The phrase "ahead direction" is not commonly used in written English and may sound awkward.
It could be used in contexts where you want to specify a direction that is forward or in front of something.
Example: "The sign indicated the ahead direction for the next turn."
Alternatives: "forward direction" or "front direction".
Assuming that the user is looking at the desired interlocutor, the sound arriving at both devices is a mixture of the desired source coming from the straight-ahead direction (the green circle) and a combination of undesired sound sources coming from other directions (the gray cloud).
Overall, BOLD response amplitude was significantly higher for a fixed retinotopic location near the vertical meridian when the gaze direction positioned that location nearer the straight-ahead direction (regions at 6° and 14° of distance from straight-ahead direction).
In the current study, we examined whether gaze modulations in early visual areas of humans reflected a bias for the straight-ahead direction along the elevation dimension.
Responses to passive and letterotopy stimuli were qualitatively similar: both groups showed a gain field effect with a response bias for the straight-ahead direction (Fig. 3).
Conversely, the BOLD response evoked by a wedge at a retinotopically fixed lower-field location was reduced when subjects fixated below vs. center/above the straight-ahead direction.
The BOLD response evoked by a wedge at a retinotopically fixed upper-field location was reduced when subjects fixated above vs. center/below the straight-ahead direction.
However, it was unclear whether this distribution showed any consistent spatial structure, as suggested by monkey single unit studies reporting a preference for the straight-ahead direction (Durand et al. 2010, 2012).
Because the straight-ahead direction is likely to be behaviorally relevant, this gain field bias may serve to prioritize events directly in front of the head and the body (Durand et al. 2010, 2012).
In order to see if the spatial distribution of eye position modulations resulted in increased responses for locations nearer the straight-ahead direction, we examined the BOLD response of each of these regions in each subject.
Gaze modulations we observed are consistent with recent proposals that response amplitudes of peripheral neuron in V1 are increased for retinotopic locations nearer the straight-ahead direction (Durand et al. 2010).
