Post-Trial Sleep in Old Rats Trained for a Two-Way Active Avoidance Task

Wistar rats retain for months memory of active avoidance learned behaviour

“…Unfortunately, nothing is known about cerebral DNA and protein neosynthesis during avoidance conditioning in aged rats. However, our previous data demonstrated that old rats do not present those posttraining sleep modifications (Ambrosini et al, 1997) which correlate with memory processing. (Ambrosini et al, 1988a(Ambrosini et al, , b, 1992(Ambrosini et al, , 1995Langella et al, 1992;Mariucci étal, 1992).…”

“…These data lead us to assume that acquisition of active avoidance behaviour in young animals is accompained by stable functional changes in the cerebral networks unaffected by aging. Such a long-term memory might be the result of neosynthesis of nucleic acids and proteins and of specific changes in postacquisition sleep, that in young animals have been demonstrated to correlate positively with avoidance learning (Scaroni et al, 1983;Ambrosini et al, 1988aAmbrosini et al, , b, 1992Ambrosini et al, , 1995Ambrosini et al, , 1997Tsukada, 1988;Langella et al, 1992;Mariucci et al, 1992). These molecular and electrophysiological events could be an expression of the cerebral plasticity which makes memory processes possible in young animals, whereas its reduction throughout life could be responsible for age-dependent learning impairment (Wallace et al, 1980).…”

“…Male (n = 39) and female (w = 56) 3-month-old Wistar rats (Charles River Italia, Calco, Italy) were massively (3.5 h) trained for a two-way active avoidance task in an automated shuttle-box (U. Basile, Comerio, Italy) and subjected to a retention test (30 min) the following day, according to the procedure followed in all of our previous studies (Scaroni et al, 1983;Ambrosini et al, 1988aAmbrosini et al, , b, 1992Ambrosini et al, , 1995Ambrosini et al, , 1997Langella et al, 1992;Mariucci et al, 1992). In addition to freezing, escape, and avoidance responses, intertrial crossings were also automatically recorded in order to evaluate spontaneous locomotory and search activity.…”

“…For some years, our laboratory has also been interested in evaluating the role of cerebral DNA and sleep during avoidance response acquisition and retention (Scaroni et al, 1983;Ambrosini et al, 1988aAmbrosini et al, , b, 1992Ambrosini et al, , 1995Ambrosini et al, , 1997Langella et al, 1992;Mariucci et al, 1992). On the whole, our studies demonstrated that avoidance learning influences synthesis of cerebral DNA and produces significant effects on postacquisition sleep.…”

“…In fact, middle-aged Wistar rats (8 months) of both sexes mostly expressed escape response during training and few avoidances (maximum 20%) in the test period (unpublished data). Moreover, old male Wistar rats (27 months) displayed a vast majority of freeezing responses, few escapes and occasional avoidances (1 or 2 per training period) in both training and test sessions (Ambrosini et al, 1997).…”