Review Article

Botanicals as Modulators of Neuroplasticity: Focus on BDNF

Table 1

Brief description of the behavioral test used in the studies reported.

TestProtocolParametersMeaningReferences

Depression
 AnhedoniaSucrose consumption/intakeAnimals can choose to drink water or 1% sucrose.Amount of sucrose consumed and preference for water/sucroseThe anhedonic phenotype is characterized by a reduction of sucrose intake/preference.[25, 26, 64, 99, 100, 102, 103, 119, 123]

DespairForced swimming test (FST)Animals are put in a vessel filled with water.Latency to floating, swimming timeDespair behavior is associated with shorter latency to float and with less swimming time.[27, 55, 56, 64, 72, 87, 100103, 105, 106, 123, 126, 130, 140]
Tail suspension test (TST)Animals are suspended by the tail.Immobility timeDespair is correlated with an increase in the immobility time.[27, 64, 100, 101, 105, 130]

AnxietyOpen field (OF) testAnimals are free to explore an empty arena.Time of exploration and number of rearingAnxiety behavior is correlated with a reduction of exploration and rearing.[25, 26, 40, 63, 73, 74, 79, 100, 101, 118, 139, 140]
Shuttle box escape testAnimal can avoid an electric shock by running in the other room of the apparatus.Number of escapesAnxiety is characterized by the increased number of escape failures.[25, 27]
Elevated plus mazeAnimals are free to explore a maze with two open and two close arms.Time spent in the open armsThe time spent in the open arms is inversely correlated with anxiety.[73, 104, 106, 140]
Novelty-induced hyponeophagia (NIH) testAfter 48 h food deprivation, animals are put into a cage containing food in the center.Latency to feedingIncrease latency is associated with an anxious phenotype.[99, 101]
Learned helplessnessAnimals learn to associate an electric shock with a tone.Freezing timeTime of freezing is directly correlated with anxiety.[101]

CognitionNovel object recognition (NOR) testAnimals must discriminate between a novel (n) and a familiar (F) object.Time exploring the two objects and NOR index (n − F)/(n + F) + 100To correctly perform it, the animals must spend more time exploring the novel object. Improvement of cognition is reflected by a higher NOR index, while worsening is reflected by a lower NOR index.[29, 30, 40, 42, 43, 74, 78]
Y mazeAnimals are put in a maze (Y-shaped), and they must recognize the novel arm (which is closed in the trial phase).Time exploring the new armAn increase in time exploring the new arm is an index of a correct cognitive performance.[29, 78, 113]
Fear conditioningAnimals learn to associate a cue (context or tone) to an electric shock.Freezing time when the cue is presented without a shockTime of freezing is directly correlated with memory.[29, 33, 77]
Morris water maze (MWM)The animals learn to escape onto a hidden platform using this swimming-based model.Time spent in the target quadrant (where the platform is).Preserved spatial memory corresponds to increased time in the correct quadrant.[30, 45, 76, 77, 80, 90, 109, 110, 118, 121, 135, 145]
Spontaneous alternation testAnimals are placed in the center of a four-arm maze and are free to explore.Percentage of alternations in the entry of the different arms.The spontaneous alternation is used as memory task.[47, 90]
Radial arm water maze (RAWM)Animals must find a submerged platform at the end of one of the six arms of the maze, aided by the fixed visually cues on the walls of the room.Number of errorsReduction of errors is related to a better cognitive performance.[52, 91, 139]