Duifhuis pitch: neuromagnetic representation and auditory modeling

When a high harmonic is removed from a cosine-phase harmonic complex, we hear a sine tone pop out of the perception; the sine tone has the pitch of the high harmonic, while the tone complex has the pitch of its fundamental frequency, f0. This phenomenon is commonly referred to as Duifhuis Pitch (DP). This paper describes, for the first time, the cortical representation of DP observed with magnetoencephalography. In experiment 1, conditions that produce the perception of a DP were observed to elicit a classic onset response in auditory cortex (P1m, N1m, P2m), and an increment in the sustained field (SF) established in response to the tone complex. Experiment 2 examined the effect of the phase spectrum of the complex tone on the DP activity: Schroeder-phase negative waves elicited a transient DP complex with a similar shape to that observed with cosine-phase waves but with much longer latencies. Following the transient DP activity, the responses of the negative and positive Schroeder-phase waves converged, and the increment in the SF slowly died away. In the absence of DP, the two Schroeder-phase conditions with low peak factors both produced larger SFs than cosine-phase waves with large peak factors. A model of the auditory periphery that includes coupling between adjacent frequency channels is used to explain the early neuromagnetic activity observed in auditory cortex.

Is primate tool use special? Chimpanzee and New Caledonian crow compared

The chimpanzee ( Pan troglodytes ) is well-known in both nature and captivity as an impressive maker and user of tools, but recently the New Caledonian crow ( Corvus moneduloides ) has been championed as being equivalent or superior to the ape in elementary technology. I systematically compare the two taxa, going beyond simple presence/absence scoring of tool-using and -making types, on four more precise aspects of material culture: (i) types of associative technology (tools used in combination); (ii) modes of tool making; (iii) modes of tool use; and (iv) functions of tool use. I emphasize tool use in nature, when performance is habitual or customary, rather than in anecdotal or idiosyncratic. On all four measures, the ape shows more variety than does the corvid, especially in modes and functions that go beyond extractive foraging. However, more sustained field research is required on the crows before this contrast is conclusive.

Sound Processing Hierarchy within Human Auditory Cortex

Both attention and masking sounds can alter auditory neural processes and affect auditory signal perception. In the present study, we investigated the complex effects of auditory-focused attention and the signal-to-noise ratio of sound stimuli on three different auditory evoked field components (auditory steady-state response, N1m, and sustained field) by means of magnetoencephalography. The results indicate that the auditory steady-state response originating in primary auditory cortex reflects the signal-to-noise ratio of physical sound inputs (bottom–up process) rather than the listener's attentional state (top–down process), whereas the sustained field, originating in nonprimary auditory cortex, reflects the attentional state rather than the signal-to-noise ratio. The N1m was substantially influenced by both bottom–up and top–down neural processes. The differential sensitivity of the components to bottom–up and top–down neural processes, contingent on their level in the processing pathway, suggests a stream from bottom–up driven sensory neural processing to top–down driven auditory perception within human auditory cortex.

Insurgency redux: Writings on Thailand's ongoing southern war

Comprehending the origins, dynamics and solutions to the ongoing violence in southern Thailand's Muslim majority border provinces has proved to be a challenge, not only to successive Thai governments and security forces but also to scholars and other investigators. Insurgent-instigated attacks, now paralleled by and intertwined with more opportunistic forms of violence, have afflicted the border region for nearly seven years (as of late 2010), with no sign of ultimate abatement, despite a considerable investment of resources by the Thai state. Arguably under-reported by the world media, this conflict has nonetheless attracted its fair share of parachute journalism and superficial reportage by instant-experts, single-issue rights advocates, wide-eyed postgraduate researchers and assorted cranks. Many of them have been ensnared by local ‘fixers’ with their own agendas. Despite some notable exceptions, much academic research effort in the region itself has been hit-and-run. As Duncan McCargo emphasises: ‘this is a messy, awkward, in-your-face conflict’ (p. 188) — as such it demands a comparable ‘in-your-face’ and sustained field-based research effort, which, as he rightly notes, has been sadly lacking.

Attempted new association biological control of Dicranosterna semipunctata Chapuis (Coleoptera Chrysomelidae Paropsini)

The new association theory of biological control predicts that novel enemies may be more effective in controlling pest species than their natural enemies This theory was tested using the egg parasitoid Enoggera nassaui Girault (Hymenoptera Pteromalidae) on the Acacia tortoise beetle Dicranosterna semipunctata (Chapuis) (Coleoptera Chrysomelidae) in New Zealand In no choice laboratory bioassays parasitism on the new host was significantly lower than on a natural host Paropsis charybdis Stål (Coleoptera Chrysomelidae) (57 cf 89 eggs/h P002) The fecundity and oviposition rate of D semipunctata were approximately half that of P charybdis A field release of 1500 E nassaui directed against D semipunctata did not result in sustained field parasitism It is suspected that E nassaui will not normally encounter D semipunctata because it searches Eucalyptus not Acacia species The ability of biological control agents to locate the target species in the field needs to be considered when evaluating new association biological control