cortex, and subgenual parts of the anterior cingulate cortex. Prominent connections to the areas of heteromodal association in the front, temporal and parietal lobes. Strong reciprocal connections to the dorsolateral prefrontal cortex (roughly Brodmann area 46) and the frontal poles (Brodmann areas 10 and 11). Less prominent connections to Brodmann areas 9/46, 8 and 9. Connections to the dorsal parts of the anterior cingulate cortex. Dense connections to the thalamus in the form of a continuous strip that crosses numerous pulvinar nuclei and the striatum. As is true in other areas of the posteromedial cortex, the posterior cingulate cortex has no apparent connections to primary sensory or motor areas. Thus, it is unlikely to be involved in low-level sensory or motor processing. Human structure While many of the connections in non-human primates may be present in humans, they are less well documented. Studies have shown strong reciprocal connections to medial temporal lobe memory structures, such as the entorhinal cortex and the parahippocampal gyrus, the latter being involved in associative learning and episodic memory. In humans, the PCC is also connected to areas involved in emotion and social behavior, attention (the lateral intraparietal cortex and precuneus), learning and motivation (the anterior and lateral thalamic nucleus, caudate nucleus, orbitofrontal cortex and anterior cingulate cortex). Function The posterior cingulate cortex is highly connected and one of the most metabolically active regions in the brain, but there is no consensus as to its cognitive role. Cerebral blood flow and metabolic rate in the PCC are approximately 40% higher than average across the brain. The high functional connectivity of the PCC, signifies extensive intrinsic connectivity networks (networks of brain regions involved in a range of tasks that share common spatio-temporal patterns of activity). Emotion and memory The posterior cingulate cortex has been linked by lesion studies to spatial memory, configural learning, and maintenance of discriminative avoidance learning. More recently the PCC was shown to display intense activity when autobiographical memories (such as those concerning friends and family) are recalled successfully. In a study involving autobiographical recollection, the caudal part of the left PCC was the only brain structure highly active in all subjects. Furthermore, the PCC does not show this same activation during attempted but unsuccessful retrieval, implying an important role in successful memory retrieval (see below: Alzheimer's Disease). The posterior cingulate cortex has also been firmly linked to emotional salience. Thus, it has been