The effects of noninvasive neurostimulation on brain structure and function in chronic poststroke aphasia are poorly understood. We investigated the effects of intermittent theta burst stimulation (iTBS) applied to residual language-responsive cortex in chronic patients using functional and anatomical MRI data acquired before and after iTBS. Lateralization index (LI) analyses, along with compar...

In radical behaviorism, the difference between overt and covert responses does not depend on properties of the behavior but on the sensitivity of the measurement tools employed by the experimenter. Current neuroscientific research utilizes technologies that allow measurement of variables that are undetected by the tools typically used by behavior analysts. Data from a specific neuroscientific t...

Many experiments provide evidence that practicing retrieval benefits retention relative to conditions of no retrieval practice. Nearly all prior research has employed retrieval practice requiring overt responses, but a few experiments have shown that covert retrieval also produces retention advantages relative to control conditions. However, direct comparisons between overt and covert retrieval...

BACKGROUND Overt stroke after non-cardiac surgery has a substantial impact on the duration and quality of life. Covert stroke in the non-surgical setting is much more common than overt stroke and is associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after non-cardiac, non-carotid artery surgery. METHODS We undertook a prospective, internat...

It has recently been demonstrated that a cortical network of visuospatial and oculomotor control areas is active for covert shifts of spatial attention (shifts of attention without eye movements) as well as for overt shifts of spatial attention (shifts of attention with saccadic eye movements). Studies examining activity in this visuospatial network during attentional shifts at a single rate ha...

OBJECTIVE We investigated whether covert unimanual response preparation triggers attention shifts, as postulated by the premotor theory of attention, and whether these result in spatially specific modulations of visual and auditory processing. METHODS Visual response cues instructed participants to prepare to lift their left or right index finger in response to a subsequent target stimulus. I...

Covert channels use stealth communications to compromise the security policies of systems. They constitute an important security threat since they can be used to exfiltrate confidential data from networks. TCP/IP protocols are used everyday and are subject to covert channels problems. Covert channels are used for the secret transfer of information. Encryption only protects communication from be...

Cloud computing relies on hypervisors to isolate virtual machines running on shared hardware. Since perfect isolation is difficult to achieve, sharing hardware induces threats. Covert channels were demonstrated to violate isolation and, typically, allow data exfiltration. Several covert channels have been proposed that rely on the processor’s cache. However, these covert channels are either slo...

Network packet length covert channel modulates secret message bits onto the packet lengths to transmit secret messages. In this paper, a novel network packet length covert channel is proposed. The proposed scheme is based on the empirical distribution function of packet length series of legitimate traffic. Different from the existing schemes, the lengths of packets which are generated by the co...

The boom of covert communication coincides with the appearance and growth of the Internet. The rapid spread of computer networks and shift to digitization of media has created a very favourable environment for covert communication. In this paper, some Covert communication techniques have been described. Covert or secure communication includes methods such as cryptography, steganography and wate...