Project description:We used a custom-designed microarray and qPCR to characterize the rapid transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to repeated noxious shocks to one side of the body (4 ten-second shocks at 90mA, 30 min ISI), a procedure known to induce a transcription-dependent and long-lasting increase in reflex responsiveness that is restricted to the side of training. One hour after training, pleural ganglia from the trained and untrained sides of the body were harvested; these ganglia contain the sensory nociceptors which help mediate the expression of long-term sensitization memory. Â Microarray analysis from 8 biological replicates suggests that long-term sensitization training rapidly regulates at least 102 transcripts. We used qPCR to test a subset of these transcripts and found that 86% were confirmed in the same samples, and 83% of these were again confirmed in an independent sample (n = 9 animals). Thus, our new microarray design shows very strong convergent and predictive validity for analyzing the transcriptional correlates of memory in Aplysia. Fully validated transcripts include some previously identified as regulated in this paradigm (ApC/EBP and ApEgr) but also include novel findings. Specifically, we show that long-term sensitization training rapidly up-regulates the expression of transcripts which encode a C/EBP gamma, a glycine transporter, and a vacuolar-protein-sorting-associated protein. Within-subjects comparison of trained (Cy5) to untrained (Cy3) pleural ganglia with 8 biological replicates. Each replicate is a trained sample from two animals (right and left trained) and each untrained sample is from the same two aniamls (right and left untrained)
Project description:We used a custom-designed microarray and qPCR to characterize the rapid transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to repeated noxious shocks to one side of the body (4 ten-second shocks at 90mA, 30 min ISI), a procedure known to induce a transcription-dependent and long-lasting increase in reflex responsiveness that is restricted to the side of training. One hour after training, pleural ganglia from the trained and untrained sides of the body were harvested; these ganglia contain the sensory nociceptors which help mediate the expression of long-term sensitization memory. Microarray analysis from 8 biological replicates suggests that long-term sensitization training rapidly regulates at least 102 transcripts. We used qPCR to test a subset of these transcripts and found that 86% were confirmed in the same samples, and 83% of these were again confirmed in an independent sample (n = 9 animals). Thus, our new microarray design shows very strong convergent and predictive validity for analyzing the transcriptional correlates of memory in Aplysia. Fully validated transcripts include some previously identified as regulated in this paradigm (ApC/EBP and ApEgr) but also include novel findings. Specifically, we show that long-term sensitization training rapidly up-regulates the expression of transcripts which encode a C/EBP gamma, a glycine transporter, and a vacuolar-protein-sorting-associated protein.
Project description:We used a custom-designed microarray and qPCR to characterize the persistent transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to a 1-day unilateral LTS training protocol (4 rounds of noxious shock at 30 min intervals, each shock 10s of 1/2s off 1/2on 90mA 60-hz biphasic square-wave shock). Training produced robust sensitization in all animals (measured as an increase in T-SWR response from baseline to 24h after training). Immediately after 24h post-tests, pleural ganglia was harvested. Samples from a left-trained and right-trained animal were combined to smooth out lateralized gene expression. The pleural ganglia contains the VC nociceptors, which are thought to play a primary role in expressing LTS memory.
Project description:We used a custom-designed microarray and qPCR to characterize the persistent transcriptional response to long-term habituation training in the marine mollusk Aplysia californica. Aplysia were exposed to either 3 days of spaced long-term habituation training (10 rounds of stimulation/day; each round = 15 min brushing at a 10s ISI; 15 min rest between rounds); a matched set of controls was not exposed to any brushing (n = 8/group). While reflex responsiveness remained stable in controls, trained animals exhibited a large reduction in siphon-withdrawal duration that was evident at stimulation sites across the entire dorsal surface of the body (head, tail, and siphon). This habituation was retained for at least 24 hours after the end of training. Immediately after 24 hour retention tests, pleural ganglia were harvested from each trained animal and its matched control. The pleural ganglia contain the VC nociceptors, which we confirmed are activated by the brush stimulus used to produce habituation. Microarray analysis from 8 biological replicates suggests that long-term habituation training persistently regulates 21 transcripts. We used qPCR to test a subset of these transcripts and found persistent regulation of an putative Aplysia cornichon homolog.
Project description:We used a custom-designed microarray and qPCR to characterize the transcriptional response that persists 7 days after long-term sensitization training in the marine mollusk Aplysia californica, a time-point at which recall has decayed but savings memory is still possible to induce. Aplysia were exposed to a 1-day unilateral LTS training protocol (4 rounds of noxious shock at 30 min intervals, each shock 10s of 1/2s off 1/2on 90mA 60-hz biphasic square-wave shock). Training produced robust sensitization in all animals (measured as an increase in T-SWR response from baseline to 24h after training). One week (7 days) after training, animals were again post-tested, and showed little-to-no evidence of recall (average change from baseline = -4% on the trained side, -4% on the untrained side). Pleural ganglia were then harvested. Samples from a left-trained and right-trained animal were combined to smooth out lateralized gene expression. The pleural ganglia contains the VC nociceptors, which are thought to play a primary role in expressing LTS memory.
Project description:We used a custom-designed microarray and qPCR to characterize the persistent transcriptional response to long-term habituation training in the marine mollusk Aplysia californica. Aplysia were exposed to either 3 days of spaced long-term habituation training (10 rounds of stimulation/day; each round = 15 min brushing at a 10s ISI; 15 min rest between rounds); a matched set of controls was not exposed to any brushing (n = 8/group). While reflex responsiveness remained stable in controls, trained animals exhibited a large reduction in siphon-withdrawal duration that was evident at stimulation sites across the entire dorsal surface of the body (head, tail, and siphon). This habituation was retained for at least 24 hours after the end of training. Immediately after 24 hour retention tests, pleural ganglia were harvested from each trained animal and its matched control. The pleural ganglia contain the VC nociceptors, which we confirmed are activated by the brush stimulus used to produce habituation. Microarray analysis from 8 biological replicates suggests that long-term habituation training persistently regulates 21 transcripts. We used qPCR to test a subset of these transcripts and found persistent regulation of an putative Aplysia cornichon homolog. Between-subjects comparison of a trained animal to a matched control (matching based on duration of pre-test responsiveness). Conducted with 8 biological replicates, meaning 8 arrays, each comparing 1 trained and 1 matched control.
Project description:We used a custom-designed microarray to characterize the transcriptional response that accompanies longt-term sensitization training in the marine mollusk Aplysia californica. We characterized transcription for a new memory (1 day after training), a forgotten memory (8 days after training) and for a long-term savings memory (8 days after training but 1 day after a reminder that re-instates the sensitization memory). All animals received a 1-day unilateral LTS training protocol (4 rounds of noxious shock at 30 min intervals, each shock 10s of 1/2s off 1/2on 90mA 60-hz biphasic square-wave shock). This produced robust sensitization in all animals (measured as an increase in T-SWR response from baseline to 24h after training). In the forgetting condition, animals received training on day 1, and post-tests on days 7 and 8 showed little-to-no evidence of recall (T-SWR responses on the trained side returned to close to baseline). In the savings condition, animals received training on day 1 that produced strong sensitization, showed forgetting on day 7, and then received a weak bilateral shock as a reminder (day 7), producing a long-term savings memory on day 8 (a re-instatement of the behavioral expression of sensitization on the previously trained side). In the new memory condition, animals received sham training on day 1, then real training on day 7, producing robust sensitization measured on day 8. Pleural ganglia were harvested on day 8. Samples from a left-trained and right-trained animal were combined to smooth out lateralized gene expression. The pleural ganglia contains the VC nociceptors, which are thought to play a primary role in expressing LTS memory.