Hippocampal regulation of context-dependent neuronal activity in the lateral amygdala

Shen, Liming and Garrett E. Alexander. Neural correlates of a spatial sensory-to-motor transformation in primary motor cortex. J. Neurophysiol. 77: 1171–1194, 1997. Primary motor cortex (MC) has been strongly implicated in motor processing, but there have been relatively few attempts to determine whether MC may also play a role in either sensory or context-dependent processing. In the present study, neuronal activity in MC was characterized in relation to the planning and execution of visually instructed limb movements whose trajectories were dissociated from their spatial targets. This design permitted the dissociation of neuronal activity related to motor processing from activity related to sensory or context-dependent processing. Two macaque monkeys were trained to perform a visually instructed, delayed reaching paradigm with indirect visual feedback. Subjects used the right forelimb to capture targets presented on a video display by moving a two-dimensional joystick whose position was reflected by a cursor. The target to be captured on each trial was indicated by a visual instruction stimulus (IS), which was separated from a movement-triggering stimulus (TS) by a variable delay. The direction of forelimb movement was dissociated from the location of the target by varying the spatial mappings between joystick and cursor across two conditions, unrotated (0° offset between cursor and limb direction) and rotated (90° offset). Task-related activity was recorded from a total of 180 MC neurons. The focus of this study was on directionally tuned neuronal activity that included phasic, stimulus-related activity following the IS; tonic, set-related activity between IS and TS; and phasic, movement-related activity following the TS. Of the entire sample of MC neurons with directionally tuned activity, 119 cells were tested under both rotation conditions, permitting dissociation of directional responses that depended on target location from those that depended on limb trajectory. Task-related neuronal activity was classified as target dependent if it covaried exclusively with target location across both conditions, and as limb dependent if it covaried exclusively with limb trajectory. Directional activity that did not fulfill the criteria for either target or limb dependence, because of changes across rotation conditions, was classified as complex. Approximately one quarter of MC neurons showed weak, but consistent, stimulus-related activity that was directionally tuned (24%, 29 of 119). Nearly all of the directionally classifiable stimulus-related activity was target dependent (94%, 15 of 16 responses), with the exception of a single limb-dependent response (6%, 1 of 16). A majority of MC neurons showed set-related activity that was directionally tuned (61%, 72 of 119). Of the directionally classifiable set-related activity, there were comparable numbers of target-dependent (37%, 16 of 43) and limb-dependent responses (35%, 15 of 43), with the remainder being complex (27%, 12 of 43). Movement-related activity following the TS was considered to be early or late, depending on whether it preceded or followed the onset of movement. The large majority of MC neurons showed early movement-related activity that was directionally tuned (86%, 102 of 119): among those whose neurons early activity was directionally classifiable, there were only one third as many target-dependent responses (14%, 11 of 79) as limb-dependent responses (43%, 34 of 79), with the remainder being complex (43%, 34 of 79). There was also a large majority of MC neurons that showed late movement-related activity that was directionally tuned (84%, 100 of 119): among those whose late activity was directionally classifiable, there were only one ninth as many target-dependent responses (5%, 4 of 88) as there were limb-dependent responses (41%, 36 of 88), with the remainder being complex (55%, 48 of 88). The instructed delay task employed in this study required a sensory-to-motor transformation through which the instructed target location was associated with a limb movement of the appropriate direction. Over the extended interval between IS and motor response, we observed a gradual decline in the frequency of target-dependent activity and gradual increases in the respective frequencies of both limb-dependent and complex activity. This suggests that MC neurons may play a role in mediating the spatial sensory-to-motor transformation required by the task. The substantial proportions of target-dependent activity observed in this study reinforce the growing evidence that at least some MC neurons do play a role in either sensory or context-dependent processing of spatial information relevant to specific motor tasks.

Download Full-text

Neural Network Model of Context-Dependent Neuronal Activity in Inferotemporal Cortex

The 2006 IEEE International Joint Conference on Neural Network Proceedings ◽

10.1109/ijcnn.2006.1716105 ◽

2006 ◽

Author(s):

A. Suemitsu ◽

M. Morita

Keyword(s):

Neural Network ◽

Neuronal Activity ◽

Network Model ◽

Neural Network Model ◽

Inferotemporal Cortex ◽

Context Dependent

Download Full-text

Forming Impressions of Personality

Social Psychology ◽

10.1027/1864-9335/a000179 ◽

2014 ◽

Vol 45 (3) ◽

pp. 153-163 ◽

Cited By ~ 13

Author(s):

Sanne Nauts ◽

Oliver Langner ◽

Inge Huijsmans ◽

Roos Vonk ◽

Daniël H. J. Wigboldus

Keyword(s):

Impression Formation ◽

Context Dependent

Asch’s seminal research on “Forming Impressions of Personality” (1946) has widely been cited as providing evidence for a primacy-of-warmth effect, suggesting that warmth-related judgments have a stronger influence on impressions of personality than competence-related judgments (e.g., Fiske, Cuddy, & Glick, 2007 ; Wojciszke, 2005 ). Because this effect does not fit with Asch’s Gestalt-view on impression formation and does not readily follow from the data presented in his original paper, the goal of the present study was to critically examine and replicate the studies of Asch’s paper that are most relevant to the primacy-of-warmth effect. We found no evidence for a primacy-of-warmth effect. Instead, the role of warmth was highly context-dependent, and competence was at least as important in shaping impressions as warmth.

Download Full-text

Memorial Consequences of Environmental Context Change in Children and Adults

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000056 ◽

2010 ◽

Vol 57 (6) ◽

pp. 455-461 ◽

Cited By ~ 5

Author(s):

Alp Aslan ◽

Anuscheh Samenieh ◽

Tobias Staudigl ◽

Karl-Heinz T. Bäuml

Keyword(s):

Elementary School ◽

Young Adults ◽

Episodic Memory ◽

Middle Childhood ◽

First Graders ◽

Fourth Graders ◽

Environmental Context ◽

Context Change ◽

Context Dependent

Changing environmental context during encoding can influence episodic memory. This study examined the memorial consequences of environmental context change in children. Kindergartners, first and fourth graders, and young adults studied two lists of items, either in the same room (no context change) or in two different rooms (context change), and subsequently were tested on the two lists in the room in which the second list was encoded. As expected, in adults, the context change impaired recall of the first list and improved recall of the second. Whereas fourth graders showed the same pattern of results as adults, in both kindergartners and first graders no memorial effects of the context change arose. The results indicate that the two effects of environmental context change develop contemporaneously over middle childhood and reach maturity at the end of the elementary school days. The findings are discussed in light of both retrieval-based and encoding-based accounts of context-dependent memory.

Download Full-text