Was this presentation tone-deaf?
No shock was administered and freezing was scored for 2 minutes after the tone presentation (tone-elicited freezing, post-tone freezing).
In contrast to the standard single ambiguous tone tests which likely engage mechanisms that compare the presented tone to a tone-outcome distribution retrieved from memory, we reasoned that simultaneous presentation of both training tones would engage attentional mechanisms such that decisions might reflect biases in attention to one or other tone.
Little empiric evidence is available to guide how e-mail presentation style, tone, and content affect e-mail recipients and whether these factors impact opinions about the sender and the rapidity of response.
The presentation of tone and shock stimuli in all training and testing sessions was controlled by GraphicState software (Coulbourn Instruments).
The SMARC task involved the presentation of tones of 1000 ms duration.
This program controls both conditioned stimulus (CS) presentations (a tone produced by loudspeakers located on the distal walls of the compartments) and unconditioned stimulus (US) – electric shock deliveries (to the animals' feet through the compartment floor, by a Solid State Shocker/Distributor, Coulbourn Instruments Inc. Lehigh Valley, PA, USA).
These results suggest that SOMs may adapt at a faster time scale than PVs with repeated presentation of tones.
Also, all mice froze longer during the presentation of the tone (F 1,73) = 208.2, P < 0.001, tone effect); however the level of freezing to tone depended on genotype (F 1,73) = 33.4, P < 0.001, genotype × tone interaction) and age (F 2,73) = 3.3, P < 0.05, age × tone interaction).
Upon tone presentation, homozygote rats presented significantly lower freezing responses compared to non-transgenic animals (F2,19 = 3.37; p < 0.05).
In the 129SVE strain, freezing behavior before presentations of tone-shock pairings was minimal and did not differ across the genotypes (F2,51=0.53, P=0.589), but significantly less freezing was observed in both heterozygous and knockout mice, compared with their wild-type littermates, in the periods following the three tone-shock associations and after the third association.
