate supply
Eight weeks of D-galactose, a common accelerated-ageing model, impaired mice on object recognition, the water maze and the Y-maze. Apigenin, a flavonoid found in several medicinal herbs, improved all three. The Heilongjiang team links this to the GPR30 receptor, more norepinephrine release and more brain lactate, and they flag limits around the model and the sex of the animals. Published in Frontiers in Pharmacology.
Frontiers in Pharmacology
Read the original at Bioengineer.orgSoft food, older mice and the hippocampus's support cells
Female Swiss albino mice aged 6 or 18 months lived on hard pellets, soft food, or a switch between them, and astrocytes in one hippocampal layer were counted and measured. The team reanalysed earlier water maze data as a single contrast index, and older mice scored lower on day four. A study about texture, chewing and glia that uses maze data as its behavioural anchor. Published in Behavioral and Brain Functions.
Behavioral and Brain Functions
Read the original at Bioengineer.orgA 14-herb formula in rats with reduced brain blood flow
Rats with both carotid arteries tied off (9 sham, 12 model, 13 treated) received Modified Dioscorea Pills for 45 days. In the water maze the treated group pulled away from untreated model rats by day three and crossed the platform site more often at probe. The article is clear that this doesn't establish a treatment for human dementia.
Read the original at Bioengineer.orgCould sea squirts help ageing brains?
Plasmalogens are fats found in cell membranes that decline with age. Aged female mice given plasmalogens from sea squirts for two months did better in a water maze, kept more synapses, showed calmer microglia and even grew thicker, darker coats. Fun, and firmly mouse-only for now.
Read the original at Free Malaysia TodaySeventeen rat studies, one postmenopausal model, very low certainty
A systematic review pooled 17 studies that combined ovariectomy with D-galactose in rats to mimic postmenopausal Alzheimer's-like change. Fifteen agents were tested, eight repurposed drugs and seven herbal products. Escitalopram, dapagliflozin and lapatinib improved water maze results, and dimethyl fumarate improved Barnes maze results, but the reviewers rate the certainty of evidence as very low.
Read the original at Bioengineer.org