However, if RSC represents

each permanent item in a given view, then it could play a key role in detecting and mapping individual landmarks as we encounter them in our surroundings. This operation could be crucial for successful navigation, as the very building blocks of any representation of an environment Ponatinib ic50 are the most stable items within it. To test the nature of RSC processing, we had good and poor navigators view quartets of outdoor items (Fig. 1). The stimuli differed in terms of how many of their four items were permanent, i.e., with a fixed location in the environment – they contained either no, 1, 2, 3, or 4 permanent items. We used multi-voxel pattern analysis (MVPA; Chadwick et al., 2012, Haynes and Rees, 2006 and Norman et al., 2006) to assess whether information about the number of permanent items in view could be decoded from activity in RSC and, if so, whether this differed between good and poor navigators. The quartets were carefully designed such that variations in landmark size and visual salience could be assessed by the same method, allowing us to determine

whether any patterns of response observed in RSC were specific to item Cyclopamine solubility dmso permanence. Thirty-two, right-handed, healthy participants (16 females, mean age 23.5 years, SD 2.5) took part in the experiment. All had normal or corrected to normal vision, were highly proficient in English and gave written informed consent in accordance with the local research ethics committee. None of the participants had

taken part in any of our previous studies of item permanence. clonidine Each stimulus comprised four different everyday outdoor items, with each item enclosed by a grey outline on a white background, and laid out in a grid (Fig. 1). The stimuli differed in terms of how many of their four items were permanent – they contained either no, 1, 2, 3, or 4 permanent items (giving 5 category types). Permanent items were defined as those consistently rated as ‘never moving’ by an independent set of participants from previous behavioural experiments (Auger et al., 2012). There were 20 stimuli for each of the 5 category types, giving 100 stimuli in total. We ensured that across the trials of each condition, the non-permanent elements were sampled from the full range of permanence ratings (excluding those that ‘never moved’). The stimuli not only varied according to the number of permanent items they contained; their items also varied in terms of real-world size and visual salience. The size and visual salience of items was also determined by an independent set of participants from the previous behavioural experiments (Auger et al., 2012). In designing the stimuli we ensured a full range of values of these two other landmark features, from the very smallest to largest, and from least to most salient items. This allowed us to also group the 100 stimuli into 5 categories for size and 5 for visual salience.