Table 1.
Cognitive and behavioral effects after selective lesions to the mediodorsal thalamus in non-human primates (rhesus macaque monkeys).
| Study | Lesion to | Task | Effect |
|---|---|---|---|
| Isseroff et al., 1982 | Bilateral MD – ablations | Spatial delayed alternation | Impaired |
| Spatial delayed response | Impaired | ||
| Aggleton and Mishkin, 1983 | Bilateral MD – ablations | Object recognition memory | Impaired |
| Object-reward associations | Impaired | ||
| Zola-Morgan and Squire, 1985 | Bilateral MD – ablations | Delayed non-match to sample | Impaired |
| Pattern discriminations | Not Impaired | ||
| Parker et al., 1997 | Bilateral MDmc – ablations | Object recognition memory | Impaired, if large numbers of objects used |
| Gaffan and Parker, 2000 | Bilateral MDmc – ablations | Learnt 20 novel object-in-place scene discriminations within a session | Impaired |
| Gaffan and Parker, 2000 | Bilateral MDmc – ablations | Learnt object-reward associations within a session | Impaired |
| Mitchell et al., 2007a | Bilateral MDmc – neurotoxins | Learnt 20 novel object-in-place scene discriminations within a session | Impaired–increased switching not perseverative responding |
| Mitchell et al., 2007a | Bilateral MDmc – neurotoxins | Implementation of preoperatively acquired strategy | Not Impaired |
| Mitchell et al., 2007b | Bilateral MDmc – neurotoxins | Learnt 60 object-reward associations across sessions to criterion | Not Impaired |
| Mitchell et al., 2007b | Bilateral MDmc – neurotoxins | Food devaluation | Impaired |
| Mitchell and Gaffan, 2008 | Bilateral MDmc – neurotoxins | Retention of 300 preoperative acquired object-in-place scene discriminations | Not Impaired |
| Mitchell and Gaffan, 2008 | Bilateral MDmc – neurotoxins | Postoperative learning of 100 novel object-in-place scene discriminations across sessions | Impaired |
| Mitchell et al., 2008 | Bilateral MDmc – neurotoxins + fornix transection | Retention of 300 preoperative acquired object-in-place scene discriminations | Impaired, combined damage to two interdependent neural circuits caused retention deficits |
| Mitchell et al., 2008 | Bilateral MDmc – neurotoxins + fornix transection | Postoperative learning of 100 novel object-in-place scene discriminations across sessions | Impaired, greater deficit compared to bilateral MDmc lesions alone–Mitchell and Gaffan, 2008 |
| Izquierdo and Murray, 2010 | Unilateral MDmc – neurotoxic + contralateral amygdala + orbitofrontal cortex | Food devaluation | Impaired |
| Browning et al., 2015 | Unilateral MDmc – neurotoxins | Learning 20 novel object-in-place scene discriminations within a session | Impaired |
| Browning et al., 2015 | Unilateral ventrolateral PFC and orbitofrontal cortex ablation | Learning 20 novel object-in-place scene discriminations within a session | Not impaired |
| Browning et al., 2015 | Contralateral ventrolateral PFC and orbitofrontal cortex X MDmc – neurotoxins | Learning 20 novel object-in-place scene discriminations within a session | Impaired |
| Browning et al., 2015 | Contralateral ventrolateral PFC and orbitofrontal cortex X MDmc – neurotoxins | Food devaluation | Impaired |
| Browning et al., 2015 | Ipsilateral ventrolateral PFC and orbitofrontal cortex + MDmc – neurotoxins | Learning 20 novel object-in-place scene discriminations within a session | Not impaired |
| Browning et al., 2015 | Ipsilateral ventrolateral PFC and orbitofrontal cortex + MDmc – neurotoxins | Food devaluation | Impaired |
| Chakraborty et al., 2016 | Bilateral MDmc – neurotoxins | Learning novel 3-choice probabilistic object-reward associations within a session and reversals | Impaired–increased switching. Disrupted rapid updating of next choice response based on recent choice history |