Selective activation of the ventrolateral prefrontal cortex in the human brain during active retrieval processing

Abstract

The present study examined the role of the prefrontal cortex in retrieval processing using functional magnetic resonance imaging in human subjects. Ten healthy subjects were scanned while they performed a task that required retrieval of specific aspects of visual information. In order to examine brain activity specifically associated with retrieval, we designed a task that had retrieval and control conditions that were perfectly matched in terms of depth of encoding, decision making and postretrieval monitoring and differed only in terms of whether retrieval was required. In the retrieval condition, based on an instructional cue, the subjects had to retrieve either the particular stimulus that was previously presented or its location. In the control condition, the cue did not instruct retrieval but shared with the instructional cues the function of alerting the subjects of the impending test phase. The comparison of activity between the retrieval and control conditions demonstrated a significant and selective increase in activity related to retrieval processes within the ventrolateral prefrontal cortical region, more specifically within area 47/12. These activity increases were bilateral but stronger in the right hemisphere. The present study by strictly controlling the level of encoding, postretrieval monitoring, and decision making has demonstrated a specific increase in the ventrolateral prefrontal region that could be clearly related to active retrieval processing, i.e. the active selection of particular stored visual representations.

Conditional Associative Memory for Musical Stimuli in Nonmusicians: Implications for Absolute Pitch

“…Activation of the mid-ventrolateral prefrontal cortex in this study was most obvious in the S2 chords Ϫ noise contrast and somewhat stronger in the right hemisphere, which, again, is consistent with the tonal nature of stimuli. The locations of our peaks are very similar to those reported by other researchers (Cadoret et al, 2001;Kostopoulos and Petrides, 2003) in studies in which a task required selective postencoding retrieval among various features of a stimulus.…”

The engagement of mid‐ventrolateral prefrontal cortex and posterior brain regions in intentional cognitive activity

“…In addition to the work of Petrides [1994] and others, this result ties in well with the view that the mid-VLPFC is activated under a wide variety of conditions that require control processes (Fig. 3 and Table I; [Braver et al, 2003;Bunge et al, 2001;Cadoret et al, 2001;Cools et al, 2002;Dove et al, 2000Dove et al, , 2006Duncan and Owen, 2000;Houde et al, 2000;Jenkins et al, 1994;Kostopoulos and Petrides, 2003;Langleben et al, 2005;Turk et al, 2004]). Note that the coordinates reported in these studies are anatomically very close to the centre of our regions of interest in the mid-VLPFC (Fig.…”

Ventrolateral and dorsomedial frontal cortex lesions impair mnemonic context retrieval

“…However, the experiment was designed to test the hypothesis that the VLPFC is critical for the disambiguation of mnemonic traces when the relations between stimuli and their contexts are unstable [20][21][22][23]. Patients with lesions to the VLPFC were predicted to be selectively impaired on the unstable context retrieval condition which assesses active controlled retrieval.…”

“…Thus, the engagement of the prefrontal cortex in context/source retrieval is not obligatory and the ventrolateral prefrontal cortex (VLPFC) becomes necessary as ambiguity in item-to-context relations increases. This specific hypothesis was tested with functional neuroimaging, and evidence was provided for selective increases in activity in the VLPFC when human subjects were retrieving specific stimulus features that had occurred in association with multiple contexts [20][21][22][23], but direct evidence of the critical involvement of an area in such retrieval, which can only be provided by lesion studies, is not available.…”

“…This study tested the above predictions by examining the performance of patients with damage to the frontal cortex on three memory retrieval conditions, in which the level of ambiguity between stimulus items and their contexts was manipulated by varying the probability with which a stimulus (word) and a context (background) appeared in relation to one another [20][21][22][23]. Performance of patients with lesions to the frontal cortex was compared with that of patients with temporal lobe lesions that had involved the hippocampus and parahippocampal cortex, as well as healthy control subjects.…”